Investigation and Mitigation of Brake Squeal Noise in Medium Commercial Vehicle

The braking systems for modern day commercial vehicles with GVWs ranging above 7.5 metric tons use the typical s-cam drum brake system, where pressurized air is the actuating medium. The s-cam drum brake systems are popular today even after the advent and penetration of air disc brake systems, the main reasons being, cost-effectiveness, robustness, satisfactory performance and good component life. However, the brake systems of commercial vehicles (both M and N category) are frequently grappled with NVH issues particularly in the form of brake squeal noise (low frequency and high frequency). The noise with frequency more than 500 Hz can be generally defined as brake squeal. There has been a lot of work done and is being continued, at theoretical level, analytical level and experimental level to tackle with this issue. But the underlying physical phenomena causing the brake squeal are quite dynamic in nature and have a probabilistic chance of occurrence, which makes it difficult to give a universal solution that can be implemented on all types of vehicles. This paper deals with the specific trials and analyses carried out on the subject vehicles-Medium Commercial Vehicle (truck) with 16 metric tons of GVW (Gross Vehicle Weight) to narrow down on the probable root causes and the subsequent actions taken to mitigate the issue to substantial levels. Also, these corrective actions were validated and proven with time bound tests carried out on the subject vehicles.