Prediction Technology for Motorcycle Drivability Attributed to Drive Train Characteristics

The feeling given through the vibration, which is transiently generated by the body when the throttle is beginning to be opened, is one of the important factors that affect the quality of drivability in motorcycles. This feeling is usually evaluated by subjective ratings on actual motorcycles carried out by expert riders and the specifications are decided based on those results. In this research, the subjective rating was expressed as a formula and the simulation technology of behavior prediction was constructed for the parts associated with the drive train as well as the motorcycle body. The responding time delay, the magnitude of overshoot and the vibration frequencies were extracted as highly correlated factors with the evaluation results of subjective ratings through the analysis on the characteristics of longitudinal acceleration responses of the body to the magnitude of throttle opening. Transformation of subjective rating into the formula was carried out by making linear combination of those factors. In addition, the simulation technology to accurately predict longitudinal accelerations was created by adding modeling objects such as suspension, body frame and rider to the conventional simulation model composed of engine, drive train and tires. With these technologies, it was made possible to evaluate the motorcycle drivability associated with the drive train in early stage of the designing.