JP2008504481A - Fueling a diesel engine by selectively using a fueling map to extend the range of HCCI combustion - Google Patents

Abstract

  The compression ignition engine (60) has a control system (66) that processes data, one or more combustion chambers (62), and an injector (64) that injects fuel into the combustion chambers. In the first embodiment, the control system selects one of three fuel delivery modes (HCCI + RVT, HCCI + VVT, CD + RVT) for processing engine speed and engine load to operate the engine (FIG. 1). This controls the fuel supply. In the second embodiment, one of four modes (HCCI + RVT, HCCI + IVC, HCCI + IVC, + EVC, CD + RVT) is selected (FIG. 5). The present invention extends the scope of utilizing HCCI combustion.

Description

  The present invention generally relates to internal combustion engines. More particularly, the present invention relates to a control scheme that selectively utilizes homogeneous charge compression ignition (HCCI) in a manner that utilizes HCCI attributes in various ways during various modes of operation of an engine having variable valve timing. .

  HCCI is a known process for refueling a diesel engine in a manner that creates a substantially homogeneous air and fuel charge (supply mixture) inside the engine cylinder during the compression upstroke of the engine cycle. After charging the desired amount of fuel into the cylinder to create a substantially homogeneous air / fuel mixture, the charge compression by the piston during the up stroke causes charge self-ignition. A sufficiently large pressure is generated. In other words, the HCCI operating mode of the diesel engine is as follows: 1) During the compression up stroke, a desired amount of fuel is injected into the cylinder at an appropriate time, and the injected fuel is in the initial stages of the intake down stroke and the compression up stroke. The mixing of the supply air flowing into the cylinder during the part with the mixing in such a way as to form a substantially homogeneous mixture in the cylinder, and then 2) near top dead center (TDC) or It can be said that it has a step of further compressing the air-fuel mixture to the extent that it can be called self-ignition. Autoignition can occur as substantially simultaneous instantaneous combustion of vaporized fuel at various locations within the mixture. After self-ignition, no additional fuel is injected.

One of the attributes of HCCI is that a relatively lean or lean mixture can be burned, thereby keeping the combustion temperature relatively low. By avoiding the occurrence of relatively high combustion temperatures, HCCI can lead to a significant reduction in NO _x , an undesirable component of engine exhaust.

  Another attribute of HCCI is that the substantially homogeneous air and fuel charge self-ignition results in more complete combustion, resulting in relatively low soot in the engine waste. It is in.

  Thus, the potential benefits of HCCI for reducing tailpipe emissions are significant, and thus HCCI is the subject of active research and development by scientists and engineers in the engine research and design industry. It is.

A Problem of HCCI, this seems to be to impose constraints on the degree to which it can result in a dramatic reduction in tailpipe emissions of soot and NO _X. At high engine speeds and high engine loads, the combustion rate is difficult to control. Thus, known engine control schemes may utilize HCCI only at relatively low speeds and relatively low engine loads. At high speeds and / or high loads, fuel is injected into conventional diesel (CD) when injected into the charge compressed in the cylinder to a pressure high enough to burn the fuel while injecting the fuel. ) The engine is refueled to burn by the combustion method.

  With the advent of processor-controlled fuel injection systems that can control fuel injection with high precision that can inject fuel at different injection pressures, at different times, and for different periods of time during the engine cycle over the full range of engine operation, diesel engines Can perform both CD combustion and HCCI combustion.

  As will be described below, the present invention utilizes a processing system that controls fuel injection in various ways depending on certain aspects of these fuel injection functions and engine operation. More precisely, how the particular fuel injection system is controlled by the associated processing system in any given engine will depend on the details of the engine, fuel injection system and processing system.

  Because diesel engines that power automobiles operate at different speeds and different loads depending on the different inputs to the automobile and engines that affect engine operation, refueling requirements are variable speed and load. As it changes. The associated processing system processes data representing parameters such as engine speed and engine load to ensure proper control of the fuel injection system for various combinations of engine speed and engine load as desired. Generate control data to set engine refueling.

  US patent application Ser. No. 10 / 809,254, filed Mar. 25, 2004, describes a diesel engine and a plurality of fuel delivery modes for operating certain engines to process certain data. An associated processor-controlled fuel injection system for selecting one is disclosed. If the first fuel supply mode (HCCI mode) is selected as a result of the process, the engine is refueled during one engine cycle and substantially one or more combustion chambers are charged with air and fuel. Give rise to This charge is compressed to burn by self-ignition and no further fuel is introduced after self-ignition. When the second fuel supply mode (HCCI-CD mode) is selected according to the processing result, the engine is refueled during the engine cycle and substantially homogeneous air and fuel are contained in one or more combustion chambers. Generate a charge. This charge is compressed to burn by auto-ignition (HCCI), after which fuel is further introduced into one or more combustion chambers to produce additional combustion (CD). The engine utilizes HCCI combustion at a relatively low load and relatively low speed, and utilizes a condition called HCCI-CD combustion at a relatively high load and relatively high speed.

Engine invention, undesirable components in the engine waste for achieving objectives, especially including one stage of reduction of generation of soot and NO _X, which facilitate the use of HCCI combustion in a diesel engine, to improve the thermal efficiency, the system And a method. The present invention is embodied in a fuel injection control scheme that is a scheme programmed into an associated processing system.

  In accordance with the principles of the present invention, the use of HCCI combustion is performed in a manner different from that described in US patent application Ser. No. 10 / 809,254. The first disclosed embodiment of the present invention has three separate engine operating modes: 1) HCCI + RVT mode, 2) HCCI + VVT mode, 3) CD + RVT mode. Each of these modes will be described in detail below. The HCCI + RVT mode is utilized at a relatively low load and relatively low speed. The HCCI + VVT mode is utilized at a relatively higher load than that of the HCCI + RVT mode and at a relatively higher rate than that of the HCCI + RVT mode. The CD + RVT mode is utilized at a higher load than the HCCI + VVT mode load and at a relatively higher rate than the HCCI + VVT mode speed.

  With the HCCI + VVT mode, the benefits of the HCCI mode can be obtained in the part of the engine operating range between the part of the range where HCCI + RVT is exclusively used and the part of the range where CD + RVT is exclusively used.

  In HCCI + VVT mode, intake valve closure is delayed relative to HCCI + RVT mode intake valve closure.

  The second embodiment of the present invention provides a means that can be considered an improvement of the HCCI + VVT mode. One way to consider the improvement is by defining the HCCI + VVT mode as consisting of two modes rather than a single mode. Such a definition is not necessarily interpreted to mean that the limits or boundaries of the HCCI + VVT mode remain unchanged. In contrast, it is believed that providing two separate modes rather than a single mode can further extend the effective range of HCCI combustion, especially at higher speeds and higher load directions.

  Therefore, another way of defining the second embodiment of the present invention is by four separate modes: 1) HCCI + RVT mode, 2) HCCI + IVC mode, 3) HCCI + IVC + EVC mode, 4) CD + RVT mode. In the HCCI + RVT mode, fuel is supplied to the engine and the valve is operated in the same manner as in the first embodiment for the same mode. In the HCCI + IVC mode, fuel is supplied to the engine, and the valve is operated in accordance with the HCCI + VVT mode of the first embodiment. In this case, the effective compression ratio is decreased by delaying from the intake valve closing in the intake valve closing HCCI + RVT mode. . In the CD + RVT mode, fuel is supplied to the engine and the valve is operated for the same mode as in the first embodiment.

The second embodiment is different from the first embodiment in that it has an HCCI + IVC + EVC mode. Over a range of engine speeds and engine loads where the engine is operating in HCCI + IVC mode, but lower than engine speeds and engine loads where the engine is operating in CD + RVT mode, the variable valve timing system is in the HCCI + IVC mode. It operates to delay the closing time of the exhaust valve compared to the closing time of the exhaust valve. By delaying the timing exhaust valve closing, reducing the proportion of residual hot gases in the cylinders, thereby reducing the cylinder temperature and pressure, thus reducing the certain engine emissions, such as of the NO _X Benefits are gained.

  One general feature of the present invention is a method of operating a compression ignition engine comprising the steps of: a) processing certain data to select one of a plurality of fuel delivery modes for operating the engine. And b) if the first mode is selected, fuel one or more combustion chambers to charge substantially homogeneous air and fuel into each of the combustion chambers during the corresponding engine cycle. And compressing each of the charges to self-ignite, in which case no additional fuel is introduced after the self-ignition during the corresponding engine cycle, and c) if the second mode is selected, During the corresponding engine cycle, the effective compression ratio of each of the combustion chambers is decreased with respect to the effective compression ratio for the first mode, and an increased amount of fuel is supplied to each of the combustion chambers for the fuel supply for the first mode. , Creates a substantially homogeneous air and fuel charge in each of the firing chambers and compresses each of the charges to self-ignite, with no additional fuel being introduced after self-ignition during the corresponding engine cycle To a method comprising the steps of:

  More specific features are described in the dependent claims describing the method.

  Another general feature is a compression ignition engine, a control system that processes data, one or more combustion chambers, and a fuel supply that injects fuel into one or more combustion chambers. And a control system a) selects one of a plurality of fuel delivery modes to process certain data and operate the engine, and b) selects the first mode, One or more combustion chambers are fueled to produce a substantially homogeneous air and fuel charge in each of the combustion chambers during the corresponding engine cycle, and each of the charges is compressed to self-ignite. In this case, no additional fuel is introduced after self-ignition during the corresponding engine cycle, and c) when the second mode is selected, each of the combustion chambers for the effective compression ratio for the first mode. Reduce the effective compression ratio, An increased amount of fuel is supplied to each of the combustion chambers relative to the fuel supply for one mode to produce a substantially homogeneous air and fuel charge in each of the combustion chambers during the corresponding engine cycle, Each relates to an engine that controls the fuel supply system by compressing and self-igniting, in which case no additional fuel is introduced after self-ignition during the corresponding engine cycle.

  More specific features are described in the dependent claims describing the engine.

  In the disclosed embodiment of the present invention, the data processed to select a particular mode consists of engine speed and engine load data. The injection pressure, the injection period, and the injection timing may be different for each mode. Data regarding the various modes is stored in a map in the engine control system.

  The foregoing will be understood in the following description of the presently preferred embodiment of the invention, which describes the best practice of implementing the invention at this point, as well as further features and advantages of the invention. The present application includes drawings that will be outlined later.

  FIG. 1 is a graph showing the engine load on the vertical axis and the engine speed on the horizontal axis. At the origin of the graph, the engine load is zero and the engine speed is zero. Solid lines 50, 52, 54 define three zones labeled HCCI + RVT, HCCI + VVT, and CD + RVT. RVT represents a periodic valve opening / closing timing of the engine intake valve, and VVT represents a variable valve timing of the engine intake valve.

  Zone HCCI + RVT covers an area that includes various combinations of relatively low engine load and relatively low engine speed. Zone HCCI + VVT covers an area that includes various combinations of higher engine loads and higher engine speeds than zone HCCI + RVT. Zone CD + RVT covers an area that includes various combinations of higher engine loads and higher engine speeds than zone HCCI + VVT. When the compression ignition engine is operating at a speed and load belonging to the zone HCCI + RVT, fuel is injected into the engine cylinders in such a way as to cause HCCI combustion. When the engine is operating at a speed and load belonging to the zone HCCI + VVT, fuel is injected into the engine cylinder in a manner that causes HCCI combustion. When the engine is operating at a speed and load belonging to zone CD + RVT, fuel is injected into the engine cylinder in a manner that causes CD combustion.

  FIG. 2 schematically illustrates a portion of an exemplary diesel engine 60 that operates in accordance with the inventive scheme described in FIG. 1 for powering an automobile. The engine 60 has a cylinder 62 in which a piston reciprocates. Each piston is connected to a respective stroke part of the crankshaft by a corresponding connecting rod. When the intake valve of each cylinder is opened, intake air (intake) is sent to each cylinder through an intake system (not particularly shown in the drawing).

  The engine has a fuel supply system with an injector 64 for the cylinder 62. The engine further includes a processor-based engine control unit (ECU) 66 that processes data from various sources to produce various control data for controlling various attributes related to engine operation. Data processed by ECU 66 may come from external sources, such as various sensors 68, and / or originate internally. Examples of the processing data include engine speed, intake manifold pressure, exhaust manifold pressure, fuel injection pressure, fuel supply amount, fuel supply timing (timing), mass flow rate, and accelerator pedal position.

  The ECU 66 controls fuel injection into the cylinder 62 by controlling the operation of the fuel supply system including the operation of the injector 64. The processing system embodied in the ECU 66 processes the data quickly enough to calculate the device operation timing and the device operation period in real time to set both the fuel injection timing and the fuel injection amount into the cylinder. can do. Such a control function is used to embody the system of the present invention.

  The engine 60 further includes a VVT system 70 that is controlled by the ECU 66. The VVT system may be of any of a variety of known types, such as a “camless” type. The VVT system can change when the intake valve of the cylinder operates, and therefore can change the effective compression ratio of the engine cylinder, which will be described in detail below.

  Regardless of how data values relating to engine speed and engine load are generated, this particular embodiment of the present invention uses the instantaneous engine speed and instantaneous engine load to determine the specific fuel delivery mode for the engine, i.e. 1 ) Select HCCI + RVT mode for generating HCCI combustion, 2) HCCI + VVT mode for generating HCCI combustion, 3) CD + RVT mode for generating CD combustion, and then select the fuel supply system according to the mode of the selected fuel supply mode. Operate and fuel the engine. As a modification, the method of selecting a specific mode may use only the engine load.

  FIG. 3 shows a flowchart 71 relating to the method of the present invention executed by the processing system of the ECU 66. Reference numeral 72 represents the start of processing executed by this method. In step 74, engine speed data and engine load data are processed to determine which of the three fuel delivery modes of FIG. 1 should be selected. One approach to selecting a mode is to provide one or more maps to the processing system to define three zones and compare data values for instantaneous engine speed and engine load according to the maps.

  If step 74 selects the HCCI + RVT mode, FIG. 3 shows that fuel is injected into each cylinder to cause HCCI combustion in all cylinders (reference numeral 76) at regular valve timing RVT (reference numeral 77). Show. This operation continues until completion, at which point the flowchart process is repeated.

  When step 74 selects the HCCI + VVT mode, FIG. 3 shows that fuel is injected into each cylinder to cause HCCI combustion in all cylinders (reference numeral 78), where the intake valve opening and closing timing is variable valve It can be changed by the timing system 70 (reference numeral 79). This operation continues until completion, at which point the flowchart process is repeated.

  If step 74 selects the CD + RVT mode, FIG. 3 shows that fuel is injected into each cylinder to cause CD combustion in all cylinders (reference number 80) at regular valve timing RVT (reference number 81). Show.

In the HCCI + RVT mode, fuel is injected to produce HCCI combustion using regular valve timing (RVT). FIG. 4A shows a general example of fuel supply for the HCCI + RVT mode. This example has a zone 82 with a relatively high fuel injection pressure and a relatively short fuel injection period, where the fuel enters the cylinder and mixes well with air before self-ignition and the resulting combustion products. NO _X and soot emissions are possible wherein less.

In the HCCI + VVT mode, fuel is injected to cause HCCI combustion. By changing the effective compression ratio of the engine by using variable valve timing, HCCI can be implemented at a higher load and higher speed than in the HCCI + RVT mode. FIG. 4B shows a general example of fuel supply for the HCCI + VVT mode. This example shows how fuel can be added to the cylinder to better mix with air before self-ignition as required by increased load and / or higher speed compared to HCCI + RVT mode. It has a zone 84 in which the injection pressure is relatively higher than the fuel injection pressure of the zone 82. In the HCCI + VVT mode, the VVT system 70 operates to reduce the effective compression ratio as seen from the RVT compression ratio. As a result, the in-cylinder pressure decreases and the peak combustion temperature decreases. Thus, depending on the specific engine load, the fuel injection period may be somewhat longer than the fuel injection period of zone 82. Accordingly, the HCCI combustion range is expanded to include the two zones of FIG. 1, with low amounts of NO _x and soot emissions in both zones.

In CD + RVT mode, the engine is fueled to cause CD combustion. FIG. 4C shows a general example of fuel supply for the CD + RVT mode. This example shows a zone 86 characterized in that the fuel injection pressure is relatively lower than in either the zone 82 or the zone 84, the fuel injection timing is advanced, and the fuel injection period is long. The CD + RVT mode, the engine 60 can satisfy the high speed and high load requirements, combustion products, including typical NO _X and soot emissions.

  The following relational expression shows how VVT can change the effective compression ratio in a diesel engine. By definition, the following equation 1 holds.

Effective compression ratio = (Effective displacement amount + gap volume) / gap volume Equation 1
In the above equation, the gap volume in the diesel engine is constant. When the intake valve opening / closing timing is changed by VVT, the effective displacement amount of the engine changes as follows.

^{_{V eff-dis = πB 2/}} 4 (l + α-αcosθ-√ (l 2 -α 2 sin 2 θ)) Equation 2
In Equation 2 above, V _eff-dis is the effective displacement of the engine, B is the cylinder bore diameter, l is the connecting rod length, a is the crank radius, and θ is the intake air The valve closing timing, that is, the crank angle before TDC. It is clear that by delaying the intake valve closing time, the effective displacement of the engine is reduced and vice versa.

  During the HCCI + VVT mode, delaying the intake valve opening and closing timing results in a small effective compression ratio, which allows the generation of a homogeneous charge that can be ignited later by HCCI combustion when the piston is near TDC. Fuel can be injected with sufficiently low pressure in the cylinder, while additional energy input allows for increased load and / or higher speeds due to the increased fuel supply than in HCCI + RVT mode. Provided. However, the delay in closing the intake valve should not be so long that the ratio of air to fuel becomes too low.

  Engine control systems typically store a number of fuel delivery maps that correlate with various combinations of speed and load. Within the HCCI + RVT zone of FIG. 1, the map as a whole matches the zone 82 of FIG. 4A. Within the HCCI + VVT zone, the map as a whole matches the zone 84 of FIG. 4B. Within the CD + RVT zone, the map generally corresponds to zone 86 in FIG. 4C.

  When a cylinder is fueled to produce HCCI combustion in HCCI + RVT mode, the processing system utilizes a corresponding fuel delivery map that allows fuel to be consistent with zone 82 for a particular engine speed and engine load. Provide fuel supply parameters suitable for injection.

  If the cylinder is fueled to produce HCCI combustion in HCCI + VVT mode, the processing system utilizes one or more corresponding fuel delivery maps, such that the zone 84 and the engine load for a particular engine speed and engine load. Provides fuel supply parameters suitable for injecting fuel consistently.

  If the cylinder is fueled to produce CD combustion in CD + RVT mode, the processing system utilizes one or more corresponding fuel delivery maps, such that the zones 86 and 86 for a particular engine speed and engine load. Provides fuel supply parameters suitable for injecting fuel consistently.

  FIG. 5 is a graph showing the engine load on the vertical axis and the engine speed on the horizontal axis. At the origin of the graph, the engine load is zero and the engine speed is zero. Solid lines 100, 102, 104, and 106 define the boundaries of the four zones indicated as HCCI + RVT, HCCI + IVC, HCCI + IVC + EVC, and CD + RVT, respectively. RVT represents the regular valve timing of the engine intake valve, IVC represents the delay in closing the engine intake valve, and EVC represents the delay in closing the exhaust valve.

  Zone HCCI + RVT covers an area that includes various combinations of relatively low engine load and relatively low engine speed. Zone HCCI + IVC covers an area that includes various combinations of engine loads and engine speeds that are relatively higher than those of zone HCCI + RVT. Zone HCCI + IVC + EVC covers an area that includes various combinations of engine load and engine speed that are relatively higher than the engine load and engine speed of zone HCCI + IVC. Zone CD + RVT covers an area containing combinations including various areas of higher engine load and higher engine speed than the engine load and engine speed of zone HCCI + IVC + EVC.

  When a compression ignition engine is operating at a speed and load belonging to the zone HCCI + RVT, fuel is injected into the engine cylinder in a manner that causes HCCI combustion. When the engine is operating at a speed and load that belongs to either zone HCCI + IVC or HCCI + IVC + EVC, fuel is injected into the cylinder in a manner that causes HCCI combustion. When the engine is operating at a speed and load belonging to zone CD + RVT, fuel is injected into the cylinder in such a way as to cause CD combustion.

  In the HCCI + RVT mode, fuel is supplied to the engine and the valve is operated to produce HCCI combustion at an appropriate valve opening / closing timing called regular valve timing, ie RVT.

  In the HCCI + IVC mode, fuel is supplied to the engine and the intake valve is operated to cause HCCI combustion and reduce the effective compression ratio with the intake valve closing delayed more than the intake valve closing in the HCCI + RVT mode. Exhaust valve closure does not change much from RVT.

In HCCI + IVC + EVC mode, fuel is supplied to the engine, and the intake valve closing is delayed with respect to the intake valve closing in HCCI + RVT mode to reduce the effective compression ratio, and the exhaust valve closing causes the exhaust valve closing in HCCI + IVC mode. Operate to produce HCCI combustion in a delayed state as a reference. Over a range of engine speeds and engine loads where the engine is operating in HCCI + IVC mode, but lower than engine speeds and engine loads where the engine is operating in CD + RVT mode, the variable valve timing system is in HCCI + IVC mode. It operates to delay the closing timing of the exhaust valve as compared with the closing timing of the exhaust valve. By delaying the timing exhaust valve closing, reducing the proportion of residual hot gases in the cylinders, thereby reducing the cylinder temperature and pressure, thus reducing the certain engine emissions, such as of the NO _X Benefits are gained. Thereby, it is considered that the effective range of HCCI combustion can be extended.

  In the CD + RVT mode, fuel is supplied to the engine and the valve is operated as described above.

  FIG. 6 shows a flowchart 111 for the method of the present invention executed by the processing system of the ECU 66. Reference numeral 112 represents the start of processing executed by this method. In step 114, engine speed data and engine load data are processed to determine which of the four fuel delivery modes of FIG. 5 should be selected. One approach to selecting a mode is to provide one or more maps to the processing system to define the four zones shown in FIG. 5 and compare data values for instantaneous engine speed and engine load according to the maps. .

  If step 114 selects the HCCI + RVT mode, FIG. 6 shows that fuel is injected into each cylinder to cause HCCI combustion in all cylinders (reference number 116) at regular valve timing RVT (reference number 117). Show. This operation continues until completion, at which point the flowchart process is repeated.

  If step 114 selects the HCCI + IVC mode, FIG. 6 shows that fuel is injected into each cylinder to cause HCCI combustion in all cylinders (reference numeral 118), where the intake valve opening and closing timing is variable valve It is shown being delayed by the timing system 70 (reference numeral 119). This operation continues until completion, at which point the flowchart process is repeated.

  When step 114 selects the HCCI + IVC + EVC mode, FIG. 6 shows that fuel is injected into each cylinder to cause HCCI combustion in all cylinders (reference numeral 120). In this case, the intake valve opening timing and the exhaust valve opening / closing timing Both timings (reference number 121) indicate being delayed by the variable valve timing system 70. This operation continues until completion, at which point the flowchart process is repeated.

  If step 114 selects the CD + RVT mode, FIG. 6 shows that fuel is injected into each cylinder to cause CD combustion in all cylinders (reference numeral 122) at regular valve timing RVT (reference numeral 123). Show. This operation continues until completion, at which point the flowchart process is repeated.

  In both the HCCI + IVC mode and the HCCI + IVC + EVC mode, the fuel supply is increased relative to the fuel supply in the HCCI + RVT mode. For the HCCI + RVT mode, the general fuel supply map is approximately the same as in FIG. 4A, for the HCCI + IVC mode, the general fuel supply map is approximately the same as in FIG. 4B, and for the HCCI + IVC + EVC mode, the general fuel supply map. Is approximately the same as FIG. 4B, but slightly higher and wider than the HCCI + IVC mode fuel supply map, and for the CD + RVT mode, the general fuel supply map is approximately the same as FIG. 4C.

  CD fuel injection during an engine cycle may be described by that particular fuel supply pulse, for example, a pilot (preceding) injection pulse, a main injection pulse, and a post-injection pulse. Any particular fuel injection process will typically always have at least one main fuel injection pulse, and one or more pilot and / or post-injection pulses can be implemented, Whether or not to perform is arbitrary.

  The HCCI fuel supply may have one or more individual pulses.

The present invention has the following advantages.
1) The present invention can simultaneously reduce NO _x and soot.
2) The present invention has high thermal efficiency.
3) The present invention can cover the entire operating range of the engine.
4) The present invention can be used for large, medium and small diesel engines.
5) The present invention can be specifically configured with only the processor, provided that the processor has sufficient capacity, which makes the present invention extremely cost effective.

  While the presently preferred embodiment of the invention has been illustrated and described, it is to be understood that the principles of the invention apply to all embodiments that fall within the scope of the invention as set forth in the claims. .

A first embodiment of the present invention having an HCCI + RVT combustion mode for one speed and load condition, an HCCI + VVT combustion mode for another speed and load condition, and a CD + RVT combustion mode for another engine speed and load condition It is a typical graph figure of the fuel supply system by the principle of. 1 is a general schematic diagram of portions of an exemplary diesel engine suitable for certain principles of the present invention. 3 is a flowchart showing a scheme according to the first embodiment used in the engine of FIG. 2. It is a figure which shows the general fuel injection quantity by the general fuel supply map used about HCCI + RVT combustion. It is a figure which shows the general fuel injection quantity by the general fuel supply map used about HCCI + VVT combustion. It is a figure which shows the general fuel injection quantity by the general fuel supply map used about CD + RVT combustion. It is a graph similar to the graph of FIG. 1 regarding the 2nd Embodiment of this invention. It is a flowchart which shows the system by 2nd Embodiment utilized with an engine.

Claims (18)

A method of operating a compression ignition engine,
a) processing one particular data to select one of a plurality of fuel delivery modes for operating the engine;
b) If the first mode is selected, one or more combustion chambers are fueled to provide substantially homogeneous air and fuel charge in each of the combustion chambers during the corresponding engine cycle. Generating and compressing and self-igniting each of the charges, wherein no additional fuel is introduced after self-ignition during the corresponding engine cycle;
c) When the second mode is selected, the effective compression ratio of each of the combustion chambers is decreased with respect to the effective compression ratio for the first mode, and the combustion chamber for the fuel supply for the first mode. Supplying an increased amount of fuel to each of them to produce a substantially homogeneous charge of air and fuel in each of the combustion chambers during the corresponding engine cycle, compressing each of the charges to self-ignite, In this case, having the step of not introducing additional fuel after self-ignition during the corresponding engine cycle,
A method characterized by that. d) When the third mode is selected, the effective compression ratio for each of the combustion chambers is reduced in view of the effective compression ratio used during the first supply mode, and the supply fuel for the second mode is reduced. In contrast, an increased amount of fuel is supplied to each of the combustion chambers to produce substantially homogeneous air and fuel charges in each of the combustion chambers, and each of the charges is compressed and self-ignited, A step of preventing additional fuel from being introduced after self-ignition during the corresponding engine cycle and delaying the closing timing of the exhaust valve with respect to the closing timing of the exhaust valve during the second mode;
The method of claim 1. In both step c) and step d), the step of reducing the effective compression ratio for each of the combustion chambers as viewed from the effective compression ratio used during the first fuel supply mode comprises the first fuel Including the step of delaying the closing timing of the intake valve with respect to the closing timing of the intake valve during the supply mode,
The method of claim 2. e) If the fourth mode is selected, the fuel in the engine cycle is replaced when the air in the corresponding combustion chamber is sufficiently compressed to burn the fuel when introducing the fuel. Further comprising the step of fueling each of the combustion chambers by introducing at a point of time
The method of claim 2. In the graph showing the relationship between the engine speed and the engine load corresponding to the origin having the speed of 0 and the load of 0, step b) is the engine speed and the engine load in the first zone of the graph diagram in contact with the origin. Step c) occurs at the engine speed and engine load in the second zone bordering the first zone, and step d) is in the third zone bordering the second zone. Occurs at engine speed and engine load, step e) occurs at engine speed and engine load in a fourth zone bordering the third zone.
The method of claim 4. d) If the third mode is selected, the fuel in the engine cycle is either in the engine cycle when the air in the corresponding combustion chamber is sufficiently compressed to burn the fuel when introducing the fuel. Further comprising the step of fueling each of the combustion chambers by introducing at a point of time
The method of claim 1. In the graph showing the relationship between the engine speed and the engine load corresponding to the origin having the speed 0 and the load 0, step b) is the engine speed and the engine load in the first zone of the graph in which the origin is in contact with the boundary. Step c) occurs at the engine speed and engine load in the second zone bordering the first zone, and step d) is in the third zone bordering the second zone. Occurs at the engine speed and engine load of
The method of claim 6. Selecting the one of a plurality of fuel delivery modes to process certain data to operate the engine includes processing data representing engine load;
The method of claim 1. Selecting one of a plurality of fuel delivery modes to process certain data to operate the engine includes processing data representing engine speed;
The method of claim 8. A compression ignition engine,
A control system for processing the data;
One or more combustion chambers;
A fuel supply system for injecting fuel into the one or more combustion chambers;
The control system includes:
a) selecting one of a plurality of fuel delivery modes to process certain data and operate the engine;
b) If the first mode is selected, one or more combustion chambers are fueled to provide substantially homogeneous air and fuel charge in each of the combustion chambers during the corresponding engine cycle. Causing each of the charges to be compressed and self-ignited, in which case no additional fuel is introduced after the self-ignition during the corresponding engine cycle;
c) When the second mode is selected, the effective compression ratio of each of the combustion chambers is decreased with respect to the effective compression ratio for the first mode, and the combustion chamber for the fuel supply for the first mode. Supplying an increased amount of fuel to each of them to produce a substantially homogeneous charge of air and fuel in each of the combustion chambers during the corresponding engine cycle, compressing each of the charges to self-ignite, In this case, the fuel supply system is controlled by preventing additional fuel from being introduced after self-ignition during the corresponding engine cycle.
An engine characterized by that. d) When the third mode is selected, the system reduces the effective compression ratio for each of the combustion chambers in view of the effective compression ratio used during the first supply mode, and the second mode An increased amount of fuel is supplied to each of the combustion chambers relative to the fuel supplied for the mode to produce a substantially homogeneous air and fuel charge in each of the combustion chambers, and each of the charges is compressed to self By igniting, in this case, during the corresponding engine cycle, no additional fuel is introduced after self-ignition and by delaying the closing time of the exhaust valve relative to the closing time of the exhaust valve during the second mode, Controlling the fuel supply system;
The engine according to claim 10. When either the second mode or the third mode is selected, the control system delays the closing timing of the intake valve with respect to the closing timing of the intake valve during the first fuel supply mode. Reducing the effective compression ratio for each of the combustion chambers in view of the effective compression ratio used during the first fuel supply mode,
The engine according to claim 11. e) If the fourth mode is selected, the control system causes the fuel to flow when the air in the corresponding combustion chamber is sufficiently compressed to burn the fuel when the fuel is being introduced. Fueling each of the combustion chambers by introduction at some point during the engine cycle;
The engine according to claim 11. In the graph showing the relationship between the engine speed and the engine load corresponding to the origin having a speed of 0 and a load of 0, the first mode is defined by the first zone of the graph and bordering the origin and the second. The mode is defined by a second zone bordering the first zone, the third mode is defined by a third zone bordering the second zone, and the fourth mode Is defined by a fourth zone bordering the third zone and the boundary,
The engine according to claim 13. d) If the third mode is selected, the control system causes the fuel to flow when the air in the corresponding combustion chamber is sufficiently compressed to burn the fuel when introducing the fuel. Fueling each of the combustion chambers by introduction at some point during the engine cycle;
The engine according to claim 10. In the graph showing the relationship between the engine speed and the engine load corresponding to the origin having a speed of 0 and a load of 0, the first mode is defined by the first zone of the graph and bordering the origin and the second. The mode is defined by a second zone bordering the first zone, and the third mode is defined by a third zone bordering the second zone,
The engine according to claim 15. Selecting one of a plurality of fuel delivery modes for processing certain data to operate the engine includes processing data representing engine load.
The engine according to claim 10. Selecting one of a plurality of fuel delivery modes for processing certain data to operate the engine includes processing data representing engine speed.
The engine according to claim 10.

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