JPH0894496A - Failure detection circuit for neutral switch - Google Patents

Abstract

PURPOSE: To detect the occurrence of abnormality in a neutral switch before the control operation is effected thereby and to deliver an alarm. CONSTITUTION: A count circuit 3 counts binary ON/OFF signals delivered from the stroke sensor 2 for a clutch pedal and reset by a binary signal delivered from a neutral switch 1. When the count reaches a predetermined count (n) (5>=n>=15), an alarm is delivered to notify that the neutral switch 1 is abnormal. This constitution enhances the reliability of various control operations carried out on condition that the transmission is in the neutral position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a driving assistance device for automobiles. INDUSTRIAL APPLICABILITY The present invention is used for an automatic control device for an automobile. INDUSTRIAL APPLICABILITY The present invention is used in a device for executing a program operation by taking into account that a transmission is in a neutral condition in a control circuit, such as a slope start assist device. The present invention relates to a circuit that detects and alerts that neutral information of a transmission is not accurately recognized due to a mechanical or electrical cause.

[0002]

2. Description of the Related Art A neutral switch that is turned on in a neutral position of a transmission is widely used. This neutral switch has a structure for transmitting an on / off binary signal, and the binary signal is taken in and processed by a control circuit which executes a program operation.

For example, a hill start assist system brakes even when the brake pedal is released, provided that the brake pedal is depressed when the vehicle speed is substantially zero and the transmission has left the neutral position. It is controlled to hold the pressure, then the transmission is put into the starting gear, and it is detected that the clutch is engaged, and the brake pressure is released. In this case, the information that the transmission has left the neutral position needs to be accurate as a control condition, and the binary information generated by the neutral switch is used.

The neutral switch is a component having a relatively simple mechanical structure, and conventionally, there is no known device for immediately detecting an abnormality of the neutral switch.

[0005]

If the neat switch fails and the output information is incorrect, the control of the control circuit using it will be confused.

The present invention has been made against such a background. When an abnormality occurs in the neutral switch, the abnormality is reasonably detected and an alarm is given before the abnormality affects the control. The object is to provide a device for generating. An object of the present invention is to improve the reliability of a device that executes control on condition that the transmission is in the neutral position. An object of the present invention is to provide a device capable of detecting an abnormality of a neutral switch by modifying software of a control circuit without adding or changing hardware.

[0007]

SUMMARY OF THE INVENTION The present invention is to detect that the information indicating that the transmission is in the neutral position is not accurately recognized and issue an alarm.
A binary signal generated by the switch is used as a reset input, a binary signal generated by the operation of the clutch / pedal is used as a count input, and a counting circuit that outputs the preset count value n as an alarm output is provided. It is desirable that the counting circuit is provided inside a control circuit that executes the program operation by taking in the two binary signals generated by the neutral switch, and the alarm output is preferably optically displayed on a driver's seat. . With this alarm output, it is possible to configure a so-called fail-safe type in which the end program is executed by the control circuit and the control is converged to the safe end.

[0008]

The counting circuit inputs and counts the binary signal generated by detecting the operation of the clutch pedal. On the other hand, the binary signal from the neutral switch is used as the reset signal of this counting circuit. Generally, since the operation of the transmission and the operation of the clutch pedal are related, there is no operation of the transmission,
It is determined that the repeated operation of the clutch pedal is not normal. Therefore, when the count value reaches a preset value n without being reset, an alarm output is output as if the neutral switch is in an abnormal state. When adjusting the clutch pedal, the clutch pedal is operated a large number of times without operating the transmission, and in this case, the alarm is useless.
Therefore, it is appropriate that the value of n is set to 5 ≦ n ≦ 15 and an upper limit is set.

When the counter circuit incorporates the binary signal generated by the neutral switch and the binary signal generated by the stroke sensor as software inside the control circuit for executing the program operation, additional hardware is required. do not need. The alarm output is optically displayed on the display means provided in the driver's seat.

As described above, when an abnormality occurs in the neutral switch, the abnormality can be reasonably detected before it affects the control. Therefore, it is required that the transmission is in the neutral position with a simple circuit. It is possible to improve the reliability of the control operation performed in the above.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the arrangement of the essential parts of the first embodiment of the present invention.

The first embodiment of the present invention is a neutral switch 1 which is on when the gear position of the transmission is in neutral and is off when the gear position is in gear.
Is inputted as the reset signal R and the binary signal generated by the stroke sensor 2 of the clutch pedal is inputted as the counting signal C, and the predetermined count value n of the depression of the clutch pedal is inputted. A counting circuit 3 that outputs an alarm output is provided. The alarm output output from the counting circuit 3 is optically displayed on the alarm lamp 5 of the alarm device 4 provided in the driver's seat.

FIG. 2 is a diagram for explaining the neutral region and the gear-in region of the transmission according to the first embodiment of the present invention. The neutral switch 1 is in the on state when the shift lever is in the area indicated by the broken line, and is in the off state when the shift lever is shifted to the left or right from the neutral area to the gear-in area indicated by the solid line. This on / off binary signal is input to the counting circuit 3 as a reset signal.

In the first embodiment of the present invention thus constructed, the counting circuit 3 inputs as the counting signal C an on / off binary signal generated by the stroke sensor 2 each time the clutch pedal is depressed. , "1, 2, 3, ..., N". n is a preset value,
For example, "5". On the other hand, when the shift lever is shifted to the neutral range shown in FIG. 2, the binary signal from the neutral switch 1 is sent to the counting circuit 3 as the reset signal R. When the counter circuit 3 receives the reset signal R, it resets the count count to zero and repeats the same operation thereafter.

Since the clutch pedal is stepped on every time the gear position of the transmission becomes neutral, if the neutral switch 1 is normal, a binary signal is generated when the shift lever is shifted to the neutral range. Then, the reset signal R is sent to the counting circuit 3. Therefore, the clutch operation does not reach the set value n.

In the case where the shift lever is not shifted to the neutral range until the set value n is exceeded, it is not normally considered. In such a case, an alarm output is sent to the alarm device 4 as an abnormality of the neutral switch 1. To be done. Based on this alarm output, the alarm device 4 turns on the alarm lamp 5 to optically display and inform that the neutral switch 1 is abnormal.

(Second Embodiment) FIG. 3 is a block diagram showing the arrangement of the essential parts of a second embodiment of the present invention.

In the second embodiment of the present invention, a control circuit 6 for executing a program control relating to the running of an automobile is provided with an ON state when the gear position of the transmission is in neutral and an OFF state when the gear is in gear. The binary signal from the neutral switch 1 is input as the reset signal R, and the binary signal generated by the stroke sensor 2 of the clutch pedal is input as the count signal C to execute the calculation of the program in advance. The counting means 6a is provided which outputs an output of the set count value n (for example, "5") of depression of the clutch pedal which has been set. This alarm output is the alarm device 4 provided in the driver's seat as in the first embodiment.
It is optically displayed on the alarm lamp 5 of. In the case of the second embodiment, there is an advantage that it can be carried out without requiring additional hardware.

The operation of the second embodiment of the present invention thus constructed will be described. FIG. 4 is a flow chart showing the flow of control operation in the second embodiment of the present invention.

The counting means 6a of the control circuit 6 receives the count signal R generated by the stroke sensor 2, increments the count by "1" each time, and sets a preset count value n (for example, "5"). Continue to count up until. During that time, gear shifting is performed and the neutral switch 1
Is transmitted, and the count value so far is reset to zero. If the neutral switch 1 is normal, a binary signal is generated each time the shift lever is shifted to the neutral range, and this binary signal is sent to the counting means 6a as the reset signal R so that the clutch operation reaches the set value n. Nothing happens and the same control operation is repeated.

If the state of not being shifted to the neutral region continues until the set value n is exceeded, the neutral
Alarm device 4 as if the switch 1 is abnormal
An alarm output is sent to the alarm device 4, and the alarm device 4 illuminates the alarm lamp 5 to optically display the occurrence of an abnormal state to notify it.

It is convenient to set an upper limit on the set value n. That is, if the set value n is set to n = 5 as described above, if the clutch pedal is operated 5 times without operating the transmission, this is an alarm and an alarm is issued. However, when the clutch pedal is adjusted, for example, when the air bleeding operation of the clutch is performed, the clutch pedal is repeatedly operated without the operation of the transmission. In consideration of such a case, when the clutch pedal is operated 5 times, an alarm is issued once,
By repeatedly operating the clutch pedal, the clutch pedal can be operated 15 times without operating the transmission.
The alarm should disappear when the pedal is operated.

The upper limit of the set value n can be set to be effective only when the vehicle speed sensor output indicates zero vehicle speed. Generally, the clutch pedal is not adjusted while the vehicle is traveling. Even if it is done, such operation is abnormal.
Therefore, the vehicle speed sensor output is also taken in, and the upper limit value of the set value n is made effective only when the vehicle speed sensor output indicates zero vehicle speed, and when the upper limit value of n is reached, the alarm is dismissed. It is desirable to set to.

In the above example, the clutch / stroke sensor is used as the binary signal generated by the operation of the clutch / pedal, but this is not limited to the so-called stroke sensor, but various kinds of sensors are generated. Binary signals can be used. One example is an on / off switch that is provided on the clutch pedal and responds to the operation of the clutch pedal, and another example is the output of a sensor that detects the stroke of the clutch pedal as an analog signal. It utilizes a binary signal generated depending on whether or not the detection output exceeds a certain threshold value.

(Application example) The control circuit 6 is a device for executing the control under the condition that the gear of the transmission is in the neutral position. Here, it is a device for controlling the start of a slope. FIG. 5 is a block diagram showing a configuration example of a main part when the embodiment of the present invention is applied to a slope start control device.

The hill start assisting device will be briefly described. In the hill start assisting device, when the vehicle speed becomes zero due to the output of the vehicle speed sensor 11, the brake pedal is depressed and the service brake switch 15 is turned on. If it is on, the solenoid valve 16 is controlled to bring the brake pressure supplied to the brake booster into a holding state. This brake pressure is maintained even when the brake pedal is released. Next, it is detected by the neutral switch 1 and the gear-in switch 13 that the transmission has been operated and the transmission has been put into the start gear (or reverse gear), and the clutch pedal is gently released to reach the set position. Then, according to the input from the stroke sensor 2, the solenoid valve 16 is controlled to release the brake pressure held up to that point. With this control, the driver can
It is no longer necessary to move the accelerator pedal while pushing the pedal, and a smooth hill start can be performed.

In this device, it is necessary to correctly detect whether the transmission is set to the start gear or the reverse gear. However, if the transmission is in the neutral position and this is mistakenly recognized and the slope start control is executed, the vehicle will slide down the slope. The present invention can be utilized in this device to verify that the neutral switch 1 is delivering accurate output information.

The device of the present invention may be used in place of the neutral switch or together with the neutral switch.
It can also be used as a gear-in switch. The gear-in switch is a switch that outputs, as a binary signal, that the transmission has been operated and the gear has been turned on. That is, the neutral switch sends a binary signal indicating whether the transmission position is in the neutral position, whereas the gear-in switch outputs a binary signal indicating whether the transmission position is in the gear closing position. Send a signal. Generally this is considered a simple contradictory logic, but in actual hardware there is a small gap between the neutral position and the gear engaged position. This gap corresponds to an indeterminate position where the transmission lever has been operated to leave the neutral position but the gear has not been fully engaged. The hill start assist device implemented by the applicant is designed to correctly recognize this gap and ensure control. That is, when the position of the transmission is in this gap, the slope starting assist device is designed not to release the brake pressure. Therefore, it is possible to apply the device of the present invention to the output of the gear-in switch instead of the neutral switch, or to apply the device of the present invention to the gear-in switch at the same time as the neutral switch,
Similarly, there is an effect that the reliability of control can be improved.

As described above, the hill start assisting operation is performed by the control circuit 6
By providing the control circuit 6 with the counting means 6a described in the second embodiment, the hill start control that is performed on condition that the gear of the transmission is in the neutral position is reliably performed. Therefore, the reliability of the control operation can be improved.

[0031]

As described above, according to the present invention, when an abnormality occurs in the neutral switch, the abnormality is reasonably detected and an alarm is generated before the influence on the control is given. You can As a result, the reliability of various controls executed on condition that the transmission is in the neutral position can be improved. This can be implemented by only changing the software of the control circuit without adding or changing the hardware when it is configured by software.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a neutral region and a gear-in region of the transmission according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a main part of a second embodiment of the present invention.

FIG. 4 is a flowchart showing a flow of control operation in the second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration example of a main part when the embodiment of the present invention is applied to a slope start assist device.

[Explanation of symbols]

 1 Neutral Switch 2 Stroke Sensor 3 Counting Circuit 4 Alarm Device 5 Alarm Lamp 6 Control Circuit 6a Counting Means 7 Alarm Buzzer 11 Vehicle Speed Sensor 12 Parking Brake Switch 13 Gear In Switch 14 Gradient Sensor 15 Service Brake Switch 16 Solenoid Valve

Claims (3)

[Claims] 1. A counting method in which a binary signal generated by a neutral switch is used as a reset input, a binary signal generated by operating a clutch pedal is used as a count input, and an output of a preset count value n is used as an alarm output. Neutral switch failure detection circuit characterized by having a circuit. 2. The fault detection circuit for a neutral switch according to claim 1, wherein the counting circuit is provided inside a control circuit that takes in the two binary signals and executes a program operation. 3. The neutral switch failure detection circuit according to claim 1, wherein the alarm output is optically displayed on a driver's seat.