Systemic modelling and simulation approach to estimate Brake response time in a Pneumatic brake systems

Brake response time in truck air brake systems is crucial for ensuring safety and operational efficiency. This paper presents the development of a simulation model designed to meet all necessary regulatory requirements for Brake response time and as an input to the stopping distance calculations. The actual pneumatic circuit, including brake valves, relay valves, brake chambers, and plumbing have been replicated. The focus is on utilizing 1D simulations to predict the compliance of response time during both the pressurizing (brakes applied) and depressurizing (brakes released) phases of the brake system. A mathematical model is developed using a commercially available 1D simulation tool. This model employs a lumped parameter approach for the pneumatic components, with governing equations derived from compressible flow theory and empirical valve flow characteristics. A parametric study is carried out on variables such as plumbing length, system pressure, and valve orifice diameters. The simulation outcomes provide detailed response time and pressure build-up profiles. Overall, the proposed approach offers actionable insights to optimize air brake designs during the development phase, thereby, significantly reducing the need for expensive testing.