Marine High Pressure Common Rail Diesel Common Rail System Modeling And Simulation

High-pressure common rail diesel engine as the most potential for development of diesel engines, it can not only control the diesel engine injection and exhaust timing exactly, but also enables the establishment of injection pressure and engine speed completely separate from each other, which ensures the diesel engine in any load can obtain a higher injection pressure. To adapt to the global energy-saving and emission reduction requirements, it can reduce emissions under the premise of ensuring diesel power. Currently, institutes, universities and large diesel engine manufacturers have more researched and developed vehicle diesel engine in-depth, but the study of large marine low-speed high pressure common rail diesel engine is still in infancy.Comparing the status of the car and large marine low-speed high-pressure common rail diesel engine, I have chosen Wartsila production of large marine low-speed two-stroke high-pressure common-rail diesel engine7RT-flex60C as the research object. Firstly, introduce the main composition and working principle of the fuel common rail system, servo oil common rail system, control oil common rail system and the WECS-9500control system. Secondly, with the idea of modular modeling based on the fluid mechanics continuity equation, the motion equations and control logic, establish physical and mathematical models of fuel common rail and servo oil common rail systems. Fully consider the impact of pressure changes on the fuel density, elastic modulus, and kinematic viscosity in modeling of the fuel common rail system. Finally, use numerical calculation to calculate the model, analyze the difficulties of using the method of feature line and choose the empirical formula method to solve the mathematical model.Using MATLAB/Simulink to establish a simulation model of common rail system. Simulating the cam lift and plunger chamber pressure of high-pressure pump, the pressure and flow of intermediate fuel accumulator and fuel rail, the flow control piston front cavity pressure and piston movement of ICU, the movement of injector needle, the piston displacement and cavity pressure of servo pump, the pressure of collector and servo oil common rail pressure, the piston upper cavity pressure and the piston movement of VCU. the movement of exhaust valve. Comparing the simulation fuel injection quantity and that of the experimentally measured number, verifies the correctness of the simulation model. Obtaining some conclusions by comparing different parameters on system performance. Providing reference and guidance for domestic R&D on large marine low-speed two-stroke engine of high-pressure common rail system.