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:
Dec. 03, 2002
Filed:
Jan. 28, 1997
Donald R. Haefner, Troy, MI (US);
Dennis R. Zitny, Dearborn, MI (US);
David A. Belfi, Royal Oak, MI (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
Transducer housing for mounting in a port in an engine combustion chamber has a metal diaphragm exposed to the combustion gasses. The pressure of the combustion gasses is transferred through an aluminum coupling disc which deflects a simply supported beam member. The beam member is formed of refractory material having epitaxially grown crystalline piezoresistors formed on one surface of the beam member and connected in a bridge circuit and is secured to a ceramic mounting disc. The aluminum coupling disc has a relatively high coefficient of thermal expansion which maintains a preload on the beam member for improved accuracy in spite of the low thermal expansion of the ceramic mounting disc. In an alternate embodiment, an expansion ring made of a material having a relatively high coefficient of thermal expansion is used to support a mounting disc on which the beam member is supported. The high expansion rate of the expansion ring maintains a preload between the beam member and a cup diaphragm by compensating for the relatively low expansion of the ceramic mounting disc.