Research On Cylinder Pressure Closed Loop Control Technology Of High Pressure Common Rail Diesel Engine

With the promulgation of strict diesel emission regulations and the promotion of the concept of intelligent ships,closed-loop feedback control based on in-cylinder pressure has been widely used in marine diesel engines.However,due to the high price of a cylinder pressure sensor and the imperfection of cylinder pressure closed-loop control technology,the cylinder pressure closed-loop control technology is still in the stage of development and research.Because of the uncertainty and real-time control requirements of the real engine,the development of the cylinder pressure closed-loop control technology is still in the software and hardware in the loop simulation platform,so a complete closed-loop rapid control prototype based on in-cylinder pressure is necessary to be developed.The application of pressure closed-loop control system to the bench is an important step in the development and application of cylinder pressure closed-loop control technology.Taking a CA4DLD18E5 high pressure common rail diesel engine as the research object,a complete set of IPCCRP（In cylinder Pressure Close-loop Control Rapid Prototype）was developed in this thesis.IPCCRP includes BCRP（a Base Control Rapid Prototype）and CCRP（a Closed-loop Control Rapid Prototype）.Both of them are based on MPC5634 hardware platform of Freescale and model-based software development mode.BCRP mainly realizes the control of starting,running and stopping of diesel engine,while CCRP triggers the acquisition of cylinder pressure signals of diesel engine in real time according to crankshaft and upper dead-end signal.With combustion characteristic parameters IMEP and CA50 as feedback variables,the correction values of injection timing and injection pulse width of each cylinder are obtained and transmitted to BCRP through CAN bus,in order to realize the separate control of fuel injection in each cylinder of diesel engine and achieve the purpose of closed-loop control of cylinder pressure.Integrating BCRP and CRP,IPCCRP is applied to a small diesel engine bench in the laboratory.Whether the cylinder pressure closed-loop control system can collect the cylinder pressure data normally,whether the correction values of injection pulse width and timing of each cylinder and whether the closed-loop control system of cylinder pressure can meet the real-time requirements of the control are obtained according to the collected cylinder pressure data,those are validated.The results of the bench test show that the closed-loop control system of cylinder pressure can meet the requirements of closed-loop control of cylinder pressure and reduce the unevenness of each cylinder.The main research work of this thesis is the design of BCRP and CCRP of diesel engine in cylinder pressure closed-loop control system,and the integration and debugging of the two rapid prototypes,which are applied to the diesel engine bench in the laboratory to verify the engine.The research results provide a development platform and reference for the optimization and calibration of cylinder pressure closed-loop control system in the next step.It can promote the application of cylinder pressure closed-loop technology in marine diesel engine.