Modeling the pneumatic subsystem of a s-cam air brake system

Abstract

The air brake system is one of the critical components in ensuring the safe operation of any commercial vehicle. This work is directed towards the development of a fault-free model of the pneumatic subsystem of the air brake system. This model can be used in brake control and diagnostic applications. Current enforcement inspections are done manually and hence are time consuming and subjective. The long-term objective is to develop a model-based, performance-based diagnostic system that will automate enforcement inspections and help in monitoring the condition of the air brake system. Such a diagnostic system can update the driver on the performance of the brake system during travel and with recent advancements in communication technology, this information can be remotely transferred to the brake inspection teams. Since this system is performance-based, it will eliminate the subjective nature of visual inspections. The first step in the development of such a diagnostic system is to obtain a fault-free model of the air brake system. The model of the pneumatic subsystem correlates the pressure transients in the brake chamber with the brake pedal actuation force and the brake valve plunger displacement. An experimental test bench was set up at Texas A&M University and the experimental data is used to corroborate the results obtained from the model.

A Diagnostic System for Air Brakes in Commercial Vehicles

“…Motivated by these issues, preliminary model-based diagnostic schemes have been developed that detect leaks and push rod out-of-adjustment in a reliable manner. An experimentally corroborated "fault-free" model that predicts the pressure transients in the brake chamber of the air brake system has been developed and reported in [23].…”

“…It has been found out from experiments that observing the pressure transients in the brake chambers of the air brake system during the brake application process will help in monitoring the brake system for leaks and out-of-adjustment. Hence, a model for predicting the pressure transients in a brake chamber of the air brake system has been developed and presented in [23]. This model correlates the pressure in the brake chamber with the treadle valve plunger displacement and the supply pressure to the treadle valve.…”

“…The model presented in [23] takes into account the mechanics of operation of the treadle valve and the flow of air in the brake system. A lumped parameter approach has been adopted to model the pneumatic subsystem of the air brake system.…”

Design of on-Off Type Solenoid Valve for Electropneumatic Brake Systems and Investigation of Its Static Characteristics

“…Braking function can be achieved by mechanical, hydraulic, pneumatic or electrical systems. Most of tractor trailers with a gross vehicle weight rating (GVWR) over 19000 lb (about 85 kN), most of trucks with GVWR over 31000 lb (about 138 kN), most of transit and intercity buses and about half of school buses are equipped with pneumatic brake systems [1]. Pneumatic systems use compressed air to operate the brakes.…”

Modeling and Simulation Vehicle Air Brake System

“…The mathematic model for dynamic responses of air brake system is very complicated since many differential equations need to be solved and many parameters may be correlated with each other, especially the parameters for the key components, such as brake valve, relay valve and pipelines. A non-linear model of the pneumatic subsystem of the air brake system which relates the pressure in the brake chamber to the brake valve plunger displacement and the supply pressure to the brake valve has been developed in [5,6]. The mathematic model is very complicated, which leads it hard to be solved.…”