The original concept of combustion engines as we understand them dates as far back as the late 1800s. And while they are more or less a solved science today, they definitely didn't start that way.

How boxer engines work, why they’re not just “flat” engines, and a 120-year evolution traced from the 1899 Benz to the latest Porsche and Subaru boxers. Boxer engines feature flat, opposing pistons ...

Any certified gearhead knows that diesel engines do not use spark plugs. But why not? If power in an engine is created by combustion or explosion of flammable liquids, won't a spark plug in a diesel ...