Study On Electro-hydraulic System Of Pump Controlled CVT

The metal belt continuously variable transmission as an important member of theautomatic transmission, has been developed and used by various automobile manufacturers.The car equipped with CVT has excellent driving experience, no shift frustration feelingand had a good ride comfort and comfort. However, in terms of economic, the CVT canmake the engine work online at the lowest fuel consumption and improve fuel efficiency,but the powertrain efficiency of car has not been improved. Due to the efficiency of CVTelectro-hydraulic system is low. In addition to the CVT mechanical energy losses, and theCVT transmission organizations need a great deal of pressure support to avoid lowclamping forc. And the valve control circuit has large overflow loss in practical work,especially the engine speed was increased. Not only lead to loss higher energy and increasefuel consumption, but also make hydraulic system module high oil temperature rise andaffect the CVT hydraulic system to work properly, and the transmission reliability wasreduced.In this paper, the principle of the hydraulic system is redesigned. Using the pumpcontrolled circuit to replace valve circuit, making the system power will be able to get abetter match, and reducing the CVT hydraulic energy losses.This paper puts forward a new type of CVT electro-hydraulic system, the mainresearch content includes the following aspects:1) Through reading a large number of domestic and foreign literature, understand thebasic working principle of the metal belt continuously variable transmission, and analyzedmain energy distribution and relevant improvement measures.2) In order to reduce the energy consumption of hydraulic system, designed a newtype of pump control hydraulic circuit system and computed system main componentsparameters and material selection. Provide the basis for modeling and simulation ofhydraulic system, and provide test prototype.3) Using Matlab/Simulink simulation module to simulate the hydraulic circuit system,and validated of design parameters on the dynamic response of the control effect, finallythe simulation analysis of the vehicle.4) Completed the pump controlled hydraulic system controller produced by usingfreescale microcontroller, including the design of the controller hardware and software.Andfinally through the controller to complete the speed test, analyzed the results.