The invention of the internal combustion engine in the 19th century has revolutionized transportation over land, water, and air. Despite their omnipresence in modern day, the operation of an engine may be cryptic. Over the course of this article I’d like to explain the functionality of all the basic engine parts shown in the demonstration below. You can drag it around to see it from other angles:

It’s hard to talk about a mechanical device without visualizing its motion, so many demonstrations in this blog post are animated. By default all animations are enabled, but if you find them distracting, or if you want to save power, you can globally pause them.

An engine like this may seem complicated, but we will build it up from first principles. In fact, we’ll start with a significantly simpler way of generating a rotational motion.