Gm Global Technolgoy Operations, Inc.

Venkatesh Rajagopalan

Nancy Jean Paulus

William John Paulus

Kathryn Mary McCauley

David K Chen

Earl Wayne Lankheet

John J Sterba

Kurt W Wright

David A Thompson

The invention includes the use of a pre-equilibration zone on an exhaust gas sensor to provide catalytic site to catalyze non-reacted components of the exhaust gas prior to the gas sample reaching the sensor's outer electrode. The pre-equilibration zone has microcomposite which preferably includes a precious metal in a porous carrier such as a ceramic oxide. The invention also includes a method of making an exhaust sensor including a pre-equilibration zone, and a method of sampling an exhaust gas by passing the same through a pre-equilibration zone.

Catalytic/ceramic oxide microcomposites for use as exhaust sensor

The invention includes a flat plate exhaust sensor including a flat plate sensing element which is carried by a first ceramic insulator having at its upper end an upwardly extending annular ring. The annular ring defines a disc-shaped recess which is filled with a glass seal. Thus, the glass seal extends from the flat plate sensor to the annular ring of the ceramic insulator. The sensor includes an upper tubular shell which includes at the lower end a leg portion which extends inside an inner wall of a lower tubular shell. The leg portion includes a foot which is bent to match an outwardly extending sloped annular shoulder formed on an upper insulator. The upper insulator is seated on the glass seal. An intermediate gasket is formed by an active metal braze gasket between the foot and the outwardly extending sloped annular shoulder of the upper insulator. An external seal is provided by a braze ring which joins an upper end of the lower tubular shell to the upper tubular shell. The system removed the thermal expansion mismatch problems of prior art glass seal sensors.

Flat plate sensor with a robust package design

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Flint, MI, United States of America

Venkatesh Rajagopalan