Hardware In The Loop Simulation System Study Of High Pressure Common Rail Diesel Engine

Nowadays, the technology of diesel engine is developed quickly in order to reduce fuel consumption and vehicle emissions. With the functions, complexity and control precision of engine electrical system (ECU) constantly increasing, the corresponding difficulty in development progress is also enhancing. So in research and development period of ECU of diesel engine, the engineers need tools to test and verify the reliability of new control strategies implemented in the ECU. Therefore the optimal solution is the operation of the ECU test in a real time closed loop environment, commonly named hardware in the loop simulation system (HILSS), which lead the develop work simply and agility.The high pressure common rail diesel engine is a bran-new technology. During developing electronic control system of the new kind of diesel engine, the simulation research work of every work conditions must be more accuracy and the diesel dynamic model must be characteristic of HILS. The study of diesel engine HILSS is carried on including as following:1. The simulation model presented in this paper is a combination of mean value model and"filling and emptying"model as HILS model, which model overcomes the limitation of other model, such as depend on test data, bad universal and few control parameters. The model ensures real time demand and improves the universal. At the same time,"filling and emptying"model makes the diesel engine emission prediction possible.2. The turbocharged diesel engine model and common rail fuel supply system model are established by Matlab/Simulink developing tools. Then intelligent"Genetic Algorithm"is used to optimize the simulation step, in order to obtain the best real time character and preciseness. After verified the diesel engine model by steady data including calculation result and test results, the typical engine dynamic conditions are simulated. Simulating parameters change according with the actual situation during the whole simulation process. It is helpful to the electrically controlled turbocharged diesel engine control strategy verification and the control parameters adjustment.3. Neural network is applied into simulation widely for its merit of strong nonlinear mapping. A NO_x emission model based on neural network can be trained to reflect the complex relationship between the amount of NO_x and some direct influence factors. Combined with dynamic engine model of"filling and emptying"method, NN model can reach the trade-off between simulation accuracy and computational overhead. After amending, the NN model even can predict NO_x emission during the transient performance of diesel engine in a certain extent.4. In order to simulation complex vehicle engine driving performance dynamic loads characteristic, a real time simulation mode is found based on automobile driving force and resistance balance equation. The model is validated by vehicle test data.5. A new rapid developing method has been introduced in this dissertation. The diesel engine and fuel supply system model chart is constructed in Matlab/Simulink modeling and simulating environment. The models could be generated to be optimized, portable, and customizable code from Simulink models by Real Time Workshop (RTW). So the customer's real time model is executed in terminal with real time kernel. So in comparison with traditional method, the new method accelerates the development of the HILS.6. A simulation platform has been designed in this dissertation which includes RTAI real time OS and I/O interface. The simulated system could convert diesel engine performance parameters and input and output signal, and provide the interface of ECU. This platform could satisfy the high demand of diesel engine HILSS with open mode character.7. Research of control strategy and ECU rapid prototype carried out for high pressure common rail diesel engine. After comparing several kinds of control strategies, A PID controller with parameters fuzzy adjusting itself is designed, which is with higher control accuracy and reliability. At last the ECU rapid prototype developed through RTW, which includesμC/OSII embed real time OS and ARM processor, avoiding fussy programming and debug process.A complete HILSS is established in this paper with real time and universal character, which is a useful tool to develop diesel engine ECU.