Realize, variable speed and torgue. That is to say, changing thetorque and speed characteristics of the angine to increase itstorque and decrease its speed fo meet the actual drivingregurements of the car, This funetion is achieved throughdifferent gears in the transmission,Realize reversing, The rotation direction of the engine isciockwise wheniewed from front to back and cannot bechanged. in order to achieve reverse driving of the car,reverse gear is set in the transmisslon.