Ways to increase diesel engine efficiency?

[cRiPpLe_rOoStEr]

Just to remind: 2-stroke Diesels are a whole different animal, and they require a supercharger in order to generate enough pressure for scavenging. Their lube system is usually recirculating-type, much like a 4-stroke.

Spark-ignited 2-strokes OTOH rely on the transfer of the intake flow from the crankcase to the cylinder.

Yamaha actually presented a prototype of a 2-stroke Diesel that didn't require a supercharger about 20 years ago, but I don't remember how it was supposed to work.