JPH01229145A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To eliminate the occurrence of a shock and an engine stall by providing a means for detecting the sudden deceleration of a vehicle, and by shifting the downshift point toward the high vehicle speed side at the time of sudden deceleration. CONSTITUTION:A deceleration calculating means 2 calculates deceleration by the variation of pulse number from a vehicle speed detecting means 1. A downshift point calculating means 4 calculates and sets the downshift point (vehicle speed) in accordance with deceleration. A speed change control means 6 determines and promotes the speed change by both a speed-change pattern and the downshift point to control an automatic transmission 7. In accordance with deceleration, the downshift point at the time the throttle has been fully closed is shifted toward the high vehicle speed side, and the downshift is carried out from the above speed change point. Thus, such problems as the occurrence of a shock due to a speed change after stoppage of the vehicle, and the occurrence of engine stall due to a strong braking action applied to the engine can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a speed change control device for an automatic transmission.

(Prior Art) As a conventional shift control device for an automatic transmission, for example, "Nirasan Full Range Electronically Controlled Automatic Transmission RIE4RO Type A Maintenance Manual" (A261CO
7, March 1988).

(Problem to be Solved by the Invention) However, in such a conventional shift control device for an automatic transmission, the shift point (shift pattern) is changed by a manual switch, or the shift point (shift pattern) is changed automatically by the accelerator depression speed. However, since the downshift point when the throttle is fully closed is basically fixed, the actual shift may be caused by a delay in deciding to shift (delay in vehicle speed measurement, etc.) or a delay in hydraulic pressure. Due to the delay in the response of At times, the engine would be pushed down from the drive wheels, potentially making it more likely to stall.

(Means for Solving the Problems) This invention improves on such conventional technology by moving the downshift point when the throttle is fully closed to the high vehicle speed side according to the deceleration, and It is designed to downshift.

(Function) As described above, according to the present invention, when decelerating, the downshift point is moved to the high vehicle speed side according to the deceleration, so that the downshift point is moved to the high vehicle speed side in accordance with the deceleration. This solves problems such as jerking when shifting gears or stalling due to strong braking applied to the engine.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

First, to explain the configuration, the vehicle speed detection means 1 receives a pulse signal from a sensor provided on the output shaft for a predetermined period of time (for example,
100m5) and calculates the vehicle speed.

The deceleration calculating means 2 calculates the deceleration based on the change in the count value of the number of pulses from the vehicle speed sensor within a predetermined time (for example, 354 m5), and this may be detected by a longitudinal G sensor. The brake operation detection means 3 detects whether or not a brake operation is being performed by a brake inch, and is provided for fail-safe purposes, so it does not necessarily need to be provided.

The downshift point calculation means 4 calculates and sets a town shift point (vehicle speed) according to the deceleration, and the shift control means 6 controls the shift pattern and the downshift point in response to the conventional human input signal 5. The automatic transmission 7 is controlled by determining and advancing the gear change.

The specific circuit configuration is the same as before, but the front and rear G
Sensor and flake input may also be added.

Next, the effect will be explained.

The method of calculating deceleration will be explained with reference to FIG.

First, the counter C is incremented one by one by the human power of pulses from the vehicle speed sensor.

Further, the counter C is cleared every unit time (for example, 100 m5 or 354 m5), and the value before being cleared becomes a value proportional to the vehicle speed.

In the process for each unit time, a difference ΔC (proportional to deceleration) between the latest counter value C and the previous counter value C' is calculated, and then the counter value C' is updated to the new C'. Next, counter C is cleared and the process ends.

Note that it is also possible to detect deceleration using a longitudinal G sensor.

Next, control of the downshift point will be explained with reference to FIG.

First, the deceleration △C is read by the deceleration detection means,
Minimum vehicle speed VSP at downshift point corresponding to △C 43
(4-3 Tau 7), VSP 32 (3→2 down), and VSP 21 (2→1 down) are looked up from the table (for example, FIG. 4).

A conventional shift decision is made along the shift line modified by the minimum vehicle speed at the downshift point.

Note that the upper limit of the minimum vehicle speed is also preferably set to the vehicle speed when the corresponding upshift is fully closed. That is, VS
The upper limit of P43 is the vehicle speed at the 3→4 up point.

(Effects of the Invention) As described above, according to the present invention, the downshift point is moved to the high vehicle speed side during deceleration, so that the vehicle stops due to a delay in the shift timing. This has the effect of solving problems such as shifting after shifting and causing jerking, or strong braking being applied to the engine, causing the engine to stall.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIGS. 2 and 3 are flowcharts showing the operation of the present invention, and FIG. 4 is an example of data used in the present invention. 1 ・Vehicle speed detection means 2 ・Deceleration calculation means 3
- Brake operation detection means 4 - Downshift point calculation hand 5 - Conventional human power signal 6 Shift control means 7 -
・Automatic transmission patent applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Akatsuki Sugimura Representative Patent Attorney Oki Sugimura 2nd (l Mars Shin @ 1: Shima Warikoke 9 Figure ('°Z Akitomo) Figure 3 5TAR lower (when commuting): 2 324 r---, --, -J A speed-C:, / ,. Mouth IM-2/ , / Readingsha included ・ l
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Claims (4)

[Claims] 1. A shift control device for an automatic transmission capable of switching shift points, comprising means for detecting sudden deceleration of a vehicle, and shifting a downshift point to a high vehicle speed side in the event of sudden deceleration. Device. 2. An automatic gear shift characterized in that the sudden deceleration detecting means according to claim 1 is a means for detecting the speed of the vehicle, and a sudden deceleration is determined when a change in vehicle speed per unit time exceeds a predetermined value. Machine speed control device. 3. A shift control device for an automatic transmission, characterized in that the sudden deceleration detection means according to claim 1 is used as a deceleration detection means, and a downshift point is moved to a higher vehicle speed side in accordance with deceleration. 4. In the device according to claims 1 to 3,
A shift control device for an automatic transmission, characterized in that a limit of movement of a downshift point to a higher vehicle speed side is set as a corresponding upshift point.