Automatic change-gear control device for use in electromobile

Claim 1

In an vehicle having an inertia characteristic and being driven by an motor, which includes means for detecting an output torque of said motor and producing a correlated motor torque signal, means for detecting a vehicle speed of said electromobile and producing a correlated vehicle speed signal, and a control device for automatically controlling a gear position of a change gear device according to a gear-changing pattern having at least a small gear ratio and a large gear ratio, commensurate with the output torque and the vehicle speed thus detected, and means for detecting the selected gear and producing a correlated gear ratio signal; an automatic change gear control device, comprising: means for obtaining a vehicle output torque signal from said motor torque signal and said gear ratio signal; means differentiating said vehicle speed signal with respect to time for obtaining an acceleration torque signal from the variation in vehicle speed signal and the vehicle inertia characteristic; operational means for obtaining a load torque signal from a difference between said vehicle torque signal and said acceleration torque signal; means setting a fixed upper acceleration torque limit signal; means setting a fixed lower acceleration torque signal; means setting a fixed upper load torque limit signal; means setting a fixed lower load torque limit signal; means selecting the small gear ratio when said load torque signal and said acceleration torque signal are both below their lower limit signals; means selecting the large gear ratio when either one of said load and acceleration torque signals is larger than its upper limit signal; and means maintaining the selected gear ratio when said load torque signal and said acceleration torque signal are both below their upper limit signals, and when either one of said load and acceleration torque signals is larger than its lower limit signal.