Oilsumps, valve covers and distribution covers belong to the main noise radiating parts on modern engines. These parts have in common that they undergo velocity excitation at their fixation to the main engine structure. A method was developed to quantify the noise emission of the individual part using artificial excitation. This measurement technique allows the assessment of the parts and their mounting to the engine for efficient variant comparisons. The difficulty lies in the simulation of near to rigid boundary conditions of those parts and in the effective velocity excitation. A combination of reciprocal acoustic excitation and inverse force identification is used. The objects are excited by volume velocity sound sources. On the basis of a reciprocity relationship and inverse force identification the effective noise emission is quantified for spatially uncorrelated velocity excitation. A comparison of aluminium, plastic and rubber decoupled oilsumps is shown as an example.
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