Study On Some Key Problems Relevant To High Pressure Common Rail Fuel Injection System For Certain-Model Diesel Engines

Common-rail fuel injection systems, the third generation electric control fuel system were created with the increase of the requirment for diesel exhaust and the development of electric control fuel system in the world. Common rail systems possess more great advantages than other fuel systems since the growing of diesel exhaust requirment and economical requirment. It can not only realize stable high-pressure injection in all operating modes, but also make the system realize smart injection rule (pre-injection, post-injection and so on), consequently, the exhaust was greatly improved.In this thesis, two problems were studied on the basis of the studying the working principles, schematic design as well as device design and choice for the certain-model diesel high pressure common rail fuel injection system. The first one is the design of electric control unit (ECU) control strategy and the development of ECU control software; the second one is the fuzzy adaptive PID control for the common pressure, to design the fuzzy adaptive PID controller and to experimently studied. On the first problem, the control stratagies for the rail pressure, injection timing, injection pulse width and injection rate as well as the switching of operation modes for engines were all designed, in addition, the function of main program modules of the whole control software program was also described, as well as every function subprogram for ECU control software were all completed; On the second one, the idea and theory on the fuzzy adaptive PID control were proposed, the fuzzy adaptive PID controller was designed, and the the common pressure control was experimentally studied. The results indicated that the fuzzy adaptive PID controller has the both advantages of the PID controller and fuzzy controller. Meanwhile, it can be also concluded that the using of fuzzy adaptive PID controller makes the adjustment of common rail pressure response fast, net balance small, overshoot small, stable, good robustness, and so on.