Research On Self-Adaptive Shift Schedule In Automated Mechanical Transmission Of Heavy-Duty Commercial Vehicle

In our country, commercial vehicles include heavy-duty commercial vehicles, middle-duty commercial vehicles, light-duty commercial vehicles and mini commercial vehicles. Heavy-duty commercial vehicles market in china has been growing up rapidly in these years. With the increase of the fuel price, heavier emissions regulations, continued pressure on operating costs, increasing traffic congestion, and a shortage of skilled drivers, these changes will take place in the engine , the exhaust gas treatment system, and the transmission on vehicles, especially middle-duty and heavy-duty commercial vehicles.At the aspect of the transmission, we look at automated Mechanical transmission (AMT) attentively, which is low produce cost, high efficient, can shift and operate clutches automatically. Till now, the vehicle factories in our country have no ability to manufacture the automatic gearbox. In recent years, many manufacturers have been trying to seek automatic products, which suit our country situation and can be developed independently. In respect that we have many Mechanical transmission plants, for its high efficiency, low cost, and easier manufacture, AMT is considered to be the right product, which is the most suitable for us and has greatest potential in the development of industry.A new technology for AMT is non-clutch operation, and this technology bases on customary AMT. In the process of gear-shifting torque,the clutch does not separate from the engine and we need to adjust the running speed and the torque of the engine only. Eaton Company already uses this new technology in one transmission. If we put the new technology in commercial vehicles, there will be great meaning in automatic transmission of the commercial vehicles. Shift schedule decides the time to shift and it is the soul of the automatic transmission. When the AMT is working, by comparing the states of the vehicle with the optimal shift schedule, the AMT decides the optimal shift time and achieves the shift automatically. This will lessen the tiredness of the driver and improve the safety. Consequently, how to establish the best shift schedule is a crucial research aspect of AMT.The shift schedule of the automatic transmission comes from 1-parameter,2-parameter to 3-parameter operation. In recent years, more and more researchers pay attention to intelligent control theory, and they want put this theory in shift schedule to make the shift schedule better.Combined with the national 863 project, Research and Development of AMT, this paper aims at the shift schedule of the AMT in heavy-duty commercial vehicles. According as the characteristic of the engine and the parameter of the vehicle, this paper established the traditional shift schedule and the self-adaptive shift schedule and according to this regulation simulates actual situation of the vehicle. The outcome shows these regulations are feasible. This paper has researched on these aspects as follows:⑴At first the development history and the present conditions of automatic transmission are introduced in detail. At the same time, this paper analyses the makeup, the principium and the technique of AMT. At last the excellence and principium of the technique (non-clutch operated AMT) are discussed.⑵R esearch on shift schedule of automatic transmissionThis paper analyses the characteristics of some kinds of shift schedules. Shift schedule is realized by electronic shift system.⑶The establishment of the shift scheduleShift schedule is the basic part of automatic transmission. In this paper, dynamic capability and fuel consumption are considered. According as torque and fuel consumption characteristics of the engine, 2-parameter traditional shift schedule for the commercial vehicle is obtained. This regulation can be used in electronic control unit (TCU) directly and there are certain significance and actual value.Then this paper designs the self-adaptive shift schedule.⑷M odeling of gear-shift regulation and vehicleFor qualitatively researching on the effectiveness of the shift schedule control system designed, and proceeding the simplification to the very complicated vehicle system, and putting forward the some assumption conditions of the simplification. At the same time keeps its general dynamic characteristics. And according to the construction parameter and technique data of one commercial vehicle, making use of the language of MATLAB with the tool of SIMULINK, for engine, transmission, shift schedule, whole vehicle dynamic model to proceed to set up models in SIMULINK.⑸T he simulation of shift schedule and the analysisFor the sake of verifying the rationality and possibilities of the shift schedule, this paper makes use of the models above. On the whole vehicle model this paper set up the simulation to test the regulation in some simulative situation. By the simulation analysis, the simulation result indicates that the simulation model and the shift schedule designed in the article are reasonable.In conclusion, this paper studied the shift schedule of the automated mechanical transmission systematically on the basis of former research. In the paper, only the above work is completed because of limited time and the difficulty of AMT system. Further research should be continued in order to improve the properties of the AMT system and vehicle in the future.