JPH0227169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant-speed traveling system for a motor vehicle, which advances the throttle angle of an internal combustion engine so that the vehicle travels at a set speed.

In the prior art, the advance time is determined during constant speed driving at the set vehicle speed, when the vehicle speed increases to the original set speed after canceling the set vehicle speed, and during override when the actual vehicle speed is higher than the set vehicle speed. In either case, the advance time is set constant. If this advance time is set to a small value, undershooting is likely to occur when the set vehicle speed is reached during override. Also, overshoot tends to occur when resuming. Furthermore, if the advance angle time is set to a large value, a hunting phenomenon is likely to occur during constant speed driving. Therefore, in the prior art, it is difficult for the actual vehicle speed to stably reach the set vehicle speed quickly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a constant speed traveling device for an automobile that allows the actual vehicle speed to stably and quickly reach the set vehicle speed.

The present invention provides a constant-speed running system for a vehicle in which the throttle angle of an internal combustion engine is controlled in advance so that the vehicle travels at a set vehicle speed, and in which the advance angle time is set to a first predetermined time while the vehicle is traveling at the set vehicle speed. , when the actual vehicle speed decreases below a predetermined vehicle speed that is smaller than the set vehicle speed, the advance angle time is increased to a second predetermined time that is larger than the first predetermined time until the actual vehicle speed reaches the set vehicle speed or very close to the set vehicle speed. If the actual vehicle speed exceeds a predetermined vehicle speed that is greater than the set vehicle speed, the advance time is changed to a third time that is greater than the second predetermined time until the actual vehicle speed reaches the set vehicle speed or very close to it. This is a constant speed traveling device for an automobile, characterized in that the switching is performed at a predetermined time.

FIG. 1 is a block diagram of one embodiment of the present invention. Electrical signals from a means 1 for setting a set vehicle speed and an actual vehicle speed detecting means 2 for detecting an actual traveling speed are given to a processing device 3 including a microcomputer and the like. The processing device 3 drives the actuator 4 . The throttle valve 5 provided in connection with the internal combustion engine that drives the body of the automobile is
It is connected to the actuator 4 via a link mechanism 6. This link mechanism 6 is connected to an accelerator pedal 7 operated by a driver. Actuator 4 includes an electromagnetic solenoid that drives link mechanism 6 . This electromagnetic solenoid is energized by a pulse having the waveform shown in FIG. The processing device 3 derives a pulse consisting of a pulse duration, ie, an excitation period W1 of the electromagnetic solenoid, and a pulse rest period, ie, a demagnetization period W2 of the electromagnetic solenoid. The processing device 3 changes the duty (=W1/W) of this pulse, thereby changing the pulling force of the link mechanism 6 related to the throttle valve 5 by the actuator 4.

Therefore, depending on the duty of the pulse applied from the processing device 3 to the actuator 4, the opening end area, that is, the degree of opening of the throttle valve 5 changes as shown in FIG. As the duty increases, the opening degree of the throttle valve increases.

Referring to FIG. 4, processing operations according to the execution of the program by the processing device 3 will be described. Vehicle speed setting means 1
The vehicle speed set by V0 is V0, and the predetermined vehicle speeds above and below the set vehicle speed V0 are V1a,
Let V1b be V1b, and predetermined upper and lower vehicle speeds greater than these vehicle speeds V1a and V1b are V2a and V2b.

In response to the output from the actual vehicle speed detection means 2, the processing device 3 compares the actual vehicle speed, the set vehicle speed V0, the vehicle speeds V1a, V1b; V2a, V2b, and determines the magnitude relationship and difference. Vehicle speed V1a, V1
b; V2a and V2b are values for setting the advance angle time by comparison with the actual vehicle speed.

At the time of resume before time t2, the solid line l
The actual vehicle speed indicated by 1 is less than or equal to the vehicle speed V1b. At this time, the advance angle time with respect to the virtual vehicle speed l2 shown by the broken line is:
As shown in FIG. 42, it is T2. The virtual vehicle speed l2 is a virtual vehicle speed that will be reached after an advance time based on the current actual vehicle speed and acceleration. The duty is determined from the difference between this virtual vehicle speed and the set vehicle speed. The control speed width (V3a-V3b) is the range in which the duty falls within 0 to 100%, and when the virtual vehicle speed exceeds the control speed width, the duty remains at 0%, and when the virtual vehicle speed falls below the control speed width, the duty remains at 0%. Duty remains at 100%.

At time t1, the actual vehicle speed becomes the predetermined vehicle speed V.
Even if it reaches 1b, the advance time immediately changes from T2 to T1.
(However, T1<T2), but the advance angle time is changed to T1 after an appropriate delay time Δt1 in consideration of the time required for the actual vehicle speed to settle to the set vehicle speed. This allows the actual vehicle speed to stably and quickly reach the set vehicle speed V0 without overshooting.

Between times t2 and t3, the virtual vehicle speed matches the set vehicle speed V0, and a constant duty corresponding to this virtual vehicle speed is maintained.

At time t3, when the driver depresses the accelerator pedal to start override and the virtual vehicle speed increases beyond the set vehicle speed V0, the duty decreases.

When the actual vehicle speed exceeds vehicle speed V3a at time t4, the advance time changes from T1 to T3 (however, T1<T2
<T3), so the virtual vehicle speed becomes vehicle speed V3a
exceeds the control speed range (V3a-V3b). Therefore, the duty becomes 0%.

At time t5, the virtual vehicle speed becomes equal to the control speed width (V
3a-V3b), and then when the actual vehicle speed reaches vehicle speed V1a at time t6, the delay time Δt6
After that, the advance time changes from T3 to T1. Therefore, the actual vehicle speed stably and quickly reaches the set vehicle speed V0 without causing any undershoot.

At time t7, when the actual vehicle speed approaches the set vehicle speed V0 and the virtual vehicle speed reaches the set vehicle speed V0, the duty is maintained at a predetermined value.

At time t8, the virtual vehicle speed becomes lower than the set vehicle speed V0, thereby increasing the duty.

When the actual vehicle speed becomes less than vehicle speed V2b at time t9, the advance time is changed from T1 to T2, so that the virtual vehicle speed becomes less than the control speed range (V3a-V3b) and the duty becomes 100%.

At time t10, the virtual vehicle speed reaches the control speed width (V3a
-V3b), the duty is decreasing. In this way, the change in duty shown in FIG. 4 is represented by a waveform that is an inversion of the virtual vehicle speed shown by curve 12 in FIG. 4.

The reason for making the advance time T3 longer than T2 is as follows. In other words, when resuming, as the actual vehicle speed approaches the set vehicle speed, the throttle opening degree is reduced to the opening degree corresponding to the set vehicle speed (control in the closing direction), whereas during override, the actual vehicle speed approaches the set vehicle speed. This control increases the throttle opening degree to the opening degree corresponding to the set vehicle speed as the vehicle speed approaches (control in the opening direction). On the other hand, there is a difference in response delay when controlling the throttle opening in the closing direction and when controlling it in the closing direction due to the action of a spring etc. provided on the throttle valve, and the response delay in the latter case is larger. Therefore, by making the lead angle time T3 during override larger than the lead angle time T2 during resume, it is possible to perform optimal lead angle control.

Therefore, when the vehicle is running at a constant speed, the advance time T1 is small, and the throttle valve 5 is controlled with small changes. At the time of override, a large advance time T3 is obtained, and the actual vehicle speed does not become smaller than the set vehicle speed V0 and undershoot occurs, and the set vehicle speed can be stably and quickly reached. Further, when resuming, the vehicle speed is being increased to reach the set vehicle speed, the advance angle time T2 is selected between T1 and T3. As a result, when the actual vehicle speed reaches the set vehicle speed, the actual vehicle speed can stably and quickly reach the set vehicle speed V0 without overshooting the set vehicle speed V0.

As described above, according to the present invention, when the actual vehicle speed exceeds a predetermined vehicle speed that is higher than the set vehicle speed, or when the actual vehicle speed decreases below a predetermined vehicle speed that is lower than the set vehicle speed, the actual vehicle speed changes to the set vehicle speed. Since the advance angle time is made larger than the advance angle time while driving at the set vehicle speed until the vehicle speed reaches or close to the set speed, the actual vehicle speed becomes lower than the set vehicle speed and does not cause undershoot and can be smoothly and stably maintained. And it becomes possible to reach the destination quickly.

Furthermore, according to the present invention, not only the vehicle speed difference but also the direction of change in the actual vehicle speed, such as whether the actual vehicle speed is increasing or decreasing toward the set vehicle speed, is detected, and the advance time is divided into three stages. Since the switching is made, optimum advance angle control can be performed regardless of whether the timing is resumed or overridden.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure shows the waveform of a pulse from the processing device 3 for driving the electromagnetic solenoid included in the actuator 4, FIG. 3 is a graph showing the relationship between the pulse and the opening cross-sectional area of the throttle valve 5, and FIG. FIG. 3 is a waveform diagram for explaining the operation of the embodiment shown in the first figure. 1... Set vehicle speed setting means, 2... Actual vehicle speed detection means, 3... Processing device, 4... Actuator,
5...Throttle valve, 6...Link mechanism, 7...
Accelerator pedal, T1, T2, T3...Advance time.

Claims (1)

[Claims] 1. In a constant speed running system for a vehicle that advances the throttle angle of an internal combustion engine so that the vehicle travels at a set speed, the advance time is set to a first predetermined time while the vehicle is running at the set speed, and the actual vehicle speed is is lower than a predetermined vehicle speed that is smaller than the set vehicle speed, the advance time is switched to a second predetermined time that is larger than the first predetermined time until the actual vehicle speed reaches the set vehicle speed or very close to the set vehicle speed. If the actual vehicle speed exceeds a predetermined vehicle speed that is greater than the set vehicle speed, the advance time is increased to a third predetermined time that is greater than the second predetermined time until the actual vehicle speed reaches the set vehicle speed or very close to it. 1. A constant speed traveling device for an automobile, characterized in that the constant speed traveling device is configured to switch to.