Critical frequencies and acoustic emission of an automotive Variable Displacement Oil Pump: some numerical analyses and validations

Emanuela Ligarò, Riccardo Maccherini, Raffaele Squarcini

Pierburg Pump Technology Italy


The adoption of criteria aimed at improving the vibro-acoustic behaviour of products has assumed in recent years a growing importance. Such an attention is especially notable in the automotive field. The ability to predict those structural resonances at which there will be the maximum amplification, becomes crucial. In this paper, a study of prediction of most influential structural resonances for a variable oil pump is presented as a case example. As first step, a modal analysis has been performed, the calculation provides the list of natural frequencies together with the respective modes of vibration of the structure.

Next, an analysis of the sound emission generated by the pump as a consequence of the application of unitary impact forces to a set of chosen points on the structure, is given. The latter analysis gives an indication of what will be the critical frequencies of the acoustic emission of the pump, therefore a suggestion of where to act to reduce noise.

The simulation activity has been accompanied by an experimental activity as a validation support of the calculation results.

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