Research And Development Of Electronic Control Unit Hardware For High Pressure Common Rail System Of Diesel Engine

With the Euro Ⅳ and Euro Ⅴ gradual implementation of emission regulations, low emission, low fuel consumption and high power is the main development trend of diesel engine. It is the unique advantage in performance, fuel economy and low emissions for the electronic control system of high pressure common rail in diesel engine. It is flexibly controled for injection pressure, injection volume, injection time and injection characteristics. Hence, the electronic control unit (ECU) of high pressure common rail for diesel engine have been mainly designed and researched.The present situation and the future development trend of electronic control system for the high pressure common rail have been introduced.Combine with the high pressure common rail electronic control system of Bosch. The composition working principle and demand of electronic control unit have been analyzed. In order to the TC1728of Infineon’s32-bit car special microcontroller as the core, offer to the overall design scheme of ECU hardware.Using the overall design scheme, the design requirement and the circuit principle is detailly analyzed, and the corresponding circuit is designed. It contains microcontroller minimum system circuit, power supply circuit, communication unit circuit, outside EEPROM circuit, sensor signal processing circuit, injector solenoid valve driving circuit, fuel metering unit driving circuit, preheating plug driving circuit, relays driving circuit and H bridge driving circuit. The focus of fault diagnosis for the injector solenoid valve driving circuit is detailediy analyzed and designed. Using a method of the quickly start the engine, the engine starting operation have been tested on engine bench. The crankshaft and camshaft signal processing circuit, the injector driving circuit and the fuel metering unit driving circuit of ECU have been verificated.According to the requirements of ECU software functions and the object of study, the requirement of layout, grounding and routing for the ECU hardware PCB have been proposed. The test using ECU hardware, what the fuction of ECU hardware for the high pressure common rail diesel engine is relatively complete, have been designed and manufactured. On the unit tests for ECU hardware, the experimental results show that the signal processing circuit of sensor, the driving circuit of injection solenoid valve and fuel metering unit can meet the designing requirements. The injection current increase from OA to18A within100μs, drop12A to0less than80μs.From the rise and shut off ability, using the design of closed-loop current control for the fuel injection solenoid valve can achieve the multiple injection capacity. Furththerly, it is proved by the feasibility of design ECU hardware for the high pressure common rail in diesel engine.