Purpose. The existing mathematical models of unsteady heat processes in a passenger car do not fully reflect the thermal processes, occurring in the car wits a heating system. In addition, unsteady heat processes are often studied in steady regime, when the heat fluxes and the parameters of the thermal circuit are constant and do not depend on time. In connection with the emergence of more effective technical solutions to the life support system there is a need for creating a new mathematical apparatus, which would allow taking into account these features and their influence on the course of unsteady heat processes throughout the travel time. The purpose of this work is to create a mathematical model of the heat regime of a passenger car with a heating system that takes into account the unsteady heat processes. Methodology. To achieve this task the author composed a system of differential equations, describing unsteady heat processes during the heating of a passenger car. For the solution of the composed system of equations, the author used the method of elementary balances. Findings. The paper presents the developed numerical algorithm and computer program for simulation of transitional heat processes in a locomotive traction passenger car, which allows taking into account the various constructive solutions of the life support system of passenger cars and to simulate unsteady heat processes at any stage of the trip. Originality. For the first time the author developed a mathematical model of heat processes in a car with a heating system, that unlike existing models, allows to investigate the unsteady heat engineering performance in the cabin of the car under different operating conditions and compare the work of various life support systems from the point of view their constructive solutions. Practical value. The work presented the developed mathematical model of the unsteady heat regime of the passenger car with a heating system to estimate the efficiency of unsteady, transitional temperature states in passenger cars, taking into account the design features of the heating system and the regulatory requirements. This allows the development and implementation of optimal technical characteristics of heating appliances and the construction of an algorithm for controlling their operation in accordance with operating conditions, taking into account the thermal inertia of the car in the transitional modes of heating, on the basis of mathematical modeling.

Passenger rolling stock is an important component of passenger transportation services, which should ensure not only traffic safety, but also comfortable transportation conditions. Studies on the energy saving of railway rolling stock have revealed shortcomings in the operating documentation that increase the unproductive consumption of thermal energy by passenger cars during the operation of a heating system with a combined electric-coal boiler in electric heating mode. Experimental measurements confirmed the presence of unproductive losses of thermal energy through the intake blinds of the ventilation system due to the infiltration of outside air during downtime at the points of formation and turnover of passenger cars. Also, experimental measurements showed that there is a leak of warm air through the deflectors to remove exhaust air from the car into the environment. This is their regular mode of operation, but as highlighted in the author's early publications there are two zones of temperature fields in the body of the passenger car with different temperature regimes, which are separated by a decorative ceiling. The results show that the leakage of warm air through the deflectors occurs from the temperature field zone with a higher temperature, which increases the unproductive consumption of thermal energy. Thus, by making appropriate changes to the operating documentation based on the study, the energy efficiency of passenger rolling stock will be greatly improved in its further operation. In particular, it is established that the proposed modernization in order to increase the energy efficiency of the heating system can be carried out at relatively low cost, in modern car repair depots during overhauls, and also needs to be considered when designing new passenger cars.

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Досліджено способи поліпшення техніко-економічних параметрів систем життєзабезпечення рухомого складу. Встановлено, що при проектуванні пасажирських вагонів конструкторами не враховується низка чинників, які впливають на енергоефективність систем життєзабезпечення пасажирських вагонів. Визначено шляхи підвищення енергоефективності систем опалення пасажирських вагонів. Проведене

Purpose. The research paper proposes to estimate the effect of heat inertia of the water heating system, in transient operation modes, on the temperature condition in the passenger car, as well as to offer technical solutions intended to reduce the heating system inertia effect and to maintain a stable temperature condition in the passenger car premises in transitional modes of the heating system. Methodology. The author developed the method for controlling the heat transfer of heating system pipes with the help of regulating casing. To control the heating system and the heat transfer of heating pipes, two types of temperature control sensors were used in the passenger car: certain sensors interacted with regulatory casings, while the others interacted with high-voltage tubular heating element control devices. To assess the efficiency of heat interchange regulation of heating pipes and the heating system control, with installed regulating casings, the operation of the heating system with regulating casings and two types of sensors was mathematically modelled. Mathematical modelling used the experimental test data. The results of experimental tests and mathematical modelling were compared. Findings. Currently in operated passenger cars, control of heating appliances is not constructively provided. Automatic maintenance of the set temperature in a passenger car is limited to switching on and off of high-voltage tubular heating elements. The use of regulating casings on heating pipes allows reducing the effects of heat inertia and maintaining stable thermal conditions in a passenger car, using the heating system as a heat accumulator, and also provides the opportunity to realize an individual control of air temperature in the compartment. Originality. For the first time, the paper studied the alternative ways of regulating the temperature condition in a passenger car. Using of the heating system as a heat accumulator. Practical value. The regulation of the heat transfers of the heating pipes by regulating casings allows reducing the effect of thermal inertia of the heating system on the temperature condition in a passenger car, implementing individual adjustment of air temperature in a compartment within 40% of the power of the heating pipe section, using the heating system as a heat accumulator.