Mathematical model of dynamic processes during operation of the control cock of car parking brake system

A mathematical model of dynamic processes of functioning of the control cock of car parking brake system — one of the important and responsible control apparatuses of the air brake control of modern cars — is developed. This mathematical model of the apparatus includes equations of dynamic equilibrium of its moving elements, as well as differential equations of gas-dynamic processes occurring in the control cock of car parking brake system during its operation. The equations of gas-dynamic processes in the model are made on the basis of hyperbolic functions of gas flow rate in the system 'capacity — adjustable restriction' taking into account the dynamics of opening and closing of valves of the parking brake system control in the process of its operation during braking and unbraking of the car. A distinctive feature of the mathematical model is that it describes the processes in the air brake control apparatus, which functions on the basis of 'reverse logic', i.e. braking occurs at the release of the working body from the executive apparatuses of the pneumatic brake drive, and releasing — in the process of their filling. The obtained results of calculations of dynamic processes of the parking brake control cock functioning in the form of temporal, as well as in the form of phase dynamic characteristics are in good agreement with the results obtained in the process of its experimental studies on the computer complex IRNRTU. The developed mathematical model allows to obtain and study phase dynamic characteristics of the parking brake control cock by calculation methods. It allows designers-developers of air brake drive apparatuses to optimise the design of apparatuses with reverse logic, taking into account the variation of its geometric, kinematic and power parameters, and specialists in the field of operation to develop methods of non-destructive control of parameters of their technical condition.