JPH01145237A - Constant speed traveling device - Google Patents

Abstract

PURPOSE:To prevent the car speed hunting by suspending the duty-ratio control of an actuator means for the constant speed traveling control when the difference between a memorized car speed and a traveling car speed is less than a prescribed value or the absolute value of the accelerating speed is less than a prescribed value. CONSTITUTION:In the constant speed traveling control, a CPU compares the car speed (traveling cart speed) at present and a car speed (memorize car speed) memorized as a set car speed which is detected by a car speed sensor (lead switch SW2) during the turning-ON operation of a set switch SW4. The opening degree of a throttle and a vent valve V2 so that the difference becomes zero. In this case, if the difference between the memorized car speed and the traveling car speed is less than a prescribed value or the absolute value of the accelerating speed is less than a prescribed value, duty ratio control is suspended. Said prescribed value is set to a value over the insensitive range of each valve V1, V2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a constant speed traveling device that stores the speed of a vehicle and automatically maintains the vehicle at the memorized speed. This relates to a constant speed traveling device.

[Prior Art] Generally, this type of constant speed traveling device compares the stored vehicle speed with a virtual vehicle speed using a vehicle speed detection means and a storage means for storing the speed of a traveling vehicle traveling at a constant speed, and eliminates the vehicle speed deviation. By controlling the duty ratio of the actuator means in the direction, the control valve and the vent valve are turned on and off, and the control valve and the vent valve are turned on and off.
By repeating the off-state, negative pressure is supplied to the actuator, and the actuator controls the opening degree of the throttle valve.

FIG. 16 shows the control output characteristics of the control valve and vent valve of this type of constant speed traveling device.

In the above-mentioned constant speed traveling device, when the constant speed traveling control is controlled by the duty ratio using the control valve and the vent valve, when the vehicle speed deviation between the stored vehicle speed and the virtual vehicle speed decreases, the ON time of the control valve or the vent valve becomes shorter.

The control valve or vent valve has a response characteristic as shown in FIG. 17, and when the vehicle speed deviation decreases and the on-time of the control valve or vent valve becomes shorter, the on-time within the dead band is indicated. It turns out.

In the dead zone shown in Figure 17, even if you instruct the control valve or vent valve to turn on, the control valve or vent valve is not within the range in which it can respond, so the control valve or vent valve cannot be turned on. There was a problem that hunting occurred in the vehicle speed.

Therefore, the technique disclosed in Japanese Unexamined Patent Publication No. 157831/1983 solves this problem.

That is, a vehicle speed detection means, a storage means for storing the speed of a vehicle traveling at a constant speed, an actuator means for controlling opening and closing of a throttle valve, and a direction for comparing the stored vehicle speed with a virtual vehicle speed and eliminating the vehicle speed deviation. An electronic control circuit for controlling the duty ratio of the actuator means is disposed at the end, and when the duty ratio for controlling the actuator means is below a predetermined value, the duty ratio control is stopped and the stopped duty ratio control amount is integrated. However, when the integral value reaches an arbitrary value, a duty ratio for controlling the actuator means is determined in accordance with that value.

Therefore, if the vehicle speed deviation is small when driving at a constant speed,
The actuator means that controls the opening and closing of the throttle valve is brought into a stopped state, and the duty ratio control amount of the actuator means that controls the duty ratio in a direction to eliminate the vehicle speed deviation during the stopped period is integrated, and the integrated value is an arbitrary value. Since the actuator means is controlled in accordance with the integral value when the vehicle speed is reached, hunting will not occur in the vehicle speed even if the vehicle speed deviation between the stored vehicle speed and the virtual vehicle speed is small.

[Problems to be Solved by the Invention] However, the virtual speed divided by the electronic control circuit includes noise from the vehicle speed detection means that detects the current vehicle speed, the signal processing process, etc. Even if the actual acceleration is constant and the actual acceleration is zero, there may be cases where the calculated acceleration does not become zero. For this reason, if control is performed using a virtual vehicle speed calculated from the vehicle speed and acceleration at the time of measurement, it is predicted that the actuator means will be driven by noise when the vehicle is in a running state where it does not originally need to be driven.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a constant speed traveling device that can control the vehicle speed without causing any hunting during constant speed traveling.

[Means for Solving the Problems] The constant speed traveling device according to the present invention includes a vehicle speed detection means for detecting the current vehicle speed, a storage means for storing the speed of the traveling vehicle traveling at a constant speed, and a control for opening and closing of a throttle valve. The duty ratio of the actuator means is controlled in a direction to eliminate the vehicle speed deviation based on the stored vehicle speed and the calculated vehicle speed and acceleration, and the vehicle speed deviation between the stored vehicle speed and the vehicle speed is less than or equal to a predetermined value. or when the acceleration is below a predetermined value, the electronic control circuit stops the duty ratio control.

[Function] In the present invention, in normal constant speed running control, the vehicle speed detected by the vehicle speed detection means is used to calculate the stored vehicle speed of the storage means for storing the speed of a traveling vehicle traveling at a constant speed and the stored vehicle speed. The duty ratio of the actuator means is controlled in a direction that eliminates the vehicle speed deviation based on the vehicle speed and acceleration obtained.

When the vehicle speed deviation between the stored vehicle speed and the vehicle speed is below a predetermined value, or when the acceleration is below a predetermined value, the duty ratio control is stopped to prevent the actuator means from being driven by noise. .

[Example] Hereinafter, an example illustrating an example of the above technical means will be described.

FIG. 1 shows an overall configuration diagram of a constant speed traveling device according to an embodiment of the present invention.

In this configuration, the electronic control circuit CPLJ is composed of a single-chip microcomputer, and includes a reed switch SW2 that detects a vehicle speed signal, a clutch switch SW3 that detects depression of a clutch (not shown), and depression of a brake (not shown). Brake switch S that detects
W6, set switch SW4, resume switch SW
The output of 5 is input. Further, a vacuum pump BP generates a negative pressure that operates a negative pressure actuator AC that controls the opening degree of the throttle valve S■, and the output of a vacuum switch SW7 disposed in a surge tank ST that stores the negative pressure is inputted.

Here, the resume switch SW5 restarts the -H canceled constant speed driving control at the updated and stored controlled vehicle speed, and the clutch switch SW3 and the brake switch SW6 are constant speed driving control cancel switch means. be.

A permanent magnet PM connected to a speedometer cable (not shown) is arranged near the reed switch SW2, and when the permanent magnet PM rotates as the vehicle moves,
The contacts of the reed switch SW2 open and close, and a pulse (vehicle speed signal) with a frequency proportional to the vehicle speed is sent to the electronic control circuit CPU. Note that the reed switch SW2 and the permanent magnet PM connected to the speedometer couple constitute vehicle speed detection means for detecting the current vehicle speed.

The clutch switch SW3 opens and closes in conjunction with the vehicle's clutch pedal, and the brake switch SW6 opens and closes in conjunction with the vehicle's brake pedal. Brake switch SW6
A stop lamp L is connected to the brake switch SW6, and the stop lamp L lights up when the brake switch SW6 is turned on (closed).

The set switch SW4 and the resume switch SW5 are push button switches, and are arranged at positions that are easy for the driver to operate. By pressing the set switch SW4, the vehicle speed is memorized and constant speed driving control is started.
Although constant speed driving is canceled by pressing the brake switch SW6, the memorized vehicle speed remains. When the resume switch SW5 is pressed, constant speed driving control is started at the memorized vehicle speed before constant speed driving was canceled.

Note that power is supplied to the brake switch SW6 via the fuse F, and power is supplied to the electronic control circuit CPU via the power switch SW1.

The output of the electronic control circuit CPU is to drive the solenoid of a control valve V1 that controls a negative pressure actuator AC, which will be described later, via a drive circuit D1, the solenoid of a vent valve v2 via a drive circuit D2, and the solenoid of a release valve V3. They are connected to each other via circuit D3.

It is connected to the motor of the vacuum pump BP and the like via a drive circuit D4.

The negative pressure actuator AC is configured as follows.
Operate.

The negative pressure actuator AC constitutes a negative pressure chamber A1 sealed by a diaphragm A4 disposed within the housing A5, and the opposite side of the diaphragm A4 is an atmospheric side A2. The diaphragm A4 is energized by a compression coil spring A3 disposed on the negative pressure ff1A1 side.

By the way, the diaphragm A4 is the throttle valve Sv.
A throttle rod B1 is connected to open and close valve B2.

Further, in the negative pressure chamber A1 of the negative pressure actuator AC,
Negative pressure from the surge tank ST is introduced through a control valve V1, a vent valve v2, and a release valve v3.

The control valve v1 sends the negative pressure of the surge tank ST to the negative pressure actuator means when the solenoid is energized, and shuts it off when the solenoid is not energized. Furthermore, when the solenoid is in an energized state, the vent valve v2 sends out the negative pressure sent from the control valve v1 side to the negative pressure actuator AC side, and when its solenoid is in a non-excited state, it sends out the negative pressure on the negative pressure actuator AC side. Emitted into the atmosphere. When an abnormality occurs in the control system and proper control becomes impossible, the release valve V3 discharges the negative pressure in the negative pressure chamber A1 of the negative pressure actuator AC to the atmosphere, increasing the negative pressure chamber A1. This is to create an atmospheric pressure state. At this time, the throttle valve Sv is connected to the throttle rod B1.
is pushed back to close valve B2. Normally, the solenoid of the release valve v3 is in an excited state, and the vent valve v2 and the negative pressure chamber A1 of the negative pressure actuator AC are in communication.

The control valve (1) and the vent valve (2) are controlled in duty ratio by an electronic control circuit CPLI. That is, during constant speed driving control, the electronic control circuit CPU
The stored vehicle speed is compared with the vehicle speed at that time, and the duty ratio of the signal that excites the solenoids of the control valve V1 and vent valve V2 is controlled so that the difference between the two becomes equal. For example, when deceleration is required, control valve 1 is turned off, the duty ratio of vent valve v2 is controlled, and the proportion of time that atmospheric air is communicated with negative pressure actuator AC is controlled, and the diaphragm A4 is used to control the thrower valves 1 to 1. Close SV. Conversely, when acceleration is required, turn on vent valve ■2 and turn on control valve v1.
The throttle valve S■ is opened by controlling the duty ratio and controlling the proportion of time for sending negative pressure to the negative pressure actuator AC.

Next, the operation of the microcomputer of the electronic control circuit CPU will be explained using the flowcharts of the constant speed running control operation shown in FIGS. 2 to 12 and the flowchart of FIG. 13 showing another example of the constant speed running control operation. . In addition, FIG. 14 is a control characteristic diagram of the vehicle speed deviation used for calculating the valve-on time of the constant speed traveling device of the embodiment shown in FIG. 1, and FIG.
FIG. 4 is a control characteristic diagram of acceleration used for calculating the valve-on time of the constant speed traveling device of the embodiment shown in the figure.

When the power switch SW1 of the electronic control circuit CPU of this embodiment is turned on and this program is started, the memory is initialized in step 1. At this time, the "standby state control flow" of the control state S=O of the control state branch program is set. In step 2, the states of each switch SW2 to SW7 are read.

Step 3 is a branching step in which the control state S is determined and a corresponding processing function is selected.

That is, this program branches according to each control state,
Since it is programmed to function according to the branched program, the control state S is specified for each function and the flow processing of each control state is started.

Since the control state S=0 is set in step 1, the "standby state control flow" with S=0 is entered in step 3.

Control state S=O: "Standby state control flow" In this flow, the operating state of the resume switch SW5 is detected,
Put the control system into cancel state.

When entering this flow, first, in step 01, all valves are
That is, control valve ■1 and vent valve ■2,
The release valve (3) is turned off, the control of the negative pressure actuator AC is stopped, and the constant speed running control is stopped.

Then, in step 02, the operating state of the resume switch SW5 is detected. Step 0 when turned on
Check the memorized vehicle speed in Step 3, and if the memorized vehicle speed is not 0KIIt/h (clear state), in Step 04, the control state S=1 is changed to "
Further, in step 05, a vacuum pump flag is set to activate the vacuum pump BP (set to "Htt").

That is, preparations are made to enter the "full-on control flow" in the control state S=1.

Furthermore, when the resume switch SW5 is not turned on or when the stored vehicle speed is 0K11/h (clear state), the control state S is not changed because the resume function is denied.

Control state S=1: F full-on control flow" This flow performs prospective control in order to quickly drive the negative pressure actuator AC to a predetermined position. That is, in the "deceleration control flow" of control state S=4, control valve v1 is off, and negative pressure actuator A
The pressure in the negative pressure chamber A1 of AC is decreasing, and the "standby control flow" is when the main constant speed running control is entered or after the "cancellation control flow", so the negative pressure of the negative pressure actuator AC is reduced. Since the negative pressure in the pressure chamber A1 does not match the set speed, even if you restart the constant speed running control and control the duty ratio of the control valve v1, the predetermined throttle opening will not be reached immediately. This is because it is not possible. Therefore, in step 11, it is determined whether this flow is entered for the first time, and when it is entered for the first time, all valves VL V2 and V3 are turned on in step 12, and in step 13, it is set in advance to lengthen in proportion to the vehicle speed. Set full-on control time. After entering this flow in step 11 and setting the full-on control time, step 14
Check the progress of the full-on control time set in . When the full-on control time has elapsed, first, in step 15, the control valve V1 is turned off, and in step 16, the control state S is turned off.
= 2 and enters the "constant speed control flow".

Control state S=2: li "Constant speed control flow" This flow is a flow for performing constant speed driving at the stored vehicle speed.

In step 201, it is determined whether the vehicle speed measurement timing has arrived, and when it is the vehicle speed measurement timing, the vehicle speed is measured in step 202. If it is not time to measure vehicle speed, step 2
In step 03, the rise timing of the duty ratio for controlling the duty ratio of the negative pressure actuator is determined. Once the start-up timing of the duty ratio control is determined, the vehicle speed is calculated in step 206. Car speed calculation is step 202
This is the vehicle speed value V calculated based on the value obtained by measuring the vehicle speed at , that is, reading the value of the vehicle speed detection means that detects the current vehicle speed. Further, in step 207, acceleration a is calculated. In step 208, a virtual vehicle speed Vi is calculated based on the vehicle speed calculation in step 206 and the acceleration calculation in step 207.

The virtual vehicle speed Vi calculation is expressed as follows.

■i=v+a-℃ Iro, Vl is virtual vehicle speed, ■ is the vehicle speed calculated by vehicle speed calculation, a is the acceleration calculated by acceleration calculation, Kt is compensation time, It is.

The compensation time Kt is set based on the time delay between the vehicle speed measurement timing and the output for controlling the duty ratio of the negative pressure actuator.

In step 209, the vehicle speed deviation Vd is obtained by subtracting the virtual vehicle speed Vi from the stored vehicle speed MV. In step 210, it is determined whether the absolute value of the vehicle speed deviation vd obtained in step 209 is less than or equal to a predetermined vehicle speed deviation V[m/h or less, that is, VL=0.5, When, step 21
1 sets the vehicle speed deviation ■d to zero. Also, step 2
In step 212, the absolute value of the acceleration a obtained in step 07 is determined as a predetermined acceleration a [hereinafter, that is, aL = 0.5 Km/h/
s or less, and determine whether the predetermined acceleration a [when below,
In step 213, the vehicle speed deviation Vd obtained by setting the acceleration a to zero is determined. Vehicle speed deviation V divided in step 209
d, or if it is confirmed in step 210 that the vehicle speed deviation is not less than the predetermined vehicle speed deviation VL, and furthermore, it is confirmed in step 212 that the acceleration a calculated in step 207 is not less than the predetermined acceleration aL, the acceleration calculated in step 209 is The vehicle speed deviation Vd is used as is.

Note that the predetermined vehicle speed deviation V[ is a vehicle speed deviation corresponding to the dead zone of the valve, and the predetermined acceleration a[ is a region set based on the noise frequency and noise distribution.

Then, in step 214, the valve control time V of the control valve V1 and vent valve ■2 is calculated from the vehicle speed deviation ■d.
Divide CTL. That is, the duty ratio for opening and closing the control valve V1 and the vent valve V2 is determined.

The valve control time is the time required to switch the state of the valve from on to off or from off to on when controlling the duty ratio of the valve. At this time, the valve control time VCTL is obtained by multiplying the vehicle speed deviation Vd by the ratio measurement r&G. Note that the proportionality constant G gives a relationship between the vehicle speed deviation Vd and the amount of acceleration/deceleration caused by opening and closing of the throttle valve SV controlled by the negative pressure actuator AC.

Note that the processing from step 208 to step 214 may be performed as shown in the flowchart of FIG. 13.

That is, in step 206, the vehicle speed V is calculated, and in step 20
After calculating the acceleration a in step 7, the vehicle speed deviation Vd is obtained by subtracting the vehicle speed V from the stored vehicle speed IVlv in step 250.

Then, in step 251, it is determined whether the absolute value of the vehicle speed deviation Vd is less than a predetermined vehicle speed deviation [hereinafter, for example, VL=0.5 m/h, and the predetermined vehicle speed deviation VL=0.5Km
/h or less, the vehicle speed deviation Vd is set to zero in step 252. Next, in step 253, the absolute value of acceleration a is less than or equal to a predetermined acceleration at, for example, aL = 0.5Km.
/h/s or less, the acceleration a is determined to be less than or equal to a predetermined acceleration a, and the acceleration a is set to zero in step 254. In step 255, an acceleration compensation value, which is the product of acceleration a and compensation time of 1, is subtracted from vehicle speed deviation Vd. And furthermore,
Multiply by the proportionality constant G to find the valve 1ilJ control time VCTL.

Next, in step 215, it is determined whether the valve control time VCTL for controlling the duty ratio of the valve is positive. If positive, in step 216, the control valve v1 and the vent valve 2 are turned on. When the value is negative or zero, control valve (1) and vent valve (2) are turned off in step 217.

Further, when it is not the rise timing of the duty ratio for controlling the duty ratio of the negative pressure actuator AC in step 203, check whether the valve control time VCTL for controlling the duty ratio has ended in step 204, that is, the valve control time from the rise time of the duty ratio control. Determine whether time equal to VCTL has elapsed and calculate valve control time VCT
When L is completed, control valve V1 is turned off and pen 1 to valve V2 are turned on in step 205. Furthermore, if the valve control time V CTL for controlling the duty ratio has not ended in step 204, the current valve state is continued.

When the resume switch SW5 is turned on for a predetermined time (here, 0.5 seconds) or more in step 218, step 2
In step 19, the "acceleration control flow" with control state S=3 is set.

Then, when the set switch SW4 is turned on in step 220, the "deceleration control flow J@" of the control state S=4 is set in step 221.The clutch switch SW3 is turned on in step 222, and the control state S is set in step 223.
=1 or S=2 to determine whether it is necessary. In other words, since the clutch switch SW3 has a resume function,
It is determined whether this flow is entered from either the "acceleration control flow" or the "deceleration control flow", and when the flow is entered from either of the two flows, the "clutch resume" control state of control state S=6 is determined in step 224. If not, in step 225, the "cancellation control flow" of the control state S=5 of the cancel function is set as the clutch switch SW3 is turned on.

When the brake switch SW6 is turned on in step 226, a "cancellation control flow" with control state S=5 is set in step 227. In steps 228 and 229, the low speed limit is determined, and if the virtual vehicle speed Vi is below the predetermined control vehicle speed, the control state S=7 is set and constant speed driving control is prohibited.

Then, in step 230, a "vacuum pump control subroutine" process is entered.

Control State S=3: II' Acceleration Control Flow This flow is a flow for accelerating the vehicle during constant speed driving control and updating the constant speed driving speed.

First, in step 31, all valves, that is, control valve 1, vent valve V2, and release valve 3, are turned on, the negative pressure of the negative pressure actuator AC to A1 is increased, and the throttle valve SV is opened, and step 32 The speed is accelerated until the resume switch SW5 is turned off. When the resume switch SW5 is turned off, a "constant speed control flow" with control state S=2 is set in step 33,
The vehicle speed at that time is stored in the memory in step 34.

Control state S=4; l' deceleration control flow" This flow is a flow for decelerating the controlled vehicle speed during constant speed driving control and restarting constant speed driving control. When turned on, the control state becomes S=4, and this "deceleration control flow" is entered. In step 41, it is determined whether either clutch switch SW3 or brake switch SW6, which has a cancel function, is on, and if either one is on, all valves ■1, V2, and ■3 are turned off in step 42. As a result, constant speed driving control is stopped after entering the "deceleration control flow". When neither clutch switch SW3 nor brake switch SW6 is turned on in step 41,
In step 43, control valve (1) and vent valve (v2) are turned off, and release valve (v3) is turned on.

In this way, when the negative pressure supply from the negative pressure actuator AC is cut off, the throttle valve S2 gradually closes, and the vehicle speed gradually decreases. In step 44, it is detected that the Sera 1 switch SW4 is turned off, and in step 45, the vehicle speed at the time when the set switch SW4 is turned off is stored. Then, in step 46, unless either the clutch switch SW3 or the brake switch SW6, which has a canceling function, is turned on and exits from the constant speed driving control, the control state S=1 is set in step 48, and "full-on" is set. into the control flow. That is, the deceleration control continues while the Sera 1 switch SW4 is turned on, and constant-speed running is resumed at the vehicle speed at the time when the set switch SW4 was turned off. When either the clutch switch SW3 or the brake switch SW6 is turned on in step 46, the control state S=5 is set in step 47, and a "cancellation control flow" is entered. If the set switch SW4 is turned on in step 44, the vacuum pump flag is set (set to "HWe") in step 49.

Control state S=5: If cancel control flow" This flow is performed when the clutch switch SW3 or brake switch SW6 is
When turned on, constant speed driving control is canceled. When the clutch switch SW3 or brake switch SW6 having a cancel function is turned on in step 51, the "standby state control flow" with control state S=O is selected in step 52, and in step 53 all valves V1, V
2. Turn off V3.

Control state S=6: Ir clutch resume control flow" In this flow, during the processing of the "constant speed control flow" in control state S=2, clutch switch SW3 is turned on, and the constant speed running control is canceled at -1. This is the flow for entering constant speed driving control again.

First, in step 61, all valves V1, 2, and V3 are turned off, and when it is determined in step 62 that the clutch switch SW3 is turned off, in step 63, the "full-on control flow" is started with the control state S=1. to go into.

Control state S=7: "Low speed limit control flow" This flow is for canceling and clearing the stored speed when the vehicle speed is lower than a predetermined speed in steps 228 and 229. In step 71, the stored vehicle speed MV is cleared, in step 72, all valves ■1, ■2, and V3 are turned off, and in step 73, the "standby state control flow" of control state S-0 is entered.

The above is an explanation of each control state flow.

In addition, by driving the vacuum pump BP, the surge tank S
The "vacuum pump control subroutine" for accumulating and maintaining a predetermined negative pressure in T is not directly related to the gist of the present invention, and therefore its description will be omitted.

As described above, in the constant speed traveling device of the present invention, the virtual vehicle speed Vi is obtained from the pulse of the reed switch SW2 during constant speed traveling, and the controller 1 to the roll valve V1 and the vent valve v2 are controlled from the memorized vehicle speed Mv for constant speed traveling. The duty ratio of the valve control time VCTL for opening and closing is determined.

At this time, the virtual vehicle speed ■i is subtracted from the stored vehicle speed MV to obtain the vehicle speed deviation Vd, and the vehicle speed deviation Vd is determined as the predetermined vehicle speed deviation ■
[Determine if the vehicle speed deviation is less than or equal to the predetermined vehicle speed deviation.
is less than a predetermined acceleration aL, the acceleration a is set to zero, so when the vehicle speed deviation Vd is Vd=O, the valve control time VC exactly is VCTL = G-Vd = 0, and When the acceleration a is a=O, the valve control time VCTL is VCTL - G - Vd = G (MV - V), and the valve control time VCTL is only a simple speed difference, which opens and closes the control valve ■1 and the vent valve V2. The duty ratio of the valve control time VCTL is determined. At this point, if the simple speed difference is zero, the valve control time V
CTL becomes zero.

In particular, when the current vehicle speed during constant speed driving control is equal to the memorized vehicle speed MV and the actual acceleration is zero, if the acceleration a becomes an arbitrary value due to the influence of noise, the virtual vehicle speed V1 becomes yr =
Although y+a-Kt appears as a positive or negative vehicle speed deviation depending on the noise characteristics, the influence of the noise can be eliminated by setting a dead zone in the acceleration value as well.

By the way, in the constant speed traveling device of the above embodiment, the memory vehicle speed M
The electronic control means that compares v with the virtual vehicle speed Vi and controls the actuator means in a direction to eliminate the vehicle speed difference is an electronic control circuit CP such as a single-chip microcomputer.
Although the present invention is implemented using a single-chip microcomputer, the present invention is not limited to the single-chip microcomputer described above.

In addition, in the constant speed traveling device of the above embodiment, as a means for calculating the vehicle speed deviation, the stored vehicle speed in which the traveling speed for constant speed traveling is set is compared with the virtual vehicle speed. Since it is practically difficult to detect the current vehicle speed due to the delay in signal processing time, a value calculated by taking into account the delay in signal processing is used. However, when implementing the present invention, as long as the vehicle speed and acceleration at the time of detection are used, the present invention is not restricted to a specific formula. In any case, this is also a virtual vehicle speed since it does not match the actual vehicle speed.

In the above embodiment, the power source for driving the actuator means was set to negative pressure. However, when implementing the present invention, the power source is not limited to the above-mentioned negative pressure, and positive pressure can be used. Can be adapted to fluids. Naturally,
At this time, when the amount of the accumulated power source decreases, the means for supplying it is a pump means depending on the medium.

[Effects of the Invention] As described above, the present invention provides a vehicle speed detection means for detecting the current vehicle speed, a storage means for storing the speed of the traveling vehicle traveling at a constant speed, an actuator means for controlling the opening and closing of the throttle valve, and In a constant speed traveling device comprising an electronic control circuit that controls a duty ratio of the actuator means in a direction to eliminate a vehicle speed deviation based on a stored vehicle speed and a calculated vehicle speed and acceleration, the vehicle speed deviation between the stored vehicle speed and the vehicle speed is The duty ratio control is stopped when the acceleration is below a predetermined value or when the acceleration is below a predetermined value.

Therefore, when the control amount corresponding to the vehicle speed deviation or acceleration is smaller than the dead zone of the control system during constant speed driving, the actuator means that controls the opening and closing of the throttle valve is brought into a stopped state. The number of operations can be reduced. Therefore, it is possible to eliminate energization in the dead zone of control systems such as valves and actuator means, so it is possible not only to reduce the power consumption of valves such as control valves and vent valves, but also to extend their lifespan. can.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a constant speed traveling device according to an embodiment of the present invention, FIGS. 2 to 12 are flowcharts of the constant speed traveling control operation of the electronic control circuit, and FIG. 13 is a constant speed traveling control operation of the electronic control circuit. A flowchart showing another example of travel control operation, FIG. 14 is a control characteristic diagram of vehicle speed deviation used for dividing the valve-on time of the constant speed travel device of the embodiment shown in FIG. 1, and FIG. FIG. 16 is a control output characteristic diagram of the acceleration used for calculating the valve-on time of the constant speed traveling device of the embodiment shown in FIG.
FIG. 17 is a control characteristic diagram of a conventional control valve and vent valve. In the figure, BP... Vacuum pump, S... Throttle valve, AC... Negative pressure actuator, ST... Gas tank, CPU... Electronic control circuit, ■1... Control valve, v2...Vent valve, V3...Release valve. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts. Patent applicant Aisin Seiki Co., Ltd.

Claims (2)

[Claims] (1) A vehicle speed detection means for detecting the current vehicle speed, a storage means for storing the speed of the vehicle traveling at a constant speed, an actuator means for controlling the opening and closing of the throttle valve, and eliminating vehicle speed deviation from the stored vehicle speed, vehicle speed, and acceleration. an electronic device that controls the duty ratio of the actuator means in the direction and stops the duty ratio control when the vehicle speed deviation between the stored vehicle speed and the vehicle speed is less than or equal to a predetermined value or when the absolute value of the acceleration is less than or equal to a predetermined value; A constant speed traveling device comprising a control circuit. (2) The constant speed traveling device according to claim 1, wherein the value of the duty ratio at which the duty ratio control of the actuator means is stopped is set to be greater than or equal to the dead zone of a control valve or a vent valve.