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.