EXPERIMENTAL STUDY INDICATORS IN SMALL-DISPLACEMENT ENGINE FORCOMPACT TRACTOR

Abstract

Problem. Engine selection for a specific type of transport vehicle, configuration and refinement of mathematical models of processes, improvement of engine construction are produced based on the results of experimental researches. However, in technical literature, and even the information resources of the manufacturers it is provided very limited information about the small-displacement motors. In addition, the available data often contradict each other. Goal of the article: experimental research of fuel efficiency and toxicity of exhaust gases of the small-displacement engine Briggs & Stratton Vanguard 18HP at different loads and speeds. Methodology. The engine performance parameters were evaluated on the experimental set-up of the internal combustion engines department of National Technical University "Kharkiv Polytechnic Institute". Characteristics of the engine on the modes with speeds 1800, 2400, 3000, 3600 rpm and loads from idle to maximum were obtained. As a result of experimental data processing it were determined volumetric efficiency and air/fuel ratios. Total friction mean effective pressure was obtained by extrapolation the plot of fuel consumption versus brake output back to zero fuel consumption. Results. The impact of engine load and speed on the parameters of the fuel efficiency and emissions of the engine was analyzed. It is shown that the level of motoring losses in the small-displacement engine Briggs&Stratton Vanguard 18 HP corresponds to the motoring losses in gasoline engines with greater volume and speed. The empirical equation for determining total friction mean effective pressure in the engine was proposed. It is shown that formula proposed by V.G.Dyachenko provides satisfactory accuracy of determining total friction mean effective pressure. Originality of work consists in the proposed empirical dependence of total friction mean effective pressure from the engine speed for small-displacement engine. Рractical value consists in the parameters of the small-displacement engine at operating speeds, the assessment of the applicability of the different empirical dependencies for evaluation of the motoring losses in the small-displacement engine.