CVT Flow Active Control System Dynamic Property Simulation Analysis Based On Double-pump

Continuously variable transmission (CVT) automatically and continuouslychange speed ratio according to automobile run condition, which make engine runaccording to the optimum economy cure or the optimum performance cure. However,CVT systems currently exist a large power loss at the present,where the hydraulicsystem leads to about60%power losses of the CVT total power loss. Meanwhile,other types of automatic transmission is also facing difficulty that solved this commonproblem.Therefore, the effective method to solve this problem is the development ofdouble pump oil technology. In order to reduce the power loss of CVT system and doactive control to the system flow,which is based on the application of variablepump control technology, the main results of this thesis are as follows.1.Briefly introduced the CVT research background and its classification，summarize the research results at home and abroad;sum up the prospect of CVThydraulic system and pointed out that the technological research on metal beltCVT flow active control system is of great significance for improving the metal beltCVT performance.2. Analyze the characteristics of CVT ratio and torque,study the hydraulic systempower matching control strategy and define the factor on CVT hydraulic systempower loss. Designed an Energy-saving type active flow control structure of the CVThydraulic system for reducing the hydraulic system overflow losses by the applicationof variable pump control technology.3.The reversing valve which is the core component of CVT active flow controlsystem is designend and the structure parameters is determined by theoreticalcalculations.Design the throttling groove and calculate the flow area by the use ofMATLAB.After that,define the principle about select the optimal flow area.Establishthe simulation model and do simulation analysis based on the AMEsim simulationenvironment.4. Establish the mathmatical model and simulation model of speed ratio controlvalve and clamping force valve for the further study;The dynamic model ofdouble-pump is built on the basis of analyzing CVT hydraulic system flowcharacteristic.Establish the simulation model of the CVT active flow controlsystem,what the focus is on the analysis about the effect of the CVT active flowcontrol system.Analyse the impact of differential pressure in the orificeon the systemflow characteristic.The viscous damping coefficient,spool quality, groove width andthe main throttle valve spring stiffness as factors affecting the dynamic characteristics of the system are analyzed when the pump source switched.Do comparative analysisto the two kinds of CVT hydraulic system for finding out the control effect of theefficient and energy-saving CVT flow active control system.5.Design the CVT flow active control experiment system,which including fiveindependent system：mechanical tansmission system，sensor system，informationcollection and processing system，hydraulic system and control system，At the sametime， select the core components and dfine the text content.All of the work lay thefoundation of bench test for CVT flow active control system on the next step.