Study on the Influence Factors Upon the Propensity to Stick-Slip Phenomenon During Vehicle Start-Up Process

The vibration caused by the friction characteristic of the clutch during the vehicle start-up process has an impact on driveline torsional oscillation. This results in the occurrence of the stick-slip phenomenon which in turn aggravates the torsional oscillation. In this study, the dynamic model of the wet clutch was built and the self-excited vibration and stick-slip phenomenon during clutch engagement were theoretically analyzed and numerically simulated. The vehicle start-up driveline model was then built with consideration of the stiffness of the shafts, the time-varying mesh stiffness of the gear set, and system damping. The start-up process of the vehicle was simulated through the adoption of a constant engine speed control strategy, and the influence of the control and structure parameters on the stick-slip phenomenon during the vehicle start-up process was investigated. The results showed that increasing the relative speed threshold value of the constant engine speed control decreases the likelihood of the occurrence of the clutch stick-slip action, and the shaft stiffness, system damping, and inertia of each component also affect the stick-slip phenomenon during vehicle start-up.