OPERATION
The inner rotor is connected to the engine crankshaft via a oil pump shaft, impeller side of the torque converter, and drive plate; when the inner rotor turns the outer rotor also turns.
Since the number of teeth on the inner rotor and outer rotor are not the same, a space is formed between the inner rotor and outer rotor and its capacity changes as the rotors turn. Oil is drawn in when the capacity is large and is compressed and discharged when the capacity becomes smaller.
The front-rear torque distribution ratio is determined by the of center differential's compound planetary gears and is varied by changing the degree of engagement of the hydraulically operated multi-plate clutch that connects the center differential output elements according to driving conditions and road surface conditions. The torque distribution ratio is calculated using the following equations, which include torque distribution coefficients (determined by number of gear teeth), input torque to the center differential, and torque capacity of the multi-plate clutch as factors.
Scheme 52
Scheme 53
Scheme 54
- When the front wheel speed is higher than the rear wheel speed: TR = 0.543 x T i + T c T F = 0.457 x T i - T c where T R : Rear wheel output torque T i : Input torque to center differential T C : Torque capacity of multi-plate clutch T F : Front wheel output torque 0.543: Coefficient of rear wheel torque determined by number of gear teeth 0.457: Coefficient of front wheel torque determined by number of gear teeth
- When the rear wheel speed is higher than the front wheel speed: T R = 0.543 x T i - T C T F = 0.457 x T i + T C
Scheme 55
< Calculation of front and rear wheel torques>
If the frictional resistance resulting from meshing of the planetary gears and sliding of rotational components are ignored, the torques distributed to the front and rear wheels are expressed by the following equations
T R = [(Z P1 x Z S2 ) divide (Z S1 x Z P2 )] x T i
T F = [1 - (Z P1 x Z S2 ) divide (Z S1 x Z P2 )] x T i
where
Z P1 : Number of teeth of 1st planetary gear
Z P2 : Number of teeth of 2nd planetary gear
Z S1 : Number of teeth of 1st sun gear
Z S2 : Number of teeth of 2nd sun gear
T i : Input torque
If the number of teeth in each component is the same as that assumed in the equations on the previous page, the following ratios are the calculation results of the equations shown above.
T R = 0.543 x T i
T F = 0.457 x T i
As a result, the front-rear torque distribution ratio of the compound planetary gear set without an adjustment by the multi-plate clutch is 45.7 : 54.3.
DESCRIPTION
The electro-hydraulic control system for the transmission and transfer consists of various sensors and switches, TCM, and the control valves including solenoid valves. The system controls the automatic transmission operation, including gear shifting, lockup clutch operation, line pressure, pilot pressure, and gear-shift timing. It also controls the operation of the transfer clutch. The TCM determines vehicle operating conditions from various input signals and controls a total of eight solenoids (front brake solenoid, low coast brake solenoid, input clutch solenoid, high and low reverse clutch solenoid, direct clutch solenoid, lockup solenoid, line pressure solenoid, and transfer solenoid) by sending appropriate signals to them.
Scheme 56
CONTROL WHEN CRUISE CONTROL IN OPERATION
When the cruise control is operating, shifting control is performed by automatically switching to a shifting map that is suitable for cruise control.
CONTROL DESCRIPTION
Engagement of the multi-plate clutch (LSD) in the center differential is controlled according to the torque input to the transfer. It selects a map according to driving conditions and use it as the control basis.
OPERATION OF SPORTS INDICATOR LIGHT
On starting the engine, the SPORTS indicator light illuminates for bulb check and then goes out as shown in the Normal diagram below. If any problem exists, the light continues flashing as shown in the Abnormal diagram below.
