Low Noise Engine Development

Nowadays power trains face an increased customer expectation regarding noise and vibration. This trend requires the use of simulation tools beginning in early phases of the development process to ensure a ‘low noise engine’ at the end of the development process. Therefore FEV is using virtual development methods for NVH optimization of power trains for more than ten years. Fully parameterized simulation models allow the utilization in all phases of the development. Depending on the current design status of the development the detailing of the simulation models can be adapted. Based on comparative simple rigid body models in the beginning decisions regarding engine global data like bore, stroke cylinder distance and positioning of balancer shafts can be made. Later on, when more design parameters are fixed the depth of simulation models is increased until a fully flexible model allows the prediction of the NVH behavior of the complete power train. Such a simulation is performed using a hybrid simulation approach based on Finite-Element and Multi-Body simulation. The FE model of the power train is loaded with excitation forces calculated with MBS in order to calculate surface velocity. Based on these results further simulation allows the simulation of the airborne noise radiation. Here, the simulated airborne noise simulation is combined with the so called virtual interior noise simulation (VINS) developed by FEV. This method allows a target-oriented engine development with focus on an excellent vehicle interior noise behavior. Within the scope of this paper the above described procedure is applied to a development of a gasoline inline four cylinder engine. The simulation methods are verified in each step of the development.