Objectification of the quality impression of a heavy duty vehicle, related to the noise generated by the engagement of new air compressor concepts. Towards validation criteria for compressor suppliers English Free

New constraints like fuel economy or emissions have given a significant impetus to development of new energy saving technologies in the field of air compressors for diesel engines. This has led to new and complex types of noise that can cause a bad quality impression, and even sometimes be so critical that customers can imagine that their vehicles have mechanical defects. Indeed, without objectively being necessarily of high acoustic intensity, air compressor contribution to exterior noise can be subjectively described as “metallic”, “fluctuating”, “not smooth” or “rattling”. An original process for assessing the influence of the noise generated by air compressors on the quality impression of heavy duty vehicles – in terms of exterior noise – has thus been implemented, the socalled objectification of perception. This has enabled to clearly identify and sort out the different root causes of issues faced with some new technologies of air compressors, and threshold values for each aspect of noise to validate new concepts or technical countermeasures. Criteria depending on overall noise and low frequency noise, mechanical noise, rattling noise and ticking noise were found by the regressive analysis.