Flexibly making engine block assemblies

Reference Number: N 01-02

Inventors: Rao, V. Durga Nageswar; Rose, Robert A.; Yeager, David A.; Kabat, Daniel M.

Owner: NISTAC

USPTO Link:5566450

Invention Summary

The invention is a method of flexibly manufacturing engine blocks by first bonding extruded tube liners, of a given thickness, to the bore walls of a fixed configuration block, the liner having been coated with a wear-resistant anti-friction coating having a controlled standard thickness, and secondly bonding extruded tube liners of a different wall thickness to the bore walls of another of the fixed configuration blocks, the second liners again having been coated with the same type of wear-resistant anti-friction coating in the same controlled standard thickness.

More particularly the method comprises: (a) making at least first and second engine blocks with commonly sized cylinder bore walls; (b) preparing a set of first liner inserts for the first block from extruded tubing and a set of second liner inserts for the second liner inserts for the second block from other extruding tubing, each set of liner inserts having a different wall thickness resulting from selecting extruded tubing of a different wall thickness in the range of 1-15 mm; (c) implanting the set of first liner inserts into the first block and the set of second liner inserts into the second block, said implanting being with a fit that promotes thermal conductivity across the face between said inserts and bore wall; and (d) applying an adherent anti-friction wear-resistant coating to at least a zone of the interior of each liner insert, said coating being controlled as to uniform thickness, concentricity, and trueness to the operating axes of said engine blocks, said coating being applied either prior to or subsequent to said implanting.

The common sized engine blocks may have identically shaped circular cylindrical bore walls with the variable selection of the wall thickness of said extruded tubing correlating to a cylinder volume displacement change of as much as 100%; or the making of the engine blocks may be with ovoid cross-sectional cylindrical shapes, the selection of the ratio of the major to minor axis of such ovoid cross-sectional shape being in the range of 1.0 to 1.35, the engine blocks having a crankshaft axis with the minor axis of the ovoid shape being parallel to the plane of such crankshaft axis, the extruded tubing having an outer surface complementary to the ovoid shape and having an interior surface the selection of which varies between the circular shape to the ovoid shape, the design variation in the extruded tubing wall correlating to a cylinder volume displacement change of as much as 150%.

To promote ease of fabrication and consistent thermal expansion and thermal conductivity characteristics, the block and liner inserts are both made of aluminum. To promote wear-resistance and lubricant qualities, the coating contains a mixture of hard particles (such as steel, stainless steel, nickel, chromium or vanadium) and solid lubricant particles such as oxides of iron having controlled oxygen, BN, LiF, NaF.sub.2 or a eutectic of LiF/NaF.sub.2.