Sleeve Valve Engines (similar technology in terms of piston
lubrication) were built in very large numbers and used successfully
in WWII warplanes. While SVE's demonstrated 10 times lower
cylinder wear rate and established records for fuel efficiency,
they would not meet today's stringent emission standards.
The RLE exploits the design characteristic of the SVE that
lead to reduction of wear and friction, in a way that will
meet those standards. The SVE/RLE characteristic, (interaction
of a rotating liner and reciprocating piston reduces both
friction and wear), is optimized for
friction reduction, resulting in higher friction benefits
than the SVE.