Abstract: A fuel slurry and engine systems for using the slurry are disclosed. The fuel slurry is a uniform mixture of water and 20 to 50 percent by weight of particulate coal of maximum size equal to 20 microns, the small size promoting complete combustion of the coal and minimizing engine wear due to particles of ash. Engine systems for utilizing the slurry of micronized coal and water are described, the preferred system including a slow-speed, two-stroke turbo-charged diesel engine. Preferred compositions of the fuel slurry are discussed and their behavior in engine systems is analyzed. Also disclosed are techniques for enhancing its ignition.

Abstract: Low pressure steam generated by a solar collector is compressed to raise its temperature and pressure. The compressor is driven by an engine which is, in turn, driven by a combustible fuel. Shaft work produced from the fuel is used directly to drive the compressor. The energy available from the steam is the sum of that resulting from both solar energy and combustion of fuel. The total amount of steam produced per Btu of heat generated by fuel input to the engine is substantially greater than the amount of steam that would be produced directly by combustion of the fuel.

Abstract: A closed vapor cycle engine which uses a trifluoroethanol working fluid improved by the addition of ammonia for corrosion protection. The working fluid may contain water. The improvement improves life and reduces maintenance of the engine.