Mazda’s rotary engine is one of those things that you’d be easily forgiven for not understanding unless you were a massive fan of the RX-7 or RX-8. It’s so utterly different than a traditional reciprocating piston engine that it can often help to have some kind of visual aid when explaining it. That’s where this video from Engineering Explained comes in handy.
Jason Fenske — the definitely-older-than-he-looks host of the popular YouTube channel — got his hands on an ingenious 3D-printed model of Mazda’s 13B rotary engine, and in the video that he published on Thursday, he walks us through the unique way that the rotary or Wankel engine turns gasoline into horsepower.
One of the most interesting aspects of the rotary engine design — apart from its somewhat sordid history — is how it manages to do everything that a four-stroke piston engine does, but in a much more compact size and with significantly fewer moving parts.
A rotary engine is a four-stroke engine like you probably have in your car. It uses the same intake, compression, ignition and exhaust process that a piston engine uses, but rather than those events taking place in one place (the cylinder) at different times, it takes place in four different places all at once.
A rotary engine doesn’t have intake or exhaust valves, like a two-stroke piston engine and it also has to have oil injected with the gasoline to lubricate and seal the rotors against the rotor housing just as a two-stroke has to have its oil and fuel mixed. Also like a two-stroke engine, in which every stroke of the engine is a power stroke, every rotation of the rotor features an ignition event, so it can produce an incredible amount of power for its size.
Sadly, because of its need to burn oil and its high fuel consumption, Mazda has stopped developing the rotary. That doesn’t mean that it’s not a fascinating, fun and utterly unique piece of motoring history that should be celebrated. Now, if you’ll excuse us, we’ll be looking at Craigslist for first-generation RX-7’s.