JP6143285B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  In recent years, the engine is automatically stopped in response to the establishment of a predetermined automatic stop condition while the engine is being driven, and then the engine is automatically operated in response to the establishment of a predetermined restart condition. Automobiles having a function to be restarted, so-called idle stop vehicles, are provided. In an idle stop vehicle, when the vehicle is stopped due to a signal or the like, the engine is stopped, so that wasteful fuel consumption can be suppressed.

  However, when the vehicle is stopped while waiting for a right or left turn at an intersection, it is desirable that the engine not be automatically stopped because it is necessary to start the vehicle immediately if it is possible to make a right or left turn.

  Thus, a system has been proposed in which the automatic stop (idle stop) of the engine is canceled when the steering angle of the steering while the vehicle is stopped is equal to or greater than a predetermined angle. As a result, when the vehicle is stopped waiting for a right or left turn at the intersection, the idle stop is canceled, so when the right and left turn is possible, the vehicle is quickly started to complete the right and left turn. be able to.

JP-A-8-61110

  In order to detect the steering angle of the steering, a steering angle sensor is required. Therefore, in a vehicle that does not include a rudder angle sensor, a rudder angle sensor must be additionally provided when the system according to the above-described proposal is adopted.

  An object of the present invention is to provide a vehicle control device that can prevent an automatic stop of a drive source in a situation where an automatic stop of the drive source is not desirable without using a steering angle sensor.

  In order to achieve the above object, a vehicle control device according to the present invention is a control device used for a vehicle that travels by a driving force generated by a driving source and whose traveling direction is changed by an operation of a steering wheel, A torque sensor for detecting a steering torque applied to the steering wheel, an automatic stop means for automatically stopping the drive source in response to the establishment of a predetermined automatic stop condition, and a steering torque detected by the torque sensor And when the steering torque detected by the torque sensor is less than the predetermined second torque threshold, the automatic stopping means prohibits the automatic stop of the drive source by the automatic stop means. And a prohibition canceling means for canceling the prohibition of the automatic stop by the prohibiting means when it continues for a continuous period of time.

  According to this configuration, when a predetermined automatic stop condition is satisfied, the drive source is automatically stopped. For example, when the vehicle is stopped in front of an intersection and waiting for a straight crossing, the automatic stop condition is satisfied, and the drive source is automatically stopped (idle stop), thereby suppressing wasteful fuel consumption. This can improve fuel efficiency.

  The steering torque applied to the steering wheel is detected by the torque sensor. When the steering torque detected by the torque sensor is greater than or equal to a predetermined first torque threshold, automatic stop of the drive source is prohibited. For example, the stop for waiting for a right or left turn at an intersection is a stop in a situation where an immediate start of the vehicle is required. When the vehicle is stopped at the intersection in order to wait for a left or right turn, the steering wheel is cut into one of the left and right sides, and in order to maintain this state, a steering torque greater than the first torque threshold is applied to the steering wheel. There are many. At this time, the automatic stop of the drive source is prohibited, so that when the vehicle can turn right or left, the vehicle can be promptly started to complete the right or left turn.

  However, for example, if a right turn lane is provided in front of an intersection where the vehicle turns right, the steering wheel is in a neutral position when the vehicle enters a right turn posture at the intersection and the automatic stop condition is not satisfied. After the vehicle enters the right turn lane, the steering wheel is returned to the neutral position, and then the automatic stop condition may be satisfied. In this case, when the automatic stop condition is satisfied, the steering torque greater than or equal to the first torque threshold is not applied to the steering wheel, so the automatic stop of the drive source is not prohibited and the drive source is automatically stopped. In addition, when the vehicle is traveling straight at a low speed in the parking lot, the automatic stop condition is satisfied without the steering torque being applied to the steering wheel exceeding the first torque threshold, and the automatic stop of the drive source is not prohibited and the drive is not performed. The source may be automatically stopped.

  Therefore, when the steering torque detected by the torque sensor falls below a predetermined second torque threshold while the automatic stop of the drive source is prohibited, the prohibition of the automatic stop is not immediately released and the steering is After the state where the torque is less than the second torque threshold continues for a predetermined duration, the prohibition of automatic stop is released. Thereby, it is possible to prevent the drive source from being automatically stopped under circumstances where it is not desirable to automatically stop the drive source, such as before turning right or left at an intersection or during traveling in a parking lot.

  And since the steering angle sensor is not required to prevent the automatic stop of the drive source in a situation where the automatic stop of the drive source is not desirable, it is possible to avoid the cost increase due to the additional provision of the steering angle sensor. it can.

  For example, since a vehicle equipped with an electric power steering device is usually equipped with a torque sensor for detecting a steering torque applied to a steering wheel, the drive source can be automatically stopped using this torque sensor. It is possible to prevent the drive source from being automatically stopped under an undesirable situation. Therefore, in a vehicle equipped with the electric power steering device, the cost reduction effect can be exhibited more remarkably.

  The vehicular control device sets a duration based on the steering torque detected by the torque sensor within a predetermined time traced from the time when the steering torque detected by the torque sensor falls below the second torque threshold. The duration setting unit may further include a setting unit, and the duration may be set to a longer time as the value of the steering torque within a predetermined time is larger.

  According to this configuration, the duration time from when the steering torque drops below the second torque threshold until the prohibition of the automatic stop of the drive source is released is set to an appropriate time according to the operation state of the steering wheel. Can do. Accordingly, for example, during small steering such as correction steering, the duration is set to a short time, so that it is possible to prevent the automatic stop of the drive source from being prohibited more than necessary. On the other hand, since the duration is set to a long time at the time of steering by the active operation of the steering wheel, it is possible to prevent the drive source from being automatically stopped in a situation where it is not desirable to automatically stop the drive source.

  According to the present invention, without using a rudder angle sensor, it is possible to prevent an automatic stop of a drive source in a situation where an automatic stop of the drive source is not desirable, such as before turning right or left at an intersection or during traveling in a parking lot. it can.

FIG. 1 is a block diagram illustrating a configuration of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied. FIG. 2 is a flowchart showing the flow of idle stop control. FIG. 3 is a flowchart showing the flow of IDS prohibition flag setting processing. FIG. 4 is a diagram illustrating an example of changes in the state of the steering torque and the IDS prohibition flag. FIG. 5 is a flowchart showing the flow of the delay time setting process. FIG. 6 is a diagram showing the relationship between the steering torque and the delay time.

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

  FIG. 1 is a block diagram illustrating a configuration of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied.

  The idle stop vehicle 1 is an automobile that uses the engine 2 as a drive source. The idle stop vehicle 1 has an idle stop function. In the idle stop function, the engine 2 is stopped (idle stop) in response to the establishment of a predetermined automatic stop condition while the engine 2 is being driven, and then in the idle stop state in response to the establishment of the predetermined restart condition thereafter. This is a function for releasing the engine 2 and restarting the engine 2.

The output of the engine 2 includes a torque converter 3 and a continuously variable transmission (CVT: Continuously
Variable transmission) 4 is transmitted to the drive wheels of the idle stop vehicle 1.

  A starter (starting motor) 5 is provided along with the engine 2. The stopped engine 2 starts after cranking by the starter 5.

  An alternator 6 is provided in association with the engine 2.

  The rotation of the output shaft of the engine 2 is transmitted to the rotation shaft (rotor) of the alternator 6. When the rotating shaft of the alternator 6 rotates, the rotation is converted into electric power, and electric power is output from the alternator 6.

The idle stop vehicle 1 includes an electric power steering device (EPS: Electric
Power Steering) 7 is installed.

  The electric power steering device 7 is provided with a motor 8. When the driving force of the motor 8 is transmitted to the steering mechanism 9, the operation of the steering wheel included in the steering mechanism 9 is assisted.

  The idle stop vehicle 1 is provided with an ABS actuator 10 for ABS (Antilock Brake System) control. The ABS actuator 10 incorporates a valve for controlling the hydraulic pressure of the wheel cylinder provided in the brake of each wheel, a pump for returning the brake fluid to the master cylinder, and the like. The hydraulic pressure transmitted from the master cylinder to the ABS actuator 10 is distributed and transmitted to each wheel cylinder. A braking force is applied to the wheel by the hydraulic pressure of the wheel cylinder.

  The idle stop vehicle 1 is further provided with a battery 11.

  The battery 11 is charged with electric power output from the alternator 6. The battery 11 is electrically connected to the starter 5 and the motor 8 of the electric power steering device 7. Driving power is supplied from the battery 11 to the starter 5 and the motor 8. A relay 12 is interposed on a power supply path from the battery 11 to the starter 5.

  The idle stop vehicle 1 is provided with a plurality of ECUs (electronic control units) including a CPU and a memory. The ECU includes an engine ECU 21, a CVT ECU 22, an ABS ECU 23, an EPS ECU 24, and an idle stop ECU 25. The engine ECU 21, the CVTECU 22, the ABS ECU 23, the EPS ECU 24, and the idle stop ECU 25 can communicate with each other using a CAN (Controller Area Network) communication protocol.

  The engine 2 is connected to the engine ECU 21 as a control target.

  The CVT ECU 22 is connected to the continuously variable transmission 4 as a control target.

  The ABS ECU 23 is connected to the ABS actuator 10 as a control target. The ABS ECU 23 includes a wheel speed sensor 26 for detecting the rotational speed (wheel speed) of each wheel, a hydraulic pressure sensor 27 for detecting the hydraulic pressure of a master cylinder (not shown), and a brake pedal (not shown). Brake switch 28 is connected to detect whether or not The ABS ECU 23 calculates the wheel speed of each wheel based on the detection signal input from the wheel speed sensor 26, and obtains the average value of each wheel speed as the vehicle speed (body speed), for example. Further, the ABS ECU 23 acquires the hydraulic pressure of the master cylinder based on the detection signal input from the hydraulic pressure sensor 27. For example, the brake switch 28 is turned on when the brake pedal is depressed, and the ABS ECU 23 determines whether the brake pedal is depressed based on an on / off signal input from the brake switch 28.

  The EPS ECU 24 is connected to the motor 8 of the electric power steering device 7 as a control target. The EPS ECU 24 is connected to a torque sensor 29 for detecting a steering torque applied to the steering wheel of the steering mechanism 9. The EPS ECU 24 acquires the steering torque based on the detection signal input from the torque sensor 29.

  The relay 12 is connected to the idle stop ECU 25 as a control target. The idle stop ECU 25 executes control for idle stop function (idle stop control). For idle stop control, information such as the engine speed is input from the engine ECU 21 to the idle stop ECU 25, and whether the wheel speed of each wheel, the vehicle speed, the hydraulic pressure of the master cylinder, and the brake pedal are depressed from the ABS ECU 23. Information on whether or not is input, and steering torque is input from the EPS ECU 24.

  The steering torque input from the EPS ECU 24 is stored in a predetermined area of the memory of the idle stop ECU 25 using a FIFO (First In First Out) method. Thus, the steering torque input from the EPSECU 24 is held in the memory of the idle stop ECU 25 during a period up to a time point that is a predetermined time (for example, 1 second) from the current time point.

  FIG. 2 is a flowchart showing the flow of idle stop control.

  In the idle stop control, the idle stop ECU 25 repeatedly determines whether or not a predetermined automatic stop condition is satisfied (step S1). The automatic stop condition is, for example, a condition that the vehicle speed is 9 km / h or less and the hydraulic pressure (brake hydraulic pressure) of the master cylinder is 0.4 MPa or more.

  When the automatic stop condition is satisfied (YES in step S1), the idle stop ECU 25 determines whether or not the IDS prohibition flag provided in the memory of the idle stop ECU 25 is off (step S2). The IDS prohibition flag is a flag indicating whether or not idling stop of the engine 2 is prohibited.

  When the IDS prohibition flag is on (NO in step S2), it is determined again whether or not the automatic stop condition is satisfied (step S1).

  If the automatic stop condition is satisfied and the IDS prohibition flag is OFF (YES in Step S2), an engine stop command is output from the idle stop ECU 25 to the engine ECU 21, and the engine ECU 21 stops the engine 2 (Step S2). S3).

  While the engine 2 is stopped, the idle stop ECU 25 repeatedly determines whether or not a predetermined restart condition is satisfied (step S4). The restart condition is, for example, a condition that the foot is released from the brake pedal.

  When the foot is released from the brake pedal and the restart condition is satisfied (YES in step S4), the relay 12 is turned on by the idle stop ECU 25. When the relay 12 is turned on, the engine 2 is started through cranking by the starter 5 (step S5), and the idle stop control is ended.

  FIG. 3 is a flowchart showing the flow of IDS prohibition flag setting processing. FIG. 4 is a diagram illustrating an example of changes in the state of the steering torque and the IDS prohibition flag.

  In parallel with the idle stop control, the IDS prohibition flag setting process is repeatedly executed by the idle stop ECU 25.

  In the IDS prohibition flag setting process, first, whether or not the steering torque input from the EPSECU 24, that is, the steering torque applied to the steering wheel of the steering mechanism 9 is equal to or greater than a predetermined IDS prohibition torque threshold (first torque threshold). Is repeatedly determined (step S11). The IDS prohibition torque threshold is set to 0.5 N · m, for example.

  When a steering torque equal to or greater than the IDS prohibition torque threshold is applied to the steering wheel (YES in step S11), the IDS prohibition flag provided in the memory of the idle stop ECU 25 is turned on (1 is set in the IDS prohibition flag) (step S12). , Time T1).

  Thereafter, the steering torque input from the EPS ECU 24 is acquired, and it is repeatedly determined whether or not the steering torque has decreased below a predetermined IDS permission torque threshold (second torque threshold) (step S13). The IDS permission torque threshold value is set to the same value as the IDS prohibition torque threshold value, for example.

  When the steering torque falls below the IDS permission torque threshold (YES in step S13, time T2), measurement of the elapsed time from that time (the time during which the state where the steering torque is less than the IDS permission torque threshold continues) starts. Is done. Then, it is determined whether or not the measured time has reached a delay time (duration) set by a delay time setting process described later (step S14).

  Until the state where the steering torque is less than the IDS permission torque threshold continues for the delay time (NO in step S14), it is determined again whether the steering torque is smaller than the IDS permission torque threshold (step S13).

  If the steering torque rises above the IDS permission torque threshold before the state where the steering torque is less than the IDS permission torque threshold continues for the delay time (NO in step S13, time T3), the time measured so far It is cleared to 0 (step S15). Thereafter, it is repeatedly determined whether or not the steering torque has dropped below the IDS permission torque threshold (step S13).

  When the steering torque falls below the IDS permission torque threshold (time T4) and the state continues for the delay time (YES in step S14), the IDS prohibition flag is turned off (the IDS prohibition flag is set to 0) ( Step S16, time T5).

  FIG. 5 is a flowchart showing the flow of the delay time setting process. FIG. 6 is a diagram showing the relationship between the steering torque and the delay time.

  During the idle stop control, the idle time ECU 25 repeatedly executes the delay time setting process.

  In the delay time setting process, it is repeatedly determined whether or not the steering torque input from the EPS ECU 24 is less than the IDS permission torque threshold (step S21).

  When the steering torque falls below the IDS permission torque threshold value (YES in step S21), the steering torque history stored in the memory of the idle stop ECU 25, that is, the time period from the present time to the time point that is a predetermined time later is written in the memory. The steering torque is read (step S22).

  Then, a delay time is set based on the history of the steering torque (step S23). Specifically, the average value of the steering torque history read from the memory is calculated. Then, based on the relationship between the steering torque (history average value) and the delay time shown in FIG. 6, the delay time corresponding to the average value of the steering torque history is set. The relationship between the steering torque and the delay time is stored in the memory of the idle stop ECU 25. For example, when the steering torque is 0.5 N · m and 1.0 N · m, the delay time is 3 seconds and 5 seconds, respectively. It is set so that the delay time increases monotonously from 3 seconds as the steering torque increases within a range of 0.5 N · m or more.

  When the delay time is set in this way, the delay time setting process ends.

  As described above, when a predetermined automatic stop condition (the vehicle speed is 9 km / h or less and the hydraulic pressure of the master cylinder is 0.4 MPa or more) is satisfied, the engine 2 is automatically stopped. For example, when the idle stop vehicle 1 is stopped in front of an intersection for waiting straight ahead, the automatic stop condition is satisfied, and the engine 2 is automatically stopped (idle stop), so that wasted fuel is consumed. The fuel consumption can be improved by suppressing the fuel consumption.

  The torque sensor 29 detects the steering torque applied to the steering mechanism 9 (steering wheel). When the steering torque detected by the torque sensor 29 is equal to or greater than the IDS prohibition torque threshold, the automatic stop of the engine 2 is prohibited. For example, a stop for waiting for a right or left turn at an intersection is a stop in a situation where an immediate start of the idle stop vehicle 1 is required. When the idle stop vehicle 1 is stopped at the intersection to wait for a left or right turn, the steering mechanism 9 is cut into one of the left and right sides, and in order to maintain this state, the steering mechanism 9 is steered above the IDS prohibition torque threshold. Torque is often applied. At this time, the automatic stop of the engine 2 is prohibited, so that when the right / left turn is possible, the idle stop vehicle 1 can be quickly started to complete the right / left turn.

  Further, in the state where the automatic stop of the engine 2 is prohibited, when the steering torque detected by the torque sensor 29 falls below the IDS permission torque threshold, the prohibition of the automatic stop is not immediately released, and the steering torque After the state where is less than the IDS permission torque threshold continues for the delay time, the prohibition of automatic stop is released. As a result, the steering torque was not accidentally applied to the steering wheel immediately before the automatic stop condition was satisfied, but the automatic stop of the engine 2 is not desirable, such as before turning right or left at an intersection or while traveling in a parking lot. It is possible to prevent the engine 2 from being automatically stopped when it is below.

  And since the steering angle sensor is not required in order to prevent the automatic stop of the engine 2 in the situation where the automatic stop of the engine 2 is not desirable, it is possible to avoid an increase in cost by additionally providing the steering angle sensor. it can.

  The idle stop vehicle 1 is equipped with an electric power steering device 7, and a torque sensor 29 is attached to the electric power steering device 7. Therefore, in the idle stop vehicle 1, the torque sensor 29 can be used to prevent the engine 2 from being automatically stopped in a situation where the engine 2 is not desired to be automatically stopped. Therefore, in the idle stop vehicle 1, the cost reduction effect can be exhibited more remarkably.

  The delay time is such that the value of the steering torque is large based on the steering torque detected by the torque sensor 29 within a predetermined time retroactive from the time when the steering torque detected by the torque sensor 29 falls below the IDS permission torque threshold. It is set to a longer time.

  According to this configuration, the delay time from when the steering torque drops below the IDS permission torque threshold to when the prohibition of the automatic stop of the engine 2 is released is set to an appropriate time according to the operation status of the steering mechanism 9. be able to. For example, at the time of small steering such as correction steering, since the delay time is set to a short time, it is possible to prevent the automatic stop of the engine 2 from being prohibited more than necessary. On the other hand, at the time of steering by the active operation of the steering mechanism 9, the delay time is set to a long time, so that it is possible to prevent the engine 2 from being automatically stopped in a situation where the automatic stop of the engine 2 is not desirable.

  As mentioned above, although one Embodiment of this invention was described, this invention can be implemented with another form.

  For example, in the above-described embodiment, the delay time is set based on the average value of the steering torque history within the predetermined time stored in the memory of the idle stop ECU 25. Alternatively, based on the maximum value of the history of steering torque within a predetermined time, the delay time may be set longer as the maximum value increases. However, in the configuration in which the delay time is set based on the average value of the steering torque, the influence of noise mixed in the signal output from the torque sensor 29 can be eliminated.

  Also, the delay time may be set based on the time change rate (differential value) of the steering torque within a predetermined time. For example, the delay time may be set longer as the time change rate is larger.

  Also, the IDS permission torque threshold is set to the same value (for example, 0.5 N · m) as the IDS prohibition torque threshold. The IDS prohibition torque threshold and the IDS permission torque threshold may be different from each other. For example, the IDS permission torque threshold may be smaller than the IDS prohibition torque threshold.

  Furthermore, the automatic stop condition for idle stop is that the vehicle speed is 9 km / h or less and the brake fluid pressure (fluid pressure of the master cylinder) is 0.4 MPa or more. However, the automatic stop condition is not necessarily limited to this condition. It is not limited to.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1 Idle stop car (vehicle)
2 Engine (drive source)
9 Steering mechanism (steering wheel)
25 Idle stop ECU (automatic stop means, prohibition means, prohibition release means, duration setting means)
29 Torque sensor

Claims (1)

A control device used for a vehicle that travels by a driving force generated by a driving source and whose traveling direction is changed by an operation of a steering wheel,
A torque sensor for detecting a steering torque applied to the steering wheel;
Automatic stop means for automatically stopping the drive source in response to the establishment of a predetermined automatic stop condition;
Prohibiting means for prohibiting automatic stop of the drive source by the automatic stop means when a steering torque detected by the torque sensor is not less than a predetermined first torque threshold;
A prohibition canceling means for canceling the prohibition of automatic stop by the prohibiting means when a state where the steering torque detected by the torque sensor is less than a predetermined second torque threshold value continues for a predetermined duration ;
A duration setting means for setting the duration based on the steering torque detected by the torque sensor within a predetermined time that goes back from the time point when the steering torque detected by the torque sensor falls below the second torque threshold. look including a door,
The duration control means sets the duration to a longer time as the value of the steering torque within the predetermined time is larger .

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