I wasn't aware of this: With direct fuel injection and a sump-based lubrication system, a two-stroke engine produces air pollution no worse than a four-stroke,

I wasn't aware of this: With direct fuel injection and a sump-based lubrication system, a two-stroke engine produces air pollution no worse than a four-stroke, and it can achieve higher thermodynamic efficiency. https://en.wikipedia.org/wiki/Two-stroke_engine#Applications https://en.wikipedia.org/wiki/Two-stroke_engine#Applications