Method for controlling rate of change of ratio in a continuously variable transmission
View Patent ↗A method for controlling a rate of change of speed ratios in a continuously variable transmission (CVT) includes sensing a vehicle speed, sensing an engine speed, and sensing a change in a position of an accelerator pedal. The method includes determining a desired engine speed based on the change in the position of the accelerator pedal, the vehicle speed, and the engine speed. The method includes increasing a target engine speed at a first rate to a predetermined value, wherein the target engine speed corresponds to a speed ratio. The method includes measuring a difference between the target engine speed that is held at the predetermined value and an actual engine speed, and increasing the target engine speed to the desired engine speed at a second rate when the difference substantially equals a predetermined threshold, wherein the second rate is less than the first rate.
1. A method for controlling a rate of change of speed ratios in a continuously variable transmission (CVT), comprising:
sensing a vehicle speed;
sensing an engine speed;
sensing a change in a position of an accelerator pedal;
determining a desired engine speed based on said change in said position of said accelerator pedal, said vehicle speed, and said engine speed;
increasing a target engine speed at a first rate to a predetermined value, wherein said target engine speed corresponds to a speed ratio;
holding said target engine speed at said predetermined value;
measuring a difference between said target engine speed that is held at said predetermined value and an actual engine speed; and
increasing said target engine speed to said desired engine speed at a second rate when said difference substantially equals a predetermined threshold, wherein said second rate is less than said first rate.
2. The method of claim 1 further comprising determining a rate of change of engine speed necessary to attain said desired engine speed.
3. The method of claim 1 further comprising increasing said target engine speed to said predetermined value if a rate of change of engine speed necessary to attain said desired engine speed exceeds a predetermined rate.
4. A system for controlling a rate of change of speed ratios in a continuously variable transmission (CVT), comprising:
a first sensing module that senses a vehicle speed;
a second sensing module that senses an engine speed;
a third sensing module that senses a change in a position of an accelerator pedal; and
a control module that:
determines a desired engine speed based on said change in said position of said accelerator pedal, said vehicle speed, and said engine speed;
increases a target engine speed at a first rate to a predetermined value, wherein said target engine speed corresponds to a speed ratio;
holds said target engine speed at said predetermined value;
measures a difference between said target engine speed that is held at said predetermined value and an actual engine speed; and
increases said target engine speed to said desired engine speed at a second rate when said difference substantially equals a predetermined threshold, wherein said second rate is less than said first rate.
5. The system of claim 4 wherein said control module determines a rate of change of engine speed necessary to attain said desired engine speed.
6. The system of claim 4 wherein said control module increases said target engine speed to said predetermined value if a rate of change of engine speed necessary to attain said desired engine speed exceeds a predetermined rate.