CN1929895B - Emissions reduction assembly and method of operation - Google Patents

Abstract

An emission reduction assembly for removing soot from exhaust gases of an internal combustion engine is disclosed. The assembly includes a particulate filter, a fuel-fired burner positioned upstream of the particulate filter, and a controller configured to control the fuel-fired burner, the controller including (i) a processor and (ii) a memory device electrically coupled to the processor, the memory device storing a plurality of instructions that, when executed by the processor, cause the processor to: determine whether the engine is operating under predetermined operating conditions; and, if the engine is operating under the predetermined operating conditions, operate the fuel-fired burner to regenerate the particulate filter. A method of operating the emission reduction assembly is also disclosed.

Description

Emissions reduction assembly and method of operation

technical field

The present invention relates generally to diesel engine emission reduction devices.

Background technique

Untreated emissions from internal combustion engines (eg, diesel emissions) include, for example, various waste waters such as NOx, hydrocarbons, carbon monoxide, and the like. In addition, untreated emissions from certain types of internal combustion engines, such as diesel engines, also include particulate carbon-based matter or "soot." Federal government regulations related to soot emission standards have become increasingly stringent, thereby promoting the need for devices and/or methods to remove soot from engine emissions.

The amount of soot emitted by an engine system can be reduced through the use of emission reduction devices such as filters or traps. Such filters or collectors require periodic regeneration in order to remove the soot therefrom. The filter or collector can be regenerated by burning the soot collected in the filter using a burner or electric heater.

Contents of the invention

According to one aspect of the invention, an emissions reduction assembly includes a pair of fuel fired burners. Both fuel fired burners are under the control of a single control unit. The fuel fired burner is selectively operable by the control unit to regenerate the particulate filter.

According to another aspect of the invention, a method of monitoring a fuel-fired burner during filter regeneration includes determining a temperature of heat generated by the burner and adjusting the amount of fuel supplied to the burner based thereon. A predetermined temperature range may be used and the amount of fuel supplied to the burner adjusted if the temperature is outside the predetermined temperature range. An electronic controller configured to control the fuel fired burner in such a manner is also disclosed. Temperature measurements may be obtained by using a temperature sensor.

According to another aspect of the invention, a control unit for controlling the operation of a fuel fired burner is disclosed. The control unit includes a housing with an air inlet opening into an interior chamber of the housing. An air pump is positioned within the interior chamber of the housing and has an air inlet opening toward the interior chamber of the control unit housing. The air pump creates a reduced air pressure in the internal chamber, which draws air into the housing and into the inlet of the pump. This airflow cools the electronic controller as well as other components housed within the housing. In one exemplary embodiment, an air pump draws air from the interior cavity of the housing and supplies the air to the combustion chamber of the fuel-fired burner, thereby facilitating operation of the burner. A related method of feeding air into a fuel-fired combustor is also disclosed.

According to another aspect of the invention, a method of operating a fuel-fired combustor of an emissions reduction assembly is disclosed. The method includes supplying reduced fuel to the fuel fired burner in response to detection of a burner shutdown request. Such reduced fuel supply continues for a predetermined period of time after which no more fuel is supplied to the burner. In the exemplary embodiment described here, along with spark generation, the supply of both combustion air and atomizing air continues for a period of time after the fuel is cut off. After a period of time, the combustion air is no longer supplied to the burner, but the supply of atomizing air continues and the spark is maintained. After a period of time, the supply of atomizing air is cut off and spark generation ceases. In the exemplary embodiment described herein, the purge air supply is supplied substantially continuously to the fuel-fired combustor to reduce or even prevent clogging of the combustor's fuel inlet nozzle. An electronic controller configured to control components of the emissions reduction assembly in such a manner is also disclosed.

According to another aspect of the present invention, a method of monitoring engine performance as a function of soot accumulation in a particulate filter, comprising: determining a characteristic of soot accumulation in said filter; analyzing the characteristic; and if the characteristic An error signal is generated indicating a predetermined engine performance condition. In an exemplary embodiment, the rate of soot accumulation in the filter may be monitored. An increase in the rate of soot accumulation in the filter (beyond a predetermined limit) may indicate an engine condition such as overfueling or a stuck/leaking fuel injector. Also disclosed herein is an electronic controller configured to monitor soot buildup in such a manner.

According to another aspect of the invention, a soot detector is used to detect the presence of fuel particles and/or soot in the inner chamber of the control unit. If the presence of fuel particles and/or soot is detected, the control unit may be shut down, thereby potentially avoiding damage to the control unit. A method of monitoring the output of such a smoke detector is also disclosed.

According to another aspect of the invention, a temperature sensor is used to monitor the temperature in the interior of the control unit. If the temperature exceeds a predetermined upper temperature limit, the control unit may be shut down, potentially avoiding damage to the control unit. A method of monitoring the output of such a temperature sensor is also disclosed.

According to another aspect of the invention, a fuel pressure sensor is used to monitor the fuel pressure in the fuel return line associated with the fuel pump of the control unit. If the fuel pressure in the return line exceeds a predetermined upper pressure limit, the control unit may be shut down, potentially avoiding damage to the control unit. A method of monitoring the output of such a fuel pressure sensor is also disclosed.

According to another aspect of the present invention, a method of monitoring ash accumulation in a particulate filter includes: determining particulate accumulation in the filter after regeneration of the filter; and generating an error signal if the particulate accumulation exceeds a predetermined threshold . Particulate matter remaining in the filter after filter regeneration may be due to ash. Also, by monitoring the amount of particulate matter in the filter relatively soon, if not immediately, after filter regeneration, it can be determined when the filter requires maintenance to remove ash. An electronic controller configured to monitor ash accumulation in such a manner is also disclosed.

According to another aspect of the invention, the electronic controller of the emission reduction assembly is electrically coupled to an engine control unit of the internal combustion engine. The electronic controller may be coupled to the engine control unit via a communication interface such as a controller area network or "CAN" interface. In this way, information can be shared between the electronic controller of the emission reduction assembly and the engine control unit.

According to another aspect of the present invention, a method of operating a fuel-fired burner, comprising: monitoring the temperature at the outlet of a particulate filter during a filter regeneration cycle; and if the filter outlet temperature exceeds said predetermined limit The operation of the fuel burner is then adjusted. In one embodiment, the fuel fired burner is switched off if the filter outlet temperature exceeds said predetermined temperature limit. Prior to or instead of shutting down the burner, the amount of fuel supplied to the fuel fired burner may be reduced if the filter outlet temperature exceeds a predetermined temperature limit.

According to another aspect of the invention, a method of starting a fuel-fired combustor of an emission reduction assembly includes reducing a rate of fuel supplied to the combustor upon detection of ignition. This fuel rate is kept low while the components warm up. Once preheating has occurred, the fuel level is increased to a predetermined operating fuel level.

According to another aspect of the invention, the electrodes of the fuel-fired burner are energized for a predetermined period of time before fuel is introduced into the burner to remove soot or other residue deposited on the electrodes.

According to another aspect of the invention, engine operating conditions are monitored to facilitate airless filter regeneration. In a specific embodiment, filter regeneration occurs when engine operating conditions are within a predetermined range.

According to another aspect of the invention, the exhaust flow entering through the air intake of the fuel fired burner is divided into a combustion flow which proceeds through the combustion chamber and a bypass flow which bypasses the combustion chamber.

According to another aspect of the invention, soot loading in the particulate filter is monitored as a function of exhaust mass flow.

According to another aspect of the present invention, there is provided a method of operating an emission reduction assembly to remove soot from the exhaust of an internal combustion engine, the method comprising the steps of:

determining whether the engine is operating under predetermined operating conditions, and

If the engine is operating under the predetermined operating conditions, the fuel fired burner is operated to regenerate the particulate filter.

According to another aspect of the present invention, there is provided an emission reduction assembly for removing soot from the exhaust of an internal combustion engine, the assembly comprising:

particle filter,

a fuel fired burner positioned upstream of the particulate filter, and

A controller configured to control the fuel-fired burner, the controller includes (i) a processor and (ii) a memory device electrically coupled to the processor, the memory device stores a plurality of instructions, and when passed through the When executed by the processor, these instructions cause the processor to:

determining whether the engine is operating under predetermined operating conditions, and

If the engine is operating under the predetermined operating conditions, the fuel fired burner is operated to regenerate the particulate filter.

Description of drawings

Figure 1 is a rear view of an on-highway truck with an emission reduction assembly installed thereon;

2 is a perspective view of one of the soot reduction assemblies of the emission reduction assembly of FIG. 1;

Figure 3 is a front view of the end of the soot reduction assembly viewed from the direction of the arrow on line 3-3 of Figure 2;

Fig. 4 is a cross-sectional view of the soot reducing assembly of Fig. 2 taken along line 4-4 of Fig. 3 viewed from the direction of the arrow;

5 is an enlarged cross-sectional view of the fuel-fired burner of the soot reduction assembly of FIG. 4;

Figure 6 is a perspective view of the control unit of the emission reduction assembly of Figure 1, noting that the cover has been removed for clarity;

Fig. 7 is a side view of the control unit of Fig. 6;

FIG. 8 is an illustration of the emission reduction assembly of FIG. 1;

9 is a flowchart of a control routine for monitoring operation of a fuel-fired burner of an emission reduction assembly during a filter regeneration cycle;

FIG. 10 is an exemplary temperature graph illustrating the manner in which the control routine of FIG. 9 is performed;

Figure 11 is a flowchart of a control program for monitoring filter outlet temperature during a filter regeneration cycle;

12 is a flowchart of a control routine for monitoring engine performance as a function of soot buildup in the particulate filter of the emission reduction assembly of FIG. 1;

FIG. 13 is an exemplary ΔP-time diagram illustrating the manner in which the control program of FIG. 12 is performed;

14 is a flowchart of a control routine for monitoring ash accumulation in the particulate filter of the emission reduction assembly of FIG. 1;

15 is a flowchart of a control routine for shutting down the fuel-fired burners of the emissions reduction assembly of FIG. 1;

FIG. 16 is an exemplary fuel level versus time diagram illustrating the manner in which the control routine of FIG. 15;

17 is a flowchart of a control routine for monitoring the fuel pressure in the fuel return line of the control unit;

Figure 18 is a flowchart of a control program for monitoring the output of a smoke detector from a control unit;

19 is a flowchart of a control program for monitoring the output of a temperature sensor from a control unit;

Figure 20 is an illustration of another emission reduction assembly;

21 is a view similar to FIG. 20 but showing the emission reduction assembly configured with a diesel oxidation catalyst upstream of the filter base;

Figures 22 and 23 are illustrations of a fuel fired burner showing the assembly of Figures 20 and 21 in greater detail;

Figure 24 is a perspective view showing in greater detail a portion of the combustion chamber of the assembly of Figures 20 and 21;

Figure 25 is a front view of a portion of the combustion chamber viewed from the direction of arrows 25-25 of Figure 24;

Figure 26 is a front view of the gas distributor;

Figure 27 is a view similar to Figures 22 and 23 but showing a different embodiment of the combustion chamber;

Figure 28 is a front view of the gas distributor;

Figure 29 is a diagram showing the engine and emission reduction components under the control of the engine's engine control unit;

30 is a flowchart of a control routine for initiating a fuel-fired burner of the emissions reduction assembly of FIG. 1;

FIG. 31 is an exemplary fuel level versus time diagram illustrating the manner of the control routine of FIG. 30;

Figure 32 is a flowchart of a control routine for cleaning electrodes of a fuel fired burner;

33 is a flowchart of a control routine for regenerating an airless fuel-fired combustor;

Figure 34 is a flowchart of a control routine for triggering filter regeneration;

Figure 35 is an illustration of another emission reduction assembly;

Figures 36-43 are views similar to Figure 5 but showing a modified fuel fired burner;

Figure 44 is an expanded view of a plate positionable about the combustion chamber; and

45 is a partial perspective view showing the plate of FIG. 44 positioned about the combustion chamber.

Detailed ways

As described in more detail below, the emission reduction assembly 10 for use with an internal combustion engine, such as a diesel engine of an on-highway truck 12 , includes a pair of soot reduction assemblies 14 , 16 under the control of a control unit 18 . As shown in FIG. 1, each of the soot reduction assemblies 14, 16 has a fuel fired burner 20, 22 and a particulate filter 24, 26, respectively. The fuel fired combustors 20 , 22 are positioned upstream (with respect to engine exhaust flow) of the respective particulate filters 24 , 26 . During engine operation, the exhaust gas flows through the particulate filters 24, 26 collecting soot in the filters. The treated exhaust gas is released to the atmosphere through exhaust ducts 28 , 30 . The control unit 18 selectively operates the fuel fired combustor 20 to regenerate the particulate filter and the fuel fired combustor 22 to regenerate the particulate filter 26 from time to time during engine operation.

Referring now to FIGS. 2-5 , the soot reduction assembly 14 is shown in greater detail. It should be understood that the soot reduction assembly 14 is substantially the same as the soot reduction assembly 16 . As such, discussions related to the soot reduction assembly 14 of FIGS. 2-5 also relate to the soot reduction assembly 16 .

As shown in FIG. 5 , the fuel-fired combustor 20 of the soot reduction assembly 14 includes a housing 32 having a combustion chamber 34 positioned therein. The housing 32 includes an exhaust gas inlet 36 . As shown in FIG. 1 , the exhaust inlet 36 is secured to a T-shaped exhaust pipe 38 which directs exhaust from the diesel engine of the truck 12 to the soot reduction assemblies 14 , 16 .

A plurality of gas inlet openings 40 are defined in the combustion chamber 34 . Engine exhaust gases can flow into the combustion chamber 34 via the inlet opening 40 . In this way, the ignition flame present inside the combustion chamber 34 is prevented from encountering the entire flow of engine exhaust gas while allowing a controlled amount of engine exhaust gas to enter the combustion chamber 34 to provide oxygen to facilitate combustion of the fuel supplied to the combustor 20 . Exhaust gases that do not enter the combustion chamber 34 are directed out of an outlet 46 of the housing 32 through a plurality of openings 42 defined in the shroud 44 .

The fuel fired combustor 20 includes an electrode assembly having a pair of electrodes 48 , 50 . As discussed in more detail below, electrodes 48 , 50 are electrically coupled to an igniter of control unit 18 . When the electrodes 48 , 50 are energized, a spark is generated in the gap 52 between the electrodes 48 , 50 . Fuel enters the fuel fired burner 20 through a fuel inlet nozzle 54 and proceeds through a gap 52 between the electrodes 48, 50 so that a spark generated by the electrodes 48, 50 ignites the fuel. It should be understood that fuel entering nozzle 54 is generally in the form of a controlled air/fuel mixture.

The fuel fired combustor 20 also includes a combustion air inlet 56 . As discussed in more detail below, an air pump associated with control unit 18 generates a flow of pressurized air that is fed to combustion air inlet 56 via air line 58 ( FIG. 1 ). During regeneration of the particulate filter 24, air flow is introduced to the fuel fired combustor 20 through the combustion air inlet 56 to provide oxygen (in addition to the oxygen present in the exhaust) for sustained combustion of the fuel.

As shown in FIGS. 2 and 4 , the particulate filter 24 is positioned downstream (relative to the flow of exhaust) of the outlet 46 of the housing 32 of the fuel fired combustor 20 . The particulate filter 24 includes a filter substrate 60 . As shown in FIG. 4 , base 60 is positioned within housing 62 . The filter housing 62 is fixed to the burner housing 32 . In this manner, gases exiting the combustor housing 32 are directed into the filter housing 62 and through the substrate 60 . Particulate filter 24 may be any type of commercially available particulate filter. For example, the particulate filter 24 may be implemented as an exhaust particulate filter such as a "deep bed" or "wall flow" filter. Deep bed filters can be realized as metal mesh filters, metal or ceramic foam filters, ceramic fiber mesh filters, etc. A wall flow filter, on the other hand, may be a cordierite or silicon carbide ceramic filter with alternating channels inserted in its front and rear so that the gas is forced through the wall into one channel, And come out from another channel. Additionally, the filter substrate 60 may be impregnated with a catalytic material, such as, for example, a noble metal catalytic material. For example, the catalytic material may be implemented in platinum, rhodium, palladium, including combinations thereof, and any other similar catalytic material. The use of catalytic materials reduces the temperature required to ignite the collected soot particles.

The filter housing 62 is fixed to the housing 64 of the collector 66 . Specifically, the outlet 88 of the filter housing 62 is fixed to the inlet 68 of the collector housing 64 . As such, treated (ie, filtered) exhaust exiting filter base 60 (and thus filter housing 62 ) proceeds into collector 66 . The treated exhaust gas then proceeds into the exhaust pipe 28 and is thereby released to the atmosphere through the gas outlet 70 . It should be understood that if the truck 12 is equipped with subsequent emission reduction devices (not shown), the gas outlet 70 may be coupled to the inlet of such a device (or to the piping of the inlet).

Referring now to Figures 6-8, the control unit 18 is shown in greater detail. The control unit 18 includes a housing 72 that defines an interior chamber 112 . A number of components associated with the control unit 18 are positioned within the interior chamber 112 of the housing 72 . For ease of illustration, the sealing cover 74 (see FIG. 1 ) has been removed from the housing in FIGS. 6 and 7 to expose the components in the housing 72 . Control unit 18 includes an electronic control unit (ECU) or “electronic controller” 76 . Electronic controller 76 is positioned within interior chamber 112 of housing 72 . In effect, electronic controller 76 is responsible for interpreting electrical signals sent by sensors associated with emission reduction assembly 10 (and in some cases engine 80 ) and for actuating electronically controlled components associated with emission reduction assembly 10 main computer. For example, among other things, the electronic controller 76 can be used to determine when one of the particulate filters 24, 26 of the soot reduction assemblies 14, 16 needs to be regenerated, calculate and control the ratio of air and fuel to be introduced into the fuel-fired combustors 20, 22. Quantities and ratios, determining temperatures at various locations in the soot reduction assemblies 14 , 16 , operating various air and fuel valves, and communicating with the engine control unit 78 associated with the engine 80 of the truck 12 .

To this end, the electronic controller 76 includes a plurality of electronic components generally associated with electronic units used in the control of electromechanical systems. For example, the electronic controller 76 may include a processor, such as a microprocessor 82, and a storage device 84, such as a programmable read-only memory device ("PROM"), among other components typically included in such devices, wherein Programmable read-only memory devices include erasable PROMs (EPROMs or EEPROMs). Among other things, memory device 84 is used to store instructions, such as in the form of a software program (or programs), which when executed by processor 82 cause electronic controller 76 to control the operation of emission reduction assembly 10 .

Electronic controller 76 also includes analog interface circuitry 86 . Analog interface circuitry 86 converts output signals from various sensors (eg, temperature sensors) into signals suitable for presentation to the input of microprocessor 82 . Specifically, the analog interface circuit 86 converts an analog signal generated by the sensor into a digital signal used by the microprocessor 82 by using an analog-to-digital (A/D) converter (not shown) or the like. It should be understood that the A/D converter may be implemented as a discrete device or multiple devices, or may be integrated into the microprocessor 82 . It should be understood that analog interface circuit 86 may be bypassed if any one or more of the sensors associated with emission reduction assembly 10 produces a digital output signal.

Similarly, analog interface circuitry 86 converts signals from microprocessor 82 into output signals suitable for presentation to electrically controlled components associated with emission reduction assembly 10 (e.g., fuel injectors, air valves, igniters, pump motors, etc.) . Specifically, analog interface circuit 86 converts the digital signals generated by microprocessor 82 into electronic signals associated with emission reduction assembly 10 by utilizing devices such as digital-to-analog (D/A) converters (not shown). Analog signal used by the controlled part. It should be understood that, similar to the A/D converter described above, the D/A converter may be implemented as a discrete device or multiple devices, or may be integrated into the microprocessor 82 . It should be appreciated that analog interface circuit 86 may be bypassed if any one or more of the electrically controlled components associated with emission reduction assembly 10 operate on analog input signals.

Accordingly, electronic controller 76 is operable to control the operation of fuel fired burners 20 and 22 . Specifically, electronic controller 76 executes a program that includes a closed-loop control mode in which electronic controller 76 monitors the output of sensors associated with emission reduction assembly 10 to control the supply of input to the control unit. To this end, the electronic controller 76 communicates with sensors associated with the emission reduction components to determine the temperature at various locations within the soot reduction components 14 , 16 and the pressure drop across the filter base 60 . Equipped with this data, the electronic controller 76 performs many calculations per second, including looking up values in pre-programmed tables, in order to execute algorithms to perform functions such as determining when to operate a fuel injector or for how long to operate a fuel injector. timing, controlling power level input to electrodes 48 and 50, controlling air advancing through combustion air inlet 56, and the like.

The control unit 18 also includes an air pump 90 . The air pump 90 is driven by a motor 92 which is under the control of the electronic controller 76 . Motor 92 drives pulley 94 , which in turn drives air pump 90 . Signal line 96 electrically couples air pump 90 to electronic controller 76 . An outlet 98 of the air pump 90 is coupled via an air line 104 to an inlet 100 of an electronically controlled air valve 102 . The first outlet 106 of the air valve 102 is coupled to the combustion air inlet 56 of the fuel fired burner 20 via one of the air lines 58, while the second outlet 108 of the air valve 102 is coupled to Combustion air inlet 56 of fuel fired burner 22 .

Air valve 102 is electrically coupled to electronic controller 76 via signal line 110 . In this way, the electronic controller 76 can control the position of the valve 102 . Specifically, the electronic controller 76 can position the air valve 102 in a first valve position, in which combustion air from the air pump 90 is directed to the fuel-fired burner 20, or in a second valve position, in the second valve position. position, the combustion air from the air pump 90 is directed to the fuel fired burner 22 . As described in more detail below, the controller 76 operates the air valve 102 to direct combustion air to the fuel fired combustors 20 , 22 associated with the particulate filters 24 , 26 being regenerated.

As shown in FIGS. 6 and 7 , the inlet 114 of the air pump 90 opens into the interior chamber 112 of the control housing 72 . Thus, the air pump 90 draws air from the interior chamber 112 of the control housing 72 . The control housing 72 has an air inlet 116 . The air inlet 116 opens into the interior chamber 112 . An air filter 118 is secured to housing 72 and positioned to filter air drawn into interior chamber 112 through air inlet 116 . When operating, the air pump 90 generates a reduced air pressure within the interior chamber 112 , thereby drawing air from the atmosphere into the interior chamber 112 via the filter 118 /air inlet 116 . The air in the interior chamber 112 is then drawn into the pump inlet 114 and pumped to the air valve 102 . When the cover 74 is fixed in place (as in FIG. 1 ), the housing 72 is substantially sealed such that substantially all of the air drawn into the interior chamber 112 by the air pump 90 is drawn through the filter 118 (and thus through the air entrance 116).

Since the pump inlet 114 and the housing inlet 116 are both open to the interior chamber 112 (as opposed to being coupled to each other, for example, by an air hose or other type of conduit), when air travels from the housing inlet 116 to the pump inlet 114, the inner chamber An air flow is generated in the chamber 112 . Such an arrangement facilitates cooling of the electronic controller 76 since the controller 76 is exposed to at least a portion of the air flow within the interior chamber 112 . Specifically, electronic controller 76 generates heat during its operation. Heat from the electronic controller 76 is transferred to the air passing through the interior chamber 112 , cooling the electronic controller 76 . Such an arrangement facilitates placement of the controller 76 within the housing 72 (as opposed to locating the controller 76 outside of the housing 72 so as to be exposed to ambient ambient temperatures). Furthermore, in certain embodiments, cooling the electronic controller 76 in this manner eliminates the need for a heat sink or other heat sink.

The electronic control unit 18 also includes a fuel delivery assembly 120 configured to supply a desired mixture of air and fuel (“air/gas mixture”) to the fuel fired burners 20 , 22 . Specifically, the fuel-fired combustors 20, 22 combust or otherwise process fuel in the form of an air and fuel mixture. As defined herein, the term "air/fuel mixture" is defined to mean any mixture of any amount of air and any amount of fuel, including a "mixture" of fuel alone. Furthermore, the term "air to fuel ratio" is intended to mean the relationship between the air component and the fuel component in such an air/fuel mixture.

An exemplary embodiment of fuel delivery assembly 120 is described in more detail below. However, it should be understood that such description is exemplary in nature and that the fuel delivery assembly 120 may be implemented in a variety of different configurations.

In the embodiment illustrated here, the fuel delivery assembly 120 includes a fuel pump 122 that draws diesel fuel from a fuel tank 124 of the truck 12 via a fuel line 126 . Fuel filter 128 filters fuel drawn from fuel tank 124 . As shown in FIGS. 6 and 7 , the motor driven pulley 94 drives the input shaft 130 of the fuel pump 122 . Thus, electric motor 92 drives both air pump 90 and fuel pump 122 .

The fuel pump 122 supplies a pressurized flow of fuel to a pair of electronically controlled fuel injectors 132 , 134 . As shown in FIG. 8 , signal lines 136 electrically couple fuel injector 132 to electronic controller 76 , thereby allowing controller 76 to control operation of injector 132 . Similarly, signal lines 138 electrically couple fuel injectors 134 to electronic controller 76 , thereby enabling controller 76 to control operation of injectors 134 .

An electronically controlled fuel priming valve 140 selectively supplies fuel from the fuel pump 122 to the fuel injectors 132 , 134 . Specifically, fuel activation valve 140 allows fuel to advance to fuel injectors 132 , 134 when positioned in an open valve position. However, fuel cannot be supplied to the fuel injectors 132 , 134 when the fuel activation valve 140 is positioned in the closed valve position. Fuel drawn by pump 122 that is not supplied to injectors 132 , 134 is returned to truck fuel tank 124 via fuel return line 142 . Fuel priming valve 140 is electrically coupled to electronic controller 76 via signal line 144 . Electronic controller 76 generates an output signal on signal line 144 for controlling operation (eg, positioning) of fuel activation valve 140 .

Fuel injectors 132, 134 are selectively operated by electronic controller 76 to inject a quantity of fuel into mixing chamber 146 where the fuel mixes with air to produce an air/fuel mixture having a desired air to fuel ratio, The air/fuel mixture is then delivered to the fuel inlet nozzles 54 of the fuel fired combustors 20 , 22 via a pair of fuel lines 148 , 150 . Specifically, electronic controller 76 generates an output signal on signal line 136 causing fuel injector 132 to inject a certain desired amount of fuel into mixing chamber 146 where it is mixed with air and delivered via fuel line 148 to Fuel inlet nozzle 54 of fuel fired burner 20 . Similarly, electronic controller 76 generates an output signal on signal line 136 causing fuel injector 134 to inject a specific desired amount of fuel into mixing chamber 146 where it is mixed with air and delivered via fuel line 150 to Fuel inlet nozzle 54 of fuel fired burner 22 .

In the exemplary embodiment described herein, the air delivered to the mixing chamber 146 is supplied from a pressurized air source 150 associated with the truck 12 . For example, the pressurized air source 150 may be a truck's pneumatic brake pump. Pressurized air from an air source 150 is supplied to the control unit 18 via an air line 152 . A pair of electronically controlled air valves 154 , 156 control the amount of air supplied to the mixing chamber 146 .

The air valve 154 supplies a flow of clean air, as described in more detail below, that is typically supplied constantly to the mixing chamber 146 during operation of the engine 80 of the truck 12 . Such air flow prevents the accumulation of residues, such as soot, in the fuel inlet nozzles 54 of the fuel fired burners 20 , 22 . Such clean air flow may be pulsed at higher pressures at short intervals to reduce clogging of nozzles 54 by soot or other residues. For example, under software control, the clean air flow can be pulsed such that air is supplied, for example, at 60 psi for 15 seconds, then cut off (or pressure reduced) for 45 seconds, then pulsed again, and so on. It has been found that such rapid increases in air pressure create a force or "shock" that facilitates removal of the soot.

As shown in FIG. 8 , air valve 156 is positioned in a parallel flow arrangement with clean air valve 154 . Air valve 156 supplies air flow that is combined with the air flow from clean air valve 154 . This combined air flow is used for fuel atomization during operation of the fuel fired combustors 20 , 22 . Thus, during regeneration of one of the particulate filters 24, 26, both the atomizing air valve 156 and the clean air valve 154 are positioned in their respective open positions for supplying air to the mixing chamber 146, Fuel injected by fuel injectors 132 , 134 into mixing chamber 146 is thereby atomized.

Clean air valve 154 is electrically coupled to electronic controller 76 via signal line 158 . Electronic controller 76 generates an output signal on signal line 158 for controlling the operation (eg, positioning) of clean air valve 154 . Similarly, atomizing air valve 156 is electrically coupled to electronic controller 76 via signal line 160 . Electronic controller 76 generates an output signal on signal line 160 for controlling the operation (eg, positioning) of atomizing air valve 156 .

Air exiting the air valves 154 , 156 is supplied to the mixing chamber 146 via an air line 162 as shown in FIG. 8 . Pressure transducer 164 senses air pressure in air line 162 . The output of converter 164 is communicated to electronic controller 76 via signal line 166 . The output of transducer 164 may be utilized by electronic controller 76 to verify that the desired airflow is being supplied to mixing chamber 146 . For example, in the exemplary embodiment described herein, the air-to-fuel ratio of the air/fuel mixture supplied to the fuel-fired combustors 20, 22 is maintained substantially constant with the amount of air supplied to the mixing chamber 146 The lower is changed by changing the amount of fuel injected into the mixing chamber 146 . Thus, the output of pressure transducer 164 may be monitored by electronic controller 76 to determine the desired substantially constant air flow supplied to mixing chamber 146 .

As mentioned above, the fuel supply to the fuel fired burners 20, 22 is adjusted by varying the amount of fuel added to the substantially constant atomizing air flow. For example, to increase the amount of fuel supplied to fuel-fired combustor 20 (i.e., decrease the air-to-fuel ratio of the air/fuel mixture supplied to combustor 20), electronic controller 76 operates fuel injector 132, The amount of fuel injected into the fuel mixing chamber 146 is increased while the amount of air in the chamber 146 remains substantially constant. Similarly, to increase the amount of fuel supplied to fuel-fired combustor 22 (i.e., decrease the air-to-fuel ratio of the air/fuel mixture supplied to combustor 22), electronic controller 76 operates fuel injector 134, The amount of fuel injected into the fuel mixing chamber 146 is increased while the amount of air in the chamber 146 remains substantially constant.

Conversely, to reduce the amount of fuel supplied to fuel-fired combustor 20 (i.e., increase the air-to-fuel ratio of the air/fuel mixture supplied to combustor 20), electronic controller 76 operates fuel injector 132, The amount of fuel injected into the fuel mixing chamber 146 is reduced while the amount of air in the chamber 146 remains substantially constant. To reduce the amount of fuel supplied to fuel-fired combustor 22 (ie, increase the air-to-fuel ratio of the air/fuel mixture supplied to combustor 22 ), electronic controller 76 operates fuel injector 134 to The amount of fuel injected into the fuel mixing chamber 146 is reduced while the amount of air in the fuel tank remains substantially constant.

As shown in FIG. 8 , pressure regulator 168 regulates the fluid pressure in mixing chamber 146 . Specifically, pressure regulator 168 ensures that a predetermined pressure is not exceeded in mixing chamber 146 . For example, in many commercial systems, the air from the truck pressurized air source 150 is 90 psi. Pressure regulator 168 reduces the pressure of the air delivered to mixing chamber 146 to a lower level, such as 40 psi.

The control unit 18 also includes a pair of ignition devices or igniters 170 , 172 . Igniters 170, 172 are electrically coupled to electronic controller 76 via signal lines 174, 176, respectively. Accordingly, controller 76 may selectively generate control signals on signal lines 174 , 176 to control operation of igniters 170 , 172 . Igniter 170 is electrically coupled to electrodes 48, 50 of fuel fired burner 20 via a high voltage cable 178, while igniter 172 is electrically coupled to electrode 48 of fuel fired burner 22 via a high voltage cable 180 , 50. Actuation of igniter 170 causes a spark to be generated across gap 52 between electrodes 48 , 50 of fuel fired burner 20 , thereby igniting the air/fuel mixture entering burner 20 through fuel inlet nozzle 54 . Similarly, actuation of igniter 172 causes a spark to be generated in gap 52 between electrodes 48 , 50 of fuel-fired combustor 22 , thereby igniting the air/fuel mixture entering combustor 22 through fuel inlet nozzle 54 .

The igniters 170 , 172 may be realized as any type of device suitable for generating a spark between the gap 52 of the electrodes 48 , 50 . For example, igniters 170, 172 may be used in one or more of U.S. Patent Application No. 10/737,333, filed December 16, 2003, entitled "Power Supply and Transformer" by Stephen P. Goldschmidt and Wilbur H. Crawley (attorney file No. 9501-73714, ArvinMeritor Company Document No. 03MRA0454) disclosed in the device to achieve. This patent application is hereby incorporated by reference in its entirety.

As noted above, the electronic controller 76 monitors the output of various sensors associated with the soot reduction assemblies 14 , 16 . For example, soot reduction assemblies 14 , 16 each include a flame temperature sensor 182 , a control temperature sensor 184 , and an outlet temperature sensor 186 . Temperature sensors 182, 184, 186 are electrically coupled to electronic controller 76 via signal lines 188, 190, 192, respectively. As shown in FIGS. 2-5, the temperature sensors 182, 184, 186 may be implemented as thermocouples extending through the housings of the soot reduction assemblies 14, 16, although other forms of sensors may also be used.

The electronic controller 76 monitors the output of the flame temperature sensor 182 to detect or otherwise determine the presence of an ignition flame in the combustion chamber 34 of the fuel fired burner 20 , 22 . Specifically, when electronic controller 76 initiates ignition of fuel-fired burners 20, 22, controller 76 may monitor the output of flame temperature sensor 182 to ensure that the air/fuel mixture entering 48, 50 sparks ignited. If the output of the flame temperature sensor 182 does not meet predetermined criteria, an error signal is generated.

The electronic controller 76 monitors the output of the control temperature sensor to adjust the fuel supply to the fuel fired burners 20, 22 to maintain the temperature of the heat applied to the particulate filters 24, 26 within a predetermined range. For example, the temperature control range may be designed to allow sufficient heat to adequately regenerate the particulate filters 24 , 26 while simultaneously preventing the filters 24 , 26 from being at excessively high temperatures that could damage the filters 24 , 26 . It should be understood that the temperature control range may be designed to serve other purposes.

An exemplary temperature control routine 200 for controlling the fuel fired burners 20 , 22 during filter regeneration is shown in FIGS. 9 and 10 . The control routine 200 begins with step 202 in which the electronic controller 76 determines the temperature of the heat generated by the burner. Specifically, electronic controller 76 scans or otherwise reads signal line 190 to monitor and control the output of temperature sensor 184 . Once the electronic controller 76 has determined the temperature of the heat generated by the fuel fired burners 20 , 22 , the routine proceeds to step 204 .

In step 204, the electronic controller 76 determines whether the temperature of the heat generated by the fuel fired burners 20, 22 is within a predetermined temperature control range. Specifically, a predetermined temperature control range may be established as described herein. In the exemplary embodiment described herein, a target temperature (eg, 650° C. degrees Celsius, 350 degrees Celsius in the case of catalyzed filters 24, 26). Thus, in step 204, the electronic controller 76 determines whether the sensed temperature of the heat generated by the fuel-fired burners 20, 22 is within a predetermined temperature control range (ie, less than the upper limit and greater than the lower limit) . If the temperature of the heat generated by the fuel fired burners 20 , 22 is within the predetermined temperature control range, the control routine 200 loops back to step 202 to continue monitoring the output of the control temperature sensor 184 . However, if the temperature of the heat generated by the fuel-fired burners 20, 22 is not within the predetermined temperature control range, a control signal is generated—if the temperature of the heat generated by the fuel-fired burners 20, 22 is higher than the above The control limit then proceeds to step 206 and if the temperature of the heat generated by the fuel fired burner 20 , 22 is below the lower control limit then proceeds to step 208 .

In step 206 , the electronic controller 76 reduces the fuel supplied to the fuel fired burners 20 , 22 . To this end, electronic controller 76 increases the air to fuel ratio of the air/fuel mixture supplied to combustors 20 , 22 by reducing the amount of fuel injected by fuel injectors 132 , 134 into mixing chamber 146 . For example, to reduce the fuel supplied to fuel-fired burner 20, electronic controller 76 generates a control signal on signal line 136 that reduces the amount of fuel injected by fuel injector 132 into mixing chamber 146, thereby increasing Line 148 supplies the air to fuel ratio of the air/fuel mixture to combustor 20 . Similarly, to reduce the fuel supplied to fuel-fired burner 22, electronic controller 76 generates a control signal on signal line 138 that reduces the amount of fuel injected by fuel injector 134 into mixing chamber 146, thereby increasing the Fuel line 150 supplies the air to fuel ratio of the air/fuel mixture to fuel fired combustor 22 . Once the fuel supplied to the fuel fired burners 20 , 22 has been reduced, control proceeds to step 210 .

In step 210, electronic controller 76 determines whether the out-of-range condition of step 206 is recurring. More specifically, the controller 76 determines whether a predetermined number of temperature readings have been outside the control range. Specifically, the electronic controller 76 monitors the results of previous fuel adjustments to determine whether the fuel-fired burners 20, 22 have returned to operation within a predetermined temperature control range. If the controller 76 determines that a predetermined number of temperature readings have been outside the control range, the electronic controller 76 concludes that the fuel-fired burners 20, 22 cannot resume control, generates an error signal, and the control routine 200 proceeds to Step 212. Otherwise, the control routine 200 loops back to step 202 to continue monitoring the operation of the fuel fired combustors 20, 22 during filter regeneration.

In step 212 , the electronic controller 76 turns off the fuel fired burners 20 , 22 . Specifically, since the electronic controller 76 concluded in step 210 that the fuel-fired burner 20, 22 could not resume control, the controller 76 ceased fuel supply to the affected burner 20, 22, stopping at the electrode 48. , 50, or otherwise stop the operation of the affected burners 20, 22.

Returning to step 204 , if the temperature of the heat generated by the fuel fired burners 20 , 22 is below the lower control limit, control proceeds to step 208 . In step 208 , the electronic controller 76 increases the fuel supplied to the fuel fired burners 20 , 22 . To this end, electronic controller 76 reduces the air to fuel ratio of the air/fuel mixture supplied to combustors 20 , 22 by increasing the amount of fuel injected by fuel injectors 132 , 134 into mixing chamber 146 . For example, to increase the fuel supplied to fuel-fired burner 20, electronic controller 76 generates a control signal on signal line 136 that increases the amount of fuel injected by fuel injector 132 into mixing chamber 146, thereby reducing the amount of fuel injected by fuel injector 132. Line 148 supplies the air to fuel ratio of the air/fuel mixture to combustor 20 . Similarly, to increase the fuel supplied to fuel-fired burner 22, electronic controller 76 generates a control signal on signal line 138 that increases the amount of fuel injected by fuel injector 134 into mixing chamber 146, thereby reducing Fuel line 150 supplies the air to fuel ratio of the air/fuel mixture to combustor 22 . Once the fuel supplied to the fuel fired burners 20, 22 has been increased, control proceeds to step 210 where it is determined whether control of the fuel fired burners has resumed in the manner previously described.

The output of the output temperature sensor 186 may also be utilized by the electronic controller 76 to control the operation of the fuel fired combustors 20 , 22 during the regeneration of the particulate filters 24 , 26 . Specifically, as shown in FIG. 11 , the control routine 250 may be executed by the electronic controller 76 during filter regeneration. The control routine 250 begins with step 252 in which the electronic controller 76 determines the temperature at the outlet of the particulate filter 24,26. Specifically, electronic controller 76 scans or otherwise reads signal line 192 to monitor the output of outlet temperature sensor 186 . Once the electronic controller 76 has determined the temperature at the outlet of the particulate filter 24 , 26 , the program proceeds to step 254 .

In step 254, electronic controller 76 determines whether the sensed filter outlet temperature is above a predetermined upper temperature limit. If the filter outlet temperature is below the upper temperature limit, the control routine 250 loops back to step 25 to continue monitoring the output of the outlet temperature sensor 186 . However, if the filter outlet temperature is above the upper control limit, control routine 250 proceeds to step 256 .

In step 256, the electronic controller 76 turns off the fuel fired burners 20, 22. Specifically, since the electronic controller 76 concluded in step 254 that the filter outlet temperature is above the upper control limit, the controller 76 stops fuel supply to the affected burners 20, 22, stops at the electrodes 48, 50 sparks between, or otherwise ceases operation of the affected combustors 20, 22. Control program 250 then proceeds to step 258 .

In steps 258 and 260, the electronic controller 76 determines whether the filter outlet temperature has cooled to a temperature below the upper control limit. Specifically, in step 258 , electronic controller 76 scans or otherwise reads signal line 192 to monitor the output of outlet temperature sensor 186 to determine the temperature at the outlet of particulate filter 24 , 26 . Once the electronic controller 76 has determined the temperature at the outlet of the particulate filter 24 , 26 , the routine 250 proceeds to step 260 .

In step 260, electronic controller 76 determines whether the sensed filter outlet temperature is still above a predetermined upper temperature limit. If the filter outlet temperature is still above the upper control limit, the control routine 250 loops back to step 258 to continue monitoring the output of the outlet temperature sensor 186 . However, if the filter outlet temperature is now below the upper temperature limit, control routine 250 proceeds to step 262 .

In step 262 , the electronic controller 76 restarts the fuel fired burners 20 , 22 . Specifically, since the electronic controller 76 concluded in step 260 that the filter outlet temperature is now below the upper control limit, the controller 76 begins supplying fuel to the affected burners 20, 22, at the electrodes 48, 50 A spark is generated between them and otherwise restarts operation of the affected combustor 20, 22. The control routine 250 then loops back to step 250 to monitor the operation of the combustors 20 , 22 .

The electronic controller 76 also monitors the output of a plurality of pressure sensors associated with the soot reduction assemblies 14 , 16 . For example, soot reduction assemblies 14, 16 each include a filter inlet pressure sensor 264 and a filter outlet pressure sensor 266 (Fig. 8). Pressure sensors 264 and 266 are electrically coupled to electronic controller 76 via signal lines 268 and 270, respectively. The pressure sensors 264, 266 may be implemented with any form of pressure sensing device, such as, for example, commercially available pressure sensors.

Regeneration of the particulate filters 24 , 26 may be initiated as a function of the output of the pressure sensors 264 , 266 . For example, pressure sensors 264, 266 may be utilized to sense differential pressure across particulate filters 24, 26 (ie, "pressure drop" across the filter) to determine when filters 24, 26 require regeneration. Specifically, when the pressure drop across one of the particulate filters 24, 26 increases to a predetermined value, a filter regeneration process for that filter 24, 26 is initiated. It should be understood that the pressure sensors 264, 266 may be implemented as a single sensor. Specifically, a single sensor that measures differential pressure can be used. Such a sensor has two input ports, one of which measures the pressure upstream of the filter and the other one measures the pressure downstream of the filter. In operation, such a sensor measures the differential pressure across its ports and generates a signal related to the differential pressure. Furthermore, it should also be understood that in particular embodiments a single filter may be used on either of the filters 24,26. In such an arrangement, the output of the single pressure sensor is monitored to determine when the pressure exceeds a predetermined upper threshold or falls below a predetermined lower threshold (as opposed to monitoring the pressure drop across the filter).

It should be understood that the control scheme for initiating filter regeneration can be designed in a variety of different ways. For example, a timing-based control mode may be utilized wherein regeneration of the particulate filters 24, 26 is initiated as a function of time. For example, regeneration of the particulate filters 24, 26 may occur at predetermined timed intervals.

The output of the pressure sensors 264 , 266 may also be used in conjunction with other information to trigger regeneration of the particulate filters 24 , 26 . For example, the pressure drop across the filters 24 , 26 as a function of exhaust mass flow of the engine 80 may be used to trigger regeneration of the filters. For this purpose, data tables (for example maps) of the particle filters 24 , 26 are first generated experimentally. To generate such a map, the pressure drop across the filters 24, 26 is mapped as a function of exhaust mass flow for different particulate (soot) loadings. Specifically, the filters 24, 26 are first injected with a prescribed amount of soot. This amount of soot can indicate a load situation in which regeneration is performed under a desired load that requires regeneration. For example, if regeneration is required when a particular type of particulate filter 24, 26 is loaded to say 5.0 g/l, the filter used to experimentally generate the map is first pre-loaded with such an amount of soot (i.e. 5.0 g/l /l). Once preloaded, the pressure drop across the filter was measured experimentally at a number of different discharge mass flow rates. A look-up table (eg, a map) can then be generated that includes a plurality of experimentally derived pressure drop values, each pressure drop value corresponding to one of a plurality of different discharge mass flow values. Such a mapping may be programmed into controller 76 .

Such a map of experimentally derived pressure drop values can then be used to determine when to trigger regeneration. Specifically, during operation of the engine 80 , the controller 76 may determine the current pressure drop across the filters 24 , 26 and the exhaust mass flow of the engine 80 . The pressure drop may be determined by monitoring the output of the pressure sensors 264 , 266 as described herein. As described in more detail below, the controller 76 may determine discharge mass flow by monitoring the output of a mass flow sensor 892 (eg, FIG. 8 ), such as a hot wire mass flow sensor. It should be appreciated that the controller 76 may be in direct communication with the mass flow sensor 892, or obtain the output of the sensor 892 from the engine control unit 78 via the CAN interface 314 (which is described in detail below). Alternatively, exhaust mass flow may be controlled by controller 76 in a conventional manner by using engine operating parameters such as engine speed (RPM), turbo boost, and inlet manifold temperature (along with other known parameters such as engine displacement). Calculation. It should be understood that the controller 76 may calculate mass flow itself, or the calculated mass flow may be obtained from the engine control unit 78 via the CAN interface 314 .

Once the controller 76 has determined the pressure drop across the particulate filters 24, 26 and the exhaust mass flow of the engine 80, the controller 76 consults a lookup table (i.e., a map) for experimentally developed thresholds that corresponds to the sensed (calculated) exhaust mass flow of the engine 80 . The controller 76 then compares the sensed pressure drop across the particulate filters 24, 26 to the obtained threshold value. If the sensed pressure drop across the particulate filter 24, 26 exceeds the threshold obtained, the controller 76 determines that the filter 24, 26 requires regeneration and initiates a regeneration cycle.

FIG. 34 shows an example control routine 860 for triggering filter regeneration based on pressure drop across the filter as a function of exhaust mass flow. Routine 860 begins with step 862 where electronic controller 76 determines the pressure drop (ΔP) across filters 24 , 26 . Specifically, the controller 76 monitors the output of the pressure sensors 264, 266 and thereafter calculates the pressure drop (ΔP) across the filter. Control program 860 then proceeds to step 864 .

In step 864 , the controller 76 determines the exhaust mass flow of the engine 80 . As noted above, controller 76 may determine exhaust mass flow by monitoring the output of mass flow sensor 892, or by utilizing engine operating parameters such as engine RPM, turbo boost, and inlet manifold temperature (combined with other parameters such as engine displacement). known parameters together) to determine the discharge mass flow rate. In either case, control proceeds to step 866 once the controller determines the discharge mass flow.

In step 866, the controller 76 consults a lookup table (i.e., filter map) to obtain experimentally developed limit values corresponding to the sensed (calculated) exhaust mass flow rate (as determined in step 864) . Once the controller 76 obtains the limit value from the lookup table, the control routine 860 proceeds to step 868 .

In step 868, the controller 76 compares the sensed pressure drop across the filters 24, 26 (as determined in step 862) to the obtained threshold value. If the sensed pressure drop across the particulate filter 24 , 26 exceeds the threshold obtained, the controller 76 concludes that the filter 24 , 26 requires regeneration and the control routine 860 proceeds to step 870 . If the sensed pressure drop across the particulate filter 24 , 26 does not exceed the threshold obtained, the control routine 860 returns to step 860 to continue monitoring the buildup in the filter 24 , 26 .

In step 870, the controller 76 initiates regeneration of the filter. Specifically, the electronic controller 76 operates the fuel fired burners 20, 22 to regenerate the particulate filters 24, 26 in any of a number of ways described herein. Once filter regeneration is complete, control routine 870 ends.

The output of the pressure sensors 264 , 266 may also be used to monitor the performance of the engine 80 . Specifically, the soot build-up characteristic in the particulate filters 24, 26 may be indicative of certain engine performance characteristics. For example, excessive or otherwise abnormal soot buildup in the particulate filters 24 , 26 may indicate that the engine 80 is over-oiled. Excessive or otherwise abnormal soot buildup in the particulate filters 24 , 26 may and may indicate a stuck or leaking engine fuel injector. Electronic controller 76 may be configured to monitor and analyze the output of pressure sensors 264, 266 to determine whether any such engine conditions exist.

It should be understood that if a given design utilizes methods or devices other than pressure sensors to identify soot buildup in the particulate filters 24, 26, the output obtained by such methods or devices can be monitored or analyzed to determine whether any such engine condition. Thus, while an example embodiment of a control mode for monitoring engine performance as a function of soot buildup in the filters 24, 26 based on the output of the pressure sensors 264, 266 will be described in greater detail below, it should be understood that such The description is not intended to be limited to pressure sensor based systems only.

Referring now to FIG. 12 , a control routine 300 for monitoring engine performance as a function of soot buildup in the filters 24 , 26 is shown. The routine begins at step 302 where the electronic controller 76 determines the rate of soot accumulation in the filters 24 , 26 . Specifically, the pressure drop (ΔP) across the filters 24 , 26 is continuously monitored by the controller 76 during operation of the engine 80 . Specifically, the output of the pressure sensors 264, 266 is read at a predetermined frequency so that the pressure drop (ΔP) can be calculated and subsequently stored in a memory device (such as RAM or other storage device associated with the electronic controller 82). table. The pressure drop (ΔP) can be tracked over time. For example, a graphical representation tracking the pressure drop ([Delta]P) across one of the filters 24, 26 as a function of time is shown in FIG. In the exemplary embodiment described herein, the rate of soot accumulation can be determined by tracking the pressure drop (ΔP) over time, as shown by line 312 in the graphical representation of FIG. 13 . Once the soot accumulation rate in the soot filter 24 , 26 has been determined, the routine 300 proceeds to step 304 .

In step 304 , the electronic controller 76 analyzes the rate of soot accumulation in the particulate filters 24 , 26 . In the exemplary embodiment described herein, the controller 76 analyzes the rate of soot accumulation in the particulate filters 24 , 26 by analyzing the slope of the line 312 produced by tracking the pressure drop (ΔP) over time. For example, if the slope of line 312 remains relatively constant (i.e., within predetermined limits considered to represent a constant slope), such as indicated in dashed lines in FIG. There is no conclusion that the soot accumulation rate has changed within 26. However, if the slope of line 312 increases beyond a predetermined limit (as shown by the solid line in FIG. 13), electronic controller 76 concludes that there has been a change in the rate of soot accumulation within particulate filters 24,26. It should be understood that other methods may be utilized to analyze the rate of soot accumulation in the filters 24, 26, and the methods described here are merely exemplary in nature. Once the electronic controller 76 has analyzed the soot buildup in the particulate filters 24 , 26 , the control routine 300 proceeds to step 306 .

In step 306 , the electronic controller 76 determines whether the rate of soot accumulation within the particulate filter 24 , 26 is indicative of a predetermined engine condition. Specifically, a lookup table stored in the storage device 84 (or other storage device associated with the electronic controller 82 ) may be queried to determine whether the soot accumulation rate analyzed in step 304 meets predetermined criteria. For example, the contents of the lookup table are used to determine whether the analysis of step 304 indicates that the soot accumulation rate has not changed or has changed within predetermined tolerance limits. If so, the controller 76 concludes that the rate of soot accumulation is not indicative of engine conditions and the control routine loops back to step 302 to continue monitoring the soot accumulation in the filters 24,26. The contents of the lookup table may also be used to determine whether the analysis performed in step 304 indicates a change in the rate of soot accumulation outside predetermined limits. If so, controller 76 concludes that the soot accumulation rate may be indicative of engine condition, and control routine 300 proceeds to step 308 .

In step 308, electronic controller 76 generates an error signal. For example, electronic controller 76 may generate an output signal that causes a visual, audible, or other type of alert to be presented to an operator (eg, the driver of truck 12). This error signal may simply result in an electronic journal or the like being updated with information relevant to the filter analysis of steps 302-306.

As indicated in step 310 , the error signal may be communicated to an engine control unit (ECU) 78 associated with the engine 80 . The details of doing this are described in more detail below. However, it should be understood that such description is not limited to the transmission of an error signal generated in step 308 of control routine 300, but that any error signal described herein (together with any other error signal generated by controller 76) Can be sent to the engine control unit 78. Additionally, the engine control unit 78 may communicate information, such as engine operating information, to the controller 76 as discussed in greater detail below.

In conventional fashion, an engine system such as the engine 80 of the truck 12 includes an engine control unit which is essentially responsible for interpreting the electrical signals transmitted by the engine sensors and actuating electronically controlled engine components to control the engine. main computer. For example, the engine control unit is operable to determine the start and end of each injection cycle for each engine cylinder, or in response to conditions such as engine crankshaft position and speed (RPM), engine coolant and intake air temperature, and absolute charge boost Fuel measurement and injection timing are determined from sensed parameters such as pressure.

An error signal generated by controller 76 (or a subsequent signal generated in response to the error signal) may be communicated to engine control unit 78 . Specifically, electronic controller 76 of emission reduction assembly 10 may be configured to communicate with engine control unit 78 via interface 314 . Interface 314 may be any type of communication interface that enables electronic communication between electronic controller 76 and engine control unit 78 . One type of interface suitable for use as interface 314 is a controller area network or "CAN" interface. The CAN interface is a microcontroller serial bus network connecting devices, sensors and actuators in a system or subsystem for real-time control applications. The CAN interface was first developed by Robert Bosch GmbH in 1986. The details of the CAN interface are documented in ISO11898 (for applications up to 1 Mbit/s) and ISO11519 (for applications up to 125 Kbit/s), Both documents are hereby incorporated by reference.

Using the CAN interface 314 , information such as engine speed and turbo pressure can be obtained from the engine control unit 78 for use by the electronic controller 76 . Controller 76 may use such information in the course of executing certain control programs. By using information from the engine control unit 78, redundant sensor arrays to determine this information for the electronic controller only are eliminated.

Furthermore, the CAN interface 314 allows the transmission of error signals (eg error flags) or the like to the engine control unit 78 for use by the engine control unit 78 during its operation. For example, an error signal indicating an engine problem (as described for control process 300 ) may be communicated to engine control unit 78 . Equipped with this information, the engine control unit 78 can be programmed to perform additional engine analysis, generate an error signal to the truck operator (such as an indicator light on the truck dashboard), or store the error message in a file that can be accessed by a maintenance technician. Accessed error log. CAN interface 314 also allows the engine manufacturer to exercise a degree of control in the operation of emission reduction assembly 10 if desired.

Thus, it should be appreciated that the controller 76 of the control unit 18 monitors the operation of the fuel fired combustors 20, 22 (or other components of the emission reduction assembly 10) to determine compliance with predetermined conditions as described herein (or other status) any of them. Controller 76 may then generate a signal, such as an error signal, indicating such a condition and communicate the signal to engine control unit 78 via CAN interface 314 . Additionally, CAN interface 314 may be utilized by engine control unit 78 to communicate information, such as information related to engine operation, to controller 76 . For example, information related to engine speed or turbo boost pressure is communicated to controller 76 via CAN interface 314 . In addition to engine operating information, if so configured, launch control unit 78 may also generate and communicate control signals to controller 76 for controlling operation of fuel fired combustors 20 , 22 . For example, the engine control unit 78 may be programmed to initiate a regeneration cycle of the particulate filters 24 , 26 . In such a case, the engine control unit 78 may generate and communicate a control signal to the controller 76 causing the controller 76 to initiate regeneration of one of the particulate filters 24 , 26 .

As shown in FIG. 29 , electronic controller 76 of control unit 18 may be integrated with engine control unit 78 . Thus, engine control unit 78 controls operation of emission reduction assembly 10 in addition to controlling operation of engine 80 . In this way, the engine control unit 78 is also essentially the host computer responsible for interpreting the electrical signals sent by the sensors associated with the emission reduction assembly 10 and for actuating the electronically controlled components associated with the emission reduction assembly 10 . For example, the engine control unit 78 is operable to determine the start and end of each regeneration cycle, determine the amount and fuel-to-air ratio of fuel to air introduced to the fuel-fired combustors 20, 22, and the exhaust Other functions implemented by the controller 76 of the reduction assembly 10 .

As such, the engine control unit 78 includes a plurality of electronic components that are collectively associated with the electronic unit used in the control of the engine system. For example, the electronic control unit 78 may include a processor such as a microprocessor 728 and a storage device 730 such as a programmable read-only memory device (PROM), including an erasable PROM (EPROM or EEPROM).

Storage device 730 is provided for storing instructions, eg, in the form of a software program (or programs), which, when executed by the processor, enable engine controller 78 to control the operation of both engine 80 and emission reduction assembly 10 . As such, the engine control unit 78 is electrically coupled to both the engine 80 and the emission reduction assembly 10 as shown in FIG. 29 . Specifically, engine control unit 78 is electrically coupled to engine 80 via signal line 718 , and engine control unit 78 is electrically coupled to emission reduction assembly 10 via signal line 720 . Although the signal lines 718, 720 are each schematically shown as a single line, it should be understood that the signal lines 718, 720 may be configured as any type of connection that permits communication between the engine control unit 78 and the engine 80 or emission reduction assembly 10, respectively. A signal-carrying component that transmits electrical signals in one or two directions. For example, either or both signal lines 718, 720 may be implemented as a wire harness having multiple signal lines that carry electrical signals between the engine control unit 78 and the engine 80 or the emission reduction assembly 10, respectively. In such an arrangement, signals generated by operation of a plurality of engine sensors 734 or 736 associated with emission reduction assembly 10 are passed to engine control unit 78 via corresponding wiring harnesses, while signals generated by engine control unit 78 are passed through corresponding The wiring harness is passed to the engine 80 or the emission reduction assembly 10 . It should be understood that any number of other wiring configurations may be used. For example, for the design of either or both of the signal lines 718, 720, separate signal lines for each may be used or a system utilizing signal multiplexers may be used. Additionally, signal lines 718 , 720 may be integrated to electrically couple engine 80 and emission reduction assembly 10 to engine control unit 78 using a single wiring harness or system.

The engine control unit 78 also includes an analog interface circuit 732 . Analog interface circuitry 732 converts output signals from respective analog engine sensors 734 and emission reduction sensors 736 into signals suitable for presentation to the input of microprocessor 728 . Specifically, the analog interface circuit 732 converts the analog signals generated by the sensors 734 and 736 into digital signals used by the microprocessor 728 by using an analog-to-digital (A/D) converter (not shown) or the like. It should be understood that the A/D converter may be implemented as a discrete device or devices, or may be integrated into the microprocessor 728 . It should also be understood that the analog interface circuit 732 may be bypassed if any one or more of the sensors 734, 736 produces a digital output signal.

It should be appreciated that the emission reduction sensor 736 in communication with the engine control unit 78 may be any of the sensors described herein with respect to the emission reduction assembly 10 . For example, pressure sensors 264 , 266 and temperature sensors 182 , 184 , 186 associated with soot reduction assemblies 14 , 16 may be coupled to engine control unit 78 . Additionally, the sensors and detectors 164 , 426 , 460 , 510 of the control unit 18 may be coupled to the engine control unit 78 .

Analog interface circuit 732 also converts signals from microprocessor 728 into output signals suitable for presentation to electrically controlled components 744 associated with engine 80 and electronically controlled components 746 associated with emission reduction assembly 10 . Specifically, the analog interface circuit 732 converts the digital signal generated by the microprocessor 728 by utilizing a digital-to-analog (D/A) converter (not shown) or the like into: Assemblies, fan assemblies, etc., are used by electrically controlled components 744 associated with the engine, and by components such as the pump motor 92, air valve 102, fuel injectors 132, 134, valves 140, 154, 156, and igniters 170, 172 etc. analog signals used by electronically controlled components 746 associated with emission reduction assembly 10 . It should be understood that, similar to the A/D converter described above, the D/A converter may be implemented as a discrete device or devices, or may be integrated into the microprocessor 728 . It should be appreciated that if any one or more of electronically controlled components 744 associated with engine 80 and electronically controlled components 746 associated with emission reduction assembly 10 operate on analog input signals, the analog interface circuitry may be bypassed 732.

Accordingly, the engine control unit 78 is operable to control the operation of both the engine 80 and the emission reduction assembly 10 . Specifically, the engine control unit 78 operates in a closed-loop control mode, in which configuration the engine control unit 78 monitors the outputs of the sensors 734, 736 to control inputs to the controlled components 744, 746 to manage the engine 80 and emissions Reduce the operation of component 10. Specifically, engine control unit 78 communicates with sensors 734 to determine engine coolant temperature therein, manifold air pressure, crankshaft/flywheel position and speed, and the amount of oxygen in the exhaust. Equipped with this data, the engine control unit 78 performs many calculations per second, including looking up values in pre-programmed tables, in order to execute programs to perform functions such as changing the ignition timing or determining how much fuel injectors remain open in a particular cylinder. long time.

Simultaneously with such control of the engine 80 , the engine control unit 78 also executes a program for controlling the operation of the emission reduction assembly 10 . Specifically, the engine control unit 78 is in communication with the sensor 736 for determining the level of soot accumulation in the particulate filter therein, as well as various temperature and pressure readings, among other things. Equipped with this data, the engine control unit 78 performs many calculations per second, including look-ups of values in pre-programmed tables, in order to execute algorithms to perform the functions of supplying fuel and air to the fuel-fired combustors 20, 22, using Electrodes 48, 50 are energized, etc.

Thus, the engine control unit 78 controls the operation of both the engine 80 and the emission reduction assembly 10 . Specifically, during operation of engine 80, engine control unit 78 executes a fuel injector control program that generates injection signals in the form of a number of injection pulses that are communicated to individual injectors of the engine's fuel injector assembly. The fuel injectors are opened for a predetermined period of time in response to receiving an injection pulse, thereby injecting fuel into corresponding cylinders of the engine 80 . Simultaneously with the execution of the fuel injection routine, the engine control unit 78 executes the burner control routine which generates a number of control signals which are communicated to the various electronically controlled components 746 associated with the emission reduction assembly 10 to control the fuel combustion Operation of the burners 20,22. For example, signals are generated and communicated for changing the amount of fuel supplied to the fuel fired burners 20, 22, energizing the electrodes 48, 50, and the like.

Additionally, engine control unit 78 monitors inputs from various sensors 736 associated with emissions reduction assembly 10 for utilization in closed loop control of assembly 10 . For example, signals to the engine control unit 78 are utilized to monitor the temperature of specific regions within the soot reduction assemblies 14, 16, the pressure drop across the particulate filters 24, 26, and many other functions described herein.

It should be understood that such programs (ie, the fuel injector control program and the fuel reformer control program) may be implemented as separate software programs or may be combined into a single software program.

Referring now to FIG. 14 , a control routine 350 for monitoring ash accumulation in the particulate filters 24 , 26 is shown. As multiple filter regenerations occur, ash builds up in the particulate filters 24, 26 over time. By monitoring (eg, measuring and data logging) the pressure drop (ΔΡ) across the particulate filter 24, 26 after each filter regeneration process, it can be determined when the filter needs to be de-ashed. Specifically, shortly after each filter regeneration cycle, the pressure drop (ΔP) across the particulate filters 24, 26 is obtained and stored in memory, as described in more detail herein. As soon as the pressure drop across the particulate filter 24, 26 exceeds a predetermined upper limit, an error signal is generated indicating that the filter needs to be maintained by removing soot from the filter.

The control routine 350 begins with step 352 where the electronic controller 76 regenerates one of the particulate filters 24 , 26 . Specifically, the electronic controller 76 operates the fuel fired burners 20 , 22 to generate heat to regenerate the particulate filters 24 , 26 as described in greater detail herein. Once the regeneration cycle is complete, control routine 350 proceeds to step 354 .

In step 354 , the electronic controller 76 measures the pressure drop (ΔP) across the most recently regenerated particulate filter 24 , 26 . Specifically, the output of the pressure sensor 264, 266 of the most recently regenerated filter is read so that the pressure drop (ΔP) can be calculated.

Thereafter, control proceeds to step 356 where the pressure drop (ΔP) value across the most recently regenerated particulate filter 24, 26 is stored in a memory device (such as RAM or other memory associated with the electronic controller 82). device) table. Control program 350 then proceeds to step 358 .

In step 358, the electronic controller 76 determines whether the pressure drop (ΔP) across the most recently regenerated particulate filter 24, 26 is above a predetermined upper limit. If the pressure drop (ΔP) across the most recently regenerated particulate filter 24, 26 is below the upper limit, the control routine 350 ends until restarted after the next filter regeneration cycle is complete. However, if the pressure drop (ΔP) across the most recently regenerated particulate filter 24 , 26 is above the upper control limit, control routine 350 proceeds to step 360 .

In step 360, electronic controller 76 generates an error signal. For example, electronic controller 76 may generate an output signal that causes a visual, audible, or other type of alert to be presented to an operator (eg, the driver of truck 12). Alternatively, the error signal may simply result in an electronic journal or the like being updated with information relevant to the filter analysis of steps 352-358. It should be understood that the error signal generated in step 360 may be configured for use with any type of warning or error tracking device to meet the requirements of a given system design.

As indicated in step 362 , if the electronic controller 76 is so equipped, the error signal (or a subsequent signal generated in response to the error signal) may be communicated to the engine control unit 78 via the CAN interface 314 . Equipped with this information, the engine control unit 78 can be programmed to perform additional filter analysis, generate an error signal to the truck operator indicating that the affected filter 24, 26 requires maintenance (i.e., dust removal) (e.g. indicator on the panel), or store the error message in an error log that can be accessed by a maintenance technician. The control routine 350 is then ended.

As noted above, the electronic controller 76 may use a number of different control modes to determine when one of the particulate filters 24, 26 requires regeneration. For example, a sensor-based approach or a timing-based approach may be utilized. In either case, when the controller 76 determines that one of the particulate filters 24, 26 requires regeneration, a regeneration cycle is initiated wherein the electronic controller 76 operates the fuel-fired burners 14, 16, respectively, to regenerate the filters 24, 26 . To this end, the air pump 90 and air valve 102 are operated to supply combustion air to the appropriate burners 20 , 22 . Simultaneously, fuel is supplied to the appropriate combustors 20 , 22 via the fuel delivery assembly 120 . Specifically, to supply fuel to the fuel-fired combustor 20 , the fuel injector 132 is operated to inject fuel into the mixing chamber 146 where the fuel is in the flow of atomizing air supplied to the mixing chamber 146 through the air valves 154 , 156 . Medium atomization. The resulting air/fuel mixture is directed via fuel line 148 to fuel inlet nozzle 54 of fuel-fired combustor 20 . On the other hand, to supply fuel to the fuel-fired combustor 22, the fuel injector 134 is operated to inject fuel into the mixing chamber 146 where the fuel is in the flow of atomizing air supplied to the mixing chamber 146 through the air valves 154, 156. Medium atomization. The resulting air/fuel mixture is directed via fuel line 150 to fuel inlet nozzle 54 of fuel-fired combustor 22 .

The air/fuel mixture entering the combustors 20 , 22 via the fuel inlet nozzle 54 is ignited by the electrodes 48 , 50 . In the case of operating the fuel-fired burner 20 , actuation of the igniter 170 creates a spark across the gap 52 between the electrodes 48 , 50 of the fuel-fired burner 20 , thereby igniting the air/fuel exiting the fuel inlet nozzle 54 mixture. In the case of operating the fuel-fired burner 22 , actuation of the igniter 172 creates a spark across the gap 52 between the electrodes 48 , 50 of the fuel-fired burner 22 , thereby igniting the air/fuel exiting the fuel inlet nozzle 54 mixture.

As noted above, the electronic controller 76 monitors the output of the flame temperature sensor 182 to detect or otherwise determine the presence of an ignition flame in the combustion chamber 34 of the actuated fuel fired burner 20 , 22 . Specifically, when the electronic controller 76 initiates ignition of the fuel-fired burners 20, 22, the controller 76 monitors the output of the flame temperature sensor 182 to ensure that the air/fuel mixture entering the burners 20, 22 , 50 sparks ignited. An error signal is generated if the output of the flame temperature sensor does not meet predetermined criteria.

Once the fuel fired burners 20, 22 are activated, they begin to generate heat. Such heat is directed downstream (relative to the flow of exhaust) and into contact with the upstream faces of the particulate filters 24 , 26 . This heat ignites and burns the soot particles collected in the filter base 60 , regenerating the particulate filters 24 , 26 . For example, heat in the range of 600-650 degrees Celsius may be sufficient to regenerate an uncatalyzed filter, while heat in the range of 300-350 degrees Celsius may be sufficient to regenerate a catalyzed filter.

In an exemplary embodiment, regeneration of the particulate filters 24, 26 may take only a few minutes. Furthermore, it should be understood that regeneration of the particulate filters 24, 26 may be self-sustaining once initiated by heat from the fuel fired burners 24, 26, respectively. Specifically, once the filters 24, 26 are heated to a temperature at which the soot particles trapped therein begin to ignite, ignition of the initial portion of the soot particles trapped therein can cause the remaining soot particles to ignite—in a manner that is largely In the same way that a cigar burns slowly from one end to the other. Essentially, when the soot particles "burn", a certain amount of heat is released in the "burn zone". Locally, the soot layer (in the combustion zone) is now much hotter than the immediate surround. Heat is thus transferred to the soot layer downstream of the not yet ignited combustion zone. The energy delivered may be sufficient to initiate an oxidation reaction that brings the unignited soot to a temperature above its ignition temperature. As such, heat from the fuel-fired burners 20, 22 may only be needed to initiate the regeneration process of the filter 24 (ie, initiate the ignition process of the soot trapped therein).

During the regeneration cycle, the fuel fired burners 20, 22 may be controlled in the manner described herein with respect to FIGS. 9-11. Specifically, the control processes 200 and 250 may be utilized to monitor the temperature in the soot reduction assemblies 14, 16 in the manner described herein.

Referring now to FIGS. 30 and 31 , a control routine 750 for activating the fuel fired combustors 20 , 22 at the beginning of a regeneration cycle is shown. The routine begins at step 752 where the routine determines whether a request to start a fuel-fired burner 20, 22 has been executed (ie, a burner start request). It should be appreciated that the burner activation request may take many different forms, including, for example, by a software control program generating the activation request in response to a sensed, timed, or otherwise determined indication that one of the particulate filters 24, 26 requires regeneration. . For example, a sensor-based, map-based, or timing-based approach may be utilized to generate the activation request. Thus, in step 752 , if control routine 750 detects a burner start request, a control signal is generated and routine 750 proceeds to step 754 . If the control routine 750 does not detect a burner start request, the routine 750 loops back to step 752 to continue monitoring for such requests.

In step 754 , the electronic controller 76 supplies a relatively high amount of fuel to the fuel fired burners 20 , 22 to facilitate ignition of the flame in the combustion chamber 34 . Specifically, the air/fuel mixture is supplied to the burners 20 , 22 where it is ignited by a spark between the electrodes 48 , 50 in the presence of combustion air supplied by the control unit 18 . This initial fueling level is shown graphically by arrow 764 in FIG. 31 . Control program 750 then proceeds to step 756 .

In step 756, the controller 76 determines whether ignition has occurred. Controller 76 can do this in any of a variety of ways. For example, the electronic controller 76 may monitor the output of the flame temperature sensor 182 to detect or otherwise determine the presence of an ignition flame in the combustion chamber 34 of the fuel fired burner 20 , 22 . Specifically, when electronic controller 76 initiates ignition of fuel-fired burners 20, 22, controller 76 may monitor the output of flame temperature sensor 182 to ensure that the air/fuel mixture entering 48, 50 sparks ignited. Once ignition has been detected, control routine 750 proceeds to step 758 . The ignition detection diagram is shown at point 766 in FIG. 31 .

In step 758 , the electronic controller 76 reduces the fuel supplied to the fuel fired burners 20 , 22 . In this manner, electronic controller 76 increases the air-to-fuel ratio of the air/fuel mixture supplied to combustors 20 , 22 by reducing the amount of fuel injected by fuel injectors 132 , 134 into mixing chamber 146 . For example, to reduce the fuel supplied to fuel-fired burner 20, electronic controller 76 generates a control signal on signal line 136 for reducing the amount of fuel injected by fuel injector 132 into mixing chamber 146, thereby increasing the amount of fuel via Fuel line 148 supplies the air to fuel ratio of the air/fuel mixture to fuel fired combustor 20 . Similarly, to reduce the fuel supplied to fuel-fired burner 22, electronic controller 76 generates a control signal on signal line 138 for reducing the amount of fuel injected by fuel injector 134 into mixing chamber 146, thereby increasing The air to fuel ratio of the air/fuel mixture supplied to the fuel fired combustor 22 via the fuel line 150 .

The electronic controller 76 operates the fuel fired burners 20 , 22 at this reduced fuel level for a period of time to preheat the components of the soot reduction assemblies 14 , 16 . Such a warm-up period may be time-based (ie, last for a predetermined period of time) or may be sensor-based (ie, last until one or more of the temperature sensors 182 , 184 , 186 senses a predetermined temperature). This warm-up period is shown schematically by arrow 768 in FIG. 31 . Once the time period has elapsed (ie, once the system has warmed up), control routine 750 proceeds to step 760 .

In step 760 , the electronic controller 76 ramps or otherwise increases the fuel supplied to the fuel fired burners 20 , 22 . To this end, electronic controller 76 reduces the air to fuel ratio of the air/fuel mixture supplied to combustors 20 , 22 by increasing the amount of fuel injected by fuel injectors 132 , 134 into mixing chamber 146 . For example, to increase the fuel supplied to fuel-fired burner 20, electronic controller 76 generates a control signal on signal line 136 for increasing the amount of fuel injected by fuel injector 132 into mixing chamber 146, thereby reducing Fuel line 148 supplies the air to fuel ratio of the air/fuel mixture to combustor 20 . Similarly, to increase the fuel supplied to fuel-fired burner 22, electronic controller 76 generates a control signal on signal line 138 for increasing the amount of fuel injected by fuel injector 134 into mixing chamber 146, thereby reducing The air to fuel ratio of the air/fuel mixture supplied to combustor 22 via fuel line 150 .

In step 760, the fuel supplied to the fuel fired burners 20, 22 may be increased at a predetermined slope. For example, as illustrated graphically by arrow 770 of FIG. 31 , the fuel level may gradually increase at a predetermined slope to a particular predetermined fuel level, as indicated by point 772 of FIG. 31 . Such predetermined fuel levels may correspond to desired regeneration temperatures. Once the fuel level has been ramped up, control routine 750 proceeds to step 762 .

In step 762, the controller 76 adjusts the fuel level supplied to the fuel fired burners 20, 22 for filter regeneration. Specifically, during the filter regeneration cycle, the fuel supply to the burners 20, 22 is regulated by closed-loop control, as described above with respect to Figures 9 and 10 . Such closed loop regulation of the fuel supply to the combustors 20 , 22 is generally shown in the region indicated by arrow 418 in FIG. 31 . Once under closed loop control, the startup control routine 750 ends.

Referring now to FIG. 32 , another start-up control routine 780 for starting the fuel-fired combustors 20 , 22 at the beginning of a regeneration cycle is shown. The routine begins at step 782 where the routine 780 determines whether a request to start a fuel fired burner 20, 22 has been executed (ie, a burner start request). It should be appreciated that the combustor activation request may take many different forms, including, for example, generating the activation request by a software control program in response to a sensed, timed, or otherwise determined indication that one of the particulate filters 24, 26 requires regeneration. For example, a sensor-based, map-based, or timing-based approach may be utilized to generate the activation request. Thus, in step 782 , if control routine 780 detects a burner start request, a control signal is generated and routine 780 proceeds to step 784 . If the control routine 780 does not detect a burner start request, the routine 780 loops back to step 782 to continue monitoring for such requests.

In step 784, the controller 76 energizes the electrode assembly of the fuel-fired combustor 20, 22 to be regenerated prior to fuel being supplied to the combustor. Specifically, during start-up of the fuel-fired burner 20 , the controller 76 operates the igniter 170 to begin generating a spark between the electrodes 48 , 50 of the burner 20 before fuel is supplied to the burner 20 . In the case of starting the fuel-fired burner 22 , the electronic controller 76 operates the igniter 172 to initiate a spark between the electrodes 48 , 50 of the burner 22 before fuel is supplied to the burner 22 .

The controller 76 continues to energize the electrode assemblies of the fuel fired burners 20, 22 for a predetermined period of time before fuel is introduced into the burners. The duration of such time periods can be configured to meet the needs of a given system design. In particular, it has been found that energizing the electrode assembly for a predetermined period of time prior to fuel introduction cleans the fouling surfaces on the electrodes 48, 50 (ie, removes soot or other matter accumulated thereon). Thus, any material that accumulates on the electrodes 48, 50 (eg, soot, diesel fuel, water, oil, etc.) can be removed from the electrodes prior to fuel introduction, thereby enhancing the operation of the fuel-fired combustors 20, 22. Once the predetermined period of time has elapsed, control routine 780 proceeds to step 786 .

In step 786, electronic controller 76 supplies fuel and air to fuel fired burners 20, 22 for regenerating particulate filters 24, 26 in the manner described above. Specifically, the air/fuel mixture is supplied to the fuel fired burners 20 , 22 where it is ignited by a spark between the electrodes 48 , 50 in the presence of combustion air supplied by the control unit 18 . The heat generated by the combustion of the fuel regenerates the particulate filters 24 , 26 .

It should be understood that the control programs 750, 780 may be combined if desired. For example, the electrode assembly may be energized for a period of time (as described in step 784 of control routine 780 ) prior to introducing fuel for ignition (as described in step 754 of control routine 750 ).

Referring now to FIGS. 15 and 16 , a control routine 400 for shutting down the fuel fired combustors 20 , 22 during a regeneration cycle is shown. The control routine begins at step 402 where the electronic controller 76 supplies fuel and air to the fuel fired burners 20, 22 for regenerating the particulate filters 24, 26 in the manner described above. Specifically, the air/fuel mixture is supplied to the fuel fired burners 20 , 22 where it is ignited by a spark between the electrodes 48 , 50 in the presence of combustion air supplied by the control unit 18 . As described with respect to Figures 9 and 10, during such a filter regeneration cycle, the fuel supply to the burners 20, 22 is regulated by closed loop control. Such closed-loop regulation of the fuel supply to the combustors 20 , 22 is generally shown in the region indicated by arrow 418 in FIG. 16 .

During the filter regeneration cycle, the control routine 400 determines at step 404 whether a request to shut down the fuel fired burner 20 , 22 has been executed (ie, a burner shutdown request). It should be appreciated that the burner shutdown request may take many different forms, including, for example, in response to a sensed, timed, or otherwise determined particulate filter 20, 22 has regenerated or that filter regeneration is self-sustaining (as described above). Instead, a shutdown request generated by a software control program, an automatic shutdown request generated by a software control program or the like, a timed shutdown request, or any other manual, software or hardware driven shutdown request. In particular embodiments, the burner off request may be generated in response to an ignition key associated with the engine 80 of the truck 12 being adjusted from the on position to the off position. Thus, in step 404 , if control routine 400 detects a burner shutdown request, a control signal is generated and routine 400 proceeds to step 406 . A detection diagram of a shutdown request is shown at point 420 of FIG. 16 . If the control routine 400 does not detect a burner shutdown request, the routine 400 loops back to step 402 to continue the filter regeneration cycle.

In step 406 , the electronic controller 76 reduces the fuel supplied to the fuel fired burners 20 , 22 . To this end, electronic controller 76 increases the air to fuel ratio of the air/fuel mixture supplied to combustors 20 , 22 by reducing the amount of fuel injected by fuel injectors 132 , 134 into mixing chamber 146 . For example, to reduce the fuel supplied to fuel-fired burner 20, electronic controller 76 generates a control signal on signal line 136 for reducing the amount of fuel injected by fuel injector 132 into mixing chamber 146, thereby increasing the amount of fuel via Fuel line 148 supplies the air to fuel ratio of the air/fuel mixture to combustor 20 . Similarly, to reduce the fuel supplied to fuel-fired burner 22, electronic controller 76 generates a control signal on signal line 138 for reducing the amount of fuel injected by fuel injector 134 into mixing chamber 146, thereby increasing The air to fuel ratio of the air/fuel mixture supplied to the fuel fired combustor 22 via the fuel line 150 .

The electronic controller 76 operates the fuel fired burners 20, 22 at this reduced fuel level for a predetermined period of time. Such a period of time is shown diagrammatically by arrow 422 in FIG. 16 . Once the predetermined period of time has elapsed, control proceeds to step 408 .

In step 408, the fuel supply to the combustors 20, 22 is cut off. Specifically, electronic controller 76 deactivates fuel delivery assembly 120 , thereby stopping fuel supply to combustors 20 , 22 . To shut off fuel supply to fuel-fired burner 20 , electronic controller 76 closes fuel actuation valve 140 and ceases to generate a control signal on signal line 136 , thereby causing fuel injector 132 to cease injecting fuel into mixing chamber 146 . Once the fuel held in fuel line 148 is consumed by combustor 20 , no additional fuel enters fuel inlet nozzle 54 of combustor 20 . Similarly, to shut off the fuel supply to the fuel-fired burner 22, the electronic controller 76 closes the fuel activation valve 140 and stops generating the control signal on the signal line 138, thereby causing the fuel injector 134 to stop injecting into the mixing chamber 146. fuel. Once the fuel held in the fuel line 150 is consumed by the combustor 22 , no additional fuel enters the fuel inlet nozzle 54 of the combustor 22 .

In step 408 , electronic controller 76 maintains supply of combustion air and atomizing air to burners 20 , 22 and also maintains operation of igniters 170 , 172 . Specifically, with the fuel-fired burner 20 turned off, the electronic controller 76 continues to supply combustion air to the burner 20 via the air line 58 and continues to supply combustion air via the fuel line 148 even though fuel is no longer being supplied to the burner 20 . Supply atomizing air. Controller 76 continues to operate igniter 170 to continue generating a spark in combustion chamber 34 of combustor 20 . With the fuel-fired burner 22 turned off, the electronic controller 76 continues to supply combustion air to the burner 22 via the air line 58 and atomization air via the fuel line 150 even though fuel is no longer being supplied to the burner 22. Air. Controller 76 continues to operate igniter 172 to continue generating a spark in combustion chamber 34 of combustor 22 . Such continuous air supply and spark generation ensures that the remaining fuel in the system is combusted by the combustors 20, 22, thereby reducing, if not eliminating, emissions of unburned hydrocarbons.

The electronic controller 76 continues to supply combustion air and atomizing air and operate the igniter for a predetermined period of time as described above. Such a period of time is shown diagrammatically by arrow 424 in FIG. 16 . Once the predetermined period of time has elapsed, control proceeds to step 410 .

In step 410 , electronic controller 76 shuts off combustion air flow to fuel fired burners 20 , 22 . Specifically, electronic controller 76 stops operation of motor 92 , thereby stopping operation of air pump 90 . After turning off the air pump 90, the electronic controller 76 continues to supply atomizing air and to operate the igniter as described above for a predetermined period of time. Once the predetermined period of time has elapsed, control proceeds to step 412 .

In step 412 , the electronic controller 76 shuts off the flow of atomizing air to the fuel fired burners 20 , 22 . Specifically, electronic controller 76 closes atomizing air valve 156 , thereby reducing air flow to mixing chamber 146 and burners 20 , 22 . It is noted that the clean air valve 154 remains open whereby the reduced flow of clean air continues into the mixing chamber 146 and from there to the fuel fired burners 20 , 22 . As noted above, a flow of clean air from clean air valve 154 is typically supplied constantly to mixing chamber 146 during operation of engine 80 of truck 12 to prevent residue (eg, black smoke) Accumulation in fuel inlet nozzle 54 of 20 , 22 .

In step 412 , the electronic controller 76 stops the generation of the spark within the combustion chamber 34 of the fuel fired burner 20 , 22 . Specifically, electronic controller 76 stops the operation of igniter 170 (in the case of burner 20) and igniter 172 (in the case of burner 172), thereby stopping the electrode 48 in the case of fuel-fired burners 20,22. , 50 sparks are generated between the electrode gaps 52 . Then, the control routine 400 ends.

As noted above, during execution of the shutdown control routine 400 (among other times as well), there are instances where the electronic controller 76 supplies combustion air to one of the fuel fired burners 20, 22 but not fuel to either. Also as described above, electric motor 92 drives both fuel pump 122 and air pump 90 . Therefore, when the motor 92 drives the air pump 90 to supply combustion air, the fuel pump 122 is also driven. Fuel pumped by the fuel pump 122 is returned to the truck fuel tank 124 via the fuel return line 142 during situations where the electronic controller 76 is supplying combustion air to the fuel-fired burners 20 , 22 but not fuel to either. As shown in FIG. 8 , fuel pressure sensor 426 senses fuel pressure in fuel return line 142 . The output of fuel pressure sensor 426 is communicated to electronic controller 76 via signal line 428 . If fuel return line 142 is constrained such that fuel cannot easily flow back into fuel tank 124 , pressure on the seals of fuel pump 122 may increase, which may require repair or replacement of pump 122 .

As shown in FIG. 17 , the electronic controller 76 executes a control process 450 to monitor the return fuel line 142 . The control routine 450 begins with step 452 where the electronic controller 76 determines the fuel pressure in the fuel return line 142 . Specifically, electronic controller 76 scans or reads signal line 428 for output from fuel pressure sensor 426 . Then, the control program 450 proceeds to step 454 .

In step 454 , the electronic controller 76 determines whether the sensed fuel pressure is above a predetermined upper pressure limit. If the fuel pressure is below the upper pressure limit, the control routine 450 loops back to step 452 to continue monitoring the output of the fuel pressure sensor 426 . However, if the fuel pressure is above the upper control limit, control routine 450 proceeds to step 456 .

In step 456 , electronic controller 76 turns off components associated with control unit 18 . Specifically, since the electronic controller 76 concludes in step 454 that the fuel pressure in the fuel return line 142 is higher than the upper control limit, the controller 76 stops the operation of the drive motor 92, thereby stopping the operation of the fuel pump 122 . Control program 450 then proceeds to step 458 .

In step 458, electronic controller 76 generates an error signal. For example, electronic controller 76 may generate an output signal that causes a visual, audible, or other type of alert to be presented to an operator (eg, the driver of truck 12). Alternatively, the error signal may simply result in an electronic logbook or the like being updated with information related to the fuel pressure analysis of steps 452-456. It should be understood that the error signal generated in step 458 may be configured for use with any type of warning or error tracking device to meet the requirements of a given system design. Additionally, the error signal (or a subsequent signal generated in response to the error signal) may be communicated to the engine control unit 78 via the CAN interface 314 if so equipped at the electronic controller 76 . Equipped with this information, the engine control unit 78 can be programmed to perform additional analysis, generate an error signal to the truck operator indicating that the control unit 18 has shut down (eg, an indicator on the truck dashboard lights up), or send an error message Stored in an error log that can be accessed by maintenance technicians. The control routine 450 then ends.

Referring again to FIG. 8 , the control unit 18 may be equipped with one or more sensors for detecting the presence of predetermined environmental conditions within the interior chamber 112 of the control housing 72 . For example, the control unit 18 may be configured to include a smoke detector 460 . The output of smoke detector 460 is communicated to electronic controller 76 via signal line 462 . As described in greater detail herein, the soot detector 460 may be used to detect the presence of fuel particles or soot in the interior chamber 112 of the control housing 72 . If the presence of fuel particles or soot is detected, the system can be shut down and an error signal generated. Smoke detector 460 may be implemented as any type of smoke detector. In the exemplary embodiment of the control unit 18 described herein, the smoke detector 460 is implemented as a non-ionizing type smoke detector, such as a commercially available IR detector.

As shown in FIG. 18 , the electronic controller 76 executes a control routine 500 to monitor the interior chamber 112 of the control housing 72 for the presence of fuel particles or soot. Control routine 500 begins with step 502 where electronic controller 76 scans or reads signal line 462 to obtain output from smoke detector 460 . Once the controller 76 has obtained the output from the smoke detector 460 , the control routine 500 proceeds to step 504 .

In step 504 , electronic controller 76 determines whether the output of smoke detector 460 indicates the presence of fuel particles or soot in interior chamber 112 of control housing 72 . If the output of the smoke detector 460 does not indicate the presence of fuel particles or soot in the interior chamber 112 of the control housing 72 , the control routine 500 loops back to step 502 to continue monitoring the output of the detector 460 . However, if the output of the smoke detector 460 indicates the presence of fuel particles or soot in the interior chamber 112 of the control housing 72 , a control signal is generated and the control routine 500 proceeds to step 506 .

In step 506 , electronic controller 76 turns off components associated with control unit 18 . Specifically, since the electronic controller 76 concluded in step 454 that the output of the smoke detector 460 indicated the presence of fuel particles or soot in the interior chamber 112 of the control housing 72, the controller 76 ceases operation of the drive motor 92 , thereby stopping the operations of the fuel pump 122 and the air pump 90 . Control routine 500 then proceeds to step 508 .

In step 508, electronic controller 76 generates an error signal. For example, electronic controller 76 may generate an output signal that causes a visual, audible, or other type of alert to be presented to an operator (eg, the driver of truck 12). Alternatively, the error signal may simply result in an electronic journal or the like being updated with information relevant to the analysis of steps 502 and 504 . It should be understood that the error signal generated in step 508 may be configured for use with any type of warning or error tracking device to meet the requirements of a given system design. Additionally, the error signal (or a subsequent signal generated in response to the error signal) may be communicated to the engine control unit 78 via the CAN interface 314 if so equipped at the electronic controller 76 . Equipped with this information, the engine control unit 78 can be programmed to perform additional analysis, generate an error signal to the truck operator indicating that the control unit 18 has shut down (eg, an indicator on the truck dashboard lights up), or send an error message Stored in an error log that can be accessed by maintenance technicians. Control routine 500 then ends.

As shown in FIG. 8 , the control unit 18 may be equipped with one or more sensors for detecting the presence of predetermined environmental conditions in the interior chamber 112 of the control housing 72 . For example, the control unit may be configured to include a temperature sensor 510 . The output of temperature sensor 510 is communicated to electronic controller 76 via signal line 512 . As described in more detail below, a temperature sensor 510 may be used to detect the temperature in the interior chamber 112 of the control housing 72 . If the temperature in the interior chamber 112 of the control housing 72 exceeds a predetermined upper temperature limit (eg, 125 degrees Celsius), the system may shut down and an error signal may be generated. Temperature sensor 510 may be implemented as any type of electronic temperature sensor. In the exemplary embodiment of the control unit 18 described here, the temperature sensor 510 is implemented, for example, as a commercially available thermocouple.

As shown in FIG. 19 , the electronic controller 76 executes a control program 550 to monitor the temperature in the interior chamber 112 of the control housing 72 . Control routine 550 begins with step 552 where electronic controller 76 scans or reads signal line 512 to obtain an output from temperature sensor 510 . Once the controller 76 has obtained an output from the temperature sensor 510 , the control routine 550 proceeds to step 554 .

In step 554, electronic controller 76 determines whether the sensed temperature in interior chamber 112 of control housing 72 is above a predetermined upper temperature limit (eg, 125 degrees Celsius). If the temperature in the interior chamber 112 of the control housing 72 is below the upper temperature limit, the control routine 550 loops back to step 552 to continue monitoring the output of the temperature sensor 510 . However, if the temperature in the interior chamber 112 of the control housing 72 is above the upper control limit, a control signal is generated and the control routine 550 proceeds to step 556 .

In step 556 , electronic controller 76 turns off components associated with control unit 18 . Specifically, since the electronic controller 76 concludes in step 554 that the temperature in the interior chamber 112 of the control housing 72 is above the upper control limit, the controller 76 stops operation of the drive motor 92, thereby stopping the fuel pump 122 and the operation of the air pump 90. Control program 550 then proceeds to step 558 .

In step 558, electronic controller 76 generates an error signal. For example, electronic controller 76 may generate an output signal that causes a visual, audible, or other type of alert to be presented to an operator (eg, the driver of truck 12). Alternatively, the error signal may simply result in an electronic logbook or the like being updated with information related to the temperature analysis of steps 552 and 554 . It should be understood that the error signal generated in step 558 may be configured for use with any type of warning or error tracking device to meet the requirements of a given system design. Furthermore, if the electronic controller 76 is so equipped, the error signal (or a subsequent signal generated in response to the error signal) may be communicated to the engine control unit 78 via the CAN interface 314 . Equipped with this information, the engine control unit 78 can be programmed to perform additional analysis, generate an error signal to the truck operator indicating that the control unit 18 has shut down (eg, an indicator on the truck dashboard lights up), or send an error message Stored in an error log that can be accessed by maintenance technicians. The control routine 550 then ends.

Referring now to FIG. 20 , an emission reduction assembly 600 is shown. Emissions reduction assembly 600 includes a number of components common to emission reduction assembly 10 . Common parts between the two assemblies are designated by common reference numerals.

Emissions reduction assembly 600 includes controller 76 , a fuel supply unit such as fuel pump 122 under the control of controller 76 , and fuel fired burner 606 . The assembly 600 may be mounted in the truck 12 horizontally, vertically, or upside down. A diesel oxidation catalyst 608 may optionally be positioned upstream of the filter base 60 as shown in FIG. 20 . A diesel oxidation catalyst 608 (or any other form of oxidation catalyst) may be used to oxidize any unburned hydrocarbons or carbon monoxide (CO), thereby generating additional heat that is transferred downstream to the filter base 60 . Alternatively, as shown in FIG. 21 , emission reduction assembly 600 may be configured without diesel oxidation catalyst 608 .

As noted above, the filter substrate 60 may be impregnated with a catalytic material, such as, for example, a noble metal catalytic material. For example, the catalytic material can be implemented in platinum, rhodium, palladium, including combinations thereof, and any other similar catalytic material. The use of catalytic materials reduces the temperature required to ignite the collected soot particles.

Unlike assembly 10 , in the exemplary embodiment described herein, emission reduction assembly 600 does not utilize supplemental air pumped from an air pump, such as air pump 90 . The combustion process is thus supported by the oxygen in the exhaust gas.

The fuel fired burner 606 is shown in more detail in FIGS. 22 and 23 . Hot exhaust gas enters housing 610 through exhaust gas inlet 612 . It is to be mentioned that, unlike assembly 10 where exhaust gas enters through inlet 36 perpendicular to the direction of flow through its housing, exhaust gas inlet 612 is substantially coaxial with the direction of flow through housing 610 . Thus, the gas inlet 612 and the gas outlet 614 of the housing 610 are disposed along the same general axis (see FIGS. 20 and 21 ).

Exhaust gas entering housing 610 is split into two streams. Internal flow 616 enters chamber 618 and then flows into combustion chamber 620 through a plurality of holes 622 , 624 . The hole arrangement of the holes 622, 624 is shown in FIGS. 24 and 25 . The hole arrangement is configured such that exhaust gas flowing through the holes 622 swirls within the combustion chamber 620, thereby facilitating mixing of injected fuel, exhaust gas, and combustion gases. One or more rows of holes 622 may be utilized to create the desired flow/vortex. As shown in FIGS. 24 and 25 , a plurality of apertures 626 may also be defined in the upstream wall 628 of the combustion chamber 620 so that a portion of the exhaust flow may enter the chamber 620 without first proceeding through the chamber 618 .

The ends of the electrodes 48, 50 are placed downstream of the nozzle 54 to ignite the fuel in the presence of exhaust gases. The exhaust gas contains 4%-20% oxygen, which facilitates the combustion of fuel. Exhaust gases passing through holes 624 mix with hot combustion gases that may contain unburned fuel, hydrocarbons, CO, and other combustible gases. In the presence of oxygen in the exhaust gases, these gases are further combusted. The exhaust gas flows through a number of holes 630 , bypassing the fuel fired combustor 606 . This bypass of exhaust gases supplies additional oxygen for the combustion of the combustion gases exiting the internal combustion chamber 620 .

A flame holder 632 is placed downstream of the combustion zone to prevent flames from reaching the diesel oxidation catalyst 608 (or filter substrate 60 in configurations without a diesel oxidation catalyst, as shown in FIG. 21 ). Gas distributor 634 may be positioned downstream of the combustion zone to facilitate mixing of hot combustion gases and exhaust bypassing fuel fired combustor 606, thereby enhancing the temperature across the inlet of diesel oxidation catalyst 608 and/or filter substrate 60 distributed. Distributor 634 may be positioned around a portion of the wall of combustion chamber 620, as shown in FIG. 22 . An exemplary design of a gas distributor 634 that may be positioned in this manner is shown in FIG. 26 . Alternatively, as shown in FIG. 27 , gas distributor 634 may be positioned downstream of the outlet of combustion chamber 620 . An exemplary design of a gas distributor 634 that may be positioned in this manner is shown in FIG. 28 .

Referring now to FIG. 27 , another exemplary design of a fuel fired combustor is shown in greater detail. In this embodiment, some of the exhaust gas flows through holes 622, which have a hole arrangement similar to that shown in Figure 24, thereby creating a gas vortex within the combustion chamber. A hot flame containing unburned fuel, hydrocarbons, CO, and other combustible gases burns further downstream in the assembly of FIG. 27 relative to that of FIG. 22 .

As shown in FIG. 27 , an additional flame holder 636 may be positioned between the flame holder 632 and the fuel fired burner 606 . The flame support 636 can be designed in a concave configuration as shown in solid lines or in a convex configuration as shown in dashed lines.

Other variations of the exemplary designs of the emission reduction assemblies described herein are also contemplated. For example, as described above, air pump 90 may be implemented as any type of air pump including a relatively high flow/high efficiency air pump. A variable airflow pump that increases output under high engine load conditions is also available. Alternatively, a variable airflow pump operating only under high engine load conditions may also be used. The pump 90 can be implemented with a centrifugal compressor or a Roots blower.

The size of the combustion chamber 34, 620 may also be varied to meet the needs of a given system design. For example, a relatively large (16" diameter) combustor 34, 620 can be used to slow the exhaust gas velocity thereby enhancing the combustion efficiency of a fuel-fired burner. Relatively gentle/efficient airflow configurations can also be used - such as FIGS. 20 and 21 The "axial" configuration shown is used to enhance the flow characteristics of a given design.

The manner in which fuel is injected into the fuel-fired combustors 20, 22, 606 can also be altered if desired. For example, a staged fuel injection approach may be used wherein a first amount of fuel is injected into the combustor to form an initial flame. The injected second fuel quantity is then ignited using the initial flame.

Modified fuel flow patterns can also be used to increase the surface area over which fuel is sprayed. For example, a dithered fuel average may be used, where the injected fuel quantity is dithered around a desired average fuel quantity. For example, the injected fuel rate may be dithered between 25% and 75% to produce an average fuel rate of 50%.

Operation of engine 80 and its associated components may also be controlled to facilitate operation of the emission reduction assemblies described herein. For example, the position of the EGR valve of engine 80 may coincide with regeneration of the particulate filter in the event of operation of an emission reduction assembly that does not utilize supplemental air, such as the assemblies of FIGS. 20 and 21 . For example, the engine's EGR valve may be closed briefly in order to increase the temperature and oxygen content of the exhaust gas. As expected, filter regeneration may take approximately ten minutes. During this short period of time, the EGR valve may be closed. In this case, regeneration of the filter may coincide with engine idle conditions.

In another embodiment, the engine 80 may be controlled such that the EGR level is actually increased during filter regeneration. In this case, a fuel such as hydrogen or a fuel additive may be used to stabilize the flame of the fuel-fired burner. Hydrogen can be supplied from gas storage tanks or from an on-board fuel reformer.

Along similar lines, operation of engine 80 and associated components may be monitored to facilitate operation of the emission reduction assemblies described herein. For example, in the case of operation of an emission reduction assembly that does not utilize supplemental air (i.e., an airless combustor such as the assembly of FIGS. Occurs under certain engine operating conditions. For example, in the case of emission reduction assemblies that do not utilize make-up air, such as the assemblies of FIGS. 20 and 21 , it may be desirable to perform filter regeneration in the presence of exhaust gases containing relatively high oxygen concentrations. Typically, this is the case when the engine 80 is under lower load conditions, such as when the engine 80 is operating at or near idle conditions (eg, 600-1000 RPM, depending on the engine).

As described in more detail below, there are a number of ways to determine when the required, predetermined engine conditions exist for filter regeneration of emission reduction components that do not utilize supplemental air. For example, a predetermined engine speed range may be utilized, in which case regeneration of the filter occurs only when the engine is operating within the predetermined engine speed range. In this case, controller 76 may monitor the output of engine speed sensor 890 (eg, FIG. 8 ) or similar device to determine engine speed. It should be appreciated that the controller may communicate directly with the engine speed sensor 890 or may obtain the output of the sensor 890 from the engine control unit 78 via the CAN interface 314 .

Additionally, a predetermined range of engine loads may be utilized to determine when predetermined engine conditions exist that are required for filter regeneration of the emission reduction assembly not utilizing supplemental air. In this case, regeneration of the filter is only performed when the engine is operating within a predetermined engine load range. To do this, the controller 76 may first sense or otherwise determine certain engine parameters (eg, RPM, turbo boost, etc.) and then query or otherwise obtain a preprogrammed engine load map to determine the load on the engine. It should be understood that the controller 76 may be preprogrammed with such an engine load map, or the engine load may be obtained from an engine load map programmed in the engine control unit 78 via the CAN interface 314 .

In addition, the exhaust mass flow of the engine may be used to determine when there are required, predetermined engine conditions for filter regeneration of the emission reduction assembly not utilizing supplemental air. For example, a predetermined exhaust mass flow range may be utilized, in which case regeneration of the filter occurs only when the engine is operating within the predetermined exhaust mass flow range. In this case, the controller 76 may monitor the output of a mass flow sensor 892 (eg, FIG. 8 ), such as a hot wire mass flow sensor, to determine the discharge mass flow. It should be appreciated that controller 76 may communicate directly with exhaust mass flow sensor 892 or may obtain the output of sensor 892 from engine control unit 78 via CAN interface 314 . Alternatively, exhaust mass flow may be calculated by controller 76 in a conventional manner using such parameters as engine RPM, turbo boost pressure, and inlet manifold temperature (along with other known parameters such as engine displacement, etc.). It should be understood that the controller 76 may calculate mass flow itself, or it may obtain the calculated mass flow from the engine control unit 78 via the CAN interface 314 .

Referring now to FIG. 33 , a control routine 850 for controlling regeneration of an emission reduction assembly not utilizing supplemental air (ie, no air emission reduction assembly) is shown. Routine 850 begins with step 852 where the routine determines whether a request to start an airless fuel fired burner 20 , 22 has been executed (ie, a burner start request). It should be appreciated that the burner activation request may take many different forms, including, for example, by a software control program generating the activation in response to a sensed, timed, or otherwise determined indication that one of the particulate filters 24, 26 requires regeneration. ask. For example, a sensor-based, map-based, or timing-based approach may be utilized to generate the activation request. Thus, in step 852 , if control routine 850 detects a burner start request, a control signal is generated and routine 850 proceeds to step 854 . If the control routine 850 does not detect a burner start request, the routine 850 loops back to step 852 to continue monitoring for such requests.

In step 854, the controller 76 determines whether the engine 80 is operating in a predetermined engine condition. For example, if a predetermined engine speed range is utilized wherein regeneration of the filter occurs only when the engine is operating within the predetermined engine speed range, controller 76 monitors the output of engine speed sensor 890 or otherwise determines the engine speed. Thereafter, controller 76 determines whether the engine speed is within a predetermined speed range. Alternatively, controller 76 senses or otherwise determines certain engine parameters (e.g. RPM, turbo, etc.), then query or otherwise obtain a preprogrammed engine load map to determine the load on the engine. Thereafter, the controller 76 determines whether the engine load is within a predetermined engine load range. Additionally, if a predetermined exhaust mass flow range is utilized, in which case filter regeneration occurs only when the engine is operating within the predetermined exhaust mass flow range, the controller 76 senses, calculates, or otherwise determines the engine exhaust mass flow rate. Mass Flow. Thereafter, the controller 76 determines whether the discharge mass flow is within a predetermined discharge mass flow range. Thus, in step 854 , if controller 76 determines that engine 80 is operating within predetermined engine conditions, control routine 850 proceeds to step 856 . However, if the controller 76 determines that the engine 80 is not operating within the predetermined engine condition, the control routine 850 loops back to step 854 to continue monitoring the engine to determine when it is operating within that condition.

In step 856, the controller 76 initiates regeneration of the filter. Specifically, the electronic controller 76 operates the fuel fired burners 20, 22 to regenerate the particulate filters 24, 26 in any of a number of ways described herein. However, it should be understood that the fuel-fired burners 20 , 22 are operated without combustion air assistance (ie, without utilizing a supplemental air supply, such as from the air pump 90 ). Thus, the oxygen present in the engine exhaust maintains the combustion of the fuel delivered to the fuel fired combustors 20 , 22 . The heat generated by the combustion of the fuel regenerates the particulate filters 24 , 26 . Once filter regeneration is complete, control routine 850 ends.

It should be understood that the filter can also be regenerated by auxiliary make-up air usage control routine 850 if desired. It should also be understood that the control program 850 may be modified in such a way that regeneration of the filter occurs even in the absence of a start request. For example, the controller 76 may be configured to regenerate one or both of the particulate filters 24 , 26 when the engine 80 is operating under predetermined operating conditions, regardless of whether the filters 24 , 26 are loaded to predetermined limits. In this way, the controller 76 may take advantage of the oxygen enrichment conditions at any time present in the exhaust gas.

Referring now to FIG. 35 , another exemplary embodiment of an emission reduction assembly 800 is shown. Assembly 800 includes a nozzle 802 extending into the exhaust conduit for injecting fuel into the exhaust flow. The electrodes 48, 50 are positioned in a generally vertical arrangement (viewed from the direction of the drawing).

The flame holder 636 may be positioned relative to the electrodes 48, 50 in a variety of positions. For example, as shown in FIG. 35 , the flame holder 636 may be positioned downstream of the nozzle 802 but upstream of the electrodes 48 , 50 . Alternatively, flame holder 636 may be positioned downstream of nozzle 802 and electrodes 48 , 50 . Additionally, the flame holder 632 can be designed in a concave configuration (as shown in FIG. 35 ) or a convex configuration (not shown).

Flow divider 644 may be positioned upstream of diesel oxidation catalyst 608 and/or filter substrate 60 to mix hot combustion gases and remaining exhaust gas from the combustion zone near nozzle 802, thereby enhancing flow across diesel oxidation catalyst 608 and/or filter substrate 60. Temperature distribution of the inlet of the substrate 60 . Stream distributor 644 may be implemented as any type of stream distributor. In an exemplary embodiment, the stream distributor 644 may be implemented with any of the stream distributors 634 described above.

Referring now to FIG. 36 , another exemplary embodiment of a fuel fired combustor 20 , 22 is shown. The embodiment shown in Figure 36 is similar to the previous embodiments and like reference numerals are used to designate like parts. Modifications have been made to the fuel fired combustors 20 , 22 to reduce exhaust flow through the combustion chamber 34 . It has been found that such modifications (perhaps significantly) reduce escape of hydrocarbons and carbon monoxide, while reducing other emissions as well.

Essentially, the flow of exhaust gas entering through the exhaust gas inlet 36 is split into two flows, one of which proceeds through the combustion chamber 34 (ie, the combustion flow) and the other bypasses the combustion chamber 34 (ie, the bypass flow). Thus, the flow of exhaust gas through the combustion chamber 34 of the fuel-fired burner 20, 22 of FIG. 36 is reduced relative to, for example, the burner of FIG. 5 . As such, the percentage of exhaust gas flow that bypasses the combustion chamber 34 (ie, proceeds through the opening 42 of the shroud 44 ) is increased relative to the design of FIG. 5 .

As will be described in more detail below, the design of the fuel combustor 34 may be varied to control the flow of exhaust gas therethrough (ie, to control the velocity and direction of the flow of exhaust gas through the combustor). In addition, components such as diverter plates can also be used to control the exhaust gas flow in this way.

An exemplary embodiment of controlling the flow of exhaust gas through the fuel fired burners 20, 22 in this manner is shown in FIG. 36 . In this case, the combustion chamber 34 includes a generally circular outer wall 902 having two half wall portions 904 , 906 . The first half wall portion 904 faces away from the exhaust gas inlet 36 , while the second half wall portion 906 faces the exhaust gas inlet 36 . As shown in FIG. 36 , a plurality of gas inlet openings 40 are defined in the first wall half 904 . The collective surface area of the gas inlet openings 40 of the first half-wall portion 904 defines a first void area, while the collective surface area of the gas inlet openings of the second half-wall portion 906 defines a second void area. The second void area of the second half-wall portion is smaller than the first void area of the first half-wall portion. Thus, a reduced portion of the exhaust gas entering the fuel fired burner 20 , 22 through the exhaust gas inlet 36 flows into the combustion chamber 34 relative to the fuel fired burner design of FIG. 5 , for example. Thus, relative to the design of FIG. 5, the amount of combustion flow (ie, the flow of exhaust gas into the combustion chamber 34) is reduced. It should be appreciated that such an arrangement not only reduces the amount of exhaust gas entering the combustion chamber 34, but also reduces the velocity of the exhaust gas entering the combustion chamber 34 (eg, relative to the design of FIG. 5). In addition, such an arrangement reduces the flow of exhaust gas entering the fuel-fired combustors 20, 22 through the exhaust gas inlet 36 directly into the combustion chamber 34 (ie, through the half-wall portion 906) and thereby impinging on the flame generated therein.

Referring now to FIG. 37 , another embodiment of the fuel fired burner 20 , 22 is shown in which the second half wall portion 906 of the combustion chamber 34 is substantially free of gas inlet openings 40 . For example, the collective surface area of the gas inlet openings of the second half-wall portion 906 defines a void area of zero. In this way, exhaust gas entering the fuel fired burners 20, 22 through the exhaust gas inlet 36 does not flow directly into the combustion chamber 34 and thus does not impinge on the flame generated in the combustion chamber. Instead, the combustion flow of exhaust gas enters the combustion chamber 34 through the gas inlet opening 40 formed in the first half wall portion 904 of the combustion chamber 34 (ie, the surface not facing the exhaust gas inlet 36 ). The balance of the exhaust flow entering the exhaust inlet 36 bypasses the combustion chamber 34 .

It should be appreciated that the size and location of the gas inlet openings 40 on either half-wall portions 904 , 906 may be configured to produce any desired flow characteristics (eg, velocity and direction) within the combustion chamber 34 .

Although the proportion of divided flows (ie, combustion flow and bypass flow) is a function of gas inlet opening 40 formed in outer wall 902 of combustion chamber 34 as described above, exhaust gas flow entering exhaust gas inlet 36 may be divided in other ways. For example, a plate or "tab" may be secured to the combustion chamber 34 to block any number of gas inlet openings 40 that may already exist in the combustion chamber 34 . An example of such a plate 912 is shown in FIG. 44 . Plate 912 may be positioned around outer wall 902 of combustion chamber 34 of a combustor design such as that shown in FIG. 5 . A seam 918 formed when the two ends 914 of the plate 912 are fastened together faces the exhaust gas inlet 36 . As shown in Figure 45, when the plate 912 is installed in this manner, the exhaust gas flow entering the exhaust gas inlet 36 impinges on the area of the plate 912 without holes (shown generally as shaded area 916), thereby preventing the exhaust gas flow from impinging directly on the combustion chamber. on the flame in chamber 34.

By controlling the flow of exhaust gases through the combustion chamber 34, the stability of the flame produced by the fuel fired burners 20, 22 may be enhanced. In fact, it has been found that it is easier to maintain a stable flame when the velocity of the flame is greater than the velocity of the exhaust gases moving through the combustion chamber 34 . Conversely, when the velocity of the exhaust gases moving through the combustion chamber 34 is greater than the flame velocity, flame instability can result.

As mentioned above, the size, number and location of the gas inlet openings 40 can be predetermined to produce the desired flow through the combustion chamber. In an exemplary embodiment, the fuel-fired combustors 20, 22 are configured such that approximately 70% of the exhaust gas entering through the inlet 36 proceeds through the combustion chamber 34 (the remainder of the exhaust gas bypasses the combustion chamber 34). In another exemplary embodiment, the fuel-fired combustors 20, 22 are configured such that approximately 50%-70% of the exhaust gas entering through the inlet 36 proceeds through the combustion chamber 34 (the remainder of the exhaust gas bypasses the combustion chamber 34). In yet another exemplary embodiment, the fuel-fired combustors 20, 22 are configured such that less than 50% of the exhaust gas entering through the inlet 36 proceeds through the combustion chamber 34 (the remainder of the exhaust gas bypasses the combustion chamber 34). Flow arrangements other than these exemplary flow arrangements are contemplated.

As mentioned above, instead of, or in addition to, the gas inlet opening 40 on the outer wall 902 of the fuel chamber 34, the exhaust gas flow entering the gas inlet 36 can be split into the desired combustion flow and bypass flow in various ways. For example, diverter plates may be used to direct a desired amount of exhaust gas flow through the fuel chamber 34 while directing the remainder of the flow around the fuel chamber. Examples of such plates 910 are shown in Figures 38-43, although other configurations are also contemplated. It should be appreciated that the plate 910 may be configured to direct a desired flow portion through the combustion chamber 34 while preventing back pressure buildup in the exhaust system.

The size, shape and/or location of the opening 42 defined in the bypass cover 44 may also be varied to produce desired flow characteristics. For example, the size, shape, and/or location of openings 42 may be configured to accommodate “hot spots” or “cold spots” on the upstream face of filter substrate 60 . Indeed, thermal analysis can be performed on the filter substrate 60 to determine where such hot or cold spots exist. The size, shape and/or location of the opening 42 defined in the bypass cover 44 may then be altered based on such analysis.

For example, the size of the opening 42 upstream of the cold spot (relative to the exhaust gas flow) may be reduced. This increases the temperature at the cold spot during filter regeneration by reducing the amount of exhaust gas flowing through the cold spot.

Conversely, the size of the opening 42 upstream (relative to the exhaust gas flow) of the hot spot may be increased. This reduces the temperature at the hot spot during filter regeneration by increasing the amount of exhaust gas flowing through the hot spot.

Thus, it is conceivable to construct the bypass cover 44 including a plurality of openings 42 of different sizes to accommodate varying surface temperatures on the upstream surface of the filter substrate 60 .

While specific exemplary embodiments have been shown by way of example in the drawings and detailed description herein, the foregoing disclosure is susceptible to various modifications and changes. It should be understood, however, that there is no intention to limit the above disclosure to the particular forms disclosed, but on the contrary, it covers all modifications, equivalents and changes falling within the principle and scope of the invention.

Several advantages of the invention derive from the various features of the devices, systems and methods described herein. It is to be noted that alternative embodiments of the devices, systems and methods of the present invention may not include all of the features described and still have the advantages of at least some of these features. Those of ordinary skill in the art can easily come up with their own conceived devices, systems and methods that incorporate one or more features of the present invention and fall within the principles and scope of the present invention.

For example, it should be understood that the order of many of the steps of the control routines described herein may be altered. Furthermore, many steps of the control program can be performed in parallel with each other.

Claims (19)

1. operate the method that emission abatement assembly is removed the jet-black in the waste gas of explosive motor for one kind, said method comprising the steps of:

Determine whether engine is operated under predetermined operating conditions, and

If engine is operated under this predetermined operating conditions, then operate fuel-fired burners and come regenerate particulate filters.

2. the method for claim 1, wherein:

Described determining step comprises the engine speed of determining engine whether in predetermined scope, and

Described operating procedure comprises: if the engine speed of engine is then operated fuel-fired burners and come regenerate particulate filters in this predetermined scope.

3. method as claimed in claim 2 wherein, determines whether the engine speed of engine is in the output that the interior step of predetermined scope comprises the monitoring engine velocity sensor.

4. the method for claim 1, wherein:

Described determining step comprises the engine load of determining engine whether in predetermined scope, and

Described operating procedure comprises: if the engine load of engine is then operated fuel-fired burners and come regenerate particulate filters in this predetermined scope.

5. method as claimed in claim 4, wherein, the step whether engine load of determining engine is in the predetermined scope comprises the inquiry engine load map.

6. the method for claim 1, wherein:

Described determining step comprises the discharge mass flow of determining engine whether in predetermined scope, and

Described operating procedure comprises: if the discharge mass flow of engine is in this predetermined scope, then operates fuel-fired burners and come regenerate particulate filters.

7. method as claimed in claim 6 wherein, determines whether the discharge mass flow of engine is in the output that the interior step of predetermined scope comprises the quality monitoring flow sensor.

8. method as claimed in claim 6, wherein, whether the discharge mass flow of determining engine is in step in the predetermined scope comprises from the engine operation parameters of institute's sensing and estimates to discharge mass flow.

9. the method for claim 1, wherein: described operating procedure is included in to replenish under the auxiliary situation of air supply operates fuel-fired burners.

10. the method for claim 1, wherein described emission abatement assembly comprises the no air emission abatement assembly with no air burner operation.

11. an emission abatement assembly that is used for removing from the waste gas of explosive motor jet-black, this assembly comprises:

Particulate filter,

Be positioned at the fuel-fired burners of this particulate filter upstream, and

Be configured to control the controller of this fuel-fired burners, this controller comprises (i) processor and the storage device that (ii) electrically is coupled to this processor, the a plurality of instructions of storage in this storage device, when carrying out by described processor, these instructions make described processor:

Determine whether engine is operated under predetermined operating conditions, and

If engine is operated under this predetermined operating conditions, then operate fuel-fired burners and come regenerate particulate filters.

12. emission abatement assembly as claimed in claim 11, wherein, when carrying out by described processor, described a plurality of instructions further make described processor:

The engine speed of determining engine whether in predetermined scope, and

If the engine speed of engine is then operated fuel-fired burners and is come regenerate particulate filters in this predetermined scope.

13. emission abatement assembly as claimed in claim 12, it further comprises engine speed sensor, wherein, when carrying out by described processor, described a plurality of instructions further make described processor monitoring engine velocity sensor output and determine whether the engine speed of engine is in the predetermined scope.

14. emission abatement assembly as claimed in claim 11, wherein, when carrying out by described processor, described a plurality of instructions further make described processor:

The engine load of determining engine whether in predetermined scope, and

If the engine load of engine is then operated fuel-fired burners and is come regenerate particulate filters in this predetermined scope.

15. emission abatement assembly as claimed in claim 11, wherein, when carrying out by described processor, described a plurality of instructions further make described processor inquiry engine load map and determine whether the engine load of engine is in the predetermined scope.

16. emission abatement assembly as claimed in claim 11, wherein, when carrying out by described processor, described a plurality of instructions further make described processor:

The discharge mass flow of determining engine whether in predetermined scope, and

If the discharge mass flow of engine is then operated fuel-fired burners and is come regenerate particulate filters in this predetermined scope.

17. emission abatement assembly as claimed in claim 16, it further comprises mass flow sensor, wherein, when carrying out by described processor, described a plurality of instructions further make described processor monitor the output of described mass flow sensor and determine whether the discharge mass flow of engine is in the predetermined scope.

18. emission abatement assembly as claimed in claim 16, wherein, when carrying out by described processor, described a plurality of instructions further make described processor estimate to discharge mass flow from the engine operation parameters of institute's sensing.

19. emission abatement assembly as claimed in claim 11, wherein, described emission abatement assembly comprises the no air emission abatement assembly with no air burner operation.

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