Study On Automatic Shift Of Construction Vehicle With Four-parameter And Single-chip Microcomputer Control System

At the project (No.59705005) named "engineering vehicle electronic control for saving energy" and supported by National Natural Science Foundation of China and Backbone Teacher Foundation of Ministry of Education, this paper suggests a Four-parameter Shift Schedule in order to solve the problem of the power of engine can not be known precisely in the early research, because the power of engine that oil pump consumes was considered as a constant in the previous studies on shift schedule. The following is the contents of my research:1. IntroductionThe characteristics of automatic transmission were summarized. The feature, developing process, developing status and trend at home and abroad, the state of applied in engineering vehicle of all kinds of automatic transmission were introduced according to the different sorts. By analyzing similarities and differences of the automobile and the construction vehicle on automatic transmission technology, the shortcoming was pointed of two-parameter shift schedule and three-parameter shift schedule, which study shift schedule based on that the power of engine that oil pump consumes was considered as a constant. The characteristics of torque converter were introduced through studying the function of torque converter in vehicular powertrain and the effect on the working condition of torque converter produced by the change of load, the reason was discovered that the working condition of torque converter moved to low efficiency range from high efficiency range. The methods were summarized that solving the problem of torque converter working in its low efficiency range. The compose of automatic transmission system of construction vehicle was introduced.2. Study on shift scheduleThis paper introduced the principle of automatic shift of construction vehicle (Optimal Drive shift principle, Optimal Economics shift principle) and the relations between them and proposed the shift control principle. After that the kinds and development of shift schedules were introduced. The shift schedules of automobile included the one-parameter shift schedule, two-parameter shift schedule and three-parameter shift schedule. But for the specificity of the construction vehicle, the shift schedules of automobile could not apply on the construction vehicle without changes. So we analyzed the condition of that and compare the differences of working conditions between the construction vehicle and the automobile. The control algorithms and the features of shift schedule applied in engineering vehicle were summarized. From the function of torque converter and transmission in vehicular powertrain, the question was discussed that maintain torque converter working in its high efficiency range by transmission shifting through the method of mathematics modeling to the whole powertrain. Four-parameter shift schedule was obtained. The characteristics and meanings of four-parameter shift schedule were summarized.3. Computer simulation of automatic transmission's control systemSystem simulation is an indispensable research tool and means while processing systemic analysis and design, new product developed and new theory validated. The objective and significance of computer simulation applied in AT developing technology were explained. The essentials of computer simulation were summarized. The relationship between computer simulation and experiment was discussed. The task of computer simulation was brought forward. The modeling principle was explained. The structure of simulation was determined. On the basis of modeling hypothesis, vehicular powertrain dynamic model was built. The models of engine and torque converter were obtained by system identification. The load model of simulation system was obtained by analyzing vehicular diversified running resistance. Kinetic equations of powertrain were obtained. Shift-control model was determined according to efficiency shift schedule. Vehicular powertrain dynamics simulation software VPSS was developed based on the package of Matlab/Simulink.