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TOD
7
E. CLUTCH COIL
The clutch coil in the TOD is the most important
part. When shifting from to auto mode, the clutch
coil receives the current which in turn is converted
to magnetic force. This magnetic force then
activates the clutch pack assembly which helps in
supplying power to the front wheels.
NOTE
Check the clutch coil for its proper functioning by
checking the resistance value. The coil resistance
should be in the range of 2.375-2.625 Ohms at
25ºC.
6. CLUTCH PACK
Clutch pack helps TOD to shift from 4X2 to Auto
mode. It consists of series of pressure plates and
friction plates which are placed one after the other
in the clutch pack housing gear. When the Auto
mode is activated, pressure plates apply force on
the friction plates which is then transmitted
through the chain drive to the front wheels.
8.3
WORKING OF TOD
The TOD is responsible for distributing torque
between the front and rear axles. The Torque-On-
Demand system is an electrically actuated clutch
mechanism that is used to control the speed
differential of the front and rear outputs of a
transfer case. According to the driving conditions
this system automatically and smoothly delivers
four-wheel drive operation with the help of ECU
controls and patented modulating clutch i.e.
Electromagnetic Clutch.
It receives signals from throttle position sensor
(through Engine ECU)
, ABS sensor
(through ABS/ESP ECU)
for wheel speeds over
CAN. This information is interpreted by the ECU,
which adjusts amount of power delivered to the
front wheels at regular intervals automatically,
when auto mode is selected. It provides effortless
engagement of four-wheel drive at high speeds
(upto 80Kmph)
. Depending on the amount of
slippage detected by the TOD ECU, power
transferred to the Front axle is regulated.
TORQUE DISTRIBUTION
While driving on flat roads or in 4X2 mode
transfer case distributes 8% torque through
front axle and 92% through rear axle.
Based on driving conditions or demand torque,
the torque distribution to the front axle varies
between 8% to 40%.
While driving on an uphill gradient torque
distribution to front axle will be high (i.e. max
40%)