Disc and Drum Brake Dynamometer Squeal Noise Test Procedure for Air-Braked Vehicles
This RP applies to on-highway vehicles over 4536 kg (10000 lb) GVWR. This RP is intended to characterize the squeal propensity and behavior of the friction couple, without the influence of the complete wheel-end or vehicle.
Rationale: The market expectation for commercial vehicles is to provide quieter operating vehicles. Commercial Vehicle brake induced noise can contribute to objectionable higher frequency noise, typically referred to as ?brake Squeal, the public, in general, is more sensitive to vehicle noise, vehicles overall are becoming quieter, and development cycles for new friction couples are getting shorter. Brake squeal noise is becoming part of systematic product screening and gaining overall importance, which needs the attention of the brake system and friction material suppliers. This Recommended Practice (RP) aims at providing a laboratory brake squeal matrix using the basic structure of the SAE J2521. The SAE J2521 has been a valuable tool for the automotive industry to characterize squeal noise by replicating conditions that may induce noise on a given brake assembly. This RP indicates the minimum requirements for the brake setup, the inertia dynamometer capabilities, the test sequences, and the test report elements.