Most cars on the road today use a four-stroke piston engine. Explaining how one works, however, can be complicated, and because they’re usually built out of metal it’s tough to see what’s going on. The folks at Warped Perception have come up with a clever solution to this problem by building a cylinder head out of a clear plastic material.
In the video below, the team installs the custom head onto a single-cylinder Briggs & Stratton piston engine and fires it up while filming it in super slow motion. The result is that you can clearly see each step of the process as the engine goes through its cycle.
There are four visible parts in the overhead view of this engine. On the left is the piston, which is the large cylinder that moves up and down. On the right are the intake and exhaust valves, on the top and bottom respectively. Right in between them is the spark plug, which ignites the fuel. This is a four-stroke engine, which means the full cycle has four steps. Step one is the intake valve opening, bringing fuel and air into the chamber while the piston moves down. On step two, the piston moves up, compressing the fuel-air mixture. On step three, the fuel is ignited, and the force of combustion pushes the piston down again. And finally, step four sees the piston move upward, forcing the spent mixture out the open exhaust valve.

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