Study On Double Clutch Transmission

Automatic transmission has always been the goal in the development ofautomotive powertrain system. With the wide application of computer technologyin the automotive industry, automatic transmission technology has developedquickly. Today, the application of automatic transmission has been more significantwhen car has been more and more popular and the number of inexperienced driverhas increased a lot.Automated Manual Transmission (AMT) has the advantage of high efficiency, lowcost and easily manufactured. So, the current manufacture equipment of manualtransmission can be adequately used and particularly suitable for companies inChina most of which use manual transmission manufacturing equipment.AMT is not powershift transmission and there is interruption of torque during theshift. So the launch performance and shift quality of AMT cannot be compared toAutomatic Transmission (AT) to some extent. Powershift AMT is the innovationand change of the conventional AMT. It inherits the advantage of high efficiencyand low cost of AMT and eliminate the power interruption of AMT during shift solargely improve the market competitiveness. The current powershift AMT has twotypes: auxiliary torque AMT and double clutch transmission (DCT).DCT is a new generation automated mechanical transmission. It inherits theadvantage of conventional AMT and has excellent shift quality and launchperformance. So it has a bright market prospect. The research of DCT is at thebeginning stage in China. Further research and manufacture of it will definitelyhave positive significance to the improvement of ability to develop automatictransmission in China.This thesis analyzes the system structure of DCT; design the mass, stiffness anddamp parameters of dual mass flywheel and completes the idle speed simulation. Ialso set up the math model of filling and draining oil processes and simulate theprocesses in Matlab/Simulink. Also, I analyze the shift process.The thesis is composed of five chapters. In the first chapter I introduce the 73Abstractdevelopment process of automatic transmission in the first instance. Then I analyzethe advantages and application prospect of DCT and propose the object,significance and content of the paper.In the second chapter I analyze the system structure of double clutch transmission.First I analyze the structure characteristic of single middle shaft DCT and discussthe power flow and shift process in the case of shift from first speed to secondspeed. Then I introduce the system structure and the basis control method of DCT.I analyze the three components of DCT hydraulic system and the workingprinciple of each part. Then I introduce three buffering methods of clutch hydraulicpressure in common use and analyze the advantages and disadvantages of everymethod.The main object of the third chapter is to design the dual mass flywheel (DMFW).Firstly I introduce the function of conventional vibration damper in the driven plateof clutch and analyze the disadvantages of single stage linear vibration damper andthe functions of each stage in the multi-stage nonlinear vibration damper. Then Iintroduce the basis structure of DMFW and explain the advantages of it from theaspects of avoiding resonance in idle speed, reducing the stiffness of spring andusing gear oil. I determine the mass, stiffness and damp parameters of DMFWaccording to the parameter selecting principle and carry through vibrationsimulation in idle speed on the basis of setting up the math model of powertrainsystem. The result shows that the DMFW is far better than the conventionalvibration damper.The fourth chapter is the research of clutch hydraulic system. In the first instance Ianalyze the components of clutch hydraulic system and the control methods offilling and draining oil of clutch. Then I introduce the structure and workingprinciple of high-speed valve (HSV) and analyze the stat...