JP4665940B2 - Control device for vehicle engine - Google Patents

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 vehicle engine control device using an electric drive device.

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. Here, in an engine control system that employs automatic stop / restart control, it is necessary to use a starter as an electric drive device that assists the engine relatively frequently when the engine is automatically restarted. For this reason, in the configurations of Patent Documents 1 and 2, a two-battery system including a main battery and a sub-battery is adopted, and a normal start based on a driver's operation (mainly an ignition switch operation) and an automatic restart based on the control. The power supply capability is improved by switching the battery that supplies power at the start.
Japanese Patent No. 3812259 JP 2005-36795 A

  In the above-described prior art, the deterioration state of the battery that supplies power to the electric drive device is determined, and when deterioration is recognized, power is only supplied from another battery.

  However, among the batteries, the main battery is usually also used for power supply of an electric load mounted on the vehicle. Therefore, when the power supply circuit is switched in a predetermined operation state, the vehicle is prevented from moving backward. There is a problem that there is a concern about power reduction to the automatic locking brake mechanism (so-called hill holder).

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a vehicular engine control device capable of improving the startability of an automatically stopped engine while preventing involuntary movement of the vehicle. Yes.

  In order to solve the above problems, the present invention is provided in a vehicle equipped with an automatic locking brake mechanism that restricts involuntary movement at the time of stop, and automatically stops the engine when a predetermined automatic stop condition is satisfied. In a vehicle engine control device that automatically restarts an engine after automatic stop when a predetermined restart condition is satisfied, an operating state determination unit that determines the operating state of the engine, and a stopped engine An electric drive device capable of assisting start-up, an electric drive device control unit that drives the electric drive device when a predetermined assist condition based on the determination of the operation state determination unit is satisfied when the restart condition is satisfied, and at least A first battery that supplies power to the electric load of the vehicle including the automatic locking brake mechanism, a second battery that supplies power to the electric drive device, and at least In addition, by switching the circuit connection between the battery deterioration detection means for detecting the deterioration state of the second battery and the first and second batteries and the electric drive device, the electric drive is performed only from the second battery. Switching means for switching the power supply mode between a normal power supply mode for supplying power to the apparatus and a supplementary power supply mode for supplying power to the electric drive device from the first battery together with the second battery, and detecting information related to the reverse of the vehicle And a reverse information detection means for outputting to the driving state determination unit, and the driving state determination unit determines whether or not the power supplied to the automatic lock brake mechanism is allowed to decrease based on the output of the reverse information detection means. And the switching means detects the deterioration of the second battery when the assist condition is satisfied. In this case, the vehicle is characterized in that the power supply mode is switched to the supplementary power supply mode only when the driving state determination unit allows a decrease in power supplied to the automatic lock brake mechanism. An engine control device. In this aspect, when the assist condition is satisfied and the battery drive is detected when the electric drive device is driven when the engine is restarted, the automatic lock brake mechanism is applied to the vehicle based on the information related to the reverse of the vehicle. The power supply mode is switched to the supplementary power supply mode only in the operating state in which the reduction of the supplied power is allowed. For this reason, by switching the power supply mode to the supplementary power supply mode, the vehicle does not move involuntarily even if the power supplied to the automatic lock brake mechanism decreases.

  In a preferred aspect, when the assist condition is satisfied, the battery deterioration detection unit detects the deterioration of the second battery, and the driving state determination unit is configured to supply power to the automatic lock brake mechanism. There is an alarm means for issuing an alarm to the occupant when the lowering is prohibited. In this mode, when the engine is restarted, the vehicle operation is such that the power supply to the automatic lock brake mechanism can be stopped by issuing an alarm to the occupant in an operating situation in which the electric drive device cannot sufficiently function due to deterioration of the battery. The startability of the engine can be improved while preventing the vehicle from involuntarily moving backward.

  In a preferred aspect, the reverse information detecting means is constituted by either a brake hydraulic pressure sensor for detecting an operating hydraulic pressure of a brake device of the vehicle or an inclination angle sensor for detecting a road surface gradient. In this aspect, the backward information can be detected using a sensor that is already installed in a normal vehicle, and can be used for power supply mode switching control with an inexpensive configuration.

  In a preferred aspect, the switching means switches the power supply mode to the supplementary power supply mode even when the ignition key switch of the engine is connected. In this aspect, the startability can be improved even when the engine is started based on the operation of the operator.

  As described above, according to the present invention, when the deterioration of the second battery is detected when the assist condition is satisfied, the power supply mode is limited to the operation state in which the decrease in the power supplied to the automatic lock brake mechanism can be allowed. Since the startability of the engine by the switching and the electric drive device is ensured, there is a remarkable effect that the startability of the automatically stopped engine can be improved while preventing involuntary movement of the vehicle.

  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. A throttle body 24 is provided in the common intake passage 21c. The throttle body 24 includes a throttle valve 24a that can adjust the amount of air flowing into each cylinder 12A to 12D, an actuator 24b that drives the throttle valve 24a, and an idling speed control device (ISC) 24c. And are 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. 4) 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 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 control of the amount of power generation corresponding to the voltage of the vehicle electrical load 82 (see FIG. 3) and the battery 80 (see FIG. 3) 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 1, the pinion gear 36d moves to a predetermined meshing position and meshes with the ring gear 35, so that the crankshaft 3 is driven to rotate. ing.

  There are two modes for starting the engine by the starter 36. In the first mode, the driver turns the ignition key switch 38 (see FIG. 3) 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. 4) 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. This is called automatic restart.

  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.

  The vehicle according to the present embodiment is provided with an inclination angle sensor 41 as reverse information detection means. The inclination angle sensor 41 outputs a signal related to the road surface gradient as information relating to the reverse of the vehicle, and inputs the information to the engine control unit 100. As a result, the engine control unit 100 can recognize the gradient of the road surface and determine whether or not the power supplied to the hill holder 110 can be lowered.

  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 first battery 80a and a second battery 80b (referred to collectively as battery 80).

  The first battery 80a is always connected to the vehicle electrical load 82 and can be supplied with electric power. The vehicle electrical load 82 is roughly divided into a first load group 82a, a second load group 82a, and a third load group 82c.

  The first load group 82a is an electrical load in which it is not desirable for the power supply voltage to temporarily decrease during cranking of the starter 36 among general vehicle electrical loads. Specific examples include an airbag control unit, an EHPAS (electrohydraulic power steering) control unit, a navigation system, audio, and various meters.

  The second load group 82a is an electric load that does not pose a problem even if the power supply voltage decreases temporarily during cranking of the starter 36, among general vehicle electric loads. Specific examples include various lights and defoggers.

  The third load group 82c is a vehicle electrical load unique to the vehicle on which the vehicle engine control device is mounted. Specifically, there are a hill holder 110 as an automatic locking brake mechanism that prevents the vehicle from slipping down on a slope stop, a motor of an electric power steering, and the like. The hill holder 110 covers that the power brake does not operate during the engine automatic stop, and the electric power steering covers that the EHPAS (electrohydraulic power steering) does not operate during the engine automatic stop. . In order to control the hill holder 110, the vehicle is provided with a brake booster negative pressure sensor 39 for detecting a brake booster negative pressure introduced into the brake booster of the vehicle and a brake hydraulic pressure sensor 40 for detecting the pressure of the hydraulic fluid of the brake pedal. ing. The more detailed configuration of the hill holder 110 is the same as that disclosed in detail in Japanese Patent Application No. 2003-25669 (Japanese Patent Laid-Open No. 2004-231155) previously proposed by the present applicants. This is omitted for the rest of the description.

  The first battery 80 a is connected to the starter 36 via the power relay 85. Therefore, when the power relay 85 is off, power is not supplied to the starter 36, and when the power relay 85 is on, power can be supplied to the starter 36. Further, the first battery 80a is always connected to the alternator 28, and electricity generated by the alternator 28 is charged to the first battery 80a. The voltage of the first battery 80a is detected by the first voltage sensor SW1 and input to the engine control unit 100.

  The second battery 80b has a smaller capacity than the first battery 80a and is dedicated to driving the starter 36. The second battery 80b is always connected to the starter 36 and can supply power. The second battery 80 b is connected to the alternator 28 via the charge relay 87. Thereby, when the charge relay 87 is on, the electricity generated by the alternator 28 is charged to the second battery 80b. The voltage of the second battery 80b is detected by the second voltage sensor SW2 and input to the engine control unit 100.

  At the time of key start and when restarting by cranking from the engine automatic stop state, power is supplied from the second battery 80b to the motor 36a of the starter 36, and the starter 36 is driven.

  At the time of cranking, since the power consumption in the starter 36 is relatively large, the power supply voltage of the second battery 80b temporarily decreases significantly (see FIG. 5). However, since the vehicle electrical load 82 is supplied with power from the first battery 80a, it is not affected by the voltage drop of the second battery 80b. This is particularly effective for the first load group 82a in which a decrease in power supply voltage is not desirable.

  Moreover, the warning alerting | reporting part 90 is provided in the vehicle which concerns on this embodiment. This informs the driver of various warnings (warnings) such as running out of oil, and is generally a warning lamp or the like arranged in the instrument panel.

  Further, a buzzer 92 (see FIG. 4) is provided in the instrument panel so that an alarm can be issued to the occupant under the control of the engine control unit 100.

  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, a crank angle sensor 30, 31, a cam angle sensor 32, a water temperature sensor 33, an accelerator opening sensor 34, an ignition key. Signals from input elements such as the switch 38, the booster negative pressure sensor 39, the brake hydraulic pressure sensor 40, and the tilt angle sensor 41 are input.

  Further, the engine control unit 100 outputs the fuel injection valve 16, the throttle valve 24a, the ignition device 27, the alternator 28, the starter 36, the vehicle electrical load 82 including the hill holder 110, the power relay 85, the charge relay 87, and the like that are the control targets. Output a control signal to the element.

  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 includes an operation state determination unit 101, a combustion control unit 102, a starter control unit 103, an alternator control unit 104, a power supply state determination unit 105, an electric load control unit 106, a relay control unit 107, a warning processing unit 108, In addition, the buzzer control unit 109 is logically configured.

  The operating state determination unit 101 determines the position of the piston 13 based on sensor signals from the airflow 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, and the success or failure of assist conditions. The assist condition refers to a condition in which a start assist by the starter 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.

  The combustion control unit 102 performs proper throttle opening of the engine 1 based on sensor signals from the airflow 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. 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. 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 12B that was in the expansion stroke when the engine 1 was automatically stopped when the restart condition was satisfied. One of the control methods of the restart control, the starter combined restart control using the starter 36 in combination, and the starter start control for forcibly restarting the engine only by the starter 36 is selected and executed.

  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.

  The alternator control unit 104 sets an appropriate power generation amount of the alternator 28 and outputs the drive signal to the regulator circuit. Usually, a target value (for example, 13V) of the output voltage (regulated voltage) is set, and the power generation amount is feedback-controlled so that the target value is maintained even if the engine speed or the like fluctuates. 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. While the power generation amount control is being performed, the output voltage varies according to the power consumption of the electric load 82.

  The power supply state determination unit 105 determines the voltage from each of the batteries 80a and 80b based on the detection values of the voltage sensors SW1 and SW2. As will be described in detail later, the power supply state determination unit 105 also performs deterioration determination of the batteries 80a and 80b.

  The electric load control unit 106 operates the vehicle electric load 82 or changes its operating state based on a switch operation of a driver or a passenger or automatically. In order to secure more power supply to the starter 36 when the starter is driven, the power supply to the vehicle electrical load 82 is cut off as necessary. In the present embodiment, the operation of the hill holder 110 is also controlled based on the outputs of the crank angle sensors 30 and 31, the booster negative pressure sensor 39, the brake hydraulic pressure sensor 40, and the tilt angle sensor 41. On the other hand, the driving state determination unit 101 processes a signal related to the road surface gradient input from the inclination angle sensor 41 based on the operating state of the hill holder 110 as information related to the backward movement of the vehicle, thereby supplying power to the hill holder 110. It is configured to determine whether or not the lowering is allowed.

  The relay control unit 107 controls power supply to the starter 36 and charge control of the battery 80 by performing on / off control of the power relay 85 and the charge relay 87 shown in FIG. 3 as necessary. In the present embodiment, the relay control unit 107 switches the connection cut-off state of the power relay 85, so that the normal power supply mode in which power is supplied to the starter 36 only from the second battery 80b, and the first battery together with the second battery 80b. Switching means for switching to the supplementary power supply mode for supplying power to the starter 36 also from the battery 80a is configured. The relay control unit 107 maintains the power supply mode in the normal power supply mode by cutting off the power relay 85 when the combustion restart control (or automatic restart control) is executed.

  The warning processing unit 108 operates the warning notification unit 90 when the driving state determined by the driving state determination unit 101 is predetermined.

  The buzzer control unit 109 is a case where the driving state determined by the driving state determination unit 101 detects the deterioration of the second battery 80b when the assist condition is satisfied, and the driving state determination unit 101 is connected to the hill holder 110. The buzzer 92 is activated when a decrease in the power supply is prohibited.

  Next, deterioration determination of the battery 80 according to the present embodiment by the power supply state determination unit 105 will be described.

  FIG. 5 is a timing chart for explaining battery deterioration determination. Note that FIG. 5 shows a timing chart of the second battery 80b as an example of the battery. However, since the deterioration determination can be performed for the first battery by the same method, the second battery 80b is used here. The battery 80b will be described as an example.

  Referring to FIG. 5, when power supply is started to an electric load that requires a large amount of power, such as starter 36, second battery 80 b suddenly drops in voltage from a specified voltage, and has a certain transient state. After the period, the behavior returns to the specified voltage again. In the normal state where the second battery 80b is not deteriorated, the transiently reduced voltage maintains the predetermined height and returns to the specified voltage, whereas in the deteriorated deterioration state, the voltage is transient. It has been found that the reduced voltage is lower than normal.

  Therefore, in this embodiment, a deterioration determination voltage Vst for detecting battery deterioration is set in advance through experiments or the like, and the deterioration state of the battery 80 is determined by comparing the deterioration determination voltage Vst with the detected voltage (sub_vb). I am doing so. The deterioration determination voltage Vst is set to a predetermined voltage (for example, 6V to 8V) that can be taken by the currently detected voltage (sub_vb). If the voltage (sub_vb) detected by the voltage sensors SW1 and SW2 is less than the deterioration determination voltage Vst, it is determined that the battery 80 is deteriorated.

  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 automatic stop condition for engine 1 to be satisfied (step S10). Specifically, when the brake operating state continues for a predetermined time and the vehicle speed is equal to or lower than a predetermined value, it is determined that the automatic stop condition of the engine 1 is satisfied. If it is determined in step S10 that the automatic stop condition is satisfied, the engine control unit 100 starts engine rotation speed adjustment control including alternator control (step S12).

  Specifically, the engine rotation speed Ne is adjusted to the rotation speed N1 before stop (for example, 760 rpm) (step S13). 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). 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 that the piston 13 of the stop-time compression stroke cylinder 12A is within a predetermined single combustion stop range R (for example, a range from 60 ° CA to 80 ° CA before compression top dead center). It is determined whether or not there is (step S22). If the piston 13 is within the single combustion stop range R, the engine control unit 100 executes the combustion restart subroutine as it is (step S23), and further executes the normal operation subroutine (step S24). On the other hand, when it is determined in step S22 that the piston 13 is outside the single combustion stop range R, the engine control unit 100 further determines that the piston stop position is within a predetermined combustion restartable range A (for example, before compression top dead center). It is determined whether the angle is within a range of 140 ° to 40 ° before compression top dead center (step S25). If it is determined in step S25 that the piston 13 is within the combustion restartable range A, the engine control unit 100 executes an assist combined restart subroutine (step S26). On the other hand, when it is determined that the piston 13 is outside the combustion restartable range A, the engine control unit 100 executes an assist restart subroutine using only the starter 36 (step S27).

  Details of the combustion restart control and the starter combined restart control according to the present embodiment are disclosed in, for example, Japanese Patent Laid-Open No. 2005-2847 and Japanese Patent Laid-Open No. 2005-315197 previously proposed by the applicant. Since what has been applied can be applied as it is, the description thereof will be omitted.

  8 and 9 are flowcharts showing a subroutine of assist restart control according to the present embodiment.

  First, referring to FIG. 8, in the assist restart control, engine control unit 100 first drives starter 36 by the power supply of second battery 80b (that is, in the normal power supply mode) (step S271). Next, the engine control unit 100 determines whether the engine 1 after driving the starter 36 has stalled (step S272). If engine stall occurs, the engine control unit 100 determines whether or not the voltage (sub_vb) of the second battery 80b detected by the second voltage sensor SW2 is equal to or lower than the deterioration determination voltage Vst (step). S273). If the voltage (sub_vb) of the second battery 80b exceeds the deterioration determination voltage Vst, the engine control unit 100 stops driving the starter 36 (step S274) and executes an engine stall process (step S274). Step S275). Here, the “end process” is a warning process that causes the warning notification unit 90 to perform a certain operation. For example, if the warning notification unit 90 is a warning lamp arranged in the instrument panel, they are turned on all at once. If an engine stall occurs even though the supply voltage from the second battery 80b is sufficiently high, the starter 36 may be broken. In this case, the starter 36 is stopped immediately and is wasted. In addition to preventing the operation, the engine stall process is performed to notify the passenger.

  On the other hand, when deterioration of the second battery 80b is recognized in step S273 (YES in step S273), engine control unit 100 attempts to switch the power supply mode from the normal power supply mode to the supplementary power supply mode. Prior to that, it is determined whether or not a decrease in the power supplied to the hill holder 110 can be tolerated.

  Specifically, the engine control unit 100 first determines whether or not the range position of the automatic transmission 2 is a neutral range or a parking range (step S276). If the range position is a neutral range or a parking range, it is considered that it is an operation state that does not need to consider the reverse of the vehicle even if the hill holder 110 is not operating. The power supply mode is switched, and when the range position is outside these ranges, the operation state is further determined.

  If the range position is neither the neutral range nor the parking range, the engine control unit 100 determines whether or not the brake hydraulic pressure Pbk detected by the brake hydraulic pressure sensor 40 is equal to or higher than a predetermined pressure P (δ) (step S278). ). Here, the predetermined pressure P (δ) is a variable corresponding to the road surface gradient δ, and is set to a larger value as the gradient δ increases.

  If the brake hydraulic pressure Pbk detected by the brake hydraulic pressure sensor 40 is less than the pressure P (δ), the engine control unit 100 determines whether or not the road surface gradient δ is within a predetermined angle δs (step S278). . Here, for example, the predetermined angle δs is set in a range of 3 ° to 5 ° so that the vehicle descends backward. If the road surface gradient δ is inclined more than a predetermined angle δs, changing the power supply mode may reduce the braking force by the hill holder 110 and cause the vehicle to move backward. Therefore, in the present embodiment, the buzzer 92 is operated and a warning is issued to the occupant to warn the engine stall and prompt the driver to step on the brake (step S279). In the present embodiment, after the operation control of the buzzer 92, the process returns to the above-described step S276 to determine whether or not the power supply mode can be switched.

  If YES in step S276, step S277, or step S278, the engine control unit 100 stops the operation of the buzzer 92 (if the buzzer 92 is operating) (step S2710) and connects the power relay 85. Thus, the power supply mode is switched to the supplementary power supply mode (step S2711). Next, the engine control unit 100 waits for the engine 1 to complete explosion (step S2712). 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 complete explosion of the engine 1 is detected, the engine control unit 100 executes the blow-up control by retarding the ignition timing after the compression top dead center (step S2713). As a result, it is possible to suppress a rapid increase in the engine speed Ne when the air-fuel mixture is combusted in the stop-time intake stroke cylinder 12C.

  Thereafter, the engine control unit 100 opens the power relay 85 (step S2714), and switches the power supply mode to the normal power supply mode. Thereafter, the operation of the starter 36 is stopped and the process returns to the main routine (step S2715).

  Next, when the engine stall is not recognized in step S272, the engine control unit 100 waits for the engine 1 to complete explosion as shown in FIG. 9 (step S2716). When the complete explosion is not recognized, the engine control unit 100 repeats the processing from step S272 onward. On the other hand, when the complete explosion of the engine 1 is detected, the engine control unit 100 executes the blow-up control (step S2717). Thereafter, the operation of the starter 36 is stopped and the process returns to the main routine (step S2718).

  As described above, in the present embodiment, when the assist condition is satisfied and the starter 36 is driven when the engine 1 is restarted, the deterioration of the second battery 80b is detected. Based on the information, the power supply mode is switched to the supplementary power supply mode only in an operation state in which a decrease in the power supplied to the hill holder 110 is allowed. For this reason, even if the power supplied to the hill holder 110 decreases by switching the power supply mode to the supplementary power supply mode, the vehicle does not move involuntarily.

  Further, in the present embodiment, when the assist condition is satisfied, the second voltage sensor SW2 detects the deterioration of the second battery 80b, and the operation state determination unit 101 reduces the supply power to the hill holder 110. A buzzer 92 is provided as a warning means for issuing a warning to the occupant when prohibited. For this reason, in the present embodiment, when the engine 1 is restarted, the vehicle operation is such that the power supply to the hill holder 110 can be stopped by issuing an alarm to the occupant in an operating situation where the starter 36 cannot sufficiently function due to battery deterioration. (Specifically, depression of the brake pedal, switching of the range position to the parking range, etc.) can be promoted, and the startability of the engine 1 can be improved while preventing the vehicle from involuntarily moving backward.

  Further, in the present embodiment, the reverse information detection means is constituted by either a brake hydraulic pressure sensor 40 that detects an operating hydraulic pressure of a vehicle brake device or an inclination angle sensor 41 that detects a road surface gradient. For this reason, in the present embodiment, the backward information can be detected using the sensors 40 and 41 that are already installed in a normal vehicle, and the power supply mode switching control can be provided with an inexpensive configuration.

  In the present embodiment, the relay control unit 107 as switching means switches the power supply mode to the supplementary power supply mode even when the ignition key switch of the engine 1 is connected. For this reason, in this embodiment, when starting the engine 1 based on a driver | operator's operation, startability can be improved.

  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, in a vehicle equipped with a navigation system, instead of the buzzer 92 described above, a warning such as “please depress the brake pedal” or “shift to the parking range” may be issued to the passenger. . Alternatively, instead of the alarm, the range position of the automatic transmission 2 may be automatically switched to the parking range.

  Further, the “information regarding the reverse of the vehicle” may use an operation signal of a control valve constituting the hill holder 110 and an output of the brake hydraulic pressure sensor 40 instead of the output of the inclination angle sensor or together with the output of the inclination angle sensor. .

  It goes without saying that various modifications can be made 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 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 engine control unit of the vehicle which concerns on this invention. It is a timing chart for demonstrating the deterioration determination of a battery. 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 subroutine of assist restart control which concerns on this embodiment. It is a flowchart which shows the subroutine of assist restart control which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle engine 2 Automatic transmission 30, 31 Crank angle sensor 32 Cam angle sensor 33 Water temperature sensor 34 Accelerator opening sensor 36 Starter 39 Brake booster negative pressure sensor 40 Brake hydraulic pressure sensor 41 Inclination angle sensor 80a First battery 80b Second Battery 82 Vehicle electric load 85 Power relay 87 Charge relay 90 Warning notification unit 92 Buzzer 100 Engine control unit 101 Operating state determination unit 102 Combustion control unit 103 Starter control unit 104 Alternator control unit 105 Power supply state determination unit 106 Electric load control unit 107 Relay control unit (an example of switching means)
108 Warning processing section 109 Buzzer control section 110 Hill holder (an example of an automatic locking brake mechanism)
SW2 Second voltage sensor (an example of battery deterioration detection means)

Claims (4)

When the vehicle is equipped with an automatic locking brake mechanism that restricts involuntary movement at the time of stopping, the engine is automatically stopped when a predetermined automatic stop condition is satisfied, and when a predetermined restart condition is satisfied In a vehicular engine control device that automatically restarts an engine after an automatic stop,
An operation state determination unit for determining an operation state 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 operation state determination unit is satisfied when the restart condition is satisfied;
A first battery for supplying power to an electric load of the vehicle including at least the automatic locking brake mechanism;
A second battery for supplying power to the electric drive device;
Battery deterioration detecting means for detecting at least a deterioration state of the second battery;
By switching the circuit connection between the first and second batteries and the electric drive device, a normal power supply mode for supplying power to the electric drive device from only the second battery, and the first battery together with the second battery. Switching means for switching the power supply mode to the supplementary power supply mode for supplying power to the electric drive device from the battery,
Reverse information detection means for detecting information related to the reverse of the vehicle and outputting the information to the driving state determination unit,
The driving state determination unit has a function of determining whether or not to allow a decrease in power supplied to the automatic lock brake mechanism based on the output of the reverse information detection unit,
When the battery deterioration detection unit detects deterioration of the second battery when the assist condition is satisfied, the switching unit determines whether the driving state determination unit supplies power to the automatic lock brake mechanism. The vehicle engine control apparatus is characterized in that the power supply mode is switched to the supplementary power supply mode only when a decrease is allowed. The vehicle engine control device according to claim 1,
When the assist condition is satisfied, the battery deterioration detection unit detects the deterioration of the second battery, and the driving state determination unit prohibits a decrease in power supplied to the automatic lock brake mechanism. A vehicle engine control device comprising warning means for issuing a warning to an occupant when the vehicle is on. The control device for a vehicle engine according to claim 1 or 2,
The reverse information detection means is constituted by either a brake hydraulic pressure sensor that detects an operating hydraulic pressure of a brake device of the vehicle or an inclination angle sensor that detects a gradient of a road surface. Control device. The control device for a vehicle engine according to any one of claims 1 to 3,
The control device for a vehicle engine, wherein the switching means switches the power supply mode to the supplementary power supply mode even when the ignition key switch of the engine is connected.

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