JP2016022802A - Vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a break actuator with necessary power to stop a vehicle forcibly from a higher speed in the case of failing to start an engine by idling-stop control before stopping the vehicle.SOLUTION: An apparatus includes: a brake actuator capable of driving a brake section independently of brake operation; a first battery capable of supplying a starter with drive power; and a second battery capable of supplying the starter and brake actuator with the drive power. Further, the apparatus performs: stopping an engine in the case of meeting a given engine stop condition, including an event where a vehicular speed is equal to or less than a given permissible speed, when decelerating a vehicle; starting the engine by the starter in the case of meeting a given engine start condition; causing the first battery, of the first and second battery, to supply the starter with the drive power in the case of meeting the given engine start condition before the vehicle is stopped after stopping the engine with the given engine stop condition met when decelerating the vehicle.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a vehicle control device having an idle stop function.

  Conventionally, an idle stop control has been proposed in which the engine is stopped before the vehicle stops when the vehicle decelerates (for example, Patent Document 1).

  In this way, it is possible to improve fuel efficiency by stopping the engine before the vehicle stops, and it is desirable to stop the engine at a higher vehicle speed in order to improve fuel efficiency.

JP 2011-202645 A

  By the way, in order to stop the engine at a higher vehicle speed when the vehicle is decelerated, it is necessary to secure a braking force for appropriately stopping the vehicle.

  More specifically, the vehicle normally amplifies the brake operation force by the negative pressure supplied according to the driving of the engine, drives the hydraulic brake device according to the amplified brake operation force, Generate braking force. Therefore, when the negative pressure is insufficient with the engine stopped, the braking force can be secured by restarting the engine and restarting the supply of the negative pressure.

  On the other hand, if the engine fails to restart, the supply of negative pressure will not be resumed. Therefore, as a fail-safe function, the hydraulic brake device is driven regardless of the brake operation and the brake actuator capable of generating braking force is activated. Let Thereby, even if it is a case where restart of an engine fails, the securing of the braking force for stopping a vehicle can be aimed at. In addition, as a brake actuator, the hydraulic unit of ESC (Electric Stability Control; side slip prevention apparatus) etc. which were comprised so that the wheel cylinder pressure of each wheel could be pressurized independently correspond, for example.

  However, since the brake actuator is driven by a battery, the state of charge of the battery deteriorates due to the supply of power to the starter when the engine restart fails, and if a voltage drop occurs, the brake force that can be generated decreases. . That is, if the remaining capacity of the battery that drives the brake actuator is reduced, it may not be possible to ensure the braking force required to stop the vehicle from a higher vehicle speed.

  Therefore, in view of the above problems, even if the engine start by the idle stop control fails before the vehicle stops, the power necessary for forcibly stopping the vehicle from a higher vehicle speed as a fail-safe function. An object of the present invention is to provide a vehicle control device that can reliably supply the brake actuator to the brake actuator.

In order to achieve the above object, in one embodiment, a vehicle control device includes:
An engine that drives the vehicle;
A starter for starting the engine;
A negative pressure generating unit that generates a negative pressure according to the driving of the engine;
Using the negative pressure supplied from the negative pressure generation unit, a brake booster that amplifies the brake operation force,
A braking unit for generating braking force on the vehicle according to the brake operation force amplified by the brake booster;
A brake actuator configured to be able to drive the braking unit independently of the brake operation;
A first battery configured to supply at least driving power to the starter;
A second battery configured to be able to supply driving power to at least the starter and the brake actuator;
When the vehicle decelerates, the engine is stopped when a predetermined engine stop condition including that the vehicle speed of the vehicle is equal to or lower than a predetermined permitted speed is satisfied, and when the predetermined engine start condition is satisfied, the starter A control unit for starting the engine by
The first battery is satisfied when the predetermined engine stop condition is satisfied during deceleration of the vehicle, and the predetermined engine start condition is satisfied before the vehicle stops after the control unit stops the engine. Among the second batteries, the first battery supplies driving power to the starter.

  According to this embodiment, even if the engine start by the idle stop control fails before the vehicle stops, it is necessary as a fail-safe function to forcibly stop the vehicle from a higher vehicle speed. It is possible to provide a vehicle control device that can reliably supply electric power to a brake actuator.

It is a block diagram which shows an example of a structure of the electric power supply system in the control apparatus for vehicles. It is a block diagram which shows an example of a structure of the control system in the control apparatus for vehicles. It is a schematic block diagram which shows an example of a structure of the brake system in the control apparatus for vehicles. After the engine is stopped at the time of deceleration by the vehicle control device according to the first embodiment, pre-processing when starting the engine before stopping (deceleration-time engine starting pre-processing) and post-processing when the starting fails ( It is a time chart which shows an example of a post-deceleration engine start failure post-processing. It is a flowchart which shows an example of the engine start before deceleration process by the control apparatus for vehicles which concerns on 1st Embodiment, and the process after engine start failure at the time of deceleration. It is a flowchart which shows an example of the engine starting process (engine starting process at the time of deceleration) after the engine stop at the time of the deceleration by the vehicle control apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the method of determining (changing) predetermined capacity | capacitance SOCth. It is a flowchart which shows an example of the engine starting pre-deceleration process at the time of deceleration by the vehicle control apparatus which concerns on 2nd Embodiment, and the process after engine start failure at the time of deceleration. It is a figure which shows an example of the method of determining (changing) the predetermined pressure Pth and the predetermined capacity SOCth.

[First Embodiment]
Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

  1-3 is a figure which shows an example of a structure of the control apparatus 1 for vehicles. FIG. 1 is a block diagram illustrating an example of a configuration of a power supply system in the vehicle control device 1, and FIG. 2 is a block diagram illustrating an example of a configuration of a control system in the vehicle control device 1. FIG. 3 is a schematic configuration diagram illustrating an example of a configuration of a brake system in the vehicle control device 1.

  The vehicle control device 1 includes an engine 10, a starter 11, an alternator 12, a main battery 20, a sub battery 30, an engine ECU 40, an idle stop ECU 50, a brake ECU 60, a brake actuator 70, an auxiliary machine 80, a switching unit 90, and the like. The vehicle control device 1 includes battery sensors 21 and 31, a vehicle speed sensor 92, an MC pressure sensor 94, a negative pressure sensor 96, a front monitoring radar 98, and the like. The vehicle control device 1 includes a vacuum pump 13, a negative pressure pipe 14, a brake booster 15, a brake pedal 16, a master cylinder 17, a wheel cylinder 75, and the like.

  The engine 10 is a driving force source of the vehicle, and is also a negative pressure supply source that drives the vacuum pump 13 and supplies a negative pressure to the brake booster 15 as described later. The engine 10 is started by a starter 11 that is driven by power supply from at least one of the main battery 20 and the sub battery 30. The “starting” includes both starting of the engine 10 by a normal operation of the ignition switch and starting of the engine 10 after the engine 10 is stopped by idle stop control described later.

  The starter 11 is a starting device that starts the engine 10. It is driven by power supply from at least one of the main battery 20 and the sub battery 30.

  The starter relay 11 r is provided in the power supply path from the main battery 20 and the sub battery 30 to the starter 11. The starter relay 11r is controlled by an engine ECU 40, which will be described later, and is switched between connection (ON) and disconnection (OFF). For example, when starting the engine 10, the starter relay 11 r is connected in accordance with a command from the engine ECU 40, and driving power is supplied to the starter 11.

  The alternator 12 is a DC generator that is driven by the power of the engine 10, and includes an AC generator and a rectifier that converts three-phase AC power from the AC generator into DC. The alternator 12 can generate power using the power of the engine 10 transmitted from the crankshaft 10c via the belt 10b. The alternator 12 includes a regulator, and the regulator can control the power generation voltage of the alternator 12 by controlling the power generation control current (the field current flowing through the rotor coil of the alternator 12). The alternator 12 is configured to be able to adjust the amount of power generation by controlling the power generation voltage. The electric power generated by the alternator 12 is charged in the main battery 20 and the sub-battery 30, or supplied as drive power to the engine ECU 40, the idle stop ECU 50, the brake ECU 60, the brake actuator 70, the auxiliary machine 80, and the like.

  The main battery 20 is a power storage device that is connected in parallel to the starter 11, the engine ECU 40, the idle stop ECU 50, the brake ECU 60, the brake actuator 70, the auxiliary machine 80, and the like, and can supply electric power thereto. For example, a lead battery, a nickel metal hydride battery, a lithium ion battery, or the like may be used, and a rated voltage (a voltage across both ends) is about 12V. The main battery 20 is connected to the alternator 12 and can charge the electric power generated by the alternator 12.

  The battery sensor 21 is a known state detection unit that detects the state of the main battery 20 including a state of charge (SOC (State Of Charge)), a deterioration state (SOH (State Of Health)), and the like. For example, it is connected to the negative terminal of the main battery 20. The battery sensor 21 is charged based on, for example, a voltage detection unit, a current detection unit, and a temperature detection unit that detect the voltage, current, and temperature of the main battery 20, and the detected voltage, current, and temperature. In addition, a calculation unit that calculates a deterioration state or the like may be included. The battery sensor 21 is configured to be communicable with the idle stop ECU 50 via an in-vehicle LAN or the like, and information on the state of the main battery 20 including the detected (calculated) state of charge, deterioration state, etc. is transmitted to the idle stop ECU 50.

  Instead of the battery sensor 21, a voltage sensor, a current sensor, a temperature sensor, and the like that detect the voltage, current, temperature, and the like of the main battery 20 may be provided. In this case, each sensor outputs a signal corresponding to the detected voltage, current, temperature, and the like to the idle stop ECU 50, and the idle stop ECU 50 is based on the received signal corresponding to the voltage, current, and temperature. The charging state, the deterioration state, etc. of the main battery 20 are calculated by a known method. Further, a battery state monitoring unit having the same function as the battery sensor 21 may be built in the main battery 20. The same applies to the battery sensor 31 described later.

  Similar to the main battery 20, the sub-battery 30 is a power storage device that is connected in parallel to the starter 11, the engine ECU 40, the idle stop ECU 50, the brake ECU 60, the brake actuator 70, the auxiliary machine 80, and the like and can supply electric power thereto. For example, a lead battery, a nickel metal hydride battery, a lithium ion battery, or the like may be used, and the rated voltage (both ends voltage) is about 12 V, similar to the main battery 20. The sub battery 30 is connected to the alternator 12 and can charge the electric power generated by the alternator 12. The sub-battery 30 is connected to the main battery 20 and the starter 11 (starter relay 11r) via the switching unit 90 (second relay 90b and first relay 90a).

  The sub-battery 30 has a rated voltage different from that of the main battery 20, and is parallel to the starter 11, the engine ECU 40, the idle stop ECU 50, the brake ECU 60, the brake actuator 70, the auxiliary machine 80, and the like via a DC-DC converter or the like. It may be connected. Further, as will be described later, the sub-battery 30 is a brake that pressurizes the wheel cylinder pressure to stop the vehicle as a fail-safe function when the start of the engine 10 by the idle stop control fails before the vehicle stops. Drive power is supplied to the actuator 70. Therefore, the state of the sub-battery 30 needs to be monitored more strictly, and it is desirable to apply a lithium ion battery or the like with a built-in power supply monitoring mechanism.

  The battery sensor 31 is a known state detection unit that detects the state of the sub battery 30 including the state of charge (SOC), the deterioration state (SOH), and the like. The battery sensor 31 is, for example, a voltage detection unit that detects the voltage, current, and temperature of the sub battery 30, a current detection unit, and a temperature detection unit, and a charged state based on the detected voltage, current, and temperature. In addition, a calculation unit that calculates a deterioration state or the like may be included. The battery sensor 31 is configured to be communicable with the idle stop ECU 50 via an in-vehicle LAN or the like, and information regarding the state of the sub battery 30 including the detected (calculated) state of charge, deterioration state, etc. is transmitted to the idle stop ECU 50.

  The engine ECU 40 is an electronic control unit that controls the engine 10, and is operated by electric power supplied from at least one of the alternator 12, the main battery 20, and the sub battery 30. The engine ECU 40 may be constituted by, for example, a microcomputer, and may execute various control processes to be described later by executing various programs stored in the ROM on the CPU.

  For example, the engine ECU 40 determines the fuel injector (fuel injection timing, amount, etc.), spark plug (ignition timing, etc.), intake / exhaust of the engine 10 based on the accelerator opening, vehicle speed, crank angle, cam angle, engine speed, etc. Control valves (open / close timing, etc.).

  Further, the engine ECU 40 controls the power generation amount of the alternator 12 via a regulator in the alternator 12. Specifically, the engine ECU 40 instructs the alternator 12 to generate power, and the regulator in the alternator 12 adjusts the field current according to the generated voltage, whereby the power generation voltage of the alternator 12 is controlled. For example, the engine ECU 40 controls the power generation voltage of the alternator 12 according to the state of charge (SOC) of the main battery 20 and the sub battery 30 detected by the battery sensors 21 and 31. That is, the engine ECU 40 may charge the main battery 20 and the sub-battery 30 by increasing the power generation voltage of the alternator 12 when the state of charge (SOC) of the main battery 20 and the sub-battery 30 falls below a predetermined level. Further, the engine ECU 40 may stop the charging of the main battery 20 and the sub-battery 30 by lowering the power generation voltage of the alternator 12 if the state of charge (SOC) of the main battery 20 and the sub-battery 30 is not less than a predetermined value. .

  Further, the engine ECU 40 controls the starter relay 11 r provided in the power supply path from the main battery 20 and the sub battery 30 to the starter 11 to drive the starter 11 and start the engine 10. For example, when the driver turns on an ignition switch (IG switch), the ON signal is input to the engine ECU 40, and the engine ECU 40 starts the engine 10 by connecting the starter relay 11r.

  Further, the engine ECU 40 receives an engine stop request output from an idle stop ECU 50 described later, and stops the engine 10 by cutting fuel supply in response to the engine stop request. Further, the engine ECU 40 receives the engine start request output from the idle stop ECU 50, drives the starter 11 by controlling the starter relay 11r according to the engine start request, and starts the engine 10. In this way, the engine ECU 40 directly executes engine stop or engine start control in the idle stop function.

  The engine ECU 40 is communicably connected to the engine 10 (within various sensors and actuators), the idle stop ECU 50, the brake ECU 60, and other various sensors via an in-vehicle LAN, a direct line, or the like.

  The idle stop ECU 50 is an electronic control unit that performs idle stop control of the vehicle, and operates by electric power supplied from at least one of the alternator 12, the main battery 20, and the sub battery 30. The idle stop ECU 50 may be constituted by a microcomputer, for example, and may execute various control processes described later by executing various programs stored in the ROM on the CPU. Specifically, it is determined whether or not a predetermined engine stop condition is satisfied. If the engine stop condition is satisfied, an engine stop request is output to the engine ECU 40. For example, while the vehicle is running, the master cylinder pressure (hereinafter referred to as the MC pressure) is greater than or equal to a predetermined depression pressure at every predetermined time (the brake is depressed more than a predetermined amount), and the vehicle speed of the vehicle It is determined whether or not a predetermined engine stop condition is satisfied, including that the engine speed falls below a predetermined permitted speed. As described above, when the vehicle speed of the vehicle drops below a predetermined permitted speed during deceleration (when the MC pressure is equal to or higher than the predetermined depression pressure), the idle stop ECU 50 turns off the engine ECU 40 before the vehicle stops. Thus, the engine 10 can be stopped. Thereby, a fuel consumption improvement can be aimed at.

  Further, the idle stop ECU 50 determines whether or not a predetermined engine start condition is satisfied, and outputs an engine start request to the engine ECU 40 when the engine start condition is satisfied. For example, whether or not the engine start condition is satisfied, including that the MC pressure is equal to or lower than the predetermined release pressure (the brake depression is released) at every predetermined time while the engine 10 is stopped by the idle stop control. Determine.

  The engine stop condition and the engine start condition include, for example, the rotational speed of the engine 10, the cooling water temperature, the state of the main battery 20 (current, voltage, temperature, charge state, deterioration state) in addition to the above-described conditions related to the vehicle speed and MC pressure Etc.), conditions regarding negative pressure of the brake booster 15, door courtesy switch (not shown), and the like. For example, the engine stop condition may include a condition that the state of charge (SOC) of the main battery 20 detected (calculated) by the battery sensor 21 is a predetermined value or more. Further, the engine start condition may include a condition that the negative pressure of the brake booster 15 is reduced to a predetermined threshold value or less.

  Further, the idle stop ECU 50 performs control to switch connection (ON) and disconnection (OFF) of the first relay 90 a and the second relay 90 b included in the switching unit 90. Specifically, the path for supplying power from the sub-battery 30 to the starter 11 is blocked by blocking one of the first relay 90a and the second relay 90b that are normally connected. Details of the control process will be described later.

  Further, the idle stop ECU 50 provides the fail-safe function when the engine 10 fails to start when the engine start condition is satisfied before the vehicle stops, via the brake ECU 60 regardless of the brake operation. To generate a braking force. Specifically, the brake ECU 60 executes pressurization control (control to increase the hydraulic pressure of the wheel cylinder 75 (wheel cylinder pressure) and generate braking force on the vehicle regardless of the brake operation), which will be described later. Outputs pressurization control request. Thus, even if the braking force is forcibly generated, the engine 10 fails to start, the negative pressure is not supplied from the vacuum pump 13 to the brake booster 15, and the braking force corresponding to the brake operation becomes insufficient. The vehicle can be stopped. In response to the pressurization control request, a pressurization control release request for stopping the pressurization control by the brake ECU 60 is output. Details of the control process will be described later.

  The idle stop ECU 50 includes battery sensors 21, 31, engine ECU 40, brake ECU 60, switching unit 90, vehicle speed sensor 92, MC pressure sensor 94, negative pressure sensor 96, forward monitoring radar 98, etc. Communicatively connected.

  The brake ECU 60 is an electronic control unit that performs braking control of the vehicle. For example, the brake ECU 60 controls the brake actuator 70 that operates a hydraulic brake device including a wheel cylinder 75 disposed on each wheel. Further, the brake ECU 60 is operated by electric power supplied from at least one of the alternator 12, the main battery 20, and the sub battery 30. The brake ECU 60 may be configured by a microcomputer, for example, and may execute various control processes described later by executing various programs stored in the ROM on the CPU. Specifically, by supplying MC pressure to the wheel cylinder 75 via the brake actuator 70, control is performed to operate the hydraulic brake device (wheel cylinder 75) in accordance with the brake operation (normal control). Further, the brake actuator 70 is controlled to pressurize or depressurize the oil pressure (wheel cylinder pressure) of the wheel cylinder 75 to operate the hydraulic brake device (wheel cylinder 75) irrespective of the brake operation (pressure control). , Decompression control). The brake ECU 60 is communicably connected to the brake actuator 70 or the like via an in-vehicle LAN or a direct line.

  Note that the functions of the engine ECU 40, the idle stop ECU 50, and the brake ECU 60 described above may be realized by arbitrary hardware, software, firmware, or a combination thereof. Further, some or all of the functions of the engine ECU 40, the idle stop ECU 50, and the brake ECU 60 may be realized by another ECU. Further, the engine ECU 40, the idle stop ECU 50, and the brake ECU 60 may realize part or all of the functions of other ECUs. For example, some or all of the functions of the idle stop ECU 50 may be realized by the engine ECU 40, and some or all of the functions of the idle stop ECU 50 may be realized by the brake ECU 60.

  The brake actuator 70 is a braking means that generates a braking force on the vehicle by operating a hydraulic brake device (wheel cylinder 75). The brake actuator 70 includes at least one of the alternator 12, the main battery 20, and the sub battery 30. Operates with supplied power. The brake actuator 70 is configured to be able to operate a hydraulic brake device (wheel cylinder 75) disposed on each wheel in accordance with a brake operation (brake operation force, operation amount). The brake actuator 70 is configured to be able to operate a hydraulic brake device (wheel cylinder 75) regardless of the brake operation (brake operation force, operation amount).

  As shown in FIG. 3, in the vehicle brake system, the brake operating force from the brake pedal 16 is amplified by the brake booster 15 and acts as MC pressure (hydraulic pressure) in the master cylinder 17. The MC pressure is supplied to the brake actuator 70 through the oil lines OL1 and OL2, and the brake actuator 70 holds, pressurizes, or depressurizes the MC pressure in accordance with a command from the brake ECU 60. The brake actuator 70 operates the hydraulic brake device by supplying the MC pressure (hydraulic pressure) that has been held, pressurized, or reduced to the wheel cylinders 75a to 75d of the wheels through the oil lines OLa to OLd. . That is, the brake actuator 70 can operate the wheel cylinders 75a to 75d in accordance with the brake operation by holding the MC pressure and supplying it to the wheel cylinders 75a to 75d of the respective wheels. Further, the brake actuator 70 can operate the wheel cylinders 75a to 75d independently of the brake operation by increasing and decreasing the MC pressure and supplying them to the wheel cylinders 75a to 75d of the respective wheels.

  The brake booster 15 amplifies the brake operation force by using the negative pressure generated by the vacuum pump 13 driven by the cam of the engine 10 and supplied through the negative pressure pipe 14. However, as the negative pressure supplied to the brake booster 15, intake pressure (negative pressure) generated in the intake manifold due to the pumping loss of the engine 10 may be used. Further, the “negative pressure” in the present embodiment is a pressure lower than the atmospheric pressure and means a differential pressure from the atmospheric pressure. Therefore, when the negative pressure increases, the absolute pressure decreases, and when the negative pressure decreases, the absolute pressure increases and approaches atmospheric pressure.

  The brake actuator 70 may be configured to be able to pressurize, hold, or reduce the MC pressure regardless of the operation of the brake pedal 16, and includes a pump that generates high pressure oil, a motor that drives the pump, and various valves (hydraulic pressure). A holding valve for holding the pressure, a pressure reducing valve for reducing the pressure, etc.), a hydraulic circuit and the like. For example, a hydraulic unit used in an ESC (Electric Stability Control) may be used.

  The auxiliary machine 80 is an electric load that operates by supplying power from at least one of the alternator 12, the main battery 20, or the sub-battery 30, and includes a first auxiliary machine 80a and a second auxiliary machine 80b.

  The first auxiliary machine 80a is an electrical load that can tolerate a relatively large voltage drop when, for example, the starter 11 is driven by the main battery 20 and the sub battery 30, for example, a headlight, a wiper, an air conditioner, a meter, etc. The electrical component may be included.

  The second auxiliary machine 80b is an electric load that is hindered by a relatively large voltage drop, that is, cannot accept a relatively large voltage drop, and may include audio, car navigation, various ECUs other than those described above, and the like. . Note that audio and car navigation systems prevent system reset due to voltage drop (sound suddenly stops or screen disappears), and various ECUs cannot tolerate voltage drop to prevent malfunction due to voltage drop.

  The switching unit 90 is a means for switching between connection and disconnection of a path for supplying power from the sub battery 30 to the starter 11, and includes a first relay 90a and a second relay 90b. The switching unit 90 is controlled by the idle stop ECU 50, and shuts off (OFF) one of the first relay 90a and the second relay 90b, thereby shutting off the path for supplying power from the sub battery 30 to the starter 11. Can do.

  The first relay 90a is configured to be able to switch connection and disconnection between the parallel-connected main battery 20, the starter 11, the alternator 12, and the like, and the parallel-connected engine ECU 40, the second auxiliary device 80b, and the like.

  The second relay 90b can switch between connection and disconnection of the engine ECU 40, the second auxiliary machine 80b, etc. connected in parallel with the sub battery 30, the idle stop ECU 50, the brake ECU 60, the brake actuator 70, etc. connected in parallel. Configured.

  That is, when the first relay 90a is cut off (OFF) and the second relay 90b is connected (ON), the main battery 20 supplies power to the starter 11, the first auxiliary machine 80a, and the like. On the other hand, the sub-battery 30 supplies power to the engine ECU 40, the idle stop ECU 50, the brake ECU 60, the brake actuator 70, the second auxiliary machine 80b, and the like, and does not supply power to the starter 11. In this case, the engine ECU 40, the idle stop ECU 50, the brake ECU 60, and the second auxiliary machine 80b are disconnected from the main battery 20, and therefore may be affected by the voltage drop of the main battery 20 when the starter 11 is driven. Disappear.

  When the first relay 90a is connected (ON) and the second relay 90b is cut off (OFF), the main battery 20 includes the starter 11, the first auxiliary machine 80a, the engine ECU 40, and the second auxiliary machine 80b. Supply power to etc. On the other hand, the sub-battery 30 supplies power to the idle stop ECU 50, the brake ECU 60, the brake actuator 70, and the like, and does not supply power to the starter 11. In this case, the target of power supply by the sub-battery 30 is limited to the idle stop ECU 50, the brake ECU 60, the brake actuator 70, and the like related to the operation of the brake system. Therefore, the power supply from the sub battery 30 can be concentrated on the operation of the brake system.

  In any case, since the sub-battery 30 does not supply power to the starter 11, even when the engine 10 is started, power is not consumed and the remaining capacity can be secured (maintained).

  The vehicle speed sensor 92 is known detection means for detecting the vehicle speed of the vehicle. The vehicle speed sensor 92 is configured to be communicable with the idle stop ECU 50 via an in-vehicle LAN or the like, and a signal (vehicle speed signal) corresponding to the detected vehicle speed is transmitted to the idle stop ECU 50.

  The MC pressure sensor 94 is a known detection means for detecting the MC pressure in the master cylinder 17. The MC pressure sensor 94 is configured to be able to communicate with the idle stop ECU 50 via an in-vehicle LAN or the like, and a signal (MC pressure signal) corresponding to the detected MC pressure is transmitted to the idle stop ECU 50.

  The negative pressure sensor 96 is known detection means for detecting a negative pressure in the brake booster 15 (a negative pressure chamber thereof). A signal (negative pressure signal) corresponding to the detected negative pressure is transmitted to the idle stop ECU 50.

  The front monitoring radar 98 is an obstacle detection unit that detects an obstacle ahead of the vehicle and can detect (calculate) a distance from the vehicle to the detected obstacle. The forward monitoring radar 98 may be, for example, an ultrasonic radar, a millimeter wave radar, a laser radar, a UWB (Ultra Wide Band) radar, or the like. The front monitoring radar 98 is configured to be communicable with the idle stop ECU 50 via an in-vehicle LAN or the like, and obstacle information including a distance to the detected obstacle is transmitted to the idle stop ECU 50.

  Instead of the front monitoring radar 98, a stereo camera or the like that images the front of the vehicle may be provided. In this case, for example, the image processing unit inside the stereo camera, the idle stop ECU 50, or the like may detect an obstacle ahead of the vehicle and calculate the distance to the obstacle based on the image captured by the stereo camera.

  Next, after the engine 10 is stopped at the time of deceleration by the vehicle control device 1 according to the present embodiment, the pre-processing when the engine 10 is started before the vehicle stops (pre-deceleration engine starting pre-processing), and the start fails The post-processing (processing after engine start failure during deceleration) will be described.

  FIG. 4 is a time chart illustrating an example of pre-deceleration engine start processing and post-deceleration engine start failure processing by the vehicle control apparatus 1 according to the present embodiment. FIG. 4 shows (a) brake operation, (b) vehicle speed, (c) main battery 20 voltage, (d) engine 10 rotation speed, (e) engine 10 state, (f) brake system over time. The state (g) shows the change of the power supply source to the brake actuator 70.

  Until the time t1, the vehicle is traveling at a substantially constant vehicle speed according to the driving of the engine 10. Further, since the negative pressure is generated by the vacuum pump 13 in accordance with the driving of the engine 10, the brake system is in a state where the negative pressure is supplied to the brake booster 15. In general, the first relay 90 a and the second relay 90 b are connected (ON), and the brake actuator 70 is operable by supplying power from both the main battery 20 and the sub battery 30.

  When the driver starts the brake operation (depresses the brake pedal 16) at time t1, the vehicle starts to decelerate and the vehicle speed starts to decrease. Then, at time t2, a predetermined permitted speed Vis that is a threshold value within a condition relating to the vehicle speed included in the engine stop condition described above (the vehicle speed is equal to or lower than the predetermined permitted speed) is reached.

  When all engine stop conditions including conditions related to vehicle speed are satisfied at time t2, engine ECU 40 stops engine 10 in response to an engine stop request from idle stop ECU 50. That is, the engine 10 stops during deceleration of the vehicle. Since the vacuum pump 13 does not operate when the engine 10 is stopped, the brake system is in a state where the negative pressure supply to the brake booster 15 is stopped.

  The driver continues the brake operation after time t2, and the vehicle decelerates. However, when the driver stops the brake operation at time t3 (releases the depression of the brake pedal 16), the engine start condition is satisfied before the vehicle stops, and the idle stop ECU 50 issues an engine start request to the engine ECU 40. Output. The engine ECU 40 starts the engine 10 by driving the starter 11 in response to an engine start request from the idle stop ECU 50. At the same time, the idle stop ECU 50 transmits a command to the switching unit 90 to block the path for supplying power from the sub battery 30 to the starter 11. That is, the brake actuator 70 becomes operable by supplying power from the sub battery 30. The “deceleration engine start pre-processing” described above mainly refers to a process in which the idle stop ECU 50 cuts off the path for supplying power from the sub battery 30 to the starter 11 (via the switching unit 90).

  The starter 11 starts the engine 10 from the time t3 to the time t4, but the engine 10 does not increase to the startable speed, and the engine 10 fails to start at the time t4. Then, the idle stop ECU 50 outputs a pressurization control request to the brake ECU 60, and the brake ECU 60 generates a braking force on the vehicle via the brake actuator 70 regardless of the brake operation by the driver. That is, the brake system of the vehicle is in a state where the wheel cylinder pressure is increased regardless of the brake operation by the driver. At this time, the brake actuator 70 is driven by electric power from the sub battery 30. The above-described “deceleration engine start failure post-processing” described above mainly causes the idle stop ECU 50 to increase the wheel cylinder pressure via the brake ECU 60 and to generate braking force on the vehicle regardless of the brake operation by the driver. Refers to processing.

  Note that, since time t4 when the engine 10 has failed to start, the driver has stepped on the brake pedal 16 in an attempt to stop the vehicle. However, since the negative pressure is not supplied from the vacuum pump 13, the negative pressure decreases. That is, even if hydraulic pressure is generated in the wheel cylinder 75 according to the brake operation, only a braking force smaller than usual is generated.

  The pressurization control by the brake ECU 60 is performed from time t4, so that the vehicle decelerates, and the vehicle stops (the vehicle speed becomes 0) at time t5.

  After time t5, pressurization control by the brake ECU 60 continues, and at time t6, the idle stop ECU 50 outputs a pressurization control release request to the brake ECU 60 with the vehicle surely stopped. Pressure control is stopped. In addition, the idle stop ECU 50 transmits a command to the switching unit 90 and connects a path for supplying power from the sub battery 30 to the starter 11. That is, the brake actuator 70 returns to an operable state by supplying power from both the main battery 20 and the sub battery 30.

  As described above, the vehicle control apparatus 1 (idle stop ECU 50) according to the present embodiment satisfies the engine stop condition when the vehicle is decelerated, and sets the engine start condition before the vehicle stops after the engine 10 stops. When satisfied, when the engine 10 is started, the switching unit 90 cuts off the path for supplying power from the sub battery 30 to the starter 11. That is, when the engine 10 is started when the vehicle is decelerated, the starter 11 is driven by the electric power from the main battery 20 out of the main battery 20 and the sub battery 30. Thereby, when the engine 10 is started, power is not supplied from the sub battery 30 to the starter 11, so that the remaining capacity of the sub battery 30 is maintained.

  In addition, the vehicle control device 1 (idle stop ECU 50) starts the engine 10 after the engine 10 is stopped when the vehicle is decelerated. If the start fails, the vehicle control device 1 (idle stop ECU 50) controls the wheel actuator 70 via the brake ECU 60 to the wheel cylinder 70. Pressurize the pressure. That is, the hydraulic braking device (wheel cylinder 75) is operated to generate a braking force regardless of the brake operation. As a result, even when the engine 10 has failed to start before the vehicle stops (that is, during traveling), the negative pressure supply from the vacuum pump 13 that operates according to the driving of the engine 10 is stopped. The vehicle can be stopped by generating a desired braking force.

  Further, since the remaining capacity of the sub-battery 30 that supplies driving power to the brake actuator 70 is maintained, even if the vehicle speed at the time when the engine 10 fails to start is high, the vehicle is stopped. A braking force can be generated appropriately. That is, even if the start of the engine 10 by the idle stop control fails before the vehicle stops, the electric power necessary to forcibly stop the vehicle from a higher vehicle speed is provided as a fail-safe function. The brake actuator 70 can be reliably supplied. Therefore, the fuel consumption can be improved by stopping the engine 10 by idle stop control at a higher vehicle speed. That is, it is possible to achieve both engine stop (improvement of fuel efficiency) by idle stop control at a higher vehicle speed during vehicle deceleration and securing of braking force for appropriately stopping the vehicle after engine stop.

  FIG. 5 is a flowchart illustrating an example of pre-deceleration engine start processing and post-deceleration engine start failure processing by the vehicle control apparatus 1 (idle stop ECU 50) according to the present embodiment, and corresponds to the time chart shown in FIG. To do. The flowchart is executed when the engine stop condition is satisfied when the vehicle is decelerated and the engine start condition is satisfied after the engine 10 stops and before the vehicle stops.

  In step S101, the first relay 90a is disconnected (switched from ON to OFF), and the second relay 90b remains in the connected (ON) state. That is, by cutting off the first relay 90a, the path for supplying power from the sub battery 30 to the starter 11 is cut off.

  In step S102, it is determined whether or not a starting failure has occurred, that is, whether or not the engine 10 has failed to start. If the engine 10 has failed to start, the process proceeds to step S103. If the engine 10 has not failed to start, that is, if the engine has been successfully started, the process proceeds to step S109.

  In step S103, based on the vehicle speed signal from the vehicle speed sensor 92, it is determined whether or not the vehicle speed of the vehicle is equal to or higher than a predetermined speed Vth. When the vehicle speed of the vehicle is equal to or higher than the predetermined speed Vth, the process proceeds to step S104, and when lower than the predetermined speed Vth, the process proceeds to step S109.

  The predetermined speed Vth is set within a range equal to or less than the vehicle speed at which the stop of the engine 10 is permitted by the idle stop control (the above-described predetermined permission speed Vis). The predetermined speed Vth is set as a vehicle speed at which the vehicle cannot be stopped within a predetermined distance by a braking force generated in response to a brake operation in a state where the negative pressure supply from the vacuum pump 13 is stopped, for example. May be. In other words, the predetermined speed Vth is a vehicle speed at which the idle stop ECU 50 starts intervention in order to generate a braking force for stopping the vehicle.

  In step S104, the first relay 90a is switched from cutoff (OFF) to connection (ON), and the second relay 90b is switched from connection (ON) to cutoff (OFF).

  In step S105, a pressurization control request is output to the brake ECU 60. That is, the wheel cylinder pressure is increased by the brake actuator 70 via the brake ECU 60 regardless of the brake operation.

  In step S106, based on the vehicle speed signal from the vehicle speed sensor 92, it is determined whether or not the vehicle has stopped (whether or not the vehicle speed has become zero). If the vehicle has stopped, the process proceeds to step S107. If the vehicle has not stopped, the determination is repeated until the vehicle stops.

  In step S107, it is determined whether or not a predetermined time T has elapsed. If the predetermined time T has elapsed, the process proceeds to step S108. If the predetermined time T has not elapsed, the determination is repeated until the predetermined time T elapses.

  In step S108, a pressurization control cancellation request is output to the brake ECU 60. That is, the pressurization of the wheel cylinder pressure by the brake actuator 70 is stopped.

  In step S109, the first relay 90a and the second relay 90b are both returned to the connected (ON) state, and the current process is terminated.

  Thus, the vehicle control apparatus 1 (idle stop ECU 50) according to the present embodiment starts the engine 10 after the engine 10 is stopped by the idle stop control during deceleration of the vehicle and before the vehicle stops. The first relay 90a is shut off. As a result, engine ECU 40, idle stop ECU 50, brake ECU 60, and second auxiliary machine 80b are disconnected from main battery 20, so that they are not affected by the voltage drop of main battery 20 when engine 10 is started. can do. Therefore, it is not necessary to provide a BBC (Backup Boost Converter) or a DC-DC converter in order to boost the voltage of the main battery 20 that decreases when the engine 10 is started.

  In addition, when the engine start condition is satisfied and the engine 10 is started when the vehicle is stopped, the first relay 90a may be cut off similarly (while the second relay 90b is connected). Similarly, when the driver's IG-ON operation is performed from the ACC-ON state (when the engine 10 is started by the driver's IG-ON operation), the second relay 90b remains connected. )) The first relay 90a may be cut off. In these cases, the same actions and effects as described above can be obtained.

  Further, the vehicle control device 1 (idle stop ECU 50) cuts off the second relay 90b when the brake actuator 70 is pressurized with the wheel cylinder pressure. As a result, the power supply target of the sub battery 30 is limited to the components related to the pressurization (idle stop ECU 50, brake ECU 60, brake actuator 70), so the remaining capacity of the sub battery 30 is used for the pressurization. It can be used intensively. That is, even if the start of the engine 10 by the idle stop control fails before the vehicle stops, the electric power necessary to forcibly stop the vehicle from a higher vehicle speed is provided as a fail-safe function. The brake actuator 70 can be supplied more reliably.

  Further, the vehicle control device 1 (idle stop ECU 50) determines that the brake actuator is activated when the engine 10 fails to start by the idle stop control before the vehicle stops and the vehicle speed of the vehicle is equal to or higher than the predetermined speed Vth. The wheel cylinder pressure is increased to 70. That is, the wheel cylinder 75 is driven to generate a braking force on the vehicle regardless of the brake operation. Accordingly, the braking force is generated in the vehicle by the intervention when there is a possibility that the vehicle cannot be stopped properly by the braking force generated according to the brake operation in a state where the negative pressure supply from the vacuum pump 13 is stopped. (When the vehicle speed is relatively high). Therefore, it is possible to reduce the uncomfortable feeling given to the driver by generating braking force on the vehicle by intervention. In other words, before the vehicle stops, while ensuring a fail-safe function in the case where the engine 10 fails to start by idle stop control, a sense of discomfort given to the driver by the fail-safe function (generation of braking force by intervention) is reduced. Can be planned.

  If the fail-safe function is prioritized and the vehicle is not stopped, the engine 10 is not started by the idle stop control regardless of the vehicle speed (even if the vehicle speed is lower than the predetermined speed Vth). The wheel cylinder pressure may be applied to the actuator 70.

  Next, the engine 10 start process (deceleration engine start process) after the engine 10 is stopped during deceleration by the vehicle control apparatus 1 according to the present embodiment will be described. The deceleration engine start process is a control process based on the premise that the deceleration engine start pre-process and the deceleration engine start failure process shown in FIGS.

  FIG. 6 is a flowchart showing an example of engine start processing during deceleration by the vehicle control device 1 (idle stop ECU 50) according to the present embodiment. The flowchart is executed at predetermined time intervals between the time when the vehicle is decelerated and the engine stop condition is satisfied and the engine 10 is stopped until the engine start condition is satisfied.

  In step S201, based on the vehicle speed signal from the vehicle speed sensor 92, it is determined whether or not the vehicle speed of the vehicle is equal to or higher than a predetermined speed Vth. If the vehicle speed of the vehicle is equal to or higher than the predetermined speed Vth, the process proceeds to step S202. If the vehicle speed of the vehicle is lower than the predetermined speed Vth, the current process is terminated.

  In step S202, based on the information from the battery sensor 31, it is determined whether the remaining capacity of the sub battery 30 is lower than a predetermined capacity SOCth. If the remaining capacity of the sub-battery 30 is lower than the predetermined capacity SOCth, the process proceeds to step S203. If the remaining capacity of the sub-battery 30 is greater than or equal to the predetermined capacity SOCth, the current process is terminated.

  The predetermined capacity SOCth is the remaining capacity of the sub-battery 30 necessary for generating a braking force for appropriately stopping the vehicle before stopping (during traveling) by pressurization of the wheel cylinder pressure by the brake actuator 70 described above. A value obtained by adding a predetermined margin may be set.

  In step S203, an engine start request is output to the engine ECU 40, the engine 10 is started, and the current process is terminated.

  As described above, the vehicle control apparatus 1 (idle stop ECU 50) according to the present embodiment satisfies the engine stop condition when the vehicle is decelerated, and the vehicle speed of the vehicle is the predetermined speed Vth while the engine 10 is stopped. When the remaining capacity of the sub-battery 30 is lower than the predetermined capacity SOCth, the engine 10 is started. That is, when it is difficult to perform the post-deceleration engine start failure post-deceleration process (a process of increasing the wheel cylinder pressure regardless of the brake operation) with a predetermined margin or more, the engine 10 is started. Thereby, the said vehicle can be stopped appropriately according to a driver | operator's brake operation using the negative pressure supplied from the vacuum pump 13. FIG. Further, the engine 10 is started when there is a possibility that the vehicle cannot be stopped properly by the braking force generated in response to the brake operation in a state where the negative pressure supply from the vacuum pump 13 is stopped (the vehicle speed is relatively high). (If it is expensive). Therefore, the uncomfortable feeling given to the driver can be reduced by starting the engine 10 before the vehicle stops.

  Even if the vehicle control device 1 fails to start, the vehicle control device 1 appropriately controls the vehicle by the post-deceleration engine start failure processing described above (processing for increasing the wheel cylinder pressure regardless of the brake operation). It can be stopped. This is because the predetermined capacity SOCth is a value obtained by adding a predetermined margin to the remaining capacity of the sub-battery 30 necessary for generating a braking force to appropriately stop the vehicle before stopping (during traveling). In addition, giving priority to stopping the vehicle with a margin, if the vehicle is not stopped, the remaining capacity of the sub-battery 30 is maintained regardless of the vehicle speed (even if the vehicle speed is lower than the predetermined speed Vth). If it is lower than the predetermined capacity SOCth, the engine 10 may be started.

  Further, the predetermined capacity SOCth need not be a constant value. In other words, the remaining capacity of the sub-battery 30 necessary for generating a braking force to appropriately stop the vehicle before stopping (running) varies depending on the vehicle speed, so that it can be changed according to the vehicle speed. Also good. For example, when the predetermined capacity SOCth is set to a constant value, it is necessary to determine the predetermined capacity SOCth on the assumption that the vehicle is stopped from a predetermined permission speed Vis. Therefore, by changing according to the vehicle speed, when the vehicle speed is relatively low, the uncomfortable feeling given to the driver by starting the engine 10 can be reduced.

  FIG. 7 is a diagram illustrating an example of a method for determining (changing) the predetermined capacity SOCth. Specifically, the vehicle speed range of the vehicle is an upper table, and a predetermined capacity SOCth corresponding to each vehicle speed range is a lower table.

  This example shows an example when the sub battery 30 is a lithium ion battery, a nickel metal hydride battery, or the like (in the case of a power storage device that can drive the brake actuator 70 even if the SOC is 50% or less). In addition, the interrelationship among the speeds V1, V2, V3, V4, the predetermined permitted speed Vis, and the predetermined speed Vth in the figure is Vis> V1> V2> V3> V4 = Vth. Further, the predetermined capacity SOCth is displayed as a ratio (charge rate) to full charge.

  Referring to FIG. 7, when vehicle speed Vs is V1 ≦ Vs ≦ Vis, predetermined capacity SOCth is set to 35%. When vehicle speed Vs is V2 ≦ Vs <V1, predetermined capacity SOCth is set to 30%. When vehicle speed Vs is V3 ≦ Vs <V2, predetermined capacity SOCth is set to 25%. When vehicle speed Vs is V4 ≦ Vs <V3, predetermined capacity SOCth is set to 20%.

  Thus, the predetermined capacity SOCth may be set to increase as the vehicle speed of the vehicle increases.

  In this example, the predetermined capacity SOCth is set to change stepwise with respect to the change in the vehicle speed of the vehicle. However, it may be set to change continuously at least in part.

  Further, the predetermined capacity SOCth may be changed in accordance with the distance from an obstacle (such as a preceding vehicle) in front of the vehicle detected by the front monitoring radar 98. That is, when there is an obstacle in front of the vehicle, it is necessary to stop the vehicle before colliding with the obstacle. Therefore, as the distance from the detected obstacle becomes shorter, a larger braking force is generated. There is a need. Therefore, the predetermined capacity SOCth may be set to increase as the distance from the obstacle ahead of the vehicle detected by the front monitoring radar 98 decreases.

[Second Embodiment]
Next, a second embodiment will be described.

  The vehicle control apparatus 1 according to the present embodiment is the first embodiment in that when the predetermined condition is satisfied before the post-deceleration engine start failure processing described above is satisfied, the engine 10 is started again. And different. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and different portions will be mainly described.

  Since the configuration of the vehicle control device 1 according to the present embodiment is represented in FIGS. 1 to 3 as in the first embodiment, the description thereof is omitted.

  FIG. 8 is a flowchart showing an example of pre-deceleration engine start processing and post-deceleration engine start failure processing by the vehicle control apparatus 1 according to the present embodiment. The flowchart is executed when the engine stop condition is satisfied when the vehicle is decelerated and the engine start condition is satisfied after the engine 10 stops and before the vehicle stops.

  In step S301, as in step S101, the first relay 90a is disconnected (switched from ON to OFF), and the second relay 90b remains in the connected (ON) state. That is, by cutting off the first relay 90a, the path for supplying power from the sub battery 30 to the starter 11 is cut off.

  In step S302, the deterioration state (SOH) of the main battery 20 is detected based on information from the battery sensor 21 (information on the deterioration state of the main battery 20 detected when the engine 10 is started).

  As described above, the idle stop ECU 50 may calculate the deterioration state (SOH) of the main battery 20 by itself based on the current, voltage, temperature, and the like of the main battery 20. For example, since there is a known relationship between the minimum value of the voltage of the main battery 20 at the time of starting the engine 10 and the deterioration state (SOH), the deterioration state of the main battery 20 (based on the relationship (map)) ( SOH) may be calculated.

  In step S303, as in step S102, it is determined whether or not a starting failure has occurred, that is, whether or not the engine 10 has failed to start. If the engine 10 has failed to start, the process proceeds to step S304. If the engine 10 has not failed to start, that is, if the engine has been successfully started, the process proceeds to step S314.

  In step S304, as in step S103, based on the vehicle speed signal from the vehicle speed sensor 92, it is determined whether or not the vehicle speed of the vehicle is equal to or higher than a predetermined speed Vth. When the vehicle speed of the vehicle is equal to or higher than the predetermined speed Vth, the process proceeds to step S305, and when lower than the predetermined speed Vth, the process proceeds to step S314. The predetermined speed Vth is the same as that in the first embodiment.

  In step S305, based on the deterioration state (SOH) of the main battery 20 detected in step S302, it is determined whether or not the cause of the start failure of the engine 10 is due to deterioration of the main battery 20. When the cause of the start failure of the engine 10 is the deterioration of the main battery 20, the process proceeds to step S309, and when the cause of the start failure of the engine 10 is not the main battery 20, the process proceeds to step S306.

  It should be noted that the idle stop ECU 50 may determine “deterioration” of the main battery 20 when the detected deterioration state (SOH) of the main battery 20 has decreased to a predetermined value or less.

  In step S306, based on the negative pressure signal from the negative pressure sensor 96 and the information from the battery sensor 31, the negative pressure of the brake booster 15 is lower than the predetermined pressure Pth, or the remaining capacity of the sub battery 30 is the predetermined capacity SOCth. Determine if any of the lower is satisfied. When the negative pressure of the brake booster 15 is lower than the predetermined pressure Pth, or when the remaining capacity of the sub-battery 30 is lower than the predetermined capacity SOCth, the process proceeds to step S309, and the negative pressure of the brake booster 15 is equal to or higher than the predetermined pressure Pth. If the remaining capacity of the sub-battery 30 is equal to or greater than the predetermined capacity SOCth, the process proceeds to step S307.

  Note that the predetermined pressure Pth is equal to the negative pressure of the brake booster 15 required to generate a braking force for properly stopping the vehicle before stopping (during traveling) according to the driver's braking operation. May be set as a value obtained by adding In addition, the predetermined capacity SOCth is used to generate a braking force for appropriately stopping the vehicle before stopping (during traveling) by pressurizing the wheel cylinder pressure by the brake actuator 70, as in the first embodiment (FIG. 6). May be set as a value obtained by adding a predetermined margin to the remaining capacity of the sub-battery 30 required.

  In this step, whether or not the remaining capacity of the sub-battery 30 is lower than the predetermined capacity SOCth is considered only when the braking force is generated regardless of the driver's braking operation by the intervention and the vehicle is stopped. It may be determined. In this case, when it is lower than the predetermined capacity SOCth, the process proceeds to step S309, and when it is equal to or greater than the predetermined capacity SOCth, the process proceeds to step S307.

  In step S307, it is determined whether the number of restarts in step S308 described later is less than the predetermined number Nth. When the number of restarts is less than the predetermined number Nth, the process proceeds to step S308, and when the number is greater than the predetermined number Nth, the process proceeds to step S309. Note that the predetermined number Nth may be set to, for example, twice. That is, the number of attempts to restart the engine 10 may be one.

  In step S308, the engine ECU 40 outputs a start request, attempts to restart the engine 10, and returns to step S302. In the flowchart, the start of the engine 10 in this step is referred to as “restart”.

  In step S309, as in step S104, the first relay 90a is switched from cutoff (OFF) to connection (ON), and the second relay 90b is switched from connection (ON) to cutoff (OFF).

  In step S310, as in step S105, a pressure control request is output to the brake ECU 60. That is, the wheel cylinder pressure is increased by the brake actuator 70 via the brake ECU 60 regardless of the brake operation.

  In step S311, as in step S106, based on the vehicle speed signal from the vehicle speed sensor 92, it is determined whether or not the vehicle has stopped (whether or not the vehicle speed has become 0). If the vehicle has stopped, the process proceeds to step S310. If the vehicle has not stopped, the determination is repeated until the vehicle stops.

  In step S312, as in step S107, it is determined whether or not a predetermined time T has elapsed. If the predetermined time T has elapsed, the process proceeds to step S313. If the predetermined time T has not elapsed, the determination is repeated until the predetermined time T elapses.

  In step S313, a pressurization control cancellation request is output to the brake ECU 60 as in step S108. That is, the pressurization of the wheel cylinder pressure by the brake actuator 70 is stopped.

  In step S314, as in step S109, both the first relay 90a and the second relay 90b are returned to the connected (ON) state, and the current process is terminated.

  As described above, the vehicle control device 1 (idle stop ECU 50) according to the present embodiment fails to start the engine 10, and even if the vehicle speed of the vehicle is equal to or higher than the predetermined speed Vth, When the cause of the start failure is not the deterioration of the main battery 20, the engine 10 is tried to be restarted. Therefore, when the restart is successful, the negative pressure supply from the vacuum pump 13 to the brake booster 15 is resumed, so that the vehicle can be stopped appropriately according to the driver's brake operation. Further, since the vehicle is stopped according to the driver's brake operation regardless of the intervention, the driver does not feel uncomfortable as when the braking force is generated regardless of the brake operation.

  Further, in the vehicle control device 1 (idle stop ECU 50) according to the present embodiment, the negative pressure of the brake booster 15 is higher than the predetermined pressure Pth even when the start failure of the engine 10 is not the deterioration of the main battery 20. If it is low, or if the remaining capacity of the sub-battery 30 is lower than the predetermined capacity SOCth, the restart of the engine 10 is not attempted. Then, by applying the wheel cylinder pressure to the brake actuator 70 via the brake ECU 60, a braking force is generated regardless of the brake operation, and the vehicle is stopped. Accordingly, when there is no more than a predetermined margin in securing the braking force in the case where the attempt to restart fails, priority can be given to stopping the vehicle more reliably than reducing the uncomfortable feeling to the driver.

  In this example, for example, a condition regarding the negative pressure of the brake booster is imposed in consideration of the case where the driver performs a brake operation and stops the vehicle during the restart. Whether or not the engine 10 is restarted may be determined based only on the capacity-related conditions. That is, if the cause of the start failure of the engine 10 is not the deterioration of the main battery 20 and the remaining capacity of the sub battery 30 is equal to or greater than the predetermined capacity SOCth, the restart of the engine 10 is performed regardless of the negative pressure of the brake booster 15. You may try. Even if the restart fails, if the remaining capacity of the sub-battery 30 is sufficient, the brake actuator 70 is pressurized to generate a braking force regardless of the brake operation by stopping the vehicle. Because it can.

  Further, at least one of the predetermined pressure Pth and the predetermined capacity SOCth may not be a constant value. That is, the negative pressure of the brake booster 15 and the remaining capacity of the sub-battery 30 necessary for generating a braking force to appropriately stop the vehicle before stopping (running) vary depending on the vehicle speed of the vehicle. It may be changed according to. For example, when the predetermined pressure Pth or the predetermined capacity SOCth is set to a constant value, it is necessary to determine the predetermined pressure Pth or the predetermined capacity SOCth on the assumption that the vehicle is stopped from a predetermined permission speed Vis. Therefore, by changing at least one of the predetermined pressure Pth and the predetermined capacity SOCth according to the vehicle speed, it is possible to reduce the uncomfortable feeling given to the driver when the engine 10 is started when the vehicle speed is relatively low. it can.

  FIG. 9 is a diagram illustrating an example of a method for determining (changing) the predetermined pressure Pth and the predetermined capacity SOCth. Specifically, the vehicle speed range of the vehicle is an upper table, and a predetermined pressure Pth and a predetermined capacity SOCth corresponding to each vehicle speed range are described in a lower table.

  This example shows an example when the sub battery 30 is a lithium ion battery, a nickel metal hydride battery, or the like (in the case of a power storage device that can drive the brake actuator 70 even if the SOC is 50% or less). In addition, the interrelationship among the speeds V1, V2, V3, V4, the predetermined permitted speed Vis, and the predetermined speed Vth in the figure is Vis> V1> V2> V3> V4 = Vth. Further, the predetermined capacity SOCth is displayed as a ratio (charge rate) to full charge.

  Referring to FIG. 9, when the vehicle speed Vs is V1 ≦ Vs ≦ Vis, the predetermined pressure Pth is set to P1. Further, when the vehicle speed Vs is V2 ≦ Vs <V1, the predetermined pressure Pth is set to P2. Further, when the vehicle speed Vs is V3 ≦ Vs <V2, the predetermined pressure Pth is set to P3. Further, when the vehicle speed Vs is V4 ≦ Vs <V3, the predetermined pressure Pth is set to P4. Note that Pa> P1> P2> P3> P4> 0 with respect to the atmospheric pressure Pa.

  Further, when vehicle speed Vs is V1 ≦ Vs ≦ Vis, predetermined capacity SOCth is set to 35%. When vehicle speed Vs is V2 ≦ Vs <V1, predetermined capacity SOCth is set to 30%. When vehicle speed Vs is V3 ≦ Vs <V2, predetermined capacity SOCth is set to 25%. When vehicle speed Vs is V4 ≦ Vs <V3, predetermined capacity SOCth is set to 20%.

  Thus, the predetermined pressure Pth and the predetermined capacity SOCth are preferably set to increase as the vehicle speed of the vehicle increases.

  In this example, the predetermined pressure Pth and the predetermined capacity SOCth are set to change stepwise with respect to the change in the vehicle speed of the vehicle, but at least partly set to change continuously. May be.

  Further, the predetermined pressure Pth and the predetermined capacity SOCth may be changed according to the distance from an obstacle (a preceding vehicle or the like) ahead of the vehicle detected by the front monitoring radar 98. That is, when there is an obstacle in front of the vehicle, it is necessary to stop the vehicle before colliding with the obstacle. Therefore, as the distance from the detected obstacle becomes shorter, a larger braking force is generated. There is a need. Therefore, the predetermined pressure Pth and the predetermined capacity SOCth may be changed so as to increase as the distance from the obstacle ahead of the vehicle detected by the front monitoring radar 98 decreases.

  Further, in the present embodiment, as in the first embodiment, the deceleration illustrated in FIG. 6 is performed on the assumption that the pre-deceleration engine start pre-processing and the post-deceleration engine start failure processing illustrated in FIG. 8 are executed. An engine start process may be performed.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

  For example, in the above-described embodiment, the switching unit 90 cuts off the path for supplying power from the sub battery 30 to the starter 11. However, a circuit configuration in which power is not supplied from the sub battery 30 to the starter 11 may be employed. . That is, when the engine stop condition is satisfied at the time of deceleration of the vehicle, and the engine start condition is satisfied before the vehicle is stopped after the engine 10 is stopped, the main battery 20 of the main battery 20 and the sub battery 30 is 11 may be supplied with driving power. Thus, as in the above-described embodiment, even if the engine start by the idle stop control fails before the vehicle stops, the vehicle is forcibly stopped from a higher vehicle speed as a fail-safe function. Therefore, it is possible to reliably supply the electric power necessary for this to the brake actuator 70. Therefore, it is possible to achieve both engine stop (improvement of fuel efficiency) by idle stop control at a higher vehicle speed during vehicle deceleration and securing of a braking force for appropriately stopping the vehicle after engine stop.

  In the above-described embodiment, two batteries are mounted on the vehicle, that is, the main battery 20 and the sub-battery 30, but it is sufficient that a plurality of batteries are mounted. That is, when the engine 10 is started before the vehicle is stopped by the idle stop control, at least one of the batteries (that can supply driving power to the brake actuator 70) does not supply driving power to the starter 11. What should I do? Thereby, the remaining capacity of the battery that does not supply drive power to the starter 11 is maintained, and the same operations and effects as those of the above-described embodiment are achieved.

DESCRIPTION OF SYMBOLS 1 Vehicle control apparatus 10 Engine 11 Starter 11r Starter relay 12 Alternator 13 Vacuum pump (negative pressure production | generation part)
14 Negative pressure pipe 15 Brake booster 16 Brake pedal 17 Master cylinder 20 Main battery (first battery)
21 battery sensor (first state detector)
30 Sub-battery (second battery)
31 Battery sensor (second state detection unit)
40 Engine ECU (control unit)
50 Idle stop ECU (control unit)
60 Brake ECU (control unit)
70 Brake actuator 75, 75a-75d Wheel cylinder (braking part)
80 switching unit 80a first relay 80b second relay 90 auxiliary machine 90a first auxiliary machine 90b second auxiliary machine 92 vehicle speed sensor 94 MC pressure sensor 96 negative pressure sensor (negative pressure detecting part)
98 Forward monitoring radar (obstacle detection unit)
OL1, OL2, OLa to OLd Hydraulic line Pth Predetermined pressure SOCth Predetermined capacity Vis Predetermined permitted speed Vth Predetermined speed

Claims (8)

An engine that drives the vehicle;
A starter for starting the engine;
A negative pressure generating unit that generates a negative pressure according to the driving of the engine;
Using the negative pressure supplied from the negative pressure generation unit, a brake booster that amplifies the brake operation force,
A braking unit for generating braking force on the vehicle according to the brake operation force amplified by the brake booster;
A brake actuator configured to be able to drive the braking unit independently of the brake operation;
A first battery configured to supply at least driving power to the starter;
A second battery configured to be able to supply driving power to at least the starter and the brake actuator;
When the vehicle decelerates, the engine is stopped when a predetermined engine stop condition including that the vehicle speed of the vehicle is equal to or lower than a predetermined permitted speed is satisfied, and when the predetermined engine start condition is satisfied, the starter A control unit for starting the engine by
The first battery is satisfied when the predetermined engine stop condition is satisfied during deceleration of the vehicle, and the predetermined engine start condition is satisfied before the vehicle stops after the control unit stops the engine. And among the second batteries, the first battery supplies driving power to the starter.
Vehicle control device. A path for supplying power from the second battery to the starter;
A switching unit for switching between connection and disconnection of the path;
The controller is
When the predetermined engine stop condition is satisfied at the time of deceleration of the vehicle, and the predetermined engine start condition is satisfied before the vehicle stops after the control unit stops the engine, the switching unit Block the route,
The vehicle control device according to claim 1. The controller is
Satisfying the predetermined engine stop condition at the time of deceleration of the vehicle; after stopping the engine; failing to start when the predetermined engine start condition is satisfied before the vehicle stops; and When the vehicle speed of the vehicle is equal to or higher than a predetermined speed, the brake actuator is driven by the brake actuator, and the braking force is generated regardless of the brake operation.
The vehicle control device according to claim 1 or 2. A first state detection unit for detecting a state of the first battery including a deteriorated state;
The controller is
Satisfying the predetermined engine stop condition at the time of deceleration of the vehicle; after stopping the engine; failing to start when the predetermined engine start condition is satisfied before the vehicle stops; and If the vehicle speed of the vehicle is equal to or higher than a predetermined speed, and the first state detection unit does not detect deterioration beyond a predetermined level in the first battery, the start is attempted again.
The vehicle control device according to claim 1 or 2. A second state detection unit for detecting a state of the second battery including a remaining capacity;
The controller is
When the remaining capacity of the second battery detected by the second state detection unit is lower than a predetermined capacity, the braking unit is driven by the brake actuator without performing the attempt, and the control is performed regardless of the brake operation. Generating power,
The vehicle control device according to claim 4. A second state detection unit for detecting a state of the second battery including a remaining capacity;
The controller is
The second battery detected by the second state detection unit after the predetermined engine stop condition is satisfied at the time of deceleration of the vehicle and after the engine is stopped and before the vehicle stops. When the remaining capacity of the engine is lower than a predetermined capacity, the engine is started.
The vehicle control device according to any one of claims 1 to 3. The predetermined capacity is
It is changed according to the vehicle speed of the vehicle.
The vehicle control device according to claim 5 or 6. An obstacle detection unit that detects an obstacle ahead of the vehicle and detects a distance to the obstacle,
The predetermined capacity is
The distance is changed according to the distance detected by the obstacle detection unit.
The vehicle control device according to any one of claims 5 to 7.

Images