Abstract
In order to improve the vibration characteristics of full vehicle at idle, experimental and theoretical studies have been carried out. Idle shake in D range occurs by various reasons such as body bending characteristics, resonance with subsystems, and engine mount characteristics, etc. Using full vehicle FE analyses and modal tests, we introduce the way to improve the idle shake in the early design stage. As a result, it shows that the exciting forces are the engine 2nd order torque/force and the P/T modes are entirely changed by additional boundary conditions of drive line. Moreover the frequencies of subsystems arranged to be lined up at the idle frequency range in order to avoid the resonance with subsystems. Also to reduce the idle shake, a hydraulic mount which is optimized by phase shift method is applied to the rear engine mount .