JPH0333536B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is an improvement of a constant speed cruise control device for a vehicle that controls the throttle valve opening of a vehicle prime mover so that the detected own vehicle speed becomes equal to a set vehicle speed. It is related to.

<Prior art> In a device that compares the vehicle speed with a set vehicle speed and controls the vehicle speed so that the vehicle speed becomes equal to the set vehicle speed, if a failure occurs in any part, the device accelerates regardless of the vehicle speed setting. There is a possibility that control may be exercised by the party who does the work. In such a case, problems such as the speed of the own vehicle exceeding the legal speed and deterioration of fuel efficiency of the vehicle occur.

In order to solve such problems, the special public
The following technology is proposed in Publication No. 47374. This is an automotive speed control system that generates an output signal in an output amplifier circuit in response to a control signal that is the output of a differential amplifier circuit that compares the own vehicle speed and a set vehicle speed, and drives a throttle valve in accordance with this output signal. The control device is characterized in that it is provided with a safety circuit that cancels control when the output signal instructs acceleration even though the control signal instructs deceleration. In conventional technology, if the output terminal of the output amplifier circuit is fixed at a high potential level due to some kind of failure, the throttle valve is driven in the opening direction, but with this technology, the output signal is fixed at a high potential level. By providing a safety circuit that turns off the power supply holding relay when the control signal is at a low potential level, vehicle speed control is canceled in the event of the above abnormality.

<Problem to be solved by the invention> However, even with this technology, if the output terminal of the differential amplifier circuit is shorted to the power supply side and the control signal is fixed at a high potential level, the output amplifier circuit will Since a high-level output signal is output in accordance with the control signal, the throttle valve is driven in the opening direction, and the vehicle speed may increase abnormally. At this time, since both the control signal and the output signal are high level signals, the safety circuit determines that they are in a normal state, so the power supply holding relay does not turn off.

An object of the present application is to solve the above-mentioned problem, which cannot be solved even by the technology proposed in the above-mentioned publication, by monitoring vehicle speed.

<Means for Solving the Problems> In order to solve the above problems, the present application provides a vehicle speed detection means for detecting the own vehicle speed, a set vehicle speed storage means for storing the set vehicle speed, and a third vehicle speed for comparing the own vehicle speed and the set vehicle speed. 1 comparison means; and a throttle valve opening degree control means for controlling the throttle valve opening degree of the vehicle prime mover according to the output of the first comparison means, and controls the own vehicle speed so as to be equal to a set vehicle speed. In a constant speed cruise control device for use, a set vehicle speed adding means adds a predetermined vehicle speed to the set vehicle speed, an output signal of the set vehicle speed adding means and an output signal of the vehicle speed detecting means are compared, and an output signal of the vehicle speed detecting means is determined. A second comparing means generates an output signal when the output signal becomes larger than the output signal of the set vehicle speed adding means, and a canceling means cancels the throttle valve opening control in response to the output signal of the second comparing means. It is characterized by

<Function/Effect> With this configuration, when the own vehicle speed exceeds the set vehicle speed by a predetermined value or more, the throttle valve opening control is canceled by the release means, so that the own vehicle speed exceeds the set vehicle speed and becomes abnormally large. can be prevented.

<Example> An example of the present invention will be described based on the drawings.
The drawing shows a functional block diagram of an example of a constant speed cruise control device for a vehicle 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 placed in a position that is easy for the driver to operate; and is used to command the start of vehicle speed control; 44, 46, and 48 are all for canceling vehicle speed control. A stop lamp switch detects the operation of the brake pedal, and a clutch switch detects the operation of the clutch pedal (or, in a torque converter vehicle, moves the shift lever to the parking position,
Alternatively, there are a neutral start switch (hereinafter referred to as a clutch switch) that detects that the brake is operated to the neutral position, and a parking brake switch that detects that the parking brake is operated. 28 is an actuator for driving a throttle valve of a vehicle prime mover (not shown), and 60 is a control circuit.

The output of the vehicle speed sensor 10 is converted into a voltage proportional to the vehicle speed by an F-V conversion circuit 14 and inputted to a storage circuit 18 via an analog switch 16. The memory circuit 18 stores the vehicle speed voltage immediately before the analog switch 16 is switched from on to off. The comparator 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, and vice versa. As the former is higher than the latter, a pulse signal with a smaller duty ratio is output. The output of the comparison circuit 20 is the AND gate 2
4 and the drive circuit 26 to drive the control valve 28a of the actuator 28.

On the other hand, since the output of the set switch 38 becomes a logic 0 signal when operated, it is inverted by the not gate 40 and output to the analog switch 16 and the self-holding circuit 3.
4 is input. The analog switch 16 is turned on when a logic 1 signal is input from the not gate 40. Furthermore, when a logic 1 signal is input from the not gate 40, the self-holding circuit 34 outputs a logic 1 signal and maintains that state. Knot gates 53 and 52 connected to the outputs of clutch switch 46 and parking brake switch 48 perform the same function as knot gate 40. Stop lamp switch 44 outputs a logic 1 signal when the brake pedal is operated, so no not gate is required. These switches 44, 46,
When at least one of the output signals 48 is operated, the signal is input to the self-holding circuit 34, and the self-holding circuit 34 releases the output signal from the logic 1 state and outputs a logic 0 signal. The output of the self-holding circuit 34 is supplied to one input of the AND gate 24 and drives the release valve 28b of the actuator 28 via the AND gate 51 and the drive circuit 36. The other input of the AND gate 51 is supplied with an inverted output from a comparison circuit 50 provided in parallel with the comparison circuit 20 . This comparison circuit 50
is an addition (not shown) that adds a predetermined voltage to the vehicle speed voltage output from the memory circuit 18 to generate a voltage corresponding to a vehicle speed higher than the vehicle speed stored in the memory circuit 18 by a predetermined value (for example, 15 km/h). The output voltage of this adder circuit and F-V
It compares the vehicle speed voltage output from the conversion circuit 14 and outputs a logic 1 signal when the vehicle speed voltage output from the F-V conversion circuit 14 becomes higher.

The actuator 28 is normally connected to the negative pressure port 28d.
is closed and the atmosphere release port 28c is opened, and when a signal is received from the drive circuit 26, the atmosphere release port 28c is closed in response to the signal and the negative pressure port 28d is opened.
A control valve 28a that generates negative pressure in the diaphragm chamber 28e when opened, and a release valve 28b that normally opens the atmosphere release port 28f and closes the atmosphere release port 28f when receiving a signal from the drive circuit 36. , the diaphragm 28g defining the diaphragm chamber 28e is connected to the throttle valve of the vehicle prime mover, and the inside of the diaphragm chamber 28e becomes negative pressure, causing the diaphragm 2
When the diaphragm 8g is deformed, the link 28h is pulled in the direction of the arrow A in the figure to increase the opening degree of the throttle valve, and the spring 28i constantly biases the diaphragm 28g in the direction opposite to the arrow A. The drive circuit 26 operates so that the period during which the negative pressure port 28d is open increases as the duty ratio of the input signal increases.

Next, the operation of this 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-V
The vehicle speed voltage from the conversion circuit 14 is supplied to the storage circuit 18 . When the operation of the set switch 38 is completed, the analog switch 16 is turned off, and the memory circuit 18 stores the immediately previous vehicle speed voltage as the set vehicle speed. At this time, the self-holding circuit 34 outputs a logic 1 signal, and supplies the signal to one input of each of the AND gates 24 and 51. Since the comparison circuit 50 outputs a logic 0 signal, the AND gate 51 outputs a logic 1 signal, and the drive circuit 36 outputs a logic 1 signal.
8b and close the atmospheric release port 28f. The comparison circuit 20 compares the vehicle speed voltage from the F-V conversion circuit 14 and the vehicle speed voltage from the storage circuit 18, and generates a pulse signal with a larger duty ratio as the vehicle speed voltage from the F-V conversion circuit 14 is smaller. The pulse signal is supplied to the drive circuit 26 via the AND gate 24, and the control valve 28a is driven so that the negative pressure port 28d and the atmosphere release port 28c are alternately opened and closed in response to this pulse signal. The larger the duty ratio, the longer the period during which the negative pressure port 28d is open, so a negative pressure corresponding to the memorized set vehicle speed is generated in the diaphragm chamber 28e of the actuator 28, causing the diaphragm 28g to deform and link 2
Pull 8h in the direction of arrow A. When the vehicle speed becomes lower than the set vehicle speed, the negative pressure in the diaphragm chamber 28e increases, and the link 28h is pulled more strongly to increase the vehicle speed. When the vehicle speed becomes higher than the set vehicle speed, the negative pressure in the diaphragm chamber 28e becomes smaller, and the force that pulls the link 28h becomes weaker, so the vehicle speed decreases. By continuing the above control, control is performed to bring the vehicle speed closer to the set vehicle speed.

If you depress the brake pedal or clutch pedal or operate the parking brake while performing this vehicle speed control, switches 44, 46,
48 is turned on, the output of self-holding circuit 34 is switched from a logic 1 to a logic 0 signal. Therefore, transmission of the pulse signal to the drive circuit 26 via the AND gate 24 is stopped, and transmission of the pulse signal to the drive circuit 3 via the AND gate 51 is stopped.
6 is also stopped. As a result, the operation of the control valve 28a and the release valve 28b is stopped, and the diaphragm chamber 2 is opened from the atmosphere release ports 28c and 28f.
Atmospheric air is introduced into the vehicle 8e, the actuator 28 is deactivated, and the constant speed driving control is deactivated.

When controlling the vehicle speed, for example, if the control valve 28a or the drive circuit 26 breaks down and the atmospheric release port 28c closes and the negative pressure port 28d remains open, the diaphragm chamber The negative pressure inside 28e becomes larger and larger, and the link 28h comes to be strongly pulled in the direction of arrow A, regardless of the set vehicle speed, and the vehicle speed begins to increase beyond the set vehicle speed. However, in the present invention, the vehicle speed is lower than the set vehicle speed by a predetermined value, for example, 15
When the value exceeds Km/h, the comparator circuit 50 outputs a logic 1 signal, so the AND gate 51 outputs a logic 0 signal.
Since the drive circuit 36 stops driving the release valve 28b, the atmosphere release port 28f is opened. Then, atmospheric pressure is supplied into the diaphragm chamber 28e from the atmosphere release port 28f, the negative pressure inside the diaphragm chamber 28e weakens, and the link 28h is returned in the direction opposite to the arrow A. This causes the throttle to be operated in the closing direction, thereby reducing the vehicle speed. The vehicle speed is set to the predetermined value (15Km/
h), the comparator circuit 50
outputs a logic 0 signal, so AND gate 5
1 again transmits the signal from the self-holding circuit 34 to the drive circuit 36 to operate the release valve 28b and close the atmosphere release port 28f. Then, the negative pressure in the diaphragm chamber 28e is strengthened by the negative pressure supplied from the opened negative pressure port 28d, and the vehicle speed increases again.

By repeating such operations, the vehicle speed is controlled to a value higher than the set vehicle speed by a predetermined value. By appropriately selecting this predetermined value,
Even if a failure that increases the vehicle speed occurs, it is possible to reliably prevent the vehicle speed from increasing abnormally, and the vehicle can travel at a substantially constant speed.

Note that the present invention is not limited to the embodiments described above, and includes various embodiments without departing from the gist of the invention.

[Brief explanation of the drawing]

The drawing is a block diagram showing an electric circuit according to an embodiment of the present invention. 10... Vehicle speed sensor, 14... F-V conversion circuit, 18... Memory circuit, 20... Comparison circuit, 26
... Drive circuit, 28 ... Actuator, 28a...
... Control valve, 28b ... Release valve, 34 ... Self-holding circuit, 36 ... Drive circuit, 38 ... Set switch, 50 ... Comparison circuit, 60 ... Control circuit.

Claims (1)

[Claims] 1 A vehicle speed detection means for detecting the own vehicle speed, a set vehicle speed storage means for storing the set vehicle speed, a first comparison means for comparing the own vehicle speed and the set vehicle speed, and a throttle control of the vehicle prime mover according to the output of the first comparison means. A constant speed traveling device for a vehicle, comprising a throttle valve opening degree control means for controlling a throttle valve opening degree, and controlling the own vehicle speed so as to be equal to a set vehicle speed, a set vehicle speed adding means for adding a predetermined vehicle speed to the set vehicle speed. and second comparing means for comparing the output signal of the set vehicle speed adding means with the output signal of the vehicle speed detecting means and generating an output signal when the output signal of the vehicle speed detecting means becomes larger than the output signal of the set vehicle speed adding means. and a release means for releasing the throttle valve opening control in response to the output signal of the second comparison means.