Vehicle Intermittent Idle Shake: Mechanism and Influence Factors

This paper studies the mechanism and influencing factors of the intermittent shaking of a vehicle in idle conditions and explores methods to suppress the idle shake of a vehicle. A full vehicle model including an engine crank-link mechanism is established. Taking a vehicle with intermittent idle shake as an example, the causes of the intermittent idle shake of the vehicle are investigated. The study shows that the intermittent idle shake of the vehicle is caused by the beat vibration, which is due to the unbalance of the crankshaft of the engine and the rotating turbine of the torque converter, and the near rotational speeds of these two rotating parts. In addition, a parametric model of cylinder pressure is presented. The effects of abnormal cylinder pressure (abnormal amplitude, abnormal ignition phase and abnormal fluctuating rate) on the idle shake are analyzed respectively. It is found that changes of combustion pressure in cylinder may also cause intermittent idle shake of the vehicle. Finally, the measures to attenuate the intermittent idle shake of vehicle are presented.