Life Is a Highway: How Do Car Engines Work?

If you’re like most drivers, you’ve probably wondered: how do car engines work?

While 83% of Americans drive frequently, it’s safe to assume that many of those drivers, especially Millenials, don’t know how their cars actually work. For most people, a car is just a contraption that gets them from point A to point B.

Although if you drive a car, it’s worth asking the question “how do car engines work?”. Knowing the answer will make you a more educated and informed driver.

So continue reading and we’ll walk you through everything you need to know.

The Internal Combustion Engine

An internal combustion engine is called that because air and fuel combust inside of the engine to make energy. The energy then moves the pistons, which move the car.

An external combustion engine is where fuel is burned outside of the engine. Steam engines work like this. While most people assume steam-powered external combustion engines came first, internal combustion engines actually came before them.

The Anatomy of a Car Engine

An engine is made up of several components. And the engine itself is just one of many performance car parts that’s worth knowing about. We’ll first go over what these components are and then discuss how they work together to make your car move.

Cylinder Block

The cylinder block is the foundation of the engine. It’s called a cylinder block because there are big tubes that are cast into the integrated structure.

These tubes are known as cylinders and this is where the pistons slide down and up. The more cylinders that your engine has, the more power there is.

Combustion Chamber

This combustion chamber is where the air, spark, fuel, and pressure all come together in order to make the small explosions that move the pistons. This is what moves your car.

The chamber is made up of the piston, cylinder, and cylinder head. The cylinder is like the wall of the combustion chamber while the top of the piston is the floor of the chamber. The cylinder head acts like the chamber’s ceiling.

Piston

The piston moves down and up in the cylinder. When fuel ignites in the chamber, the force of the explosion pushes the piston downward. When the piston goes down, it turns the crankshaft.

Crankshaft

The crankshaft is the component that converts the down and up movement of the pistons into a rotary motion that lets the car move.

The crankshaft resides in the crankcase. The crankcase is underneath the cylinder block.

Along the crankshaft are balancing lobes that serve as counterweights. These lobes balance the crankshaft so that the engine doesn’t get damaged from the wobbling that happens when the crankshaft spins.

You’ll also find the main bearings along the crankshaft. These provide a smooth surface between the cylinder block and the crankshaft for the crankshaft to spin.

Valves

There are two kinds of valves, exhaust valves and intake valves. The intake ones bring a mixture of fuel and air into the combustion chamber. This is to make the combustion that will power the engine.

An exhaust valve lets the exhaust gases out of the combustion chamber.

Fuel Injectors

In order to make the combustion that will move the pistons, we’re going to need to put fuel into the cylinders. Today, cars use one of three fuel injection systems to do this: throttle body fuel injection, direct fuel injection, and ported fuel injection.

With direct fuel injection, there is an injector for every cylinder. The injector sprays fuels right into the combustion chamber.

With ported fuel injection, the injector sprays into the intake manifold that’s right outside of the valve, instead of directly into the cylinder. When the valve opens, fuel and air go into the chamber.

When it comes to throttle body fuel injection, there’s only one fuel injector. The air mixes with the fuel in the throttle body and then it’s dispersed via the intake valves to the cylinder.

Sparkplug

There is a sparkplug placed above each cylinder. When it sparks, the compressed air and fuel are ignited and this leads to a little explosion that forces the piston down.

The Four-Stroke Cycle

Now that we understand the main parts of the engine, let’s summarize how they all work together to move the car.

The first step is the intake stroke. During this part of the process, the piston lowers in the cylinder. When it does this, it sucks air into the cylinder via the intake valve while the fuel injector is simultaneously spraying fuel into the cylinder.

Next is the compression stroke. For this step, the valves close and the crankshaft moves the piston back up. This compresses the air-fuel mixture.

During the combustion stroke, the piston reaches the top. The spark plug then sparks, and the fuel-air mixture is ignited. The combustion then forces the piston back down.

In the exhaust stroke, the piston reaches the bottom and the exhaust valve opens up. The piston then comes back up which pushes the exhaust out of the cylinder.

The Importance of Answering “How Do Car Engines Work?”

Hopefully, after reading the above, you now feel that you can adequately answer the question, “how do car engines work?”. Of course, there’s much more to a car than just the engine, but learning how the engine makes the car move is crucial to understanding how cars work in general.

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