JP2013209973A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a vehicle capable of restraining a driving source from being automatically stopped, when stopping in a state of requiring instant starting of the vehicle, such as waiting for a right-left turn in an intersection, without using a steering angle sensor.SOLUTION: A torque sensor 28 is arranged for detecting a steering torque added to a steering wheel of a steering mechanism 9. When the steering torque detected by the torque sensor 28 before stopping is a predetermined turning determining threshold or more, automatic stopping of an engine 2 by idle reduction control after stopping is prohibited.

Description

  The present invention relates to a vehicle control device.

  In recent years, the engine is automatically stopped in response to establishment of a predetermined stop condition while the engine is being driven, and then the engine is automatically restarted in response to establishment of a predetermined restart condition. Automobiles having a function to be started, 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 for a vehicle that can prevent the drive source from being automatically stopped while stopping in a situation where an immediate start of the vehicle is required, such as waiting for a right or left turn at an intersection without using a steering angle sensor. It is to provide a control device.

  In order to achieve the above object, a vehicle control device according to the present invention is used in 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. The vehicle control device automatically activates the drive source in response to a torque sensor for detecting a steering torque applied to the steering wheel and when a predetermined stop condition is satisfied during driving of the drive source. Idle stop control means for stopping, and prohibiting means for prohibiting automatic stop of the drive source by the idle stop control means when the steering torque detected by the torque sensor before stopping is equal to or greater than a predetermined threshold value. .

  For example, when the vehicle is stopped waiting for a signal, the drive source is automatically stopped (idle stop), so that fuel can be improved. On the other hand, when the vehicle is stopped waiting for a right or left turn at an intersection, it is desirable that the immediate start of the vehicle is more important than the improvement of fuel consumption, and the drive source is not automatically stopped.

  For example, a vehicle including an electric power steering device is equipped with a torque sensor for detecting a steering torque applied to a steering wheel. In such a vehicle, based on the output of the torque sensor, if it is possible to accurately determine whether or not the vehicle is in a situation where an immediate start of the vehicle is required, such as a vehicle waiting for a right or left turn at an intersection, For this determination, there is no need to additionally provide a steering angle sensor.

  Prior to conceiving the present invention, the inventor of the present application, if the detected value of the steering torque by the torque sensor is not less than a predetermined value while the vehicle is stopped, as in the configuration in which the steering angle sensor is provided, We decided to stop the vehicle in a situation where it was required to start, and considered to prohibit the automatic stop of the drive source.

  However, when the steering wheel is loosened when the vehicle is waiting for a left or right turn at an intersection, the detected value of the steering torque by the torque sensor may drop below a predetermined value, and the drive source may be automatically stopped. I understood it.

  Therefore, the inventor of the present application considered that the automatic stop of the drive source is prohibited when the steering torque detected by the torque sensor is equal to or greater than a predetermined torque threshold before stopping.

  For example, when a vehicle enters a right turn posture at an intersection, the steering wheel is operated to the right, and the vehicle is brought to the center line of the road before stopping. Therefore, before stopping for waiting for a right turn at an intersection, the steering torque detected by the torque sensor becomes equal to or greater than a predetermined torque threshold. Therefore, depending on whether or not the steering torque detected by the torque sensor before stopping is greater than or equal to a predetermined torque threshold, the vehicle is required to start immediately, such as when the vehicle stops after waiting for a right or left turn at an intersection. It is possible to accurately determine whether or not the vehicle has stopped. As a result, it is possible to prevent the drive source from being automatically stopped while the vehicle is stopped in a situation where an immediate start of the vehicle is required.

  The detection timing of the steering torque used for determining whether or not it is equal to or greater than a predetermined torque threshold may be a point in time when the vehicle speed decreases to a predetermined vehicle speed greater than 0 km / h. In this case, the predetermined vehicle speed is preferably set to be equal to or lower than a normal speed at which the vehicle enters the intersection when turning right or left, for example, 10 km / less.

  A history of steering torque detected by the torque sensor is stored in a memory, and is used to determine whether or not the steering torque detected by the torque sensor a predetermined time before the stop is equal to or greater than a predetermined torque threshold. Also good.

  Furthermore, when the history of the steering torque detected by the torque sensor is stored in the memory, whether or not the average value of the steering torque detected by the torque sensor during a predetermined time until the vehicle stops is equal to or greater than a predetermined torque threshold. It may be used for such determination.

  For example, if the steering operation (steering wheel operation) fluctuates immediately before the vehicle stops in a straight-ahead posture due to a signal waiting, the torque sensor detects a steering torque that is equal to or greater than a predetermined torque threshold value, and the vehicle is stopped waiting for a signal. Nevertheless, there is a risk that the automatic stop of the drive source is prohibited.

  When the vehicle enters a right turn posture at an intersection, the steering wheel is operated to the right, and the traveling direction (steering angle) of the vehicle changes, so the wheel speed difference (rotation) between the left and right wheels of the vehicle (Speed difference) occurs. On the other hand, immediately before the vehicle stops in a straight-ahead posture due to a signal wait, even if the steering operation is slightly fluctuated, the vehicle maintains a straight-ahead posture, so that there is almost no wheel speed difference between the left and right wheels of the vehicle.

  Therefore, a wheel speed difference detecting means for detecting the wheel speed difference between the left wheel and the right wheel of the vehicle is provided, the steering torque detected by the torque sensor before stopping is equal to or greater than the torque threshold, and the wheel speed difference detection is performed. When the wheel speed difference detected by the means is equal to or greater than a predetermined wheel speed difference threshold, it is preferable that the automatic stop of the drive source is prohibited.

  As a result, even if there is a wobble of the steering wheel operation (steering wheel operation) immediately before stopping in a straight-line posture by waiting for a signal, automatic stop of the drive source is not prohibited, and while stopping while waiting for that signal, The drive source can be automatically stopped, and fuel can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that a drive source stops automatically during the stop in the condition where the immediate start of a vehicle is requested | required, without using a steering angle sensor. And since a rudder angle sensor is not required, the cost increase by providing a rudder angle sensor additionally can be prevented.

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 IDS permission flag setting processing. FIG. 3 is a graph showing changes in vehicle speed during the IDS permission flag setting process. FIG. 4 is a flowchart showing the flow of another IDS permission flag setting process. FIG. 5 is a graph showing changes in vehicle speed and steering torque.

  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 establishment of a predetermined stop condition while the engine 2 is being driven, and the idle stop state is changed in response to establishment of a predetermined restart condition thereafter. This function is released and the engine 2 is restarted.

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 by 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 is connected to a wheel speed sensor 26 for detecting the rotational speed (wheel speed) of each wheel and a hydraulic pressure sensor 27 for detecting the hydraulic pressure of a master cylinder (not shown). 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.

  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 28 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 28.

  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 the idle stop control, information such as the engine speed is input from the engine ECU 21 to the idle stop ECU 25, the wheel speed of each wheel, the vehicle speed, and the hydraulic pressure of the master cylinder are input from the ABS ECU 23, and the steering torque is output from the EPS ECU 24. Is entered.

  In the idle stop control, when the driver depresses the brake pedal while the idle stop vehicle 1 is traveling and the hydraulic pressure in the master cylinder exceeds a predetermined pressure, the idle stop ECU 25 determines whether a predetermined stop condition is satisfied. It is repeatedly judged whether or not. The stop condition is, for example, a condition that the vehicle speed is zero and a brake pedal (not shown) is continuously depressed for a certain time or more. If a stop condition is satisfied and an IDS permission flag described later is on, an engine stop command is output from the idle stop ECU 25 to the engine ECU 21, and the engine 2 is stopped by the engine ECU 21.

  For example, when the foot is released from the brake pedal while the engine 2 is stopped by the idle stop control, the restart condition is satisfied, and 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.

  FIG. 2 is a flowchart showing the flow of IDS permission flag setting processing. FIG. 3 is a graph showing changes in vehicle speed during the IDS permission flag setting process.

  During the idling stop control, the idling stop ECU 25 repeatedly executes the IDS permission flag setting process.

  In the IDS permission flag setting process, it is first determined whether or not the vehicle speed has decreased to 4 km / h (step S1). The subsequent processing is not performed until the vehicle speed drops to 4 km / h.

  When the vehicle speed drops to 4 km / h (YES in step S1), a steering torque value (hereinafter simply referred to as “torque value”) input from EPSECU 24 is acquired (step S2).

  Thereafter, it is determined whether or not the vehicle speed has decreased to 0 km / h (step S3).

  If the vehicle speed is not 0 km / h (NO in step S3), it is determined whether the vehicle speed has increased to 4 km / h or more (step S4).

  If the vehicle speed has not increased to 4 km / h or more (NO in step S4), it is determined again whether the vehicle speed has decreased to 0 km / h (step S3).

  When the vehicle speed increases to 4 km / h or more (YES in step S4), the process returns to step S1, and it is determined again whether or not the vehicle speed has decreased to 4 km / h. And if a vehicle speed falls to 4 km / h (YES of step S1), a torque value will be acquired again (step S2).

  When the vehicle speed becomes 0 km / h, it is determined whether or not the torque value acquired when the vehicle speed is 4 km / h is equal to or less than a predetermined turning determination threshold value (step S5).

  If the torque value is equal to or smaller than the turning determination threshold value (YES in step S5), the IDS permission flag provided in the memory of the idle stop ECU 25 is turned on (1 is set in the IDS permission flag) (step S6).

  On the other hand, if the torque value is larger than the turning determination threshold value (NO in step S5), the IDS permission flag provided in the memory of the idle stop ECU 25 is turned off (0 is set in the IDS permission flag) (step S7). When the IDS permission flag is turned off, the engine 2 is not automatically stopped even if the stop condition is satisfied. Accordingly, when the torque value at the time when the vehicle speed is reduced to 4 km / h is larger than the turning determination threshold value, that is, when a steering torque greater than a predetermined value for operation is applied to the steering wheel, the idle stop is performed. The automatic stop of the engine 2 by the control is prohibited.

  As described above, when the steering torque value (torque value) detected by the torque sensor 28 before stopping is equal to or greater than the predetermined turning determination threshold value, the automatic stop of the engine 2 by the idle stop control is prohibited.

  For example, when the idle stop vehicle 1 enters a right turn posture at an intersection, the steering wheel is operated in the right direction, and the idle stop vehicle 1 is brought to the center line of the road before stopping. Therefore, the torque value detected by the torque sensor 28 is equal to or greater than a predetermined turning determination threshold before stopping for a right turn at the intersection. Further, when the idle stop vehicle 1 enters a left turn posture at the intersection, the steering wheel is operated in the left direction, and the idle stop vehicle 1 is brought to the left side of the road before stopping. Therefore, the torque value detected by the torque sensor 28 is equal to or greater than a predetermined turning determination threshold before stopping for waiting for a left turn at an intersection (waiting for a pedestrian or the like to cross).

  Therefore, depending on whether or not the torque value detected by the torque sensor 28 before the stop is equal to or greater than a predetermined threshold, an immediate start of the idle stop vehicle 1 is required, such as a stop after waiting for a right or left turn at an intersection. It is possible to accurately determine whether or not the vehicle is stopped in a situation. As a result, it is possible to suppress the engine 2 from being automatically stopped while the vehicle is stopped in a situation where an immediate start of the idle stop vehicle 1 is required.

  In this way, it is possible to suppress the engine 2 from being automatically stopped while the vehicle is stopped in a situation where an immediate start of the idle stop vehicle 1 is required without using the steering angle sensor. And since a rudder angle sensor is not required, the cost increase by providing a rudder angle sensor additionally can be prevented.

  The detection timing of the steering torque used for determining whether or not it is equal to or higher than a predetermined turning determination threshold is the time when the vehicle speed is reduced to 4 km / h. The vehicle speed may be at a point when the vehicle speed has decreased to a predetermined vehicle speed greater than 0 km / h. However, the predetermined vehicle speed is preferably set to be equal to or less than a normal speed at which the idle stop vehicle 1 enters the intersection when turning right or left, for example, 10 km / h or less.

  Further, the history of the steering torque detected by the torque sensor 28 is stored in the memory of the idle stop ECU 25, and whether or not the torque value detected by the torque sensor 28 a predetermined time before the stop is equal to or greater than a predetermined threshold value. It may be used for judgment.

  Furthermore, when the history of the steering torque detected by the torque sensor 28 is stored in the memory, whether the average value of the steering torque detected by the torque sensor 28 during a predetermined time until the vehicle stops is equal to or greater than a predetermined threshold value. It may be used to determine whether or not.

  FIG. 4 is a flowchart showing the flow of another IDS permission flag setting process. FIG. 5 is a graph showing changes in vehicle speed and steering torque.

  When the IDS permission flag setting process shown in FIG. 4 is adopted instead of the IDS permission flag setting process shown in FIG. 2, as a stop condition of the engine 2 by the idle stop function, for example, when the brake pedal is depressed, A condition is adopted in which the vehicle speed of the vehicle 1 is decreased, the vehicle speed is equal to or lower than a predetermined vehicle speed (for example, 7 km / h), and the brake pedal is continuously depressed for a predetermined time or more.

  The IDS permission flag setting process shown in FIG. 4 is repeatedly executed by the idle stop ECU 25 during idle stop control, that is, while the vehicle 1 is traveling.

  In the IDS permission flag setting process shown in FIG. 4, the torque value (steering torque value detected by the torque sensor 28) input from the EPSECU 24 is stored in a fixed-capacity torque storage area provided in the memory of the idle stop ECU 25. It is stored in the form of (First In First Out) (step S11). As a result, the torque storage area always stores the torque value detected within the period from the present time to the time point that is a predetermined time backward.

  Further, it is determined whether or not the vehicle speed has decreased to a predetermined vehicle speed (step S12). The subsequent processing is not performed until the vehicle speed decreases to the predetermined vehicle speed.

  When the vehicle speed decreases to the predetermined vehicle speed (YES in step S12), the torque value stored in the torque storage area is referred to, and a period (for example, past time) from when the vehicle speed decreases to the predetermined vehicle speed to a predetermined time. The maximum torque value among the torque values stored in the torque storage area is acquired for 1000 msec) (step S13).

  Moreover, the wheel speed of each wheel input from the ABS ECU 23 is acquired when the vehicle speed drops to a predetermined vehicle speed. Then, for example, a difference in wheel speed between the left front wheel and the right front wheel (left and right wheel speed difference) is calculated (step S14).

  Thereafter, it is determined whether or not the maximum torque value is equal to or greater than a predetermined torque threshold value (step S15).

  When the idle stop vehicle 1 enters a right turn posture at an intersection, as shown by a solid line in FIG. 5, the steering wheel is operated to the right when the vehicle speed drops to a predetermined vehicle speed. The torque value detected by the sensor 28 becomes a predetermined torque threshold value (for example, 0.4 N · m) or more. However, for example, when a right turn lane is provided in front of the intersection, as shown by a two-dot chain line in FIG. 5, when the vehicle speed is higher than a predetermined vehicle speed, the steering wheel is operated in the right direction, When the vehicle speed drops to the predetermined vehicle speed, it is considered that the operation of the steering wheel is completed and the torque value detected by the torque sensor 28 is below the predetermined torque threshold.

  Therefore, not the torque value at the time when the vehicle speed is reduced to the predetermined vehicle speed, but the maximum torque value among the torque values stored in the torque storage area in the period from the time when the vehicle speed is reduced to the predetermined vehicle speed to the time point that is a predetermined time backward Is greater than or equal to a predetermined torque threshold (for example, 0.4 N · m) (step S15). Accordingly, even when the steering wheel is operated in the right direction when the vehicle speed is higher than the predetermined vehicle speed, it can be determined well whether or not the operation has been performed.

  If the maximum torque value is equal to or greater than a predetermined torque threshold value (YES in step S15), it is determined whether the left and right wheel speed difference is equal to or greater than a predetermined wheel speed difference threshold value (step S16).

  When the maximum torque value is equal to or greater than a predetermined torque threshold and the left and right wheel speed difference is equal to or greater than the predetermined wheel speed difference threshold (YES in step S16), an IDS permission flag provided in the memory of the idle stop ECU 25 Is turned off (0 is set in the IDS permission flag) (step S17). When the IDS permission flag is turned off, the engine 2 is not automatically stopped even if the stop condition is satisfied.

On the other hand, whether the maximum torque value is less than the torque threshold (NO in step S15), or
If the left and right wheel speed difference is less than the predetermined wheel speed difference threshold (NO in step S16), the IDS permission flag provided in the memory of the idle stop ECU 25 is turned on (1 is set in the IDS permission flag) ( Step S18).

  For example, when the idle stop vehicle 1 enters a right turn posture at an intersection, the steering wheel is operated to the right, and the traveling direction (steering angle) of the idle stop vehicle 1 changes. A wheel speed difference (rotational speed difference) occurs between the left wheel and the right wheel. On the other hand, for example, even if the steering operation (steering wheel operation) fluctuates immediately before the vehicle stops in a straight running posture by waiting for a signal, the idle stop vehicle 1 maintains a straight running posture. There is almost no wheel speed difference between the wheels.

  Therefore, the wheel speed difference (left and right wheel speed difference) between the left wheel and the right wheel of the idle stop vehicle 1 is obtained, the torque value detected by the torque sensor 28 before stopping is equal to or greater than the torque threshold, and the left and right wheels When the speed difference is greater than or equal to a predetermined wheel speed difference threshold, automatic stop of the engine 2 is prohibited.

  Thus, even if the steering operation (steering wheel operation) fluctuates immediately before the stop while waiting for a signal, the automatic stop of the engine 2 is not prohibited. It can be automatically stopped and fuel can be improved.

  Although two embodiments of the present invention have been described above, the present invention may be implemented in other forms, and the above-described configuration includes various designs within the scope of the matters described in the claims. Changes can be made.

1 Idle stop car (vehicle)
2 Engine (drive source)
9 Steering mechanism (steering wheel)
25 Idle stop ECU (idle stop control means, prohibition means, wheel speed difference detection means)
26 Wheel speed sensor (wheel speed difference detecting means)
28 Torque sensor

Claims (2)

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;
Idle stop control means for automatically stopping the drive source in response to a predetermined stop condition being satisfied during driving of the drive source;
A vehicle control device, comprising: prohibiting means for prohibiting the automatic stop of the drive source by the idle stop control means when a steering torque detected by the torque sensor before stopping is equal to or greater than a predetermined torque threshold. A wheel speed difference detecting means for detecting a wheel speed difference between the left wheel and the right wheel of the vehicle;
The prohibiting means is such that a steering torque detected by the torque sensor before stopping is equal to or greater than the torque threshold, and a wheel speed difference detected by the wheel speed difference detecting means is equal to or greater than a predetermined wheel speed difference threshold. 2. The vehicle control device according to claim 1, wherein automatic stop of the drive source by the idle stop control means is prohibited.

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