JPH0571411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a constant speed running device for an automobile, and more particularly, to a system for automatically shifting an automatic transmission to maintain a desired constant speed running on a downhill slope.・
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 traveling at a constant speed due to overdrive, it is difficult to Engine braking may not be as effective on hills, and the vehicle speed may increase significantly above the set vehicle speed. Therefore, JP-A-59-
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 even when driving at a constant speed and going down a steep slope, the system will automatically downshift. , 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 or equal to the set vehicle speed value, or when the downhill slope is long, , a problem arises in that a sit-down and a shift-up occur consecutively, 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 automatic transmission from shifting down or upshifting even when the automobile is traveling at a constant speed downhill. It is something.

(Means for Solving the Problem) As shown in FIG. 1, the constant speed traveling device for a motor vehicle of the present invention has a shift switching means b for shifting up and downshifting the gear stage of an automatic transmission a of a motor vehicle.
, fuel supply control means d for controlling the amount of fuel supplied to the engine c, and vehicle speed detection means e for detecting the vehicle speed.
and controlling the fuel supply control means to maintain the vehicle speed at the set vehicle speed f, 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, After a first set time, the shift switching means is operated to downshift, and when the vehicle speed returns to a vehicle speed equal to or less than the set vehicle speed plus the predetermined value, the shift switching means is operated after a second set time. a control means g for shifting up, and a vehicle speed for calculating the vehicle speed change rate immediately before the time when the vehicle speed increases by a predetermined value or more from the set vehicle speed and the time when the vehicle speed returns to a vehicle speed equal to or less than the predetermined value added to the set vehicle speed, respectively. a rate-of-change calculation means h, and the first and second
The apparatus is characterized by comprising a time setting means i for setting a set time. Note that, depending on the magnitude of the vehicle speed change rate, the time setting means:
It is desirable that the first set time is set short and the second set time is set long.

(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 shut down after the set time and returns to the predetermined speed, it is shifted up after the second set time, so that shift hunting of the automatic transmission can be prevented by the first and second installation times and actions. Further, in the present invention, when the rate of change in vehicle speed is large, that is, when the vehicle is traveling on a steep slope, the first set time is shortened and the second set time is lengthened, so that the vehicle speed is controlled. The amount of overshoot can be kept small.

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

(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, a signal is output to a heat supply device 20 and an automatic transmission 21 that control the amount of fuel supplied to the engine.

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. In addition, the Ridium Switch 18
When the constant speed driving control is canceled due to a reason other than the OFF operation of the main switch 14, turning it ON returns the vehicle to the set vehicle speed before the cancellation. Based on the operation of these switches 16, 17, and 18 and the signal from the vehicle speed sensor 19, the control device 11 sends the solenoids 23a, 23b, and 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. Additionally, when traveling at a constant speed and on a downhill slope, if the vehicle speed increases by a predetermined value or more from the set vehicle speed based on the output of the vehicle speed sensor 7, a downshift signal is sent to the automatic transmission 21 as described later.
Output SD.

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 toward the atmosphere 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 (the negative pressure chamber 28
When moving to the side), 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 body 52c is tension-biased by a spring 52d to open the passage 52b, and the solenoid 23
When energization of b is applied, the passage 52b is blocked against the spring 52d. The solenoids 23a, 23b, 23c of these solenoid valves 51, 52, 53 are energized and controlled 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, the car side 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 established 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 the .

That is, when the actual vehicle speed V _A becomes lower than the set vehicle speed V _S , an energization signal is output from the control device 11 to the solenoids 23a and 23b of the negative pressure introduction solenoid valve 51 and the first atmosphere introduction solenoid valve 52 in the actuator 23. , the negative pressure introduction solenoid valve 51 opens, and 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 is displaced in the A direction, and along with this, the rod 32
The slot valve 35 is operated in the opening direction via the wire 34. This increases the actual vehicle speed,
It will match the set vehicle speed. On the other hand, the actual vehicle speed
When 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, so that the negative pressure The negative pressure within chamber 28 is reduced. Therefore,
The diaphragm 27 is displaced in the opposite direction A, and the throttle valve 35 is operated in the closing direction, thereby reducing the actual vehicle speed to match the set vehicle speed. In addition, during such constant speed driving control,
Solenoid 2 of the second atmosphere introduction solenoid valve 53
3c is always energized to keep the valve 53 closed. Furthermore, when the crank switch 24 or the brake switch 25, which serves as a means for canceling the constant speed running control, is turned on, each of the solenoids 23
The power supply to a, 23b, 23c is all stopped,
The negative pressure introduction solenoid valve 51 is closed, and the first
The second atmosphere introduction solenoid valves 52 and 53 are opened to release the inside of the negative pressure chamber 28 to the atmosphere, thereby completely stopping the operation of the actuator 23, and the engine throttle valve 35 is opened by operating the accelerator pedal. It will be activated.

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 the fourth gear, which is the gear 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 △V or more, the controller 11 operates to shift the speed to 4th gear after △t _one hour. A downshift is performed from 3rd gear to 3rd gear, and due to this downshift, the actual vehicle speed V _A
When becomes smaller than V _S +△V, by shifting up from 3rd gear to 4th gear after △t ₂ hours, constant speed driving is maintained and the above △t ₁ ,
The action of Δt ₂ prevents hunting between the fourth and third speeds. Furthermore, in the present invention, in the control circuit 11, _{the vehicle} speed _change rate |dV _{A /} dt| is calculated, and the first setting time △t ₁ is set short and the second setting time △t ₂ is set long according to the magnitude of this vehicle speed change rate, thereby reducing control overshoot. The amount is reduced. Note that when the above |dV _A /dt| is 3 Km/lsec, 4 Km/lsec, and 5 Km/lsec, it is desirable to set Δt ₁ to about 3 sec, 4 sec, and 5 sec, respectively.

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, the discussion will be continued 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 is YES if V _A −V _S ≧0 and NO if SF=1, it means that you are driving in 4th gear and have exceeded V _A or V _S for the first time. Sometimes, first calculate the vehicle speed change rate, then set △t ₁ based on this change rate, start the timer operation, and shift from 4th gear to 3rd gear after this set △t ₁ second has elapsed. Down and SF “1”
Then, the process returns to the constant speed traveling 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, calculate the vehicle speed change rate, then set △t ₂ based on this change, start the timer operation, and set △
After ₂ seconds have elapsed, the gear is shifted up from 3rd gear to 4th gear, SF is set to 0, and the process returns to the above-mentioned constant speed driving control step.

As explained above, according to the present invention, when downshifting or upshifting while driving at a constant speed, these shift changes are performed after a predetermined set condition is satisfied and after a set time based on the vehicle speed change rate. Therefore, it is possible to prevent gear change hunting on long downhill slopes, etc., and to suppress the amount of control overshoot to a small value.

[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, h...vehicle speed change rate calculation means, i...time setting 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;
control means for operating the shift switching means to shift up after a second set time when the vehicle speed returns to a vehicle speed equal to or less than the set vehicle speed plus the predetermined value; a vehicle speed change rate calculation means for calculating the vehicle speed change rate immediately before the time when the vehicle speed increases and the time when the vehicle speed returns to below the set vehicle speed plus the predetermined value; and a vehicle speed change rate calculated by the vehicle speed change rate calculation means. and time setting means for setting the first and second set times accordingly. 2. The automobile according to claim 1, wherein the time setting means sets the first setting time short and the second setting time long, depending on the magnitude of the vehicle speed change rate. Constant speed running device.