A Dissertation For The Degree Of M.Eng Design And Research On Digital Speed Governor For Diesel Engine

Today environmental pollution and general energy crisis is becoming more and more serious. This calls for a increasingly high demand of emission performance of diesel engines. The electronic control technology is an effective way to improve the emission performance of diesel engines. According to the laggard development of digital electronic control system for diesel engines and the low-level technique, research and development must be done. The speed regulation technique is just an important composing part of this electronic control system for diesel engine. With the rapid development of microelectronics technique, using microcontroller with superior performance in the speed regulation technique, adopting advanced control strategy and optimizing the entire diesel engine condition control has become the mainstream research on electronic control technique for diesel engines.Based on the analysis of current status and developing trend of speed regulation technique at home and abroad, a wide application ranged and powerful digital electronic governor which use the Freescale 16 bit high-performance microprocessors and the diesel engine 6135 as the control object has been developed. The result of engine matching test shows that the new governor is stable-performed and reliable running.Because diesel engine has the features of non-linear, time-varying, strong coupling and load fluctuation, difficulties of speed regulation of diesel engine come into being. In order to solve these difficulties, researches on speed control modes and rules have been done. With self-adaption PID control algorithm and the method of combing the resistance integral saturation with gearshift integral action, we can finally achieve the optimizing control within the scope of entire diesel engine. This also improves its stability and dynamic peformance.By using MC9S12XEP100 singlechip as the core microcontroller, the hardware and software designs of the electronic speed regulation technique in diesel engine have been to the end. It includes various types of actuators driver circuit, signal acquisition circuit of speed temperature and pressure redundant CAN Bus communication interface circuit, etc. In order to improve the portability and real-time ability of the system, the software system is completely designed by modular design method, the combination of three interruption programms, singlechip processor XGATE module technology and so on. Matching tests showed that the main technical indexes system's function and the reliability had met the expected requirement.For the convenience of controls parameter's on-line modification and monitoring of engine working state, new man-machine dialogue unit has been made by using of delphi7 on the Windows XP flat. With this unit, the users achieve the real-time display of diesel engine's main state parameters , modificate control parameters on line, read the running state and alarm messages of diesel engine, do data analysis and draw dynamic speed curve.