Study On Computer Simulation For Front Driving Vehicle With Viscous Limited Slip Differential

Viscous Coupling distinguishes itself in the transmission system for itscharacteristic torque. The principle of viscous coupling is to transfer torque throughplates'shearing viscous liquid, which is called viscous transmission. Limited SlipDifferential(LSD) is a new technique for improving the performance of vehicle. Itget more and more extensive application in the international car field, But in our0country, it develops not much, and doesn't achieve suitable product in practice.This paper makes mainly researches on the application for LSD in vehicle. Thisthesis consists of six chapters:Chapter one is the introduction of this dissertation. Based on large numbers ofrelated books, LSD is detailed discussed in the process of development, structureprinciple, and its application on automobiles. At last, giving the content andmeaning of this dissertation.Chapter two analysis on the torque performance of viscous coupling. The papereduces calculation equations for shearing torque transmitted by viscous couplefrom the research method of two parallel infinite plate's shearing torque producedby the relative turning between them. Afterwards, the paper analyzes the factorsthat influence the characteristic of transferring torque of viscous couple and getsthe calculation model for computing the shear torque of VLSD, with inclusion ofall factors that have effect on the characteristic. This model describes that thedifference of rotate speed of two axle of viscous couple and the workingtemperature of it is the main outside factors influencing the shear torque of VLSD.Chapter three simplifies the heat-transfered process and establishes thecalculation equations to analyze the temperature of viscous couple making use ofmethod of calorifics. Therefore, the instantaneous characteristic of viscous couplecan be described as the function of the two inputing-speed and working time ofviscous couple. That is Tv = T ( Δω , t) Making use of this model, we can analyzethe working property of VLSD with the assistance of computer simulation. Inaddition, this paper brings out a method that can be used to calculate the time andpress that the viscous couple begins to come out torque amplification.Chapter four, with a view of analyze the controllability and stability by virtue ofthe method of system simulation, by analyzing the vehicle in dynamics during itsturning, this model includes 11 degrees of freedom. Including velocity of vehiclec.g.( v), roll angle(φ ), yaw angle(ψ ), wheeling angle(δ ), camber angle(β ), wheelangular velocity( ω1 ,ω 3 ) and slip angle of wheel( α1 ,α 2,α 3 α 4). Making usingof the model established, we can list the dynamics equation;after predigesting, itcan gain the final dynamics equation, which can analyze the controllability andstability. Based on the mathematic model, the thesis establishes a simulation modelfor computer. And we can get the result of controllability and stability on any road.Chapter five is the part of handling stability simulation and analysis. This thesisanalyzes the vehicle's steady state cornering, slaiom steer, and the property of stepresponse. We can ayalyze the influence of the LSD on the vehicle's controllabilityand stability and the matching between them preferably. At last, the paper bringsforward the basic principle of friction disc LSD based on the forth goinganalyzation. In addition, this paper analyzes the variation of controllability andstability of the vehicle assembled with VLSD, and finds that the VLSD hasinfluence on the vehicle's controllability and stability.Chapter six summarizes the main research work, related conclusion and meaningof this dissertation, and lists of the future research fields.The research developed in this paper will promote the study of VLSD in ourcountry more penetrately, and improve the accuracy of the theoretic analyzationand calculation in Viscous Limited Slip Differential (VLSD). At same time, theresearch developed in this paper will make people know more about LSD, and urgethem to the research of this new technique. This research will improve thematching degree between the LSD and vehicle's controllability and stability in thedesign of LSD. Therefore, this research will acceleratethe coming forth of thesuitable domestic LSD product.In addition, the attempt of this paper in analyzingthe vehicle's dynamics by virtue of computer simulation will promote theapplication of this technique in vehicle field.