Abstract
This paper presents a new prototype system capable of automated disc brake squeal suppression using a method of varying the leading and trailing piston pressures in a multi-piston opposed brake caliper. The new system consists of a novel modular four-piston brake caliper, a two-channel brake actuation system and an advanced control system that is capable of varying the leading/trailing pressure ratio (LTPR) when squeal is detected. The amended LTPR results in movement of the centre of pressure (CoP) position at the pad/disc interface, which leads to new dynamic parameters of the brake system and thereby to different squeal propensity. Moreover, the control system maintains the overall brake torque at a constant value, so the variation of the LTPR on the brake performance is minimised. Experiments using the current disc brake setup showed that by varying the LTPR, thereby changing the CoP position, the squeal occurrence can be successfully controlled. Large leading or trailing offsets typically lead to a quieter brake. Tests demonstrating operation of the proposed squeal control system in an automatic mode reduced the squeal occurrence significantly for a given duty cycle.
Highlights
Brake squeal is a relatively high frequency noise ( . 1 kHz) that frequently emerges during operation of friction brakes and is still regarded as one of the most challenging problems in the brake industry
The purpose of this paper is to present a new prototype system capable of automated disc brake squeal suppression using a method of varying the leading and trailing piston pressures in a multi-piston opposed brake caliper, while controlling an additional parameter such as brake torque
Cabin microphones that are becoming standard vehicle accessory could be used for squeal detection. It has been demonstrated via brake dynamometer experiments that variation of the leading/trailing pressure ratio (LTPR) influences the squeal frequency spectrum; some low-frequency squeals occured less frequently or disappeared completely for a specific LTPR
Summary
Brake squeal is a relatively high frequency noise ( . 1 kHz) that frequently emerges during operation of friction brakes and is still regarded as one of the most challenging problems in the brake industry. Squealing brakes are associated by most drivers with a malfunctioning system and are the subject of numerous warranty claims that account for additional costs for the car manufacturers.[2] To tackle this problem, great endeavors have been made by many researchers to understand the squeal creation mechanism and numerous theories have been proposed.[3] The majority of research in this field is aimed at finding passive measures to reduce or eliminate brake squeal. A passive approach may sound justifiable as it minimises the brake system complexity, thereby total mass and costs, but it might fail to reduce squeal if the environmental or brake system conditions change
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Schedule a callMore From: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering
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