Noise signatures of brake vacuum booster and their acoustic treatment

摘要

Automotive brake system can be broken down to brake actuation and foundation. Each is composed of number of components connected by brake lines. Both actuation and foundation contribute to objectionable audible noises. Audible noise has been an important part of the functional requirement and will be critical to product perception as the vehicle powertrain becomes quieter, particularly in hybrid and electric plug-in platforms. Such a noise is now considered to be a reflection of the quality level of the vehicle engineering level from the consumers' perception, and can affect maintenance and warranty cost. Customers associate vehicle quality with how quiet the vehicle is. Moreover, noise complaints are causing significant warranty cost. This paper will focus on the noise generated only by the actuation part of the brake system, specifically the vacuum Mastervac. In this paper the noise types, their acoustic signatures in both time and frequency, as well as the current acoustic treatment impact, will be discussed with the objective of establishing a common and standardised terminology and exposing some areas that need to be looked into.