On ICE and Turbines

Internal Combustion Engines (ICE)
Internal Combustion Engine (ICE)

Engine Efficiency

Turbines

Teslaengine.org

Tesla Turbines

Ken Reili Tesla Turbine

Tesla Turbine Wiki

Turbine Engines- no pistons, no lube, better economy

TTengines.com

Oh BTW, Tesla turbines work equally well as engines, drive motors, compressors, or water pumps based upon simple construction and boundary layer effects.

Comparative Efficiency

Carlos Berrera Garza has some interesting ideas with his "gear turbine," but the writeup that I found is somewhere between English and Spanish (not really either one).

Here is a "critic?" site on alternate engine designs:
Halfbakery.com

Jet Engines
Jet Engine