Research Of The Improvement Of A Small Gasoline Engine Based On Cfd

In the internal combustion engine, the cooperation of the intake system and the shape of combustion chamber has a significant on the intake charge,the mixture formation and the combustion process, so it is important to design of the intake system and the combustion chamber in the engine. The calculation of the flow system in the internal combustion engine has developed uncommonly with the development of computational fluid dynamics (CFD),computer technology and the other related disciplines .CFD is an effective means in the process of engine research and design , because it can provide more information than experiment. It can also identify the key control variables out of the many factors more easily, so it benefits to reduce the cycle and the cost in the research and design of the engine.First of all , This paper improved its intake system based on the research of relevant literature both domestic and abroad, as well as referenced to the experiences of others. and then set up the three dimensional models and conducted the three dimensional numerical simulation to the engine using the UG and AVL FIRE software whose intake system has improved. In order to make the intake tumble better, the piston top shape was also changed on the foundation of the previous simulation.The experiment of the engine intake system which has been improved was done in order to measure the inlet flow under the different valve lift . At the same time, the comparison with the simulation value was carried . And the result showed that the flow coefficients coincide with each other in different valve lift , which proved the correctness of the three dimensional numerical simulation. The simulation of the engine which was improved was also done so as to comprehend the details of the spatial distribution flow in the intake and compression processes and theirs changes with crank-angle , focusing on analysis of the changes of the law of evolution and the flow characteristics in the"Inlet-Valve-Cylinder"flow field through improving. Simultaneously, in order to understand the differences on the torque and fuel consumption between the improved engine and the previous engine, the experiments on the two engines were done too.