Study On Control Method Of Transmission Ratio For Metal Pushing V-belt CVT

Metal pushing v-belt cvt as a car ideal variable speed device, Can make be equippedcar power, economy and emission relative to other equipment automatic and manualtransmission cars more excellent, so it has always been the major automotive manufacturersas high performance car a big selling point and widely promoted. Metal pushing V-belt CVTby the use of the electro-hydraulic control system, can according to car driving moment anyoperation regulation requirements Metal pushing V-belt CVT of the transmission ratio, makethe engine work in the best area, effectively improve the engine fuel consumption andemissions pests.Metal belt type Metal pushing V-belt CVT of transmission ratio for driven pulleysand active belt round circle radius of the quarter than. In the metal belt limit function ofactive wheel and driven pulley position and Metal pushing V-belt CVT ratio has one-to-onerelationship, so by getting active the position of the wheel information, can be reliablypositioning the current gear mechanisms of the transmission ratio, dynamic implementationon the transmission ratio of the control, is the essence of Metal pushing V-belt CVT control.Previous control strategy is a new initiative wheel and the speed of the driven pulley thaninstead of transmission ratio, realize the vehicle transmission control, but, owing to theengine speed change drastically, and large variation, and at the same time by inertial factors,the actual speed is larger than the measurement of error, with its instead of transmission ratiocontrol, poor stability, accuracy is not high, the effect is not ideal. The actual ratio and targettransmission ratio can be the active wheel positional information calibration. The goal of theinitiative of the wheel speed corresponding position information as the control target, to agreat extent, simplify control model, and can improve the performance of the whole systemcontrol.In this paper based on the previous studies, launched the following around thetransmission ratio control research:1, in reading at home and abroad on the basis of a large number of documents, thispaper introduces the development course of is variable transmission, the common automatictransmission of comparison, analyzes the metal belt type Metal pushing V-belt CVT advantages and key control technology.2, analyzes the metal belt type Metal pushing V-belt CVT structure and variablespeed principle, the transmission ratio control principle, realize the control of thetransmission ratio analysis strategy and method, for all kinds of control strategy in thecomparison, offered to active wheel for control of the target displacement ratio controlstrategy.The CVT transmission speed inside the system analyzed the structure, through themathematical formula proved transmission ratio and active round the corresponding relationbetween displacement one, in order to be able to experiment on the stage in the CVTtransmission ratio control effect of verification, the first active wheel displacement andtransmission ratio of the relationship between the calibration. And the PID control theory isbriefly described, key content is how to choose the control parameters.4, in order to verify the transmission ratio control theory based on displacement ofthe control effect, use of matlab software engine simulation model are established, CVT-thetransmission ratio, the simulation model of PID control model, and will they even get CVTset up the speed ratio of PID control matlab Simulink model, start to ramp, urgentacceleration and cycle working conditions is the simulation experiment, proved the controlstrategy of the effect.5, and further, we in the transmission ratio and active wheel relationship betweendisplacement calibration finish on the basis of the cone to active wheel moving part tocontrol the amount of displacement Metal pushing V-belt CVT ratio control experiment, inorder to guarantee CVT have enough clamping force, driven pulley oil cylinder pressureover surplus keep constant, only by changing the active wheel electromagnetic valve realizethe control voltage transmission ratio, comparing the different working conditions thecontrol effect of test output, confirmed to active cone wheel moving part displacementcontrol target for transmission ratio of quantity control strategy in the system response speed,smooth action, overshoot control and so on, are better than transmission ratio control effect.