Application And Research Of Noise Control Of Battery Fan Noise In Hybrid Automotive

As the key component of the hybrid vehicle, Battery needs a special cooling systemto keep the proper temperature. At present the battery with fan cooling system,whichinstalled in the truck, has been widely used in hybrid vehicle. The noise caused by thecooling system is enormous, which will influence the comfort of the passengers directly.In the paper, on the basis of system characteristics of the cooling system in hybridvehicle battery, the methods to reduce the interior noise of fan cooling system have beenpropose:(1) Conventional NVH methods to reduce the fan noise have been used, Thesemethods include insulation and sealing, sound absorption, damping and noise reductionand so on. By the use of sound-absorbing material, sealing holes, using insulation material,adding the damping on duct to reduce the pipeline derivative noise, the interior noise ofthe hybrid vehicle is greatly reduced. The noise reduction level are11.7dB(A) and10.5dB(A) in the driver’s inner ear and rear right passenger inner ear.(2) The noise of thefan is reduced by adjusting the fan speed: Under the premise of meeting the thermalmanagement system, the fan speed is adjusted according to vehicle speed, engine speed,and battery temperature. When the vehicle at a standstill or low speed condition, the fannoise can be reduced by lowering the fan speed since the battery is not heat. When thevehicle is at high speeds or acceleration condition, the fan speed can be increased whenthe interior noise of vehicle is relatively high and the battery is heat. The multi-fan-speedcontrol strategy is proved to be effective, and the fan noise contribution to vehicle interiornoise is small on various operating conditions.(3) By Changing the structure of the systemsuch as modifying grille of the inlet duct and improving exhaust duct thickness, the systemnoise can be reduced more than1.5dB(A).(4) Improved thermal management can alsoreduce the fan noise. System thermal management issues, such as the intake duct poorlydesigned, is pointed out and confirmed by experiments and simulation.By using the above control methods, the finally interior noise of the hybrid is reduced to asatisfactory level. When the vehicle is stationary and the engine is off, the interior noise isreduced from original51.1dB (A) to37dB (A), and the fan noise is almost imperceptible.Now the vehicle is at same noise level of the Prius and Civic.