Simulation Study of CVT Ratio Control for Engine Braking

The properties of auxiliary brake and the influences of auxiliary brake to car performance are introduced. The engine brake characters and its influence factors are explained, and the engine brake performance experiment is expounded. It is discussed that the necessity of control CVT ratio during engine braking. The conception of setting vehicle velocity during engine brakes is proposed, the engine object speed is estimated through the setting vehicle velocity, the object ratio of CVT is calculated with the engine object speed. With PID algorithm, the current ratio tracks the object one. This method solves the problem of difficulty to confirm object engine speed without throttle opening signal inputs. Finally, a simulation model of car with CVT is established, the simulate result shows that the CVT ratio control strategy during engine braking is valid.