Auto Testing of FCPV and ADC Joint AirLeak Detection Using PLC

Abstract

Most vehicles involved in accidents now a days are the big vehicles like lorries, buses and trailers. Their braking system is quite different from the small cars. They have air tank for their braking system and hence the amount of air required is tremendous. Air braking system uses air as a way of transmitting pressure from the drivers control to the service brake. This compressed air has some water which cannot be compressed. The more water in the tank the less the compressed air volume is. Whenever the foot brake is applied, large amount of air is used. If the air pressure does not build up fast the pressure may drop to low if leak is present in the system which affect the efficiency of entire braking system of vehicles. A leak can be defined as an intended crack, hole or porosity in an joint which must be excluded from the system. A leak test procedure is usually a quality control step to assure device integrity and should preferably be a onetime non-destructive test, without impact on environment and operators. The three basic functions of leak testing are leakage detection and its location, measurement of leak rate.One of the test presently used in industry is soap solution bubble test. The pressurized unit to be tested is sprayed with a soap solution and the operator is able to see the bubbles formed by gas escaping from where the leak is, the more the bubbles the larger is the leakage .If the part is not simple and easily accessible it is difficult for operator to perform above mentioned test, also the test is time consuming, affecting the efficiency, accuracy and productivity of system. To overcome the disadvantages of the above mentioned system we are implementing pressure decay test using PLC which would determine air leakage between ADC(Air Dryer cartridge) and FCPV(Four Circuit Protection Valve) joint to improve the braking efficiency of vehicle system.