How Your Car’s Engine Generates Propulsion
As you’re driving, have you ever wondered how your vehicle produces the propulsion energy needed to move your car down the road? It happens as the result of a multi-step process that generates horsepower. This horsepower represents energy that pushes your vehicle whenever you press down on the accelerator.
Inside your engine (under the block), there are a number of cylinders. Each cylinder has a combustion chamber that houses a piston. As you drive, a 4-stroke cycle occurs within the chamber that converts air and fuel into energy. In this article, I’ll describe this cycle in detail. We’ll go through the process, step by step, so you’ll gain an appreciation for the work your engine performs during operation.
Piston At The Top
The first stroke of the cycle begins with the piston positioned at the top of the combustion chamber. It begins to descend toward the bottom of the chamber. Each cylinder has an intake valve and an exhaust valve. As the piston drops, the former opens while the latter closes.
When the intake valve opens, air and fuel enter the chamber. By the time the piston has reached the bottom of its travel, the valve closes, trapping the air-fuel mixture within. This completes the first stroke.
The Piston Rises
The second stroke involves the piston rising within the combustion chamber. Because both valves are tightly closed, the air-fuel mixture is compressed. By the time the piston has reached the top of the cylinder again, the mixture has been compressed to approximately a tenth of its original volume. The resulting pressure cause a marked rise in the temperature. This level of compression is critical for the next stroke of the cycle.
The Spark Plug Ignites The Mix
With the piston at the top of the combustion chamber and the air-fuel mixture compressed to a tenth of its original volume, a spark is needed. A single spark plug is positioned at the top of each cylinder and fires at the beginning of this third stroke. The spark ignites the compressed mixture, creating a mini explosion within the combustion chamber.
The ignition of the air-fuel mixture creates vapors that rapidly expand as the fuel burns. The expansion has sufficient force to push the piston back toward the bottom of the cylinder. As the piston descends, it turns a component called the crankshaft. The crankshaft turns and produces the power needed to move your car.
The cylinders in your vehicle’s engine fire at different times; each firing turns the crankshaft a portion of a full revolution. By the time the crankshaft has completed two turns, all of the cylinders will have fired once.
Out Of The Chamber
When the piston reaches the bottom of the cylinder, the exhaust valve opens. There remains pressure within the combustion chamber; this pressure begins to escape through the open valve as vapors pass from the chamber into the exhaust system. Meanwhile, the piston begins to rise toward the top again, pushing the gases outward through the valve. This occurs with a tremendous amount of force, which explains why your vehicle would make so much noise if it lacked a muffler. With the unburned gases expelled from the cylinder, the exhaust valve closes and the 4-stroke cycle begins anew.
The cycle described above occurs thousands of times each minute. This is the reason it is important that your car’s engine and its accompanying components perform efficiently. A problem with the fuel injectors can lean out the air-fuel mixture and cause misfires. A malfunctioning oxygen sensor can affect the amount of air in the combustion chamber. A bent intake or exhaust valve can cause a compression leak. A lack of oil will lead to overheating.
These circumstances and others will impair the performance of your vehicle’s engine. If you notice problems, have them diagnosed and fixed before they worsen.
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Category: Automotive
Keywords: your car\’s engine, engine propulsion, how an engine works, Kansas cars
