Electronic continuously variable transmission (ECVT) system and control method for the same

An electronic continuously variable transmission (ECVT) system, applicable to a motorcycle, the ECVT system comprising:

• a first speed sensor, disposed in a front portion of the motorcycle, to sense a front-wheel speed of the motorcycle and send a first speed signal;
• a second speed sensor, disposed in a rear portion of the motorcycle, to sense a rear-wheel speed of the motorcycle and send a second speed signal;
• a continuously variable transmission (CVT) for transforming and transmitting a driving power of an engine of the motorcycle to a rear wheel of the motorcycle;
• and
• a control unit, electrically coupled to the first speed sensor, the second speed sensor and the CVT, to receive a user control signal and accordingly control a speed-changing state of the CVT,
• wherein, in a manual-operation mode of the motorcycle, the user control signal is a shift request signal, and the control unit is configured to:
• predict, according to the shift request signal, the first speed signal and the second speed signal, whether a next gear indicated by the shift request signal will cause the motorcycle to move unsteadily,
• ignore the shift request signal such that the CVT does not perform gear shifting if the control unit predicts that the next gear indicated by the shift request signal will cause the motorcycle to move unsteadily, and
• send at least a shift control signal to the CVT so that the CVT performs gear shifting if the control unit predicts that the next gear indicated by the shift request signal will not cause the motorcycle to move unsteadily;
• wherein the shift request signal indicates a down transmission request, and the control unit is configured to:
• set an engine rotation speed threshold according to the shift request signal, the first speed signal, and the second speed signal;
• and
• determine whether an engine rotation speed of the motorcycle is greater than or equal to the engine rotation speed threshold so as to predict whether the next gear indicated by the shift request signal will cause the motorcycle to move unsteadily;
• wherein the control unit predicts that the next gear indicated by the shift request signal will cause the motorcycle to move unsteadily if the engine rotation speed of the motorcycle is greater than or equal to the engine rotation speed threshold;
• and the control unit predicts that the next gear indicated by the shift request signal will not cause the motorcycle to move unsteadily if the engine rotation speed of the motorcycle is less than the engine rotation speed threshold;
• wherein the ECVT system further comprises an inclination angle sensor electrically coupled to the control unit, and the control unit sets the engine rotation speed threshold based on a signal sent from the inclination angle sensor.