Transmission control system for and method of automotive vehicle with continuously variable automatic transmission
AssigneeNissan Motor Co., Ltd.
InventorsAkito Suzuki, Hiroshi Asano
Life of this patent
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Abstract
A transmission control system of an automotive vehicle with a continuously variable automatic transmission, comprises an electronic transmission control unit which detects an acceleration of a drive wheel of the vehicle, and compares the acceleration of the drive wheel to a predetermined acceleration value. The control unit operates to inhibit only the upshifting action by preventing a speed ratio of the continuously variable automatic transmission from being upshifted toward a speed ratio less than a predetermined upshift limiting threshold.
Claims18
A transmission control system for an automotive vehicle with a continuously variable automatic transmission whose speed ratio is defined as a ratio of transmission input to output speed and is changeable continuously depending on vehicle speed and engine load, comprising:
- a hydraulic actuator producing a regulated line pressure and a speed change control pressure necessary to adjust the speed ratio hydraulically;
- and
- an electronic transmission control unit including a data processing section that performs:
- (a) detecting an acceleration of a drive wheel of the vehicle;
- (b) detecting a vehicle speed;
- (c) controlling the transmission such that an upshifting action occurs by decreasing the speed ratio as the vehicle speed increases;
- (d) comparing the acceleration of the drive wheel to a predetermined acceleration value;
- and
- (e) inhibiting the upshifting action by preventing the speed ratio of the continuously variable transmission from being upshifted toward a speed ratio less than a predetermined upshift limiting threshold when the acceleration of the drive wheel is greater than the predetermined acceleration value.
A transmission control method of an automotive vehicle with a continuously variable automatic transmission whose speed ratio is defined as a ratio of a transmission input to output speed and is changeable continuously depending on vehicle speed and engine load, comprising the steps of:
- (a) detecting an acceleration of a drive wheel of the vehicle;
- (b) detecting a vehicle speed;
- (c) controlling the transmission such that an upshifting action occurs by decreasing the speed ratio as the vehicle speed increases;
- (d) comparing the acceleration of the drive wheel to a predetermined acceleration value;
- and
- (e) inhibiting the upshifting action by preventing the speed ratio from being shifted toward a speed ratio less than a predetermined upshift limiting threshold when the acceleration of the drive wheel is greater than the predetermined acceleration value.
Dependencies are inferred from the claim text.