JPS6299219A - Constant speed running device for automobile - Google Patents

Abstract

PURPOSE:To prevent a vehicle from hunting, by providing such an arrangement that the vehicle is shifted down after a first set time elapses when the vehicle speed exceeds a set vehicle speed by a predetermined value during the vehicle running down on a slope, and the vehicle is shifted up after a second set time which is longer than the first set time elapses when the vehicle speed comes to be below a predetermined speed. 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 DELTAV, a control device 11 delivers a signal to an automatic speed change gear 21 after a first set time DELTAt1 elapses so that a vehicle is shifted down. Further, when the vehicle speed VA is less than the set value VS+DELTAV, the vehicle is shifted up after a second set time elapses. In this case the second set time DELTAt2 is set to be longer than the first set time DELTAt1. For example, there is set such a condition as DELTAt1=3sec. DELTAt2=15sec. With this arrangement, it is possible to prevent hunting during shift-up and shift-down.

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 may not be as effective on hills, and the vehicle speed may increase significantly 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, 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, , there is a problem in that downshifts and upshifts occur successively, 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 downshifting and upshifting of an automatic transmission even when the automobile is traveling at a constant speed downhill. It is something to do.

(Means for Solving the Problems) As shown in FIG. 1, the constant speed traveling device for a motor vehicle of the present invention includes a shift switching means for shifting up and downshifting the gear stage of an automatic transmission a of a motor vehicle. , a fuel supply control means d that controls the amount of fuel supplied to the engine C, a vehicle speed detection means e that detects the vehicle speed, and controls the fuel supply control means to maintain the vehicle speed at the 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 when driving on a hill, the shift switching means is operated to downshift after a first set time, and the vehicle speed is changed to the set vehicle speed. When the vehicle speed returns to a speed equal to or lower than the predetermined value added to the predetermined value, the control means g operates the shift switching means to shift up after a second set time. 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 on a downhill slope while traveling at a constant speed, the first setting When the automatic transmission is downshifted after a period of 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 installation 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 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 bag @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 temporarily stores various data. Random Access Memo IJ (RA)
M). This control device 11 receives 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.
Further, the control device 11 outputs a signal 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 to the vehicle speed indicated by the signal from the vehicle speed sensor 7, for example. When the vehicle speed is within the range of +n/h from 40 to 100, by operating ○N when the desired vehicle speed is reached,
The vehicle speed at that time is set as the set vehicle speed for constant speed driving. Also, the coast switch 17 is used when decelerating while driving at a constant speed, and is ON! Vehicle speed decreases during production. Further, when the constant speed running control is canceled due to a reason other than the 0FFff1 operation of the main switch 14, the resume switch 18 is turned on to return 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. 21
, a signal is output to decelerate or restore the speed. Also, when driving at a constant speed, on a downhill slope,
Based on the output of the vehicle speed sensor 7, if the vehicle speed increases by a predetermined value or more than the set vehicle speed, the automatic transmission 21
A shift-down signal Sd is output to.

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 the inside of the casing 26 is made airtight from the outside by a rubber diaphragm 27. The diaphragm 27 is biased toward the atmospheric chamber 30 by a spring 31 disposed within the negative pressure chamber 28. In addition, a negative pressure introduction solenoid valve 51 for controlling the introduction of negative pressure into the negative pressure chamber 28 and an eleventh second atmosphere introduction solenoid valve 52,53 (second atmosphere introduction solenoid valve) are provided on the end face of the casing 26. 53
(not shown).

A rod 32 connected to the diaphragm 27
is slidably held by a bearing part 33 provided in the casing 26 and protrudes to the outside through the atmospheric chamber 30, and the throttle valve is provided in the intake passage of the engine via a wire 34. 35, and operates the throttle valve 35 in the opening direction when the diaphragm 27 moves in the Δ direction (toward the negative positive chamber 28 side).

Further, the negative pressure introducing solenoid valve 51 opens a passage 51b, which has one end connected to the negative pressure introducing vibe 36 guided from a negative pressure source and the other end communicates with the negative pressure chamber 28, with a valve body 51c. This valve body 51c is configured to shut off the spring 51. d so as to block the passage 51b, and when the solenoid 23a is energized, it is moved against the spring 51d to open the passage 51b. Similarly, the first atmosphere introduction solenoid valve 52 (the same applies to the second atmosphere introduction solenoid valve 53) has one end open to the atmosphere and the other end connected to the negative pressure chamber 28.
The valve body 52C opens and closes the passage 52b communicating therein, and the valve body 52C is tensilely biased by a spring 52d to open the passage 52b.
When the solenoid 23b is energized, the passage 52b is blocked against the spring 52d. and,
The solenoids 23a, 23b, 23C in these solenoid valves 51, 52, 53 are connected to the control device 1 shown in FIG.
1 controls the negative pressure in the negative pressure chamber 28 of the actuator 23, and the opening of the throttle valve 35 is controlled by displacing the diaphragm 27 in accordance with this negative pressure. is now under control.

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.
If 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 will be set.
, is set in the RAM of the control device 11, and thereafter, while comparing this set vehicle speed and the actual vehicle speed (■) indicated by the signal from the vehicle speed sensor 19, the actual vehicle speed (4) is set to the set vehicle speed (2). A signal is output from the control device 11 to the actuator 23 to make them match.

In other words, when the actual vehicle speed ■ becomes lower than the set vehicle speed ■, the control device 11 sends the negative pressure introduction solenoid valve 51 and the first atmosphere introduction solenoid valve 52 to the actuator 23.
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 closes and the first solenoid valve 52 opens, and the air inside the negative pressure chamber 28 is Negative pressure is reduced.

Therefore, the diaphragm 27 is displaced in the anti-Δ direction and the throttle valve 35 is operated in the closing direction, thereby reducing the actual vehicle speed to match the set vehicle speed. still,
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 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 (2) will significantly exceed the set vehicle speed (2) 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 ■ exceeds the set vehicle speed ■ by more than a predetermined value △■, the control device 11 operates to shift the speed from 4th gear after △t1 hour. When the actual vehicle speed becomes smaller than Vs+△■ by downshifting to 3rd gear, the driver shifts from 3rd to 4th gear after △t2 hours to maintain constant speed driving. At the same time, hunting between the fourth gear and the third gear is prevented by the action of Δt11Δt2. Hey, △j, = 3se
c.

It is desirable to set Δt2=about 15 seconds.

Next, details of the vehicle speed control will be explained with reference to the flowchart shown in FIG. In this control, we will proceed with the discussion assuming that ■5+△■ is again set as ■5. In the following description, "SF" indicates a shift flag, and when 5F=1, it indicates third speed, and when 5F=O, 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. VA VS ≧0?
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.

When the judgment of v, -Vs≧0 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 V, -V, ≧0 is YES and the judgment of 5F=1 is NO, it means that you are driving in 4th gear and have exceeded ■9 or ■5 for the first time. Sometimes, the timer is started, and after 3 seconds have elapsed, the gear is downshifted from the fourth gear to the third gear, and then the SF is set to "1" and the process returns to the constant speed running control step.

On the other hand, if the above judgment of V, -V5≧0 is NO, 5F=
When the determination of 0 is No, the vehicle is running in 4th gear,
Since VA has become larger than Vs, shift down to 3rd gear. This means that ■^ becomes smaller than Vs for the first time after the downshift. At this time, start the timer operation, and after 15 seconds have elapsed, Shift up from 3rd speed to 4th speed, set SF to O, and return to the 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 time after satisfying predetermined setting conditions, so that the shift change is performed after a predetermined period of time after a predetermined setting condition is satisfied. Shift hunting can be prevented.

[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 - of; -12 and 1'2 volumes (no knee changes) Figure 1 Figure 4 Figure 3F) 6 seconds procedural amendment (method) 1. Display of case 1985 patent application No. 23862
No. 7 No. 2, Title of the invention Constant speed running device for automobiles 3, Relationship to the case of the person making the amendment Name of applicant (313) Mazda Motor Corporation 4, Agent

Claims (2)

[Claims] (1) Shift switching means for shifting up and downshifting the gear stage of the automatic transmission of the automobile, fuel supply control means for controlling the amount of fuel supplied to the engine, vehicle speed detection means for detecting the vehicle speed, and setting the vehicle speed. The fuel supply control means is controlled to maintain the vehicle speed, and when traveling downhill,
When the vehicle speed detected by the vehicle speed detection means increases by a predetermined value or more than the set vehicle speed, after a first set time,
When the shift switching means is operated to downshift and 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 to shift up after a second set time. A constant speed traveling device for an automobile comprising means. (2) A constant speed traveling device for an automobile according to claim (1), wherein the second set time is longer than the first set time.