Study On Shift Schedule With Multi-Modes Of Automatic Transmission For Loader

Construction vehicles are always seen in engineering construction, mines, docks,construction and other occasions, and among these vehicles, the loader is the mostwidely used, which make great contribution to accelerate the construction of thenational economy and modernization. As the complicated operation conditions and badwork environment of loader, loader’s economic performance and efficiency can’t beguaranteed, and the operator’s safety can’t be guaranteed either. What’s worse, thefluctuation of load and speed are in a large range when loader works, which distractsthe operator’s attention and increase the intensity of labor. The emergence andapplication of automatic transmission technology solved the above problem in a certainextent, and parts of the foreign loaders have been equipped with automatic transmissionsystem. However, due to the backward technology of our country, automatictransmission technology is not widely used, thus it is extremely urgent to studyautomatic transmission technology. As the working state of the loader are complex andvaried, every working condition has different requirements, so there is no a perfectautomatic transmission technology which can meet loader’s all needs, thus the study ofautomatic transmission of loader is significant.In the traditional loader transmission system, the match of diesel engine and torqueconverter can’t be always guaranteed to work in a good condition, which reduces theloader’s performance greatly. Aiming at the shortcomings of the current loaderautomatic transmission technology, a kind of automatic transmission technology whichcould adapt to many working condition was put forward in this thesis, and the shiftschedule was studied in detail. This automatic transmission with multi-models wasproposed to solve the problem mentioned above, and besides it could ensure the matchof diesel engine and torque converter always working in a reasonable condition at every mode. The main contents and conclusions of this study are as follows:1. Performance analysis of electronic diesel injection engineBased on the feature that electrical diesel injection engine could be preciselycontrolled by parameters such as its diesel injection quantity, electrical diesel injectionengine was divided into three operating modes: dynamic mode, middle mode, economicmode, and loader’s working mode was divided into three modes based on these. Themode of maximum torque and the maximum rated speed of the electrical dieselinjection engine was treated as dynamic mode, the mode of a certain amount of reducingof the torque and rotational speed was regarded as middle mode, the economic modewas defined as mode of the minimum torque and the minimum rotational speed. Fuelconsumption data was obtained according to the universal characteristic curves ofengine (MAP chart) based on the relationship of the rotational speed and torque at eachmode. The torque characteristics curves and fuel consumption curves of electrical dieselinjection engine were fitted out by mains of least square method at each mode, thegoverning characteristics curves were also obtained according to a10%speed droop,and all the results prepared for the future research.2. The performance of composite torque converter and its match with the dieselengine under every modeThe original response cures of torque converter has been fitted by means of a non-linear least square method using the pallet experimental data of the composite torqueconverter, the input characteristics curve and the mathematical model were alsoobtained. Matching calculation of diesel engine and hydraulic torque converter at everymode were done, and the input characteristic cures of the two parts were obtained. Then,the output characteristic cures of the two parts were obtained based on the commonoperating point data. The solution of matching calculation showed that the matchingwork of the diesel engine and the composite torque converter were always in goodworking condition under every mode, not only the good dynamic performance but alsothe good economic characteristics were guaranteed.3. The calculation of traction characteristics for loader and the design andanalysis of shift schedule with multi-modes of automatic transmission According to the selected transmission system parameters and vehicle parametersof the loader, the resistance of loader was calculated, and traction characteristics undereach mode were obtained. Shift schedule with multi-modes of automatic transmissionfor loader was designed, as the dynamic mode and middle mode were used in both fullload working and haul transportation working, economic mode was only used in haultransportation working, so dynamic mode and middle mode were three-parameter shiftschedule(speed, throttle opening and load factor) and economic mode was two-parameter shift schedule(speed and throttle opening), besides, best fuel economy shiftschedule for economic mode was also designed. Comparative analysis of differentmode shift schedule at same working condition was done, the maximum traction andtop speed could be reached161.4kN and43.3km/h when loader worked at dynamicmode; the data of middle mode were145.27kN and37.9km/h; the data of the data ofeconomic mode dropped to113.5kN and31.6km/h. But on the other side, the fuelconsumption per100km at constant speed of dynamic mode, middle mode andeconomic mode could be reached40.7L,39L and37.1L at least. These resultsconformed to the original design goal of shift schedule with multi-modes, and theschedule was proved to be a very reasonable shift schedule of automatic transmission.4. The simulation analysis of shift schedule with multi-modes of automatictransmission for loaderIn order to verify the rationality and feasibility of the multi-modes automatictransmission shift schedule proposed in this master thesis, the simulation analysis wasalso proceed. The loader transmission system simulation model was set up byMATLAB/SIMULINK and MATLAB/STATEFLOW toolbox based on dynamic modelof loader transmission system. At a given working condition, the simulation analysis ofeach mode was done respectively, and the simulation results showed that the shiftschedule with multi-modes of automatic transmission for loader got the desired goal, itwas reasonable and had high application value for practical engineering.