Research On Nonuniformity Control Strategy Of High Pressure Common Rail Diesel Engine

The non-uniformity work in cylinders is a common problem for the engine. For the diesel without common rail system, the injection pressure is effected by the cam lines and engine speed, it is difficult to control the injection pressure and injection uniformity for each cylinder. The high pressure common rail technology which applied to electronically controlled diesel engine, made it possible for the precise control of work uniform in cylinders of the engine. It is an important issue that how to control the non-uniformity work of the engine, and how to design real effective control strategy for the development of electronic control system in common rail diesel.The YN30CR electronically controlled diesel engine of Yunnei Power was used as the study object, the non-uniform signal which was extracted from the engine by preliminary research of subject group is used as the starting point for the study. The functional requirements of the non-uniform control strategy were analyzed to clarify the research purposes. According to the control requirements, the functional partitioning method was used to research the enable conditions of control, the work areas of control strategy, the calculation method of fuel correction, the correction differences for each work area of control strategy, as well as the reasonableness of the correction results. The control strategy was subdivided into peak defining module, integration zoning module, PI integral module, weights calculation module and the limiting module of integration results.The uniform control of cylinders was regarded as the control target of the research, the digital signal processing and system dynamics were regarded as the theory basis, the graphical programming software Lab VIEW was chosen as study tools for the preliminary studies of the control strategy, the professional develop software ASCET was chosen as the later period develop tool for automotive electronic control system of the control strategy. Through the comparative analysis to the results of these two control software, accuracy and verifiability of the program has been enhanced.According to the results of Lab VIEW research software and ASCET develop software, two sets of verification process have been designed. Bench validation results showed that the correction oil which has been obtained by the two-stage control strategy can be timely and effective eliminating the work non-uniformity of each cylinder. Through the comparative analysis of the two authentication process, the real-time performance and verifiability of the control strategy were further proved.