JPH0571409B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a constant speed driving device for an automobile, and more particularly, to a device for shifting an automatic transmission so as to maintain constant speed driving in a desired state on a downhill slope. down·
The present invention relates to a constant speed driving device for an automobile that can suitably perform shift-up control.

(Prior art) In a conventional automatic transmission vehicle equipped with a constant speed traveling device that controls the speed so that the vehicle travels at a constant speed at a set speed, while driving at a constant speed in the overdrive range, sudden changes occur. Engine braking is less effective when going downhill, and the vehicle speed may increase significantly above the set vehicle speed. Therefore, the special public official
In the constant speed traveling device for vehicles disclosed in Publication No. 126142, when a vehicle equipped with an automatic transmission with overdrive is traveling at a constant speed in the overdrive range, the effectiveness of engine braking is poor on a steep downhill slope, and the vehicle speed decreases. If the vehicle speed increases by more than a predetermined value than the set vehicle speed value, the system will shift down from the overdrive range, so if the vehicle is traveling at a constant speed and the vehicle is on a steep downhill slope, the shift will be automatically down. The effectiveness of engine braking has improved, making it possible to suppress increases in vehicle speed.

(Problems to be Solved by the Invention) However, in the constant speed traveling device configured as described above, when the vehicle speed is near a predetermined value greater than the above set value, or when the downhill slope is long,
There is a problem in that downshifts and upshifts occur in succession, resulting in hunting.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a constant speed driving device for an automobile that can prevent hunting during downshifts and upshifts of an automatic transmission even when the automobile is traveling at a constant speed downhill. It is.

(Means for Solving the Problems) As shown in FIG. 1, the constant speed traveling device for a motor vehicle according to the present invention includes a shift switching means b for shifting up and downshifting the gear stage of an automatic transmission a of a motor vehicle. , a fuel supply control means d for controlling the amount of fuel supplied to the engine c, a vehicle speed detection means e for detecting the vehicle speed, and controlling the fuel supply control means to maintain the vehicle speed at a set vehicle speed f. When the vehicle speed detected by the vehicle speed detecting means increases by a predetermined value or more than the set vehicle speed during driving, the shift switching means is operated to downshift after a first set time, and the vehicle speed reaches the set vehicle speed. The present invention is characterized by comprising a control means g for operating the shift switching means to shift up after a second set time when the vehicle speed returns to a speed equal to or less than the predetermined value. Note that it is desirable that the second set time is longer than the first set time.

(Operations and Effects of the Invention) In the constant speed traveling device for a motor vehicle of the present invention configured as described above, when the vehicle speed becomes a predetermined speed or more than the set vehicle speed while traveling at a constant speed, the first
When the automatic transmission is shifted down after the set time and returns to the predetermined speed, the automatic transmission is shifted up after the second set time, so that shift hunting of the automatic transmission can be prevented by the effects of the first and second set times.

(Example) A constant speed traveling device for an automobile according to a preferred embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, the constant speed traveling device has a power supply
The control device 11 is connected via a main switch 14 to a power supply circuit 13 led from 0 via an ignition switch 12. This control device 11 is composed of a microcomputer,
It includes a central processing unit (CPU) that performs various calculations, a fixed storage unit (ROM) that contains control programs shown in the flowchart described later, and a random access memory (RAM) that temporarily stores various data. This control device 11 includes a set switch 1 as a vehicle speed setting means.
6, signals from the coast switch 17 and the resume switch 18, and a signal from the vehicle speed sensor 19 that detects the vehicle speed are input, and the control device 1
1 outputs a signal to a fuel supply device 20 that controls the amount of fuel supplied to the engine and an automatic transmission 21.

The above set switch 16, coast switch 1
7 and a resume switch 18 are connected between the control device 11 and the ground. Among these switches, the set switch 16 is connected when the vehicle speed indicated by the signal from the vehicle speed sensor 7 is, for example, 40 to 100 km/h.
When the vehicle speed is within the range of h, by turning on the switch when the desired vehicle speed is reached, the vehicle speed at that time is set as the set vehicle speed for constant speed driving.
Furthermore, the coast switch 17 is used to decelerate the vehicle while traveling at a constant speed, and the vehicle speed decreases when it is turned on. Further, when the constant speed driving control is canceled due to a reason other than turning off the main switch 14, the resume switch 18 is turned on to return the vehicle to the set vehicle speed before the cancellation. And these switches 1
6, 17, 18 and the signal from the vehicle speed sensor 19, the control device 11 sends the solenoids 23a, 23b, 23c of the actuator 23 of the engine fuel supply control device 22 to maintain the vehicle speed,
A signal is output to decelerate or restore the speed. Further, when traveling at a constant speed, if the vehicle speed increases by a predetermined value or more from the output of the vehicle speed sensor 7 on a downhill slope, the shift down signal Sd is sent to the automatic transmission 21 as described later.
Output.

Next, to explain the configuration of the actuator 23, as shown in FIG.
3 is a negative pressure diaphragm type actuator, and a rubber diaphragm 2 is installed inside the casing 26.
The diaphragm 27 is partitioned into a negative pressure chamber 28 that is airtight to the outside by a negative pressure chamber 28 and an atmospheric chamber 30 that is communicated with the outside by a through hole 29. 31 to the atmospheric pressure and the 30 side, and the casing 26
A solenoid valve 51 for introducing negative pressure that controls the introduction of negative pressure into the negative pressure chamber 28 and first and second solenoid valves 52 and 53 for introducing atmospheric air (the second solenoid valve 53 for introducing atmospheric air is shown in the figure). (not shown). A rod 32 connected to the diaphragm 27 is slidably held by a bearing 33 provided on the casing 26 and protrudes to the outside through the atmospheric chamber 30. is connected to the throttle valve 35 provided in the intake passage of the engine, and is connected to the A direction of the diaphragm 27 (negative pressure chamber 28 side).
When moving to , the throttle valve 35 is operated in the opening direction.

Further, the negative pressure introduction solenoid valve 51 opens a passage 51b, which has one end connected to the negative pressure introduction pipe 36 led from the negative pressure source and the other end communicated with the negative pressure chamber 28, with the valve body 51c. The valve body 51c is pressed and biased by a spring 51d to shut off the passage 51b, and also opens the passage 51b against the spring 51d when the solenoid 23a is energized. will be moved to Similarly, the first atmosphere introduction solenoid valve 52 (the same applies to the second atmosphere introduction solenoid valve 53) has a passage 52b that is open to the atmosphere at one end and communicated with the negative pressure chamber 28 at the other end. The valve element 52c is tension-biased by a spring 52d to open the passage 52, and the solenoid 23
When energization of b is applied, the passage 52b is blocked against the spring 52d. By controlling the energization of the solenoids 23a, 23b, and 23c in these solenoid valves 51, 52, and 53 by signals from the control device 11 shown in FIG. is controlled, and the opening degree of the throttle valve 35 is controlled by displacing the diaphragm 27 in accordance with this negative pressure.

Next, the specific operation of the above embodiment will be explained.

For example, when the vehicle speed is 40 to 100 during normal driving
When the speed is within the range of Km/h, turn on the set switch 16 connected to the control device 11 of the constant speed traveling device.
When operated, the current vehicle speed indicated by the signal from the vehicle speed sensor 19 is set as the set vehicle speed V _S by the control device 11.
From then on, the actual vehicle speed V _A is set by comparing this set vehicle speed with the actual vehicle speed V _A indicated by the signal from the vehicle speed sensor 19.
A signal is output from the control device 11 to the actuator 23 so as to match V _S .

That is, when the actual vehicle speed V _A becomes lower than the set vehicle speed V _S , the control device 11 sends the actuator 23 to the solenoid valves 23a and 23b of the negative pressure introduction solenoid valve 51 and the first atmosphere introduction solenoid valve 52.
An energization signal is output to the negative pressure introduction solenoid valve 51, which opens the first atmosphere introduction solenoid valve 52.
closes. Therefore, negative pressure is introduced into the negative pressure chamber 28 of the actuator 23, and the diaphragm 27
Along with this, the rod 3
2 and the throttle valve 35 via the wire 34.
is operated in the opening direction. As a result, the actual vehicle speed increases and becomes equal to the set vehicle speed. on the other hand,
When the actual vehicle speed V _A is higher than the set vehicle speed V _S , the solenoids 23a and 23b are not energized, so that the negative pressure introduction solenoid valve 51 is closed and the first atmosphere introduction solenoid valve 52 is opened.
Therefore, the negative pressure within the negative pressure chamber 28 is reduced. Therefore, the diaphragm 27 is displaced in the direction opposite to A, and the throttle valve 35 is operated in the closing direction.
As a result, the actual vehicle speed is reduced to match the set vehicle speed. In addition, during such constant speed traveling control, the solenoid 23c of the second atmosphere introduction solenoid valve 53 is always energized and the valve 53 is maintained in a closed state. Furthermore, when the clutch switch 24 or the brake switch 25, which serves as a means for canceling the constant speed running control, is turned on, the energization to the solenoids 23a, 23b, and 23c is all stopped, and the negative pressure introducing solenoid valve 51 is closed. , and the operation of the actuator 23 is completely stopped by opening the first and second atmosphere introduction solenoid valves 52 and 53 and opening the inside of the negative pressure chamber 28 to the atmosphere,
The engine throttle valve 35 is operated by operating the accelerator pedal.

Here, when the vehicle is traveling at a constant speed, it may not be possible to maintain the constant speed traveling state only by adjusting the opening degree of the throttle valve 35 as described above. For example, when traveling down a long downhill slope, the actual vehicle speed V _A will significantly exceed the set vehicle speed V _S if the vehicle remains in fourth gear, which is the gear position during constant speed travel.

Therefore, in the present invention, as shown in FIG. 4, when the actual vehicle speed V _A exceeds the set vehicle speed V _S by a predetermined value ΔV or more, the control device 11 operates to shift from the fourth gear to the fourth gear after Δt _one hour. Shift down to 3rd gear, and due to this downshift, the actual vehicle speed V _A
When becomes smaller than V _S +ΔV, by shifting up from 3rd gear to 4th gear after Δt ₂ hours, constant speed driving is maintained and the above Δt ₁ ,
Hanging is prevented between the fourth and third speeds by the action of Δt ₂ . Note that Δt ₁ = 3 sec, Δt ₂ =
It is desirable to set it to about 15 seconds.

Next, while referring to the flowchart in Figure 5,
The details of the above vehicle speed control will be explained. In addition, in this control, we will proceed with the discussion assuming that V _S +ΔV is V _S again. Also, in the following explanation,
“SF” indicates a shift flag, and when SF=1,
3rd speed is shown, and when SF=0, overdrive (4th speed) is shown.

When constant speed driving starts, the shift flag is
SF is set to 0, and constant speed driving control is performed.
After this, is there a speed deviation, i.e. V _A −V _S ≧
If the determination is NO, it is determined whether the current speed is 4th gear. If this determination is YES, the process returns to the constant speed running control step.
When the above judgment of V _A −V _S ≧0 is YES, SF
If the determination is YES, the process returns to the constant speed running control step.

If the above judgment of V _A −V _S ≧0 is YES and the judgment of SF = 1 is NO, it means that you are driving in 4th gear and have exceeded V _A or V _S for the first time. Sometimes, the timer is started, and after 3 seconds have elapsed, the gear is downshifted from the 4th gear to the 3rd gear, and then the SF is set to "1" and the process returns to the constant speed running control step.

On the other hand, the above judgment of V _A −V _S ≧0 is NO, and SF
If the determination is NO, you are driving in 4th gear, and V _A has become larger than V _S , so you shift down to 3rd gear, and only after that downshift do you start driving in 4th gear.
This means that V _A has become smaller than V _S. At this time, start the timer operation, shift up from 3rd gear to 4th gear after 15 seconds have passed, and
SF is set to 0 and the process returns to the constant speed running control step.

As explained above, according to the present invention, when downshifting and upshifting while driving at a constant speed, these shift changes are performed a predetermined time after satisfying predetermined setting conditions. It is possible to prevent gear change hunting on slopes, etc.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a constant speed traveling device according to the present invention, FIG. 2 is a block diagram showing main parts of a constant speed traveling device according to an embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view showing the configuration of the actuator, FIG. 4 is a time chart illustrating an example of constant speed cruise control of the present invention, and FIG. 5 is a flow chart illustrating an example of constant speed cruise control of the present invention. a... automatic transmission, b... shift switching means, c
...Engine, d...Fuel supply control means, e...
Vehicle speed detection means, g... control means.

Claims (1)

[Scope of Claims] 1. Shift switching means for shifting up and downshifting the gear stage of an automatic transmission of an automobile, fuel supply control means for controlling the amount of fuel supplied to the engine, and vehicle speed detection means for detecting the vehicle speed; The fuel supply control means is controlled to maintain the vehicle speed at a set vehicle speed, and when the vehicle speed detected by the vehicle speed detection means increases by a predetermined value or more than the set vehicle speed when traveling downhill, the first setting is performed. after a period of time, actuate the shift switching means to downshift;
A constant speed traveling device for a motor vehicle, comprising: a control means for operating the shift switching means to shift up after a second set time when the vehicle speed returns to a speed equal to or less than the predetermined value added to the set vehicle speed. 2. The constant speed traveling device for a motor vehicle according to claim 1, wherein the second set time is longer than the first set time.