Research On Energy Loss Prediction Method Of Continuously Variable Transmission

Due to its continuous valuable ratio, metal-belt continuous valuable transmission can make the engine work in the economic area. But CVT’s energy loss is so high that the fuel economy of vehicle equipped with CVT has not been improved. In order to stand out its strength, it is necessary to further study the mechanism and the law of energy loss.According to the research project of “The Technology Trends Research Of Passenger Car’s Transmission”, metal-belt continuous valuable transmission was regarded as the research object, its structure principle was analyzed, the mechanism of energy loss was researched, the prediction model was established, which can theoretically support the development of CVT. In this paper, the main research contents are as follows:1) Overseas and domestic research status of transmission energy loss was summarized, and CVT’s strength among automatic transmission was researched. The subject of this dissertation was educed;2) Basic structure 、 kinematic relations 、 belt transmission relationship of CVT were expounded; The function relation between speed ratio and belt wheel running radius was inferred;3) Energy loss of CVT was analyzed, whereby, wedging loss result from pulley deformation of shifting mechanism, Friction torque loss between steel belt and pulley, oil pump oil loss of hydraulic control system was emphatically analyzed. Mechanism, model and theoretical formula of the loss were researched;4) Based on the mechanism of loss, the theoretical modeling and simulation analysis research of CVT energy loss were done. A bench test for a type of CVT was done and trend consistency analysis was done.The research shows that: In and out of the pulley friction loss increases with the increase of speed ratio, With the increase of friction coefficient significantly reduced before they are stable,Transfer torque friction loss as the ratio increases As the friction coefficient increases, Increase at a faster rate and small ratio condition Pump oil loss is affected by lubricant dynamic viscosity、engine speed、engine torque and speed ratio. The correction of prediction model was proved by experiment. There is good consistency between experimental results with the simulation prediction results.