Quickly activatable structure of gas sensor element

Abstract

A quickly activatable structure of a gas sensor element includes a measurement gas electrode, a reference gas electrode, a solid electrolyte layer to which the measurement and reference gas electrodes are affixed, and a heater. The heater has a heating element to heat the solid electrolyte layer. A reference gas chamber is defined between the solid electrolyte member and the heater and has a length made up of a first chamber and a second chamber. The first chamber is located in a heating area in which the heating element is disposed. The second chamber is located in a non-heating area and has at least a portion which is greater in volume per unit length of the reference gas chamber than the first chamber, thereby decreasing the dissipation of thermal energy to the non-heating area, which enhances the thermal transfer from the heating element to the solid electrolyte member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detailed description given hereinbelow and from the accompanying drawings of the preferred embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments but are for the purpose of explanation and understanding only.

In the drawings:

FIG. 1 is a partially longitudinal sectional view which shows the layout of a heater in a gas sensor element according to the first embodiment of the invention;

FIG. 2 is a transverse sectional view taken along the line A-A in FIG. 1;

FIG. 3 is a transverse sectional view taken along the line B-B in FIG. 1;

FIG. 4 is a longitudinal sectional view which shows a reference gas chamber formed in the gas sensor element of FIG. 1;

FIG. 5 is an exploded view which shows the gas sensor element of FIG. 1;

FIG. 6( a) is a top view which shows the gas sensor element of FIG. 5;

FIG. 6( b) is a longitudinal sectional view which shows the layout of a heater in the gas sensor element of FIG. 5;

FIG. 6( c) is a side view of the gas sensor element of FIG. 5;

FIG. 7( a) is a longitudinal sectional view which shows a reference gas chamber form in a gas sensor element according to the second embodiment of the invention;

FIG. 7( b) is a side view of the gas sensor element of FIG. 7(a);

FIG. 8 is a transverse sectional view taken along the line A-A in FIG. 7(a);

FIG. 9 is a transverse sectional view taken along the line B-B in FIG. 7(b);

FIG. 10 is a longitudinal sectional view which shows a reference gas chamber form in a gas sensor element according to the third embodiment of the invention;

FIG. 11 is a transverse sectional view taken along the line A-A in FIG. 10;

FIG. 12 is a transverse sectional view taken along the line B-B in FIG. 10;

FIG. 13 is a longitudinal sectional view which shows a reference gas chamber form in a gas sensor element according to the fourth embodiment of the invention;

FIG. 14 is a transverse sectional view taken along the line A-A in FIG. 13;

FIG. 15 is a transverse sectional view taken along the line B-B in FIG. 13;

FIG. 16 is a longitudinal sectional view which shows a reference gas chamber form in a gas sensor element according to the fifth embodiment of the invention;

FIG. 17 is a transverse sectional view taken along the line A-A in FIG. 16;

FIG. 18 is a transverse sectional view taken along the line B-B in FIG. 16;

FIG. 19 is a longitudinal sectional view which shows a reference gas chamber form in a gas sensor element according to the sixth embodiment of the invention;

FIG. 20 is a transverse sectional view taken along the line A-A in FIG. 19;

FIG. 21 is a transverse sectional view taken along the line B-B in FIG. 19;

FIG. 22( a) is a longitudinal sectional view which shows a reference gas chamber form in a gas sensor element according to the seventh embodiment of the invention;

FIG. 22( b) is a side view of the gas sensor element of FIG. 22(a);

FIG. 23 is a transverse sectional view taken along the line A-A in FIG. 22(a);

FIG. 24 is a transverse sectional view taken along the line B-B in FIG. 22(b);

FIG. 25 is a transverse sectional view taken along the line A-A in FIG. 27;

FIG. 26 is a transverse sectional view taken along the line B-B in FIG. 27;

FIG. 27 is a top view which shows a gas sensor element according to the eighth embodiment of the invention;

FIG. 28 is a transverse sectional view which shows a top end portion of a gas sensor element according to the ninth embodiment of the invention;

FIG. 29 is perspective view which shows how to make reference gas chambers in green sheet according to the tenth embodiment of the invention;

FIG. 30 is a partially side view of FIG. 29;

FIG. 31 is a transverse sectional view which shows how to make reference gas chambers in green sheet according to the eleventh embodiment of the invention;

FIGS. 32( a), 32(b), and 32(c) are longitudinal sectional views which show different types of test samples used to measure the time required for activating the samples;

FIGS. 33( a) and 33(b) are longitudinal sectional views which show different types of test samples used to measure the time required for activating the samples;

FIG. 34 is a transverse sectional view which shows a top end portion of a conventional gas sensor element; and

FIG. 35 is a transverse sectional view which shows a base end portion of the gas sensor of FIG. 34.

Claims

1. A gas sensor element comprising: an oxygen ion conductive solid electrolyte member;a measurement gas electrode which is affixed to one of opposed surfaces of said solid electrolyte member and exposed to a gas to be measured;a reference gas electrode affixed to the other of the opposed surfaces of said solid electrolyte member;a heater equipped with a heating element working to heat said solid electrolyte member; anda reference gas chamber defined between said solid electrolyte member and said heater, said reference gas chamber being filled with a reference gas to which said reference gas electrode is exposed, said reference gas chamber having a length made up of a first chamber and a second chamber, the first chamber being located in a heating area in which the heating element of said heater is disposed, the second chamber being located in a non-heating area and having at least a portion which is greater in volume per unit length of said reference gas chamber than the first chamber.

2. A gas sensor element as set forth in claim 1, wherein the first chamber has a maximum transverse sectional area which is smaller than that of the second chamber.

3. A gas sensor element as set forth in claim 1, wherein an average of transverse sectional areas along a length of the first chamber is smaller than that of the second chamber.

4. A gas sensor element comprising: an oxygen ion conductive solid electrolyte member;a measurement gas electrode which is affixed to one of opposed surfaces of said solid electrolyte member and exposed to a gas to be measured;a reference gas electrode affixed to the other of the opposed surfaces of said solid electrolyte member;a heater equipped with a heating element working to heat said solid electrolyte member; anda chamber defined between said solid electrolyte member and said heater, said chamber being located in a non-heating area which lies outside a heating area in which the heating element of said heater is disposed.

5. A gas sensor element as set forth in claim 4, further comprising a pumping reference function working to feed a reference gas to said reference gas electrode through said solid electrolyte member.