For most people, a car is something they fill up with gasoline and that gets them from point A to point B. But have you ever stopped and thought: how does it actually do that? What makes it move? If you haven’t already used a car as your daily driver, then the magic of the combustion engine, the thing that makes noise under the hood is a true marvel. But how does a gasoline car engine actually work?
More specifically, an internal combustion is a heat by converting the energy from the heat of burning gasoline into torque. This torque is applied to the wheels to get the car moving.
Where Does The Engine Power Come From?
What propels these pistons up and down are the tiny, controlled explosions that take place every seconds, created by the fuel and oxygen combination and igniting the mixture. The heat and expanding gasoline from this explosion push the piston down the cylinder. Almost all of today’s internal combustion engines, to keep it easy, we’ll focus on gasoline engines here, are of the four-stroke variety. In addition to the combustion stroke, which pushes the piston down from the top of the cylinder, there are three other strokes: intake, compression and exhaust.
Engines need to burn fuel. During the intake stroke, the valves open to allow the piston to act as a syringe as it moves down, drawing ambient air through the engine’s intake. When the piston reaches the bottom of its stroke, the intake valves close, sealing the cylinder for the compression stroke, which is in the opposite way to the intake stroke. The upward movement of the piston compresses the intake charge.
In today’s most advanced engines, gasoline is injected into the cylinders near the top of the compression stroke. Other engines premix the air and fuel during the intake stroke. In both cases, spark plugs ignite the air and fuel just before the piston reaches the top of its travel. The resulting expansion of the hot, burning gases pushes the piston in the opposite way during the combustion stroke. This is the hub that gets your car’s wheels rolling, just like pushing down the pedals on a bike. When the combustion stroke reaches bottom, the exhaust valves open to allow the combustion gases to be pumped out of the engine as the piston comes back up. When the exhaust is expelled it continues through the car’s exhaust before exiting the rear of the vehicle and the exhaust valves close at top and the whole procedure begins again.
In a cylinder car engine, the cycles of the individual cylinders are staggered and evenly distributed so that the combustion strokes do not take place simultaneously and the engine is as smooth as possible. But not all engines are created equal. They come in many shapes and sizes. Most engines arrange their cylinders in a straight line, such as an in-line four model or mix two banks of cylinders in a V. Engines are also categorized by their size or displacement, which is the complete volume of a cylinder.
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