JPS6053432A - Constant speed travel system for car - Google Patents

Abstract

PURPOSE:To reduce overshoot against the target speed considerably by detecting the speed variation immediately before exchange to automatic constant speed travel previously thereby operating the control amount of throttle valve. CONSTITUTION:Under travelling, the output from a car speed sensor 1 is taken into the speed control section 7 to store the car speed data U1, U2 within the setting time obtained in the first and second time decision steps. Then they are compared to operate the output signals from each output terminal A, B and the duty of said signals. Upon turning on of set switch 3 to transfer to automatic constant speed travel, the drive section 8 is controlled in accordance to the newest output signal from said output terminals A, B. If both output signals are L, for example, motor 11 for driving an atmosphere releasing solenoid valve 10 and negative pressure pump 12 is turned off to close the throttle valve 13 and the perform deceleration control.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a constant speed traveling device for a vehicle.

Conventional constant speed running devices for vehicles automatically run at a constant speed at a given vehicle speed in a manual running state (even if the set switch is turned on, the current vehicle speed data is detected for the first time at that point, and the vehicle speed data is The throttle valve is controlled by calculating the control amount of the throttle valve based on the above-mentioned current vehicle speed data.Therefore, there is a long delay from when the set switch is turned on until the throttle valve is automatically controlled based on the current vehicle speed data. An overshoot phenomenon occurs in which the actual vehicle speed deviates significantly from the target vehicle speed set by the driver.As a result, the transition from the manual driving state to the automatic constant speed driving state cannot be performed smoothly. The drawback was that it took a long time to drive at a constant speed.

The present invention was invented in view of the above problems, and its purpose is to detect in advance a change in vehicle speed before switching to automatic constant speed driving, and to calculate the control amount of the throttle valve to switch to automatic constant speed driving. To provide a constant speed traveling device for a vehicle that can significantly reduce an overshoot phenomenon with respect to a target set vehicle speed at the time of transition and can smoothly transition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the constant speed traveling device for a vehicle according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a vehicle speed unit that detects the vehicle speed and outputs a pulse signal corresponding to the detected vehicle speed as vehicle speed data. 2 is a main switch that supplies power to a speed control section 7, which will be described later. 3 is a speed increasing switch that sets the vehicle speed in manual running state to the set vehicle speed when running at constant speed when desired, 4 is a speed increase switch that automatically increases speed from manual running state, and 5 is a predetermined vehicle speed. This is a vehicle speed return switch that returns to the automatic constant speed running state at the predetermined vehicle speed after the automatic constant speed running state is once switched to manual running using a release switch 6, which will be described later.

Reference numeral 6 denotes a release switch (for switching the vehicle from an automatic constant-speed running state at a predetermined set vehicle speed to manual running when the set switch 3 is turned ON), and is interlocked with, for example, a brake or a clutch.

Reference numeral 7 denotes a speed control section, which inputs and calculates each signal from the vehicle speed control section 1, main switch 2, set switch 3, speed increase switch 4, vehicle speed return switch 5, and release switch 6 to generate a vehicle speed control signal. It has a function to output. In addition, the speed control unit 7 repeatedly inputs the first vehicle speed data and the almost immediately subsequent vehicle speed data from the vehicle speed sensor 1 in chronological order, constantly compares both vehicle speed data, and also outputs a switch signal from the set switch 3. At the time when the switch signal is input, the controller has a function of outputting a vehicle speed control signal corresponding to the difference between the two vehicle speed data immediately before the switch signal is input. The speed control section 7 is composed of, for example, a microcomputer.

8 is a drive section that outputs a drive signal based on the vehicle speed control signal from the speed control section I, and includes three NPN transistors T, , T2. Ts and four resistors R1 to R,
Consists of. The first transistor T1 has its base connected to the positive terminal of the DC power supply V, and its emitter connected to the second transistor T1.
It is connected to the 2nd collector. Second transistor T2
The base is connected to the output terminal B of the speed control unit I through the resistor R2, the emitter is grounded, and the collector is connected to the base of the third transistor T3 and is also grounded through the resistor R3.

Connected to the positive terminal of the power supply +V and the first
Connected to the collector of transistor T.

9 is a negative pressure actuator consisting of a diaphragm type actuating mechanism, etc., and the atmospheric pressure actuator 9 is connected to a throttle valve 13 via a solenoid valve 1o, and the valve opening degree flj
ll side 1 is on. In this case, when the solenoid valve 10 is turned ON, the valve closes.

The capacity pressure pump 12 sucks the air in the diaphragm of the negative pressure actuator 9 to create a negative pressure when the motor 11 is turned on.

Next, the operation of the above structure will be explained based on FIGS. 2 to 4.

When the main switch 2 is turned on, the speed control section 7 starts operating NJJ.
Start. A case where the speed control section 7 is configured by a microcomputer will be explained based on the f control flowchart in FIG. First, step 101 is to obtain first vehicle speed data.
is input from the vehicle speed sensor 1].The pulse signal input from the vehicle speed sensor 1 is counted as the first vehicle speed data U. Next, a first time count step 102 determines whether the time TI after the first vehicle speed data count step 101 starts counting the first vehicle speed data U1 has reached a preset time TI, and if YES. Then, the process proceeds to vehicle speed data storage step 103, and if NO LIJ, the first vehicle speed data is stored in step 1.
The process returns to 01 and continues counting the next pulse signal input from the vehicle speed sensor 1. The vehicle speed data storage step 103 stores the first vehicle speed data U1 counted in the vehicle speed data count step 101 within the set time TI. Next, the second vehicle speed data counting step 104 is the first vehicle speed data counting step 101.
Similarly, the first pulse signal inputted from the vehicle speed sensor 1 thereafter is counted as the second vehicle speed data U2. The second time scale step 105 is the time TI after the start of the second vehicle speed data U2, similar to the first time scale step 102.
2 has reached the set time TI. If YES, proceed to vehicle speed data comparison/calculation step 106; if NO, return to second vehicle speed data count step 104, and calculate the next value input from vehicle speed sensor 1. Caranthra continuation of pulse signal 1-. Vehicle speed data comparison/calculation step 1
06 is both vehicle speed data u within the same set time TI
, , u2'v are compared, and based on the comparison data, the output signal from each output terminal A, B and the duty of the output signal are calculated and determined. Next, in the set switch signal determination step 107, if the set switch 3 is ON, the process proceeds to an output step 108, and if it is OFF, the process returns to the first vehicle speed data count step 101. Therefore, during manual driving, the set switch 3 is OFF, and the vehicle speed data U, .
By counting U2, the calculation of the output signal and the duty of the output signal is repeated. Further, when the set switch 3 is turned on from the manual running state to shift to automatic constant speed running, the end terminals A and 13 are connected to the steps 101 to 10 described above.
6 will be outputted at output step 108 corresponding to control modes a through d in FIG. For example, in control mode a, a low level (L level) signal is output from each output terminal A, B, and the solenoid valve 10 and motor 11 are turned off. Therefore, since the negative pressure state of the negative pressure actuator 9 is alleviated, the vehicle speed is reduced by closing the throttle valve 13.

Thereafter, the process proceeds to steady constant speed driving step 109, where driving control similar to that of a conventional constant speed driving system is performed. Also, when the release switch 6 is turned ONt and a switch signal is input,
The program proceeds to release switch actuation step 110 to return to manual running, and returns to first vehicle speed data count step 101 to prepare for shifting to automatic constant speed running again.

A specific example of vehicle speed control will be explained based on a time chart in FIG. 4 in which the horizontal axis is time T seconds and the vertical axis is vehicle speed ukm//H.

Now, when the actual vehicle speed u1 is in a deceleration state during manual driving, an arbitrary time T. When the set switch I LON t and the set vehicle speed u (, ) are used to shift to automatic constant speed driving, the speed control unit 7 outputs the output terminal A in control mode C based on the actual vehicle speed u in the deceleration state during manual driving. An output signal of H level is output from output terminal B, and an output signal of L level is output from output terminal B. The output duty at this time is determined corresponding to the actual vehicle speed u1 in the deceleration state.

Thus, the first and third transistors TL+T3 are turned on, the second transistor T2 is turned on, and the solenoid valve 1o and the motor 11 are turned on. '4-, actuator 9
opens the throttle valve 13. Therefore,
At the actual vehicle speed U, the deceleration gradient during manual driving eases, and the cloud suddenly turns into a speed increase gradient. Therefore, the vehicle speed and set vehicle speed U at which the actual vehicle speed U changes to the above acceleration gradient. overshoot value S with
will be significantly reduced.

Since the constant speed traveling device for a vehicle according to the present invention has the above-described configuration and operation, it has the following effects.

By detecting in advance the change in vehicle speed immediately before switching to automatic constant speed driving in the speed control section and calculating the throttle valve control amount, the overshoot phenomenon with respect to the target vehicle speed during automatic constant speed driving is greatly reduced. Reduce and
We were able to provide a constant speed vehicle travel device that allows for smooth transition.

[Brief explanation of the drawing]

1 to 4 show an embodiment of a constant speed traveling device for a vehicle according to the present invention, FIG. 1 is an electric circuit diagram, and FIG.
Fig. 3 is an explanatory diagram of the operation of the configuration shown in Fig. 3.
@1 Flowchart, FIG. 4 is a time chart of the configuration of FIG. 1. 1...Vehicle speed setting/su, 3...Set switch, 7...
・Speed W tllJ GogB , 13... Throttle valve. 31El Figure 4 IQ/l-

Claims (1)

[Claims] A vehicle speed sensor that detects the traveling speed of the vehicle and outputs it as vehicle speed data, a set switch that sets the vehicle to run at a constant speed in a manual running state at a desired time, and the first vehicle speed data from the vehicle speed sensor and the vehicle speed almost immediately thereafter. The data are repeatedly input in chronological order and the vehicle speed data of both are constantly compared, and at the time of inputting the switch signal of the set switch, the data is inputted according to the difference between the vehicle speed data of the two above immediately before the input of the thigh switch signal. A constant speed traveling device for a vehicle, characterized in that it includes a speed control section that controls the opening and closing of a throttle valve.