The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 01, 1991
Filed:
Oct. 22, 1990
Ernest D Stiles, St. Clair Shores, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
An EGR valve assembly for use in an EGR valve body having a chamber with an inlet and outlet, comprising: (a) a stemmed reciprocable valve controlling flow into said chamber, the stem of said valve being constituted of an iron-based core material (i.e., 300 seeries stainless steel) impregnated at its outer surface with an ingredient (i.e., electroless nickel, ion implanted or chemically deposited nitrides, and electrolytic chromium) that is compatible in sliding contact with ceramic and provides said stem with a hardness at room temperature of at least 60 R.sub.c and a lubricating oxidized passivation layer at a temperatures in excess of 600.degree. C., and (b) a ceramic-based bushing (SiC, Si.sub.3 N.sub.4, Al.sub.2 O.sub.3, ceramic/metal composite) for sealingly guiding the reciprocal movement of said stem.