Study on torsional vibration characteristics of crankshaft in variable displacement diesel engine

In order to investigate the torsional vibration characteristics of the variable displacement diesel engine and explore the best variable displacement schemes, a co-simulation model of a V6 diesel engine crankshaft system is built by using GT-SUITE software and validated by experiments. Various displacement schemes under 10%~50% of engine load are simulated respectively. The results indicate that the torsional vibration angle displacement amplitude of crankshaft under cylinder deactivation increases greatly, which mainly consists of low order rolling vibrations; the fuel cut-off scheme is better than the valve cut-off scheme with the same cylinder deactivation numbers, while the additional torsional vibration stress is slightly larger than the latter's. The fuel cut-off scheme with uniform firing interval has the best torsional vibrational performance.