Case study of automotive NVH topics induced by HVAC systems integration

Abstract

Within the automotive market, HVAC systems are of critical importance in ensuring passengers' thermal comfort inside the car cabin as well as complying with regulatory defogging functions. These systems involve various components such as blowers, thermal exchangers, actuators... over a wide range of well-known technologies and also innovations on newly introduced designs and products. Currently, within the established electrification trend worldwide, HVAC systems became one of the most important embedded systems, possibly inducing major contributions of noise and vibration. These NVH topics can emerge through various transfer paths inside the car cabin causing significant discomfort to passengers. During development and production stages, the NVH behavior at component level is mastered by both suppliers and OEMS according to internal standards and specifications. However, implementation into the complete vehicle can induce a specific NVH behavior unrelated to the compliance status at component level. Integration impact cases are highly reinforced within electrification trends as they involve more and more design changes with less technical background. Through a practical case study, this paper focuses on the NVH behavior induced by the integration of HVAC systems in the US market. Transfer paths analysis and solutions are investigated to improve the NVH behavior and set the product intrinsic limits giving the targeted vehicle.