Main Functions of Automotive Transmission

Deceleration and speed change

When traction acting on the driving wheel is sufficient to overcome the resistance from the outside force to the car, the car is able to start and normal driving. If the engine directly effect on driving wheels, that's the maximum speed of the engine, and the car will reach a very high speed. A car of high and constant speed is very unrealistic, and possibly because the corresponding traction is too small, the car will not start, or can not uphill.

The primary function of the automotive transmission is to change the transmission ratio, and expand the range of variation of torque and rotational speed of the drive wheels, to accommodate the constantly changing driving conditions, to achieve the goal of slowing down and shifting, while the engine is working in a favorable conditions (higher power and lower fuel consumption).

Reverse driving

The car needs to travel backward in some cases. However, the piston internal combustion engine cannot counter-rotating, so the transmission working together with internal combustion engine should ensure the reverse rotation of the drive wheels under the situation that the engine still keeps the direction. The general structure is to add reverse gear (speed reducing gear pair with intermediate gear) in the transmission.