Abstract: The invention relates to a water-based biodegradable and non-toxic functional fluid for mechanical drives, preferably for use in steam engines. The object of providing such functional fluids for use in mechanical drives, particularly for the hydrodynamic lubrication of plain bearings, preferably for crankshafts of superheated steam engines, having customary bearing play which is not overly precise, is achieved. It should be capable of being used in closed power plant systems also at sump temperatures higher than 120° C., e.g. in the crankcase under a crank shaft, and should be water-based or water-dilutable. According to the invention, this is achieved by addition of a low percentage of polyaspartic acid to water or to water/glycol mixtures, preferably polyaspartic acid having a molar mass of from greater than 1 000 to 10 000 g/mol being used.

Abstract: A pair of sliding elements for machine parts exposed to high-pressure and high-temperature steam, preferably piston-cylinder arrangements for steam engines. The first sliding element is produced from a synthetic, fired but not graphitized carbon material which comprises graphitized carbon black and/or natural graphite as significant filler and whose pores are filled with metal, metal alloy, a ceramic, synthetic resin and/or pitch which has been carbonized, preferably in the form of a piston and/or piston ring. The second sliding element, preferably in the form of a cylinder liner or guide bush, comprising an iron-containing, high-temperature-resistant material which is preferably alloyed with chromium and/or nickel and is provided at least on the surface layer with a nitride layer.

Abstract: The invention relates to a water-based biodegradable and non-toxic functional fluid for mechanical drives, preferably for use in steam engines. The object of providing such functional fluids for use in mechanical drives, particularly for the hydrodynamic lubrication of plain bearings, preferably for crankshafts of superheated steam engines, having customary bearing play which is not overly precise, is achieved. It should be capable of being used in closed power plant systems also at sump temperatures higher than 120° C., e.g. in the crankcase under a crank shaft, and should be water-based or water-dilutable. According to the invention, this is achieved by addition of a low percentage of polyaspartic acid to water or to water/glycol mixtures, preferably polyaspartic acid having a molar mass of from greater than 1,000 to 10,000 g/mol being used.

Abstract: The invention relates to a cylinder piston unit, especially for steam engines with expansion by heat influx, which is constructed as follows: a piston guided in the cylinder element has a displacer, a heating device is mounted on the cylinder element for the stroke area of a non-compacting displacer, the working medium is supplied in a vapour or liquid state in the area of the upper dead point, the expanded working medium is discharged at least in the area of the lower dead point. A pore burner is assigned to the cylinder piston unit in an advantageous mamler. To this end, the invention provides for the heat transfer sections (B, C) of a pore burner (50) which surrounds the cylinder head (43) along part of its height to be arranged at the level of the warm section (41) of the cylinder in the stroke area of the displacer (3) and at the level of the cylinder head (43).