A differential is a device which is used in vehicles over a few decades and when a vehicle is negotiating a turn, the outside wheel travels a greater distance and turns faster than the inside wheel. The differential is the device transmitting the power to each wheel, allows one wheel to turn faster than the other. It splits the engine torque two ways, allowing each output to spin at a different speed. The differential is found on all modern cars and trucks, and also in many all-wheel-drive (full-time four-wheel-drive) vehicles.

These all-wheel-drive vehicles need a differential between each set of drive wheels, and they need one between the front and the back wheels as well, because the front wheels travel a different distance through a turn than the rear wheels. Part-time four-wheel-drive systems don’t have a differential between the front and rear wheels; instead, they are locked together so that the front and rear wheels have to turn at the same average speed. This is why these vehicles are hard to turn on concrete when the four-wheel-drive system is engaged.

WORKING OF AUTOMATIC DIFFERENTIAL UNIT LOCKING SYSTEM

The proposed mechanism is to lock the differential. By locking the differential the differential is disengaged from the axle. Thus the power is directly transmitted to the axle and hence to the wheels. This will considerably reduce the power loss in some occasions when unwanted loss is happening due to the transmission if power from the shaft to the differential and then to the axle and hence to the wheels. So in mechanism the unwanted power loss in the due course of transmission through the differential is reduced.                   

There are some drawbacks in the existing mechanism and we overcome it in the proposed project. The first is while climbing in steep hills the differential is not really needed as the speed of the vehicle is low. And also there are some transmission loses in the differential. So at this time the unit is locked and the loss is overcome. Then when a heavy truck is struck in a pit or mud it is very difficult to recover the truck as the differential unit cuts the power which is to be transmitted to the wheel struck. 

The unit is disengaged and power is directly given to the axle by pneumatic means and so the recovery is made easier. This is even made use in the vehicle to be driven in the dense forests and even in dessert.

ADVANTAGES OF AUTOMATIC DIFFERENTIAL UNIT LOCKING SYSTEM

• Less Manual force is required to locking the differential unit
• This pneumatic system is also working with the help of air tank
• Time consumption is less
• More efficient system and simple in construction.

DISADVANTAGES OF AUTOMATIC DIFFERENTIAL UNIT LOCKING SYSTEM

• High Initial cost.