Experimental And Simulation Study On The Performance Of Ji Chai 260 Diesel

In this thesis,the economical efficiency,emission characteristics and stable combustion are studied using the 260 diesel designed by Ji Chai by the combined method of experiment and simulation.The main research contents are as follows:Firstly,five groups' experiments of advanced characteristics are complicated.Then the curve of advanced characteristics and the pressure curve of first cylinder with the speed of speed 795 r/min and 1000 r/min are proposed respectively in consideration of the relevant performance parameters.Also,the results are used to build and validate the 260 whole model that is studied later.Secondly,the whole model of 260 diesel,including the intake and exhaust system,turbo system,spray combustion system et al,is established using a commercial software named GT-Power.The combustion model is validated in accordance with the experimental results of the cylinder pressure curve,which proves the accuracy of the combustion model.Moreover,the performance parameters of experiment like the specific fuel consumption and indicated mean effective pressure are compared with the calculation results.The maximum deviation is within 5%,which proves the accuracy of the whole model.Thirdly,the effects of fuel inject-timing and timing of exhaust valve open & intake valve close(EVO&IVC-timing)on the performance of economy,emission and stable combustion of 260 diesel are researched using the whole model.A better fueling inject-timing and EVO&IVC-timing for every conditions of advance experiment are found.The result shows,the brake specific fuel consumption(BSFC)and the maximum rate of pressure rise of 260 diesel are decreased,except the BSFC of the condition with speed 630 r/min.Finally,the effects of EGR(Exhaust Gas Recirculation)rate on the performance of 260 diesel are discussed using the 260 whole model with EGR system.The better EGR rates are selected to every conditions,which not only reduce the NOx emissions significantly,but also have little influence on the other performance parameters.Wherein,NOx emissions with the speed of 630 r/min are reduced by about 16%,while NOx emissions of the other four conditions are reduced by 30% to 40%.