JPS6116138A - Automatic vehicle speed control device - Google Patents

Abstract

PURPOSE:To make it possible to facilitate the determination of systematic malfunction of an automatic vehicle speed control, by providing a ratch mechanism for holding a switch section in its inoperative condition upon malfunction of a controller and for energizing an external display mechanism. CONSTITUTION:When any abnormality is generated in a microcomputer 6, it is transmitted to a ratch circuit 42 through a timer synchroprogram 40 and a hard timer circit 41. This ratch circuit 42 holds the microcomputer in its deenergized condition in accordance with the generation of abnormality of the microcomputer 6 to cancel a system, and makes a relay drive circuit 43 inoperative to pre- vent a relay 25 from being turned on. Therefore, the operation of an actuator 10 comes to a stop, and simultaneously, an external display mechanism 46 is energized to hold LEDs as light emitting elements in an LED display device 45 in their turn-on condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic vehicle speed control device used to automatically control the traveling speed of a vehicle to a certain set value.

(Prior Art) As a conventional automatic vehicle speed control device, there is one having the configuration shown in FIG. 1 and FIG. 2, for example.

In FIG. 1, a vehicle speed sensor 1 generates a signal proportional to the actual vehicle speed, and a command switch 2 generates a cruise command signal, and the command switch 2 includes a set switch and a resume switch. Outputs from the vehicle speed sensor 1 and command switch 2 are input to a microcomputer 6 also within the controller 3 via interfaces 4 and 5 within the controller 3, respectively. This microcomputer 6 has a built-in vehicle speed storage section that stores the vehicle speed when the command switch 2 is operated.

Further, 10 is an actuator, and as shown in FIG.
, a safety valve 12 , and a vacuum valve 13 , one end of the vent valve 11 and the safety valve 12 are open to the atmosphere, and the vacuum valve 1
One end of 3 is connected to the intake manifold (negative pressure source). The other end of each valve 11, 12.13 communicates with a negative pressure chamber 17 formed by the casing 15 and one side of the diaphragm 16 (right side in FIG. One end of the control wire 18 is connected to the side (left side in FIG. 2), and the other end of the control wire 18 is connected to the throttle valve shaft 12.

Furthermore, 21 is located in the controller 3 and controls the vent valve 11 on and off according to the output from the microcomputer 6, and 22 is also located in the controller 3 and controls the vent valve 11 according to the output from the microcomputer 6. A vacuum valve switching unit 23, which controls the vacuum valve 13 on and off in response, is also located in the controller 3 and turns on and off the power supply to the actuator 10 according to the output from the microcomputer 7. This is a switching part for the Kuchiyu factory, and in this case, the power supply is turned on and off by the relay 2 consisting of the relay coil 25 & and relay switch 25b.
5.

Further, 27 is a brake switch, 28 is a brake lamp, and a signal for canceling the system when the brake is operated is inputted to the microcomputer 6 via the interface 22 in the controller 3.

Furthermore, 31 is a constant voltage circuit, 32 is a reset circuit, 33
is a power supply, and 34 is a main switch for the control device.

Next, to explain the operation of the automatic vehicle speed control device having such a configuration, including FIG. 3, first, the vehicle speed sensor 1
generates a pulse proportional to the actual vehicle speed, inputs this pulse signal into the microcomputer 6 of the controller 3, samples it within a fixed period, and always makes the microcomputer 6 recognize the number of pulses proportional to the vehicle speed. . In this state, when a set signal is sent from the command switch 2 at time t1, for example, the microcomputer 6 stores the number of pulses corresponding to the vehicle speed at that time in the vehicle speed storage section, and from then on, the detected actual vehicle speed is A command is sent to the actuator 10 so that the corresponding number of pulses becomes equal to the stored pulse number (i.e., the stored vehicle speed), and the vent valve switching unit 21
and vent valves 11 and 7 < vacuum valve 1 through vacuum valve switching unit 22 respectively.
Actuator 1 by controlling on/off of 3
For example, at time t2 when the actual vehicle speed becomes higher than the memorized vehicle speed, the vent valve 11 is controlled by the operation of the vent valve switching section 21 controlled by the microcomputer 6. is turned off to introduce atmospheric air into the negative pressure chamber 17, thereby slightly rotating the throttle valve shaft 12 in the valve closing direction and reducing the vehicle speed. On the other hand, at time t3 when the actual vehicle speed becomes smaller than the memorized vehicle speed, the vacuum valve 13 is turned on by the operation of the vacuum valve switching section 22 controlled by the microcomputer 6 to create negative pressure in the negative pressure chamber 17. This causes the throttle valve shaft 12 to rotate slightly in the valve opening direction, thereby increasing the vehicle speed.

By repeating this operation, the vehicle speed is controlled to be constant. At this time, power is supplied to the actuator 10 via the relay 25.

However, in such a conventional vehicle speed automatic control device, even if there is a malfunction in the system, it is difficult to determine from outside the controller 6 whether the system malfunction is caused by a malfunction within the controller 3 or not. The problem was that it couldn't be done.

(Purpose of the Invention) This invention was made by focusing on the above-mentioned conventional problems, and in the unlikely event that there is a malfunction in the system of the automatic vehicle speed control device, the system malfunction is caused by a malfunction inside the controller. The purpose of this invention is to make it possible to determine from outside the controller whether or not the controller exists.

(Structure of the Invention) The present invention includes a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, a command switch that generates a cruise command signal, a vehicle speed storage unit that stores the vehicle speed when the command switch is operated, and a throttle valve. An automatic vehicle speed control device comprising an actuator to drive, a controller that sends a command to the actuator in response to a difference between the actual vehicle speed and the stored vehicle speed, and a switching unit that turns on and off power supply to the actuator, A latch circuit is provided that holds the switching section in an inoperative state and activates an external display mechanism when the controller malfunctions, so that when the system malfunctions, it can be determined whether or not the system malfunction is a malfunction inside the controller. A feature is that the judgment can be made from outside the controller.

(Embodiment) FIG. 4 is a diagram showing an embodiment of the present invention, and the same parts as those shown in FIG. 1 are denoted by the same reference numerals, and their explanation will be omitted. In the configuration shown in FIG. 4, 40 is a timer sync program in the microcomputer 6;
1 is a hard timer circuit connected to the timer sync program 40, 42 is a latch circuit connected to the hard timer circuit 41, 43 is a relay drive circuit connected to the latch circuit 42, and 44 is an external circuit connected to the latch circuit 42. This external display mechanism 44 includes a light emitting element such as an LED display device 45 and another external display device 46 .

In such a configuration, if an abnormality should occur in the microcomputer 6, this abnormality will be detected by the timer sync program 40. The signal is transmitted to the latch circuit 42 via the hard timer circuit 41, and the latch circuit 42 holds the output of the microcomputer 6 in an OFF state when an abnormality occurs in the microcomputer 6 to cancel the system. This latch circuit 42
The relay drive circuit 43 connected to the relay drive circuit 43 is put in an inoperable state so that the relay 25 is not turned on, and the operation of the actuator 10 is stopped.At the same time, the external display mechanism 44 is operated, and for example, the LED of the LED display device 45 is activated as a light emitting element.
Leave it lit.

FIG. 5 is a diagram showing a specific example of a configuration mainly including the latch circuit 42, in which the hard timer circuit 41 has a resistor R
,,R2, and a capacitor C, and the latch circuit 42 is composed of an arithmetic element (NOR), 02, and a resistor R3.
, R4, Rs, and a capacitor C2.

In a normal operating state, the voltage of the capacitor C1 in the hard miter circuit 41 is controlled by the timer sync program (outputs an output for a fixed period of time at fixed time intervals) 40 of the microcomputer 6 to the operational element (NOR).
O+, below the threshold voltage of 02, that is, Low
level. At that time, the transistor 48 of the recent circuit 47 is in the operating state yF;, and the voltage at the b terminal of the operational element (NOR) 02 is L through the diode D2.
It is o w level. However, when the timer sync program 40 no longer operates properly due to a runaway of the microcomputer 6, the voltage of the capacitor C1 of the hard drive circuit 41 increases with the time constant of R2 and C0, and the voltage is calculated via the resistor R3. When the C terminal voltage of the element (NOR) O+ exceeds the threshold voltage of the operational element (NOR) o, +02, the C terminal voltage becomes Low level and the operational element (NO
R)020') The C terminal voltage becomes High level. Furthermore, the b terminal voltage of the arithmetic element (NOR) 01 is R5・C
If it reaches H4gh level with a time constant of 2, the C terminal voltage of the operational element (NOR) O+ becomes LOWlz level regardless of the voltage level of the a terminal, and both the a terminal and b terminal voltage of the operational element (NOR) 02 become At Low level, the C terminal voltage becomes High level and is latched. Also, R5・C
A time constant of 2 prevents this latch due to noise. When launched in this way, the base voltage of the transistor 42 of the relay drive circuit 43 is kept at a low level via the transistor D1, and the safety of the system is maintained in order to keep the switching part (43) in an inoperable state. It is maintained.

Furthermore, the C terminal voltage of the arithmetic element (NOR) 02 is Hi
Since the controller 3 is latched to the gh level, the LED remains lit, and it is easy to determine whether there is a defect inside the controller 3 or not.

FIG. 6 is a diagram showing a specific example of a case 50 that houses the controller 3, in which a circuit board 51 on which a microcomputer 6 and the like constituting the controller 3 are mounted is housed in a case body 52, and a case cover 53 covers the circuit board 51. It will be sealed. This case cover 53 is provided with a through hole 54 made of a transparent lens or the like, and the LED element 45 as the external display mechanism 44 provided on the circuit board 51 is attached in a corresponding position.

Therefore, in the unlikely event that an abnormality occurs in the controller 3, the LED element 45 remains lit as described above. Therefore, whether or not the system abnormality is caused by something inside the controller 3 can be determined by looking through the through hole 54 provided in the case 50 and checking whether the LED element 45 is lit. Further, the external display device 46 may be provided on the driver's seat side, if necessary.

(Effects of the Invention) As explained above, according to the present invention, there is provided a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, a command switch that generates a cruise command signal, and a memory that stores the vehicle speed when the command switch is operated. an actuator that drives a throttle valve; a controller that sends a command to the actuator in response to a difference between the actual vehicle speed and the stored vehicle speed; and a switching section that turns on and off power supply to the actuator; In the automatic vehicle speed control device equipped with the above, a latch circuit is provided that holds the switching section in an inoperable state and operates an external display mechanism when the controller malfunctions,
In the unlikely event that there is a malfunction in the system of the automatic vehicle speed control device, it is possible to easily determine from the outside of the controller whether or not the system malfunction is a malfunction inside the controller I/roller. It has the very excellent effect of being able to significantly improve reliability and maintainability.

[Brief explanation of the drawing]

FIG. 1 is a block explanatory diagram showing a configuration example of a conventional automatic vehicle speed control device, FIG. 2 is a cross-sectional explanatory diagram showing an example of the structure of the actuator in FIG. 1, and FIG. 4 is a block diagram illustrating a configuration example of an automatic vehicle speed control device according to an embodiment of the present invention; FIG. 5 is a diagram illustrating specific examples of the hard timer circuit and latch circuit shown in FIG. 4. FIG. 6 is an explanatory diagram showing a configuration example, and FIG. 6 is an exploded perspective explanatory diagram of the controller storage case. DESCRIPTION OF SYMBOLS 1... Vehicle speed sensor, 2... Command switch 5... Controller, 6... Microcomputer, 10... Actuator, 11... Vent valve. DESCRIPTION OF SYMBOLS 12...Safety valve, 13.../Hecum valve, 17...Negative pressure chamber, 12...Throttle valve shaft, 21...Switching part for GENTHELBU, 22...
Swing unit for vacuum pulp, 25... Relay, 33... Power supply, 42... Latch circuit. 43... Relay drive circuit (actuator switching section), 44... External display mechanism. Patent applicant Patent attorney representing Jidosha Electric Industry Co., Ltd.
Yutaka Koshio Figure 2 1n Figure 3 Figure 5 Figure 6

Claims (2)

[Claims] (1) A vehicle speed sensor that generates a signal proportional to the actual vehicle speed, a command switch that generates a cruise command signal, a vehicle speed storage unit that stores the vehicle speed when the command switch is operated, an actuator that drives the throttle valve, and the In an automatic vehicle speed control device including a controller that sends a command to the actuator in response to a difference between an actual vehicle speed and a memorized vehicle speed, and a switching unit that turns on and off power supply to the actuator, when the controller malfunctions, An automatic vehicle speed control device comprising a latch circuit that holds the switching section in an inoperable state and operates an external display mechanism. (2) The automatic vehicle speed control device according to claim (1), wherein the external display mechanism includes a light emitting element that is visible from outside the controller storage case.