2 . the principle that cylinder misfire is diagnosed using torsional vibration harmonic analysis is illustrated by calculation of vectorsummation . calculation and experiment show : low harmonic will increase highly and main harmonic will decrease little when one cylinder is misfiring 通过对扭振激励的相对振幅矢量和的仿真和实验研究，得到结论如下：如果柴油机发生单缸熄火故障，扭振低谐次幅值会大幅度增加，主简谐会略有下降。
