How Clutch Works?

In a car with a manual transmission, you need a clutch assembly to make your car works properly because the engine spins all of the time but the car's wheels don't. In order for a car to stop without stopping the engine, the wheels need to be disconnected from the engine. To do this, then the clutch is installed between the engine and transmission.

Yes, the clutch is a mechanical component that is used to engage and disengage the engine from the transmission. This allows the driver to smoothly switch between gears while driving, and also to stop the car without stalling the engine. The clutch position in car is positioned between the engine and the gearbox (transmission).

The clutch is typically operated by the driver's left foot, using a pedal near the brake pedal. When the driver presses the pedal, it activates a mechanism inside the clutch that separates the engine from the transmission. This allows the gears to be changed without causing the car to lurch or stall. When the pedal is released, the clutch reengages the engine and transmission, allowing the car to move again.

Without a clutch, it would be difficult to drive a manual transmission car smoothly. The clutch allows the driver to control the power and speed of the car by choosing the appropriate gear for the current driving conditions.

Most automotive clutches are dry single-plate clutches with two friction surfaces. No matter the application, the function and purpose of a clutch are to transmit torque from a rotating driving motor (engine) to a transmission. The clutch allows us to smoothly engage the engine to the transmission by controlling the slippage between them.

But before understanding how clutch work, we have to know that major clutch components are used in a car with manual transmission. Here are four major clutch components for an automotive clutch that we know.

Flywheel; Flywheel connected to the rear engine crankshaft and will rotates at the same speed with engine rotation.It's become a source of torque or rotation from the crankshaft through the up and down performance of the piston in the combustion chamber.
Clutch pressure plate (Clutch cover); Clutch cover is attached to the flywheel and has the same speed as engine rotation. The pressure plate is used to press the clutch disc.
Clutch Disc (Friction disc type); Clutch disc is a friction disc placed between the pressure plate and flywheel. It's sandwiched between the flywheel and pressure plate. Clutch disc connected to transmission gear through the transmission's input shaft.
Release bearing; Release bearing translates a linear thrust force from the clutch pedal to the spinning clutch plate assembly mounted to the flywheel.

How does a clutch work?

The car clutch works are divided into two conditions when they engage or disengage the engine power flow to the transmission. It means there are two conditions for clutch works. The first is when the clutch pedal is not pressed, and the second is when the clutch pedal is pressed.

1. When the clutch pedal is not pressed

When the clutch pedal is not pressed, there is no reaction to the clutch assembly. In this position, the clutch disc is in a locked position and rotated along with the engine speed. When the clutch disc rotates, the input shaft transmission is also rotating. Look at the image below for the clutch work when the clutch pedal is not pressed.

The engine power flow from the flywheel > clutch cover > clutch disc > Input shaft transmission.

So, if the clutch pedal is not pressed, the engine power will flow through the clutch assembly and move into the input shaft transmission. The car will not move anywhere if the transmission gears are in a neutral (N) position. But if the gears engage, the car will move forward (1 to 5) or backward (R).

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2. When the clutch pedal is pressed

The release bearing will push the diaphragm spring when the clutch pedal is pressed, pulling the pressure plate away. It creates distance between the clutch disc and pressure plate so the clutch disc will spin freely and not be connected to the engine rotation.

As the clutch disc is not connected with the pressure plate and flywheel, the power flow from the engine to the transmission is disconnected. Look at the image below for the clutch work when the clutch pedal is pressed.

The engine power flow from the flywheel > clutch cover

There is no rotation in the clutch disc (as it disengages from the engine rotation), so the input shaft transmission will not rotate. In this situation, you can more easily shift up or shift down the transmissions gear.

Please note that it's not that the input shaft stops immediately when the clutch is disengaged. It's just that each entity (engine and transmission) is allowed to operate independently of each other at that point. It gives you time to change gears or prepare for a stop.