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, 2000
Filed:
Nov. 14, 1997
Daniel Young, Gurnee, IL (US);
Jeffrey Naber, Dearborn, MI (US);
Neil Adams, Novi, MI (US);
Edward Balko, Middletown, NJ (US);
Patrick Blosser, East Windsor, NJ (US);
Linda Hratko, Colonia, NJ (US);
Gerald Koermer, Roseland, NJ (US);
Jie Xue, Buffalo Grove, IL (US);
Adam Moya, Albuquerque, NM (US);
Chowdary Koripella, Albuquerque, NM (US);
Motorola, Inc., Schaumburg, IL (US);
Engelhard Corp., Iselin, NJ (US);
Abstract
A differential calorimetric gas sensor (10) which includes a sensing element (12) having a catalytic layer (14) disposed on a multi-layered substrate (26). Catalytic layer (14) includes an active catalyst region (14a) which oxidizes total combustibles within an exhaust gas stream and a reference catalyst region (14b) which oxidizes selective combustibles within the exhaust gas stream. An electrochemical oxygen source (18) is disposed on an opposite side of multi-layer substrate (26) from sensing element (12). An oxygen sensor cell (170) may be incorporated into electrochemical oxygen source (18). The multi-layered substrate (26) includes a plurality of overlaying insulating layers in which an intermediate layer (60) and a bottom layer (64) support primary heaters (58, 62), and in which another intermediate layer (52) supports compensation heaters (50a, 50b). The primary heaters (58, 62) function to maintain sensor (10) at a substantially constant temperature, while the compensation heaters (50a, 50b) function to restore temperature deviations determined by temperature-sensitive elements (46a, 46b) located on an inner layer (48) overlaying the compensation heaters (50a, 50b) resulting from the catalytic reactions taking place at the surfaces (34a, 34b) of the catalyst regions (14a, 14b). The control circuitry (300) operates to control the primary heater (58, 62) and the compensation heaters (50a, 50b), as well as to minimize the response variations of the temperature-sensitive elements (46a, 46b).