COMBINATORY APPROACH TO FAILURE FINDING IN PASSENGER CAR ELECTRICAL EQUIPMENT SYSTEM

Maintaining a high level of maintenance of electrical equipment in passenger cars requires research in the field of improving methods and means of technical diagnostics. Electronic devices for automatic control and protection, which are located in the switchboard of the car, are one of the most critical elements in the electrical equipment system, ensuring its reliable, efficient and safe operation. If the automatic adjustment and protection devices are out of regulation during operation, the voltage and current in the electrical equipment network may exceed the permissible level, which leads to the failure of electricity consumers, a battery and a generator. In addition, the semiconductor devices themselves are very sensitive to short-term overloads, in which, even with minor overloads, a breakdown or breakage of the conductive layer occurs. Modern trends in the development of passenger car fleet indicate a sharp increase in the complexity of the element base of cars. This mainly concerns the electrical systems of cars, where all the functions of control, monitoring and diagnostics are performed by electronics. Maintaining a high level of service for such systems requires research in the field of improving methods and means of technical diagnostics. For these purposes, the authors have developed a method for constructing optimal control and diagnostic tests, which is based on a combinatorial approach. The method is easily implemented on a computer.

THE CONCEPT OF THE PASSENGER CAR LIFE CYCLE

The article deals with the issues of a conceptual approach to determining the life cycle of a passenger car. The fleet of passenger car mainly consists of models developed and manufactured in the 70-90s of the last century at car plants in Germany and Russia. They are obsolete both morally and physically. This necessitates the renewal of the passenger car fleet by purchasing cars of both domestic and foreign production. In modern conditions, the user of new technology is interested not only in the purchase price, but also in the after-sales costs. This is reflected in the life cycle cost. It is proposed to use a cascade life cycle model for a passenger car. The stages of the life cycle of a passenger car during operation on the railways of Ukraine have been determined. The components of each stage of the life cycle of a passenger car are considered. For a transport company that intends to operate a passenger car, the costs of the first three stages are directly expressed in the initial cost of the car - the purchase price. The life cycle cost (LCC) of a passenger car will be determined by summing up the individual outflow of funds (expenses) at each specific stage (calculation step) of the service life of the equipment. The life cycle assessment of the technical system of railway transport can work at any stage of the life cycle.

PRINCIPLES OF CONSTRUCTION OF THE GENERALIZED MATHEMATICAL MODEL OF THE HYDRAULIC EXTINGUISHER OF OSCILLATIONS OF THE PASSENGER CAR

The study of the processes associated with the use of working fluids in the elements of hydraulic drives was preceded by studies of the unsteady periodic movement of the working fluid in the pipelines of hydraulic systems. Such processes take place in hydraulic drives and their elements, and are associated with the compressibility of the working fluid. The stability of the operation of hydraulic valves, which are supplied to hydraulic systems in order to maintain, within the required limits, pressures or flow rates, is also largely predetermined by non-stationary hydro mechanical processes occurring in the pipelines of these systems, channels and chambers of hydraulic devices. The peculiarities of the working processes of passive vibration dampers of passenger cars include the interaction of the working fluid with moving parts and its flow through the channels and through the calibrated holes with local artificial resistance. For in-depth analysis of changes in operating parameters, it is necessary to use a mathematical model that should reflect the processes that occur during the operation of the hydraulic device. In the presented article the generalized mathematical model of the hydraulic damper of fluctuations of the passenger car of the НЦ-1100 type is developed. This model takes into account the special operating conditions of the hydraulic shock absorber, which allows you to study the impact of operating parameters on the performance of the device.