Abstract
Keywords:
NVH simulation, heavy duty engine, acoustic radiation
Abstract:
As vehicle noise certification legislation will become more and more severe, particular attention shall be paid to engine noise. In parallel, the need to continuously increase engine performance as well as decrease emissions level with higher cylinder pressure and injection pressure, leads to higher and higher contribution of combustion noise in the global noise radiated by the engine. Moreover, by considering loaded truck and lower engine speed range, new noise regulation will amplify this phenomenon. Consequently, acoustic development process will have to be as efficient as possible, to cope also with shorter and shorter engine project development time plan, more and more diversified projects (customer profiles, new acoustic comfort requests) and where weight benefit is important too. In this perspective, Volvo Powertrain develops acoustic simulation tools in order to improve engine NVH optimization process.
This paper describes the different steps of the method used inside Volvo Powertrain to simulate NVH behaviour of heavy duty engines. It includes finite elements modelisation and updating aspects, as well as engine internal excitations determination by experimental inverse method. Finally, vibration and acoustic calculation methods are presented. First simulations show encouraging results when correlated with measurements done in semianechoic engine test cell.