The Air Flow And Intake Port Improvement On 4112 Four Valves Diesel

With the outburst of the energy crisis in the seventies, people paid attention to the economy of the engine more and more, and the enhancement of the environmental consciousness of various countries day by day, in order to reduce the air pollution, the discharge performance of the engine obtains higher and higher attention. Four valves diesel engine obtains the widespread application because of superior dynamical performance, the efficiency and discharge performance. The main research object of the thesis is inlet port of 4112 four valves diesel intake and exhaust system, it studies the intake process in the double ports of the four valves diesel and the flow status in cylinder. The research performs the experimental study and the numerical simulation to the four valves diesel engine air intake.First according to the reverse engineering, cloud of points chart of intake model is obtained by three coordinate measurement machine, three dimensional model of the diesel engine air intake is established by means of software Pro/Engineer. As the development of computer technology, the computational fluid dynamics has become a powerful tool to the problem of fluid flow and heat transfer, it is low-cost, short cycle. Carry on stable flow three dimensional numerical computation at different valve lift with three dimensional computation hydrodynamics software AVL FIRE, obtained the detailed distribution of the pressure field, the velocity field and so on, calculate flow coefficient and swirl ratio at different lift, analyze the air stream interference on double intake ports in cross-section. Provide the important theory basis for diesel intake design and improvement.Steady flow simulation test product development and combustion engine is an important part of combustion engine product development and combustion process research. Steady flow simulation test is used to simulate actual engine intake status, evaluate the capacity of air flow of combustion engine intake and exhaust system and the form capacity of swirl ratio, it provide important test basis for the research and development on engine intake and exhaust system and for combustion process study. Carry on steady flow test with steady pressure difference, obtains the mass flow andmomentum rate. The numerical computed result and the steady flow test result of intake port are basically tallies. The result indicated that it is feasible to obtain intake port three dimensional model by means of reverse engineering method. Taking the CFD software to intake flow calculates its precision is enough.Finally, make a summary, point out some shortage, make a expectation to the next research work.