Automatic transmission control system for motor vehicle

• US 5,478,293 A
• Filed: 03/22/1994
• Issued: 12/26/1995
• Est. Priority Date: 03/23/1993
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yonezawa, Shirou
• Primary Examiner(s): Bonck, Rodney H.
• Assistant Examiner(s): KWON, TAI CHOON
• Application Number:
  US08/215,702
• Time in Patent Office: 644 Days
• Field of Search: 477/97, 477/107, 477/109, 477/110, 477/121, 477/80
• US Class Current: 477/110
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2510/0628 Inlet air flow rate
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16H 59/141 of rate of change of torque or torque demand
• CPC Class Codes: F16H 59/18 dependent on the position of the accelerator pedal
• CPC Class Codes: F16H 59/24 dependent on the throttle opening
• CPC Class Codes: F16H 59/40 Output shaft speed
• CPC Class Codes: F16H 59/74 Inputs being a function of engine parameters F16H59/14 takes precedence
• CPC Class Codes: F16H 61/04 Smoothing ratio shift
• CPC Class Codes: F16H 63/502 for smoothing gear shifts

Abstract

In an automatic transmission control system, the throttle opening of a throttle valve is adjusted in accordance with the acceleration opening of an accelerator pedal, a gear is determined on the basis of the adjusted throttle opening and the rotation speed of the output shaft of an automatic transmission, and the throttle opening is prohibited from following a variation of the acceleration opening during a gear shifting operation. The complexity of the gear shift control is thereby reduced, and the gear shift shock caused when a driver depresses an accelerator pedal during the gear shift is prevented.

Claims

1. An automatic transmission control system comprising:

an accelerator pedal;

an accelerator opening sensor for detecting a quantity of depression of the accelerator pedal;

intake air quantity adjusting means for adjusting a quantity of intake air to an engine;

an automatic transmission;

output-shaft rotation speed detecting means for detecting a rotation speed of an output shaft of the automatic transmission;

automatic transmission control means for determining a target gear in the automatic transmission based on the rotation speed of the output shaft and the quantity of the intake air; and

control means for controlling said intake air quantity adjusting means so as to prohibit an opening of said intake air quantity adjusting means from following an acceleration opening during a gear-shift operation of said automatic transmission control means.

2. The automatic transmission control system according to claim 1, wherein said control means for controlling said intake air quantity adjusting means operates to fix the opening of said intake air quantity adjusting means to an opening immediately before a gear shift during the gear-shift operation of said automatic transmission, irrespective of a variation of the acceleration opening.

3. The automatic transmission control system according to claim 1, wherein said control means for controlling said intake air quantity adjusting means operates to vary the opening of said intake air quantity adjusting means more slowly than the acceleration opening during the gear-shift operation of said automatic transmission, and to vary the opening of said intake air quantity adjusting means in accordance with a rate of change of the acceleration opening before and after the gear-shift operation.

4. The automatic transmission control system according to claim 1, wherein said control means for controlling said intake air quantity adjusting means prohibits the opening of said intake air quantity adjusting means from following the acceleration opening when the acceleration opening is reduced during a down-shift operation from high to low gear by said automatic transmission control means under a condition that the acceleration opening and the rotation speed of the output shaft are below preset values.

5. The automatic transmission control system according to claim 4, wherein said control means for controlling said intake air quantity adjusting means increases the opening of said intake air quantity adjusting means by a preset value of opening in response to an instruction from said automatic transmission control means when the acceleration opening is reduced during the down-shift operation from the high to low gear by said automatic transmission control means under the condition that the acceleration opening and the rotation speed of the output shaft are below preset values.

6. The automatic transmission control system according to claim 5, wherein said automatic transmission control means instructs said control means for controlling said intake air quantity adjusting means to increase the opening of said intake air quantity adjusting means by a preset value of opening during the down-shift operation under the condition that the acceleration opening and the rotation speed of the output shaft are below preset values, and starts the gear-shift operation after an engine output is changed in response to the instruction from said automatic transmission control means.

7. An automatic transmission control method for vehicles comprising the steps of:

adjusting a throttle opening of a throttle valve in accordance with an acceleration opening of an accelerator pedal;

determining a target gear in an automatic transmission based on the throttle opening and a vehicle speed;

maintaining the throttle opening at a fixed value during a gear shifting operation irrespective of a variation of the acceleration opening; and

controlling the throttle opening in accordance with the acceleration opening before and after the gear shifting operation.

8. The automatic transmission control method according to claim 7, wherein the fixed value is a value of the throttle opening immediately before the gear shift.

9. The automatic transmission control method according to claim 7, wherein during the gear shifting operation, the throttle opening is varied more slowly than the acceleration opening wherein, and before and after the gear shift, the throttle opening is varied in accordance with a rate of change of the acceleration opening.