Study On High Pressure Common Rail Diesel Engine Position Dynchronous

In order to reduce energy consumption and diesel engine emissions to meet the requirements of energy conservation and emissions regulations, the diesel engine control technology has become a developing direction with electronic technology, computer technology. ECU (Electronic Control Unit) is the brain of a diesel engine electronic control system, the location synchronization is one of its main functions. Therefore, to study the synchronization method has important practical significance.Location synchronization is the process that the ECU processes speed signal, and determines the current working the number of cylinder and the current location of crankshaft. Position synchronization is the foundation of the work of the electronic control unit normally. ECU must determine the current working number of cylinder and the current location of crankshaft to make sure that it is at the right time to make fuel inject into the cylinder correctly. According to this principle, it is researched and designed a synchronization scheme in the paper. The signal of crankshaft sensor and the signal of camshaft sensor are sent into the hardware circuitry to shape, filter, compare, and then sent them to the HET(High-end Timer). The HET measures the time of crankshaft teeth, then analyses the correctness of the signal. The front-teeth time and the back-teeth time of the crankshaft are compared to find the missing teeth by gradient. At the same time, according to HET camshaft signal information obtain by the Segment table determine timing synchronization.To alculate the speed of crankshaft, angle synchronous after completing position synchronization to make sure the correct location of fuel injection.Setting crankshaft speed and rail pressure were 800r/min,50MPa; 1000r/min,70MPa; 1200r/min,90MPa, respectively in the experimental stage of injection, then the experiment was carried on many times to make sure location synchronization. The results showed that the program was correct, and the system operated normally. Then to control the rail pressure was 50MPa on the engine stage, respectively, in the idle (800r/min), deceleration time (maximum speed for the 2000r/min) synchronization method had been repeatedly verified to ensure the realization of the right injection.The designed scheme can achieve the correct fuel injection in different conditions, location synchronization control has achieved the desired results. It has high practical value.