WO2012117454A1 - Exhaust treatment method for internal combustion engine - Google Patents

Abstract

A method according to the present invention supplies fuel to an exhaust passage (17a) that is farther upstream than an exhaust turbine (25b) of an exhaust turbine supercharger (25), and ignites and burns the fuel so as to heat exhaust guided from an engine (10) to an exhaust purification device (26). The method has a step for extinguishing the ignited flames before the flames reach the exhaust turbine (25b) of the exhaust turbine supercharger (25), by increasing the rotation speed of the exhaust turbine (25b), and controlling the amount of fuel supplied to the exhaust passage (17a) so that the air-fuel ratio of the exhaust flowing into the exhaust turbine (25b) is stoichiometric or slightly lean. According to the present invention, it is possible to suppress a reduction in the thermal durability of the exhaust turbine (25b) caused by the flames generated from burning the fuel supplied to the exhaust passage (17a).

Description

Exhaust gas treatment method for internal combustion engine

The present invention relates to a method for treating exhaust gas led to an exhaust gas purification device in an internal combustion engine in which an exhaust turbine supercharger and an exhaust gas purification device are incorporated.

In recent years, in order to cope with strict exhaust regulations for an internal combustion engine, it is necessary to activate an exhaust purification device at the start of the internal combustion engine and to reliably purify the exhaust even during warm-up. For this reason, Patent Document 1 proposes an internal combustion engine in which an exhaust heating device is incorporated in an exhaust passage upstream of the exhaust purification device. This exhaust heating device supplies high-temperature combustion gas to the exhaust gas purification device prior to warm-up operation of the internal combustion engine, activates the internal combustion engine after activation thereof, and starts the warm-up. . For this reason, the exhaust heating device has a fuel supply valve that supplies fuel to the exhaust passage independently of the combustion chamber of the internal combustion engine, and heats the fuel to ignite the exhaust gas in the exhaust passage. It generally has an ignition device such as a glow plug to be generated.

Special table 2003-522875 gazette

The conventional exhaust heating device disclosed in Patent Document 1 functions only when the internal combustion engine is in a stopped state. Therefore, when the internal combustion engine is in a cold state, it takes a long time from the start of the start operation until the warm-up of the internal combustion engine actually ends, resulting in an increase in wasted fuel consumption. Moreover, it is necessary to incorporate a secondary air supply source such as a blower for sending combustion gas to the exhaust gas purification device when the internal combustion engine is stopped, and a relatively large space for installing this must be secured. Therefore, downsizing of the engine room is hindered. Further, when the exhaust heating device is intended to be operated during the operation of the internal combustion engine, the following problem occurs. That is, in the exhaust heating apparatus described above, it is necessary to efficiently burn the fuel using a limited combustion space in the exhaust passage. However, since the exhaust heating device disclosed in Patent Document 1 is disposed upstream of the exhaust turbine supercharger, the space of the exhaust manifold must be used as a combustion space. As a result, the flame generated by the combustion of the fuel in the exhaust heating device reaches the exhaust turbine blade of the exhaust turbine supercharger, and the turbine blade is further thermally deteriorated to impair its durability.

An object of the present invention is to provide an exhaust treatment method that can suppress a decrease in the thermal durability of a turbine blade due to a flame from an exhaust heating device incorporated in an exhaust passage upstream of an exhaust turbine supercharger. It is to provide.

An exhaust heating method according to the present invention supplies fuel to an exhaust passage upstream of an exhaust turbine of an exhaust turbine supercharger, and ignites and burns the fuel, whereby exhaust that is led from an internal combustion engine to an exhaust purification device. In which the ignited flame is extinguished before it reaches the exhaust turbine of the exhaust turbine supercharger.

In the present invention, the flame generated by the ignition of the fuel supplied from the exhaust heating device is extinguished before reaching the exhaust turbine of the exhaust turbine supercharger.

In the exhaust heating method according to the present invention, the step of extinguishing the flame may include a step of increasing the rotational speed of the exhaust turbine. In this case, the internal combustion engine is EGR: comprising the (E xhaust G as R ecirculation exhaust gas recirculation) device, a step of the step of increasing the rotational speed of the exhaust turbine or narrow the opening of the EGR passage of this EGR device, or closed It may be included. Alternatively, the exhaust turbine of the exhaust turbine supercharger may include a variable vane, and the step of increasing the rotational speed of the exhaust turbine may include the step of reducing the opening of the variable vane. Alternatively, the internal combustion engine may include a throttle valve that controls the opening degree of the intake passage, and the step of increasing the rotational speed of the exhaust turbine may include the step of increasing the opening degree of the throttle valve.

The step of extinguishing the flame includes a step of controlling the amount of fuel supplied to the exhaust passage so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine is stoichiometric or slightly leaner than this. It may be.

According to the exhaust heating method of the present invention, since the ignited flame has a step of extinguishing the flame before reaching the exhaust turbine of the exhaust turbine supercharger, the deterioration of the thermal durability of the exhaust turbine due to the flame is suppressed. can do.

For example, the opening degree of the variable vane of the exhaust turbine of the exhaust turbine supercharger is reduced, the opening degree of the throttle valve is increased, or the opening degree of the EGR passage of the EGR device is reduced or closed. Thus, the flow rate of the exhaust gas flowing into the exhaust turbine can be increased. Further, by controlling the amount of fuel supplied to the exhaust passage so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine is stoichiometric or slightly leaner than the stoichiometric state, it is necessary for combustion of the fuel. The amount of oxygen contained in the exhaust can be minimized. In any case, the generated flame can be quickly extinguished before reaching the exhaust turbine of the exhaust turbine supercharger.

FIG. 1 is a conceptual diagram of an embodiment in which the present invention is applied to a compression ignition internal combustion engine. FIG. 2 is a control block diagram of the main part in the embodiment shown in FIG. FIG. 3 is a map schematically showing the relationship between the engine speed, the fuel injection amount, and the fuel supply area by the fuel supply device. FIG. 4 is a flowchart showing a control procedure of the embodiment shown in FIG.

An embodiment in which the present invention is applied to a compression ignition internal combustion engine will be described in detail with reference to FIGS. However, the present invention is not limited to such an embodiment, and the configuration can be freely changed according to required characteristics. For example, gasoline, alcohol or LNG: The present invention is also effective for an internal combustion engine spark ignition system for igniting this as (L iquefied N atural G as liquefied natural gas) fuel and by the ignition plug.

The main part of the engine system in the present embodiment is schematically shown in FIG. 1 and its control block is shown in FIG. 2. FIG. 1 shows a valve mechanism and a silencer for intake and exhaust of the engine 10 for convenience. Note that this is omitted.

The engine 10 is a compression ignition type internal combustion engine that spontaneously ignites by directly injecting light oil as fuel into the combustion chamber 10a in a compressed state from the fuel injection valve 11.

The amount and injection timing of fuel from the fuel injection valve 11 is supplied to the combustion chamber 10a, due ECU (E lectronic C ontrol U nit ) 13 based on operating conditions of the vehicle including the depression amount of the accelerator pedal 12 by the driver Be controlled. The amount of depression of the accelerator pedal 12 is detected by the accelerator opening sensor 14, and the detection information is output to the ECU 13.

The ECU 13 is based on information from the accelerator opening sensor 14 and various sensors to be described later, an operation state determination unit 13a that determines the operation state of the vehicle, a fuel injection amount setting unit 13b, and a fuel injection valve drive unit 13c. And have. The fuel injection amount setting unit 13b sets the fuel injection amount and the injection timing from the fuel injection valve 11 based on the determination result in the operation state determination unit 13a. The fuel injection valve drive unit 13c controls the operation of the fuel injection valve 11 so that the amount of fuel set by the fuel injection amount setting unit 13b is injected from the fuel injection valve 11 at the set time.

The cylinder head 15 formed with the intake port 15a and the exhaust port 15b respectively facing the combustion chamber 10a has a valve operating mechanism (not shown) including an intake valve 16a for opening and closing the intake port 15a and an exhaust valve 16b for opening and closing the exhaust port 15b. It has been incorporated. The previous fuel injection valve 11 is also incorporated in the cylinder head 15.

A throttle for adjusting the opening of the intake passage 17a via a throttle actuator 18 is connected to the cylinder head 15 so as to communicate with the intake port 15a and defines the intake passage 17a together with the intake port 15a. A valve 19 is incorporated.

The ECU 13 further includes a throttle opening setting unit 13d and a throttle valve driving unit 13e. The throttle opening setting unit 13d sets the opening of the throttle valve 19 based on the determination result in the previous operation state determination unit 13a. The throttle valve drive unit 13e controls the operation of the throttle actuator 18 so that the throttle valve 19 has the opening set by the throttle opening setting unit 13d.

The cylinder block 20 in which the piston 21a reciprocates is attached with a crank angle sensor 22 that detects the rotational phase of the crankshaft 21c to which the piston 21a is connected via the connecting rod 21b, that is, the crank angle, and outputs this to the ECU 13. It has been. Based on the information from the crank angle sensor 22, the driving state determination unit 13a of the ECU 13 grasps the traveling speed of the vehicle in addition to the rotational phase of the crankshaft 21c and the engine speed in real time.

The engine 10 includes an EGR device 24 that guides a part of the exhaust gas flowing in the exhaust passage 23a to the intake passage 17a, an exhaust turbine supercharger 25, an exhaust purification device 26, and an exhaust heating device 27. Yes.

The EGR device 24 mainly intended to reduce nitrogen oxides in the exhaust includes an EGR pipe 28 that defines an EGR passage 28a, and an EGR control that controls the flow rate of exhaust gas that is provided in the EGR pipe 28 and flows through the EGR passage 28a. And a valve 29. The EGR pipe 28 has one end communicating with the exhaust pipe 23 defining the exhaust passage 23a together with the exhaust port 15b, and the other end with the throttle valve 19 and the surge tank 17b disposed on the downstream side of the throttle valve 19 described above. Communicated with the intake passage 17a.

In the present embodiment, when the driving state determination unit 13a of the ECU 13 determines that the vehicle on which the engine 10 is mounted is in a preset EGR driving region, the EGR control valve 29 is set according to the driving state of the vehicle at this time. The opening is set by the EGR amount setting unit 13f of the ECU 13. The EGR valve drive unit 13g of the ECU 13 controls the EGR control valve 29 to the opening set by the EGR amount setting unit 13f, and in other cases, the EGR valve drive unit 13g basically closes the EGR passage 28a in a closed state. The control valve 29 is driven.

An exhaust turbine supercharger (hereinafter simply referred to as a supercharger) 25 performs supercharging to the combustion chamber 10a using the kinetic energy of the exhaust gas flowing through the exhaust passage 23a, and increases intake charging efficiency. belongs to. The supercharger 25 in the present embodiment is a variable nozzle vane turbocharger whose main part is composed of a compressor 25a and an exhaust turbine 25b that rotates integrally with the compressor 25a. The compressor 25 a is incorporated in the intake pipe 17 located on the upstream side of the throttle valve 19. The exhaust turbine 25b is incorporated in the middle of the exhaust pipe 23 connected to the cylinder head 15 so as to communicate with the exhaust port 15b. The exhaust turbine 25b according to the present embodiment is a variable nozzle vane (not shown) whose opening degree is controlled by the ECU 13 via a vane actuator 25c (see FIG. 2) based on the driving state of the vehicle. It has. That is, by operating the vane actuator 25c and changing the opening degree of the variable vane, the utilization efficiency of exhaust kinetic energy can be changed, and as a result, the intake charging efficiency can be changed. As such a supercharger 25, any one that can change the opening degree of the variable vane using the hydraulic pressure or the actuator during the operation of the engine 10 may be used, and a conventionally known one can be adopted. is there.

ECU13 further has the vane opening degree setting part 13h for setting the opening degree of a variable vane according to the driving | running state of a vehicle, and the variable vane drive part 13i for driving a variable vane. The vane opening degree setting unit 13h sets the vane opening degree of the turbine 33b of the supercharger 33 based on the engine rotation speed and the driving state of the vehicle. The variable vane drive unit 13i drives the variable vane via the vane actuator 25c so that the vane opening set by the vane opening setting unit 13h is obtained. In the present embodiment, the opening degree of the variable vane is reduced when the exhaust heating device 27 is operated, and the rotational speed of the exhaust turbine 25b is increased to increase the flow rate of the exhaust gas passing therethrough.

In addition, in order to lower the intake air temperature heated through the compressor 25a due to heat transfer from the exhaust turbine 25b exposed to high-temperature exhaust, in the middle of the intake passage 17a between the compressor 25a and the surge tank 43, An intercooler 25d is incorporated. An air flow meter 30 that detects the flow rate of the intake air flowing through the intake passage 17a and outputs it to the ECU 13 is provided in the intake pipe 17 upstream of the compressor 25a of the supercharger 25. Note that one end of the EGR pipe 28 described above is connected to the exhaust pipe 23 upstream of the exhaust turbine 25b.

The exhaust purification device 26 for detoxifying harmful substances generated by combustion of the air-fuel mixture in the combustion chamber 10a is an exhaust pipe 23 that defines an exhaust passage 23a downstream of the exhaust turbine 25b of the supercharger 25. Built in. Exhaust gas purification device 26 is generally known oxidation catalytic converter and DPF (D iesel P articulate F ilter ) and NO x _(Nitrogen Oxides: nitrogen oxides) may comprise a catalytic converter, such as a catalyst.

The exhaust gas heating device 27 is for heating the exhaust gas led from the engine 10 to the exhaust gas purification device 26 to quickly activate the exhaust gas purification device 26 and maintain the active state. It can also be used for playback processing. The exhaust heating device 27 in the present embodiment includes a fuel supply valve 27a and a glow plug 27b.

A fuel supply valve 27a that supplies fuel for activating or maintaining the activated state of the exhaust purification device 26 is downstream of the connection portion with one end of the EGR pipe 28 and upstream of the exhaust turbine 25b of the supercharger 25. It is attached to the exhaust pipe 23 so as to face the exhaust passage 23a. When the exhaust purification device 26 needs to be warmed up or regenerated, the fuel supply valve 27a basically operates the exhaust heating device 27 in a low-load operation state and supplies fuel toward the exhaust passage 23a. It is like that.

For this reason, in this embodiment, the exhaust temperature sensor 31 is attached to the portion of the exhaust pipe 23 located downstream of the exhaust turbine 25b and upstream of the exhaust purification device 26. The exhaust gas temperature sensor 31 detects the exhaust gas temperature T _n flowing through the exhaust passage 23a immediately before flowing into the exhaust purification device 26, and outputs the detected information to the ECU 13. ECU13 compares the determined temperature T _L which is previously set in order to determine the activity state of the exhaust gas temperature T _n and the exhaust purification device 26 flowing through the exhaust passage 23a, and determines whether the operation of the exhaust heating device 27. Instead of the exhaust gas temperature sensor 31, a catalyst temperature sensor may be incorporated in the exhaust gas purification device 26.

The ECU 13 further includes a fuel supply amount setting unit 13j that sets the amount of fuel supplied from the fuel supply valve 27a, and a fuel supply valve drive unit 13k that controls the operation of the fuel supply valve 27a.

The fuel supply amount setting unit 13j sets the fuel supply amount to the exhaust passage 23a so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine 25b is in the stoichiometric state or slightly leaner than this. For this reason, in the present embodiment, the air-fuel ratio in the exhaust passage 23a located downstream of the connection portion with one end of the EGR pipe 28 and upstream of the attachment position of the fuel supply valve 27a is detected, and this is detected by the ECU 13. An air-fuel ratio sensor 32 for outputting is provided. Based on the information from the air-fuel ratio sensor 32, the fuel supply amount setting unit 13j sets the exhaust passage 23a so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine 25b is in a stoichiometric state or slightly leaner than this. Set the amount of fuel to be supplied.

The fuel supply valve drive unit 13k controls the operation of the fuel supply valve 27a so that the amount of fuel set by the fuel supply amount setting unit 13j is supplied from the fuel supply valve 27a to the exhaust passage 23a.

In this way, when the amount of fuel supplied to the exhaust passage 23a is set, the oxygen concentration contained in the exhaust can be minimized with respect to the amount of fuel supplied from the fuel supply valve 27a to the exhaust passage 23a. As a result, the fuel supplied from the fuel supply valve 27a to the exhaust passage 23a is terminated before the fuel reaches the exhaust turbine 25b of the supercharger 25, thereby preventing a problem that the flame reaches the exhaust turbine 25b. be able to. In the present embodiment, the opening degree of the variable vane of the exhaust turbine 25b of the supercharger 25 is increased during the operation of the exhaust heating device 27, the opening degree of the throttle valve 19 is increased, or the EGR passage 28a of the EGR device 24 is operated. Is closed or closed by the EGR control valve 29. Thereby, it is possible to further ensure the flame extinguishing process described above. When the opening degree of the variable vane of the exhaust turbine 25b is reduced, the opening degree of the throttle valve 19 is increased, the opening degree of the EGR passage 28a is reduced or closed, the exhaust turbine 25b of the supercharger 25 is closed. The flow rate of the inflowing exhaust can be increased. As a result, the rotational speed of the exhaust turret 25b can be increased and extinguished before the flame reaches the exhaust turbine 25b.

It should be noted that an O2 sensor may be used in place of the previous air-fuel ratio sensor 32, or the air-fuel ratio may be calculated based on the fuel injection amount from the fuel injection valve 11 and the intake air amount by the air flow meter 30. It is. When the air flow meter 30 is used, it is attached to the portion of the intake pipe 17 located upstream of the compressor 25a of the supercharger 25, detects the flow rate of the intake air flowing through the intake passage 17a, and outputs this to the ECU 13 To do. Instead of the air flow meter 30, an exhaust flow sensor having the same configuration may be attached to a portion of the exhaust pipe 23 positioned between the exhaust turbine 25 b and the exhaust purification device 26.

The glow plug 27b for igniting the fuel supplied from the fuel supply valve 27a to the exhaust passage 23a is connected to an in-vehicle power source (not shown) via a switch (not shown) controlled on / off by the ECU 13. The operation of the glow plug 27b is switched on / off by the glow plug drive unit 13l of the ECU 13 based on the drive information of the fuel supply valve 27a from the fuel supply valve drive unit 13k.

The operation of the exhaust heating device 27 is controlled based on the driving state of the vehicle and the state of the exhaust purification device 26. Therefore, the ECU 13 determines whether or not the exhaust heating device 27 can be operated based on the engine speed and the amount of fuel injected from the fuel injection valve 11. In the present embodiment, the ECU 13 stores a map representing the relationship between the engine rotational speed, the fuel injection amount from the fuel injection valve 11, and the operable region of the exhaust heating device 27 as shown in FIG. It is then determined whether or not the exhaust heating device 27 can be operated. Further, ECU 13 compares the determination temperature T _L that is set to determine the activated state of the exhaust gas purification device 26 and the exhaust gas temperature T _n flowing through the exhaust passage 23a, determines together whether operation of the exhaust heating device 27 .

The ECU 13 is a well-known one-chip microprocessor, and includes a CPU, a ROM, a RAM, a nonvolatile memory, an input / output interface, and the like interconnected by a data bus (not shown). The ECU 13 performs predetermined arithmetic processing based on detection signals from the sensors 14, 22, 31, 32, the air flow meter 30, and the like described above so that the engine 10 can be smoothly operated. The operations of the fuel injection valve 11, the throttle valve 19, the EGR control valve 29, the fuel supply valve 27a, the glow plug 27b, the vane actuator 25c, and the like are controlled according to a preset program.

The intake air supplied from the intake passage 17a into the combustion chamber 10a forms a mixture with the fuel injected from the fuel injection valve 11 into the combustion chamber 10a. And normally, it spontaneously ignites and burns immediately before the compression top dead center of the piston 21a, and the exhaust generated thereby is exhausted from the exhaust pipe 23 into the atmosphere through the exhaust purification device 26 in a detoxified state. .

The regeneration process of the exhaust purification device 26 includes the cumulative fuel injection amount injected from the fuel injection valve 11, the cumulative operation time of the engine 10, the exhaust pressure upstream of the exhaust purification device 26, and the exhaust pressure downstream. This is based on information such as the differential pressure. In the present embodiment, the ECU 13 supplies fuel into the exhaust passage 23a from the fuel supply valve 27a in addition to the fuel injection amount from the fuel injection valve 11 for regenerating the exhaust purification device 26. That is, the fuel supply operation from the fuel supply valve 27a into the exhaust passage 23a is basically performed when the exhaust purification device 26 is in an inactive state. However, in order to perform the regeneration process of the exhaust purification device 26 quickly, the fuel can be supplied also from the fuel supply valve 27a into the exhaust passage 23a.

As a result, in addition to activating and maintaining the activated state of the exhaust purification device 26, the regeneration process can also be performed quickly. In particular, the exhaust heating device 27 is extremely advantageous for improving a so-called cold emission state immediately after the engine 10 is cold-started.

The operation procedure of the exhaust heating device 27 in this embodiment will be described with reference to the flowchart of FIG. 4. First, the exhaust temperature T _n detected by the exhaust temperature sensor 31 in step S1 is equal to or lower than the catalyst activation temperature _TL. It is determined whether or not. Here, when it is determined that the exhaust temperature T _n is equal to or lower than the catalyst activation temperature _TL , that is, it is necessary to heat the exhaust purification device 26 to activate it or to maintain its activated state, The process proceeds to step S2. In step S2, based on the information from the crank angle sensor 22 and the information from the fuel injection amount setting unit 13b, the current operation state of the engine 10 is in an operation region in which fuel can be supplied from the fuel supply valve 27a. It is determined whether or not. Here, if it is determined that the current driving state of the vehicle is in an operating region in which the exhaust heating device 27 can be operated, that is, it is preferable to supply fuel to the exhaust passage 23a to heat the exhaust, the process of S3 Move to step. In step S3, the glow plug 27b is switched on in the energized state, and fuel is supplied from the fuel supply valve 27a to the exhaust passage 23a. As a result, the combustion gas, which has been ignited by the fuel and heated to a high temperature, is led from the exhaust passage 31a to the exhaust purification device 26 via the exhaust turbine 25b.

* Following the step of S3, the flame extinguishing process is executed in the step of S4. More specifically, the opening degree of the variable vane of the exhaust turbine 25b of the supercharger 25 is reduced, the opening degree of the throttle valve 19 is increased, the opening degree of the EGR passage 28a of the EGR device 24 is reduced, or Close. Alternatively, the amount of fuel supplied from the fuel supply valve 27a to the exhaust passage 23a is set so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine 25b is in the stoichiometric state or slightly leaner than the stoichiometric state. Control is performed by the setting unit 13j. When the opening degree of the variable vane of the exhaust turbine 25b is reduced, the opening degree of the throttle valve 19 is increased, the opening degree of the EGR passage 28a is reduced or closed, the exhaust turbine 25b of the supercharger 25 is closed. The flow rate of the inflowing exhaust can be increased. As a result, the flame can be extinguished. In addition, when the fuel supply amount is set by the fuel supply amount setting unit 13j so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine 25b is almost stoichiometric, the fuel amount supplied to the exhaust passage 23a The oxygen concentration contained in the exhaust gas is minimized. As a result, the fuel supplied from the fuel supply valve 27a to the exhaust passage 23a is terminated before the fuel reaches the exhaust turbine 25b of the supercharger 25, thereby preventing a problem that the flame reaches the exhaust turbine 25b. be able to.

Thereafter, it is determined in step S5 whether or not a flag indicating the operation of the exhaust heating device 27 is set. At first, since the flag is not set, the process proceeds to step S6, the flag is set and the process returns to the first step S1, but since the flag is set after the second time, the steps after S1 are repeated as they are. It is.

If it is determined in the previous step S2 that the current driving state of the vehicle is not a driving state suitable for operating the exhaust heating device 27, the process proceeds to step S7. In step S7, it is determined whether or not a flag is set. If it is determined that the flag is set, that is, the exhaust heating device 27 is operating, the process proceeds to step S8. In step S8, the glow plug 27b is switched off in a non-energized state and the supply of fuel from the fuel supply valve 27a to the exhaust passage 23a is stopped, and the flame extinguishing process performed in step S4 is terminated. Thereby, the operation of the exhaust heating device 27 is finished.

Following the step of S8, the flag is reset at the step of S9, and the control relating to this exhaust heating process is ended.

It should be noted that the present invention should be construed only from the matters described in the claims, and in the above-described embodiment, all the changes and modifications included in the concept of the present invention are other than those described. Is possible. That is, all matters in the above-described embodiment are not intended to limit the present invention, and include any configuration not directly related to the present invention. To get.

DESCRIPTION OF SYMBOLS 10 Engine 10a Combustion chamber 11 Fuel injection valve 12 Accelerator pedal 13 ECU
13a Operation state determination unit 13b Fuel injection amount setting unit 13c Fuel injection valve driving unit 13d Throttle opening setting unit 13e Throttle valve driving unit 13f EGR amount setting unit 13g EGR valve driving unit 13h Vane opening setting unit 13i Variable vane driving unit 13j Fuel supply amount setting unit 13k Fuel supply valve drive unit 13l Glow plug drive unit 14 Accelerator opening sensor 15 Cylinder head 15a Intake port 15b Exhaust port 16a Intake valve 16b Exhaust valve 17 Intake pipe 17a Intake passage 17b Surge tank 18 Throttle actuator 19 Throttle Valve 20 Cylinder block 21a Piston 21b Connecting rod 21c Crankshaft 22 Crank angle sensor 23 Exhaust pipe 23a Exhaust passage 24 EGR device 25 Exhaust turbine supercharger 25a Compressor 5b exhaust turbine 25c vane actuator 25d intercooler 26 exhaust gas purification device 27 an exhaust heating device 27a a fuel supply valve 27b glow plug 28 EGR pipe 28a EGR passage 29 EGR control valve 30 air flow meter 31 exhaust temperature sensor 32 air sensor

Claims (6)

This is a method for heating the exhaust led from the internal combustion engine to the exhaust purification device by supplying fuel to the exhaust passage upstream of the exhaust turbine of the exhaust turbine supercharger and igniting and burning the fuel. And
An exhaust heating method comprising the step of extinguishing a flame before ignited flame reaches the exhaust turbine of the exhaust turbine supercharger. The exhaust heating method according to claim 1, wherein the step of extinguishing the flame includes a step of increasing a rotational speed of the exhaust turbine. The said internal combustion engine is provided with an EGR apparatus, The step which raises the rotational speed of the said exhaust turbine includes the step which restrict | squeezes the opening degree of the EGR path | route of this EGR apparatus, or closes. Exhaust heating method. The exhaust turbine of the exhaust turbine supercharger includes a variable vane, and the step of increasing the rotational speed of the exhaust turbine includes the step of reducing the opening of the variable vane. 3. The exhaust gas heating method according to 3. 3. The step of increasing the rotational speed of the exhaust turbine includes a step of increasing the opening of the throttle valve, wherein the internal combustion engine includes a throttle valve that controls the opening of the intake passage. The exhaust gas heating method according to claim 4. The step of extinguishing the flame controls the amount of fuel supplied to the exhaust passage so that the air-fuel ratio of the exhaust gas flowing into the exhaust turbine is in a stoichiometric state or slightly leaner than the stoichiometric state The exhaust heating method according to claim 1, further comprising a step.

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