An Integrated Numerical Tool for Engine Noise and Vibration Simulation 971992
The development of low noise engines and vehicles, accompanied by the reduction of costs and development time, can be obtained only if the design engineer is supported by complex calculation tools in a concurrent engineering process. In this respect, the reduction of vibrations (passenger comfort) and of vehicle noise (accelerated pass by noise) are important targets to meet legislative limits. AVL has been developing simulation programs for the dynamic-acoustic optimization of engines and gear trains for many years. To simulate the structure-born and air-born noise behavior of engines under operating conditions, substantial efforts on the mathematical simulation model are necessary.
The simulation tool EXCITE, described in this paper, allows the calculation of the dynamic-acoustic behavior of power units. EXCITE considers different excitations, as well as the nonlinear behavior of the crankshaft (stiffness and mass distribution depending on the crank angle) and of the slider bearings (elastohydrodynamic effects).
The simulation code of EXCITE was further improved, refined, and validated through cooperative effort between major European car manufacturers. The code was validated thoroughly by experimental tests on a reference powertrain, a FIAT 1.8-liter 4-cylinder gasoline engine. This paper describes the results obtained from the experimental tests.
The comparison between experimental and computed results shows that the level of accuracy attained with the use of this EXCITE is excellent.