JP2016120775A - Vehicular control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular control system capable of realizing both a vehicle state association with a driver's intention of intentionally automatically starting an engine in an N range state and a vehicle state associated with a driver's intention of unintentionally automatically starting the engine in the N range state.SOLUTION: Included are an engine control unit that autonomously starts an engine when a predetermined starting condition is satisfied, a braking force retention unit that retains the braking force of a vehicle when the vehicle is at a halt until the engine is automatically started after the engine is automatically stopped, and that retains the braking force under a predetermined condition even after the automatic start is initiated. When the engine is automatically stopped and the vehicle is halted, if the predetermined starting condition is satisfied with the shift position of the vehicle set to a neutral position, as long as the duration of the neutral position exceeds a predetermined time, the braking force retention unit releases retention of the braking force.SELECTED DRAWING: Figure 3

Description

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

  Conventionally, a vehicle having an idling stop function (hereinafter referred to as an idling stop vehicle) that automatically stops an engine when a predetermined stop condition is satisfied and automatically starts the engine when a predetermined start condition is satisfied is known. .

  As such an idling stop vehicle, a vehicle having a function (hill hold function) for maintaining a braking force for maintaining the stop during the stop from the automatic stop of the engine to the completion of the automatic start has been proposed (for example, Patent Document 1). ).

  In this way, the braking force that maintains the stop until the completion of the automatic start of the engine is maintained, so that the holding of the braking force is released before the creep force is generated in the vehicle equipped with the automatic transmission, and the vehicle stops on the slope. It is possible to avoid a situation in which the existing vehicle moves backward.

JP 2000-313253 A

  By the way, the braking force is normally held until the completion of the automatic engine start, such as a shift range in which the vehicle can generate a creep force, such as a D (drive) range or an R (reverse) range. This is the case. That is, normally, when a predetermined start condition is satisfied with the shift range set to the N (neutral) range, the braking force is not held after the engine is started automatically (braking force holding). Is released). When the shift range is set to the N range (the shift range in which engine power is not transmitted to the drive wheels), the vehicle is in a neutral state, for example, it is desired to move the vehicle using its own weight on a downhill. This is because it is considered to reflect the driver's intention.

  However, when such a configuration is adopted, inconvenience may occur in the following situation.

  For example, it is assumed that the vehicle is moved backward by making a shift change to the R range while releasing the engine after the engine has been automatically stopped in the D range state, releasing the brake operation. Normally, the driver releases the brake operation after performing a shift change from D range → N range → R range along the shift pattern. Therefore, in such a case, when the R range is set, the predetermined engine start condition is satisfied and the engine is started automatically, and the braking force of the vehicle is maintained until the engine is automatically started. On the other hand, depending on the driver, the brake operation may be released when the N range is set during the shift change from the D range to the R range. Then, because the release of the brake operation satisfies the predetermined start condition in the N range state and the holding of the braking force of the vehicle is released, for example, the driver wants to reverse the vehicle in the upward direction on the downhill. Regardless, the vehicle may move unintentionally in the downward direction.

  Therefore, in view of the above problems, when the automatic start of the engine is started in the N range state, the vehicle state corresponding to the driver's intention to intentionally automatically start the engine in the N range state, and the intention An object of the present invention is to provide a vehicle control device capable of achieving both realization of the vehicle state corresponding to the driver's intention to automatically start the engine in the N range state.

In order to achieve the above object, in one embodiment, a vehicle control device includes:
An engine that drives the vehicle;
An engine control unit that automatically stops the engine when a predetermined stop condition is satisfied, and automatically starts the engine when a predetermined start condition is satisfied;
A braking force holding unit that holds the braking force of the vehicle at least during the stop of the vehicle from the automatic stop to the start of the automatic start, wherein the braking force is maintained under a predetermined condition even after the start of the automatic start. A braking force holding unit that continues holding
The braking force holding part is
When the engine is stopped automatically and the vehicle is stopped, the predetermined start condition is satisfied in a state where the shift position of the vehicle is a neutral position, and the duration of the neutral position exceeds a predetermined time. If so, the holding of the braking force is released.

  According to the present embodiment, when the automatic start of the engine is started in the N range state, the vehicle state corresponding to the driver's intention to intentionally automatically start the engine in the N range state; It is possible to provide a vehicle control device capable of realizing both a vehicle state corresponding to a driver's intention to automatically start the engine in the N range state unintentionally.

It is a block diagram showing an example of composition of vehicles containing a control device concerning this embodiment. It is a flowchart which shows notionally an example of the brake release control process corresponding to D range or R range by the control apparatus (idle stop ECU) which concerns on this embodiment. It is a flowchart which shows notionally an example of the brake release control process corresponding to N range by the control apparatus (idle stop ECU) which concerns on this embodiment.

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

  FIG. 1 is a block diagram illustrating an example of a configuration of a vehicle including a control device 1 according to the present embodiment.

  The control device 1 holds a braking force for maintaining the vehicle stopped between the automatic stop of the engine 10 by the idle stop function and the start of the automatic start, and under predetermined conditions after the automatic start of the engine 10 is started. Control for releasing the holding of the braking force is executed.

  Note that “idle stop” means that the engine 10 is automatically stopped and automatically started according to a predetermined condition, and whether the vehicle state when the engine 10 is automatically stopped is a traveling state (deceleration state). It is a concept regardless of whether the vehicle is stopped.

  The control device 1 includes an engine 10, a starter 11, an alternator 12, a battery 20, an engine ECU 30, an idle stop ECU 40, an MC pressure sensor 42, a vehicle speed sensor 44, a shift range sensor 46, an engine speed sensor 48, a brake ECU 50, and a brake actuator 52. Etc.

  The engine 10 is an internal combustion engine that supplies power for driving the vehicle.

  The starter 11 is a starting unit that starts the engine 10 and is driven by power supplied from the battery 20.

  The alternator 12 is a DC generator that is driven by the power of the engine 10, and includes, for example, an AC generator and a rectifier that converts the three-phase AC power generated by the AC generator into DC. Specifically, the power of the engine 10 is transmitted from the crankshaft 10c via the belt 10b, and the alternator 12 can generate power.

  The battery 20 is a power storage means that is electrically connected to the starter 11, the engine ECU 30, the idle stop ECU 40, the brake ECU 50, other auxiliary loads (electrical components), and the like, and can supply electric power thereto. For example, a lead battery or the like may be used, and the rated voltage (both ends voltage) is about 12V. The battery 20 is connected to the alternator 12 and can charge the electric power generated by the alternator 12.

  The engine ECU 30 is an electronic control unit that controls the engine 10. For example, it may be constituted by a microcomputer, and various control processes may be executed by executing various programs stored in the ROM on the CPU. Specifically, based on the accelerator opening, vehicle speed, crank angle, cam angle, engine speed, etc., the fuel injector (fuel injection timing, amount, etc.), spark plug (ignition timing, etc.), intake / exhaust valve of the engine 10 (Opening / closing timing, etc.) are controlled.

  Further, the engine ECU 30 controls the relay 11r provided in the power supply path from the battery 20 to the starter 11 to drive the starter 11 and start the engine 10. For example, when an ignition switch (IG switch) is turned on by the driver, a corresponding signal (IG-ON signal) is input to the engine ECU 30, and the engine ECU 30 starts the engine 10 by energizing the relay 11r. Further, the engine ECU 30 stops the engine 10 by cutting fuel supply to the engine 10. For example, when the driver turns off the IG switch, a corresponding signal (IG-OFF signal) is input to the engine ECU 30, and the engine ECU 30 cuts fuel supply to each cylinder of the engine 10 at a predetermined timing. The engine 10 is stopped.

  Further, the engine ECU 30 stops the engine 10 by cutting the fuel supply in response to an engine stop request received from an idle stop ECU 40 described later. Further, the engine ECU 30 drives the starter 11 by starting the engine 10 by controlling the relay 11r in response to the engine start request received from the idle stop ECU 40. As described above, the engine ECU 30 directly executes control of automatic stop or automatic start of the engine 10 in the idle stop function of the vehicle.

  The idle stop ECU 40 is an electronic control unit that performs idle stop control of the vehicle. For example, it may be constituted by a microcomputer, and various control processes may be executed by executing various programs stored in the ROM on the CPU.

  The idle stop ECU 40 determines whether or not a predetermined engine stop condition is satisfied, and outputs an engine stop request to the engine ECU 30 when the engine stop condition is satisfied. For example, the engine stop condition is that the master cylinder pressure (hereinafter referred to as MC pressure) is equal to or higher than a predetermined depression pressure (braking operation is performed), and the vehicle speed of the vehicle is equal to or lower than a predetermined permitted speed. Including falling.

  The predetermined permitted speed is a concept including 0 (zero). That is, the idle stop ECU 40 automatically stops the engine 10 when the vehicle is decelerated (running) or stopped.

  Further, the idle stop ECU 40 determines whether or not a predetermined engine start condition is satisfied, and outputs an engine start request to the engine ECU 30 when the engine start condition is satisfied. For example, the engine start condition includes a plurality of engine start conditions such that the MC pressure is equal to or lower than a predetermined release pressure (braking operation is released), the shift range is changed and maintained for a predetermined time. The idle stop ECU 40 outputs an engine start request when any one of the plurality of engine start conditions is satisfied.

  As will be described later, the idle stop ECU 40 is communicably connected to the MC pressure sensor 42, the vehicle speed sensor 44, and the like through an in-vehicle LAN or the like. Thereby, the idle stop ECU 40 can acquire the MC pressure (corresponding MC pressure signal) and the vehicle speed (corresponding vehicle speed signal). The engine stop condition and the engine start condition include, for example, the above-described conditions related to the MC pressure, the vehicle speed, and the shift range, for example, the number of revolutions of the engine 10, the coolant temperature, and the state of the battery 20 (current, voltage, temperature, charge state, The condition regarding the deterioration state etc. may be included.

  Further, the idle stop ECU 40 executes a control process related to the hill hold function associated with the idle stop function of the vehicle. In other words, the idle stop ECU 40 has a braking force for maintaining the stop of the vehicle during the stop of the vehicle from the automatic stop of the engine 10 (output of the engine stop request) to the start of automatic start (output of the engine start request). The control to hold (brake holding control) is executed. For example, when the engine 10 is automatically stopped when the vehicle is decelerated, the idle stop ECU 40 outputs a brake holding request to the brake ECU 50 when determining that the vehicle has stopped.

  Further, after the automatic start of the engine 10 is started, the idle stop ECU 40 executes control (brake release control) for releasing the holding of the braking force for maintaining the vehicle stopped under a predetermined condition. The idle stop ECU 40 determines release of holding of the braking force for maintaining the vehicle stopped based on a predetermined condition, and outputs a brake release request to the brake ECU 50. Details of the brake release control will be described later.

  The MC pressure sensor 42 is detection means for detecting the MC pressure. The MC pressure sensor 42 is communicably connected to the idle stop ECU 40 through an in-vehicle LAN or the like, and a detection signal (MC pressure signal) corresponding to the MC pressure is transmitted to the idle stop ECU 40.

  The vehicle speed sensor 44 is a known vehicle speed detection means for detecting the vehicle speed of the vehicle. The vehicle speed sensor 44 is communicably connected to the idle stop ECU 40 through an in-vehicle LAN or the like, and a detection signal (vehicle speed signal) corresponding to the vehicle speed is transmitted to the idle stop ECU 40.

  The shift range sensor 46 is a shift position detection unit that detects a shift range (shift position) in an automatic transmission (not shown) of the vehicle. For example, a shift range selected by a driver operating in a shift device that is disposed in a shift device for selecting a shift range is detected. The shift range sensor 46 is communicably connected to the idle stop ECU 40 through an in-vehicle LAN or the like, and a detection signal (shift range signal) corresponding to the shift range is transmitted to the idle stop ECU 40.

  The shift range includes, for example, a P range (parking position), an R range (reverse drive position), an N range (neutral position), a D range (travel position), and the like. The D range includes a shift range for selecting a specific gear position.

  The engine speed sensor 48 is a known engine speed detecting means for detecting the speed of the engine 10 (every unit time, for example, the number of revolutions per minute (rpm)). For example, the engine speed sensor 48 includes a crank angle sensor, a cam angle sensor, and the like. The engine speed sensor 48 is communicably connected to the idle stop ECU 40 through an in-vehicle LAN or the like, and a detection signal (engine speed signal) corresponding to the speed of the engine 10 is transmitted to the idle stop ECU 40.

  The brake ECU 50 is an electronic control unit that executes braking control of the vehicle (control of the operating state of the brake device of the vehicle). Specifically, control of the brake actuator 52 which operates the hydraulic brake device arranged on each wheel of the vehicle is executed. The brake ECU 50 may be configured by, for example, a microcomputer or the like, and may execute various control processes by executing various programs stored in the ROM on the CPU.

  The brake ECU 50 is communicably connected to the idle stop ECU 40 through an in-vehicle LAN or the like. Further, the brake ECU 50 is directly connected to the brake actuator 52 so as to be communicable.

  The brake ECU 50 controls the output (wheel cylinder pressure) of the brake actuator 52 in response to a brake holding request or a brake release request received from the idle stop ECU 40. Then, the brake holding after the engine stop request and the brake release after the engine start request are executed. That is, at least from the output of the engine stop request by the idle stop ECU 40 to the output of the engine start request, the braking force for automatically maintaining the vehicle stopped is maintained regardless of the brake operation by the driver. Specifically, the wheel cylinder pressure corresponding to the braking force capable of maintaining the stop state of the vehicle is automatically generated according to the brake holding request and the MC pressure information from the idle stop ECU 40. More specifically, for example, the wheel cylinder pressure corresponding to the maximum value of the MC pressure by the driver's brake operation immediately before the vehicle stops may be automatically generated (peak hold control). As a result, the maximum braking force immediately before the vehicle is stopped is generated, so that the vehicle can be kept stopped. Further, in response to a brake release request from the idle stop ECU 40, the wheel cylinder pressure is reduced in a predetermined pressure reduction pattern. For example, if the wheel cylinder pressure is suddenly reduced, the vehicle may jump forward or backward by a creep driving force corresponding to the torque of the engine 10 to be started. Good.

  Note that the functions of the engine ECU 30, the idle stop ECU 40, and the brake ECU 50 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 30, the idle stop ECU 40, and the brake ECU 50 may be realized by another ECU. Further, the engine ECU 30, the idle stop ECU 40, and the brake ECU 50 may realize part or all of the functions of other ECUs. For example, part or all of the functions of the engine ECU 30 may be realized by the idle stop ECU 40. Further, part or all of the functions of the brake ECU 50 may be realized by the idle stop ECU 40.

  Next, a characteristic operation by the control device 1 (idle stop ECU 40) according to the present embodiment, that is, brake release control will be described.

  FIG.2 and FIG.3 is a flowchart which shows notionally an example of the brake release control by the control apparatus 1 (idle stop ECU40) based on this embodiment. FIG. 2 conceptually shows an example of the brake release control corresponding to the D range or the R range, that is, the brake release control when the automatic start of the engine 10 is started in the state where the shift range is the D range or the R range. It is a flowchart. FIG. 3 is a flowchart conceptually showing an example of the brake release control corresponding to the N range, that is, the brake release control in the case where the automatic start of the engine 10 is started in the state where the shift range is the N range.

  First, the brake release control in the case where the automatic start of the engine 10 is started in the state where the shift range is the D range or the R range (an engine start request is output) will be described using FIG.

  The flowchart of FIG. 2 is started when the vehicle is stopped and the engine 10 is automatically stopped when the engine start condition is satisfied when the shift range is in the D range or the R range. The flowchart is repeatedly executed at predetermined time intervals after the start of execution until a brake release request is output by the idle stop ECU 40 (that is, until a process of step S104 described later is executed).

  In step S101, the idle stop ECU 40 determines whether or not an elapsed time since the engine start condition is satisfied (elapsed time since the output of the engine start request) is equal to or less than a predetermined time Tth1. The idle stop ECU 40 proceeds to step S102 when it is equal to or shorter than the predetermined time Tth1, and proceeds to step S104 when it is not shorter than the predetermined time Tth1 (exceeds the predetermined time Tth1).

  Note that the predetermined time Tth1 is a threshold value set for executing brake release when the engine 10 cannot be started due to a failure or the like, for example. The predetermined time Tth1 is, for example, the maximum value of the time that is assumed from the output of the engine start request by the idle stop ECU 40 until the start of the engine 10 is completed (the engine 10 rises to a speed capable of generating the creep driving force). It is set longer.

  In step S102, the idle stop ECU 40 determines whether or not the rotational speed of the engine 10 is equal to or less than a predetermined rotational speed Nth. The idle stop ECU 40 proceeds to step S103 when the rotational speed of the engine 10 is equal to or smaller than the predetermined rotational speed Nth, and proceeds to step S104 when it is not smaller than the predetermined rotational speed Nth (exceeds the predetermined rotational speed Nth).

  The predetermined rotational speed Nth is a threshold value for determining completion of starting of the engine 10 (reaching the rotational speed at which the vehicle can generate creep driving force).

  In step S103, the idle stop ECU 40 continues the brake holding (holding the braking force for maintaining the vehicle stopped).

  On the other hand, in step S104, the idle stop ECU 40 releases the brake holding. That is, the idle stop ECU 40 transmits a brake release request to the brake ECU 50, and ends the process according to the flowchart.

  As described above, the control device 1 according to this embodiment starts the engine 10 when the engine start condition is satisfied in the shift range (D range or R range) in which the driving force of the engine 10 is transmitted to the drive wheels. Brake holding control is continued until is completed. Thereby, when the engine 10 is automatically started in a state where the vehicle is stopped on a slope, it is possible to prevent the vehicle from moving in the downward direction of the slope against the driver's intention.

  Next, the brake release control when the automatic start of the engine 10 is started (an engine start request is output) in a state where the shift range is the N range will be described using FIG.

  The flowchart in FIG. 3 is started when the vehicle is stopped and the engine 10 is automatically stopped when the engine start condition is satisfied when the shift range is in the N range. The flowchart is repeatedly executed at predetermined time intervals after the start of execution until a brake release request is output by the idle stop ECU 40 (that is, until a process of step S203 described later is executed).

  In step S201, the idle stop ECU 40 determines whether or not the duration of the N range is equal to or shorter than a predetermined time Tth2. If the duration of the N range is equal to or shorter than the predetermined time Tth2, the idle stop ECU 40 proceeds to step S202. If not longer than the predetermined time Tth2 (when the predetermined time Tth2 is exceeded), the idle stop ECU 40 proceeds to step S203.

  It should be noted that the idle stop ECU 40 determines the shift change to the N range based on the shift range signal received from the shift range sensor 46, and simultaneously starts counting by the internal timer, thereby measuring the duration of the N range. Can do.

  In step S202, the idle stop ECU 40 continues the brake holding (holding the braking force for maintaining the vehicle stopped).

  On the other hand, in step S203, the idle stop ECU 40 releases the brake holding. That is, the idle stop ECU 40 transmits a brake release request to the brake ECU 50, and ends the process according to the flowchart.

  As described above, the control device 1 according to the present embodiment is a case where the engine start condition is satisfied in the shift range (N range) in which the driving force of the engine 10 is not transmitted to the drive wheels, and the duration of the N range. Is longer than the predetermined time Tth2, the brake holding is released. At this time, by appropriately setting the predetermined time Tth2, the vehicle state corresponding to the driver's intention to intentionally automatically start the engine 10 in the N range state is realized, and the engine 10 is unintentionally in the N range state. The vehicle state corresponding to the driver's intention to automatically start the vehicle can be realized at the same time.

  Specifically, the driver who unintentionally automatically starts the engine 10 in the N range state by releasing the brake operation in the middle of the shift change from the D range to the R range, We expect to realize the corresponding vehicle conditions. For example, considering a case where a vehicle that stops on a hill is shifted from the D range to the R range in order to move backward in the upward direction, after the automatic start of the engine 10 starts, the driver moves forward and descends. It is expected to realize a vehicle state that allows the vehicle to move backward and move upward without moving in the direction. Therefore, until the continuation time of the N range exceeds the predetermined time Tth2, even if the brake operation is released by continuing the brake holding, the vehicle is in a direction (downward direction) that is contrary to the driver's intention on the slope. It can prevent moving. That is, it is possible to realize a vehicle state corresponding to the driver's intention to automatically start the engine 10 in the N range state unintentionally.

  On the other hand, a driver's act of intentionally automatically starting the engine 10 in the N range state by releasing the brake operation or the like causes the vehicle to be in a neutral state, for example, using its own weight on a downhill. This is thought to reflect the willingness to move. Therefore, if the duration of the N range exceeds the predetermined time Tth2, the brake holding is released, so that the vehicle is in a neutral state, which corresponds to the driver's intention to intentionally automatically start the engine 10 in the N range state. A vehicle state is realized.

  As described above, the control device 1 according to this embodiment realizes the vehicle state corresponding to the driver's intention to automatically start the engine 10 in the N range state intentionally, and unintentionally the engine in the N range state. The vehicle state corresponding to the driver's intention to automatically start 10 can be realized at the same time.

  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.

1 Control device (vehicle control device)
10 Engine 11 Starter 12 Alternator 20 Battery 30 Engine ECU
40 Idle stop ECU (engine control unit, braking force holding unit)
42 MC pressure sensor 44 Vehicle speed sensor 46 Shift range sensor 48 Engine speed sensor 50 Brake ECU
52 Brake actuator

Claims (1)

An engine that drives the vehicle;
An engine control unit that automatically stops the engine when a predetermined stop condition is satisfied, and automatically starts the engine when a predetermined start condition is satisfied;
A braking force holding unit that holds the braking force of the vehicle at least during the stop of the vehicle from the automatic stop to the start of the automatic start, wherein the braking force is maintained under a predetermined condition even after the start of the automatic start. A braking force holding unit that continues holding
The braking force holding part is
When the engine is stopped automatically and the vehicle is stopped, the predetermined start condition is satisfied in a state where the shift position of the vehicle is a neutral position, and the duration of the neutral position exceeds a predetermined time. Release the holding of the braking force,
Vehicle control device.

Images