Research Of High Pressure Common Rail Diesel Engine’s Injection Pressure Control Strategy

Energy depletion is the common problem the world is facing in the 21st, the short of oil resource and high price urges us to lower the fossil energy’s consumption. The High-pressure common-rail diesel engine with high compress ratio and clean emission, due to the obvious potential in pollution and energy economy, rapidly becoming the focus of research in the world.Accurate injection quantity and timing are the center of the electrical control system. In a high-pressure common-rail system, due to the quantity are determined by fuel pressure and duration, in order to realize the advantages of the electrical engine system, keep the pressure stable is quite important.This thesis is based on a six cylinders, high pressure common-rail diesel engine, designing injection pressure control strategy, calculating the injection pressure setpoint and control mode by diesel engine’s work situation, Building fuel system model to verify the control strategy. In the end, the experiment indicates that the strategy can effectly control the rail pressure, and satisify the diesel engines’work requirement. The main work of this thesis is:1. Investigating the common-rail diesel engines technology in the world, and familiar with denso’s ECD-U2 high pressure common-rail system.2. Comparing the advantages and disadvantages of embedded operation system. Migration uCOS to NEC V850ES platform, and extended its task support number, setting tasks’priorites number.3. According to the system requirement of normal and abnormal situation, finishing the injection control strategy by Matlab/Simulink, including injection pressure set, control mode transfer, fault detecting and interface and so on.4. Comparing the PID and fuzzy control strategy. Considering the chatacters of modern diesel engines, combining the PID and fuzzy control, designing a fuzzy-PI complex control method.5. Relaying on ECD-U2 fuel system, building a fuel system model. Finishing software-in-loop simulation experiment, verified the control strategy.6. Participating in the cell test, verified the strategy in the pump bench. In addition, we generating the C code from Matlab/Simulink by Targetlink, and further edit it. In the hardware-in-loop experiment, the pressure is steady at constant condition and meets the need of changing condition. In the pump bench test, the pressure has a rapid response, small overshoot and error, which can satisfy the diesel engines’need.