Study On Diesel Engine Combustion Control Based On Model Prediction

With the increase of emission standards and the increasing demand for energy saving,it is difficult to meet the development needs for fuzzy control of fuel injection using traditional control methods,which puts forward higher and higher requirements for the real-time nature of combustion control of internal combustion engines.Therefore,it has become an urgent need to study how to accurately and real-time control the combustion process of diesel engines.The combustion control can be achieved by controlling the fuel injection process of the diesel engine,which requires a more accurate fuel injection system control strategy.Therefore,using a control strategy based on model prediction to establish a diesel engine fuel injection control system can shorten the control cycle and achieve the purpose of real-time and accurate combustion control.The main purpose of this paper is to develop a diesel engine combustion control system based on model prediction and to verify it.The Weber equation is used to establish the combustion process control model,the combustion control strategy is developed based on the MFB50,the real-time control system hardware design and software development are carried out according to the combustion process control strategy,the CAN bus is used to realize the control system communication,and the CCP communication protocol is used to realize the control system and ECU side.Data interaction,through the real-time modification of the fuel injection strategy,realizes the control of the combustion process.Finally,a control system was installed on the diesel engine test bench for testing and verification.(1)First,the calculation of the working process of the diesel engine is carried out.The purpose is to analyze the parameters of the prototype TBD620 high-pressure common rail single-cylinder diesel engine,calculate the working process parameters of the diesel engine,determine the intermediate function relationship and theoretically solve the various parameters of the cylinder working process.Then,according to the experimental data,the required parameters in the Weber equation are calculated,and then the parameter values needed to establish the Weber equation are obtained,and the simulation model is established.According to the control theory model,a control module that can operate in conjunction with the simulation model is established,and the control model is simulated through joint simulation.The results show that the simulation control module can control fuel injection in real time.(2)In terms of hardware design,it is designed according to the control strategy.The minimum circuit control system and can bus communication module are designed according to the requirements of model-based real-time operation and can bus communication.The rest of the hardware design has completed the OLED screen module design,USART communication serial port module design,touch key module and other related hardware circuit design,and then completed the hardware design of the control system.(3)In the case of determining the software function module,adopt modular design to obtain multiple software function modules,such as initialization module,CAN communication module,CCP communication module,system logic connection establishment and disconnection module,model control program,data acquisition and calibration program After the module waits,carry on the static experiment test control function to the procedure.(4)The experiment is carried out on TBD620 high pressure common rail single cylinder diesel engine test bench.The real-time control strategy based on model prediction is verified,and the control system is preliminarily tested.The real-time control system is used to control the injection advance angle of diesel engine based on the model,which affects the combustion of diesel engine.The operation status of TBD620 single cylinder diesel engine is compared with that of the original engine and after the control system is installed.The results show that the control system operates normally and the error between experiment and calculation CA50 is s less than 0.3.The speed fluctuation is within 20 R / min.The control strategy based on model prediction can make the diesel engine run more stable.Through the hardware design and control system software development of this system,the development and experimental verification of the control system are realized,which lays the foundation for the engineering of the real-time control system of marine high-speed diesel engines.