How Car Engines Work


The 2018 Mercedes-AMG G65 final edition engine delivers 621 hp and 738 lb-ft. of torque. Mercedes AMG

Have you ever opened the hood of your car and wondered what was going on in there? A car engine can look like a big confusing jumble of metal, tubes and wires to the uninitiated.

You might want to know what's going on simply out of curiosity. Or perhaps you are buying a new car, and you hear things like "2.5-liter incline four" and "turbocharged" and "start/stop technology." What does all of that mean?

In this article, we'll discuss the basic idea behind an engine and then go into detail about how all the pieces fit together, what can go wrong and how to increase performance.

The purpose of a gasoline car engine is to convert gasoline into motion so that your car can move. Currently the easiest way to create motion from gasoline is to burn the gasoline inside an engine. Therefore, a car engine is an internal combustion engine — combustion takes place internally.

Two things to note:

  • There are different kinds of internal combustion engines. Diesel engines are one type and gas turbine engines are another. Each has its own advantages and disadvantages.
  • There is also the external combustion engine. The steam engine in old-fashioned trains and steam boats is the best example of an external combustion engine. The fuel (coal, wood, oil) in a steam engine burns outside the engine to create steam, and the steam creates motion inside the engine. Internal combustion is a lot more efficient than external combustion, plus an internal combustion engine is a lot smaller.

Let's look at the internal combustion process in more detail in the next section.

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