Numerical analysis and improvement of torsional vibration of shaft systems for engine with cylinder deactivation

Liu Xiaoyong, Su Tiexiong, Zhang Yi

COMPUTER MODELLING & NEW TECHNOLOGIES 2014 18(2) 76-82

School of Mechanical and Power Engineering North University of China, Taiyuan City, Shanxi Province, China, 030051

Cylinder deactivation is one of effective ways to improve fuel economy of engine, but will lead to changes in torsional vibration characteristics of shaft systems for engine. A lumped parameter model of torsional vibration of shaft systems for engine with cylinder deactivation was established, the numerical computing method was determined, harmonic analysis was engaged for the excitation torque of single cylinder. Based on these studies, torsional vibration of a V8-engine was analysed, the natural frequency results was verified by comparing with that of utilizing software AMESIM. The forced vibration results show that the torsional angle displacement of crankshaft under cylinder deactivation increases obviously, which mainly consists of the 2rd order rolling vibrations, but torsional stress decreases little. In order to control the rolling vibration, the measure of increasing the rotational inertia of the flywheel was adopted. The results after the adjustment show that the vibration of crankshaft was under control. In a word, the method is feasible and referred.