The Heating Ventilation and Air Conditioning system (HVAC) is a compact and complex system designed to provide thermal comfort inside the car cabin. The system is composed of various components: fan, flaps, thermal exchangers, filters and specific turned ducts allowing thermal conditioning and airflow distribution to car cabin areas. Nowadays, as thermal engine noises are reduced and electrified car sales are increasing, the HVAC could be a major noise source inside the car cabin that could induce significant discomfort to passengers. HVAC noise issues are well known and solved. Many of them are related to the fans’ electrical motor, such as ticking and harmonic noises. The remaining noises are mainly aeroacoustic linked to the fan and interactions between HVAC components and airflow. HVAC behavior also consists of transfer paths and acoustic transparency responsible of emerging noises.
As an automotive system supplier, Valeo aims to provide acoustic comfort inside the car cabin by reducing HVAC noises during its operation. To do so, considering current HVAC designs, experimental investigations are conducted based on two strategies: passive absorbers on HVAC body and ducts, HVAC integration in the vehicle. In this paper, the HVAC system is described and the main acoustic and vibration issues encountered are presented. Then, the investigations conducted to reduce HVAC noise are shared and the results are discussed.