JP3661762B2 - Starter for in-cylinder injection internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a starter used in a cylinder injection type internal combustion engine (hereinafter referred to as an engine) capable of directly injecting fuel into a cylinder.
[0002]
[Related background]
In recent years, in-cylinder injection engines that inject fuel directly into a cylinder have been put into practical use in order to achieve emission reduction and fuel efficiency improvement. In this type of engine, fuel is injected in the intake stroke to form a uniform mixture in the cylinder, and fuel is injected in the compression stroke, so that the mixture near the stoichiometric air-fuel ratio is around the spark plug. And the stratified combustion that achieves a super lean overall air-fuel ratio can be switched. The operating region in which stratified combustion is possible is generally limited to low rotation and low load. For example, in the engine described in Japanese Patent Application Laid-Open No. 10-30468, stratified combustion is executed by compression stroke injection from the start.
[0003]
[Problems to be solved by the invention]
As described above, the engine described in the publication performs stratified combustion at start-up in order to obtain the advantages of stratified combustion and fuel efficiency from the start-up. Therefore, the control procedure at the time of starting is the same as that of a normal engine. First, cylinder discrimination is performed by starting cranking, and when any cylinder reaches the compression stroke after completion of the cylinder discrimination, a predetermined process is performed for the cylinder. Fuel injection is executed with the injection amount and the injection timing. In other words, the engine described in the publication does not consider any shortening of the required start time, and cannot satisfy this demand.
[0004]
In view of this, the present applicant has proposed an early start control in a cylinder injection engine capable of directly injecting fuel into a cylinder, in which fuel is injected into a cylinder stopped in the compression stroke and immediately subjected to an initial explosion. Application No. 11-73362). This early start control utilizes the fact that the in-cylinder pressure and temperature rise when the piston of the cylinder in the compression stroke rises due to cranking, and the conditions that can be ignited are set, but depending on the operating state of the engine The fuel injected into the cylinder in the compression stroke may self-ignite before normal spark ignition, or the combustion rate may increase due to the progress of the precursor reaction. Under such circumstances, there is a problem that problems such as increased engine vibration, knock noise, or the entry of carbon into the nozzle of the fuel injection valve exposed in the cylinder arise.
[0005]
An object of the present invention is to provide a direct injection internal combustion engine that can quickly complete a start, reliably perform normal spark ignition at the start, and prevent problems caused by self-ignition and rapid combustion. It is to provide a starting device.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, there is provided a starter for a direct injection internal combustion engine capable of directly injecting fuel into a cylinder, wherein the internal combustion engine is stopped.Compression stroke cylinderPiston position detecting means for detecting the piston position, and at the start of the internal combustion engineThe start-up injection control means for executing fuel injection for the remaining compression stroke of the compression stroke cylinder, and the compression stroke detected by the piston position detection means at the time of fuel injection into the compression stroke cylinder by the start-up injection control means CylinderControl amount variable means for varying at least one of the fuel injection amount to the cylinder, the fuel injection timing, and the ignition timing in a direction to suppress self-ignition and combustion speed according to the piston position is provided. Therefore, when cranking is started for starting, the internal combustion engineCompression processcylinderRemaining compression strokeIn response to this, fuel injection is performed, and an initial explosion is quickly performed by ignition. At least one of the fuel injection amount, the fuel injection timing, and the ignition timing at this time is set in a direction to suppress self-ignition and the combustion speed, so that normal spark ignition is reliably performed.
  According to the second aspect of the present invention, when the subsequent intake stroke cylinder (cylinder stopped in the intake stroke) reaches the compression stroke following the fuel injection to the compression stroke cylinder, the start-up injection control means changes to the intake stroke cylinder. In addition to executing fuel injection, the control amount varying means suppresses self-ignition or combustion speed of at least one of the fuel injection amount, fuel injection timing, and ignition timing to the cylinder according to the piston position of the intake stroke cylinder. The direction is variable. Therefore, even when fuel injection is performed on the intake stroke cylinder following the compression process cylinder, at least one of the fuel injection amount, the fuel injection timing, and the ignition timing is set to suppress self-ignition and combustion speed. Normal spark ignition.
[0007]
  Claims3In the present invention, the control amount varying means is configured to increase the fuel injection amount as the stopped piston position approaches the bottom dead center. For example, for a cylinder that is stopped in the compression stroke, the closer the piston position is to the bottom dead center, the greater the pressure rise when compressed, which facilitates self-ignition and rapid combustion. As for the cylinder, as the piston position is closer to the bottom dead center, the amount of residual gas in the cylinder increases and the amount of intake from the intake port decreases, so that self-ignition becomes easier. And since the amount of fuel injection increases according to these tendencies, self-ignition is prevented by fuel cooling.
[0008]
  Further claims4In the present invention, the control amount varying means is configured to retard the ignition timing as the stopped piston position approaches the bottom dead center. For example, for a cylinder that is stopped in the compression stroke, the combustion speed (combustion speed relative to the crank angle) increases because the pressure rises when the piston is closer to the bottom dead center, and also stops in the intake stroke. For the middle cylinder, the closer the piston position is to the bottom dead center, the greater the amount of residual gas in the cylinder and the smaller the amount of intake air from the intake port. Therefore, the in-cylinder temperature during compression increases and the combustion speed increases. Since the ignition timing is retarded in accordance with these tendencies, the in-cylinder pressure after ignition is reduced, and the combustion speed is suppressed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a starter for a direct injection type engine used in an idle stop vehicle will be described.
In the overall configuration diagram of FIG. 1, reference numeral 1 denotes an in-cylinder injection type gasoline engine, which is configured as a four-cycle in-line four-cylinder that explodes at regular intervals every 180 ° CA. The combustion chamber, intake system, etc. of the engine 1 are designed exclusively for in-cylinder injection. A spark plug 2 is attached to each cylinder, and a fuel injection valve 3 is attached so that fuel can be directly injected into the cylinder. Yes.
[0010]
A manual transmission 4 is connected to the engine 1, and this transmission is connected to driving wheels of the vehicle via a differential gear (not shown). A clutch 5 is provided between the engine 1 and the transmission 4, and this clutch 5 controls power transmission from the engine 1 side to the transmission 4 side in accordance with a clutch operation by the driver. The engine 1 is provided with a constantly meshing starter 6, and the pinion gear 6 a of the starter 6 is always in mesh with the flywheel 1 a of the engine 1. The flywheel 1a is provided with a one-way clutch (not shown). The one-way clutch transmits the driving force of the starter 6 to the engine 1 side at the time of start-up, performs cranking, and idles after the start-up is completed. Thus, the starter 6 is prevented from being reversely driven.
[0011]
The starter 6 is connected to the battery 11 via an ignition switch (not shown), and is connected to the battery 11 via a relay contact 12 a of the starter control controller 12. Accordingly, the starter 6 is energized in accordance with the operation of the ignition switch as in the normal case, and also energized when the relay contact 12a is closed by the excitation of the relay coil 12b of the starter control controller 12.
[0012]
In the vehicle compartment, an input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) used for storing control programs and control maps, a central processing unit (CPU), an ECU 21 (engine) provided with a timer counter, etc. Control unit) is installed. On the input side of the ECU 21, an engine temperature sensor 22 that detects the temperature T of the engine 1, a crank angle sensor 23 that outputs a crank angle signal as the crankshaft of the engine 1 rotates, and a TOP signal that accompanies the rotation of the camshaft. A cam angle sensor 24 that outputs a vehicle speed, a vehicle speed sensor 25 that detects a vehicle speed V, a clutch sensor 26 that detects an operation state of the clutch 5, an accelerator sensor 27 that detects an accelerator operation amount Acc, and a shift that detects a shift position of the transmission 4. The position sensor 28 and other various switches and sensors are connected.
[0013]
Further, the ignition plug 2 and the fuel injection valve 3 are connected to the output side of the ECU 21, and the relay coil 12 b of the starter control controller 12 is connected. The ECU 21 executes various controls for operating the engine 1 including fuel injection control and ignition timing control based on each detection information described above, and executes an automatic stop start process of the engine 1 when the vehicle is stopped such as waiting for a signal. . Further, when the engine is started, the ECU 21 executes a start-only control to start early.
[0014]
In the in-cylinder injection engine 1 configured as described above, the fuel is injected in the compression stroke in addition to the uniform combustion in which the fuel is injected in the normal intake stroke to form a uniform mixture in the cylinder. It enables stratified combustion with a lean overall air-fuel ratio. The stratified combustion is generally executed in an operating region of low rotation and low load. The ECU 21 calculates the target average effective pressure Pe (representing the engine load) obtained from the accelerator operation amount Acc detected by the accelerator sensor 27, and the crank angle sensor 23. The compression stroke injection is executed in a region where the engine rotational speed Ne obtained from the crank angle signal of the engine is relatively low, the emission reduction and the fuel consumption improvement are achieved, and the intake stroke injection is executed in a region beyond that, which is required. Ensure engine torque.
[0015]
Next, the automatic stop start process of the engine 1 unique to the idle stop vehicle will be described.
The ECU 21 automatically stops the engine 1 when a preset engine stop condition is satisfied when the traveling vehicle stops due to a signal or the like, and also automatically starts the engine 2 when a preset engine start condition is satisfied. This prevents emission emission and fuel consumption while the vehicle is stopped. The engine stop condition is that the vehicle speed V detected by the vehicle speed sensor 25 is zero, the depression operation of the clutch 5 is not detected by the clutch sensor 26 (clutch engagement state), and the shift position sensor 28 When the detected shift position is set to the N (neutral) position and these conditions are satisfied, the ECU 21 determines that the engine stop condition is satisfied and stops the fuel injection control and the ignition timing control. Then, the engine 1 is stopped.
[0016]
Further, as engine start conditions, it is set that the clutch sensor 26 detects that the clutch 5 is depressed (clutch disengaged state) and that the shift position detected by the shift position sensor 28 is the N position. When these conditions are satisfied, the ECU 21 determines that the engine start condition is satisfied, excites the relay coil 12b of the starter control controller 12, and restarts the fuel injection control and the ignition timing control. Since the relay contact 12a is closed by the excitation of the relay coil 12b, the starter 6 is energized to perform cranking, and can start when the engine 1 is started.
[0017]
In either case of automatic engine stop by the above control and manual stop by normal ignition switch OFF operation, the ECU 21 first stops fuel injection control according to an engine stop routine (not shown), and then operates the engine 1. After two strokes have elapsed in the cycle, the fuel that has already been injected into the cylinder is burned, and then the ignition timing control is stopped.
[0018]
Next, the start control executed by the starter of the direct injection type engine 1 configured as described above will be described.
The ECU 21 executes the engine start routine shown in FIG. 2 when the start condition is satisfied during the engine automatic stop such as waiting for a signal or when the ignition switch is ST-operated by the driver and cranking is started. . First, the ECU 21 reads, from the storage device, information on a cylinder (hereinafter referred to as a compression stroke cylinder) in the compression stroke of the engine 1 stopped in step S2 and information on the piston position P of the cylinder. Since any cylinder is always positioned in the compression stroke in the 4-cycle in-line four cylinders, the compression stroke cylinder is always specified at this time, and the compression reaction force is received at the compression top dead center. To concentrate around BTDC 90 ° CA.
[0019]
The information regarding the compression stroke cylinder and the piston position P is calculated based on the crank angle signal detected by the crank angle sensor 23 and the TOP signal detected by the cam angle sensor 24 immediately before the engine is stopped. Of course, while the engine is automatically stopped, it is kept in the storage device even during parking when the ignition switch is turned OFF. In the present embodiment, the crank angle sensor 23, the cam angle sensor 24, and the ECU 21 when executing the process of step S2 function as piston position detecting means.
[0020]
Next, the ECU 21 reads the engine temperature T detected by the engine temperature sensor 22 in step S4, and determines in step S6 whether or not early start control can be executed for the current compression stroke cylinder. As described below, the early start control is a process in which fuel is injected into a compression stroke cylinder or the like and ignited to immediately start an initial explosion. To achieve this, the temperature for vaporizing the fuel, For example, if the temperature of the gas remaining in the compression stroke cylinder is low, or if the piston position P cannot be compressed almost at the top dead center, the pressure will be increased due to misfire. I can't get an explosion. Therefore, in step S6, the determination is made based on, for example, whether the engine temperature T correlated with the in-cylinder gas temperature and the piston position P are within the ignitable region according to the map of FIG. Even under the same conditions, the ease of ignition varies depending on the octane number of the gasoline used, so maps having different characteristics may be used depending on the gasoline used.
[0021]
Here, when the engine 1 is automatically stopped by waiting for a signal or the like, the temperature of the engine itself has increased due to the operation immediately before, so that the in-cylinder gas temperature has sufficiently increased due to heat transfer from the cylinder wall surface or the like. Further, as described above, since the piston position P when the engine is stopped concentrates with a high probability around BTDC 90 ° CA, in most cases, the determination in step S6 is YES, assuming that it falls within the ignitable region.
[0022]
When the determination in step S6 is NO, the normal start control in which fuel is injected in the intake stroke as in the normal engine is set as the start mode in step S8, and the fuel injection amount is set based on the cooling water temperature of the engine 1 in step S10. In step S12, the injection timing is similarly determined based on the cooling water temperature or the like, the ignition timing is set in step S14, and the start control is executed in step S16 based on these pieces of information. At this time, cranking is started in the case of automatic starting (not necessary because cranking has already started in the case of starting by the driver's ST operation), and the cylinder that reaches the first intake stroke after cranking is started. In contrast, fuel injection and ignition are performed.
[0023]
Next, in step S18, it is determined whether or not the engine rotational speed Ne is equal to or higher than a preset complete explosion determination value N0. If NO, it is considered that the engine has not been started yet, and the process returns to step S6 to repeat the process. If this determination is YES, this routine is terminated. After that, the routine shifts to normal engine control and selects compression stroke injection or intake stroke injection based on the target average effective pressure Pe and the engine rotational speed Ne. For example, when the idle operation is continued, the compression stroke injection is performed. In the case of rapid acceleration, the intake stroke injection is set, and control is performed by determining the fuel injection amount, injection timing, and ignition timing according to each operation state.
[0024]
When the determination in step S6 is YES, the early start control is set as the start mode in step S20, the fuel injection amount is determined in step S22, the injection timing is determined in step S24, and the ignition timing is determined in step S26. Based on these pieces of information, start control is executed for the compression stroke cylinder in step S16. The fuel injection amount, injection timing, and ignition timing at this time are different from those in the normal start control described above, and are determined as follows.
[0025]
First, determination of the fuel injection amount and the injection timing will be described. As a premise, even if the engine temperature T and the piston position P are within the ignition possible region as described above, the precursor reaction of the injected fuel proceeds by the compression pressure before ignition by the spark plug 2 and self-ignition. In this case, effective torque is not generated, and engine vibration and knock noise are caused. 4 to 7 are characteristic diagrams showing the combustion state of the compression stroke cylinder when starting at each piston position P (BTDC 180 ° CA, BTDC 120 ° CA, BTDC 90 ° CA, BTDC 60 ° CA). As is clear from the comparison of the drawings, the tendency of self-ignition becomes more prominent as the piston position P is closer to the bottom dead center (BTDC 180 ° CA). This is because the conditions under which the precursor reaction is likely to proceed are met due to an increase in pressure when compressed and a longer time until ignition.
[0026]
As can be seen from FIG. 4, for example, the fuel injection amount is increased relatively so as to achieve fuel cooling, and normal spark ignition is more easily performed. As is clear from FIGS. 4 to 7, the injection timing varies depending on the piston position P. Since this feature varies depending on the engine, maps corresponding to various engines are set in advance.
[0027]
Therefore, when starting from each piston position P, the fuel injection amount and the injection timing are set at, for example, point A in the spark ignition region shown in the corresponding figure. However, as the condition of the point A related to the injection timing, it is necessary to set it on the retard side from the valve closing timing (for example, BTDC 140 ° CA) of the intake valve as shown in FIG. This is the same even if the area of the spark spark ignition is expanded from the valve closing timing to the advance side, and the substantial compression starts after the intake valve is closed, and This is a condition determined from the fact that a fuel injection causes a problem that the injected fuel flows backward. Since the piston position P concentrates around BTDC 90 ° CA as described above, the piston position P of BTDC 90 ° CA in FIG. 6 occurs frequently, and conversely, the preceding cylinder has a compression reaction force at the compression top dead center. The piston position P and the like of BTDC 180 ° CA in FIG.
[0028]
On the other hand, even if the piston position P is the same, the higher the engine temperature T, the easier it is to ignite, so the characteristics of FIGS. 4 to 7 differ depending on the engine temperature T. Therefore, for example, when the engine temperature T is high, it is necessary to deal with the point A by shifting the fuel injection amount to the increasing side and shifting the injection timing in the direction according to the engine characteristics.
[0029]
Similarly, even if the piston position P is the same, the lower the octane number of the gasoline used, the easier it is to ignite, so the characteristics shown in FIGS. 4 to 7 differ depending on the gasoline used. Therefore, for example, when using regular gasoline that easily ignites, it is necessary to take measures by shifting the point A to the fuel injection amount increasing side and to the retarding side of the injection timing.
Therefore, it is necessary to determine the fuel injection amount and the injection timing according to the above-described piston position P, engine temperature T, and gasoline used G. In Step S22 and Step S24, these characteristics (for example, FIG. 4 to FIG. The fuel injection amount and the injection timing are determined from the map set based on the characteristic 7). In addition, it is not always necessary to consider all these three types of elements. For example, the setting corresponding to the gasoline G used may be omitted.
[0030]
On the other hand, regarding the ignition timing, FIG. 8 shows the influence of the ignition timing on the crank angular velocity and the engine vibration. As shown in this figure, the engine vibration is rapidly suppressed on the retard side from the compression top dead center. In addition, it can be seen that a relatively high crank angular velocity is obtained, and the combustion pressure is efficiently converted into crank rotation. Therefore, for example, the ignition timing is set in a range of about ATDC 0 ° to 15 ° CA, and a map associated with the above three types of elements (piston position P, engine temperature T, used gasoline G) is created. In step S26, In a situation where rapid combustion is likely to occur (a situation where the piston position P is low and the in-cylinder pressure becomes high at normal ignition timing and rapid combustion is likely to occur), the ignition timing is retarded to the ATDC 15 ° CA side where the in-cylinder pressure has decreased. Conversely, the ignition timing is set to the ATDC 0 ° CA side in a situation where rapid combustion is difficult (a situation where the piston position P is high and the in-cylinder pressure is not so high even at the normal ignition timing). It should be noted that the cylinder is preferably set on the ATDC side for cylinders that start near the bottom dead center or from the intake stroke.
[0031]
Then, based on these pieces of information, start control is executed for the compression stroke cylinder in step S16. When the determination in step S18 is YES, this routine is ended and the routine shifts to normal engine control. Immediately after the transition from the start control to the normal control, it may be set to temporarily execute the compression stroke injection regardless of the operation state, so as to prevent the engine 1 from being blown up unnecessarily.
[0032]
Further, when the determination in step S18 is NO and the start-up is not completed, the second stroke following the compression stroke cylinder first subjected to the above-described explosion is performed in steps S22 to S26 through steps S6 and S20. Similar control is performed on the cylinder, that is, the cylinder that was in the intake stroke when the engine was stopped (hereinafter referred to as the intake stroke cylinder). However, since this intake stroke cylinder differs from the compression stroke cylinder in the following points, the fuel injection amount, injection timing, and ignition timing are determined according to a map set in consideration of the difference. Has been decided.
[0033]
In contrast to the compression stroke cylinder that starts compression in the middle of the compression stroke, the intake stroke cylinder always starts compression from the bottom dead center. Therefore, the auto-ignition region does not change (as shown in FIGS. 4 to 7) due to the difference in the compression state corresponding to the piston position P as in the compression stroke cylinder. It can be said that it is not necessary to consider the piston position P for setting the timing. However, since the intake stroke cylinder when the engine is stopped is in the middle of the intake stroke, combustion is performed in a state where the residual gas already present in the cylinder is mixed with the low-temperature intake air in the intake port. The in-cylinder gas temperature after mixing changes in accordance with the amount of residual gas when the engine is stopped, in other words, the piston position P of the intake stroke cylinder, and accordingly, the ease of self-ignition and rapid combustion changes. .
[0034]
9 and 10 are characteristic diagrams showing the combustion state of the intake stroke cylinder when starting at each piston position P (the compression stroke cylinder is BTDC 180 ° CA, BTDC 90 ° CA). As shown in FIG. 9, when the piston position P of the intake stroke cylinder is at the top dead center, the residual gas is roughly 0% and the intake air is 100%. As a result, the in-cylinder gas temperature is lowered and self-ignition or rapid No burning occurs. Also, as the piston position P of the intake stroke cylinder approaches the bottom dead center, the residual gas changes in the increasing direction and the intake air decreases in the decreasing direction, so that the in-cylinder gas temperature rises and self-ignition and rapid combustion occur. It becomes easy to do. For example, as shown in FIG. 10, when the piston position P of the intake stroke cylinder is in the middle of the intake stroke, the self-ignition region occupies most due to the rise of the in-cylinder gas temperature.
[0035]
That is, in this intake stroke cylinder, the in-cylinder gas temperature is not simply correlated with the engine temperature T and is affected by the piston position P, so that the in-cylinder gas temperature is reflected in the fuel injection amount and the injection timing. It is necessary to consider P. Therefore, in step S22 and step S24, the map set based on the piston position P (for example, the characteristics of FIGS. 9 and 10), the engine temperature T, and the gasoline G used (of course, the characteristics differ from the map of the compression stroke cylinder). ) To determine the fuel injection amount, injection timing and ignition timing.
[0036]
  When the intake stroke cylinder reaches the compression stroke, start control is executed in step S16 based on these pieces of information. In most cases, the start-up is completed by the combustion of the compression stroke cylinder and the intake stroke cylinder, and the ECU 21 determines YES in step S18 and ends the routine. If the start is not completed yet, the process returns to step S6. However, as long as the conditions for the early start are satisfied in step S6, the early start control is executed for the third and fourth cylinders by the process after step S20. A continuous start is attempted. In these cylinders, the intake air becomes 100%, and the engine speed Ne has already increased to some extent, so that the possibility of self-ignition becomes lower. And in this embodiment, the aboveECU21 when performing the process of step S16 functions as a starting injection control means,The ECU 21 when executing the processing from step S22 to step S26 functions as a control amount varying means.
[0037]
As is clear from the above description, in the starting device for the engine 1 of the present embodiment, fuel injection and ignition are immediately executed for the compression stroke cylinder and the intake stroke cylinder of the engine 1 that is stopped. A bomb can be started. Therefore, of course, in the case of starting by the driver's operation, even when the engine 1 stopped by waiting for a signal or the like is automatically started, the starting can be completed almost instantly and the vehicle can be started quickly, and as a result The commercial value of the stop vehicle can be improved.
[0038]
Moreover, based on the piston position P, the engine temperature T, and the gasoline G used, which correlate with the ease of self-ignition as described above, the fuel injection amount is increased and the ignition timing is retarded in the situation where self-ignition is likely to occur. The injection timing is set on a map specific to the engine. Therefore, the engine 1 can be started by reliably performing normal spark ignition, and troubles caused by the self-ignition, for example, increase in engine vibration, knocking noise, or the entry of carbon into the nozzle of the fuel injection valve 3, etc. It can be prevented in advance.
[0039]
This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the starter of the direct injection engine 1 used for the idle stop vehicle is embodied, but the starter of the direct injection engine used for a normal vehicle or the direct injection type used for the hybrid vehicle. It may be embodied as an engine starting device.
[0040]
In the above-described embodiment, the in-cylinder in-cylinder gasoline engine 1 is embodied as an in-line four cylinder. However, the cylinder arrangement is not limited to this, and for example, the in-line three-cylinder engine or the V-type six-cylinder engine is embodied. May be.
Further, in the above embodiment, the early start control is executed after determining whether or not the ignition is possible based on the engine temperature T and the piston position P. However, this determination is not necessarily performed. The early start control may be executed unconditionally for the intake stroke cylinder, and may be switched to the normal start control if the start is not started.
[0041]
On the other hand, in the above-described embodiment, the early start control is executed for both the compression stroke cylinder and the intake stroke cylinder. For example, for the compression stroke cylinder, the start control is not performed, and the subsequent intake stroke cylinder is not executed. Early start control may be executed.
[0042]
【The invention's effect】
As described above, according to the starter for a direct injection internal combustion engine of the present invention, the start can be completed quickly, and normal spark ignition is reliably performed at the start, which is caused by self-ignition or rapid combustion. It is possible to prevent problems such as an increase in engine vibration, the occurrence of knocking noise, or the entry of carbon into the injection port of the fuel injection valve.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a starter for a direct injection type engine according to an embodiment.
FIG. 2 is a flowchart showing an engine start routine executed by an ECU.
FIG. 3 is an explanatory diagram showing a map for determining an ignitable region.
FIG. 4 is a characteristic diagram showing a combustion state of a compression stroke cylinder when the piston position is started at BTDC 180 ° CA.
FIG. 5 is a characteristic diagram showing a combustion state of a compression stroke cylinder when the piston position is started at BTDC 120 ° CA.
FIG. 6 is a characteristic diagram showing a combustion state of a compression stroke cylinder when the piston position is started at BTDC 90 ° CA.
FIG. 7 is a characteristic diagram showing a combustion state of a compression stroke cylinder when the piston position is started at BTDC 60 ° CA.
FIG. 8 is an explanatory diagram showing the influence of ignition timing on crank angular velocity and engine vibration.
FIG. 9 is a characteristic diagram showing a combustion state of the intake stroke cylinder when the piston position of the compression stroke cylinder is started at BTDC 180 ° CA.
FIG. 10 is a characteristic diagram showing the combustion state of the intake stroke cylinder when the piston position of the compression stroke cylinder is started at BTDC 90 ° CA.
[Explanation of symbols]
1 engine (internal combustion engine)
21 ECU (piston position detection means, control amount variable means)
23 Crank angle sensor (piston position detection means)
24 Cam angle sensor (piston position detection means)

Claims (4)

In the in-cylinder injection internal combustion engine starter capable of injecting fuel directly into the cylinder,
Piston position detecting means for detecting the piston position of the compression stroke cylinder of the internal combustion engine being stopped;
Start-up injection control means for executing fuel injection for the remaining compression stroke of the compression stroke cylinder when the internal combustion engine is started ;
When fuel is injected into the compression stroke cylinder by the start-up injection control means , the fuel injection amount, fuel injection timing, and ignition timing of the cylinder according to the piston position of the compression stroke cylinder detected by the piston position detection means are determined. And a control amount varying means for varying at least one in a direction to suppress self-ignition or combustion speed. When the subsequent intake stroke cylinder reaches the compression stroke following the fuel injection to the compression stroke cylinder, the start-up injection control means performs fuel injection to the intake stroke cylinder, and the control amount varying means 2. The method according to claim 1, wherein at least one of a fuel injection amount, a fuel injection timing, and an ignition timing to the cylinder is varied in a direction to suppress self-ignition or combustion speed according to a piston position of the intake stroke cylinder. A starter for a direct injection internal combustion engine according to claim 1.   2. The starter for a direct injection internal combustion engine according to claim 1, wherein the control amount varying means increases the fuel injection amount as the stopped piston position approaches the bottom dead center.   2. The starter for a direct injection internal combustion engine according to claim 1, wherein the control amount varying means retards the ignition timing as the stopped piston position approaches the bottom dead center.

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