1. Make sure the car starts smoothly
This is the primary function of the clutch. Before the car starts, it is natural to start the engine. When the car starts, the car gradually accelerates from a completely stationary state. If the drive train (which links the entire car) is rigidly connected to the engine, the car will suddenly move forward as soon as the transmission is in gear, but will not start. This is because when the car moves from standstill to forward, it generates a large inertial force, which causes a large resistance torque to the engine. Under this moment of inertia resistance, the engine's speed drops sharply below the minimum stable speed (generally 300-500 RPM) in an instant, and the engine will stop working and the car will not start.
Therefore, we need the help of a clutch. After the engine starts and before the car starts, the driver first depresses the clutch pedal, disengages the clutch, disengages the engine from the drive train, puts the transmission in gear, and then gradually releases the clutch pedal to gradually engage the clutch. During the engagement process, the engine's blocked torque gradually increases, so you should gradually step on the accelerator pedal at the same time, that is, gradually increase the fuel supply to the engine, so that the engine speed is always maintained at the minimum stable speed without stopping. At the same time, due to the increasing degree of tightness of the clutch engagement, the torque transmitted by the engine to the driving wheels via the driveline gradually increases. When the traction is sufficient to overcome the starting resistance, the car starts to move from standstill and gradually accelerates to ensure that the driveline shifts. Work smoothly.
2. Realize smooth shifting
In the process of driving a car, in order to adapt to changing driving conditions, the drive train often needs to be changed to work in different gears. To realize gear shifting of a gear type transmission, generally, a gear or other gear shifting mechanism is shifted to push out one gear pair of the original gear position for transmission, and then bring the gear pair of the other gear position into operation. Before changing gears, you must step on the clutch pedal to interrupt the power transmission, so that the meshing pair of the original gear can be disengaged. At the same time, the speed of the meshing parts of the meshing pair of the new gear can be gradually synchronized. Reduced to achieve smooth shifting.
3. Prevent overloading of the drive train
When the car is in emergency braking, if there is no clutch, the engine will reduce the speed sharply due to the rigid connection with the drive train, so all moving parts in it will generate a large moment of inertia (its value may greatly exceed that emitted by the engine during normal operation Maximum torque), causing the drive train to exceed its load carrying capacity and cause damage to the machine. With a clutch, this danger can be eliminated by relying on the possible relative movement between the clutch's active and driven parts. Therefore, we need a clutch to limit the maximum torque experienced by the drive train and ensure safety.
