Study On Automatic Shift Technology With 3 Parameter Of Construction Vehicle Based On Single Chip Computer

The construction vehicles such as Wheel Loader, bulldozer andscraper etc. adopt hydraulic mechanical drive in order to improve theadaptability to heavy load. However the transmission efficiency of hydraulicdrive is very low, especially when driveline needs to supply huge powerunder heavy load, the efficiency of hydraulic torque converter contrarilydegrades largely even to zero, which makes working efficiency decreaseand energy waste.Under the project (No.59705005) of National Foundationfor Natural Sciences: Study on Construction Vehicle Electronic Control forSaving Energy and the project of Leading Teacher Foundation of Ministry ofEducation: Study on Improving the Performance of Drive and Economy ofAT System of Construction Vehicle, taking Construction Vehicle as theresearch object, aiming at improving the performance of drive and economyof it, this dissertation is the research of pure theory and experiment.　 1.　The characteristics of automatic transmission were summarized. Thefeature, developmental process, developmental status and trend, the stateof applied in construction vehicle of all kinds of automatic transmission wereintroduced according to the different sorts. After 100-year development, atpresent there are mainly three kinds of transmission: AT, AMT, CVT, andwith the advent of "IT Revolution", the intellectualized and integrated controlis the trend of automatic transmission. Automatic transmission can avoiddifference of drivers, supply better performance of ratio conversion,alleviate intension of work, improve productivity .The main researchingcontents of the dissertation were outlined. 2. The composing and character of hydrodynamic mechanicaltransmission are introduced generally. The powertrain mainly consist of62吉林大学硕士学位论文engine, hydrodynamic torque converter, transmission and drive bridge.Because of variety of tasks, the badness of working condition, unsbenchlow speed and incline of overspeed, construction vehicle usually use dieselengine with fullscale actiyator as power source. Through analyzing thecharacter of torque converter, study its action in construction vehiclehydrodynamic mechanical transmission system and the effects to itsworking condition with outside load change, adduce the reason of bringingthe working condition dot of torque converter moving high efficiency sectionto low efficiency section. 3.The state of automobile shift schedule applied in construction vehiclewas summarized. The difference between operation of construction vehicleand travel of vehicle was compared.Summing up the methods of solvinglow effeciency of toque converter anciently, and proposing a automatic shiftschedule with 3 parameter, deciding the transmission current shiftaccording to different load in order to keep the torque converter working athigh efficiency section. This kind of schedule raise the efficiency ofpowertrain of ZL50 wheel loader, so it improve the performance of drive andeconomy of the loader. 4. The working theories of PIC single chip computer control system,the realizations of software and hardware control system, the aim ofexperiment, the structure of automatic transmission experiment bench andthe main parameters of performance are summarized, the instruments usedin experiment was introduced, the demarcate experiment of all physicsquantities are made, finally the automatic shift control experiment is carriedout on test bench.Experiment prove that automatic transmission testsystem can automatically shift and maintain torque converter working withinhigh level. Furthermore, the automatic shift schedule with 3 parameter isproved to be workable.