Multi Disciplinay Optimization of Engine Suspension Stiffness
CHALLENGE - The engine suspension in a vehicle has the primary task to filter the car body from engine-generated vibrations, such as reciprocating mass and gas pressure forces. For idle vibrations, this is mainly achieved by tuning the engine mounts stiffness in order to set the system natural frequencies far enough from the frequencies of unbalanced orders. During car ride, though, the road induced excitations cause unwanted engine shaking, that may results in perceived discomfort for the passengers.
SOLUTION - The tuning requirements for the two cases (idle and ride engine shaking) often lead towards opposite choices. A multidisciplinary optimization on engine mount stiffness has been carried on modeFRONTIER and ADAMS/Car in order to identify the Pareto frontier for optimizing the tuning on 3 cylinder engine, considering idle vibrations and on-road engine shaking. A preliminary DoE has been used to train a set of response surfaces (RSM), on which a genetic algorithm has been employed to find the optimum.
BENEFITS - We could validate existing design criteria and establish new ones in terms of natural frequencies setting. We found an optmimum, respecting the given constraints. Further evaluations are in progress to decide whether the optimum is robust enough versus all other constraints and performances.