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:
Jan. 28, 1992
Filed:
May. 17, 1990
John M Bailey, Dunlap, IL (US);
Carey A Towe, Peoria, IL (US);
Scott F Shafer, Peoria, IL (US);
Michael M Blanco, Peoria, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
The service life of conventional glow plugs is extremely short when they are continuously energized at an elevated temperature during engine operation in order to assist ignition of non-autoignitable fuels. Such glow plugs typically fail due to thermal stresses and/or oxidation and corrosion. Herein is disclosed an improved heating element assembly adapted for incorporation in a glow plug. The heating element assembly includes a monolithic sheath having a relatively-thin and generally annular wall defining a blind bore. The heating element assembly further includes a heating device positioned in the blind bore and adapted to emit heat, and a heat transfer device adapted to transfer heat from the heating means to the sheath. The heating device includes a heating filament and a ceramic insulator. THe heating filament is protected against oxidation by being encapsulated in the insulator. The insulator is protected against corrosion by being encapsulated in the sheath. The sheath is formed of a preselected material which is chosen and configured so as to minimize failure of the heating element assembly caused by thermal stresses, oxidation and/or corrosion.