MODELLING OF THE ENERGY SUPPLY EQUIPMENT OF THE AIR BRAKING SYSTEM OF A FARM TRACTOR

Farm tractors are provided with pneumatic systems to control and operate air braking systems as well as pneumatic suspension systems, the latter being increasingly often applied to high-capacity trailers. The excessive consumption of compressed air may adversely affect the braking effectiveness of a tractor-trailer unit; therefore, the impact of performance of the air supply equipment of the tractor on the transient processes taking place in the air braking system of the trailer should be taken into consideration as early as at the design stage. A mathematical model of the air supply equipment, consisting of functional and structural models of individual equipment components such as compressor, pressure regulator, and compressed air reservoir, has been presented in this paper. An example has been included, where the computer model of the supply system, prepared in the Matlab-Simulink program, was used to assess the correctness of compressor selection to the pneumatic system of the Pronar 5110 tractor. The adequacy of the implemented computer model of the air supply equipment, experimentally confirmed, was evaluated with statistical methods, with the use of the Kolmogorov-Smirnov test. The computer model developed may be used as a tool to assess the correctness of selection of parameters of the air supply equipment within the designing process and as a subsystem in order to evaluate, with the use of simulation methods, the transient processes taking place in the air braking systems of agricultural vehicles