Learn how an inline-4 engine works

The inline-4 engine has become a standard powertrain across most automakers’ vehicle lineups, due mostly to its small size and efficiency.

But, have you ever wondered how inline-4 engine actually operates? Thanks to 3D printing technology, and Engineering Explained‘s Jason Fenske’s commentary, we have a better idea as to what happens under the hood.

For this video, the engine happens to be an single overhead cam inline-4 from an older Toyota Tacoma or 4Runner. However, the bases are all largely the same across many inline-4s. The intake manifold and exhaust manifolds are both present on left and right sides of the engine.

What’s intriguing about an inline-4 is how it provides power. The two inner pistons fire at once, and the two outer pistons fire at once, moving in pairs. This is to provide a linear firing interval that lets the operation’s forces balance out. This also makes for a smoother engine with less vibrations transferred. The technical term is “sum of forces,” which includes primary and secondary forces, and it explains why as inline-4 engines increase in displacement, they tend to create more vibrations.

The engines are also usually pretty simple to work on since there’s a single cylinder head. V-type engines and other variants split cylinder banks up and become a little more technical in the process. Of course, each engine style has its own benefits and downfalls. An inline-4 has a higher center of gravity than other engines since the cylinders are placed vertically.

Have a look at how the inline-4 works and allow Jason to do the heavy lifting with technical terms.

Check Also

Why dyno numbers might not be something to boast about

Taking your car to a dyno is often a great way to produce bragging rights, especially after installing various aftermarket modifications. Following the results owners often swear by the figures, but variances in the equipment itself can lead to numerous results that skew the figures themselves. Engineering Explained tackled the subject of dyno testing with...

Say, what can you see? How self-driving cars view roads

When a self-driving car boots up and takes in the world around it, its vision is nothing like what a human driver finds familiar. Instead, a self-driving car uses data collection via radar, cameras, and lidar to "see" the world around it. How can humans begin to understand what the machine sees? Make the human a self-driving car, of course. That's exactly...