Ensure a smooth start of the car
This is the primary function of the clutch. Before starting the car, it is natural to start the engine first. When the car starts, it accelerates gradually from a completely static state. If the transmission system (which connects the whole car) is rigidly connected with the engine, the car will suddenly rush forward once the transmission is engaged, but it cannot start. This is because the car has a great inertia from standstill to forward impact, causing a great resistance moment to the engine. Under the effect of this inertial resistance moment, the engine speed drops sharply to the lowest stable speed (generally 300-500RPM) in the instant, and the engine will not work even if it stops, of course, the car will not start.
Therefore, we need the help of the clutch. After the engine is started and before the car starts, the driver first steps down on the clutch pedal to separate the clutch so that the engine and transmission can be separated, then the transmission can be put into gear, and then gradually release the clutch pedal to gradually engage the clutch. During the engagement process, the resistance torque of the engine increases gradually, so the accelerator pedal should be stepped down gradually at the same time, that is, the fuel supply to the engine should be increased gradually, so that the engine speed is always kept at the lowest stable speed without stalling. At the same time, as the engagement tightness of the clutch gradually increases, the torque transmitted by the engine to the driving wheels through the transmission system will gradually increase. When the traction is sufficient to overcome the starting resistance, the car will start moving from a standstill and gradually accelerate.
Achieve smooth shifting
In order to adapt to the constantly changing driving conditions, the transmission system often needs to change different gears to work. To shift a gear transmission, it is generally to move the gear or other gear shifting mechanism to push a gear pair of the original gear out of transmission, and then put the gear pair of the other gear into operation. Before shifting, you must step on the clutch pedal to interrupt the power transmission, so that the meshing pair of the original gear can be disengaged, and at the same time, the speed of the meshing part of the meshing pair of the new gear gradually tends to be synchronized, so that the impact when entering the meshing can be greatly reduced, so as to achieve smooth shifting. 3. Prevent the drive train from overloading
When the vehicle is under emergency braking, if there is no clutch, the engine will sharply reduce the speed due to the rigid connection with the transmission system, so all moving parts will produce a large inertia moment (its value may greatly exceed the maximum torque generated by the engine during normal operation), which will cause a load exceeding its bearing capacity to the transmission system, and damage the parts. With the clutch, this danger can be eliminated by the possible relative movement between the driving part and the driven part of the clutch. Therefore, we need a clutch to limit the maximum torque that the transmission system can bear, so as to ensure safety.
