Dynamic Analysis Of New Chain EMCVT And Integration And Debugging Of Its Product Level Controller

The origin of CVT can be traced back to the 19th century.Due to the limitation of manufacturing and control technology,CVT technology was not widely used.In the 1980s,CVT technology developed rapidly,and many key technologies made breakthroughs.CVT market originated in Japan and Europe,and now it spreads all over the world.The CVT technology of automobile has become a research hotspot.The research object of this paper is the electro-mechanical controlled metal chain continuously variable transmission(EMCVT),which adopts a new speed control mechanism and automatic pressure structure.Compared with the hydraulic control system,the oil pump and other devices are abandoned.The structure features:(1)lower fuel consumption;(2)lower manufacturing cost;(3)automatic follow-up control of clamping force.The clamping force control strategy can be omitted and the control process can be simplified.This paper focuses on the following aspects:First of all,the EMCVT with a new automatic compression mechanism is designed to remove the disc spring compression mechanism,which can reduce the power demand of speed ratio motor and the difficulty and instability of program control.In theory,the dynamic characteristics of CVT and the elastohydrodynamic lubrication analysis of the contact between the metal chain and the cone disk drive are analyzed,and the relevant mathematical model is established;the elastohydrodynamic lubrication equation is solved by FORTRAN language,and the influence of non-Newtonian fluid elastohydrodynamic lubrication of lubricating oil on CVT transmission is studied.Secondly,the bare metal EMCVT controller is integrated and debugged according to the V model.Integration work:on the one hand,the control strategy is put forward,the equivalent logic circuit model is established on the Simulink platform,the C code is generated after the C code is set up,and the simulation is verified to be correct.On the other hand,compile the hardware abstraction layer(including IO driver module,analog-to-digital conversion,PWM,can,general timing module,etc.)at the bottom of the controller,copy the generated code into the code warrior ide integrated software,link,compile and verify the whole code file,and then copy it into the controller.Finally,a series of testing and debugging work is completed according to the hardware debugging sequence.Finally,a series of functional test experiments were carried out on the speed regulation characteristics of the continuously variable transmission and the automatic pressurization mechanism.Through these test experiments,the mathematical model of automatic pressurization,the factors affecting the pressurization curve,the potential problems of the gearbox are explored,and the direction for further design and improvement of the transmission is provided.The automatic pressurized mechanical electronically controlled continuously variable transmission has great application prospects due to its high transmission efficiency and simple control mode,so there will be more and more follow-up research on such a transmission.The analysis results of this paper have certain reference significance for future related research.