The Research On Non-linear Model And Performance Of The Wet Clutch Engagement Process Of CVT

With the development of automobile industry, people request better automotive performance on power,efficiency,comfortableness and security. The automatic transmission can reduce the driver intensity, pertect engine and power transmission system, improve labor productivity, heighten the car's efficiency and improve automobile emissions performance and so on. Therefore,the automatic transmission is widely used. As the the key component of power train, the wet clutch's engagement performance directly effects on automatic transmission working condition, the start stability and the quality of shifts gears.In modern vehicle design process, the technology of computer simulation and performance prediction is an analysis tool which is widely used, it may reduce work time and improvement vehicle performance.The engagement performance of the wet clutch engagement process of CVT directly effects on it's working condition included the vehicle's start stability. To carry on the analysis and the simulation on CVT .The paper take a carefully research on the wet clutch's engagement performance, establishes the the wet clutch's dynamic non-linear model and .conducts the simulation to it, carry out simulation research on start stability of model CVT as work group's peoject. The paper is made up seven parts.First chapter outlines the research survey of wet clutch and its analyse, the application situation in automatic transmission and the work principle of CVT.Second chapter analyses the characteristic of wet cluth's engagement performance and its friction type , the ability of friction disk transmitting torque in three stage of extrusion, compaction and roughly contact ,in wet cluth dynamic engagement process.The analyse is the base of set up the non-linear model of wet clutch dynamic engagement.Third chapter analyses the lubricant film principle of work and the the clutch disc's supporting capacity in the wet clutch dynamic engagement process, establishes the mathematical model of the extrusion stage, compaction stage and roughly stage , the non-linear model of the wet clutch dynamic engagement process is made up of the 3 stage which thorough expresses the characteristics of wet clutch dynamic engagement. the non-linear model of the wet clutch dynamic engagement process provides basic theory for next simulation analysis.The establishment of the non-linear model of the wet clutch dynamic engagement process, thorough expresses the characteristics of wet clutch dynamic engagement. The analysis to it,will make it looks direct and careful.Fourth chapter analyses the simulation research on vehicles transmission system in the method the significance.According to the non-linear model of the wet clutch dynamic engagement process, carries on the simulations of wet clutch's friction disk lubricant film thickness, the coherent torque, the rough torque,the wet clutch dynamic engagement process torque and the wet clutch dynamic engagement process torque under different working conditions. Under different working conditions, the two friction disk groups torque's change tendency is not large, so we can obtains change tendency and the dynamic friction coefficient of friction disk group 1 and the friction disk group 2 .Fourth chapter is important on the the wet clutch dynamic engagement process ,which is be esueful to the start simulation research on CVT.The wet clutch's working condition is complex in engagement process, it is insufficient in its analyse with the theory modelling and the simulation only.We must carry on the bench test toconfirm the simulation result, which will be advantageous for the next research.Fifth chapter the approximate structure of the wet clutch engagement process test, as well , introduces the test situation of wet clutch engagement process experiment and the test result, carries on the test result analyse The test result analyse indicates that, the simulation result and the judgment on change tendency of dynamic friction coefficient in the fourth chapter is correct, the non-linear model of the wet clutch dynamic engagement process is effective.In working condition of each automobile travel mode, vehicle start is the most complex.Conducting the simulation research on start of CVT by wet clutch, may forecast automobile's stability in this complex mode, reduce the development cycle of corresponding product and development expense.Sixth chapter analysis the process of CVT start by wet clutch, establishes the dynamics model on engagement process of wet clutch, confirm the optimal pressure of the wet clutch, obtains the start time with the fuzzy method , establishes the entire vehicle simulation model, carries on the simulation analysis of CVT start by wet clutch.The simulation result indicates, start stability based on optimal pressure is better than that based on linear pressure . In the simulation process, the non-linear model of the wet clutch dynamic engagement process and dynamic friction coefficient makes it clear that the wet clutch's dynamic engagement process , enhances the precision of computation and simulation.Seventh chapter is the summary of full text,which mainly elaborated the article's prime tasks , the research results, and next research direction.The automatic transmission is used moe and more widely, as its key component, the research on wet clutch could be more and more thorough too. CVT has made graet progresses, the simulation research on will make further efforts in the future.