Development and Modelling of an Electropneumatic Brake System for Commercial Vehicles

 

The brake system is the primary safety system in an automobile which ensures its safety on the road. The ideal brake system should operate with the least effort from the driver and should stop the vehicle within the minimum possible distance. The research work presented in this thesis deals with the air brake system which is widely used in commercial vehicles such as trucks, buses and tractor-trailers. One of the important parameters which affect the stopping distance of a vehicle is the brake response time. The brake response time for the conventional air brake system is comparatively higher than the brake response time of the conventional hydraulic brake system which is used in passenger cars. Hence, if the speed of response of the air brake system is increased, it will lead to improved safety of commercial vehicles on the road. This thesis focuses on the development of an electropneumatic brake which would decrease the response time of the air brake system thereby providing a reduced stopping distance.

 

Model based analysis of dynamic systems will provide valuable insights into their performance. In this regard, a mathematical model that correlates the pressure transients in the brake chamber to the voltage input provided to the electropneumatic brake has been developed. The efficacy of this model was tested by comparing its results with experimental data obtained from various test runs. It is found that the pressure transients predicted by the model agree well with the experimental data. The model is inherently able to predict the brake response for all input voltages and for all supply pressures. From the experimental results it has been found that there is a drastic reduction in brake response time in an electropneumatic brake system when compared to the conventional air brake system. This will lead to a reduction in the stopping distance of a commercial vehicle equipped with an electropneumatic brake when compared with a vehicle equipped with a conventional air brake system.