Computer Model And Study On Control Strategy Of Metal-Belt Type CVT

In today’s society, the car has become an important part of life. People are nolonger just attached to the car ’s fuel economy and power, also put forward higherrequirements to automobile driving comfort, especially the car enters a family.Personal driver appeared in large numbers, the automatic car needs urgent. Becausemetal belt type continuously variable transmission (CVT: Continuously VariableTransmission) has the advantages of simple structure, convenient operation, hightransmission efficiency, energy saving and environmental protection and otheradvantages. It is an ideal transmission so it become the first choice for people. Inrecent years it has been the rapid development. This paper studies the selection ofmetal belt type CVT as the research object. And in view of the complex roadconditions, puts forward the comprehensive control strategy model to balance theeconomy and power demand.This paper first reviewed a large number of data. The metal belt type CVT’seconomy, power, transmission efficiency, reliability and life expectancy, emissionsand cost and other aspects of the advantages and the domestic and foreigndevelopment condition and future development trend are discussed.Secondly, the working principle of the metal belt type continuously variabletransmission is analyzed according to it’s structure. And give a detailed analysis ofmetal belt continuously variable transmission’s control technology for the modelingand simulation provides a good theoretical basis.Again, carry on the comparative analysis to the electro-hydraulic system that getthe effect of CVT control performances. And focuses on analysis of electric controlsystem including the structure of CVT electronic control system, interface circuit andsoftware design. As a result of ratio control get great influence on the integratedcontrol strategy. This paper focuses on the analysis of PID speed controller. Includingthe PID control principle, changing rate of speed ratio of PID control and PID controlalgorithms.Then, in the MATLAB environment take experimental data processing of engineand get the engine output torque, output power, fuel consumption rate of the datamodel, get the engine output torque MAP. Then get the best economic line and theoptimal power line and establish a vehicle model in the Matlab/Simulink. So that we can take the simulation analysis and verification of the control strategy.Finally, in order to adapt to the process of moving vehicle often meet roadfriction resistance changes in China’s vast rural areas and urban areas, we put forwardthe integrated control strategy when road friction resistance changes. In order to solvethe malpractice of the driver simply choose economy mode or dynamic mode and dueto the driver’s skill level and on the road accurate degree and the driver of theindividual differences can make power transmission system control effect can not beachieved best. And according to the established vehicle model, typical workingconditions of road friction resistance changes were simulated and analyzed. Theresults show that the economic model showed better economy in small power demandbut cannot provide good dynamic performance in big power demand. Dynamic modelcan provide better power in big power demand but cannot have good economy insmall power demand. Only the integrated control strategy can get the advantages ofthe fuel economy and power. So the result demonstrates the feasibility of integratedcontrol strategy.