DE112007000248T5 - Selective homogeneous compression ignition system - Google Patents

Abstract

A method of operating an internal combustion engine 12, comprising:
selectively operating the engine in the first mode of operation, wherein fuel is injected into compressed fluid to produce a substantially homogeneous mixture of fuel and compressed fluid, and wherein the fuel is ignited by the heat of the compressed fluid;
selectively operating the engine in a second mode of operation, wherein fuel is injected into a gas to produce a substantially homogeneous mixture of gas and fuel, wherein the substantially homogeneous mixture is compressed and the fuel is ignited by the heat of the compressed gas ; and
Determining whether to operate the engine in the first or second operating condition according to engine conditions.

Description

Technical area

The The present disclosure relates generally to internal combustion engines and in particular, the operation of a diesel engine in an operating condition with homogeneous compression-ignition charge (HCCI = homogeneous charge compression ignition).

background

One Diesel engine may typically have a combustion chamber, the is constructed of a piston which is displaceable in a cylinder is mounted. The conventional combustion process in the diesel engine can be due to the direct injection of fuel into the cylinder be initiated after an upward movement of the piston a volume of highly compressed air within the upper part of the cylinder has generated. The fuel can be there almost immediately be ignited that he is in the heavily compressed air is injected, and thus it can be a diffusion flame or Create flame front, which is injected along the clouds of the Fuel extends. The generation of the diffusion flame or Flame front can be the presence of impurities in the Exhaust flow of the diesel engine result. These impurities For example, particulate matter, nitrogen oxides ("NOx") and sulfur compounds.

Due to increased consideration for the environment, engine emission standards have become increasingly stringent. The amount of contaminants in the exhaust stream discharged from the diesel engine may be regulated depending on the type, size, and / or class of engine. One method established by engine manufacturers to comply with the regulations of exhaust flow impurities has been to employ a selective catalytic reduction catalyst ("SCR catalyst") to purify NOx from the engine exhaust stream. The application of the SCR catalyst is described in U.S. Patent No. 6,823,660 revealed by Minami. Minami also discloses that while the SCR catalyst has a high purification rate (NOx reduction) at higher exhaust gas flow temperatures, the ability of the SCR catalyst to clean strongly decreases at idle or under low engine load conditions where the temperature of the exhaust stream falls , One reason for this reduction is that the rate of NOx conversion is strongly influenced by the temperature of the exhaust stream. Minami suggests raising the temperature of the exhaust stream before passing through the SCR catalyst to provide nearly 100% removal of NOx. However, increasing the temperature of the exhaust stream in the manner suggested by Minami requires a rather complex arrangement of valve devices and conduits, and may further require the application of additional fuel and / or energy.

on the other hand This may be the fact that you allow the exhaust flow to be lower Temperatures remains, the presence of larger ones Contain quantities of impurities in the exhaust stream. There newer engines also have a diesel particulate filter ("DPF") can capture the impurities, the fact that allowing these contaminants to reach the diesel particulate filter, cause a blockage and the performance of the diesel particulate filter reduce. Thus, the diesel particulate filter can be frequent Maintenance and / or regeneration require to be satisfactory to work.

The The system of the present disclosure is directed to one or more overcome several of the limitations outlined above.

Summary of the invention

According to one Aspect, the present disclosure is directed to a method of operation be directed to an internal combustion engine. The method may include selectively operate the engine in a first operating condition, by injecting fuel into compressed fluid can be a substantially heterogeneous mixture of fuel and compressed fluid, and wherein Fuel by the heat of the compressed fluid can be ignited. The method may also include selectively operate the engine in a second operating condition, in which fuel can be injected in gas to a substantially homogeneous mixture of gas and fuel to produce, the essentially homogeneous mixture can be compressed and fuel through the heat of the compressed gas to be ignited can. The method may further include determining if the Engine is to operate in the first or second operating state, and although according to engine conditions.

In another aspect, the present disclosure may be directed to an internal combustion engine. The internal combustion engine may include a combustion chamber having a piston and a cylinder, and a fuel injection control device that selectively operates the engine in the first and second operating states and selects the operating state according to engine conditions. In the first operating state, fuel can are injected into the compressed fluid to produce a substantially heterogeneous mixture of fuel and compressed fluid, and fuel can be ignited by the heat of the compressed fluid. In the second mode of operation, fuel may be injected into gas to produce a substantially homogeneous mixture of gas and fuel, wherein the substantially homogeneous mixture may be compressed and fuel ignited by the heat of the compressed gas.

According to In another aspect, the present disclosure can be applied to a Work machine to be directed with an internal combustion engine. The internal combustion engine may include a combustion chamber having a piston and a cylinder and a fuel injection control device that selectively operate the engine in the first and second operating states can and the operating condition according to the engine conditions can choose. In the first operating state, fuel can be injected into compressed fluid to a substantially heterogeneous mixture of fuel and compressed matter To produce fluid and fuel can through ignited the heat of the compressed fluid become. In the second operating state, fuel can be injected in gas be a substantially homogeneous mixture of gas and fuel to produce, wherein compresses the substantially homogeneous mixture can be and fuel through the heat of the compressed Gas can be ignited.

Brief description of the drawings

1 provides a schematic view of a combustion chamber according to an exemplary disclosed embodiment.

2 sees a closer view of the combustion chamber of the 1 in front.

3 sees another view of the combustion chamber of the 1 in front.

4 provides a flowchart of a method according to an exemplary disclosed embodiment.

Detailed description

Now is referred in detail to the drawings. Wherever possible are the same reference numbers throughout the drawings used to refer to the same or the same parts.

1 illustrates a combustion chamber 10 an internal combustion engine 12 , Although only a single combustion chamber 10 It should be noted that the engine 12 may have multiple combustion chambers. The combustion chamber 10 can through a cylinder sidewall 14 , a cylinder end wall 16 and a reciprocating piston 18 can be formed and can be a combustion chamber longitudinal axis 20 exhibit.

The reciprocating piston 18 can be a sliding part or a piston body 22 which can fit tightly into a bore passing through the cylinder sidewall 14 is defined. The piston body 22 can be a top or a piston bottom 24 and a bottom 28 which is operative with a crankshaft 30 by a connecting rod or connecting rod 32 are connected. The piston 18 can reciprocate in the well by sliding back and forth between two positions while performing combustion cycles. The first position may be referred to as a top dead center ("TTC") position corresponding to the position where the piston body 22 farthest from the crankshaft 30 can be. The second position may be referred to as a bottom dead center position ("BDC") corresponding to the position where the piston body 22 closest to the crankshaft 30 can be. Accordingly, top dead center and bottom dead center may define the upper and lower extensions of the piston travel, respectively. Additionally or alternatively, the movement of the piston 18 according to the angular rotation of the crankshaft 30 described by the movement of the piston 18 is caused. For example, the movement of the piston from bottom dead center to top dead center may cause the crankshaft 30 turns 180 degrees or half a turn. When the piston 18 from bottom dead center to top dead center, it can thus be characterized as having run 180 degrees. The reciprocation of the piston 18 between top dead center and bottom dead center may provide power to the crankshaft in a manner known to those skilled in the art.

An inlet connection 34 , an inlet valve 36 , an outlet port 38 and an exhaust valve 40 can around the cylinder end wall 16 be around, like in 2 shown. The inlet valve 36 can in the inlet connection 34 and may be operable to fluidly connect the air inlet port 34 with the combustion chamber 10 connect to. The outlet valve 40 can fluidly with the combustion chamber 10 be coupled and may be operable to the combustion chamber 10 with the outlet port 38 to pair. The inlet connection 34 , the inlet valve 36 , the outlet port 38 and the exhaust valve 40 can in one Working way known to those skilled in the art. Additionally or alternatively, the inlet port 34 and / or the combustion chamber 10 be configured to swirl in fluid and / or gases in the combustion chamber 10 initiate.

A fuel injector 42 can a nozzle tip 44 have, which directly into the combustion chamber 10 through an opening 46 in the cylinder end wall 16 extends. As in 3 shown, the nozzle can 44 be configured to inject fuel, so that fuel clouds 70 over a piston recess 26 in the top 24 of the piston body 22 can be formed. The fuel injector 42 can be concentric or parallel with the longitudinal axis 20 the combustion chamber 10 or may be at an acute angle with respect to the longitudinal axis 20 the combustion chamber 10 extend. Furthermore, the fuel injection device 42 be of any conventional type. For example, the fuel injector 42 be a mechanically operated type, a hydraulically operated type or a common rail type and may be configured for a single mode or a mixed mode operation. When the inlet port 34 and / or the combustion chamber 10 are configured to induce turbulence, as discussed above, that of the fuel injector 42 fuel injected less likely at the cylinder side wind 14 adhere.

In operation, the fuel injector 42 a combustible fuel to the combustion chamber 10 as a function of a control signal. During normal to high load engine operation, the fuel injector may 42 receive a control signal which causes the fuel injector 42 Fuel in the combustion chamber 10 one or more injections. For example, the fuel injector 42 inject a first amount of fuel (a pilot or pilot injection) when the piston 18 at any position between bottom dead center and about 40 degrees before top dead center. The pilot or pre-injection may coincide with the intake air in the combustion chamber 10 mix, and the mixture can be compressed or compressed when the piston 18 to the top dead center position is running. The mixture of pilot injection and intake air may burn when its combustion temperature is reached, such as when the heat of the compressed intake air is sufficient to ignite the pilot injection. The fuel injector 42 may also include a second amount of fuel (a main injection) into the combustion chamber 10 injecting, simultaneously with, that the combustion temperature of the mixture of pilot injection and intake air in the combustion chamber 10 reached or slightly before that. The main injection may then burn to be introduced into the mixture of pilot injection and intake air, at least in part due to being exposed to the heat associated with the mixture of pilot injection and intake air. This can be considered a first operating condition for the engine 12 be designated. Additionally or alternatively, in the first operating state, the pre-injection can be omitted. In such an embodiment, the intake air may be through the piston 18 be compressed when it goes to the top dead center position. The main injection may be injected into the compressed intake air. When the compressed intake air has reached the combustion temperature, then the main injection can ignite immediately after it enters the combustion chamber 10 is initiated, due to. the heat of the compressed intake air. Additionally or alternatively, the main injection may ignite shortly after entering the combustion chamber 10 was injected.

During idling or low load engine operation, the control signal may be changed to cause the fuel injector 42 Fuel in the combustion chamber 10 only injected when the piston 18 closer to bottom dead center. This can be achieved, for example, by modifying the pilot injection from the first operating state and eliminating the main injection from the first operating state. This can be considered a second operating condition for the engine 12 be designated. The designation as "first" and "second" operating state is for explanatory purposes only and has no further meaning. In addition, the terms "low load,""normalload," and "high load" may be relative, for example, the low load condition may be for an engine that does not have an exhaust gas recirculation ("EGR") arrangement (not shown) at or start at about 25% load (about 600 kPa mean effective pressure (BMEP)), while in an exhaust recirculation EGR engine, an idle or low load condition will be at or around 50% load (about 1200 kPa mean effective pressure (BMEP) )).

Consequently It should be noted that the meaning of lower, more normal and higher Load will vary depending on the engine, and that this designation not limiting for the total revealed Concept should be.

The control signal may be selectively controlled by a control device 48 be generated as in 1 shown. The control device 48 can take many forms, including a computer-based system A microprocessor-based system comprising a microprocessor, a microcontroller, or any other suitable control circuit or system. The control device 48 may also include a memory for storing a control program for operating and controlling the combustion chamber 10 and related items. Furthermore, the control device 48 are associated with a set of sensors (not shown) that measure the revolutions per minute, the engine coolant temperature, the oil temperature, the piston position, the intake manifold pressure, the combustion chamber temperature, and / or the exhaust temperature. From the sensed information and / or values indicative thereof, the controller may 48 determine if the engine 12 operates at idle, low load, normal load, or high load conditions, and may vary the amount of fuel flowing to the combustor 10 is delivered, and / or it may timely control the fuel injection. For example, the control device 48 vary the amount of fuel to the combustion chamber 10 by controlling the duration of an injection event where there is a direct relationship between the time duration during which the fuel injector 42 is open (fuel injected) and the injected fuel quantity. Also, the control device 48 control the number of fuel injection events and the timing of each of these combustion events with respect to the combustion cycle. It is also considered that the control device 48 the amount of fuel and / or fuel injection timing may vary according to instructions from a vehicle operator, vehicle maintenance personnel, and so on. In one embodiment, the control device 48 an electronic engine control module or a fuel injector control module, which may be configured to perform the above-mentioned functions.

It is also considered that the control device 48 can split a single fuel injection event into a series of smaller fuel injection events that occur sequentially over a short period of time, such as over a time period of 3 milliseconds or less. To achieve such an effect, the control device 48 cause the fuel injector 42 switches quickly between open and closed positions, similar in a manner of vibratory motion. During the oscillatory motion, fuel may be injected when the fuel injector 42 moves from the closed position to the open position. The use of a plurality of small closely spaced fuel injection events may reduce the likelihood of having fuel on the walls of the combustor 10 attached, thus allowing a more efficient and complete combustion.

The control device 48 can also be the inlet valve 36 and / or the exhaust valve 40 run / operate. For example, the control device 48 an intake valve actuator (IVA) configured to be the intake valve 36 to operate so that the inlet valve 36 between an open position, in the intake air into the combustion chamber 10 into and out of this, a closed position, in the intake air does not flow into the combustion chamber 10 can enter or flow out of it, and move position in between. During operation of the engine 12 In the first operating state, the inlet valve actuating device, the inlet valve 36 close at the time to which the piston 18 reached the bottom dead center or around it. In the second operating state, the intake valve actuating device may close the intake valve 36 until shortly after the time delay to which the piston 18 begins to go to top dead center during a compression stroke. When the piston 18 the compression stroke begins, thus can intake air in the combustion chamber 10 still out of the combustion chamber 10 through the opened inlet valve 36 Shortly thereafter, the intake valve operating device may be the intake valve 36 shut down. Because a lot of intake air due to the delayed closing of the intake valve 36 may leak, a smaller volume of intake air in the combustion chamber 10 be found in the second operating state compared to the first operating state. If less air in the combustion chamber 10 combustion of the fuel can be more difficult. Thus, in the second operating state may be required that the piston 18 to a point closer to top dead center than would be required in the first operating state to provide sufficient heat and pressure in the combustion chamber 10 to generate the combustion (ignition of the fuel). By using the intake valve actuating device to adjust the amount of intake air in the combustion chamber 10 can the control device 48 as such, control the timing of the combustion with respect to the combustion cycle.

A system 64 selective catalytic reduction ("SCR system") may be in fluid communication with the outlet port 38 be. The SCR system 64 For example, a reductant may be added to the exhaust stream of the engine using an injector 67 Inject, wherein the reducing agent, for example, gaseous ammonia, Ammonia in aqueous solution, aqueous urea or ammonia from an ammonia generator (not shown). In the exhaust gas stream, the reducing agent may carry out a hydrolysis process and may be decomposed into two byproducts, for example comprising gaseous ammonia and carbon dioxide. The exhaust gas flow can be via an SCR catalytic converter 66 which may comprise aluminum, titanium or any other suitable metal or alloy as a carrier, and platinum, vanadium oxide, iron oxide, molybdenum oxide or the like as an active member. When the exhaust flow through the SCR catalyst 66 The by-products can react with nitrogen oxides ("NOx") in the exhaust stream and reduce the NOx to molecular nitrogen, which can reduce or limit NOx emissions in the exhaust gas 64 However, the SCR system can reduce NOx emissions in high temperature exhaust gas streams with great efficiency 64 reduce NOx emissions in lower temperature exhaust gas streams with less efficiency. For example, the SCR catalyst 66 work efficiently when supplied with an exhaust stream having a temperature of about 200 ° C or greater. However, an operation of the engine 12 at idle or at low load, produce a flow of exhaust gas at a temperature somewhere between about 90 ° and 200 ° C which, when entering the SCR catalyst 66 can not be warm enough to fully initiate the aforementioned reactions.

A diesel particulate filter 68 ("DPF") may be in fluid communication with the SCR system 64 downstream of the SCR catalyst 66 be. The diesel particulate filter 68 may be of any type of filter known in the art, such as a foam cordierite filter, a sintered metal filter, a ceramic filter, or a silicon carbide filter. The diesel particulate filter 68 may further contain catalyst materials comprising, for example, aluminum, platinum, rhodium, barium, cerium and / or alkali metals, alkaline earth metals, rare earth metals or combinations thereof. Furthermore, at least a part of the diesel particulate filter 68 be arranged in a honeycomb or honeycomb configuration, in a grid configuration and / or other suitable configuration that can provide for the filtering of the contaminants when the exhaust gas flow through the diesel particulate filter 68 running.

One method of establishing an aspect of this disclosure is in 4 shown. The procedure may start with the engine 12 begin (step 50 ). The next step may include determining one or more parameters associated with the engine 12 are associated (step 52 ). The engine parameters may include the sensed values, values indicative thereof, and / or values calculated based thereon. If one or more of the engine parameters are outside of a predetermined range of values (step 54 ), then the control device 48 set the fuel injection timing so that the engine 12 can operate in the second operating state (step 56 ). If the one or more engine parameters are in the predetermined range, then the engine may 12 set the fuel injection timing so that the engine 12 can work in the first operating state (step 58 ). Until the engine 12 is switched off (step 60 ), the control device 48 continuously monitor engine parameters and can selectively based on this information the engine 12 into the first and second operating states. Once the engine 12 is turned off, the process or procedure may end (step 62 ).

Industrial applicability

The disclosed internal combustion engine 12 can be used on diesel driven machines. The motor 12 may have particular applicability to adapting to reduce the amount of undesirable emissions in the exhaust of the work machine without significantly increasing the overall fuel consumption and / or energy expenditure when the work machine is operating under idle or low load conditions.

More stringent emissions standards have made attempts to reduce the smoke and NOx by-products of the combustion process to the engines while maintaining or improving fuel efficiency. Under conditions of normal to high engine load, where the engine 12 In what may be termed a first operating condition, a relatively high temperature exhaust stream may be generated which provides the necessary heat for a catalyst 66 for selective catalytic reduction ("SCR catalyst") and / or a diesel particulate filter ("DPF") 68 necessary to work effectively to reduce the amount of smoke and NOx by-products in the exhaust stream.

Under conditions of normal to high engine load, such as when the engine is running 12 running over 25% load (about 600 kPA mean effective pressure (BMEP)) if the engine 12 has no exhaust gas recirculation ("EGR") arrangement, or over 50% load (about 1200 kPa mean effective pressure) if the engine 12 has an exhaust gas recirculation arrangement, the engine 12 to work in the first operating state. Working in the first operating can have a first amount of fuel (a pilot or pre-injection) in a combustion chamber 10 using a fuel injection device 42 to inject while a piston 18 may be located at or near the bottom dead center position ("BDC"). The pilot injection can mix with the intake air already in the combustion chamber 10 is when the piston 18 performs a compression stroke, moving from bottom dead center to top dead center ("TDC"). The mixture of pre-injection and injection air may burn if sufficient temperature and pressure are achieved. Also, a second amount of fuel (a main injection) into the combustion chamber 10 through the fuel injector 42 at the same time that the combustion temperature of the mixture of pre-injection and injection air is reached, or slightly before. The main injection may ignite that it is injected into the mixture of pilot injection and intake air, or immediately thereafter. The heat for ignition of the main injection may be provided by the heat generated by the compression and / or combustion of the mixture of pilot injection and intake air. In the first operating condition, the temperature of the engine 12 generated exhaust gas stream be at or above 200 ° C, and thus the temperature of the SCR catalyst 66 be at or above 200 ° C, which allows the SCR catalyst 66 efficiently removes NOx from the exhaust stream. Additionally or alternatively, the pilot injection may be omitted in the first operating state, and the main injection may be ignited by the heat provided solely by the compression of the intake air and not by a mixture of intake air and fuel.

Under idle or low engine load conditions, such as when the engine is running 12 operating at or below 25% load (approximately 600 kPa mean effective pressure) when the engine is running 12 has no exhaust gas recirculation ("EGR") arrangement or under 50% load (approximately 1200 kPa mean effective pressure) when the engine is running 12 has an exhaust gas recirculation arrangement, the engine 12 working in a second operating state. Under these conditions, the performance of the SCR catalyst 66 decrease sharply, because the temperature of the engine 12 generated exhaust stream may fall within a range somewhere between about 90 and 200 ° C. The second operating state may be in the engine cycle of the engine 12 be provided to reduce the smoke and NOx by-products while maintaining or improving fuel efficiency. The second operating state may be more accurately referred to as a controlled autoignition (CAI) mode. The combustion process in the second operating state may have substantially simultaneous combustion at a plurality of locations in a combustible mixture and may avoid the main injection associated with the first operating state. This distribution of combustion throughout the mixture can prevent the formation of flame fronts and high temperature local regions associated with the operation of the engine 12 be associated in the first operating state, and thereby the smoke and NOx by-products in the exhaust stream of the engine 12 when working under idle or low load conditions.

The operation of the engine 12 in the second operating state, the steps may include introducing air into the combustion chamber 10 to deliver fuel to the combustion chamber 10 using the fuel injector 42 in order to allow the air and fuel to form a homogeneous mixture, and the homogeneous mixture in the combustion chamber 10 to compress until it ignites itself. Auto-ignition may occur when the heat of the compressed gas is sufficient to ignite the fuel. The mixture of air and fuel can be homogeneous if it has a uniform composition, appearance and properties throughout the mixture. The air and fuel may be heterogeneous with the fuel and air substantially separated and not completely mixed.

In some embodiments, the injection step may be initiated during a range of piston positions ranging from approximately 90 to 40 degrees before top dead center. The precise timing of fuel injection may be controlled electronically by a controller 48 can be controlled, and the optimum timing or timing may depend on both the engine design and its speed and load. It is also considered that other gases go to the combustion chamber 10 can be supplied, such as exhaust gases supplied by the EGR system (not shown), which can increase the temperature of the compressed homogeneous mixture to help cause auto-ignition Considered that the control device 48 also the time of the self-ignition by controlling and / or delaying the opening and closing of an intake valve 36 can affect which selectively the combustion chamber 10 in and out of fluid communication with an air intake manifold (not shown) of the engine 12 brings.

3 which the operation of the engine 12 in the second operating state during conditions in Idle or low load illustrates the compression stroke of the piston 18 at a piston position of about 50 degrees before top dead center. At this point in the combustion cycle, the intake air into the combustion chamber 10 have occurred and may have been compressed and mixed with the fuel coming out of the nozzle 44 is injected. As mentioned above, other gases in the combustion chamber 10 For example, exhaust gases may be present through the exhaust gas recirculation system (not shown). The injected fuel, for example diesel fuel, may be fuel clouds 70 in the combustion chamber 10 form. When the piston 18 leading to top dead center of 50 degrees before top dead center, the fuel and air may have sufficient time to mix homogeneously with one another. The homogeneous mixture can be compressed and eventually ignite itself when the pressure in the combustion chamber 10 exceeds a threshold auto-ignition pressure of the homogeneous mixture. As will become clear in this disclosure, the initiation of the fuel injector 42 that correspond to the control device 48 sends an electrical control signal representing the fuel injector 42 for energizing fuel, and / or actuating one or more valves (not shown) to achieve this. By controlling the fuel injector timing, the control device may 48 selectively the engine 12 into the first and second operating states depending on the engine load conditions.

The ability to switch engine operation from the first operating state during high load conditions to the second operating state during idle or low load conditions may be desirable for many reasons. The combustion process in the second operating state may include reduced smoke, reduced NOx and a decrease in unburned hydrocarbons in the exhaust stream of the engine 12 provide by reducing the formation of harmful high temperature regions in the combustion chamber 10 thus resulting in improved emissions and better fuel economy during idle and low load conditions. Further, due to the reduction in the amount of contaminants in the exhaust stream, frequent blockage or clogging of the SCR catalyst and / or diesel particulate filter by trapped impurities can be avoided, and thus regeneration can be performed less often or not at all while the engine is running 12 works in the second operating state. Since regeneration may typically require additional fuel and / or energy, avoiding regeneration can reduce the fuel and / or energy costs associated with operating the engine 12 are associated.

It will be apparent to those skilled in the art that various modifications and variations on the disclosed system and method can be made without departing from the scope of the disclosure departing. In addition, other embodiments of the disclosed system and method to those skilled in the art Consideration of the description will become apparent. It is intended, that the description and examples are considered as exemplary only being a true scope of the disclosure by the following Claims and their equivalent designs will be shown.

Summary

SYSTEM FOR SELECTIVE HOMOGENEOUS COMPRESSION IGNITION

 One Method for operating an internal combustion engine may comprise, selectively to operate the engine in a first operating state, wherein fuel injected into the compressed fluid can be a substantially heterogeneous mixture of fuel and compressed fluid, and wherein Fuel by the heat of the compressed fluid can be ignited. The method may also include selectively operate the engine in a second operating condition, wherein fuel is injected into the gas to a substantially homogeneous mixture of gas and fuel to produce, the essentially homogeneous mixture is compressed and the fuel ignited by the heat of the compressed gas becomes. The method may further include engine conditions to determine if the engine is in first or second operating condition to operate.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 6823660 [0003]

Claims (10)

Method for operating an internal combustion engine 12 comprising selectively operating the engine in the first mode of operation, wherein fuel is injected into compressed fluid to produce a substantially homogeneous mixture of fuel and compressed fluid, and wherein the fuel is ignited by the heat of the compressed fluid; selectively operating the engine in a second mode of operation, wherein fuel is injected into a gas to produce a substantially homogeneous mixture of gas and fuel, wherein the substantially homogeneous mixture is compressed and the fuel is ignited by the heat of the compressed gas ; and determining whether the engine is to be operated in the first or second operating state according to engine conditions. The method of claim 1, further comprising, the engine ( 12 ) with at least one piston ( 18 ), wherein fuel in the first operating state is injected closer to a top dead center position of the piston than in the second operating state. The method of claim 1, further comprising, the engine ( 12 ) with a catalyst ( 66 ) for selective catalytic reduction, wherein the engine is operated in the second mode of operation when the temperature of the selective catalytic reduction catalyst is below a threshold level. The method of claim 3, wherein the threshold level is about 200 ° C. The method of claim 1, further comprising, the engine ( 12 ) in the second operating state when the engine is idling. Internal combustion engine ( 12 ) comprising: a combustion chamber ( 10 ), which has a piston ( 18 ) and a cylinder ( 14 . 16 ) having; and a fuel injection control device ( 48 ) selectively operating the engine in the first and second operating conditions and selecting the operating condition according to engine conditions; wherein, in the first operating state, the fuel is injected into compressed fluid to produce a substantially heterogeneous mixture of fuel and compressed fluid, and wherein the fuel is ignited by the heat of the compressed fluid; and wherein the fuel in the second operating state is injected into a gas to produce a substantially homogeneous mixture of gas and fuel, wherein the substantially homogeneous mixture is compressed and the fuel is ignited by the heat of the compressed gas. Engine ( 12 ) according to claim 6, wherein fuel in the first operating state is injected closer to a top dead center position of the piston than in the second operating state. Engine ( 12 ) according to claim 6, which further comprises a catalyst ( 66 ) for selective catalytic reduction, wherein the engine is operated in the second mode of operation when the temperature of the selective catalytic reduction catalyst is below a threshold level. Engine ( 12 ) according to claim 8, wherein the threshold level is about 200 ° C. Work machine that has an internal combustion engine ( 12 ) according to any one of claims 6-9.