Torsional vibration attenuation of a closed-loop engine crankshaft system via the tuned mass damper and nonlinear energy sink under multiple operating conditions

摘要

In recent years, nonlinear energy sink (NES), as a nonlinear dynamic vibration absorber (NDVA),has been widely studied due to its high robustness and broadband vibration attenuation effectiveness,compared with the traditional linear dynamic vibration absorber (LDVA). In the area ofcrankshaft torsional vibration reduction, the external excitation of a closed-loop crankshaft modelchanges with the variation of speed, which puts forward higher requirements for wide-bandtorsional vibration attenuation. This study attempts to explore the feasibility of NES replacingthe traditional linear tuned mass damper (TMD) for engine crankshafts in possible practical engineeringapplication by studying a four-cylinders diesel engine crankshaft. Firstly, a multiinertiasnonlinear closed-loop self-excited coupled oscillation model (M-NCSCO) of crankshaftis established, and the correctness of the model is verified through comparison with those fromexperiments. Based on this, the crankshaft is coupled with optimal TMD (O-TMD), general NES(G-NES), and optimal NES (O-NES), respectively. An improved Newmark–β method is proposed tosolve the nonlinear dynamic model numerically. The effects of NES and TMD on the vibrationattenuation behavior of the crankshaft are studied under different engine operating conditions(including power, injection timing, single cylinder flameout, and load). The results show that thevibration attenuation efficiency and robustness of G-NES are 7.90 and 3.47 higher than that ofO-TMD when considering the above four typical working conditions comprehensively. Afterfurther optimization of G-NES, the vibration reduction efficiency of O-NES is improved by 3.1compared with G-NES.