Abstract
The stumble (abrupt and big acceleration decrease) occurring in manual transmission vehicle while standing start is analyzed by simulation model. This model was verified by comparing to test results. Mechanism of the stumble is clarified by analyzing simulation results and the key mechanism of the stumble is angular vibration of powertrain including wheel and tires. As a result, several method that can reduce the stumble is proposed by carrying out parametric study, increasing low end torque of engine, increase gear ratio etc.