Vibration Isolation of a Pick-up Vehicle with a 2-Cylinder Diesel Engine

With a very low firing frequency of a 2-cylinder diesel engine with 180° phase difference, control of Idle-shake of a pick up vehicle became a challenging task. It was reduced with all 3 engine mounts focused on a Torque-roll axis of the power train. Simulation of rigid body dynamics determined specific mount stiffness in compression and shear. Decoupled engine mount system resulted into also smooth key off of the vehicle. Nonlinear force deflection characteristics of all the rubber mounts ensured optimum design for vibration isolation of the frame, controlled motion of the power train in panic braking and adequate fatigue life of the rubber mounts on Torture Tracks. Sensitivity of front mount position, balance of all 6 rigid body modes and influence of exhaust system flexibility were found to be critical parameters for consistency in performance of production vehicles.