JP4770787B2 - Control device for vehicle engine - Google Patents

Description

  The present invention relates to a vehicular engine control device that automatically stops an engine when a predetermined automatic stop condition is satisfied, and then automatically restarts the engine when a predetermined restart condition is satisfied.

  In this type of engine control device, the intake stroke cylinder during the stop, which is in the intake stroke at the time of automatic stop, tends to have a high intake air temperature during the forced restart, and the self-intake cylinder before the compression top dead center is exceeded during the compression stroke. It is in a situation where it is easy to cause autoignition and pre-ignition.

Therefore, for example, Patent Document 1 discloses that when the intake stroke of the stop-time intake stroke reaches the first compression stroke, fuel is injected into the intake stroke cylinder of the stop-time, and self-ignition and pre-ignition in the compression stroke of the stop-time intake stroke cylinder. Some have been proposed to avoid this.
JP-A-2005-180208

  By the way, as a result of studying the prevention of pre-ignition in the intake stroke cylinder at the time of stop by the present inventors, it has been found that different measures are required depending on the stop position of the piston when the restart condition is satisfied.

  That is, when the piston stop position of the intake stroke cylinder at the time of stop is extremely on the bottom dead center side, the amount of air is large. Therefore, even if the air-fuel ratio is made rich by fuel injection, pre-ignition can be sufficiently prevented. Can not. On the other hand, when the piston stop position of the intake stroke cylinder at the time of stop is on the top dead center side, there is a problem that smoke can be easily generated although pre-ignition can be prevented.

  The present invention has been made in view of the above problems, and when restarting an engine that has been automatically stopped, avoiding problems in the intake stroke cylinder during stop according to the stop position of the piston when the restart condition is satisfied. An object of the present invention is to provide a vehicular engine control device that can be used.

In order to solve the above-described problems, the present invention provides a vehicle engine that automatically stops an engine when a predetermined automatic stop condition is satisfied and restarts the engine after the automatic stop when a predetermined restart condition is satisfied. The control apparatus includes a piston position determination unit that determines a piston stop position when the engine is automatically stopped, and a combustion control unit that controls engine combustion based on the determination of the piston position determination unit. The combustion control unit performs fuel injection and ignition on at least one of a stop-time expansion stroke cylinder that is in an expansion stroke at the time of automatic stop and a stop-time compression stroke cylinder that is in a compression stroke at the time of automatic stop. The injection control is performed for the stop-time intake stroke cylinder that is sometimes in the intake stroke. In a first stop range where the piston stop position of the intake stroke cylinder is within a predetermined range from bottom dead center, fuel supply to the intake stroke cylinder during stop is stopped, and predetermined from the top dead center side than the first stop range. In the second stop range that is within the range, at least part of the fuel, which is set at a constant amount regardless of the piston stop position, is injected in a plurality of times and is injected at a top dead center that is higher than the second stop range. in a third stop range from the side to the top dead center, the second than a certain amount of fuel which is set in the stop range all SANYO for injecting a small amount of fuel, the piston stop of the stop-state intake-stroke cylinder When the position is at least in the second and third stop ranges, the combustion control unit retards the ignition timing until after the compression top dead center has elapsed, and the piston stop position is in the second stop range. ignition Retard amount of the period is a control device for a vehicle engine, characterized in that it is set larger than the retard amount of time in said third stop range.

  In this aspect, suitable fuel supply is executed according to the piston stop position. That is, in the first stop range, the amount of air in the cylinder that is received during the automatic engine stop is large, and therefore the method of enriching the air-fuel ratio by fuel injection cannot sufficiently prevent preignition, so the fuel supply is stopped. By doing so, pre-ignition is surely prevented. Further, in the second stop range, fuel is dividedly injected into the intake stroke cylinder at the stop, so that the cooling effect due to the latent heat of vaporization and the occurrence of pre-ignition can be suppressed while preventing smoke and combustion. Time can be shortened, and high output and fuel consumption can be improved. Further, since the air-fuel ratio is corrected to the lean side in the third stop range, it is possible to suppress the occurrence of smoke due to an unnecessary increase in fuel.

Furthermore, in the above aspect, pre-ignition in the intake stroke cylinder at the time of stop can be more effectively suppressed. That is, when the intake stroke cylinder at the time of stop is stopped in the second stop range, the amount of air in the cylinder that is received during the automatic stop of the engine is larger than when it is stopped in the third stop range. . Therefore, as in the above aspect, the ignition timing in the second stop range is retarded further than the ignition timing in the third stop range, thereby ensuring startability according to the piston stop position. Self-ignition can be prevented.

  In a preferred aspect, when the piston stop position of the stop-time intake stroke cylinder is located at a boundary portion between the second stop range and the third stop range, the combustion control unit increases toward the top dead center side. The fuel injection amount is reduced.

  In a preferred embodiment, the electric drive device capable of assisting start-up of the stopped engine and the electric drive device are driven when a predetermined assist condition based on the determination of the piston position determination unit is satisfied when the restart condition is satisfied. An electric drive device control unit that drives the electric drive device at least when the piston stop position of the intake stroke cylinder at the time of stop is in the first stop range. . In this aspect, the engine driving force can be secured by the electric drive device when the stop-time intake stroke cylinder is stopped in the first range.

  As described above, according to the present invention, suitable fuel supply is executed in accordance with the stop position of the piston when the restart condition is satisfied, and problems such as smoke can be avoided while preventing pre-ignition. There is a remarkable effect.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  1 and 2 show a schematic configuration of a vehicle engine 1 according to the present invention.

  The engine 1 shown in each figure is a 4-cycle spark ignition gasoline engine, and is provided with four cylinders 12A to 12D (see FIG. 2). Further, in each of the cylinders 12A to 12D, a piston 13 connected to the crankshaft 3 by a connecting rod (not shown) is fitted, so that a combustion chamber 14 is formed above the piston 13. The pistons 13 provided in the cylinders 12A to 12D are configured to move up and down as the crankshaft 3 rotates with a predetermined phase difference.

  In general, in a multi-cylinder four-cycle engine, each cylinder performs a combustion cycle including intake, compression, expansion, and exhaust strokes with a predetermined phase difference. In the case of the four-cylinder engine of the present embodiment, the first cylinder 12A, the second cylinder 12B, the third cylinder 12C, and the fourth cylinder 12D from the one end side in the cylinder row direction are referred to as the first cylinder (# 1) and the third cylinder. (# 3) Combustion is performed with a phase difference of 180 degrees in crank angle in the order of the fourth cylinder (# 4) and the second cylinder (# 2). Further, in this embodiment, a cylinder that was in the compression stroke during the automatic engine stop is referred to as a stop compression stroke cylinder, and a cylinder that was in the expansion stroke is referred to as a stop expansion stroke cylinder (similarly, the cylinder that was in the intake stroke is stopped). The cylinder in the intake stroke and the exhaust stroke is referred to as a stop exhaust stroke cylinder).

  The cylinder head 10 is provided with a spark plug 15 disposed at the top of the combustion chamber 14 of each of the cylinders 12 </ b> A to 12 </ b> D so that the plug tip faces the combustion chamber 14. Further, the cylinder head 10 is provided with a fuel injection valve 16 that directly injects fuel from the side of the combustion chamber 14 to the inside. The fuel injection valve 16 includes a needle valve and a solenoid (not shown), and is driven and opened for a time corresponding to the pulse width of the pulse signal input from the combustion control unit 101 (see FIG. 3) of the engine control unit 100. The fuel is injected to the vicinity of the electrode of the spark plug 15 in an amount corresponding to the valve opening time.

  In addition, an intake port 17 and an exhaust port 18 that open toward the combustion chamber 14 are provided in the upper portions of the cylinders 12A to 12D. In addition, an intake valve 19 and an exhaust valve 20 are respectively provided at a connection portion between the ports 17 and 18 and the combustion chamber 14. An intake passage 21 and an exhaust passage 22 are connected to the intake port 17 and the exhaust port 18. As shown in FIG. 2, the downstream side of the intake passage 21 close to the intake port 17 branches into an independent branch intake passage 21a corresponding to each cylinder 12A to 12D, and the upstream end of each branch intake passage 21a. Are respectively communicated with the surge tank 21b. A common intake passage 21c is provided upstream of the surge tank 21b. A throttle body 24 is provided in the common intake passage 21c. The throttle body 24 includes a throttle valve 24a capable of adjusting the amount of air flowing into each of the cylinders 12A to 12D, an actuator 24b that drives the throttle valve 24a, an idling speed control device (ISC) 24c, Is provided. In the illustrated embodiment, the ISC 24c is of an electromagnetic drive type in which the valve opening amount can be changed by the combustion control unit 101 (see FIG. 3) of the engine control unit 100. An air flow sensor 25 for detecting the intake flow rate and an intake pressure sensor 26 for detecting the intake pressure are provided on the upstream side and the downstream side of the throttle valve 24a, respectively.

  Further, as shown in FIG. 1, the engine 1 is provided with an alternator 28 connected to the crankshaft 3 by a timing belt or the like. The alternator 28 includes a regulator circuit 28a that adjusts the amount of power generation by controlling the output voltage by controlling the current of a field coil (not shown). The engine control unit 100 (FIG. 3) is input to the regulator circuit 28a. Based on the control signal from the reference), the power generation amount corresponding to the vehicle electrical load of the vehicle and the voltage of the battery mounted on the vehicle is executed.

  Further, the engine 1 is provided with a starter 36 as an electric drive device. The starter 36 includes a motor 36a (electric motor) and a pinion gear 36d, and drives the engine 1. The rotation shaft of the pinion gear 36d is coaxial with the output shaft of the motor 36a, and reciprocates along the rotation shaft. The crankshaft 3 is provided with a flywheel (not shown) and a ring gear 35 fixed to the flywheel concentrically with the center of rotation. When the starter 36 is used to start the engine, the pinion gear 36d moves to a predetermined meshing position and meshes with the ring gear 35, so that the crankshaft 3 is rotationally driven. Yes (cranking).

  There are two modes for starting the engine by the starter 36. In the first mode, the driver turns an ignition key switch (not shown) to drive the starter 36, thereby starting the engine 1, which is called key start. In the second mode, the starter control unit 103 (see FIG. 3) of the engine control unit 100 automatically drives the starter 36 at the time of restart after the engine is automatically stopped, thereby starting the engine 1. .

  The engine 1 is also provided with two crank angle sensors 30 and 31 that detect the rotation angle of the crankshaft 3. The engine rotation speed Ne is detected based on a detection signal (pulse signal) output from one crank angle sensor 30, and based on detection signals out of phase output from both the crank angle sensors 30, 31. The rotation angle of the crankshaft 3 is detected. Further, the engine 1 includes a cam angle sensor 32 that detects the rotational position of the intake camshaft, a water temperature sensor 33 that detects the coolant temperature, and an accelerator that detects the accelerator opening corresponding to the accelerator operation amount of the driver. An opening sensor 34 is provided.

  FIG. 3 is a control block diagram centering on the engine control unit 100 of the vehicle according to the present invention. In FIG. 3, only the portions necessary for the description of the present embodiment are extracted and shown.

  The engine control unit 100 includes various sensors and switches described above, that is, an air flow sensor 25, an intake pressure sensor 26, a crank angle sensor 30, 31, a cam angle sensor 32, a water temperature sensor 33, an accelerator opening sensor 34, and the like. A signal from the input element is input.

  The engine control unit 100 also outputs a control signal to output elements such as the fuel injection valve 16, the throttle valve 24a, the ignition device 27, the alternator 28, the starter 36, and the like.

  The engine control unit 100 is composed of a microprocessor having a CPU, a memory, a counter timer group, an interface, and a bus connecting them. The engine control unit 100 logically configures a combustion control unit 101, a piston position determination unit 102, and a starter control unit 103.

  Combustion control unit 101 performs appropriate throttle opening of engine 1 based on sensor signals from air flow sensor 25, intake pressure sensor 26, crank angle sensors 30, 31, cam angle sensor 32, water temperature sensor 33, and accelerator opening sensor 34. The degree (intake amount), the fuel injection amount and its injection timing, and the appropriate ignition timing are set, and the control signal is output to the fuel injection valve 16, the throttle valve 24a (the actuator 24b thereof), and the ignition device 27.

  In the present embodiment, the engine 1 is automatically stopped when a predetermined automatic stop condition is satisfied, and is automatically restarted when a predetermined restart condition is satisfied after the stop. ing. In the restart control according to the present embodiment, the starter combined restart control using the starter 36 is executed when the restart condition is satisfied.

  The piston position determination unit 102 calculates the position of the piston 13 based on signals from the crank angle sensors 30 and 31. The piston position determination unit 102 also determines a stop position of the piston 13 when the engine 1 is automatically stopped.

  The starter controller 103 sends a drive signal to the starter 36 to drive the starter 36 when the starter 36 needs to be driven at the time of key start and restart in the engine automatic stop control.

  Next, a control map stored in the memory of the engine control unit 100 will be described.

  FIG. 4 is a graph showing the fuel injection amount, the fuel injection stage, and the relationship between the ignition timing and the crank angle according to the present embodiment.

  Referring to FIG. 4, in the present embodiment, based on the graph shown in FIG. 4, the fuel injection amount, the fuel injection stage, and the ignition timing are mapped and stored in the memory based on the piston stop position. .

  The piston stop position of the intake stroke cylinder at the time of stop according to the present embodiment is a first stop range that is within a predetermined range from the bottom dead center and a second range that is within a predetermined range from the top dead center side with respect to the first stop range. It is divided into a stop range and a third stop range from the top dead center side to the top dead center with respect to the second stop range. And when the piston 13 has stopped in the 1st stop range, it sets so that the fuel cut control which cuts fuel injection may be performed. This is because the amount of air is large in the first stop range, and the method of enriching the air-fuel ratio by fuel injection cannot prevent the pre-ignition sufficiently, so the pre-ignition is surely prevented by stopping the fuel supply. I am trying to do it.

  Next, when the piston 13 is stopped in the second stop range, the fuel injection amount is relatively rich (for example, approximately 13 in A / F) except for the boundary portion with the third stop range. It is set so as to execute a split injection that divides the fuel injection stage into two times. This is because in the intake stroke cylinder when the piston 13 is stopped in the second stop range, a cooling effect due to vaporization latent heat is exerted, and in order to prevent pre-ignition, the fuel injection stage is set to two stages, so that A weakly stratified air-fuel mixture is formed to suppress the generation of smoke. Further, when the piston 13 stops in the second stop range, the ignition timing is also retarded. Normally, in an idling stop type engine, when performing the combustion of the air-fuel mixture in the intake stroke cylinder at the time of stop, the ignition timing is retarded after the compression top dead center elapses from the viewpoint of preventing the occurrence of reverse torque. However, by further retarding the ignition timing, pre-ignition can be prevented more reliably.

  Further, in the third range, the fuel injection amount is reduced, and the fuel injection stage is also changed to one stage. When the piston 13 stops in the third range, the amount of air in the cylinder is small in the stop intake stroke cylinder 12C, so even if the heat receiving period in the stop intake stroke cylinder 12C becomes long, fresh air is generated. The pre-ignition is less likely to occur due to the cooling effect. Therefore, when the piston 13 of the intake stroke cylinder 12C at the time of stoppage is stopped in the third range, the air-fuel ratio is set to the lean side (for example, approximately 12 to approximately 16 in A / F) to suppress the generation of smoke. I try to prevent it.

  In the present embodiment, the boundary portion between the second range and the third range is set so that the fuel injection amount decreases toward the top dead center. Further, with respect to the ignition timing, the ignition timing is retarded at the boundary between the second range and the third range from the viewpoint of prevention of blow-up.

  Next, automatic stop / restart control based on this embodiment will be described.

  5 and 6 are flowcharts centering on control by the engine control unit 100, particularly automatic stop control. FIG. 5 shows the control until the engine 1 stops, and FIG. 6 shows the subsequent restart control.

  First, referring to FIG. 5, engine control unit 100 waits until a preset engine automatic stop condition is satisfied (step S <b> 10). Specifically, when the brake operation state continues for a predetermined time and the vehicle speed is equal to or lower than a predetermined value, it is determined that the engine automatic stop condition is satisfied.

  If it is determined in step S10 that the automatic stop condition is satisfied, engine speed adjustment control including alternator control is started (step S12). Specifically, the engine rotation speed Ne is adjusted to the rotation speed N1 before stopping (for example, 760 rpm). Then, after the engine rotation speed Ne becomes N1 (YES in step S13), the fuel supply from the fuel injection valve 16 is stopped (step S14).

  Subsequently, the engine control unit 100 opens the throttle valve 24a (step S15), and waits for the engine rotational speed Ne to become lower than a predetermined rotational speed N2 (for example, about 500 rpm) (step S16). If YES in step S16, the engine control unit 100 closes the throttle valve 24a (step S17). After that, the engine control unit 100 continues the alternator control and continues the adjustment of the stop position of the piston 13, and waits for the engine 1 to completely stop based on the detection values of the crank angle sensors 30, 31 (step S18). ). The engine control unit 100 continues to control the adjustment of the stop position of the piston 13 until the engine 1 is completely stopped. When the engine 1 is completely stopped, the alternator control is terminated (step S19), and the crank angle is determined. The stop position of the piston 13 determined by the piston position determination unit 102 based on the detection of the sensors 30 and 31 is stored (step S20).

  Next, engine restart will be described with reference to FIG. The engine control unit 100 waits for the restart condition to be satisfied after the engine 1 is stopped (step S21). Examples of the restart condition include an accelerator operation by the driver. When this restart condition is satisfied, the engine control unit 100 determines whether or not it is in the combustion restart operation region, that is, whether or not the assist condition by the starter 36 is satisfied (step S22). Specifically, based on the determination result of the piston position determination unit 102, the piston stop position of the stop-time compression stroke cylinder 12A is within a predetermined piston stop range (for example, 80 ° before compression top dead center to 40 ° before compression top dead center). ), It is determined as the combustion restart operation region, and otherwise, it is determined as the starter combined operation region (assist condition is satisfied). If in the combustion restart operation region, the combustion restart subroutine is executed (step S23), the normal operation control subroutine (step S24) is further executed, and the process is terminated. As the combustion restart subroutine, for example, the one disclosed in Japanese Patent Laid-Open No. 2005-2847 previously proposed by the applicant of the present application can be applied as it is, and therefore the details thereof are omitted. .

  On the other hand, in step S22, when it is determined as the starter combined operation region (determined that the assist condition is satisfied), the engine control unit 100 reads the data from the map based on the graph of FIG. The fuel injection amount (air-fuel ratio), fuel injection stage, and ignition timing of the hour intake stroke cylinder 12C are calculated (step S25). By this calculation, the combustion control in the stop-time intake stroke cylinder 12C is executed based on the state of the piston stop position.

  Next, the engine control unit 100 drives the starter 36 (step S26), and executes fuel injection control of the stop-time expansion stroke cylinder 12B (step S27). Thereafter, the engine control unit 100 performs ignition control in the stop-time expansion stroke cylinder 12B (step S28). Next, the engine control unit 100 injects fuel into the stop-time compression stroke cylinder 12A (step S29). By this fuel injection control, the temperature and pressure are reduced by the latent heat of vaporization in the stop-time compression stroke cylinder 12A, so that the compression reaction force in the stop-time compression stroke cylinder 12A is reduced and the restart of the engine 1 is made smooth. Can do.

  Next, the engine control unit 100 waits for the piston 13 of the compression stroke cylinder 12A at the time of stop to pass the compression top dead center (step S30), and when it has elapsed, the spark plug 15 of the compression stroke cylinder 12A at the time of stop. Is operated to burn the air-fuel mixture. As a result, torque is output even in the stop-time compression stroke cylinder 12A, and restart of the engine 1 is energized.

  Next, the engine control unit 100 executes injection control in the stop-time intake stroke cylinder 12C based on the calculation result of step S25 (step S32).

  As shown in FIG. 4, when the piston stop position in the stop-time intake stroke cylinder 12C is in the first range, the fuel injection is cut, and therefore ignition is not performed. By this fuel cut, pre-ignition can be reliably prevented even in a stopped state where the volume in the cylinder is large and the heat receiving period is long.

  Further, when the piston stop position in the stop-time intake stroke cylinder 12C is in the second range, relatively rich fuel (for example, about 13 in A / F) is divided and injected in two stages.

  Further, when the piston stop position in the stop-time intake stroke cylinder 12C is in the third range, the fuel injection amount is returned to the lean side, and the fuel injection stage is also set to one stage.

  After the fuel injection control in step S32 is completed, the engine control unit 100 waits for the piston 13 of the stop-time intake stroke cylinder 12C to pass the compression top dead center (step S33). When the piston 13 of the stop-time intake stroke cylinder 12C has passed the compression top dead center, the engine control unit 100 executes ignition control of the stop-time intake stroke cylinder 12C (step S34). In this ignition control, when the piston stop position in the intake stroke cylinder 12C at the time of stop is within the first range, ignition is not performed and the process proceeds to the next step as it is.

  Further, when the piston stop position in the intake stroke cylinder 12C at the time of stop is in the second range, the ignition timing is further retarded than the ignition timing after the compression top dead center has been set to prevent the blow-up.

  Furthermore, when the piston stop position in the intake stroke cylinder 12C at the time of stop is in the third range, the ignition timing is retarded to the ignition timing after the elapse of the compression top dead center that is set to prevent the blow-up.

  Next, the engine control unit 100 performs blow-up control (step S35). This blow-up control is performed in the intake passage 21 in each of the stop exhaust stroke cylinder 12D that shifts to the intake stroke next to the stop intake stroke cylinder 12C and each of the cylinders 12B, 12A, and 12C that sequentially reach the intake stroke. In consideration of the fact that air in a state close to atmospheric pressure is inhaled to a relatively high air filling state, while the intake pipe negative pressure is relatively small (while the intake pressure is high), each of the cylinders 12A to 12D This is a control that suppresses an excessive increase in torque by retarding the ignition timing.

  When the intake pipe negative pressure becomes relatively large, the engine control unit 100 proceeds to step S23 and ends the process.

  As described above, in this embodiment, suitable fuel supply is executed according to the piston stop position. That is, in the first stop range, since the amount of air in the cylinder that is received when the engine 1 is automatically stopped is large, the method of enriching the air-fuel ratio by fuel injection cannot sufficiently prevent preignition. By stopping, the pre-ignition is surely prevented. Further, in the second stop range, fuel is dividedly injected into the stop-time intake stroke cylinder 12C, so that the cooling effect due to vaporization latent heat and the occurrence of pre-ignition can be suppressed while preventing smoke. Combustion time can be shortened, and high output and fuel efficiency can be improved. Further, since the air-fuel ratio is corrected to the lean side in the third stop range, it is possible to suppress the occurrence of smoke due to an unnecessary increase in fuel.

  Further, in the present embodiment, the combustion control unit 101 sets the ignition timing to be higher than the ignition timing in the third stop range when the piston stop position of the stop-time intake stroke cylinder 12C is in the second stop range. It is to be retarded. For this reason, in this embodiment, the pre-ignition in the stop-time intake stroke cylinder 12C can be more effectively suppressed. That is, when the intake stroke cylinder 12C at the time of stop is stopped in the second stop range, the amount of air in the cylinder received during the automatic stop of the engine is larger than when stopped at the third stop range. Many. Therefore, by retarding the ignition timing in the second stop range from the ignition timing in the third stop range, self-ignition is prevented while ensuring startability according to the piston stop position. Can do.

  Furthermore, in the present embodiment, the starter 36 that can assist the start of the stopped engine 1 and the starter 36 that is driven when a predetermined assist condition based on the determination of the piston position determination unit 102 is satisfied when the restart condition is satisfied. The starter control unit 103 drives the starter 36 at least when the piston stop position of the stop-time intake stroke cylinder 12C is within the first stop range. For this reason, in the present embodiment, the driving force of the engine 1 can be secured by the starter 36 when the stop-time intake stroke cylinder 12C is stopped in the first range.

  The above-described embodiments are merely preferred specific examples of the present invention, and the present invention is not limited to the above-described embodiments. It goes without saying that various modifications are possible within the scope of the claims of the present invention.

1 is a schematic cross-sectional view showing a schematic configuration of a vehicle engine according to the present invention. 1 is a schematic plan view showing a schematic configuration of a vehicle engine according to the present invention. It is a control block diagram centering on the control unit of the vehicle which concerns on this invention. It is a graph which shows the relationship between the fuel injection quantity which concerns on this embodiment, a fuel injection stage, and ignition timing, and a crank angle. It is a flowchart centering on control by a control unit, especially automatic stop control. It is a flowchart centering on control by a control unit, especially restart control.

DESCRIPTION OF SYMBOLS 1 Vehicle engine 12A Stop compression stroke cylinder 12B Stop expansion stroke cylinder 12C Stop intake stroke cylinder 12D Stop exhaust stroke cylinder 13 Piston 15 Spark plug 16 Fuel injection valve 27 Ignition device 28 Alternator 30, 31 Crank angle sensor 36 Starter DESCRIPTION OF SYMBOLS 100 Engine control unit 101 Combustion control part 102 Piston position determination part 103 Starter control part (an example of an electric drive device control part)

Claims (3)

In the vehicle engine control device for automatically stopping the engine when a predetermined automatic stop condition is satisfied, and restarting the engine after the automatic stop when the predetermined restart condition is satisfied,
A piston position determination unit for determining a piston stop position when the engine is automatically stopped;
A combustion control unit that controls the combustion of the engine based on the determination of the piston position determination unit,
The combustion control unit performs fuel injection and ignition on at least one of a stop expansion stroke cylinder in an expansion stroke at the time of automatic stop and a stop compression stroke cylinder in a compression stroke at the time of automatic stop, and at the time of automatic stop The injection control is performed on the intake stroke cylinder at the time of stop in the intake stroke,
The injection control for the stop-time intake stroke cylinder includes stopping fuel supply to the stop-time intake stroke cylinder in a first stop range where the piston stop position of the stop-time intake stroke cylinder is within a predetermined range from bottom dead center, In the second stop range that is within a predetermined range from the top dead center side with respect to the first stop range, at least a part of the fuel set at a constant amount regardless of the piston stop position is divided into a plurality of times. Injecting and in a third stop range from the top dead center side to the top dead center with respect to the second stop range, a smaller amount of fuel is injected than a fixed amount of fuel set in the second stop range. Monodea is,
When the piston stop position of the intake stroke cylinder at the time of stop is at least in the second and third stop ranges, the ignition timing is retarded by the combustion control unit until after the elapse of compression top dead center, and the piston stop position is The vehicle engine control device is characterized in that the retard amount of the ignition timing when in the second stop range is set to be larger than the retard amount when in the third stop range . The vehicle engine control device according to claim 1,
When the piston stop position of the stop-time intake stroke cylinder is at the boundary between the second stop range and the third stop range, the combustion control unit increases the fuel injection amount toward the top dead center side. A control device for a vehicle engine characterized by being reduced. The control device for a vehicle engine according to claim 1 or 2 ,
An electric drive device capable of assisting in starting the stopped engine;
An electric drive device control unit that drives the electric drive device when a predetermined assist condition based on the determination of the piston position determination unit is satisfied when the restart condition is satisfied, and
The electric drive control unit is configured to drive the electric drive when at least a piston stop position of the intake stroke cylinder at the time of stop is in the first stop range. apparatus.

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