JPH0891183A - Up-slope start assisting device - Google Patents

Abstract

PURPOSE: To temporarily hold braking pressure even if a brake pedal is released when a clutch is stepped by containing a means in a control circuit so as to prohibit sending-out of control output when the acceleration information shows deceleration when horizontal directional acceleration information is taken in. CONSTITUTION: When car speed is zero, horizontal directional acceleration information α is taken in from an acceleration sensor 8, and whether or not the acceleration information(X shows deceleration (α<0) is judged. When it shows the deceleration, it is judged that true speed is not zero, and sending-out of a control signal to a solenoid valve 1 is prohibited, and sloping road departure assisting operation is stopped. When it does not show the deceleration, since the car speed is reliably zero, when a stroke of a clutch pedal 12 exceeds a prescribed value, the control signal is sent out to the solenoid valve 1, and the sloping road departure assisting operation is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a vehicle driving assistance device. SUMMARY OF THE INVENTION The present invention is an improvement of a slope start assist device that temporarily holds the braking pressure even if the brake pedal is released when the clutch is depressed when the vehicle speed reaches zero due to the application of a braking pressure above a predetermined level. Regarding INDUSTRIAL APPLICABILITY The present invention is applied to an automobile equipped with a clutch and a manual shift transmission, and is not applied to an automatic vehicle having no clutch pedal.

[0002]

2. Description of the Related Art A driving operation for starting an uphill road in which an automobile stopped in the middle of an uphill road is started in an uphill direction, in which a brake pedal is depressed and a clutch pedal is depressed to start a transmission (or a reverse gear). ) Is set and the clutch pedal is gently pulled in the shallower stepping direction, and when the clutch is in the half-clutch state, the brake pedal is released and the accelerator pedal is depressed. The slope start assist device is a driving assist device that automatically executes this. In other words, when the vehicle decelerates when the vehicle decelerates and the vehicle speed reaches zero (or almost zero), if the clutch pedal is depressed beyond a predetermined value, the slope start assist device releases the brake pedal. Is also controlled to automatically maintain the braking pressure. further,
When the clutch pedal on which the transmission has been set and stepped on is released to the set position, the holding state of the braking pressure is automatically released.

This device takes in a solenoid valve connected so as to maintain a braking pressure according to control even when the brake pedal is released, a vehicle speed information and a stroke information of a clutch pedal, and electrically operates this solenoid valve. And a program control circuit for controlling. When equipped with this device, the driver can hold the vehicle in a stopped state even if the driver releases the brake pedal without applying side brakes. You can Further, when driving on a road in a congested state, it is not necessary to continue to press the brake pedal for a long time or repeatedly operate the side brake, so that the driver's fatigue can be reduced.

Such a slope starting assist device is disclosed in Japanese Patent Laid-Open No.
No. 4-60456, JP-A-64-60457, and others. This device has come into widespread use in freight vehicles whose operating conditions change depending on the weight of the vehicle. The applicant of the present application is equipped with an acceleration sensor (or a gravity sensor), and the acceleration information from this acceleration sensor is taken into this hill start assist device, and when the slope is steep, improvements are made such as controlling the operation, etc. (Japanese Patent Application No. 5-188470, unpublished at the time of filing this application). Further, as a technique for improving control by taking in acceleration information in addition to vehicle speed information, an anti-skid brake device, not a slope start assist device, is disclosed in Japanese Patent Laid-Open No. 63-171.
No. 61 is disclosed.

[0005]

The inventor of the present application has repeatedly tested the slope starting assist device and has found that the operation is defective when the wheel and the road surface become slippery. In other words, if this slope start assist device is operated on a slippery road surface such as snowy or frozen road surface, when braking pressure is applied to the wheels to stop the vehicle, slippage occurs between the wheels and the road surface. May be. At this time, the rotation of the wheels is stopped, a so-called locked state is set, and the vehicle speed information sent from the vehicle speed sensor shows substantially zero. Then,
The control circuit of the slope start assist device controls so that the braking pressure is maintained even when the driver releases the brake pedal because the vehicle speed information becomes zero. In other words, when the vehicle is slipping on the road surface, braking pressure is maintained and wheel rotation is prohibited, so even if the driver recognizes the slip condition and loosens the brake, it is possible to continue the slip condition even more. become.

The present invention has been made against such a background, and it is an object of the present invention to provide a hill start assisting device in which the braking pressure is not maintained against the driver's intention during traveling on a slippery road surface. With the goal. SUMMARY OF THE INVENTION It is an object of the present invention to provide a slope start assist device that does not maintain braking pressure even when wheel rotation stops when the actual vehicle speed is not zero. SUMMARY OF THE INVENTION It is an object of the present invention to provide a slope starting assistance device in which braking pressure is not maintained when a slip condition occurs between a wheel and a road surface. It is another object of the present invention to provide a slope start assist device that can detect that the vehicle is in a slipping state even when a failure occurs in which the output of the acceleration sensor is fixed to zero. .

[0007]

SUMMARY OF THE INVENTION According to the present invention, when the actual vehicle speed is not zero even when the wheel rotation is stopped due to the slip between the wheel and the road surface, the braking pressure is prohibited from being held and the vehicle travels. The solenoid valve is connected so as to maintain the braking pressure according to the control even when the brake pedal is released, and the vehicle speed information, the brake pedal operation information and the clutch pedal stroke information are fetched. A control circuit for controlling the valve, wherein the control circuit controls the solenoid valve to hold the braking pressure when the brake pedal is depressed and the vehicle speed becomes zero and the stroke of the clutch pedal is depressed deeper than a predetermined value. In the slope start assist device including means for transmitting an output, the control circuit takes in horizontal acceleration information (α) and the acceleration information indicates deceleration (α <0. ) Sometimes, a means for inhibiting the transmission of the control output is included.

The control circuit includes means for calculating a time derivative (dV / dt) of the vehicle speed information (V), and when the time derivative value exceeds a predetermined value to indicate deceleration (dV / dt <
α ₀ <0), the means for prohibiting the transmission of the control output and the setting information of the transmission gear are taken in together, and the stroke of the clutch pedal is set to the set value during the transmission of the control output with the transmission gear set. And a means for stopping the control output and causing the solenoid valve to release the braking pressure holding state when there is a change in the shallower stroke over. The output information of the gear-in switch that detects that the reverse gear is set is desirable.

[0009]

[Operation] When the test is repeated on a slippery road surface, when the wheels are locked and slipping, even if the wheel rotation stops and the vehicle speed information is displayed as zero,
It was found that a small deceleration acceleration was detected in the vehicle.

Therefore, for example, when a small acceleration is detected in the deceleration direction by the acceleration sensor, the actual vehicle speed is not zero even if the vehicle speed information is zero, and in this case the braking pressure is not held. To control.

On the other hand, instead of relying on the acceleration information from the acceleration sensor, the time derivative (dV /
The acceleration can be obtained by calculating dt). It is rational to use the acceleration obtained by this calculation together. However, the acceleration resulting from this calculation becomes inaccurate with the passage of time after the slip condition occurs and the vehicle speed information is fixed at zero, and becomes useless with the passage of time, so that the vehicle slips on a very slippery surface for a long time. It is not suitable for detecting a small deceleration that occurs as a result.

When a sensitive acceleration sensor is mounted on a vehicle in order to detect a small acceleration, the sensitive acceleration sensor may have a failure in which its output value is fixed to zero for some reason. At this time, the time differential value of the vehicle speed information can be adopted. As a result of various tests on the acceleration based on the time differential value, when there is a deceleration exceeding a predetermined value (for example, a predetermined value set to 0.1 G to 1 G, 0.4 G as an example),
Even if there is no input of deceleration acceleration from the acceleration sensor,
It is advisable to prohibit holding braking pressure. The time derivative of the velocity information is of a nature that can be realized by software calculation, and does not require any additional hardware.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the main part of the embodiment of the present invention.

In the embodiment of the present invention, the solenoid valve 1 connected so as to maintain the braking pressure according to the control even if the brake pedal 11 is released, the vehicle speed sensor 2 for detecting the vehicle speed, and the operation of the brake pedal. The stop lamp switch 3 for detecting, the clutch stroke sensor 4 for detecting the stroke of the clutch pedal 12, the hydraulic sensor 5 for detecting the hydraulic pressure value of the hydraulic circuit of the clutch, and the position of the vehicle speed lever are in neutral. A neutral switch 7 or a gear-in switch 9 for detecting that the transmission is set to a start gear or a reverse gear, an acceleration sensor 8 for detecting the acceleration of the vehicle, a vehicle speed sensor 2, a stop lamp switch 3, a clutch stroke. .Sensor 4, oil pressure sensor 5, neutral switch 7 or gear-in switch And program control circuit 10 for controlling the solenoid valve 1 receives the output from the acceleration sensor 8
And an operation panel 21 for inputting an operation to the program control circuit 10, and an alarm when the output of the acceleration sensor 8 exceeds a predetermined value while the brake pressure is being maintained on a downhill and when a failure occurs. Alarm device 22
And are provided. The alarm device 22 is provided with an alarm buzzer 23 that sounds an alarm and an alarm lamp 24 that lights up to generate an alarm.

Further, the program control circuit 10 has a control output for causing the solenoid valve 1 to hold the braking pressure when the brake pedal is depressed and the vehicle speed becomes zero and the stroke of the clutch pedal 12 is depressed deeper than a predetermined value. As a feature of the present invention, means for sending out the horizontal direction acceleration information (α) from the acceleration sensor 8 and means for inhibiting the sending of the control output when the acceleration information indicates deceleration (α <0). , Means for calculating the time derivative (dV / dt) of the vehicle speed information (V) from the vehicle speed sensor 2, and (dV / dt) when the time derivative value exceeds a predetermined value to indicate deceleration.
<Α ₀ <0), means for prohibiting the transmission of the control output,
The stroke information of the clutch pedal 12 is sent from the gear-in switch 9 together with the setting information of the transmission gear indicating whether the transmission is set to the forward gear or the reverse gear, and the control output is sent while the transmission gear is set. Means for stopping the control output and causing the solenoid valve 1 to release the braking pressure holding state when the value exceeds the set value and changes in the shallow step direction.

Next, the operation of the embodiment of the present invention thus constructed will be described.

First, a description will be given of a slope start assisting operation which is performed during normal traveling. FIG. 2 is a flow chart showing the flow of the brake holding operation in the embodiment of the present invention, and FIG. 3 is a flow chart showing the flow of the brake release operation in the embodiment of the present invention.

The brake holding operation by the program control circuit 10 is as shown in FIG.
Takes the output from the stop lamp switch 3 and determines whether or not the brake pedal is depressed.
If the brake pedal is not depressed, it means that the vehicle is not stopped due to braking, so the sending of the control signal to the solenoid valve 1 is prohibited and the assisting operation for starting the slope is stopped. When the brake pedal is depressed, the output from the vehicle speed sensor 2 is fetched to determine whether the vehicle speed is zero. If the vehicle speed is not zero, the vehicle is running, so the sending of the control signal to the solenoid valve 1 is prohibited and the auxiliary operation for starting the slope is stopped.

When the vehicle speed is zero, the output from the acceleration sensor 8 is taken in and it is determined whether or not the current output of the acceleration sensor 8 exceeds the set predetermined value S. When the output of the acceleration sensor 8 exceeds the predetermined value S, it is determined that the vehicle is not stopped and the control signal is not sent to the solenoid valve 1 to stop the auxiliary operation. If it does not exceed the predetermined value S, it is determined that the vehicle is in a stopped state, and it is determined whether or not the stroke of the clutch exceeds the predetermined value. If it exceeds the predetermined value, a control signal is sent to the solenoid valve 1, The valve 1 is driven to operate the brake valve 13 to execute a slope start assisting operation. If it does not exceed the predetermined value, the control signal transmission to the solenoid valve 1 is prohibited and the execution of the auxiliary operation is stopped.

Next, the brake release operation performed during normal traveling will be described with reference to FIG.

When the vehicle is in a brake holding state on a slope, the clutch stroke sensor 4 and the neutral
The output from the switch 7 or the gear-in switch 9 is taken in and it is determined whether or not the clutch pedal 12 has been depressed and the gear has been set to the forward drive position (low or second) or the reverse position.

When the clutch pedal 12 is stepped on and the gear is set to the starting state, it is judged from the output of the clutch stroke sensor 4 whether or not the stroke has become a predetermined stroke or less. When the stroke is equal to or less than the predetermined stroke, it is assumed that the vehicle is started, and the sending of the control signal to the solenoid valve 1 is prohibited and the brake is released. If the gear is not set to the start state or the depression amount of the clutch pedal 12 is equal to or more than the predetermined stroke,
The control signal is continuously sent to the solenoid valve 1 to maintain the brake holding state.

The initial value of the depression stroke value of the clutch pedal 12 for releasing the brake can be arbitrarily set in accordance with the driver's preference and the change due to the wear of the clutch by the operation input from the operation panel 21. The value of the set stroke of the clutch pedal 12 is held until it is reset. If the depression stroke of the clutch pedal 12 exceeds the set reference value, the starting assistance operation is continued.

As described above, when the vehicle starts on a slope, the brake holding and brake releasing operations are automatically performed according to the situation at that time, but the vehicle is stopped when the road surface is slippery. If braking pressure is applied to the wheels in an attempt to force the wheels to slip, a slip state may occur between the wheels and the road surface. When the slip state occurs, the rotation of the wheels is stopped even though the actual vehicle speed is not zero, so the vehicle speed information sent from the vehicle speed sensor 2 indicates zero, and the driver releases the brake pedal 11. Also, the braking pressure is held, and the slip state continues, which causes a problem.

According to the present invention, even if the output value of the vehicle speed sensor 2 is zero, the fact that the vehicle is traveling is detected by the output from the acceleration sensor 8 and the braking pressure is not maintained. . Here, the control operation will be described. FIG. 4 is a flow chart showing the flow of the brake holding operation due to the change in acceleration in the embodiment of the present invention.

First, the program control circuit 10 takes in the output from the stop lamp switch 3 and determines whether or not the brake pedal is depressed. If the brake pedal 11 is not depressed, the vehicle is not braked and is not stopped. Therefore, the control signal transmission to the solenoid valve 1 is prohibited and the slope start assist operation is stopped. When the brake pedal 11 is stepped on, the output from the vehicle speed sensor 2 is taken in to determine whether the vehicle speed is zero. If the vehicle speed is not zero, the vehicle is in a running state, so sending of a control signal to the solenoid valve 1 is prohibited and the hill start assisting operation is stopped.

When the vehicle speed is zero, horizontal acceleration information (α) is fetched from the acceleration sensor 8 and it is determined whether or not the acceleration information (α) indicates deceleration (α <0). If deceleration is indicated, it is assumed that the true speed is not zero, and the sending of the control signal to the solenoid valve 1 is prohibited and the slope start assist operation is stopped. If deceleration is not indicated, the vehicle speed is surely zero, so if the stroke of the clutch pedal 12 exceeds a predetermined value, a control signal is sent to the solenoid valve 1 to execute the slope start assist operation.

For deceleration of the vehicle, the vehicle speed information (V) is fetched from the vehicle speed sensor 2, the time derivative (dV / dt) of this vehicle speed information (V) is calculated, and the time derivative value exceeds the predetermined value to decelerate. In other words, it is also confirmed by whether or not dV / dt <α ₀ <0 when α ₀ is set to a predetermined value. Prohibit

Next, the brake releasing operation in the embodiment of the present invention will be described. The control operation is performed according to the flow shown in FIG. 3, but since the gear-in switch 9 is provided in the present embodiment, the program control circuit 10
After confirming that the clutch pedal 12 has been stepped on for a predetermined stroke or longer, the output from the gear-in switch 9 is taken in to determine whether the transmission is set to the forward gear or the reverse gear, and the transmission gear is set to the forward gear. Alternatively, if the control signal is sent to the solenoid valve 1 while the reverse gear is set, it is determined whether or not the stroke of the clutch pedal 12 has exceeded the set value and changed in the shallow stroke direction, When the vehicle has changed to a shallow direction, it is determined that the vehicle has started, and the control signal output to the solenoid valve 1 is stopped to release the braking pressure holding state.

The gear-in switch 9 is attached to the upper cover 16 together with the neutral switch 7 as shown in FIG.
If, for example, the shift shaft 17 is turned to the left side in FIG. 6, the neutral switch 15 will be in the OFF state as shown in FIG. 7 at the position P ₁ moved by the angle θ _1, but the gear-in switch 9 is still in the off position. In the OFF state,
Further, when the position of Q _{1 in} FIG. 6 rotated by the angle Δθ is reached, the gear-in switch 9 is turned on. The transmission shift shaft 17 has an angle θ to the right.
₁ neutral switch 7 likewise the position of P ₂ when turned is turned OFF, gear-switches 9
6 is in the OFF state and is further rotated by the angle Δθ in FIG.
It is configured to be in the ON state when the position of the upper Q ₂ is reached.

This is because the transmission shift shaft 17 is turned to either the left or right, and the neutral
Switch 7 is turned off and gear-in switch 9
The range of angle Δθ until ON is ON, OFF
Therefore, the neutral switch 7 is turned on and off and the gear-in switch 9 is turned on and off at an angle Δθ.

[0032]

As described above, according to the present invention, a slip state occurs between a wheel and a road surface while traveling on a slippery road surface, and the wheel speed is not zero even though the actual vehicle speed is not zero. It is possible to prevent the braking force from being retained against the driver's will by stopping the rotation of the vehicle, and further, in the event of a failure such that the output of the acceleration sensor is fixed at zero value. Also, since it is possible to detect that the vehicle is in a slipping state, it is possible to improve the drivability on a slippery road surface.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a brake holding operation by a program control circuit in the embodiment of the present invention.

FIG. 3 is a flowchart showing a flow of a brake release operation by the program control circuit in the embodiment of the present invention.

FIG. 4 is a flowchart showing a flow of a brake holding operation due to a change in acceleration in the embodiment of the present invention.

FIG. 5 is a diagram showing a mounting state of a gear-in sensor and a neutral switch to a transmission according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining the positions of neutral and gear-in due to rotation of a transmission shift shaft.

FIG. 7 is a diagram illustrating a neutral region and a gear-in region of the transmission according to the embodiment of the present invention.

[Explanation of symbols]

 1 Solenoid Valve 2 Vehicle Speed Sensor 3 Stop Lamp Switch 4 Clutch Stroke Sensor 5 Oil Pressure Sensor 7 Neutral Switch 8 Accelerometer 9 Gear In Switch 10 Program Control Circuit 11 Brake Pedal 12 Clutch Pedal 13 Brake Valve 16 Upper Cover 17 Transmission Shift・ Shaft 21 Operation panel 22 Alarm device 23 Alarm buzzer 24 Alarm lamp

Claims (4)

[Claims] 1. A solenoid valve connected so as to maintain braking pressure according to control even when the brake pedal is released, and a solenoid valve that takes in vehicle speed information, brake pedal operation information, and clutch pedal stroke information. And a control circuit for controlling, wherein the control circuit outputs a control output that causes the solenoid valve to hold the braking pressure when the brake pedal is depressed and the vehicle speed becomes zero and the stroke of the clutch pedal is depressed deeper than a predetermined value. In the slope start assist device provided with means for sending out, the control circuit takes in horizontal direction acceleration information (α), and when the acceleration information indicates deceleration (α <0), means for prohibiting the sending of the control output is provided. Slope start assist device characterized by including. 2. The control circuit includes means for calculating a time derivative (dV / dt) of vehicle speed information (V), and when the time derivative value exceeds a predetermined value to indicate deceleration (dV / dt).
<Α ₀ <0), The slope start assisting device according to claim 1, further comprising means for prohibiting transmission of the control output. 3. The direction in which the stroke of the clutch pedal exceeds the set value and the step margin is shallow while the control circuit also fetches the setting information of the transmission gear and outputs the control output in the state where the transmission gear is set. 3. The slope start assist device according to claim 1 or 2, further comprising means for stopping the control output and causing the solenoid valve to release the braking pressure holding state when the control output changes. 4. The slope start assist device according to claim 3, wherein the setting information of the shift gear is output information of a gear-in switch that detects that the transmission is set to a start gear or a reverse gear.