RE0F10A_JF011E_RE0F06Arepairpart2变速箱维修手册

JATCO CVT andDaimlerChryslerby Sean BoylePart 2Electronic and ComputerControl Systemsnthe last issue of GEARS,ratio to reduce engine RPM,the stepperwe began looking at themotor (1)moves out,which moves theJATCO Continuously Variableratio control valve (2)out.This allowsTransmission(CVT)being offered withline pressure to enter the primary varia-the 2007 Jeep Compass,Patriot,andtor(4).The additional pressure enteringDodge Caliber.We examined its basicthe primary variator causes the variatorconstruction,and discussed powerflowhalves to squeeze together,causing thethrough the unit.belt to ride toward the outer diameterIn this issue,we're going to look(simulate large gear).Once the primaryinto the electronics and control systemsvariator moves enough to satisfy theused to operate this new transmission,TCM,the ratio control valve movesbeginning with the valve body.back into the hold position.The position of the ratio controlValve Bodyvalve depends on the position of theThe JATCO CVT valve bodyvariator and the stepper motor.Theconsists of pressure sensors,vanatorTCM can alter the ratio by actuatingpressure solenoids,torque converterthe stepper motor,letting the variatorclutch solenoids,and a unique stepperchange until it moves the ratio controlmotor for controlling the pressure splitvalve back into the hold position.Thisbetween the primary and secondaryis possible because these three compo-Figure 1:Ratio Hold Modevariators.nents are linked together mechanically.The stepper motor works (1)inThe fluid release in the secondaryconjunction with the Ratio Controlvariator is controlled by the secondaryValve and (2)as a mechanical link,pressure control solenoid and valve(3).which connects the ratio control valveAs this solenoid is actuated,the pres-and stepper motor to the primary varia-sure trapped in the secondary variatortor (4).(5)can either exhaust,or line pressureThe ratio control valve works incan be directed to it to increase thethree different modes:feed,hold,andclamping load.This is all controlled byvent.These modes detemine the ulti-the TCM.mate position of the variators and con-During the ratio change from lowtrol the resulting ratios (Figure 1).to high,the secondary variator pres-When the TCM is satisfied withsure exhausts to allow the ratio change.the ratio and the position of the varia-Once the change is complete,line pres-tors,the ratio control valve (2)is in thesure is once again directed into thehold position.Line pressure from thesecondary variator to provide clampingpump is fed into the secondary variatorload (Figure 3).(5)to establish the necessary clampingWhen shifting from high to lowforce on the belt (Figure 2).ratio,the TCM moves the stepper motorWhen the TCM wants a higherin,which moves the ratio control valveFigure 2:Low to High RatioGEARS April 2007