JP4826543B2 - 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.

  For example, as disclosed in Patent Documents 1 and 2, in this type of vehicle engine control device, when a predetermined engine stop condition is satisfied, the engine is automatically stopped, and after the engine is automatically stopped, It is known that when the restart condition is satisfied, the air-fuel mixture is combusted at least in the expansion stroke cylinder at the time of stop when the engine is stopped and the engine is restarted.

  In order to restart the engine by combustion, it is necessary to ensure sufficient combustion energy obtained in the stop expansion stroke cylinder that was in the expansion stroke at the time of stop. The cylinder must overcome the compression reaction force and exceed the compression top dead center. For this purpose, it is necessary to ensure a sufficient amount of air in the cylinder during the expansion stroke during the stop. Further, in order to obtain the engine reverse rotation energy necessary for compressing the air, it is necessary to secure an air amount of a certain amount or more in the compression stroke cylinder at the time of stop.

  In order to satisfy this requirement, Patent Document 1 discloses a technique for braking and scavenging the engine by controlling the opening of the throttle valve and the alternator when the engine is automatically stopped.

  The stop position of the piston is determined by the balance of the air amount in each cylinder. For this reason, the relationship between the engine rotation speed and the piston stop position may change in accordance with individual differences between engines, changes in engine temperature, and atmospheric conditions. In such a case, the piston cannot be stopped at a desired position even if the engine rotational speed is adjusted by controlling the alternator based on the relationship between the preset engine rotational speed and the piston stop position. Not a few.

Therefore, in the technique disclosed in Patent Document 2, when the restart condition is satisfied after the engine is stopped, the engine stop state is determined. If the determination result is negative, an electric drive such as a starter is performed. A technique for restarting an engine with an apparatus is disclosed.
JP 2004-293474 A JP 2004-245219 A

  In the technologies disclosed in each of Patent Documents 1 and 2 described above, control for stopping the piston at an intended position is executed when the automatic stop condition is satisfied regardless of the driving state of the vehicle. become. However, in the piston stop position control as described above, since the engine braking period becomes considerably long, the piston stop position control is uniformly performed in spite of the operating condition in which restart is expected by the electric drive device. It is not preferable in terms of time and cost.

  This invention is made | formed in view of the said malfunction, and makes it the subject to provide the control apparatus of the vehicle engine which can suppress useless piston stop position control.

In order to solve the above problems, the present invention automatically stops the engine when a predetermined engine stop condition is satisfied, and at least when the engine is stopped when the predetermined restart condition is satisfied after the engine is automatically stopped. In the control apparatus for a vehicle engine that restarts the engine by combusting the air-fuel mixture in the expansion stroke cylinder at the time of stop, the operation state determination unit that determines the operation state of the engine and the determination of the operation state determination unit And a combustion control unit that controls at least the throttle opening, the fuel injection amount, and the injection timing of the engine, and that controls the automatic stop and restart control of the engine. When the predetermined assist condition based on the determination of the drive device and the driving state determination unit is satisfied when the restart condition is satisfied, the power And an electric drive control unit for driving the driving device, the combustion control unit is configured in a case where the engine stop condition is satisfied, the combustion only restarted by the engine is in expected operating condition and the operating condition determining When the engine determines that the engine stop condition is satisfied, a rotational speed control process for increasing the idling rotational speed of the engine to a predetermined speed is executed, and the throttle opening of the engine after the fuel cut is set to a predetermined first value. When the operation state determination unit determines that the operation state is expected to be used together with the electric drive device at the time of restarting, a simple stop process that omits the rotation speed control process is performed. with automatically stopping the engine, set the throttle opening to a lower second braking time opening than said first braking opening A control device for a vehicle engine, characterized in that it is intended to.

In this aspect, when the engine is automatically stopped, useless piston stop position control can be suppressed in accordance with the driving situation. That is, in order to precisely control the piston stop position, it is preferable to once execute a rotational speed control process for increasing the rotational speed when the engine is idling, and reduce the engine rotational speed in the subsequent braking control. However, if it is expected that the electric drive unit will be used at the time of restarting, even if such a rotational speed control process is executed , the braking time will be increased, and the efficiency of restarting will be increased. It will not contribute . On the other hand, in this mode, when it is determined that the operation state is expected to be used together with the electric drive device at the time of restart, the engine is automatically stopped by the simple stop process in which the rotation speed control process is omitted. Therefore, the braking control can be simplified and the braking time can be shortened.

Further, in the above-described aspect, in an operation state in which the combustion of the engine is expected to be restarted, the throttle opening of the engine after the fuel cut is increased to the predetermined first braking opening, and sufficient scavenging is performed and the engine is stopped. The compression reaction force in the time expansion stroke cylinder and the compression reaction force in the stop time compression stroke cylinder are adjusted and controlled, and the piston stop position can be stopped within a desired appropriate range, and the electric drive device can be restarted In an operation state in which the combined use is expected, the throttle opening is kept at the second braking opening that is smaller than the first braking opening, so that the necessary scavenging is achieved and the vibration accompanying the increase in the throttle opening. And deterioration of fuel consumption can be suppressed.

In a preferred aspect, a generator control unit for controlling the generator of the engine is provided, and the generator control unit temporarily sets the engine generator to a maximum load after fuel cut when the engine stop condition is satisfied. And then reducing the load of the generator to a predetermined value, and the period during which the generator is operated at the maximum load is in an operating state in which the engine can be restarted only by combustion. And when the operation state determination unit determines that the operation state determination unit determines that it is in an operation state in which the combined use of the electric drive device is expected at the time of restart, The second period is set shorter than the first period. In this aspect, when the engine is braked with the generator, the engine can be stopped in a necessary and sufficient braking period. That is, in the operation region where combustion restart is expected, the generator operating time can be set to be relatively long, the engine speed can be sufficiently reduced, the engine can be stopped within the intended stop range, and the engine can be restarted. In an operating state in which the electric drive device is expected to be used at the time of start-up, the generator operating time can be set to a minimum required period to prevent lamp flickering due to voltage fluctuations as much as possible. .

As described above, in the present invention, when it is determined at the time of restart that the electric drive device is expected to be used in combination, the engine is automatically operated by the simple stop process in which the predetermined rotational speed control process is omitted. Since the vehicle is stopped, the braking control can be simplified and the braking time can be shortened.

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

  1 and 2 are configuration diagrams showing a schematic configuration of a vehicle engine 1 according to the present embodiment of 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 102 (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 102 (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 as a generator 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.

  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.

  An atmospheric pressure sensor 39 is connected to the engine control unit 100 as air density state detection means for detecting the air density state in each of the cylinders 24 </ b> A to 24 </ b> D of the engine 1. The engine control unit 100 determines that the air density in each of the cylinders 12A to 12D is higher as the detection signal from the atmospheric pressure sensor 39 is higher.

  FIG. 3 is a control block diagram centering on the engine control unit 100 of the vehicle according to this embodiment of 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 the above-described various sensors and switches, that is, the air flow sensor 25, the intake pressure sensor 26, the crank angle sensors 30, 31, the cam angle sensor 32, the water temperature sensor 33, the accelerator opening sensor 34, and the large sensor. A signal from an input element such as the atmospheric pressure sensor 39 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 102, an operating state determination unit 101, a starter control unit 103, and an alternator control unit 104.

  The driving state determination unit 101 determines the position of the piston 13 based on the sensor signals from the air flow sensor 25, the intake pressure sensor 26, the crank angle sensors 30, 31, the cam angle sensor 32, the water temperature sensor 33, and the accelerator opening sensor 34, Various operating states, such as in-cylinder temperature or whether the engine 1 is rotating forward, are determined.

  The operation state determination unit 101 also determines a stop position of the piston 13 when the engine 1 is automatically stopped. Further, the operation state determined by the operation state determination unit 101 includes the in-cylinder temperature of each cylinder estimated based on data stored in advance in memory, the success or failure of an assist condition, or a condition that combustion cannot be restarted. .

  The assist condition refers to a condition that requires assistance from the starter 36 when, for example, the stop position of the piston 13 deviates from a predetermined stop position stored in advance in the memory.

  The condition that combustion cannot be restarted refers to an operating state in which the engine 1 cannot be restarted by combustion after the engine 1 is automatically stopped, and the starter 36 needs to be assisted. In the present embodiment, the condition that the combustion restart is impossible is when the water temperature of the engine 1 detected by the water temperature sensor 33 is higher than 80 ° C. and lower than 110 ° C., or when the atmospheric pressure is higher than the standard atmospheric pressure (= 1013 hPa). This is a case of a value equivalent to a low altitude and a mountainous area (for example, 89.459 hPa). In these operating states, it is determined that it is difficult to control the stop position of the piston 13 or the operating environment is likely to cause autoignition in the intake stroke cylinder 12C at the time of stop. This is because the engine 1 is not restarted but is controlled so as to restart the engine 1 by using the starter 36 together. In the present embodiment, the memory of the engine control unit 100 is provided with a storage area for storing a flag, and the operation state determined by the operation state determination unit 101 satisfies the combustion restart disabled condition. At this time, the value of the flag F is set to 1; otherwise, the value of the flag F is set to 0. The initial value of the flag F is set to 0.

  The combustion control unit 102 sets an appropriate throttle opening (intake amount), a fuel injection amount and its injection timing, and an appropriate ignition timing of the engine 1 based on the determination of the operation state determination unit 101, and uses the control signal as the fuel. This is output to the injection valve 16, the throttle valve 24a (the actuator 24b thereof), and the ignition device 27. In the present embodiment, the control of the combustion control unit 102 automatically stops the engine 1 when a predetermined automatic stop condition is satisfied, and automatically stops the engine 1 when a predetermined restart condition is satisfied after the stop. Is configured to restart automatically. In the present embodiment, when the restart condition is satisfied, combustion restart control that automatically restarts the engine by combustion in the stop expansion stroke cylinder 12B that was in the expansion stroke when the engine 1 was automatically stopped; One of the control methods of the starter combined restart control using the starter 36 is selected and executed.

  The starter control unit 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.

  The alternator control unit 104 controls the duty ratio of the alternator 28.

  Next, an example of engine control according to the present embodiment will be described.

  4 and 5 are flowcharts showing an example of the automatic engine stop control according to the present embodiment. FIG. 6 is a timing chart showing the engine speed when FIG. 4 and FIG. 5 are executed. In FIG. 6, the solid line indicates a control example when the combustion restart disabled condition is satisfied, and the broken line indicates a control example when the combustion restart disabled condition is not satisfied.

  Referring to FIG. 4, engine control unit 100 initializes the value of flag F related to the condition that combustion restart is not possible (F = 0) in the automatic stop control of engine 1 (step S20). Next, the system waits for the engine stop condition to be satisfied (step S21). When the engine stop condition is satisfied, it is further determined whether or not the condition for preventing combustion restart is satisfied from the sensor signals of the water temperature sensor 33 and the atmospheric pressure sensor 39 (step S21). S22). If the combustion restart impossible condition is satisfied, the engine control unit 100 updates the value of the flag F to 1 (step S23), and sets the throttle opening Th to a predetermined braking opening Th2 (for example, Th2). = 20%, second braking opening degree) (step S24), and the driving period Ta of the alternator 28 is set to a predetermined driving period Ta2 (second driving period) (step S25).

  On the other hand, when it is determined in step S22 that the condition for preventing combustion restart is not satisfied, the engine control unit 100 executes control for increasing the idling rotational speed (step S26). By this control, the engine 1 once rotates at a rotational speed Ne (for example, 810 rpm) higher than the rotational speed (for example, 600 rpm) during normal idling operation, and it becomes possible to improve the accuracy of the subsequent braking control. . Further, the engine control unit 100 sets the throttle opening degree Th to a predetermined braking opening degree Th1 (for example, Th1 = 30%, first braking opening degree)% (step S27), and the alternator 28 drive period. Ta is set to a predetermined driving period Ta1 (first driving period) (step S28).

In each setting of steps S24, S25, S27, and S28, the relationship between the setting values is
Th1> Th2,
Ta1> Ta2
It has become.

  Next, referring to FIG. 5 and FIG. 6, when the processing up to step S25 or step S28 is completed, engine control unit 100 executes fuel cut at timing t1 and controls the throttle opening to Th. (Step S31). As a result, the engine 1 decelerates from the timing t1, but when the operating state satisfies the condition that the combustion restart is not possible, the simple stop in which the increase control of the idle rotation speed shown in step S26 is omitted. Since the engine 1 is braked by the processing, the period from the timing t0 when the engine stop condition is satisfied to the timing t1 can be shortened as much as possible. On the other hand, if the condition for preventing the combustion restart is not satisfied, the engine control unit 100 executes the fuel cut control and the like after performing the idle speed increase control shown in step S26. Although it can be executed, the period from timing t0 to timing t1 is relatively long. On the other hand, the throttle opening degree Th set in step S31 differs depending on whether or not the condition for preventing combustion restart is satisfied (steps S24 and S27). For this reason, in the present embodiment, when the condition that combustion restart is not possible is not established, the throttle opening Th is set to the relatively high first braking opening Th1, so that the boost pressure is increased, While sufficient scavenging can be achieved, the throttle opening degree Th is set to the second braking opening degree Th2 lower than the first braking opening degree Th1 when the combustion restart impossible condition is satisfied. Therefore, vibration of the engine 1, particularly resonance at the mount portion with the vehicle can be prevented, and noise and the like can be suppressed.

  The engine 1 is decelerated by the fuel cut. The engine control unit 100 waits for the engine 1 to decelerate below the predetermined rotational speed N1 (step S32). When the engine 1 decelerates to the rotational speed N1 or less, at the timing t2, the engine control unit 100 increases the alternator drive duty ratio to 100% (step S33). Due to the increase in the duty ratio, the rotational speed Ne of the engine 1 is further reduced. Next, the throttle opening degree Th is reduced to Th3 lower than the set value described above. In this embodiment, the throttle opening degree Th is not controlled based on the rotational speed Ne of the engine 1, but the alternator 28 is driven. It is determined by the drive period Ta from the timing t2 when the duty ratio is changed to 100%. The drive period Ta is set to a relatively long first drive period Ta1 when the combustion restart impossibility condition is not established, while the drive period Ta is set to the first when the combustion restart impossibility condition is established. Is set to Ta2 shorter than the driving period Ta1 (steps S25 and S28). As a result, when the condition that combustion cannot be restarted is not satisfied, the engine 1 can be reliably braked by the alternator 28. On the other hand, when the condition that combustion cannot be restarted is satisfied, the lamp accompanying an increase in the load on the alternator 28 Flickering can be prevented.

  After the driving period Ta, the throttle opening degree Th is set to C% (for example, C = 10%) lower than the second braking opening degree Th2 (steps S35 and S36). By this control, the boost pressure Bt starts to decrease slightly after the timing t3, and the intake flow rate sucked into each cylinder 12A to 12D of the engine 1 decreases. Air sucked between timing t1 and timing t2 when the throttle valve 24a is opened is guided to the branch intake passage 21a of each cylinder 12A to 12D via the common intake passage 21c and the surge tank 21b. Then, the air is sucked in order from the cylinders 12A to 12D that have reached the intake stroke.

  When the engine speed Ne further decreases and the final compression top dead center passage timing (timing t4 shown in FIG. 6) is passed, none of the cylinders 12A to 12D passes the top dead center, and the transition of the stroke is It will not be done. The piston 13 is damped and oscillated within its stroke (when the piston 13 moves in the opposite direction, the crankshaft 3 is reversed and the engine rotational speed Ne becomes negative).

  Therefore, the engine control unit 100 waits for the rotational speed Ne of the engine 1 to fall below the predetermined reference speed N2 (step S37).

  When the rotational speed Ne is reduced below the reference speed N2, the opening degree Th of the throttle valve 24a is increased to, for example, about 40% almost simultaneously with the timing t4 (may be slightly delayed). The drive duty ratio is controlled according to the engine rotational speed Ne (step S38), and the control of the drive duty ratio of the alternator 28 is repeated until the engine 1 is stopped (step S39). This makes it easier for the piston 13 to stop at a target position according to the balance without affecting the intake flow rate balance in the stop-time compression stroke cylinder 12A or the stop-time compression stroke cylinder 12A.

  It should be noted that the control after step S37 may be omitted when the flag F is 1, that is, when the condition for preventing combustion restart is satisfied.

  Referring to FIG. 6, in the control procedure described above, when the condition for preventing combustion restart is satisfied, the engine 1 can be braked by the simple stop process in which the idle rotation speed control (step S26) and the like are omitted. As a result, the braking time can be shortened, and the reduction in fuel consumption can be suppressed.

  FIG. 7 is a flowchart showing a control example at the time of engine restart according to the present embodiment.

  Referring to FIG. 7, engine control unit 100 waits for a restart condition to be satisfied after engine 1 is stopped (step S40). The restart condition is determined by, for example, detecting the accelerator operation by the driver with the accelerator opening sensor 34.

  When the restart condition is satisfied, the engine control unit 100 refers to the value of the flag F and determines whether or not the value of the flag F is 0 (step S41). If the value of the flag F is 1, that is, if the combustion restart impossible condition is satisfied, the engine control unit 100 immediately executes the starter combined restart subroutine (step S42). On the other hand, when the value of the flag F is 0, that is, when the condition for preventing combustion restart is not satisfied, the engine control unit 100 further determines whether or not the piston 13 is stopped at a predetermined stop position. However, if not stopped at the predetermined stop position, the starter combined use restart subroutine (step S42) is executed, while if stopped, the combustion restart subroutine is executed (step S42). S44). When the value of the flag F is 1, or when the piston 13 is not stopped at the predetermined stop position, it is difficult to drive the engine 1 only by combustion even if the combustion restart control is executed. Therefore, determinations such as steps S41 and S43 are made before reaching the combustion restart subroutine, and the combustion restart subroutine is executed only when the engine 1 is stopped in a state suitable for combustion restart. -ing

  Since the combustion restart subroutine and the starter combined restart subroutine itself can be implemented by a known technique, description thereof will be omitted.

  After executing any of these subroutines, the engine control unit 100 executes a known normal operation subroutine (step S45) and ends the process.

As described above, in the present embodiment, when the engine 1 is automatically stopped, useless piston stop position control can be suppressed in accordance with the driving situation. That is, in an operation state in which the starter 36 is expected to be used at the time of restart, even if the piston stop position is controlled, the braking time is simply increased, and it does not contribute to the efficiency of the restart. In this embodiment, when it is determined that the engine is in an operation state in which the starter 36 is expected to be used at the time of restart, that is, when the condition for preventing combustion restart is satisfied , the engine 1 is stopped after the engine stop condition is satisfied. Since the engine 1 is automatically stopped by the simple stop process in which the rotational speed control process for raising the idling rotational speed to a predetermined speed is omitted, the braking control can be simplified and the braking time can be shortened.

Ie, in order to precisely control the piston stop position is once performs a rotation speed control process to increase the rotational speed at which the engine 1 is in the idling, in the subsequent brake control, the engine Rotation speed but is the preferred reducing, when the combination of the starter 36 is expected at the time of restart, there is no need to precisely control the piston stop position, the rotational speed control process which is performed early in the engine stop control Thus, the braking time can be shortened.

  Further, in the present embodiment, the combustion control unit 102 increases the throttle opening Th of the engine 1 after the fuel cut when the engine stop condition is satisfied, and the throttle opening Th is changed to an engine based only on combustion. When the operation state determination unit 101 determines that the vehicle is in an operation state in which a restart of 1 is expected, the predetermined first braking opening degree Th1 is set, while the operation state in which the starter 36 is expected to be used at the time of restart is set. When the driving state determination unit 101 determines that there is, the second braking opening degree Th2 is set lower than the first braking opening degree Th1. Therefore, in the present embodiment, in an operation state in which combustion restart of the engine 1 is expected, the throttle opening degree Th of the engine 1 after the fuel cut is increased to a predetermined first braking opening degree Th1, and sufficient scavenging is performed. In addition, the compression reaction force in the stop expansion stroke cylinder 12B and the compression reaction force in the stop compression stroke cylinder 12A can be adjusted and controlled, and the piston stop position can be stopped within a desired appropriate range. In an operation state in which the starter 36 is expected to be used at the time of start-up, the throttle opening Th is kept at the second braking opening Th2, which is smaller than the first braking opening Th1, so that the necessary scavenging is achieved and the throttle It is possible to suppress the vibration and the deterioration of fuel consumption accompanying the increase in the opening degree Th.

In this embodiment, the alternator control unit 104 (generator control unit) once sets the alternator 28 as the generator of the engine 1 to the maximum load after the fuel cut when the engine stop condition is satisfied, and then The operating state determination unit 101 determines that the load of the alternator 28 is reduced to a predetermined value and that the alternator 28 is operated at the maximum load during the operation state in which the engine 1 can be restarted only by combustion. When the determination is made, the predetermined first period Ta1 is set. On the other hand, when the operation state determination unit 101 determines that the starter 36 is expected to be used together at the time of restart, the first period Ta1 is shorter than the first period Ta1. The period Ta2 is set to 2. Therefore, in the present embodiment, when the alternator 28 is used to brake the engine 1, the engine 1 can be stopped in a necessary and sufficient braking period. That is, in the operation region where combustion restart is expected, the operation time of the alternator 28 is set to be relatively long, the engine rotation speed Ne is sufficiently reduced, and the engine 1 can be stopped within the intended stop range. In an operation state in which the starter 36 is expected to be used at the time of restart, the operation time of the alternator 28 can be set to a minimum necessary period to prevent lamp flickering due to voltage fluctuations as much as possible. .

1 is a schematic cross-sectional view showing a schematic configuration of a vehicle engine according to a first embodiment of the present invention. 1 is a schematic plan view showing a schematic configuration of a vehicle engine according to a first embodiment of the present invention. It is a control block diagram centering on the engine control unit of the vehicle which concerns on 1st Embodiment of this invention. It is a flowchart which shows an example of the engine automatic stop control which concerns on this embodiment. It is a flowchart which shows an example of the engine automatic stop control which concerns on this embodiment. FIG. 6 is a timing chart showing an engine rotation speed when FIG. 4 and FIG. 5 are executed. It is a flowchart which shows the example of control at the time of the engine restart which concerns on this embodiment.

DESCRIPTION OF SYMBOLS 1 Vehicle engine 12A Stop compression stroke cylinder 12B Stop expansion stroke cylinder 12C Stop intake stroke cylinder 24a Throttle valve 25 Air flow sensor 26 Intake pressure sensor 27 Ignition device 28 Alternator 30, 31 Crank angle sensor 32 Cam angle sensor 33 Water temperature sensor 34 Accelerator opening sensor 35 Ring gear 36 Starter 39 Atmospheric pressure sensor 100 Engine control unit 101 Operating state determination unit 102 Combustion control unit 103 Starter control unit Ta driving period Ta1 first driving period Ta2 second driving period Th throttle opening Th1 First opening during braking Th2 Second opening during braking

Claims (2)

When the predetermined engine stop condition is satisfied, the engine is automatically stopped. When the predetermined restart condition is satisfied after the engine is automatically stopped, the air-fuel mixture is at least in the stop expansion stroke cylinder that was in the expansion stroke when the engine was stopped. In a vehicle engine control apparatus for restarting the engine by burning
An operation state determination unit for determining an operation state of the engine;
A combustion control unit that controls at least the throttle opening, the fuel injection amount, and the injection timing of the engine based on the determination of the operating state determination unit, and that controls the automatic stop and restart control of the engine;
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 driving state determination unit is satisfied when the restart condition is satisfied; and
The combustion control unit, after the engine stop condition is satisfied, when the operation state determination unit determines that the engine is in an operation state in which the engine can be restarted only by combustion when the engine stop condition is satisfied, A rotational speed control process for increasing the idling rotational speed of the engine to a predetermined speed is executed, and the throttle opening degree of the engine after the fuel cut is set to a predetermined first braking opening degree. When the driving state determination unit determines that the electric driving device is expected to be used together, the engine is automatically stopped by a simple stop process that omits the rotation speed control process , and the throttle opening is the vehicle engine, characterized in that to set the lower second braking time opening than the first braking opening Control device. The vehicle engine control device according to claim 1 ,
A generator control unit for controlling the generator of the engine;
When the engine stop condition is satisfied, the generator control unit temporarily sets the generator of the engine to the maximum load after the fuel cut, and then reduces the load of the generator to a predetermined value. In addition, the period during which the generator is operated at the maximum load is set to a predetermined first period when the operation state determination unit determines that the engine is in an operation state where restart of the engine due to combustion alone is expected. On the other hand, when the driving state determination unit determines that the electric driving device is expected to be used together at the time of restart, the second period is set to be shorter than the first period. A control device for a vehicular engine.

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