HEXA

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%)