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How do Engine Pistons Work

Everybody owns a car nowadays, but only a few people know how a car’s engine functions. Many believe that the most important component of a car engine is the cylinder, but what they don’t know is without engine pistons it can almost be impossible for a car to function. Engine pistons are cylindrical pieces of metal that move up and down the cylinder to generate the force needed to power a car.


In order to understand how engine pistons work, we need to take a look at the four important cycles each piston runs through. For those of you who don’t know, all engines use what is called a four-stroke combustion cycle (this may vary depending on the engine size), which means that each cylinder requires four pumped strokes in order to generate power in the engine. To understand more, let’s take a look at each cycle stroke in more depth:


Intake Stroke

The piston descents on the intake stroke from the top of the cylinder to the bottom. This repeated motion creates a pressure that is responsible for combining air and fuel into the cylinder. This mixture of air and fuel is then forced into the cylinders, which is known as the “Intake Port” after which the intake valve closes. This is the first process that occurs in your engine when you start your car.


Compression Stroke

As soon as the intake valve closes, the piston returns back to the top of the cylinder. This is when the compression stroke, as the name implies compresses the air and fuel mixture into the combustion chamber of your engine in the cylinder head. During this process, the temperature of air and fuel increases significantly, thus creating the energy needed to power your car engine.


Power Stroke

Once again when the piston reaches the top of the cylinder, the compressed air and fuel mixture is ignited in the power stroke via a spark plug (a component that supplies the spark at the right moment for your car to function properly).


Once the spark is released, the air and fuel mixture creates a small explosion, which then forces the piston back down to the cylinder shaft. The spark plug plays an imperative role in this process, hence if the spark doesn’t occur, your car won’t start.


Exhaust Stroke

The exhaust stroke, as the name implies is responsible for allowing the wasted air and fuel mix caused from the ignition to leave the engine. The air and fuel mix is generally moved down through the pressure of the explosion to the catalytic converter and then to the muffler. The exhaust stroke also prevents the fuel and air mixture from leaking into the pump during compression and combustion. Regardless, once the stroke cycle is complete, the piston returns again to the top of the cylinder.


This process is then repeated continuously by each of the strokes, thus powering the car engine. The speed of this process of strokes determines the overall speed of the vehicle. This means the more you accelerate the more air and fuel flows through the engine, thus the pistons move faster which in turn increases the speed of your vehicle.

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