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Many design philosophies have been used to design engine mount systems. One is to place the stiffness roll axis coincidental to the torque axis (crankshaft), to produce pure roll under static torque. Another is to focus the mount system to align with the inertial roll axis and uncouple dynamic roll. Recent trends have been to abandon mount system focusing as a criterion, in favor of controlling the six natural frequencies of the powertrain on the mount system. This paper discusses a technique to focus the mounts to uncouple the dynamic matrix, as much as possible within design constraints, while also maintaining control of the powertrain rigid body natural frequencies. Using engine mount system focusing to uncouple the dynamic matrix reduced lateral shake in an experimental vehicle. This reduction in vehicle shake was substantiated by total vehicle system models, experimental measurement, and subjective evaluation.

ADAMS (AUTOMATED DYNAMIC ANALYSIS OF MECHANICAL SYSTEMS) computer program is an excellent tool for solving non-linear, large-displacement dynamic problems. The suspension abuse events, e.g., curb, chuck hole, railroad ties and rough road impacts involve non-linear, large displacements of suspension components. ADAMS program and user written force subroutines are used to simulate these events. The modeling techniques to simulate these abuse events assume a simple tire model (spring and damper). Simulation results are presented in the form of computer generated outputs of forces, accelerations, velocities and displacements. Additionally, computer graphics is used to animate the vehiclegraphically during theabuse event. Specifically, the program is used to determine peak loads in suspension components during these events and these peak loads can be used as input loads for finite element analysis of suspension components.