JP2009030525A - Control device of engine for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimally assist-restart depending on various operational statuses. <P>SOLUTION: When an assist condition is satisfied and the state of a battery 80 is good, a starter motor 36 is driven (step S255), fuel is injected into a stopping time expansion stroke cylinder which is in the expansion stroke in automatic stop of an engine 1 after starting the restart of the engine 1 (step S257), and the engine 1 is restarted. On the other hand, when the assist condition is satisfied and the state of the battery 80 is deteriorated, the fuel is injected into the stopping time expansion stroke cylinder which is in the expansion stroke in the automatic stop of the engine 1 (step S2516), and the starter motor 36 is driven after the restart of the engine 1 (step S2517). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle 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. The present invention relates to a control apparatus for a vehicle engine using a starter motor.

For example, as disclosed in Patent Document 1, in this type of vehicle engine control apparatus, when a predetermined engine stop condition is satisfied, the engine is automatically stopped, and after the engine is automatically stopped, a predetermined restart is performed. It is known that when the condition is established, the engine is restarted by combusting the air-fuel mixture in at least the expansion stroke at the time of stop when the engine is stopped. Here, in an engine control system that employs automatic stop / restart control, if a predetermined restart condition is satisfied after automatic stop, the air-fuel mixture is combusted in the cylinder in the expansion stroke at the time of stop. The engine is restarted in principle, but when the engine is stopped in a state where sufficient torque cannot be obtained by combustion, such as when the piston stop position is too close to the compression top dead center. The engine is restarted by the starter motor.
JP 2004-301080 A

  When restarting the engine with the starter motor, first, starting the engine with the starter motor and then injecting fuel into the cylinder in the expansion stroke and burning it reduces the level of vibration noise (so-called NVH) To preferred. However, conventionally, when the conditions for operating the starter motor are satisfied, the starter motor is operated at the same time as the combustion in the cylinder in the expansion stroke, so that the combustion is preceded by the operation delay of the starter motor itself. As a result, the NVH level could not be lowered sufficiently.

  On the other hand, in an operating situation in which the battery that supplies power to the starter motor has deteriorated, when the starter motor is driven, the effect of the inrush current generated in the starter motor becomes large, and the battery voltage may drop significantly. When such a voltage drop occurs in the battery, actuators and sensor systems that are driven using the battery voltage are also diagnosed as abnormal as the battery voltage decreases, which adversely affects engine control and restart control. There was a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle engine control device capable of optimal assist restart according to various driving situations.

  In order to solve the above problems, the present invention automatically stops the engine when a predetermined engine stop condition is satisfied, and automatically drives the starter motor of the engine when the predetermined assist condition is satisfied after the stop. A vehicle engine control apparatus for automatically restarting an engine, having a battery state determination function for determining a state of a battery that supplies power to the starter motor, and for determining an operation state of the engine And a starter control for driving the starter motor when the assist condition based on the determination of the operation state determination unit is satisfied, and a combustion control unit for controlling combustion of the engine based on the determination of the operation state determination unit And when the assist condition is satisfied and the battery is in good condition, the starter The engine is restarted after starting the engine and the engine is restarted by injecting fuel into the expansion stroke cylinder at the time of stoppage that was in the expansion stroke when the engine was automatically stopped. In this case, when the state of the battery is deteriorated, the starter motor is driven after the engine is restarted by injecting fuel into the stop expansion stroke cylinder that was in the expansion stroke when the engine was automatically stopped. This is a control device for a vehicle engine. In this aspect, a suitable restart control can be achieved according to the state of the battery that supplies power to the starter motor. That is, when the battery is in good condition, the starter motor is first driven during the restart operation when the assist condition is satisfied, and then the air-fuel mixture is burned in the expansion stroke cylinder at the time of stop. The NVH level can be reduced as much as possible. On the other hand, when the battery is in a deteriorated state, priority is given to restarting by combustion, so when the starter motor drives the engine, the engine speed increases to some extent, so the starter motor is rated. As a result of shortening the time required to operate at the speed, the period during which the inrush current flows can be shortened, and an excessive voltage drop can be avoided in the battery.

  In a preferred embodiment, the opening of the throttle valve of the engine is controlled according to the amount controlled by the combustion control unit when power is supplied to the throttle motor that drives the throttle valve, and is predetermined when power is not supplied to the throttle motor. And the battery supplies power to the throttle motor, and the combustion controller is in good condition when the assist condition is satisfied. When the power is supplied to the throttle motor so that the throttle valve is fully closed, the opening / closing control of the throttle motor is stopped so that the power supply to the throttle motor is stopped when the state of the battery is deteriorated. Is controlled based on the determination of the operating state determination unit. In this aspect, when the state of the battery is good, the throttle valve is controlled to be fully closed, so that the so-called blow-up at the time of restart can be prevented and the battery is in a deteriorated state. In some cases, the full closing control of the throttle valve is omitted, so that electric power for driving the starter motor can be secured and power consumption can be saved.

  In a preferred aspect, the operating state determination unit determines at least an internal resistance and a battery capacity of the battery. In this aspect, it is possible to determine the deterioration of the battery based on the internal resistance, and it is possible to determine the appropriate drive of the starter motor based on the battery capacity.

  In a preferred aspect, the combustion control unit causes the engine to temporarily burn by performing combustion in a stop-time compression stroke cylinder that is in a compression stroke when stopped when the piston stop position of the engine that is automatically stopped is within a predetermined appropriate range. After the reverse rotation, the engine that has been reversely rotated by causing combustion in the expansion stroke cylinder at the time of stoppage in the expansion stroke at the time of normal rotation is rotated forward, while the piston stop position of the engine that is automatically stopped is out of the appropriate range. When the engine is in the stop-time expansion stroke cylinder, the engine immediately rotates in the normal direction, and the starter control unit causes the engine in the stop-time expansion stroke cylinder to perform combustion to immediately correct the engine. In the case of rolling driving, the starter motor is driven and controlled. In this aspect, when the piston stop position is stopped in an appropriate range, restart by only combustion is performed by a so-called reverse rotation restart method, and the use frequency of the starter motor can be reduced to save battery energy. .

  As described above, according to the present invention, optimal assist restart such as giving priority to the reduction of the NVH level or giving priority to avoiding an excessive voltage drop of the battery according to the state of the battery that drives the starter motor. There is a remarkable effect that it can be achieved.

  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 102 (see FIG. 4) 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. This common intake passage 21c is provided with a throttle body (not shown). The throttle body includes a throttle valve 23 that can adjust the amount of air flowing into each of the cylinders 12A to 12D, a throttle motor 24 that drives the throttle valve 23, and an idling speed control device (ISC: Idling Speed Control device) (not shown). ) And are provided. The throttle valve 23 is energized in a direction slightly opening the common intake passage 21c from a fully closed state by a spring (not shown). When the throttle motor 24 is not energized, the common intake passage 21c is opened at a predetermined reference opening. When the throttle motor 24 is energized, it is configured to open from fully closed to fully open according to the control amount.

  An air flow sensor 25 for detecting the intake air flow rate and an intake air temperature sensor 29 for detecting the intake air temperature are installed on the upstream side of the throttle valve 23, and an intake pressure sensor 26 for detecting the intake air pressure is installed on the downstream side. ing.

  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 adjusting the output voltage by controlling the current of a field coil (not shown), and the engine control unit 100 (FIG. 4) input to the regulator circuit 28a. Based on the control signal from the reference), the power generation amount corresponding to the voltage of the electric load 82 (see FIG. 3) of the vehicle and the battery 80 (see FIG. 3) mounted on the vehicle is executed. .

  The engine 1 is provided with a starter motor 36. The starter motor 36 has a motor main body 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 body 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 motor 36 is used to start the engine, the pinion gear 36d moves to a predetermined meshing position and meshes with the ring gear 35, whereby the crankshaft 3 is rotationally driven. (Cranking).

  There are two forms in which the engine is started by the starter motor 36. In the first mode, the driver turns the ignition key switch (IG key SW38, see FIG. 4) to drive the starter motor 36, thereby starting the engine 1, which is called key start. In the second mode, the starter control unit 103 (see FIG. 4) of the engine control unit 100 automatically drives the starter motor 36 at the restart after the engine is automatically stopped, thereby starting the engine 1. is there.

  The engine 1 is provided with two crank angle sensors 30 and 31 for detecting 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 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 schematic configuration diagram of a power supply system mounted on the vehicle according to the present embodiment.

  Referring to FIG. 3, the power supply system includes a battery 80.

  The battery 80 is always connected to the starter motor 36 and other vehicle electric loads 82, and can supply power thereto. The vehicle electric load 82 includes an airbag control unit such as the throttle motor 24 described above, an EHPAS (electrohydraulic power steering) control unit, a navigation system, audio, various meters, various lights, defogger, hill holder, electric power Examples include a steering motor.

  At the time of key start and when restarting by cranking from the engine automatic stop state, electric power is supplied from the battery 80 to the motor body 36a of the starter motor 36, and the starter motor 36 is driven. At the time of this cranking, since the power consumption in the starter motor 36 is relatively large, the power supply voltage of the battery 80 is temporarily greatly reduced. Therefore, in this embodiment, the state of the battery 80 is diagnosed by an engine control unit 100 described later, and the diagnosis result is provided to engine control. In this embodiment, a battery temperature sensor Sa that detects the temperature of the battery 80 is attached to make the state determination of the battery 80 precise.

  As shown in FIG. 3, the engine 1 according to the present embodiment constitutes a power unit together with the automatic transmission 2.

  FIG. 4 is a control block diagram centering on the vehicle engine control unit 100 according to the present invention. In FIG. 4, 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, an intake air temperature sensor 29, a crank angle sensor 30, 31, a cam angle sensor 32, a water temperature sensor 33, an accelerator opening degree. Signals from input elements such as the sensor 34 and the IG key switch 38 are input.

  The engine control unit 100 outputs control signals to output elements such as the fuel injection valve 16, the throttle motor 24, the ignition device 27, the alternator 28, the starter motor 36, and the vehicle electric load 82 that are the control targets.

  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 an operating state determination unit 101, a combustion control unit 102, a starter control unit 103, and an alternator control unit 104.

  Based on detection signals from input elements such as various sensors 25, 26, 29, 30, 31, 32, 34, and Sa of the engine 1, the operating state determination unit 101 determines the engine speed Ne, the in-cylinder temperature, Alternatively, various operating states such as 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, as the operation state determined by the operation state determination unit 101, the in-cylinder temperature of each cylinder estimated based on data stored in advance in memory, the automatic engine stop condition, the restart condition, the success or failure of the assist condition Is also included. The assist condition refers to a condition in which a start assist by the starter motor 36 is required, for example, when the stop position of the piston 13 is out of a predetermined stop position stored in advance in the memory.

  In the present embodiment, the driving state determination unit 101 is programmed to execute the state determination of the battery 80.

  The determination of the state of the battery 80 is to determine at least the internal resistance R and the battery capacity Qv of the battery 80.

The internal resistance R is used to determine the deterioration state of the battery 80 and can be obtained from the terminal voltage Vn of the battery 80 and the discharge current I. For example, if the terminal voltage when the battery capacity is 100% is the reference voltage V and the terminal voltage and the discharge current at the time of determination are Vn and I, the internal resistance R is R = (V−Vn) / I (1)
The deterioration of the battery 80 can be evaluated by comparing the internal resistance R with a reference value stored in advance in the memory. In general, when the temperature of the battery is low, the internal chemical change is difficult to proceed, and the internal resistance R is increased, so that the voltage drop due to use proceeds faster. Therefore, it is programmed to perform appropriate deterioration determination according to the temperature by mapping data that corrects the terminal voltage Vn of the equation (1) according to the temperature detected by the battery temperature sensor Sa. Yes.

  Further, the battery capacity Qv can be obtained based on the terminal voltage Vn and the reference voltage V. Even in this case, it is programmed so that the battery capacity Qv can be estimated appropriately according to the temperature by mapping a coefficient that corrects the terminal voltage Vn according to the temperature detected by the battery temperature sensor Sa. ing.

  In the present embodiment, the operating state determination unit 101 is also configured to calculate the position of the piston 13 based on signals from the crank angle sensors 30 and 31. This function also determines the stop position of the piston 13 when the engine 1 is automatically stopped.

  The combustion control unit 102 sets an appropriate throttle opening (intake amount) of the engine 1, a fuel injection amount and its injection timing, and an appropriate ignition timing, and controls the fuel injection valve 16, the throttle motor 24, and the ignition device 27. It is a module. Due to the function of the combustion control unit 102, the engine control unit 100 as a whole automatically stops the engine 1 when a predetermined automatic stop condition is satisfied, and when the predetermined restart condition is satisfied after the stop, 1 is automatically restarted. The restart control according to the present embodiment is a combustion that automatically restarts the engine by combustion in the stop-time expansion stroke cylinder that was in the expansion stroke when the engine 1 was automatically stopped when the restart condition was satisfied. Either the restart control or the starter combined restart control using the starter motor 36 is selected and executed. When restarting combustion, the air-fuel mixture is combusted in the stop-time compression stroke cylinder to reverse the engine 1 once, and then the air-fuel mixture is combusted in the stop-time expansion stroke cylinder to return the engine 1 to normal rotation. A reverse restart method is adopted. On the other hand, when the starter combined restart control is performed, the air-fuel mixture is immediately combusted in the expansion stroke cylinder when stopped.

  The starter control unit 103 sends a drive signal to the starter motor 36 to drive the starter motor 36 when the starter motor 36 is required to be driven at the time of key start and restart in the engine automatic stop control. The pinion gear 36d is meshed with the ring gear 35 fixed to the flywheel, and the rotational force of the motor body 36a is transmitted to the flywheel via the pinion gear 36d and the ring gear 35, thereby forcibly starting the engine. And a module for stopping the drive of the engine 1 by the starter motor 36 when a predetermined condition is satisfied.

  The alternator control unit 104 is a module that sets an appropriate power generation amount of the alternator 28 and outputs the drive signal to the regulator circuit. The alternator control unit 104 normally feedback-controls the amount of power generation so that a target value (eg, 13 V) of the output voltage (regulated voltage) is set, and the target value is maintained even if the engine speed changes. . In the power generation amount control, the alternator control unit 104 performs control such that the load of the engine 1 is changed by adjusting the power generation amount of the alternator 28 and the piston 13 stops in an appropriate range suitable for restart. ing.

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

  FIG. 5 is an explanatory diagram showing the relationship between the stop-time compression stroke cylinder and the air amount according to the present invention.

  Referring to FIG. 5, the memory of engine control unit 100 stores a combustion restart appropriate range A determined in advance by a bottom dead center limit and a top dead center limit that can be restarted by combustion as a control map. ing. The appropriate combustion restart range A is set, for example, in a range from 80 ° before compression top dead center to 60 ° before compression top dead center.

  In the present embodiment, when the engine 1 is automatically stopped during idling, first, the fuel is cut at a predetermined rotational speed slightly higher than the idle rotational speed so that the scavenging of each cylinder 12A to 12D is sufficiently performed. Then, the throttle valve 23 is opened for a predetermined period thereafter, and control is performed so that the opening degree is set in advance. The throttle valve 23 is closed at an appropriate timing set in advance. As a result, the amount of air sucked into the stop expansion stroke cylinder and the stop compression stroke cylinder is sufficiently increased, and the amount of air in the expansion stroke cylinder is slightly greater than that of the compression stroke cylinder. As a result, the piston 13 of the expansion stroke cylinder is suitable for restarting somewhat closer to the bottom dead center (bottom dead center) from the center of the stroke due to the balance of the compression pressure of the air in the two cylinders driven at the time of restart. Control is performed so as to stop within the appropriate range A for restarting combustion. However, the stop position of the piston 13 is determined by the balance of the air amount in each of the cylinders 12A to 12D. Therefore, the relationship between the engine rotational speed Ne and the stop position of the piston 13 may change in accordance with individual differences of the engine 1, changes in the temperature of the engine 1, and atmospheric conditions. In such a case, even if the alternator 28 is controlled based on the relationship between the preset engine speed Ne and the stop position of the piston 13 to adjust the engine speed Ne, the stop position of the piston 13 can be set to a desired value. Cannot be in position. Therefore, in the present embodiment, as shown in a flowchart described later, when the piston stop position determined by the operation state determination unit 101 is out of the combustion restart appropriate range A, the starter control unit 103 is The starter motor 36 is configured to be driven.

  Next, automatic stop control performed by the engine control unit 100 will be described.

  6 and 7 are flowcharts centering on control by the engine control unit 100, particularly automatic stop control. FIG. 6 shows the control until the engine 1 stops, and FIG. 7 shows the subsequent restart control.

  Referring to FIG. 6, engine control unit 100 waits for a preset engine automatic stop condition to be satisfied (step S10). 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 S11). Specifically, it waits for the engine speed Ne to be adjusted to the pre-stop speed N1 (for example, 760 rpm) (step S12). Then, after the engine rotational speed Ne becomes N1 (YES in step S12), the fuel supply from the fuel injection valve 16 is stopped (step S14).

  Subsequently, the engine control unit 100 drives the throttle motor 24 to open the throttle valve 23 (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 23 (step S17). Thereafter, the engine control unit 100 continues the alternator control and continues to adjust the stop position of the piston 13, and waits for the engine 1 to completely stop based on the detected values of the crank angle sensors 30, 31 (step S18). ). The engine control unit 100 continues to control the stop position adjustment of the piston 13 until the engine 1 is completely stopped. When the engine 1 is completely stopped, the alternator control is ended (step S19), and the crank angle is controlled. The stop position of the piston 13 determined by the operating state determination unit 101 based on the detection of the sensors 30 and 31 is stored (step S20).

  Next, the restart of the engine 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 the piston 13 of the stop-time compression stroke cylinder is within the combustion restart appropriate range A (step S22). If the piston 13 is within the combustion restart appropriate range A, the engine control unit 100 executes the combustion restart subroutine as it is (step S23), and further executes the normal operation subroutine (step S24). As for details of the combustion restart control according to the present embodiment, for example, those disclosed in Japanese Patent Laid-Open No. 2005-2847 and Japanese Patent Laid-Open No. 2005-315197 previously proposed by the present applicant are used as they are. Since it is possible to apply, description is abbreviate | omitted about the detail.

  On the other hand, if it is determined in step S22 that the piston 13 is outside the combustion restart appropriate range A, the engine control unit 100 executes an assist combined restart subroutine (step S25).

  FIG. 8 is a flowchart showing an assist restart subroutine in the flowchart of FIG.

  Referring to FIG. 8, in the assist restart subroutine, engine control unit 100 determines the state of the battery from battery temperature, terminal voltage Vn, and discharge current I based on the above-described equation (1) and the like (step S251). . Next, fuel is injected into the stop-time expansion stroke cylinder to prepare for combustion (step S252). In this state, the engine control unit 100 determines the quality from the determined battery state (internal resistance R, battery capacity Qv) (step S253). If it is determined that the state of the battery 80 is good, the combustion control unit 102 operates the throttle motor 24 to fully close the throttle valve 23 in order to prevent the blow-up. After the throttle valve 23 is fully closed, the starter control unit 103 of the engine control unit 100 drives the starter motor 36. Then, the engine control unit 100 determines the movement of the piston 13 based on whether or not the edges of the crank angle sensors 30 and 31 (rise or fall of the crank angle signal) are detected by driving the starter motor 36 (step). S256). When it is detected that the piston 13 is displaced and the engine 1 is operated, the combustion control unit 102 executes control for igniting the air-fuel mixture in the expansion stroke cylinder at the time of stop (step S257), and then compression top dead Fuel injection control is executed for the compression stroke cylinder when the piston 13 passes through the point (step S258). Thereafter, the combustion control unit 102 waits for the piston 13 to pass the compression top dead center (step S259), and executes the ignition control of the stop-time compression stroke cylinder when the piston 13 passes the compression top dead center (step S259). S2510). The ignition timing in the compression stroke cylinder at the time of stop is preferably controlled so as to be retarded by a predetermined crank angle, and is controlled so as to further suppress the blow-up.

  Thereafter, the engine control unit 100 determines whether or not the engine 1 has completely exploded within a predetermined time (step S2511). Specifically, based on the detection values of the crank angle sensors 30 and 31, the engine 1 waits for the rotational speed of the engine 1 to be 500 rpm or more, and is determined to be complete explosion at 500 rpm or more.

  When the engine 1 is completely detonated, the starter control unit 103 stops driving the starter motor 36 (step S2512). Thereafter, the engine control unit 100 determines whether or not the power supply to the throttle motor 24 is cut off (step S2513), and if it is cut off, the throttle valve 23 is fully closed to prevent further blow-up. After planning (step S2514), the operation is shifted to the normal operation and the assist restart control is ended.

  As described above, when the starter motor 36 is operated before the ignition in the stop-time expansion stroke cylinder is executed, the sound when the pinion gear 36d of the starter motor 36 meshes with the ring gear 35 can be reduced. Therefore, the NVH level can be reduced as much as possible.

  On the other hand, when it is determined in step S253 that the state of the battery 80 is defective, first, the combustion control unit 102 cuts off the energization to the throttle motor 24 (step S2515) and secures the electromotive force of the battery 80. . Then, first, ignition control of the expansion stroke cylinder at the time of stop is executed (step S2516), and then the starter control unit 103 controls driving of the starter motor 36 (step S2517), and the process proceeds to step S258. It has become.

  As described above, according to the present embodiment, suitable restart control can be achieved according to the state of the battery 80 that supplies power to the starter motor 36. That is, when the battery 80 is in a good state, the starter motor 36 is first driven at the time of the restart operation in which the assist condition is satisfied, and then the air-fuel mixture is combusted in the expansion stroke cylinder at the time of stop. And the NVH level can be reduced as much as possible. On the other hand, when the battery 80 is in a deteriorated state, priority is given to restarting by combustion. Therefore, when the starter motor 36 drives the engine 1, the rotational speed of the engine 1 is increased to some extent. As a result of shortening the time until the starter motor 36 operates at the rated speed, the period during which the inrush current flows can be shortened, and an excessive voltage drop in the battery 80 can be avoided.

  Further, in this embodiment, the throttle valve 23 is controlled in opening degree according to the control amount by the combustion control unit 102 when the power is supplied to the throttle motor 24 that drives the throttle valve 23, and the throttle motor 24 is not connected to the throttle motor 24. When supplying power, the intake passage 21 is opened at a predetermined reference opening, the battery 80 supplies power to the throttle motor 24, and the combustion control unit 102 determines the state of the battery 80 when the assist condition is satisfied. When the condition of the battery 80 is good, power is supplied to the throttle motor 24 so that the throttle valve 23 is fully closed. On the other hand, when the state of the battery 80 is deteriorated, the power supply to the throttle motor 24 is stopped. The open / close control of 24 is controlled based on the determination of the operation state determination unit 101. For this reason, in this embodiment, when the state of the battery 80 is good, the throttle valve 23 is controlled to be fully closed, so that the so-called blow-up at the time of restart can be prevented, and the battery When 80 is in a deteriorated state, the full closing control of the throttle valve 23 is omitted, so that power for driving the starter motor 36 can be secured and power consumption can be saved. .

  In the present embodiment, the operating state determination unit determines at least the internal resistance R and the battery capacity Qv of the battery 80. Therefore, in this embodiment, it is possible to determine the deterioration of the battery 80 based on the internal resistance R, and it is possible to determine appropriate driving of the starter motor 36 based on the battery capacity Qv.

  Further, in the present embodiment, the combustion control unit 102 causes combustion in the stop compression stroke cylinder that is in the compression stroke at the stop when the piston stop position of the engine 1 that is automatically stopped is in the predetermined appropriate range A. After the engine 1 has been reversely rotated once, the engine 1 that has been reversely rotated is made normal by causing combustion in the stop expansion stroke cylinder that is in the expansion stroke at the time of stop, while the piston stop position of the engine 1 that is automatically stopped is appropriate When it is out of the range A, combustion is performed in the expansion stroke cylinder when stopped and the engine 1 is immediately forward rotated. The starter control unit 103 performs combustion in the expansion stroke cylinder when stopped and causes the engine 1 to perform combustion. The starter motor 36 is driven and controlled when the motor is immediately forward driven. For this reason, in this embodiment, when the piston stop position is stopped in the appropriate range A, restart by only combustion is performed by a so-called reverse rotation restart method, and the use frequency of the starter motor 36 is reduced. Energy saving can be achieved.

  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.

  For example, a two-battery system having a main battery and a sub-battery is adopted as the power supply system, and the throttle motor 24 is operated by the main battery and the starter motor 36 is operated by the sub-battery. It goes without saying that various changes can be made within the range.

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 schematic block diagram of the electric power supply system mounted in the vehicle which concerns on this embodiment. It is a control block diagram centering on the control unit of the vehicle which concerns on this invention. It is explanatory drawing which shows the relationship between the compression stroke cylinder at the time of stop which concerns on this invention, and air quantity. 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. It is a flowchart which shows the assist restart subroutine in the flowchart of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle engine 12A-12D Cylinder 13 Piston 23 Throttle valve 24 Throttle motor 35 Ring gear 36 Starter motor 80 Battery 82 Vehicle electric load 100 Engine control unit 101 Operation state determination part 102 Combustion control part 103 Starter control part A Combustion restart appropriateness Range I Discharge current Ne Engine speed Qv Battery capacity R Internal resistance Sa Battery temperature sensor V Reference voltage Vn Terminal voltage

Claims (4)

A vehicle engine that automatically stops the engine when a predetermined engine stop condition is satisfied, and automatically restarts the engine by driving the starter motor of the engine when the predetermined assist condition is satisfied after the stop. A control device of
An operation state determination unit that has a battery state determination function for determining a state of a battery that supplies power to the starter motor, and that determines an operation state of the engine;
A combustion control unit that controls combustion of the engine based on the determination of the operating state determination unit;
A starter controller that drives the starter motor when the assist condition based on the determination of the driving state determination unit is satisfied,
When the assist condition is satisfied and the battery is in a good state, the starter motor is driven to start the engine restart, and then the expansion at the stop is in the expansion stroke when the engine is automatically stopped. When the engine is restarted by injecting fuel into the stroke cylinder and the assist condition is satisfied, if the state of the battery is deteriorated, the expansion at the time of stop that was in the expansion stroke at the time of the automatic stop of the engine A vehicle engine control device that drives the starter motor after injecting fuel into a stroke cylinder and restarting the engine. The vehicle engine control device according to claim 1,
The opening of the throttle valve of the engine is controlled according to the amount controlled by the combustion control unit when power is supplied to the throttle motor that drives the throttle valve, and a predetermined reference opening when the power is not supplied to the throttle motor. Is to open the intake passage,
The battery supplies power to the throttle motor,
When the assist condition is satisfied, the combustion control unit supplies power to the throttle motor so that the throttle valve is fully closed when the battery state is good, while the battery state deteriorates. And controlling the opening / closing of the throttle motor based on the determination of the operating state determination unit so as to stop the power supply to the throttle motor. . The control device for a vehicle engine according to claim 1 or 2,
The driving state determination unit determines at least an internal resistance and a battery capacity of the battery. The control device for a vehicle engine according to any one of claims 1 to 3,
When the piston stop position of the engine that is automatically stopped is within a predetermined appropriate range, the combustion control unit causes the engine to perform combustion in a compression stroke at the time of stoppage that is in the compression stroke at the time of stop, and temporarily reverses the engine After that, when the engine that has been reversely rotated by causing combustion in the expansion stroke cylinder at the stop in the expansion stroke at the time of stop is rotated forward, the piston stop position of the engine that is automatically stopped is out of the appropriate range. Combustion is performed in the expansion stroke cylinder at the time of stop, and the engine is immediately forward rotated.
The starter control unit drives and controls the starter motor when combustion is performed in the expansion stroke cylinder at the time of stop and the engine is immediately driven to rotate forward.

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