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Automotive Engineering ›› 2025, Vol. 47 ›› Issue (2): 281-291.doi: 10.19562/j.chinasae.qcgc.2025.02.008

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Torsional Vibration Characteristic Analysis of Diesel Engine Range Extender Under Electromechanical Coupling

Jilin Lei1(),Xiongzhuan Yang1,Weichao Wang1,Yue Qiu1,Zhaoqian Yang1,Yuhua Bi1,Rui Mo2   

  1. 1.Kunming University of Science and Technology,Yunnan Key Laboratory of Internal Combustion Engine,Kunming 650500
    2.Kunming Yunnei Power Co. ,Ltd. ,Kunming 650500
  • Received:2024-05-20 Revised:2024-09-02 Online:2025-02-25 Published:2025-02-21
  • Contact: Jilin Lei E-mail:leijilin@sina.com

Abstract:

Torsional vibration of power system is a hot and difficult problem in NVH field of extended range electric vehicles. In order to investigate the torsional vibration characteristics of the range extender under electromechanical coupling, taking a diesel engine range extender as the research object, systematic quantification of the shaft system is carried out and a torsional vibration mechanical model of the eight-degree-of-freedom shafting system is established. A non-contact measurement method is used to conduct torsional vibration tests on the range extender platform to verify the accuracy of the model. The method of obtaining shafting structure parameters, electromagnetic parameters and excitation torque is discussed. The coupling calculation of the range-extender shafting is carried out and the comparison analysis with the original machine is made. It is concluded that the addition of the motor rotor system will reduce the natural frequency of shafting by 27.6Hz and the maximum amplitude by about 21%. The resonant speed is shifted forward by about 200 r/min on the basis of the original machine, and a natural frequency is increased in the first 12 steps. The influence of electromagnetic parameters on torsional vibration characteristics of shafting is analyzed according to the particularity of range extender working condition. The results show that the electromagnetic damping is linearly and negatively correlated with torsional vibration amplitude, but it does not change the natural frequency and resonant speed of shafting. The electromagnetic stiffness has no obvious effect on the amplitude of torsional vibration, and mainly affects the size of zero frequency, which will lead to low frequency rolling vibration of shafting.

Key words: range extender, torsional vibration, electromechanical coupling, dynamics