Abstract
Noise has important influence on customer's perception of vehicle quality. Research and development have been conducted to investigate the vehicle hearing. Heating, Ventilation and Air Conditioning (HVAC) noise generation and transmission mechanism. Reduction of HVAC noise has become an increasingly important task in automotive industry as requirements for passenger compartment comfort increase, and other components such as engine, exhaust system, etc., are made quieter. However, the aim of the present work is to study the performance of a vehicle interior noise produced by its air condition system. The vehicle used in these tests is Renault Megane, where the interior noise was measured at the driver's head position in terms of Sound Pressure Level (SPL). The experimental work had been done using B&K multi-channel analyzer. In addition, single number of the vehicle cavity air natural frequencies are calculated based on the well known acoustical wave equation.
The major contributors in the HVAC system airborne noise are compressor and handling unit that produce aerodynamic, hydraulic and mechanical noises. Since the HVAC's fan is driven direct the vehicle battery, i.e., separate from the HVAC, therefore, it's noise generation can be obtained directly by putting the HVAC OFF and the fan ON. Meanwhile, the hydraulic and mechanical noise can be obtained by extracting the airborne noise with disengaged compressor with the fan ON from that with engaged compressor with the fan ON. The results indicate that a significant information can be gained in order to improve the vehicle interior quietness.
Keywords: Heating, Ventilation and Air Conditioning (HVAC), Sound Pressure Level (SPL), aerodynamic noise, hydraulic noise, mechanical noise.