Ford Motor Company Limited

Yeshwant P Telang

James C Uy

Leonard G Cordone

A rotor housing for a rotary internal combustion engine is disclosed having a wear-resistant coating system characterized by high temperature hardness stability and controlled porosity to improve the lubricating characteristics of the surface-to-surface engagement with the rotary apex seals. The coating system comprises a self-fused composite of martensitic stainless steel powder and an equally hard powder consisting of a nickel-based alloy. Powder particle size is controlled to render a smoother machined surface and sub-surface porosity. An intermediate transition coating may be used consisting of a composition selected from nickel aluminide, are sprayed nickel, molybdenum, all effective to operate as a bonding intermediate to a supporting aluminum structure. A method of producing the wear-resistant coating system for a rotor housing is disclosed, comprising preparation of an aluminum casting having a supporting epitrochoid end wall, machining a reference, embedment of thermally resistant plugs about certain openings in the end wall, removing a uniform layer of said casting end wall to a predetermined depth, soft grit blasting of the removed surface, coating of the margins about ports in the end wall with an anti-bond material flame spraying the entire end wall with a mixture of martensitic stainless steel and a nickel-based alloy, immersing said coated casting in oil for a predetermined period of time immediately after coating, and grinding off a portion of said coating to the depth of said reference.

Coating for rotary engine rotor housings and method of making

A method of making and the resulting metallurgical product for an apex seal design and/or opposing rubbing surface is disclosed; the seal has ingredients so that it is effective to inherently contain a lubricating film have a retrograde solubility curve so that small additions of chromium can precipitate to achieve a hardening of the matrix, and in some instances an independent graphite lubricant is admixed. A specific example of the composition is a copper-based alloy having 0.1-0.6% chromium and 0.5-1.5% by weight graphite.

Apex seal material

A method is disclosed for fabricating a rotor housing for a rotary internal combustion engine. A conductive mandrel is prepared having an outer surface complimentary to the resultant rotor housing inner wall, the mandrel is provided with an exterior surface smoothness in the range of 4-12 r.m.s. A functional coating of a composite particle wear-resistant material is electrolytically deposited onto the mandrel (acting as a cathode) to form an assembly, the exposed surface of the assembly is controlled to have a roughness characterized by projections no less than 0.030 inches and concentrated in a number no less than 5/cm.sup.2. The assembly is placed in a die-casting machine where a molten metallic medium is cast thereabout forming a casting which is substantially mechanically locked to the assembly. The mandrel is then stripped from the coating to leave the resultant rotor housing. The resultant rotor housing is characterized by wear-resistant inner surface which is almost totally non-porous, its as-deposited surface roughness is at least 24 r.m.s., has a high heat transfer coefficient, is non-brittle and experiences no micro-cracking due to heat checking in service. The composite is economically fabricated and is strongly adherent.

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Grosse Ile, MI, United States of America

Yeshwant P Telang