JPH0214212B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a constant speed traveling device for a vehicle that stores the actual vehicle speed when a set switch is operated as a set vehicle speed, and controls the vehicle speed in a direction that makes the deviation between the actual vehicle speed and the set vehicle speed zero. , relates to a safety circuit when the output stage fails and enters a short state.

Conventionally, constant speed running devices usually have a trouble monitor function to detect failures in output stage load circuits such as coils, and to ensure safe driving of the vehicle by preventing the constant speed running device from operating when a failure is detected. There is. However, the output stage transistor may be destroyed due to thermal causes or temporary large current flow due to external noise, resulting in an uncontrollable shot state.

In such a case, there is a risk that the vehicle running at a constant speed will speed up and eventually go out of control, and if the number of check routines is further increased as a preventive measure, the software will become complicated and the reliability of computer control will decrease. Not only is there a risk that the reliability of the check performed by this check routine may be lowered, but it also has the disadvantage that it is not necessarily a definitive solution to the problem.

Under these circumstances, it has been desired to provide a constant speed traveling device having a simple structure and having an even better fail-safe function to solve the above problem.

The purpose of the present invention is to provide a cancel circuit in the control circuit of a constant speed traveling device, which is interposed between a power source and an output stage circuit, and which is provided when the operation of a throttle valve is released by atmospheric pressure control by a release valve. To,
An object of the present invention is to provide a constant speed traveling device that exhibits an excellent fail-safe function by providing an output stage control circuit that cuts off power supply from a power source to an output stage circuit.

Below, the configuration of an embodiment of the present invention will be explained with reference to the drawings.

The vacuum actuator 4 that opens the throttle valve 2 of the carburetor 1 by negative pressure against the elastic force of the spring 3 during auto-drive driving using a constant speed running device includes a vacuum chamber 5 of the actuator 4. A control valve for controlling negative pressure, that is, an excitation coil for control valve control (hereinafter referred to as control coil) 6
The negative pressure in the vacuum chamber 5 is targeted by pulse control with the duty (ratio) as shown in FIG. 2D of introducing negative pressure by turning on (the state shown in FIG. 1) and introducing atmospheric pressure by turning it off. A control valve 7 is installed to create a negative pressure corresponding to the vehicle speed and throttle valve 2 opening degree. Furthermore, when canceling the auto drive, atmospheric pressure is introduced all at once into the vacuum chamber 5 of the actuator 4.
A release valve 8 is installed to quickly release the control of the throttle valve 2 by the vacuum chamber 5 when the control excitation coil (hereinafter referred to as release coil) 9 is turned off.
Atmospheric pressure is introduced into the device, and when it is turned on, atmospheric pressure introduction is stopped.

Furthermore, the control coil 6 includes an output stage circuit (hereinafter simply referred to as a control output stage circuit) 12 for driving a control valve that amplifies the control signal output from the auto drive control circuit 10 by setting the set switch 11. The output of the output stage circuit 12 is connected to an output stage circuit (hereinafter simply referred to as the release output stage circuit) 15 for driving a release valve that drives the release coil 9.
The output stage control circuit 14 is turned on and off by the output of the output stage control circuit 14. The release output stage circuit 15 is connected to the auto drive control circuit 10.
The output of the cancel switch 13 is turned off when the cancel switch 13 is turned on.

Note that FIG. 3 shows each output stage circuit 1 in FIG.
2, 15 and the output stage control circuit 14 are transistors.
This circuit is formed by Tr1 to Tr3 and resistors R1 to R5, and the circuits shown in FIGS. 1 and 3 are configured according to the flowchart shown in FIG. It is controlled as shown in the chart. Each step constituting the flowchart will be explained below.

101 represents a step for determining whether or not the cancel switch 13 is turned on, as shown in FIG. 2A.

102 represents a step for determining whether or not the set switch 11 is turned on, as shown in FIG. 2B, when the cancel switch 13 is not turned on.

103 determines whether or not the vehicle is running in autodrive when the set switch 11 is not turned on, that is, whether or not a set flag F indicating that autodrive mode is set is set to "1". Represents a step.

104 represents a step of turning on the release output stage circuit 15 when the set flag F is "1".

105 represents a routine for turning on autodrive control.

106 represents a step for resetting the set flag F to "0" when the cancel switch 13 is on.

107 represents a step for turning off the release output stage circuit 15.

108 represents an autodrive control off routine.

109 represents a step for setting the set flag to "1" when the set switch 11 is on.

The flow of the process will be explained below according to the flowchart shown in FIG.

First, when the key switch is input, predetermined initial settings are made in a step (not shown), and then
At step 101, it is determined whether or not the cancel switch 13 is turned on. If the cancel switch 13 is turned off, the determination result is "NO" and the process moves to step 102, where it is determined whether or not the set switch has been turned on. It will be judged.

If the determination result in step 102 is ``YES'', the process proceeds to step 109, where the set flag F is set to ``1'' and the process returns to step 101, where it is again determined whether or not the cancel switch 13 has been turned on, and the result is If “NO”, step 1
Move to 02. In step 102, if the set switch 11 has changed from on to off, it is determined that the set operation has been completed, and the determination result is "NO", and the next step 103 is executed.
In step 103, it is determined whether or not the set flag F has been set. Since it has already been set, the determination result is "YES", and the process moves to the next step 104, where the release output stage circuit 15 is set. After the process of outputting a high level signal as shown in FIG. 2C is executed, the "auto drive control on" routine 105 is executed, and then the process returns to step 101 again. Until the cancel switch 13 is turned on, the closed loop process formed by steps 101, 102, 103, 104, and routine 105 is performed, and the automatic drive running state is maintained.

If the cancel switch is turned on during the execution of the above closed loop, the judgment result becomes "YES" in step 101, and as a result, step 1
06, the set flag F is reset,
Subsequently, in step 107, the release output stage circuit 1
The release valve control signal outputted to 5 is set to a low level, and the release valve 8 is opened to the atmosphere.Furthermore, autodrive driving is canceled in an "autodrive control off" routine 108.

In the auto drive control circuit 10 which is controlled as explained above, the cancel switch 1
3 is detected, the release valve control signal from the autodrive control circuit 10 is turned off, and the release output stage circuit 15, for example, the transistor Tr3 is turned off to forcibly apply atmospheric pressure to the vacuum chamber 5 of the actuator 4. As a result, the control output stage circuit 12,
For example, when the power supply to the transistor Tr1 is cut off and the control coil 6 is in an auto drive cancel state, the control output stage circuit 1
2. Even if, for example, the transistor Tr1 is in an uncontrollable short-circuit state, the vehicle can be easily and reliably prevented from entering a dangerous high-speed driving state with 100% duty by simplifying the structure.

In the other embodiment shown in FIG. 5, the control function of the transistor Tr2 in FIG. 3 corresponding to the output stage control circuit 14 in FIG. Transistor Tr3 in the diagram
The configuration, operation, and effects are almost the same as those of the previous embodiment except that it is also used for the same purpose.

As described in detail above, the safety circuit of the output stage in the constant speed running system for a vehicle of the present invention is the output stage of the constant speed running system for a vehicle that operates the throttle valve by controlling the negative pressure of the actuator using the control valve and the release valve. In the stage, power is supplied to an output stage circuit that transmits a control signal to a control excitation coil that controls a control valve via an output stage control circuit. This output stage control circuit is configured to cut off power supply from the power source to the output stage circuit when atmospheric pressure control is performed by the release valve. Therefore, when atmospheric pressure control of the release valve is performed by operating a cancel switch, etc., the power to the output stage circuit that transmits the control signal to the control excitation coil is also cut off, and the control valve operation is canceled. Therefore, at the same time as performing the fail-safe function of releasing the throttle valve operation by controlling the atmospheric pressure of the release valve,
A second failsafe function of deactivating the control valve is also performed.

Therefore, according to the present invention, even if, for example, the output stage circuit fails and a control signal is constantly transmitted to the control excitation coil, it is possible to reliably release the operation of the control valve. Therefore, together with releasing the operation of the throttle valve by controlling the atmospheric pressure of the release valve, high safety can be achieved with a simple configuration. Further, if the output stage circuit for driving the excitation coil for controlling the release valve is also used as the output stage control circuit, there is an effect that the number of circuit component parts can be reduced and costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is its operation diagram, Fig. 3 is a specific electric circuit diagram corresponding to the schematic diagram of Fig. 1, and Fig. 4 is its flowchart. 5 are specific electrical circuit diagrams of other embodiments of the present invention. 2... Throttle valve, 4... Actuator, 6... Control coil, 7... Control valve, 8... Release valve, 9... Release coil, 10... Auto drive control circuit,
12... Control output stage circuit, 14... Output stage control circuit, 15... Release output stage circuit.

Claims (1)

[Claims] 1. The opening degree of the throttle valve is controlled by negative pressure and atmospheric pressure control by a control valve provided on a vacuum actuator, and
A constant speed traveling device for a vehicle that releases the operation of a throttle valve by atmospheric pressure control using a release valve provided on the vacuum actuator, regardless of whether the throttle valve is operated by the vacuum actuator, comprising: a power source; a control excitation coil that controls the drive of the control valve; an output stage circuit that transmits a control signal during constant speed running to the control excitation coil; and a release valve that is interposed between the power source and the output stage circuit. and an output stage control circuit that cuts off power supply from the power source to the output stage circuit when the operation of the throttle valve is released by atmospheric pressure control. Safety circuit of output stage in traveling equipment.