The article discusses the reasons of fatigue failure of pistons of high-loaded diesel engines. A deformation-kinetic criterion is proposed, generalized to non-isothermal loading, which allows more correct calculation of the number of thermal loading cycles before the appearance of fatigue damage. For a specific implementation of the proposed criterion, a calculated assessment of the piston stress-strain rate was carried out using the FEM. The boundary conditions for the calculation were obtained by thermometry of the piston head on a non-motorized thermal stand (TS). Comparison of the calculated and experimental values of the number of thermal cycles before the appearance of cracks on the edge of the combustion chamber (CC) of pistons made by casting and isothermal stamping is given.
The article describes the strategy of energy saving management in the field of operation of ground transport, developed on a fundamentally new basis for the effective transformation of the energy potential of waste heat energy. In the course of the work, the energy technological scheme is investigated and proposed based on the organizati on of thermochemical conversion of the initial hydrocarbon fuel using waste heat into a new type of synthesized fuel with higher rates of heat of combustion. The mechanism of this effect has not yet found its detailed consideration in the modern theory and practice of power engineering. It is based on the law of energy conservation, which in thermochemistry is interpreted as the law of Hess and its consequences.
The article presents the results of the comparative analysis and experimental approbation of efficiency of processing methods for processing certain types of alternative energy sources in a fuel for vehicle engines.
Diesel-to-natural gas engine conversion is an important economic task. In this modification the gas engine has some fundamental differences from the diesel: forced ignition is replaced by Compression ignition; as a rule, external mixture formation instead internal mixture formation; the quantitative load control using throttle - instead quality load control. The latter is one of the main reasons for the deterioration of the fuel economy of the gas engine especially at low loads, because of the significant increase in pumping losses when reducing the load by throttling. The greatest value of such losses is on the idle speed. The authors considered the possibility of increasing the efficiency of the gas modification due to the implementation of the Miller cycle, where the load reduction is achieved by variable valve timing - mainly the valve Duration and intake valve closing angle. In this case, the load reduction is achieved without the use of throttling the fuel / air mixture. The analysis is performed using a calculation method, which was developed a special program takes into account the main physical processes of the gas engine at low operating conditions. The authors considered several options for improving fuel economy at engine low load operation for the engine KAMAZ-820.74-300, including the possibility of using lean air fuel mixture, increasing the compression ratio, load management using changing valve timing. The authors defined the values of temperature and pressure at characteristic points of the pressure volume diagram, and the values of indicated thermal efficiency of an engine, fuel consumption and other parameters for the five variants of idling. The authors presented the calculated pressure volume diagrams of a Miller cycle at idle. The authors have shown the best option, where possible fuel economy improvement at idle is 25 % compared to the base engine.
The article describes the experimental plant and its equipment for studying the parameters of internal combustion engine running on gasoline-ethanol fuels. There are also given the parameters of internal combustion engine obtained with help of this experimental setup.
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