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The low running cost of electric two wheelers is resulting in high popularity and growing market share. The electric two wheelers are generally considered silent. However, the tonal nature of radiated noise is annoying for both driver and pedestrians in electric vehicles. This study focuses on electric two-wheeler with annoyance issue. The customer complained about non-linear noise with respect to speed and also whining during loading and coasting. The detailed Noise Source Identification (NSI) revealed that the noise is due to motor and transmission whine and structural resonances of chassis excited by this motor excitation during runup and gear whine orders during coasting when excitation by motor is absent. The motor mounting and chassis are structurally modified with suitable stiffeners and damping based on the results of modal analysis. The transmission gear geometry and contact pattern are optimized for transmission error reduction.

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.

The parameters such as lower noise levels, quietness, etc. of a vehicle has no longer remained the only driving features since the passenger car buyers are greatly influenced by the perception of the sound. In a scenario like this, the sound quality becomes of great importance especially for smaller diesel powertrains as they are more annoying than their gasoline counterparts. The idling noise is critical as its noise creates the first impression of the vehicle on the buyer. The Indian passenger car market is dominated by diesel cars equipped with smaller engines less than 2 liter capacity. Present work describes the methodology to formulate the equation for annoyance/pleasantness for the diesel powertrains used in Indian passenger cars. The index, Sound Annoyance Rating (SAR) developed through this work is significant for powertrain level target setting and benchmarking purposes.