You might not think much about hydrogen-engines, but they’re actually similar to gas-powered motors in a lot of ways. They both use a four-stroke design for intake, compression, ignition, and exhaust, and both make the same sorts of sound. But, as, Jason Fenske of Engineering Explained shows us, there are some pretty big differences.
The main difference is what sort of exhaust hydrogen engines put out. Instead of toxic NOx gases, hydrogen motors produce water (yes, plain, old water) as the main bi-product of their combustion cycle. Because of the heat also produced by the engine, there are still some harmful NOx emissions, but not nearly as much as a normal gas engine produces.
Because hydrogen is different from gas, the sorts of air-fuel ratios, compression ratios, timing and ignition energies you can run are wildly different from what you’d normally see. For example, you can run an air-fuel ratio as lean as 180:1, and a much higher compression ratio since hydrogen has a higher octane rating. It’s all pretty technical, so if you want to find out everything there is to know, check out Fenske’s video below.
Originally posted on Popular Mechanics