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:
Jun. 06, 1978
Filed:
Nov. 04, 1976
Rainer Corbach, Stuttgart, DT;
Leo Steinke, Waiblingen-Hegnach, DT;
Walter Benedikt, Stuttgart, DT;
Rudolf Jurinke, Schwieberdingen, DT;
Robert Bosch GmbH, Stuttgart, DT;
Abstract
The spark plug center electrode is a composite of a jacket of corrosion resistant material, central filamentary core electrode elements, likewise of corrosion resistant material, and a matrix of thermally and electrically highly conductive material in which the corrosion resistant filamentary elements are embedded, filling the electrode within the outer jacket; in accordance with the present invention, the matrix material is recessed with respect to the jacket and the sparking ends of the corrosion resistant filamentary material to increase lifetime and to provide protection for the electrically and thermally highly conductive material and ensure ignition of even comparatively lean fuel-air mixtures. The electrode has an overall diameter in the order of about 2.4 mm, the recess of the matrix material being between 50 to 500 .mu. m, preferably about 100 to 250 .mu. m; a platinum coating having a thickness of preferably between 40 and 50 .mu. m can be provided to cover the exposed end of the electrode. The recess can be effected by etching selective to the matrix material and not attacking the corrosion resistant jacket and filamentary elements.