Sound quality refinement and vibration reduction during Horn Application in Electric Vehicles

This paper focuses on the cabin sound quality refinement and the tactile vibration reduction during horn application in the electric vehicle. Horn cracking sound is perceived in the cabin while pressing the horn. Higher vibrations are also perceived in accelerator pedal during the particular event. Sound diagnosis is carried out to identify the frequencies contributing to cracking noise. Transfer path analysis is conducted to identify the nature of noise and the predominant path through which forces transfer. Based on finding from TPA, various recommendations are evaluated which reduced the noise to a certain extent. Operational Deflection Shape(ODS) is conducted on the horn, horn mounting bracket and on the body to identify the component having higher deflection at the problematic frequencies . Based on the outcome of ODS, recommendations like dynamic stiffness improvement on the horn bracket and the body is assessed and the effect of each outcome is discussed. With all the recommendations proposed ,the cabin noise levels are reduced by ~ 5 dB (A) and the accelerator pedal vibration levels are reduced by ~ 40% . Sound quality parameter which needs to be considered during the horn selection is explained. The modal criteria which needs to be considered during development phase to avoid the horn cracking noise and tactile vibration is also proposed.