Sound Quality Evaluation of a Brake and Clutch Pedal Assembly used for Automotive Applications

Sound Quality (SQ) of brake and clutch pedal assembly plays an important role in contributing to vehicle interior noise and perception of sound. Quiet operation of brake and clutch units also reflects the vehicle built and material quality. Noise emitted from these sub-assemblies has to meet certain acceptance criteria as per different OEM requirements. Not much work has been carried on this over the years to characterize and quantify the same.

An attempt has been made in this paper to study the sound quality of brake and clutch pedal assemblies at component level and validate the same by identifying the parameters affecting SQ. Effect on noise at different environmental conditions was studied with typical operating cycles in a hemi-anechoic chamber. The effect of sensor switches integrated within the clutch and brake pedal on sound quality is analyzed. It is found that the operating characteristics of switches drives the noise and SQ. Wavelet analysis was carried out to correlate loudness sound quality metric with time-frequency amplitude modulations.

Jury evaluation was performed to correlate subjective to objective data. Structural modifications were then suggested to improve the perception of sound. Significant improvement in the brake and clutch pedal assembly sound quality was achieved in product development with marginal impact on cost.