Research On Four-parameter Automatic Shift Control System Of Construction Vehicle

The environment of the construction vehicle working is very hard, as well asthe outer load varies sharply. In order to adapt the instability of the outer load, atorque is added in the transmission system. But the efficiency of the transmissionsystem decreases, especially in the high strength load. In the same way, theefficiency of the torque decreases abruptly if the gear can't shift up quickly in highspeed and low load situation. In order to keep the torque working in the range ofhigh efficiency, multi-gears should be applied, at the same time, the station of thegear changed frequently according to the outer load. The complexity of theoperation, the frequent gear-shifting of the drivers result in high labor intension andlow working efficiency in which it is difficult to maintain high driving efficiency.In order to solve the problem of the low efficiency of transmission system, it isurgent to adopt automatic transmission technology to construction vehicle to adaptspecific working environment and improve vehicle performance.This dissertation bases on the doctor station fund project (No. 20020183003)of"Study on Automatic Shift Technology with Four-parameter of ConstructionVehicle" , and the national natural science fund project (No.59705005) of"electronic control for saving energy of Construction vehicle", the dissertationstudies the theory of automatic shift technology with four four-parameter ofconstruction vehicle , and performs a new shift strategy, and draws the chart for therule of the automatic shift by experiment, and develops the electronic control unit(ECU)of automatic transmission based on the rule. Finally, a testing experimenton test-bench of transmission system is carried out to validate the availability ofrule and test the integrated performance of automatic transmission control system.Each chapter of the dissertation is introduced in the following contextIn chapter one, the development trends of vehicle's automatic transmissioninside and outside nation are introduced according to the phylogeny of automatictransmission technology. The significance of adopting automatic transmission onconstruction vehicle and the deficiency is discovered. Finally, the main contents aremade certain based on the research results of the predecessor.In chapter two, the attribute and structure of the transmission system are firstlyintroduced as the example of the Construction vehicle of ZL50. Then thedissertation discussed the working characteristics diesel engine, especially which intiming characteristic. After that the torque and the shift gear-box is discussed. Atlast main contents of this dissertation is set forth.In chapter three, the Shift Schedule for four parameters of construction vehicleis discussed. Theoretic research of construction vehicle automatic transmission isthe key of this chapter. Firstly, the developmental course of the automatictransmission control system for vehicle is expatiated. Secondly the trait and the lowefficiency of the torque are discussed. Thirdly , the automatic shifting schedule ofconstruction vehicle are studied after that the characteristics and application rangeof single-parameter, double-parameter, three-parameter and four-parametergear-shifting strategy is made a summary. Finally, we draw up the chart for the ruleof the automatic shift by the method of experiment and graphics. The chapter is thekey and the base in the dissertation.In chapter four, the hardware for the automatic transmission electronics controlsystem is developed, and this chapter is the key content of this dissertation. Takethe single-chip Microcomputer as the main control chip , The hardware circuitdesign on the construction vehicle was systematically explained in an all-roundway, and the module method have been adopted in the course of the designing. Tosure the reliability of the system in the hard working conditions, we briefly state thesettlement for anti-interference of the control system based on the microprocessorsingle chip. The watchdog chip of MAX813L is applied in the design, and thephotoelectric insulation is adopt in the input and output channels, the ECU isencapsulated by metal box. The interference is shielded and the three modes ofinterfere is cut off..In the chapter five, the software design for the control system is developed bythe assemble language, in which the module method have been adopted. Accordingto the former chapter, we briefly state the software settlement for anti-interferenceof the control system : software filter for wave shape is used in the input channelsof the impeller and turbine of the torque converter, Average value method is used inthe channels of pump pressure and the engine throttle opening radio to voidexclude the incidental error. Many other methods such as digit filter wave, softwareredundancy, software trap and so on are also used in the main control program.In the chapter six, an experimental study for automatic transmission electroniccontrol system is carried out. This chapter is a practice to complete research. Anexperiment on the test-bench for hydro-mechanical transmission is carried outaiming at proving the feasibility of automatic shift control system of constructionvehicle with four-parameter and the ECU designed in the dissertation.The results of experiment show that the control system for automatic shiftcontrol system of construction vehicle with four-parameter can improve theefficiency of transmission system further. On the other way, the shift strategiesabove are applied to carry through gear-decision, which can realize theoptimization of gearbox's gear, namely, reach control anticipative aim.Chapter seven is the summary of the whole dissertation. Suggestion andprospect of automatic transmission research are given.