VARIABLE TORQUE DISTRIBUTION CENTER DIFFERENTIAL
The front-rear torque distribution ratio is basically determined by the gear tooth ratio of center differential's compound planetary gears and 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 707
Scheme 708
Scheme 709
Scheme 710
- When the front wheel speed is higher than the rear wheel speed: TR = 0.545 x T i + T C TF = 0.455 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 0.545: Coefficient of rear wheel torque determined by number of gear teeth 0.455: Coefficient of front wheel torque determined by number of gear teeth
- When the rear wheel speed is higher than the front wheel speed: T i = 0.545 x T i - T C T F = 0.455 x T i + T C < 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 = 0.545 x T i T F = 0.455 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 45.5: 54.5.
TORQUE CONVERTER TURBINE SPEED SENSOR
The torque converter turbine speed sensor (output shaft speed sensor) is externally mounted on the transmission case.
The sensor detects the torque converter turbine speed in terms of the rotation speed of the periphery of the high clutch drum coupled to the input shaft, and sends sine wave signals (32 pulses per rotation) to the TCM. The TCM calculates the proportion of the input shaft speed to the vehicle speed and determines whether the shifting is to be made or not.
