Function of Piston

How Piston Perform Work

 The piston is one of the most critical components of an internal combustion engine. It plays a central role in converting fuel into mechanical energy, driving the machine's operation. The piston moves up and down inside a cylinder, interacting with other parts of the engine to complete a sequence of events known as the four-stroke cycle: intake, compression, power, and exhaust. Let’s dive into each of these steps and how the piston functions.

1. Intake Stroke

During the intake stroke, the piston starts at the top of the cylinder, known as the top dead center (TDC), and moves downward to the bottom dead center (BDC). As it moves down, the intake valve opens, allowing a mixture of air and fuel to enter the cylinder from the intake manifold. The downward movement of the piston creates a vacuum that helps draw this air-fuel mixture into the combustion chamber.

The fuel can either be injected directly into the cylinder (in the case of direct fuel injection) or mixed with air before entering the cylinder (in the case of port fuel injection). At the end of the intake stroke, the intake valve closes, sealing the mixture inside the cylinder.

2. Compression Stroke

Once the intake valve closes, the piston begins its upward movement from BDC back toward TDC. This movement compresses the air-fuel mixture inside the combustion chamber. Compression increases the temperature and pressure of the mixture, making it highly volatile and ready for combustion.

The tighter the compression, the more power can be generated during combustion. However, this process must be precise to avoid knocking, which is premature ignition of the fuel and can damage the engine. The compression stroke is crucial because it prepares the fuel-air mixture for efficient combustion.

3. Power (Combustion) Stroke

When the piston reaches TDC during the compression stroke, a spark plug (in gasoline engines) or compression itself (in diesel engines) ignites the compressed fuel-air mixture. This ignition causes a small explosion, rapidly expanding the gases in the combustion chamber. The force of this explosion pushes the piston downward with tremendous force, transferring energy to the connecting rod attached to the piston.

The connecting rod then transfers this linear movement to the crankshaft, converting the piston's up-and-down motion into the rotational motion necessary to drive the machine's wheels, propellers, or other moving parts. The power stroke is where the engine generates the mechanical power needed for operation.

4. Exhaust Stroke

After the power stroke, the piston reaches BDC and begins moving upward again. During this upward movement, the exhaust valve opens, allowing the burned gases (the byproducts of combustion) to exit the cylinder and be expelled through the exhaust system.

As the piston pushes the exhaust gases out, it reaches TDC again, and the cycle starts over with a new intake stroke. This continuous cycle of intake, compression, combustion, and exhaust powers the engine.

Long-Term Functionality

Over time, pistons experience wear and tear due to the high temperatures and pressures inside the combustion chamber. They are made of durable materials like aluminum alloys to withstand these harsh conditions. Proper lubrication from engine oil is essential to reduce friction between the piston and the cylinder walls, ensuring smooth operation over the engine's lifespan.

Conclusion

In summary, the piston plays a vital role in the internal combustion engine by moving up and down within the cylinder, driving the four-stroke cycle. The piston’s interaction with the fuel-air mixture, valves, and crankshaft enables the engine to convert chemical energy from fuel into mechanical energy. The image provided offers a clear visual of the piston's operation inside the engine, showcasing the critical components involved in each stroke of the cycle.

For More.....