The Modeling And Simulation Research On Fuel Injection System Of TY3100 Diesel Engine

The fuel injection system (FIS) is the heart of a diesel engine, which affects the performance of power, economic and exhaust of an engine. Simulating calculation on FIS of diesel engine with low calculation cost, short development cycle, accurate calculation results and many other advantages has become an important method to study, design, improve and analyse FIS.By means of GT-FUEL software, this thesis firstly established the numerical model on Pump-Line-Nozzle(PLN) fuel injection system of TY3100 diesel engine on the basis of one-dimensional unstable compressible flow theory. The model include the physical model and calculation model and its parameter input. Then we carried out the numerical simulation, and the simulation shows the highest injection pressure is 650bar which is very close to the actual value of TY3100 diesel engine. The injected fuel quantity is 34.62mg which is slightly higher than theoretical value 33.40mg. The needle opens quickly, and there is no secondary injection, but have jitter phenomenon in the final phase of the injection.In addition, the detailed comparative analysis was made to such key factors as quantity of injection holes, diameter of injection hole, diameter of fuel injection pipe, length of fuel injection pipe, diameter of pump plunger. The results show that increasing pump plunger diameter or decreasing fuel injection pipe diameter can improve injection pressure and increase injected fuel quantity. Reducing spray orifice area can improve injection pressure, but reduce injected fuel quantity. With the reducing of the length of fuel injection pipe, the injection pressure was increased and that the beginning and end of injection was advanced. Too large or small FIS parameters of TY3100 diesel engine would seriously affect the performance of FIS.Finally, on the basis of the simulation and comparative analysis above, this thesis proposed an improvement scheme for FIS of TY3100 diesel engine. The highest injection pressure of improved FIS reached 750bar, which is nearly 19.2% higher than the original FIS. In addition, the jitter phenomenon in the final phase of the injection were significantly weakened and found no secondary injection. Therefore, the goal of optimizing TY3100 diesel engine FIS has been achieved.