Research On Fault Diagnosis And Fault Disposal Of New 8 Speed DCT

Dual Clutch Transmission(DCT)has many advantages: high transmission efficiency,power without interruption,good comfort and so on;so it has been rapidly developed during recent years.However,the structure of DCT is complex,it is difficult to dismantle the fault,and the auto fault diagnosis system has the diagnosis blind spot,so it is very important to study the DCT fault diagnosis and fault disposal.This paper studies the fault diagnosis and fault disposal of the new 8-speed DCT.The DCT is composed of three systems: mechanical,hydraulic and electronic control.In this paper,three kinds of fault diagnosis methods based on system knowledge,analytic model and signal processing are used to carry out research and realize real-time fault diagnosis and disposal.Not only can improve the driving safety and convenience,and can help vehicle maintenance.The specific research and achievements of this paper are summarized as follows:(1)The composition and working philosophy of the mechanical,hydraulic and electronic control systems of the new 8-speed DCT are introduced respectively.The research status of DCT and DCT fault diagnosis is analyzed,and the fault diagnosis technology is summarized.(2)The classical fuzzy fault tree analysis based on system knowledge is used to analyze the failure of DCT shift process in mechanical and hydraulic system.Firstly,the fuzzy mathematics involved in fuzzy fault tree analysis is introduced in detail.And then the fault tree analysis is carried out according to the steps of fault tree construction,qualitative analysis and quantitative analysis.Finally,the probability of occurrence of each bottom event is obtained.(3)Select three high-failure bottom events "clutch slip","shift solenoid valve failure" and "oil source low pressure" for detailed analysis,then set up the fault diagnosis strategy and establish the Stateflow diagnostic logic model.Next,establish the DCT and vehicle model based on Simulink,and integrate the diagnostic logic model into the fault diagnosis module.At last,verify the fault diagnosis by simulating the fault source.(4)To sum up the sensor signals in the electronic control system,through the comparative analysis of these signals,the sensor and the electronic control system failure is divided into three levels: serious,moderate and slight,and put forward the disposal strategy;the students of the collaborative project group designed the fault classification and disposal module in the TCU,and then built the HIL test bed,the TCUfault classification and disposal module was verified by manually setting the fault source finally.