Objective Metrics for Automotive Refrigerant System Induced Transients

Automotive refrigerant system induced noise and vibration transients usually accompany A/C compressor engagement/disengagement. These transients include audible/perceivable metallic impact/slip (clink, chirp, etc.), engagement thump, delayed accumulator thump, orifice tube/TXV induced hiss, and occasionally very loud slugging. In this paper, the inherent noise source mechanisms of these transients are described, and a set of psychoacoustics based objective metrics quantifying these transients in terms of loudness and sharpness is developed. Some of the recommended design-fixes and noise control approaches for the related transient noises are also discussed.