When you disengage the clutch, the engine can run without driving the vehicle or operating the accessories. Second, when you start the vehicle, the clutch allows the engine to take up the load of driving the vehicle or accessories gradually and without shock. Clutches are located in the power train between the source of power and the operating unit. Usually, they are placed between the engine and the transmission assembly, as shown in figure 13-1.
Clutches generally transmit power from the clutch-driving member to the driven member by friction.
The driver of the automobile controls the pressure of the springs through use of the clutch. If the driver only applies light pressure, little friction takes place between the two members, which permits the clutch to slip. As the driver increases pressure, friction also increases and less slippage occurs. When the driver s foot releases pressure from the clutch pedal and applies full spring pressure, the driving plate and driven disc move at the same speed. All slipping then stops because of the direct connection between the driving and driven shafts.