JP3061349B2 - Neutral switch fault detection circuit - Google Patents

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 an automobile. INDUSTRIAL APPLICATION This invention is utilized for the automatic control apparatus of a motor vehicle. INDUSTRIAL APPLICABILITY The present invention is applied to a slope start assist device and other devices that take in the control circuit that the transmission is neutral and execute a program operation. The present invention relates to a circuit that detects that neutral information of a transmission is not accurately recognized due to a mechanical or electrical cause and issues an alarm.

[0002]

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

For example, when the hill-start assist vehicle speed is substantially zero, the brake pedal is depressed, on condition that the transmission is in the neutral position, the brake pressure even brake pedal is released Then, the transmission is engaged in the starting gear, and the clutch pressure is detected to release the brake pressure. In this case, the information that the transmission is in the neutral position needs to be accurate as a control condition, and the binary information generated by the neutral switch is used.

[0004] The neutral switch is a component having a relatively simple mechanical structure, and a device for immediately detecting that the neutral switch has failed has not been known.

[0005]

When a neutral switch fails and its output information is erroneous, the control of a control circuit utilizing the same is disrupted.

The present invention has been made in such a background, and when an abnormality occurs in a neutral switch, the abnormality is reasonably detected before the abnormality affects control, and an alarm is issued. It is an object 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 a neutral position. SUMMARY OF THE INVENTION It is an object of the present invention to provide a device capable of detecting an abnormality of a neutral switch by processing software of a control circuit without adding or changing hardware.

[0007]

SUMMARY OF THE INVENTION The present invention detects an inaccurate recognition of information indicating that a transmission is in a neutral position and generates an alarm.
A binary signal generated by the switch is used as a reset input, a binary signal generated by operating the clutch pedal is used as a count input, and a counting circuit for sending out an alarm output when a preset count value n is reached is provided. Features . Preferably, the counting circuit is provided inside a control circuit that takes in the two binary signals generated by the neutral switch and executes a program operation, and the alarm output is optically displayed on a driver's seat. With this alarm output, the control circuit can execute a termination program, and the control can be converged to the safe side to terminate, that is, a so-called fail-safe type can be configured.

[0008]

The counting circuit inputs and counts a binary signal generated by detecting the operation of the clutch pedal. On the other hand, a binary signal from the neutral switch is used as a reset signal of the counting circuit. In general, the operation of the transmission and the operation of the clutch pedal are related, so there is no operation of the transmission,
It is determined that the repeated operation of the clutch pedal is not normal. Therefore, when this count value reaches a preset value n without being reset, an alarm output is sent out assuming that the neutral switch is in an abnormal state. For example, when adjusting the clutch pedal, the clutch pedal is operated many times without operating the transmission, and in this case, the alarm is unnecessary.
Therefore, it is appropriate to set the value of n to, for example, 5 ≦ n ≦ 15, and to set an upper limit.

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

As described above, when an abnormality occurs in the neutral switch, the abnormality is reasonably detected before affecting the control. Therefore, it is required that the transmission is in the neutral position by a simple circuit. Can be improved in the reliability of the control operation performed at the same time.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings.

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

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

FIG. 2 is a view for explaining a neutral region and a gear-in region of the transmission according to the first embodiment of the present invention. The neutral switch 1 is on when the shift lever is in a region shown by a broken line, and is off when the neutral region is deviated to the left or right and shifted into a gear-in region shown by a 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, the counting circuit 3 inputs the ON / OFF binary signal generated by the stroke sensor 2 every time the clutch pedal is depressed as the counting signal C. , "1, 2, 3,..., N". n is a predetermined setting value,
For example, “5”. On the other hand, when the shift lever is shifted to the neutral region shown in FIG. 2, a binary signal from the neutral switch 1 is sent to the counting circuit 3 as a reset signal R. When the reset signal R is input, the counting circuit 3 resets the count to zero, and thereafter repeats the same operation.

Since the clutch pedal is depressed in principle each 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 region. This is sent to the counting circuit 3 as a reset signal R. Therefore, the clutch operation does not reach the set value n.

It is not usually considered that the shift lever is not shifted to the neutral range until the set value n is exceeded. In such a case, an alarm output is sent to the alarm device 4 on the assumption that the neutral switch 1 is abnormal. Is done. The alarm device 4 turns on the alarm lamp 5 based on the alarm output, and optically displays and notifies that the abnormality has occurred in the neutral switch 1.

(Second Embodiment) FIG. 3 is a block diagram showing a configuration of a main part 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 includes an on state when the gear position of the transmission is in a neutral position and an off state when the gear is in. A binary signal from the neutral switch 1 is input as a reset signal R, and a binary signal generated by the stroke sensor 2 of the clutch pedal is input as a count signal C to execute a program operation. There is provided a counting means 6a which uses the output of the set count value n (for example, "5") of the depression of the clutch pedal as an alarm output. This alarm output is output from an alarm device 4 provided in the driver's seat as in the first embodiment.
Is displayed optically on the warning lamp 5 of the camera. In the case of the second embodiment, there is an advantage that the present embodiment can be implemented without requiring additional hardware.

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

The operation of the second embodiment of the present invention will now be described. FIG. 4 is a flowchart showing the flow of the control operation in the second embodiment of the present invention. The counting means 6a of the control circuit 6 inputs the count signal C generated by the stroke sensor 2, increases the count by "1" each time, and sets a preset count value n
The count up is continued until (for example, “5”).
During that time, a binary signal generated by the shift switch and the neutral switch 1 is transmitted, and the previous count value 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 region and 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 shift to the neutral area continues until the set value n is exceeded, the neutral
It is assumed that an abnormality has occurred in the switch 1 and the alarm device 4
The alarm device 4 turns on the alarm lamp 5 to optically display and report the occurrence of an abnormal condition.

It is convenient to set an upper limit for the set value n. That is, as described above, if the set value n is set to n = 5, if the clutch pedal is operated five times without operating the transmission, an alarm is generated as an abnormal condition. However, when the clutch pedal is adjusted, for example, when the air is released from the clutch, the clutch pedal is repeatedly operated without operating the transmission. In consideration of such a case, when the clutch pedal is operated five times, an alarm is generated once,
Further, the clutch pedal is operated repeatedly, for example, 15 times without operating the transmission without operating the clutch pedal.
When the pedal is operated, the alarm is extinguished at that time.

The upper limit of the set value n can be set so as to be effective only when the output of the vehicle speed sensor indicates zero vehicle speed. Generally, there is no need to adjust the clutch pedal while the vehicle is running. Even if performed, such an operation is abnormal.
Therefore, the upper limit of the set value n is made valid only when the output of the vehicle speed sensor indicates zero vehicle speed, and the alarm is extinguished when the upper limit of n is reached. 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. However, this is not limited to a so-called stroke sensor, and various types 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 according to the operation of the clutch pedal. Another example is an output from a sensor that detects the stroke of the clutch pedal as an analog signal. It utilizes a binary signal generated according to whether or not the detection output exceeds a certain threshold.

(Application Example) The control circuit 6 is a device that executes control that is performed on condition that the gear of the transmission is in the neutral position. Here, it is a device that performs slope start control. 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.

Here, the outline of the slope start assisting device will be described. When the vehicle speed is reduced to zero, the service brake switch 15 is depressed by the output of the vehicle speed sensor 11 when the service brake switch 15 is depressed. If it is on, the electromagnetic valve 16 is controlled to maintain the brake pressure supplied to the brake booster. 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 engaged in the starting gear (or reverse gear), and the clutch pedal is slowly released to reach the set position. Then, in accordance with the input from the stroke sensor 2, the solenoid valve 16 is controlled to release the brake pressure held until then. According to this control, when starting on a hill, the driver must brake and
It is not necessary to perform the operation of stepping on the accelerator pedal when the pedal is slammed, and a smooth hill start can be performed.

In this device, it is necessary to correctly detect that the starting gear or the reverse gear is set in the transmission. On the other hand, if the transmission is in the neutral position and the erroneous recognition is made and the hill start control is executed, the vehicle will slide down the hill. The present invention can be used in this device to confirm that the neutral switch 1 is sending accurate output information.

The device according to the invention can be used instead of or together with a neutral switch.
It can also be used for gear-in switches. The gear-in switch is a switch that outputs, as a binary signal, that the transmission has been operated and the gear has been engaged. That is, the neutral switch sends a binary signal indicating whether the transmission position is in the neutral position, whereas the gear-in switch indicates a binary signal indicating whether the transmission position is in the gear-engaging 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 engaged position. The undefined position where the transmission lever has been operated to leave the neutral position but the gear has not been fully engaged corresponds to this gap. The slope start assist device implemented by the applicant is designed to recognize this gap correctly and to perform control reliably. That is, when the position of the transmission is in this gap, the hill start 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 simultaneously with 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 the condition that the gear of the transmission is in the neutral position is reliably performed. And the reliability of the control operation can be improved.

[0031]

As described above, according to the present invention, when an abnormality occurs in a neutral switch, the abnormality is rationally detected and an alarm is generated and reported before the abnormality affects control. Can be. As a result, it is possible to improve the reliability of various controls executed on condition that the transmission is in the neutral position. This can be implemented by simply changing the software of the control circuit without adding or changing any hardware when configured with software.

[Brief description of the 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 illustrating a flow of a control operation according to a 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 assistance device.

[Explanation of symbols]

 DESCRIPTION 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)

(57) [Claims] 1. 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 alarm output is sent out when a preset count value n is reached. A fault detection circuit for a neutral switch, comprising a counting circuit. 2. The neutral switch failure detection circuit according to claim 1, wherein said counting circuit is provided inside a control circuit which takes in said two binary signals and executes a program operation. 3. The failure detection circuit for a neutral switch according to claim 1, wherein the alarm output is optically displayed on a driver's seat.