JPH0147329B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a vehicle speed control method for controlling the throttle valve opening of a vehicle prime mover so that the vehicle speed becomes a preset vehicle speed.

Conventional vehicle speed control methods compare the detected vehicle speed and the set vehicle speed, and if the former is smaller than the latter, the speed is increased, and if the latter is larger, the speed is decelerated. If a failure occurs in the detection circuit system and the detected vehicle speed value becomes lower than the actual vehicle speed, or if the detected vehicle speed value remains at zero, the vehicle speed will be controlled to increase unilaterally. there is a possibility. Therefore, the present inventors focused on the fact that the detected vehicle speed becomes abnormally low compared to the set vehicle speed in the event of a failure as described above, and when the detected vehicle speed becomes less than a predetermined value relative to the set vehicle speed, the throttle We considered canceling the tutle valve opening control to prevent the vehicle speed from being increased unilaterally.

However, if the control is canceled when the detected vehicle speed becomes lower than the set vehicle speed, the resume function that allows the control to be restarted after the control has been canceled, or the current vehicle speed It is conceivable that the preset function that allows the set vehicle speed to be set may become inoperable at speeds lower than the set vehicle speed.

In view of the above points, an object of the present invention is to prevent unilateral speed increase control when the detected vehicle speed becomes abnormally low, and to also enable the resume function or preset function.

In order to achieve this objective, in the present invention,
The detected vehicle speed and the set vehicle speed are compared, and when the former is lower than the latter by a predetermined value or more, the throttle valve opening control is canceled, and after starting the throttle valve opening control, the set vehicle speed is changed. The cancellation operation is prohibited unless the detected vehicle speed becomes higher than a specific vehicle speed between the set vehicle speed and the vehicle speed lower by the predetermined value.

Therefore, according to the present invention, the resume function or preset function can be made effective while preventing the vehicle speed from increasing unilaterally in response to a failure in which the detected vehicle speed becomes abnormally low.

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

The drawing mainly shows a block diagram of an electric circuit in a vehicle speed control device embodying the present invention.

10 is a vehicle speed sensor that is turned on and off at a frequency proportional to the vehicle speed; 38 is a set switch that is placed in a position that is easy for the driver to operate and instructs the start of vehicle speed control; 30 is located close to the set switch 38 and is used to release the vehicle speed control. A resume switch 80 instructs to start operating a resume function when operated during vehicle speed control, and instructs to operate a speed increasing function to increase the vehicle speed during that time when operated during vehicle speed control. A preset switch 82, which is placed close to the set switch 38 and the resume switch 30 and commands to control the vehicle speed at a speed set by a vehicle speed setting device 82, which will be described later, is placed at a position that is easy for the driver to operate. a vehicle speed setting device for arbitrarily selecting and setting a preset vehicle speed;
6 and 48 are switches that detect an operation to cancel vehicle speed control and issue a command to cancel it, such as a stop lamp switch that detects the operation of the brake pedal, and a clutch switch (or a clutch switch in a torque converter vehicle) that detects the operation of the clutch pedal. a neutral start switch that detects that the shift lever is operated to the parking position or neutral position; a parking brake switch that detects the operation of the parking brake; and 28, a drive that changes the opening degree of the throttle valve of the vehicle prime mover (not shown). 90 is a control circuit.

The output of the vehicle speed sensor 10 is output from an analog switch 86.
The voltage is converted into a voltage proportional to the vehicle speed by the F-V conversion circuit 14 via the analog switch 16.
It is input to the memory circuit 18. Therefore, memory circuit 1
8 stores the vehicle speed voltage immediately before the analog switch 16 is switched from on to off. Comparison circuit 20
compares the vehicle speed voltage output from the F-V conversion circuit 14 and the vehicle speed voltage output from the memory circuit 18, and outputs a pulse signal with a larger duty ratio as the former is lower than the latter; The higher the duty ratio is, the smaller the pulse signal is output. The output of the comparison circuit 20 is supplied to the drive circuit 26 via an OR gate 42 and an AND gate 24. On the other hand, the output of the set switch 38 becomes a logic 0 signal when operated, so the not gate 40
It is inverted at , and is input to the analog switch 16 and the set input of the self-holding circuit 66 via the OR gate 41, and is also supplied to the set input of the self-holding circuit 34 via the OR gate 74. The analog switch 16 is turned on when a logic 1 signal is input from the OR gate 41. Furthermore, when the self-holding circuits 34 and 66 receive a logic 1 signal at their set inputs, they are set and output a logic 1 signal.
outputs a signal and maintains that state. The output of the resume switch 30 is also supplied to one input of an AND gate 70 via a not gate 32, and also to one input of an OR gate 74. The output of AND gate 70 is OR gate 4
1, one input of OR gate 42, and one input of AND gate 68, respectively. When input to one input of AND gate 68, the logic is inverted. Further, the output of the preset switch 80 is connected to each input of the OR gates 41, 74, 76, the analog switch 86, and the F-V conversion circuit 8 via the not gate 78.
4. The output of OR gate 76 is applied to the reset input of self-holding circuit 64 to reset self-holding circuit 64, releasing it from its holding state and providing a logic 0 signal at its output. When the analog switch 86 receives a logic 1 signal from the not gate 78, it cuts off the circuit from the vehicle speed sensor 10 and closes the circuit from the V-F conversion circuit 84. When the V-F conversion circuit 84 receives a logic 1 signal from the not gate 78, it converts the voltage corresponding to the set vehicle speed generated by the vehicle speed setter 82 into a signal with a frequency proportional to the voltage, and converts the voltage generated by the vehicle speed setter 82 into a signal with a frequency proportional to the set vehicle speed. and supplies it to the F-V conversion circuit 14. Stop lamp switch 44, clutch switch 4
6 and parking brake switch 48 are input to the reset input of self-holding circuit 34 via OR gates 62 and 60 to reset self-holding circuit 34. The output of the self-holding circuit 34 is supplied to the drive circuit 36 and the other input of the AND gate 24, and is also input to the reset input of the self-holding circuit 66 via the NOT gate 72. Further, the output of the self-holding circuit 66 is input to the other input of the AND gate 70. However, since the outputs of the clutch switch 46 and the parking brake switch 48 are logic 0 signals when they are operated, their logics are inverted when these signals are input to the OR gate 62. Stop lamp switch 4
Since the output of 4 is a logic 1 signal during its operation,
No need to flip. Further, the comparison circuit 20 is provided with comparison circuits 50 and 56 in parallel, an amplifier circuit 52 is connected between one comparison input of the comparison circuit 50 and the output of the storage circuit 18, and one comparison input of the comparison circuit 50 is connected to an amplifier circuit 52. A storage circuit 18 stores the voltage supplied to the input.
3/4 times the output voltage. An amplifier circuit 54 is also connected between one comparison input of the comparison circuit 56 and the output of the storage circuit 18, and the voltage supplied to one comparison input of the comparison circuit 56 is set to 7/7 of the output voltage of the storage circuit 18. Multiply by 8. When the voltage from the F-V conversion circuit 14 becomes smaller than the voltage from the amplifier circuit 52, the comparison circuit 50 outputs a logic 1 signal, which is supplied to one input of the AND gate 58. The output of AND gate 58 is supplied to the reset input of self-holding circuit 34 via OR gate 60. Furthermore, when the voltage from the F-V conversion circuit 14 becomes larger than the voltage from the amplifier circuit 54, the comparator circuit 56 outputs a logic 1 signal, supplies it to the set input of the self-holding circuit 64, and sets the self-holding circuit 64. and its output is set to logic 1.

The actuator 28 closes the atmosphere release port 28c and opens the negative pressure port 28d when it receives a signal from the drive circuit 26, and has a control valve 28a that normally closes the negative pressure port 28d and opens the atmosphere release port 28c, and a drive circuit 28a. A release valve 28b that closes the atmospheric release port 28f when receiving a signal from the circuit 36 and normally leaves it open; a diaphragm 28g that defines a diaphragm chamber 28e;
g and the throttle valve of the vehicle's prime mover,
When the diaphragm 28g is deformed by applying negative pressure to the diaphragm 28g, it moves in the direction of arrow A to increase the opening degree of the throttle valve and the output of the prime mover. It has a spring 28i that is always biased in the opposite direction to A.

Next, the operation of the above embodiment will be explained.

When the set switch 38 is operated while the vehicle is running at a certain speed, the analog switch 16 is turned on and the F
-The vehicle speed voltage from the V conversion circuit 14 is stored in the memory circuit 18.
supplied to When the operation of the set switch 38 is completed, the analog switch 16 is turned off, and the memory circuit 18 stores the vehicle speed voltage immediately before the analog switch 16 is turned off as the set vehicle speed. Further, when the set switch 38 is operated,
The self-holding circuit 34 is set and outputs a logic 1 signal, thereby opening the AND gate 24 and supplying a signal to the drive circuit 36 to close the release valve 28b.
is operated so that the atmosphere release port 28f is closed. On the other hand, in the comparison circuit 20, the F-V conversion circuit 14
The vehicle speed voltage from the memory circuit 18 is compared with the vehicle speed voltage from the memory circuit 18, and a pulse signal with a duty ratio corresponding to the difference is supplied to the drive circuit 26 via the OR gate 42 and the AND gate 24, and the pulse signal is connected between the negative pressure port 28d and the atmosphere. The control valve 28a is operated so that the open port 28c and the open port 28c are alternately opened and closed. Therefore, the diaphragm chamber 28e of the actuator 28 becomes a negative pressure corresponding to the memorized set vehicle speed, and the diaphragm 28e
8g is transformed and the link 28h is moved in the direction of arrow A. In other words, when the vehicle speed becomes lower than the set vehicle speed, the negative pressure in the diaphragm chamber 28e becomes stronger, and the link 28h is moved largely in the direction of arrow A to increase the vehicle speed, and when the vehicle speed becomes higher than the set vehicle speed, the negative pressure in the diaphragm chamber 28e becomes weaker. , the link 28h is moved in the direction opposite to the direction of arrow A to reduce the vehicle speed. By repeating this control, the vehicle speed is controlled to approach the set vehicle speed.

While controlling the vehicle speed in this way, if you depress the brake pedal or clutch pedal or operate the parking brake, switches 44 and 4
Since at least one of 6 and 48 turns on, the self-holding circuit 34 is reset and its output is switched from logic 1 to 0, closing the AND gate 24 and stopping the operation of the control valve 28a, and releasing the control valve 28a. The operation of the valve 28b is also stopped, and the diaphragm chamber 28e is opened to the atmosphere opening ports 28c and 28.
Atmospheric pressure is rapidly supplied via f, link 28
h is quickly returned to its original position. Therefore, vehicle speed control is canceled at this time.

While the vehicle speed is being controlled, a failure may occur in the mechanism that turns the vehicle speed sensor 10 on and off, or a failure may occur in the F-V conversion circuit 14, causing the vehicle speed voltage to become lower than the actual vehicle speed. , becomes zero, F compared to the vehicle speed voltage in the memory circuit 18.
Since the voltage of the -V conversion circuit 14 becomes low, the comparator circuit 20 outputs a signal that abnormally increases the vehicle speed. However, in the present invention, this problem is solved as follows. That is, in the comparison circuit 50, the voltage of the F-V conversion circuit 14 and the voltage of the amplifier circuit 52 are compared, and when the former is lower than the latter, that is, it is detected by the vehicle speed sensor 10, and the voltage of the F-V conversion circuit 14 is detected. When the vehicle speed value converted into a DC voltage becomes 3/4 or less of the set vehicle speed stored in the storage circuit 18, the comparison circuit 50 outputs a signal of logic 1. On the other hand, when the vehicle speed control is normally performed, the detected vehicle speed is approximately equal to the set vehicle speed, so the memory voltage of the memory circuit 18 multiplied by 7/8 via the amplifier circuit 54 is F-
The vehicle speed voltage from the V conversion circuit 14 is sufficiently higher,
Comparison circuit 56 outputs a logic 1 signal to set self-holding circuit 64. Therefore, the self-holding circuit 64 outputs a logic 1 signal and opens the AND gate 58 until the reset signal from the OR gate 76 is input. Therefore, the logic 1 signal output from the comparator circuit 50 resets the self-holding circuit 34 via the AND gate 58 and the OR gate 60, thereby canceling the vehicle speed control.

When the resume switch 30 is operated after the vehicle speed control is released, the logic 1 is output from the not gate 32.
A signal is output, and this signal is sent to the OR gate 74.
The self-holding circuit 34 is set again via the self-holding circuit 34, and vehicle speed control is restarted. However, if the vehicle speed at this time is considerably lower than the set vehicle speed, the self-holding circuit 34 will be reset by the logic 1 signal from the comparison circuit 50. However, when the resume switch 30 is operated, a logic 1 signal is supplied to the reset input of the self-holding circuit 64 via the OR gate 74, the AND gate 68, and the OR gate 76, and the self-holding circuit 64 is reset. 58 is closed, the signal of the comparator circuit 50 cannot pass through the AND gate 58, and the self-holding circuit 34
is never reset. When the vehicle speed returns to near the set vehicle speed by restarting the vehicle speed control, a logic 1 signal is output from the comparator circuit 56, so the self-holding circuit 64 is set and the AND gate 58 is output.
is opened, and the signal from the comparator circuit 50 that is output thereafter is allowed to pass through. In other words, if the actual vehicle speed is low immediately after resuming vehicle speed control, vehicle speed control will not be released.
If the detected vehicle speed suddenly becomes low due to a failure in the vehicle speed detection circuit system during vehicle speed control, the self-holding circuit 34 is reset by a signal from the comparator circuit 50 to cancel the vehicle speed control.

When the vehicle speed to be controlled is selected and set using the vehicle speed setter 82 and the preset switch 80 is operated, a logic 1 signal is output from the not gate 78, operating the analog switch 86 and switching the V-F conversion circuit. 84 to set the vehicle speed setting device 8.
A signal with a frequency proportional to the voltage corresponding to the vehicle speed set by 2 is supplied to the F-V conversion circuit 14. At this time, since the analog switch 16 is on, the set vehicle speed converted into a voltage signal by the F-V conversion circuit 14 is stored in the storage circuit 18. Furthermore, since the self-holding circuit 34 is also set via the OR gate 74, when the analog switch 86 is switched to the vehicle speed sensor 10 side after the operation of the preset switch 80 is completed, the vehicle speed is set to the vehicle speed set by the vehicle speed setting device 82. In the past, vehicle speed control was performed. At this time, as in the case of resume, when the preset switch 80 is operated, the self-holding circuit 64 is reset via the OR circuit 76, and after the vehicle speed has been increased to near the set vehicle speed, the output of the comparison circuit 56 is Therefore, since the self-holding circuit 64 is set,
The vehicle speed control is not canceled by the output of the comparator circuit 50 immediately after the start of vehicle speed control by the preset function while the actual vehicle speed is still low, and when the vehicle speed control is being performed at a vehicle speed close to the set vehicle speed. Vehicle speed control is canceled only when the detected vehicle speed suddenly decreases due to a failure.

Next, when the resume switch 30 is operated while controlling the vehicle speed, a signal from the not gate 32 is supplied to the drive circuit 26 via the AND gate 70, the OR gate 42, and the AND gate 24, so that the control valve 28a operates continuously to close the atmospheric release port 28c and maintain the negative pressure port 28d open. Therefore, the vehicle speed is continuously increased while the resume switch 30 is operated. When the reduction switch 30 is operated, the analog switch 16, which had been turned on until then, is turned off, so the set vehicle speed is set to the vehicle speed increased by the operation of the reduction switch 30, and vehicle speed control continues at that speed from then on. do.

Note that the present invention is not limited to the embodiments described above, but includes various embodiments such as those listed below.

(1) An electric motor may be used as the actuator 28.

(2) The amplification circuit 52 and the amplification factor may be made variable, or a subtraction circuit may be used to subtract a predetermined value or a specific value from the voltage of the storage circuit 18.

(3) The control circuit 90 may achieve its functions by executing a program on a microcomputer.

[Brief explanation of drawings]

The drawing is a block diagram showing an electric circuit according to an embodiment of the present invention. 10... Vehicle speed sensor, 18... Memory circuit, 2
0, 50, 56... Comparison circuit, 28... Actuator, 28a... Control valve, 28b... Release valve,
30...Regium switch, 34, 64, 66
... Self-holding circuit, 38 ... Set switch, 8
0... Preset switch, 82... Vehicle speed setting device, 90... Control circuit.

Claims (1)

[Claims] 1. A function that controls the throttle valve opening of the vehicle prime mover so that the vehicle speed reaches a preset vehicle speed, and that enables the control to be resumed after this control is once released.
Alternatively, in a vehicle speed control method that includes a function that allows a set vehicle speed to be set regardless of the current vehicle speed,
The detected vehicle speed and the set vehicle speed are compared, and when the former is lower than the latter by a predetermined value or more, the throttle valve opening control is canceled, and this canceling operation is performed by the throttle valve opening control. After the start of
A vehicle speed control method characterized in that the vehicle speed is prohibited unless the detected vehicle speed becomes higher than a specific vehicle speed between a set vehicle speed and a vehicle speed lower than the set vehicle speed by the predetermined value.