Research Of Rail Pressure Control Strategy For Light Duty Diesel Common Rail System Based On MPC5644

With the increasing environmental problems caused by vehicle emission, the more strict emission regulation the national V will be excuted soon, which means that the electronic control VE distribution pump with independent intellectual property rights has been unable to meet the demand, we must choose the high pressure common rail system for upgrading. Compared with the old injection system, the high pressure common rail system can make the injection quantity more accurately and the start of the engergising time more punctually, which will make the diesel work steadilly with smaller pollution, lower noise and oil consumption. Rail pressure control is always a difficult problem in common rail system, according to lots of documents, design the light duty diesel common rail system based on MPC5644 and study the rail pressure control strategy, so that the engine can work smoothly in all operation conditions.Firstly, study the light vehicle diesel common rail system, analyse the mechanism of its key parts, design the overall scheme of hardware and software of rail pressure control system.Secondly, according to the rail pressure control system hardware functional requirements, the hardware design is completed. The MPC5644 functions of each module are introduced; analyze the control principle of the proportional electromagnetic valve; the design of proportional electromagnetic valve drive circuit and the sampling circuit; experiments are carried out to verify the design; design the rail pressure signal acquisition and processing circuit.Thirdly, according to the rail pressure control system software functional requirements, software design is finished. Includes:engine condition judgment module, the actual rail pressure sampling and filtering module, target rail pressure calculation and correction module, the oil flow precontrol module, pressure relief compensation module based on injector, pressure wave compensation module and intelligent rail pressure control module.At last, a lot of MAPs related to rail pressure control are calibrated on the fuel pump test bench, according to the steady-state condition and transient condition of rail pressure control test, rail pressure control accuracy can meet the system requirements.