JPS6299220A - Constant speed running device for automobile - Google Patents

Abstract

PURPOSE:To promote the convergence of the speed of a vehicle provided with an automatic speed change gear with an overdrive, in a constant speed running device, by providing such an arrangement that a set vehicle speed at which the vehicle is shifted up from its shift-down during the vehicle running on, for example, a descending slope, is temporarily set to a value which is increased by a predetermined value. CONSTITUTION:When an actual vehicle speed VA exceeds a set vehicle speed VS which is set by turning on a set switch 16, by a predetermined value DELTA.V during the vehicle running on a long descending slope, a control device 11 delivers a signal to an automatic speed change gear 21 so that a vehicle is shifted down from the fourth speed stage to the third speed stage. Further, when the vehicle speed VA is less than the set value VS+DELTAV due to the shift-down, the vehicle is shifted up from the third speed stage to the fourth speed stage and a set vehicle speed for constant speed running of the vehicle, is set temporarily to a new set vehicle speed VS1 which is obtained by adding a value which is less than DELTAV to the set vehicle speed VS by turning on the set switch 16, and therefore, the converging time of the vehicle speed is shortened. With this arrangement, it is possible to promote the convergence of the vehicle speed to the set vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a constant speed traveling device for an automobile, and more particularly, to a method for shifting an automatic transmission to maintain constant speed traveling in a desired state on a downhill slope. The present invention relates to a constant speed traveling device for an automobile that can suitably perform down/upshift 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, it is difficult to Engine braking is not as effective on hills, and the vehicle speed may increase considerably above the set vehicle speed. Therefore, in the constant speed traveling device for vehicles disclosed in Japanese Patent Application Laid-Open No. 59-126142, when a vehicle equipped with an automatic transmission with overdrive is running at a constant speed in the overdrive range, the engine If the brakes are not effective and the vehicle speed increases by more than a predetermined value than the set vehicle speed value, it will shift down from the overdrive range, so even if you are driving at a constant speed and approach a steep downhill slope, the system will automatically shift down. This allows the engine to downshift to improve the effectiveness of engine braking and suppress vehicle speed increases.

(Problems to be Solved by the Invention) However, in the constant speed traveling device configured as described above, at the time of upshifting after downshifting,
When constant speed driving control is performed, there is a problem in that the actual vehicle speed converges to the set vehicle speed slowly due to the influence of the predetermined value.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a constant speed driving device for a motor vehicle that quickly converges the vehicle speed to the set vehicle speed after the above-mentioned upshift.

(Means for Solving the Problems) The constant speed traveling device for a motor vehicle of the present invention has a shift switching means for upshifting and downshifting the gear stage of the automatic transmission a of the motor vehicle. a fuel supply control means d that controls the vehicle speed; a vehicle speed detection means e that detects the vehicle speed; and a vehicle speed detection means e that controls the fuel supply means to maintain the vehicle speed at a set vehicle speed f, and when traveling downhill, the vehicle speed detection means detects the vehicle speed. When the vehicle speed increased by a predetermined value or more than the set vehicle speed, 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 is performed. The present invention is characterized in that it includes a control means g that operates the switching means to shift up and temporarily sets the set vehicle speed to a value obtained by adding a value equal to or less than the predetermined value to the set vehicle speed.

(Operations and Effects of the Invention) In the constant speed traveling device for a motor vehicle of the present invention configured as described above, during constant speed driving, when the vehicle speed becomes a predetermined speed or more than the set vehicle speed on a downhill slope, the downshift is performed. When the speed returns to the predetermined speed range, the vehicle is shifted up and the set speed for constant speed driving is temporarily increased slightly, so that the vehicle speed can be quickly collected and stabilized at an early stage.

(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 includes a control device 11 connected via a main switch 14 to a power supply circuit 13 led from a power source 10 via an ignition switch 12. This control device 11 is composed of a microcomputer, and includes a central processing unit (CPU) that performs various calculations, a fixed storage unit (ROM) that contains control programs shown in the flowcharts described later, and a random storage unit that temporarily stores various data. Access memory (RAM
). Signals from a set switch 16, coast switch 17, and resume switch 18 as vehicle speed setting means, and a signal from a vehicle speed sensor 19 that detects vehicle speed are input to this control device 11. , a signal is output to a fuel supply device 20 and an automatic transmission 21 that control the amount of fuel supplied to the engine.

The set switch 16, the coast switch 17, and the 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, When the vehicle speed is within the range of 40 to 1100 k/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. Further, 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. Furthermore, when the constant speed running control is canceled due to a reason other than the OFF operation of the main switch 14, turning the resume switch 18 ON returns the vehicle to the set vehicle speed before the cancellation. Then, the operation of these switches 16, 17, and 18 and the vehicle speed sensor 1
Based on the signal from 9, the control device 11 outputs a signal to the solenoids 23a, 23b, and 23c of the actuator 23 of the engine fuel supply control device 22 to maintain, decelerate, or restore the vehicle speed. It has become. Further, when traveling at a constant speed, when the vehicle speed increases by a predetermined value or more from the output of the vehicle speed sensor 7 on a downhill slope, a shift down signal Sd is output to the automatic transmission 21 as described later.

Next, the structure of the actuator 23 will be explained. As shown in FIG. 3, the actuator 23 is a negative pressure diaphragm type actuator, and is airtight from the outside by a rubber diaphragm 27 inside the casing 26. The negative pressure chamber 28 is divided into a negative pressure chamber 28 and an atmospheric chamber 30 communicated with the outside through a through hole 29, and the diaphragm 27 is biased toward the atmospheric chamber 30 by a spring 31 disposed within the negative pressure chamber 28. At the same time, a negative pressure introduction solenoid valve 51 for controlling the introduction of negative pressure into the negative pressure chamber 28 and first and second atmosphere introduction solenoid valves 52 and 53 (second atmosphere introduction solenoid valves) are installed on the end face of the casing 26. The configuration includes a valve 53 (not shown). A rod 32 connected to the diaphragm 27 is slidably held by a bearing 33 provided on the casing 26 and protrudes outward through the atmospheric chamber 30. The throttle valve 35 is connected to a throttle valve 35 provided in an intake passage of the engine, and the throttle valve 35 is operated in the opening direction when the diaphragm 27 moves in the A direction (towards the negative pressure chamber 28).

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. 52C is configured to open and close the passage, and the valve body 52C is connected to the passage 52 by a spring 52d.
The solenoid 23b is tension-biased to open the passage 52b, and blocks the passage 52b against the spring 52d when the solenoid 23b is energized. The solenoids 23a, 23b, and 23C in these solenoid valves 51, 52, and 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.

During normal driving, the vehicle speed is, for example, 40 to 1100 km/h.
When the set switch 16 connected to the control device 11 of the constant speed traveling device is turned on when the vehicle speed is within the range of h, the current vehicle speed indicated by the signal from the vehicle speed sensor 19 or the set vehicle speed.
, is set in the RAM of the control device 11, and from then on, this set vehicle speed is compared with the actual vehicle speed indicated by the signal from the vehicle speed sensor 19, and the actual vehicle speed is matched to the set vehicle speed. A signal is output from the control device 11 to the actuator 23 to cause the actuator to do so.

In other words. When the actual vehicle speed 5 becomes lower than the set vehicle speed 5, the control device 11 controls the actuator 23 to operate the negative pressure introduction solenoid valve 51 and the first atmosphere introduction solenoid valve 52.
An energizing signal is output to the solenoids 23a and 23b,
The negative pressure introduction solenoid valve 51 opens, and the first atmosphere introduction solenoid valve 52 closes. Therefore, actuator 2
Negative pressure is introduced into the negative pressure chamber 28 of No. 3, and the diaphragm 27 is displaced in the A direction, and in conjunction with this, the throttle valve 35 is operated in the opening direction via the rod 32 and wire 34. As a result, the actual vehicle speed increases and becomes equal to the set vehicle speed. On the other hand, the actual vehicle speed is the set vehicle speed.
, the solenoid valve 51 for introducing negative pressure closes and the first solenoid valve 52 for introducing atmospheric air opens because the solenoid valves 23a and 23b are not energized, so that the negative pressure in the negative pressure chamber 28 is lowered.

Therefore, the diaphragm 27 is displaced in the direction opposite to A, and the throttle valve 35 is operated in the closing direction, thereby reducing the actual vehicle speed to match the set vehicle speed.
During such constant speed running control, the solenoid 23C of the second atmosphere introduction solenoid valve 53 is constantly energized and the valve 53 is kept closed. Further, 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.
The operation of the actuator 23 is completely stopped by closing the negative pressure introduction solenoid valve 51 and opening the first and second atmosphere introduction solenoid valves 52 and 53 to open the inside of the negative pressure chamber 28 to the atmosphere. engine throttle valve 35
is activated by changing 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 will significantly exceed the set vehicle speed if the vehicle remains in 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 4 exceeds the set vehicle speed Vs by a predetermined value Δ■ or more, the controller 11 shifts from the 4th gear to the 3rd gear. When the actual vehicle speed becomes smaller than ■, +Δ■ due to this downshift, the vehicle shifts from 3rd gear to 4th gear and temporarily changes the set vehicle speed for constant speed driving. , the normal set vehicle speed■5,
Newly set vehicle speed Vs, which is the value obtained by adding a value smaller than the above Δ■
This is set to +, thereby shortening the vehicle speed convergence time.

Next, details of the vehicle speed control will be explained with reference to the flowchart shown in FIG. In the following description, "SF" indicates a shift flag; when 5F=1, it indicates third speed, and when 5F=0, it indicates overdrive (fourth speed).

When constant speed driving is started, shift flag SF is first set to 0, and constant speed driving control is performed.

After this, is there any speed deviation, i.e. ■, ≧■5+△■
If the determination is NO, it is determined whether the vehicle is currently in fourth gear. When this determination is YES, the process returns to the constant speed running control step.

If the judgment above ■6≧■5+△■ is YES, 5
A determination is made as to whether F=1 or not, and if the determination is YES, the process returns to the step of constant speed running control.

If the judgment of above ■E≧■, +Δ■ is YES and the judgment of 5F-1 is NO, it means that you are driving in 4th gear and VA exceeds ■ for the first time, and in this case , downshift from 4th gear to 3rd gear, and shift SF to “1”
Then, the process returns to the step of constant speed running control described above.

On the other hand, the above judgment of ■E≧■5+△■ is No, and 5F=
When the determination of 0 is NO, the vehicle is running in 4th gear,
Since ■ became larger than ■5, it was shifted down to 3rd gear, and only after that downshift did ■□ become smaller than ■. At this time, from 3rd to 4th gear
Shift up quickly and set SF to 0.

After this, the set vehicle speed ■ is newly set to the new set vehicle speed, which is the value smaller than Δ■ (approximately 2 km/h when Δ■ is 3 km/h), and then set to the predetermined value. Constant speed driving control based on the newly set vehicle speed is performed until time Δt has elapsed. This △t means that the vehicle speed is ■, +△V (3km/
h) to Vs + 2km/h. After this Δt has elapsed, the set vehicle speed is returned to the original set vehicle speed, and the process returns to the first step of constant speed running control.

As explained above, according to the system of the present invention, when moving to constant speed driving in fourth gear, a new set vehicle speed as described above is temporarily set, so that the convergence of the vehicle speed is prevented. Stabilize quickly and quickly.

[Brief explanation of drawings]

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. 3 is a diagram showing the main parts of a constant speed traveling device according to an embodiment of the present invention. FIG. 4 is a sectional view showing the configuration of the actuator; FIG. 4 is a time chart illustrating an example of the constant speed cruise control of the present invention; FIG. 5 is a flowchart illustrating an example of the 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. Figure 1 Prefecture Figure 4 3 seconds 15 seconds

Claims (1)

[Claims] Shift switching means for shifting up and downshifting gears of an automatic transmission of an automobile; fuel supply control means for controlling the amount of fuel supplied to the engine; vehicle speed detection means for detecting vehicle speed; and maintaining the vehicle speed at a set vehicle speed. When the vehicle speed detected by the vehicle speed detection means increases by a predetermined value or more when traveling downhill, the shift switching means is operated to downshift. When the vehicle speed returns to a value equal to or less than the set vehicle speed plus the predetermined value, the shift switching means is activated to shift up and temporarily change the set vehicle speed to a value below the predetermined value. A constant speed running device for an automobile, comprising a control means for setting the value to a value added to the value.