Research On Automatic Transmission Technology And Electronic Control System Of Engineering Vehicle

The engineering vehicles, such as car loader, the bulldozer, the road roller, in order to enhance the adaptation capability of the intensity load, its main transmission system usually uses hydro-mechanical transmission form. However, the hydro-mechanical transmission efficiency is low, particularly when meeting the high strength load that need the transmission system output the biggish efficiency, by contrast the hydro-mechanical strength bending moment transmission efficiency drops large scale, even reduces to zero. It causes the work efficiency to reduce,and make the energy waste. The waste energy transforms to the quantity of heat, causing the oil temperature ascend,make the machine working conditions worsen and make the failure rate rise. Therefore engineering vehicle must use the automatic transmission technology, which can enhance the productivity and solve problems which appear above. But the engineering vehicle is the traction machinery, which is different from the automobile and other carrier vehicles. So it cannot imitate the automatic transmission technology of the automobile. We should hold the work characteristic of the low speed heavy load and the load rapid change of engineering vehicle, discover superiorly the rule of shifts gears, which can enhance the power and the efficiency of engineering vehicle large scale.This dissertation unifies Doctor Foundation project: Study on Automatic Transmission Technology with Four-parameter of Engineering Vehicle,the project named"Study on electrically controlled method of Enhancing power and the efficient of Hydro-mechanical drive system"supported by Foundation ofBackbone Teacher Foundation of Ministry of Education. This dissertation based on the in-depth research of hydro-mechanical transmission drive system characteristic of engineering vehicle, in view of the questions of low efficiency the engineering vehicle transmission, it has obtained the realization that automatic transmission technology of engineering vehicle is inevitable trend. This dissertation has carried on the detailed analysis to transmission system drive power of engineering vehicle, has established the corresponding mathematical model, has formulated overall model plan of transmission system of engineering vehicle. Thus it proposes the rule that energy conservation and shifts gears of engineering vehicle. Basing on the research of three-parameter auto shift schedule, this paper added a new parameter—the pressure of the oil pump, elaborates the principle of Four-parameter auto shift gears, and gives the rule of Four-parameter shift gears.This dissertation uses the experimental method to get the point of Four-parameter the auto shift schedule and shift strategy. Based on the strategy, used PLC, it develops the electronic control unit(ECU)of automatic transmission, and designs from its hardware and the software, these two aspects.A testing experiment on test-bench of automatic transmission control system is carried out. The test result validate the accuracy of the theory and the rationality of ECU.Each chapter of the dissertation is introduced in the following context. The first chapter IntroductionBased on the summary and synthesizes of automatic transmission technology of domestic and foreign vehicles, this text discusses the classification,characte- ristics,application,the present research condition and the development trend of the automatic gearbox,also discusses the technique application of the automatic gearbox in the engineering vehicle, include the purpose,Realistic meaning of the technique of the automatic gearbox and analyze the key problem of the technique of the engineering vehicle. Finally, the main contents are made certain based on the research results of the predecessor.The second chapter The analysis of the power of transmission system of engineering vehicleFirstly, the dissertation introduces the characteristic and the composition of transmission system of ZL50 car loader. In this foundation, the dissertation is onthe basis of external characteristic and the load characteristics test data of diesel engine which provides by the factory, carrying on the fitting to obtain the table state external characteristics of diesel engine and the mathematical model of diesel engine velocity modulation characteristic. By means of theory analysis of primitive characteristic of hydro-mechanical engine-converter, it elaborates its low efficiency and the solution. It analyzes the characteristics of input and output which the engine and the hydro-mechanical engine-converter that work together.Next it introduces the principle of work of dead axle type gear box and the gear pump, having established the mathematical model separately to them which lies the rationale to the rule of four-parameter gear-shifting strategy.The third chapter the research on the automatic shift gear of the engineering vehicle with four parameterFirstly, the dissertation introduces the classification of rule of automobile gear-shifting., and points out that some questions which engineering vehicle apply automatic gear-shifting transmission rule. Secondly this text introduces the regulation of economic energy shift gear in the engineering vehicle,and elaborates the meaning of the theories shifts gear regulation and the realization economy energy.The dissertation introduces the method of preventing the circulation gear-shifting and the significance of the realization of the rule that energy conservation gear-shifting. Basing on the research of three-parameter gear-shifting rule, this paper adds a new parameter—the work pump, elaborates the principle of four-parameter automatic gear-shifting,the rule of four-parameter gear-shifting. And introduces the method to prevent to shift gear circularly.Finally, a testing experiment on is carried out to validate the points of automatic shift and shift strategy.The fourth chapter The design of automatic transmission electronic control system It is the simple introduction for the characteristic of PLC and the application domain and the basic composition, elaborating its principle of work.It has carried on the design separately to the hardware and the software of automatic transmission control system Hardware design includes PLC choice, the allotment of the I/O address,the design of power circuit, sensor installment, the design ofsampling electric circuit and the design of output actuation control circuit. The software design includes the overall engineering design, the design of sampling subroutine structure and the design of gear-shifting that between the delay routine and the files the time -delay procedure.The fifth chapter Test-bench of automatic transmission electronic control systemThe text introduces the constitution of automatic transmission test platform and the main performance index, the instrument that the laboratory use and the measurement of various input parameters.Have given an account of the content of testing experiment made by stage in engineering vehicle drive, having carried out analysis on test result. The result indicated that the rule of gear-shifting is correct, which is able to make the efficiency of hydro-mechanical engine-converter maintain at the highly effective area. It confirms that the feasibility of gear-shifting delay and delay between the stalls. Automatic transmission electronic control system that based on the law can be adjusted according to changes in working conditions stalls. It can realize gear-shifting automatically, be accurate, reliable and promptly.The sixth chapter Summary and the forecastChapter six is the summary of the whole dissertation. Suggestion and prospect of automatic transmission research are given.