This project developed a prototype system to automatically detect leaks in air brakes in trucks. This is an on-board diagnostic system. It estimates the push rod stroke, in real-time, from measurements of pressure in the brake chambers and supply reservoirs.
A leak in the air brake system is detected by making “full”' brake applications (i.e. a brake application where the steady state pressure in the brake chamber is nearly equal to the supply pressure) and comparing the steady state pressure measurements in the brake chambers with the supply pressure. The presence of a leak in the air brake system and the push rod stroke being greater than the re-adjustment limit increases the lag in the response of the system to a pedal input by the driver, thus making the brake system response more ``sluggish''. These factors also lead to a decrease in the torque available for braking. A leak also increase the work load on the compressor and related components, thus leading to faster wear if undetected.
A prototype diagnostic system was developed in this project for use by truck fleet owners to perform regular maintenance inspections and by road-side inspection teams, as a fast and reliable tool in their enforcement inspections.
