JPS58113551A - Car-speed controller - Google Patents

Abstract

PURPOSE:To maintain the stable traveling state of a car by installing a negative- pressure releasing valve which controls the opening degree of a throttle-valve and urging the negative-pressure releasing valve in the direction of closing the throttle valve, when the higher speed exceeding an objective car-speed is attained. CONSTITUTION:A F-V conversion circuit 20 converts a car-speed signal into a voltage. A memory circuit 50 stores the voltage corresponding to a car-speed voltage signal Vv through the operation of a set switch SW1. The output terminal of a comparator OM1 is connected to a transistor Qp for driving the solenoid SL1 of a negative-pressure control valve, and the output terminal of a comparator CM2 is connected to a transistor Q; for driving solenoid SL2 of the negative-pressure releasing valve through a diode Dg. When the autual car-speed exceeds the objective car-speed, the solenoid of the negative pressure releasing and controlling valve is electically excited or unexcited in the direction of closing the throttle vavle. Thus, the stable traveling state of the car can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides speed setting, storage, and
This invention relates to a speed control device related to release.

Typically, this type of device detects the current vehicle speed as a number of pulses and obtains an analog voltage proportional to the number of pulses as a vehicle speed signal. When the driver reaches a desired vehicle speed, he operates a constant speed travel set switch to set (store) the vehicle speed signal at that time in the memory circuit. The speed control device uses the set vehicle speed signal as a reference voltage for one of the comparator circuits, and adjusts the opening degree of the throttle valve in a direction such that the difference becomes zero based on the difference between the set vehicle speed signal and the current vehicle speed.

This type of constant speed traveling device for a vehicle is known from Japanese Patent Laid-Open No. 53-127991 filed by the same applicant, T+3, and other publications.

In this type of device, the throttle valve is controlled by a negative pressure actuator. For example, negative pressure AC f:'-1
- the diaphragm of the throttle valve is connected to the throttle valve;
Intake manifold pressure is applied to the negative pressure chamber,
The negative pressure chamber is communicated with the atmosphere by turning on or off a negative pressure control valve, and the on/off duty ratio controls the negative pressure in the negative chamber, that is, the diaphragm position corresponding to the negative pressure. However, if the lunoid valve or the circuit that controls it fails, the pressure in the negative pressure chamber cannot be controlled, and the diaphragm position moves to either the forward position or the backward position in response to the pressure in the negative pressure chamber. It is fine if the position to which the throttle valve moves is the position that closes the throttle valve (reduces the engine speed), but if the throttle valve is opened (raises the engine speed) more than before the failure, the accelerator pedal This is extremely dangerous, as the vehicle speed will suddenly accelerate in the same way as if the pedal were pressed all at once.

The first object of the present invention is to provide a vehicle speed control device having a fail-safe function that can maintain a safe running state of the vehicle even in the unlikely event of a failure as described above, and which has a slight improvement over conventional devices. A second object is to provide a vehicle speed control device that can be implemented by simply adding the following components.

In order to achieve the above object, the present invention includes a second control valve (negative pressure release valve) that adjusts the opening degree of the throttle valve, and when a certain vehicle speed higher than the target vehicle speed is reached (second control valve). The control valve is operated to control the throttle valve to close.The second control valve may be of any type as long as it can adjust the pressure in the negative pressure chamber only in the direction of closing the throttle valve.

Generally, the negative pressure actuator of this type of speed control device is
Atmospheric air is introduced through the first control valve (negative pressure control valve).

Switching is performed between shutting off the engine negative pressure, shutting off the atmosphere, and introducing engine negative pressure, but the diaphragm is quickly returned to a specific position (throttle valve closing position) when constant speed driving is canceled. One control valve (release valve) is provided. Therefore, in a preferred embodiment of the present invention, the control valve is utilized as a second control valve.

According to this, it is possible not only to reduce the number of additional elements for carrying out the present invention, but also to effectively utilize the function of another control valve, which was used only when canceling constant speed running.

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

FIG. 1a is a circuit diagram showing one embodiment of the present invention, and FIG. 1b is a negative pressure actuator 100 which is the operating end of the speed control device.
FIG. 1C is a time chart showing the operation of the circuit shown in FIG. 1A.

First, the circuit configuration of the embodiment will be explained with reference to FIG. 1a. 10 is a power supply block, which outputs voltage VB from the battery via the ignition switch swo'l and stabilizes VB by a Zener diode Zl).
Output cc. Reference numeral 20 denotes an F-(frequency-voltage) conversion circuit that converts the frequency of a vehicle speed signal obtained from a reed switch 3, which is opened and closed by a permanent magnet 2 rotating at the same speed as the speedometer cable of the vehicle, into a voltage. 50
stores the voltage corresponding to the vehicle speed voltage signal (actual vehicle speed signal) Vv from the F-■ conversion circuit 20 by operating the set switch SWI, and changes with the vehicle speed voltage signal Vv around the voltage at the time when the storage was performed. This is a memory circuit (target vehicle speed memory means) that outputs a memory voltage signal VM. 55 is a lower limit speed detection circuit that prevents vehicle speeds below a predetermined value (for example, 40 ky'h or less) from being stored, and automatically stores a predetermined vehicle speed when the vehicle speed is low. CMl and CMz are comparators, and a storage voltage signal VM is applied to their inverting input terminals H, and C
A comparison voltage Vx, which is obtained by dividing the voltage Vcc by resistors R1, R2, and Ra, is applied to the non-inverting input terminals of Mt and CM2, respectively.
t and VX2 are applied. The output terminal of CMl is connected to the transistor Qh that drives the solenoid SL1 of the first control valve (negative pressure control valve), and the output terminal of CM2 is connected to the transistor Qh that drives the solenoid SL1 of the first control valve (negative pressure control valve).
The solenoid 5L21 & of the control valve (negative pressure release valve) is connected to the driving transistor Qi via the diode Dg. There is a CM between the non-inverting input terminal and the output terminal of CM2.
A series circuit of a resistor R4 and a diode Df is connected to provide hysteresis to the operation of the second circuit. The base end of the transistor Qi is pulled up by a resistor R5. FF is a flip 70 knob that maintains the setting and release state of constant speed running, and the input terminal is set switch SWI
, IJ zoom switch SW2. Cancel switch S
W3 and brake switch SW4, an open collector output terminal is connected to a non-inverting input terminal of comparator CMI, and another output terminal is connected to the base terminal of transistor Qi via diode Dh.

Next, referring to FIG. 1b, the negative pressure actuator 1 at the operating end is
00 will be explained. Housing 101 is Iota and 101
A diaphragm 102 is held between seven flanges 101a and 101b. Diaphragm 102
A space surrounded by the housing 101a is a negative pressure chamber,
A space surrounded by the diaphragm 102 and the housing 101b communicates with the atmosphere.

A compression coil spring 103 is inserted between the housing 101a and the diaphragm 102, and pushes the diaphragm 102 back to the position of the imaginary line 7 when the pressure in the negative pressure chamber is close to atmospheric pressure. A protrusion 104 fixed near the center of the diaphragm 102 is connected to a link of a throttle valve 105.

An intake manifold 106 is installed in the housing 101a.
Negative pressure intake 107 and atmospheric air intake 108.10 communicating with
9 is an obstacle. A first control valve 110 is a negative pressure control valve, and a second control valve 111 is a negative pressure release valve, both of which are fixed to the housing 101a. The movable piece 112 of the first control valve 110 is tiltable about P as a fulcrum, and has one end connected to a tension coil spring 113, and the other end facing the solenoid SL1. Movable piece 1120
Both ends function as valve bodies, and they open the negative pressure intake port 107 in response to energization and deenergization of the solenoid SL1.

The air intake port 108 is closed (state shown) or the negative pressure intake port 107 is closed, and the air intake port 108 is opened.

The second control valve 111 also has a movable piece 114°, a tension coil spring 115, and a solenoid 8L2f, similar to 110, but the movable piece 114 closes (the state shown in the figure) or opens the air intake port 109. Note that 116 is an accelerator pedal, and 117 is a tension coil spring.

The speed control operation of the embodiment will be described with reference to FIGS. 1a, 1b, and 1c.

The F-V conversion circuit 20 converts the vehicle speed signal into a binary signal whose voltage level changes, removes unnecessary signals due to chattering of the reed switch 3 using a resistor Ra and a capacitor Ca, and applies the signal to the transistor Qa. Transistor Qa
turns on and off in response to the vehicle speed signal, and resistors 1'tb and R
The potential at the connection point c changes accordingly, and when the potential becomes high, a predetermined charge is charged to the capacitor via the resistor Rb, and when the potential becomes low, the charge is discharged via the resistor Rc. The pace and emitter of transistor Qb are biased to the same potential by diodes Da and Db, respectively, and Qb is normally off. When the potential at the connection point between resistor Rb and R,c changes from "low" to "high," the emitter of transistor Qb is biased to a higher potential than its base for a predetermined time determined by the time constant of resistor Rb and capacitor cb. transistor Qb
turns on. Since the collector of transistor Qb is normally at a low potential and becomes a high potential only when Qb is turned on, the collector potential of Qb increases during each cycle of the vehicle speed signal.
The potential remains high for a predetermined time determined by the time constant of bcb. The resulting pulse signal with a constant pulse width is applied to an integrating circuit consisting of a resistor Rd and a capacitor Cc.
The voltage appearing between the terminals of the capacitor Cc is a voltage according to the pulse period, that is, a voltage proportional to the vehicle speed signal,
It passes through transistor Qc and becomes vehicle speed voltage signal Vv.

The memory circuit 50 includes a memory control transistor Qf.

It includes a storage capacitor Cd, field effect transistors (hereinafter referred to as FETs) Qd, Qe, etc.

The drain (or source) of FETQd is connected to the power supply voltage Vc.
A predetermined voltage divided by c f resistors Re, Rf, etc. is applied. On the other hand, when the storage instruction signal (earth level) is not applied, transistor Qf is turned on and F
Since the gate of ETQd is biased to ground level and the voltage is below the hinch-off voltage, the drain of FETQd -
Continuity between sources is broken. When the storage instruction signal is applied, the transistor Qf is turned off, the gate potential of the FET Qd rises, the drain-source of Qd becomes conductive, and the power supply voltage Vcc is applied to one end of the capacitor Cd through the resistors Re and Rf.
A reference voltage Vr divided by voltage is applied, and the capacitor C
Since the vehicle speed voltage Vv is applied to the other end of the capacitor Cd, a charge corresponding to the potential difference IVv-Vrl between the terminals is accumulated in the capacitor Cd. When the memory instruction signal is removed, FgT
Since Qd is turned off again and the input impedance of FETQe is high, one end of the capacitor Cd connected to its gate becomes floating, and the capacitor C
The charge of d is held at the charge immediately before the storage instruction signal is removed, and the potential difference V is also held at the current value of IVv-Vrl (from Q=CV: Q is the charge.

C is capacitance). A voltage of Vv+V is applied to the gate of FETQe, and a corresponding voltage is output from the source end of FETQe as a storage voltage signal VM. The storage voltage signal VM is centered around the voltage VMO immediately after storage,
The value increases as the vehicle speed increases, and decreases as the vehicle speed decreases. Furthermore, since this embodiment is provided with a lower limit speed detection circuit 55, when the vehicle speed decreases to a certain level and the vehicle speed voltage signal vv becomes less than a certain value, the transistor Q
g is turned off and FE is turned off via resistor J and diode De.
The gate of TQd is pulled up to a high potential (Vcc). As a result, conduction occurs between the drain and source of FET Qd, which is related to on/off of transistor Qf, and voltage Vr is applied to one end of capacitor Cd and voltage Vv is applied to the other end. Transistor Qg corresponds to a vehicle speed of 40 b/h. When Vv reaches (rises) a certain voltage, the FET Qd is turned on, and when Vv reaches that voltage, the FET Qd is turned off and the vehicle speed of 40 degrees is automatically stored in the capacitor Cd.

Set switch 5W1i Dume switch 8W2
When turned on, the transistor Qj in the flip-flop FF is turned off, and the cathode side of the diode Dh becomes a high potential H. When the transistor Qj is turned off, the potential xl at the non-inverting input terminal of the comparator CMl becomes the voltage Vcc f
It becomes a predetermined voltage divided by resistors R, 1, R2, and R3,
The potential VX2 at the non-inverting input terminal of comparator CM2 is Vx
It becomes a certain potential higher than t.

When VM (Vx l), the output terminal of the comparator CM1 becomes the Hatake potential H, turns on the transistor Qh't and energizes the solenoid SLI, and when VM>VXI, the output terminal of the comparator CM1 becomes a low potential. The transistor Qh is turned off and the solenoid SLt is deenergized.As will be described later, the vehicle speed is normally controlled so that the VM (Vx2) state is maintained and the output of the comparator CM2 is H. Next transistor Qi
turns on and solenoid SL2 is energized (air intake port 1
09 closed). If the vehicle speed is lower than the target speed, VM<Vxl
-L, solenoid SL1 is energized as described above,
The movable piece 112 of the first control valve fully closes the atmosphere intake port 108 and fully opens the negative pressure intake port 107, as shown in FIG. 1b. As a result, the pressure in the negative pressure chamber gradually decreases, and the diaphragm 102 moves in a direction to reduce the volume of the negative pressure chamber, increasing the opening degree of the throttle valve 105 connected to the diaphragm 102 via a protrusion 104 or the like. and increase the vehicle speed. Also, if the vehicle speed is higher than the target speed, VM) V
x t, the solenoid S L 1 is deenergized as described above, and the movable piece 112 closes the negative pressure intake 107 and opens the atmospheric intake 108 . As a result, the pressure in the negative pressure chamber gradually approaches atmospheric pressure, and accordingly, the diaphragm 102 is pushed back by the force of the compression coil spring 103, and the opening of the throttle valve 105 is completely reduced to reduce the vehicle speed. In actual control, the vehicle travels at a speed approximately equal to the target vehicle speed, resulting in the VM cow Vxt.
As shown in Figure c, the storage voltage signal VM slightly includes ripples of the vehicle speed signal, and the voltage VM always fluctuates with the cycle of the vehicle speed signal. Therefore, the output signal of the comparator CM1 becomes a pulse signal with the same period as the vehicle speed signal, and when there is a change in the average value of the memory voltage signal VM (change in vehicle speed), the pulse width (duty ratio) of the pulse signal changes. The on/off duty ratio of transistor Qh changes accordingly. Transistor Qh on, i.e. solenoid SL
If the ratio of the period in which transistor Qh is energized to shut off the atmosphere and introduce negative pressure to the period in which transistor Qh is turned off, that is, the period in which solenoids 8T and 1 are deenergized to introduce atmospheric air and shut off negative pressure, changes will occur in the negative pressure chamber. The pressure corresponds to this, the position of the diaphragm 102 changes accordingly, and the opening degree of the throttle valve 105 changes accordingly.

However, if a situation such as the movable piece 112 being caught somewhere occurs, the atmosphere will continue to be introduced into the negative chamber, or negative pressure will continue to be introduced into the negative pressure chamber. In the former case, the pressure in the negative pressure chamber becomes the same as atmospheric pressure, and the diaphragm 102 is pushed back by the spring 103, which closes the throttle valve 105 and reduces the engine speed and vehicle speed, which is safe; however, in the latter case, it is safe. When the pressure in the negative pressure chamber drops extremely, diaphragm 1
02 fully opens the throttle valve 105, so the vehicle speed rapidly increases. However, when the vehicle speed exceeds a certain value, VM
) Vx 2, and the output terminal of comparator CM2 becomes H.
changes from low to low, lowering the base potential of transistor Qi and turning off Qi, so solenoid SL2 is deenergized.
The movable piece 114 of the second control valve 111 is connected to the spring 115
, the air intake port 109 is opened and air is introduced, so the pressure in the negative pressure chamber increases and the diaphragm 1
02 and reduce the opening of the throttle valve 105.
Automatically reduce vehicle speed. Vehicle speed becomes abnormally high and VM:
> If a state where Vx z occurs even for a short period of time,
When the output terminal of comparator CM2 becomes L (earth level), current flows to the output terminal side via resistor R4 and diode Dfi, which is equivalent to connecting resistor R4 in parallel to a series circuit of resistors R2 and R3. As shown in FIG. 1c, the potential of VX2 is lowered, so even if the voltage of VM slightly decreases due to the ripple contained in the storage voltage signal VM,
Comparator CM2 is never inverted again.

Cancel switch SW3 or brake switch''-
When 8W4 is turned on, flip-flop FF' is inverted, internal transistor Qj is turned on, and the potential of Vxi is reduced to 0 [
■). In this state, since VM>0[:V:l, the output terminal of the comparator CMI is held at L, the transistor Qh'Th is turned off, and the solenoid 5L1f is constantly de-energized, so that the negative output terminal is set to the atmosphere introduction/negative pressure cutoff state. state.

At this time, the cand side of the diode Dh is set to L by the flip 70 knob I''F, so the base potential of the transistor Qi decreases, Qi is turned off, the solenoid 8L2 is deenergized, and the atmospheric air intake port 109 is opened. Therefore, the two atmospheric air intake ports 108 and 109 open, the pressure in the negative pressure chamber rapidly approaches atmospheric pressure, the diaphragm 102 returns, the throttle valve 105 closes, and the vehicle speed control is canceled. In the above, a superimposed vehicle speed voltage signal corresponding to the actual vehicle speed and a target vehicle speed signal as a memory voltage signal is compared with a comparison voltage xl which is a fixed value signal, but the actual vehicle speed signal and the target vehicle speed signal are compared. The negative pressure control valve 110 may be controlled according to the result.In such a case, one end of the capacitor Cd1 of the memory circuit 50 is grounded, and the other end is connected to the output end of the vehicle speed voltage signal. If the connection is made through the vehicle speed voltage signal, the stored output will be a certain constant value, and this can be compared with the vehicle speed voltage signal.

FIG. 2a shows a circuit configuration of another embodiment of the present invention. In this embodiment, most of the speed control is performed by the microcomputer CPU. The vehicle speed signal from reed switch 3 is connected to resistor Ra and capacitor C.
The transistor Q passes through the chattering removal circuit consisting of a.
Switch a. The pulse signal of the output of Qa is CP
It is applied to input port P3 of U. Set switch SW
I.

Resume switch 8W2. Cancel switch 8W3
and brake switch SW4 are respectively input to the CPU input port P7. P6. Connected to Ps and PA. In the embodiment described above, the ripple component of the F-■ conversion output from the vehicle speed signal was used to control the duty of the solenoid '8Ls, but in this embodiment, F-V conversion is not performed, so a sawtooth wave is generated. Oscillator 08C1&: is used to perform duty control. Output port PA for 8 bits of CPU is 8 bit D/A converter DA
The analog signal output terminal of the DAC is connected to the non-inverting input terminal of the comparator CMI, and the output signal Vo of the oscillator O8C is connected to the inverting input terminal of the comparator CMI.
sc is applied. Transistor Qj is a transistor that prohibits transistor Qh from turning on, and is connected to output port Pl of the CPU. Transistor QI that drives solenoid SL2 is connected to output port P2.

Note that the negative pressure actuator shown in FIG. 1b is also used in this embodiment. Referring to Figure 2b, oscillator 08C, D/A converter DAC, comparator CMI
, ) The operation of transistors Qh and Qj will be explained.

The oscillator O8C always outputs a sawtooth wave voltage Vosc. When predetermined data is output to PA (output capo), D
/A converter DAC outputs an analog voltage Vxt (z) corresponding to the data. During the period of Vxl, > Vosc, the output terminal power of comparator CMt H1vXl<Vosc
) period nJ[CMl(D) If the output i becomes L and the output port Pl is L and the transistor Qj is off, then 0Ml
Transistor Qh turns on in response to 1(・L) at the output terminal.
When off t, , Qh is on, solenoid 8L1 is energized, and when Qh is off, solenoid 8L1 is deenergized. The on/off duty ratio of the transistor Qh is determined by the digital data output to the output port PA.

An example of the processing flow of the microcomputer CPU will be described with reference to FIG. 2C. Immediately after the power is turned on, the initial state is set so that constant speed control is not performed.
Output Lf to I to H port P2, turn off transistor Qh, turn off Qi'e, and turn off two control valves 110.11.
1 controls the negative pressure chamber to communicate with the atmosphere. Next, check Ps and P7 and press set switch S.
Wait until WI or resume switch SW2 is turned on. When the input port P6 becomes L, it is determined that SW2 is turned on, and the register R1f is checked to determine whether the vehicle speed has been previously stored. If it is not stored, the initial data in the ROM (read-only memory) is 2 and stores it in register R1. (in capo)
When P7 becomes L, it is judged that SWl is turned on, and BO) P
a Check 2 to detect the cycle of the vehicle speed signal. This starts counting when port P3 reverses from H to L (or from L to H), and then when port Ps changes from H to L.
(or from 1. to H) is taken as one cycle of data. This periodic data is stored in register R1.
(vehicle speed memory). In order to convert the cycle data stored in the register R1 into data for setting the voltage VXI, which determines the duty ratio of energization/deenergization of the solenoid SLI necessary to obtain the vehicle speed corresponding to the cycle, the data is stored in the ROM in advance. The data corresponding to the value of register R1 is read out by referring to a table provided therein, and the data is stored in register R2. Baud the data in register R2,
output to PA, and causes the D/A converter DAC to generate a predetermined voltage Vx+i. baud) Pt and outputs 11 to P2, respectively. This turns off transistor Q, and Q
Since i is turned on, the transistor Qh repeatedly turns on and off at a predetermined duty, and at the same time controls the duty of the N V node 8Lxi, SL2 is energized, and the negative pressure actuator 100 changes the opening degree of the throttle valve 105 according to the duty ratio. Set all settings. Next, cancel switch 8W3. Processing is performed to check the playback switch SW4 and maintain the vehicle speed at a constant speed, but since the latter process takes time, the boat P4. Vehicle speed processing is performed only once every N times P5 is read. The number of times N is registered in register R3.
Store boat P4. P5 and the contents of register R3 are checked, and the contents of register R3 are decremented by one (-1). When the cancel switch 5W3t or the brake switch SW4 is turned on and the boat P4 or P5 is pushed to L, it returns to 1 starbi. When the value of register R3 becomes 0, the boat Ps f is checked and the period of the vehicle speed signal is counted, and the period data obtained as a result is stored in register R4.
Store in. Periodic data when storing vehicle speed is in register R1
Since the stored vehicle speed is stored in the register R1, the contents of the register R1 corresponding to the stored vehicle speed are compared with the contents of the register R4 corresponding to the current vehicle speed. If R1=R4, the current vehicle speed matches the memory vehicle speed, so return to ■ and return to BO) P4. P5 is checked and register R3 is compared and decremented. If R1=R4, the difference between the contents of register R,1 and register R4, that is, the difference between the stored vehicle speed and the current vehicle speed, is stored in register R5. Here, it is checked whether the current vehicle speed is abnormally higher than the stored vehicle speed. M
is data indicating the upper limit, for example, M is R1 and R4 when the current vehicle speed exceeds the stored vehicle speed by 20%.
The value corresponding to the difference between If Rs>M, the current vehicle speed is too high, so it is considered abnormal and L is output to boat P2.
Transistor Qi is turned off, solenoid 8L21&: is deenergized, and air intake port 109 is opened. If an abnormality occurs, turn off) P4. Check P5 repeats the vehicle speed check. If an abnormality occurs, the value of M is updated to 0, and L continues to be output to the boat P2 unless the current vehicle speed or the stored vehicle speed decreases. By opening the atmosphere intake port 109, the negative pressure actuator 100 is deenergized, the opening degree of the throttle valve 105 is reduced, and the vehicle speed is reduced to the memorized vehicle speed. 1
Close 09. If there is a slight difference between the current vehicle speed and the stored vehicle speed (Rs≦M), refer to the table provided for correcting the vehicle speed, read the data corresponding to the contents of register R5 from the table, and use that data. It is added to the value of register R2 and the added value is stored in register R2. Outputs the value of register R2 to PA (baud) and outputs it to D/
Update the output voltage VXl of the A converter DAC, adjust the vehicle speed so that it approaches the stored vehicle speed, and return to step (3). In the above embodiment, when the vehicle speed becomes abnormally high, the second control valve 111 is opened until the vehicle speed decreases to the target vehicle speed, and when the target vehicle speed and the current vehicle speed become equal, the control valve 111 is closed to maintain a constant speed. Although we try to continue control, there is a possibility that the failure of the first control valve 110 will not be resolved in a short time, and in such a case, the vehicle will repeat acceleration and deceleration, so if an abnormality occurs, The constant speed control may be canceled and the second control valve may be controlled so as not to be closed again.

As described above, according to the present invention, even if an abnormality occurs in the valve that controls the vehicle speed, the vehicle speed will not rise above a certain value and it will be safe.

[Brief explanation of the drawing]

1a, 1b and 1c show an embodiment of the vehicle speed control device of the present invention, FIG. 1a is an electric circuit diagram showing the configuration of the control circuit, and FIG. 1b is a negative pressure actuator 10.
FIG. 1C is a block diagram showing the configuration of 0 and its surroundings, and is a time chart of the circuit shown in FIG. 1A. 2a, 2b and 2c show another embodiment of the present invention, FIG. 2a is a block diagram showing the circuit configuration of the embodiment, and FIG. 2b is a time chart showing the operation of the circuit. FIG. 2C is a flowchart showing an example of the processing flow of the microcomputer CPU. 2: Permanent magnet 3: Reed switch 10: Power supply
20: F'-V conversion circuit 50: Memory circuit
55: Lower limit speed detection circuit 100: Negative pressure actuator 101; Housing 102; Diaphragm 103
, 113.115.117 Nispring 105:
Throttle valve 106: Intake manifold 1
07: Negative pressure intake 108.109: Atmospheric intake 1
10: First control valve (negative pressure control valve) 111: Second control valve (negative pressure release valve) 112.114: Movable piece 116: Accelerator pedal C
MI, CM2: Comparator Figure 2a Figure 2b

Claims (5)

[Claims] (1) Equipped with a negative pressure control valve, a negative pressure release valve, a negative pressure control solenoid that controls the negative pressure control valve, and a negative pressure release control solenoid that fully controls the negative pressure release valve, and is connected to the throttle valve to control its opening. Negative pressure actuator that controls; Actual vehicle speed signal generation means that generates an actual vehicle speed signal; Target vehicle speed storage means that stores the target vehicle speed in response to switch operation; Energizes the negative pressure control solenoid according to the actual vehicle speed and target vehicle speed. and, depending on the actual vehicle speed and target vehicle speed, electrically energizes or deenergizes the negative pressure release control solenoid in the direction of closing the throttle valve when the actual vehicle speed or target vehicle speed exceeds the set amount or more. High-speed restraint means; Complete vehicle speed control system. (2) The constant speed control means includes a comparator that compares the vehicle speed signal obtained by superimposing the actual vehicle speed signal and the target vehicle speed signal with a constant value signal and generates a binary signal corresponding to the high/low correlation between the two, and a negative pressure control solenoid. The vehicle speed control device according to claim 1, wherein the vehicle speed control device is a switching element that is connected and turned on and off by the binary signal. (3) The high speed suppression means includes a comparator that compares a vehicle speed signal in which the actual vehicle speed signal and target vehicle speed signal are superimposed with a fixed value signal and generates a binary signal corresponding to the high/low correlation between the two, and a negative pressure release control solenoid. The vehicle speed control device according to claim 1, which is a switching element that is connected and turned on and off by the binary signal. (4) The vehicle speed control device according to claim (3), wherein the switching element is further biased on or off in the direction of closing the throttle valve in response to a signal indicating depression of the brake. (5) The vehicle speed control device according to claim (1), wherein the target vehicle speed storage means and the high speed suppression means are microprocessors.