Hybrid Electric Vehicle Vibration, Noise, and Control

This chapter introduces the basics of vibration and noise, and addresses the unique vibration and noise characteristics and issues associated with electric powertrains, drivelines, and vehicle vibrations. In engineering noise and vibration control, understanding how sound waves are transmitted through panels is essential, and an associated measured quantity is the sound transmission loss (TL) through a panel. Compared with noise, vibration relates to oscillatory motion in fluids, vibration deals with oscillatory motion in solids. Hysteretic damping is most relevant to engineering noise and vibration control. Engineering experiments show that hysteretic force is proportional to the displacement but it is in phase with the velocity. Noise, vibration, and harshness (NVH) refinement is an important traditional task in powertrain development and the vehicle integration process. The chapter discusses some unique vehicle NVH challenges inherent in the operation of hybrid electric vehicles and addresses the unique NVH characteristics and associated control techniques.