Speed change ratio controller for continuously variable transmission
AssigneeNissan Motor Co., Ltd.
InventorTatsuo Ochiai
Life of this patent
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Abstract
In a vehicle provided with a continuously variable transmission, when a target speed change ratio sharply decreases due to the release of an accelerator pedal from depression, a real speed change ratio of the continuously variable transmission which follows the target speed change ratio may undershoot the target speed change ratio. Due to this undershoot, the engine rotation speed may temporarily fall below a permitted level. Therefore, the variation rate of the speed change ratio of the transmission is decreased in the terminal phase of the shifting process of the speed change ratio.
Claims11
A control device for a continuously variable transmission for a vehicle, said vehicle comprising an engine for driving said vehicle, a throttle for varying a rotation output of said engine according to an opening thereof, an accelerator pedal for varying the opening of said throttle according to a depression thereof, and said continuously variable transmission varying the rotation output of said engine to a specified speed change ratio, said control device comprising:
- a sensor for detecting a degree of the depression of said accelerator pedal;
- and
- a microprocessor programmed to:
- calculate a target speed change ratio according to the degree of the depression of said accelerator pedal;
- vary the specified speed change ratio of said transmission to said target speed change ratio at a predetermined response sensitivity,
- determine if said accelerator pedal has been released from the depression based on the detected degree of the depression of said accelerator pedal, and
- decrease said response sensitivity during a process of changing over of said target speed change ratios before and after the accelerator pedal is released from the depression.
A control device for a continuously variable transmission for a vehicle,
- said vehicle comprising an engine for driving said vehicle, a throttle for varying a rotation output of said engine according to an opening thereof, an accelerator pedal for varying the opening of said throttle according to a depression thereof, and said continuously variable transmission varying the rotation output of said engine to a specified speed change ratio, wherein said control device comprises:
- means for detecting a degree of the depression of said accelerator pedal,
- means for calculating a target speed change ratio according to the degree of the depression of said accelerator pedal,
- means for varying the specified speed change ratio of said transmission to said target speed change ratio at a predetermined response sensitivity,
- means for determining if said accelerator pedal has been released from the depression based on the detected degree of the depression of said accelerator pedal, and
- means for decreasing said response sensitivity during a process of changing over of said target speed change ratios before and after the accelerator pedal is released from the depression.
Dependencies are inferred from the claim text.