JP2020003471A - Gas sensor - Google Patents

Abstract

To provide a gas sensor with which it is possible to enhance heat transfer performance of a sensor element and achieve early activation of the sensor element .SOLUTION: A sensor element 2 of a gas sensor 1 comprises a solid electrolyte 31, a detection electrode 311, a reference electrode 312, a first insulator 33A, a second insulator 33B, a gas chamber 35, a reference gas duct 36, a heating element 34, and a heat transfer member 38, etc. A part of a heating part 341 of the heating element 34 is arranged at a position where the detection electrode 311 and the reference electrode 312 overlap with each other in a laminate direction D. The heat transfer member 38 is formed with a compact material of metal oxide that does not pass gas G to be detected. The heat transfer member 38 is held, in a part of the gas chamber 35, between the detection electrode 311 and the first insulator 33A where the heating element 34 is buried. The heat transfer member 38 promotes heat transfer from the heating part 341 to the solid electrolyte 31, the detection electrode 311 and the reference electrode 312.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a gas sensor including a plate-shaped sensor element.

  The gas sensor is disposed, for example, in an exhaust pipe of an internal combustion engine, and is used to detect a concentration of a specific gas component such as an oxygen concentration in the detection target gas, using exhaust gas flowing through the exhaust pipe as a detection target gas. The sensor element of the gas sensor has a solid electrolyte body having oxygen ion conductivity, and a detection electrode and a reference electrode provided at opposing positions on both surfaces of the solid electrolyte body. In addition, a heating element that generates heat when energized is embedded in the insulator laminated on the solid electrolyte body. The heating part of the heating element is arranged at a position facing the electrode, and the heat generated from the heating part heats the detection electrode, the reference electrode, and the portion of the solid electrolyte body sandwiched between the electrodes to the active temperature. are doing.

  For example, in the oxygen sensor element of Patent Document 1, a detection electrode and a reference electrode are provided at opposing positions on both sides of a plate-shaped base made of a ceramic solid electrolyte. It is described that an air introduction hole to be introduced is formed. It is described that the air introduction hole is filled with a porous ceramic.

JP 2003-344350 A

  A sensor element of a gas sensor for detecting an air-fuel ratio or the like contains a detection electrode provided on a solid electrolyte body, and is provided with a gas chamber for supplying a detection target gas such as exhaust gas to the detection electrode. In some cases, the sensor element accommodates a reference electrode provided on the solid electrolyte body, and is provided with a reference gas duct for supplying a reference gas such as air to the reference electrode.

  Gas spaces such as gas chambers and reference gas ducts are formed as cavities in the sensor element. Therefore, this gas space is a portion that suppresses heat transfer from the heat generating portion of the heat generating element to the solid electrolyte member and each electrode. Therefore, in order to activate the sensor element at an early stage, a device for promoting heat transfer in the gas space is required.

  In the oxygen sensor element of Patent Literature 1, it is considered that the heat transfer from the heat generating portion to the solid electrolyte member and each electrode is improved by filling the air introduction hole with the porous ceramic. However, the porous ceramic is filled in the entire air introduction hole, and is premised on allowing the air to pass through. Therefore, it is not possible to sufficiently promote the heat transfer in the air inlet.

  The present invention has been made in view of such a problem, and has been achieved in order to provide a gas sensor capable of improving the heat conductivity of a sensor element and quickly activating the sensor element.

One embodiment of the present invention relates to a gas sensor (1) including a plate-shaped sensor element (2),
The sensor element includes:
A solid electrolyte body (31) having oxygen ion conductivity;
A pair of electrodes (311, 312) provided on the surface of the solid electrolyte body;
An insulator (33A, 33B) laminated on the solid electrolyte body;
A gas space formed between the insulator at a position adjacent to the solid electrolyte body and accommodating one of the pair of electrodes and introducing a detection target gas (G) or a reference gas (A) ( 35, 36),
A heating section (341) that generates heat when energized and is disposed at a position where at least a part thereof overlaps the pair of electrodes in the stacking direction (D) of the solid electrolyte body and the insulator, and a pair of heating sections connected to the heating section. A heating element (34) having a lead portion (342) and embedded in the insulator forming the gas space;
The detection target gas is not permeated, and formed of a dense material of a metal oxide, and in a part of the gas space, between the insulator and the electrode in which the heating element is embedded, or the heating element is A heat transfer member sandwiched between the buried insulator, the electrode, and the solid electrolyte body, and for promoting heat transfer from the heat generating portion to the solid electrolyte body and the pair of electrodes; And a gas sensor comprising:

Another embodiment of the present invention provides a gas sensor (1) including a long plate-shaped sensor element (2).
The sensor element includes:
A solid electrolyte body (31) having oxygen ion conductivity;
A detection electrode (311) provided on the first main surface (301) of the solid electrolyte body, which is exposed to the gas to be detected (G), at a position on the tip side in the longitudinal direction (L) of the sensor element;
A reference electrode (312), which is a second main surface (302) of the solid electrolyte body exposed to a reference gas (A) and is provided at a position on the distal end side in the long direction;
A first insulator (33A) laminated on the first main surface of the solid electrolyte body;
A heat-generating portion (341) which is arranged at a position where at least a part thereof overlaps the detection electrode and the reference electrode in the stacking direction (D) of the solid electrolyte body and the first insulator, and which generates heat by energization; A heating element (34) having a pair of leads (342) connected to a rear end side of the portion in the long direction and embedded in the first insulator;
A gas chamber (35) formed in a position of the first insulator adjacent to the first main surface of the solid electrolyte body and accommodating the detection electrode;
A diffusion resistance section (32) provided on the first insulator in communication with the gas chamber, for introducing the gas to be detected into the gas chamber at a predetermined diffusion rate;
A second insulator (33B) laminated on the second main surface of the solid electrolyte body;
A position adjacent to the second main surface of the solid electrolyte body in the second insulator, formed from a rear end opening (360) in the elongated direction to a position for accommodating the reference electrode; and A reference gas duct (36) through which the reference gas is introduced from the rear end opening;
The detection target gas is not permeated and is formed of a dense material of a metal oxide, and in a part of the gas chamber, between the first insulator and the detection electrode or between the first insulator and the detection. A heat transfer member (38) sandwiched between an electrode and the solid electrolyte body, and for promoting heat transfer from the heat generating portion to the solid electrolyte body, the detection electrode, and the reference electrode. In the gas sensor.

Still another embodiment of the present invention relates to a gas sensor (1) including a long plate-shaped sensor element (2),
The sensor element includes:
It has oxygen ion conductivity and has a first pump electrode (311A) and a second pump electrode (311B) provided at positions facing each other at the tip side position in the longitudinal direction (L) of the sensor element. 1 solid electrolyte body (31A);
A detection electrode (312A) that is disposed to face the first solid electrolyte body, has oxygen ion conductivity, and is provided at a position facing each other at a position on the distal end side in the longitudinal direction (L) of the sensor element; And a second solid electrolyte body (31B) having a reference electrode (312B) and
A first insulator (33C) laminated on a main surface of the first solid electrolyte body on which the first pump electrode is provided;
A second insulator (33D) sandwiched between a main surface of the first solid electrolyte body on which the second pump electrode is provided and a main surface of the second solid electrolyte body on which the detection electrode is provided; ,
A third insulator (33E) laminated on a main surface of the second solid electrolyte body on which the reference electrode is provided;
A heat generating portion (341) that generates heat by energization and is disposed at a position where at least a part thereof overlaps with each of the electrodes in a stacking direction (D) of each of the solid electrolyte bodies and each of the insulators; A heating element (34) having a pair of leads (342) connected to the rear end side in the longitudinal direction and embedded in the third insulator;
A gas chamber (35) formed so as to be surrounded by the first solid electrolyte body, the second solid electrolyte body, and the second insulator, and formed at a position accommodating the second pump electrode and the detection electrode;
A diffusion resistance section (32) provided on the second insulator in communication with the gas chamber, for introducing a gas to be detected into the gas chamber at a predetermined diffusion rate;
The detection target gas is not permeated, and is formed of a dense material of metal oxide, and in a part of the gas chamber, between the second pump electrode and the detection electrode, or between the second pump electrode and the second pump electrode. 1 is sandwiched between the solid electrolyte body, the detection electrode, and the second solid electrolyte body, and promotes heat transfer from the heat generating portion to the first solid electrolyte body, the first pump electrode, and the second pump electrode. And a heat transfer member (38).

(One Embodiment of Gas Sensor)
In the gas sensor according to the one aspect, the heating element is embedded in the insulator forming the gas space, and a part of the gas space is between the insulator and the electrode in which the heating element is embedded or the heating element is embedded. A heat transfer member is sandwiched between the insulator and the electrode and the solid electrolyte body. The heat transfer member is formed of a dense metal oxide material that does not allow the gas to be detected to permeate, and promotes heat transfer from the heat generating portion of the heat generating element to the solid electrolyte member and each electrode.

  When the solid electrolyte member and each electrode are heated by the heat generated by the heat generating portion, the heat in the heat generating portion is transmitted to the solid electrolyte member and each electrode via the insulator, and also through the heat transfer member. And transmitted to each electrode. At this time, heat is transferred from the heat generating portion to the solid electrolyte member and each electrode via the insulator so as to bypass the gas space, and from the heat generating portion to the solid electrolyte member and each electrode via the heat transfer member. The heat is transferred straight.

  Thereby, the heat conductivity from the heat generating portion to the solid electrolyte body and each electrode, in other words, the heat conductivity of the sensor element can be increased. Further, at the time of starting the gas sensor or the like, the time for heating the sensor element to a temperature at which the conductivity of oxygen ions is activated by the heat generated by the heat generating portion can be reduced.

  Therefore, according to the gas sensor of one aspect, the heat conductivity of the sensor element can be enhanced, and the sensor element can be activated early.

  Further, when the heat transfer member is sandwiched between the electrode in which the heating element is embedded and the electrode and the solid electrolyte member, the area covered with the electrode by the heat transfer member is reduced, so that the sensor element is used. It is possible to suppress an increase in electric resistance when performing gas detection. Further, in this case, a part of the heat transfer member is joined to the solid electrolyte body, and the joining strength in the sensor element can be increased. Also in this case, the heat transfer member can also enhance the heat transfer of the sensor element. The same applies to the gas sensor according to another aspect and the gas sensor according to still another aspect.

(Gas Sensor of Another Embodiment)
In the gas sensor according to the other aspect, when the sensor element has a gas chamber and a reference gas duct, the heating element is arranged on the first insulator forming the gas chamber, and the heat transfer member is arranged on a part of the gas chamber. ing. By disposing the heating element on the first insulator, the heating section of the heating element can be disposed closer to the solid electrolyte member and each electrode. Further, since the heat transfer member is disposed in a part of the gas chamber, the heat of the heat generating portion can be transferred to the solid electrolyte body and each electrode via the heat transfer member in the gas chamber. Thereby, when the sensor element has the gas chamber and the reference gas duct, the heat of the heat generating portion of the heat generating element can be easily transmitted to the solid electrolyte member and each electrode via the heat transfer member.

  Further, when the heat transfer member is sandwiched between the first insulator, the detection electrode, and the solid electrolyte member, similarly to the gas sensor of one embodiment, the increase in electric resistance is suppressed and the bonding strength of the sensor element is reduced. The effect of improvement is obtained.

(Gas Sensor of Still Another Embodiment)
In the gas sensor according to still another aspect, when the sensor element has a plurality of solid electrolyte bodies and gas chambers, the heat transfer member is disposed in a part of the gas chamber located between the solid electrolyte bodies. Then, heat transfer from the heating element to the first solid electrolyte element, the first pump electrode, and the second pump electrode of the two solid electrolyte elements that are located farther from the third insulator in which the heating element is embedded. Can be improved.

  Further, when the heat transfer member is sandwiched between the second pump electrode and the first solid electrolyte member and the detection electrode and the second solid electrolyte member, the electric resistance increases similarly to the gas sensor of one embodiment. And the effect of improving the bonding strength of the sensor element can be obtained.

  Note that the reference numerals in parentheses of the components shown in the respective aspects of the present invention indicate the correspondence with the reference numerals in the drawings in the embodiments, but the components are not limited only to the contents of the embodiments.

FIG. 2 is a cross-sectional view illustrating the gas sensor according to the first embodiment. FIG. 2 is a perspective view showing the sensor element before stacking according to the first embodiment. FIG. 2 is a cross-sectional view illustrating the sensor element according to the first embodiment. FIG. 4 is a cross-sectional view of the sensor element according to the first embodiment, taken along line IV-IV of FIG. 3. FIG. 3 is an explanatory diagram illustrating an arrangement relationship among a detection electrode, a heat generating portion, and a heat transfer member in the sensor element according to the first embodiment. FIG. 4 is an explanatory diagram showing an arrangement relationship among a detection electrode, a heat generating portion, and a heat transfer member in another sensor element according to the first embodiment. FIG. 4 is an explanatory diagram showing an arrangement relationship among a detection electrode, a heat generating portion, and a heat transfer member in another sensor element according to the first embodiment. FIG. 6 is a cross-sectional view illustrating a sensor element according to the second embodiment. FIG. 9 is a cross-sectional view of the sensor element according to the second embodiment, taken along the line IX-IX in FIG. 8. FIG. 9 is an explanatory diagram showing an arrangement relationship of a detection electrode, a heat generating portion, and a heat transfer member in a sensor element when a heat generating portion is formed to meander in a longitudinal direction according to a third embodiment. FIG. 11 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 10 according to the third embodiment. FIG. 11 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 10 according to the third embodiment. FIG. 11 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 10 according to the third embodiment. FIG. 11 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 10 according to the third embodiment. FIG. 9 is an explanatory diagram showing the arrangement relationship of a detection electrode, a heat generating portion, and a heat transfer member in a sensor element when a heat generating portion is formed to meander in a width direction according to a third embodiment. FIG. 16 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 15 according to the third embodiment. FIG. 16 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 15 according to the third embodiment. FIG. 16 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 15 according to the third embodiment. FIG. 13 is an explanatory diagram showing another arrangement relationship of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element when the heat generating portion is formed without meandering according to the third embodiment. FIG. 20 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 19 according to the third embodiment. FIG. 20 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 19 according to the third embodiment. FIG. 20 is an explanatory diagram showing another arrangement relation of the detection electrode, the heat generating portion, and the heat transfer member in the sensor element in the case of FIG. 19 according to the third embodiment. FIG. 14 is a cross-sectional view illustrating a sensor element according to the fourth embodiment. FIG. 24 is a cross-sectional view along XXIV-XXIV of FIG. 23 illustrating a sensor element according to the fourth embodiment. FIG. 4 is a view corresponding to a cross section taken along line IV-IV of FIG. 3, showing a sensor element according to a fifth embodiment. FIG. 13 is an explanatory diagram illustrating an arrangement relationship between a detection electrode and a heat transfer member according to the fifth embodiment. 13 is a graph showing a relationship between an overlap ratio and an electric resistance ratio according to the fifth embodiment. FIG. 4 is an IV-IV cross-sectional equivalent view of FIG. 3 showing a sensor element according to a sixth embodiment. FIG. 13 is an explanatory diagram illustrating an arrangement relationship between a detection electrode and a heat transfer member according to a seventh embodiment. 14 is a graph showing a relationship between a distance from a distal end to a proximal end of a detection electrode and a cumulative current according to the seventh embodiment. 13 is a graph showing a relationship between a distance from a distal end to a proximal side of a detection electrode and a response time according to the seventh embodiment. FIG. 14 is a cross-sectional view showing a part of another sensor element according to the seventh embodiment.

A preferred embodiment of the above-described gas sensor will be described with reference to the drawings.
<First embodiment>
As shown in FIGS. 1 and 3, the gas sensor 1 of the present embodiment includes a long plate-shaped sensor element 2 for detecting gas. The sensor element 2 includes a solid electrolyte body 31, a detection electrode 311 and a reference electrode 312 as a pair of electrodes, a first insulator 33A, a second insulator 33B, a gas chamber 35 and a reference gas duct 36 as a gas space, and a heating element 34. , A heat transfer member 38.

As shown in FIG. 2 to FIG. 4, the solid electrolyte member 31 has oxygen ion (O ²⁻ ) conductivity. The detection electrode 311 and the reference electrode 312 are provided at positions opposed to each other on a first main surface 301 and a second main surface 302 as surfaces of the solid electrolyte body 31. The first insulator 33A is stacked on the first main surface 301 of the solid electrolyte body 31, and the second insulator 33B is stacked on the second main surface 302 of the solid electrolyte body 31.

  The gas chamber 35 is formed at a position adjacent to the first main surface 301 of the solid electrolyte body 31 so as to be surrounded by the first insulator 33 </ b> A, and also accommodates the detection electrode 311 and introduces the detection target gas G. It is. The reference gas duct 36 is formed at a position adjacent to the second main surface 302 of the solid electrolyte body 31 so as to be surrounded by the second insulator 33B, and is a portion where the reference electrode 312 is accommodated and the reference gas A is introduced. is there.

  As shown in FIGS. 2 to 5, the heating element 34 is embedded in the first insulator 33 </ b> A forming the gas chamber 35, and generates a heating section 341 that generates heat when energized, and a heating element lead connected to the heating section 341. (Lead part) 342. The heat generating portion 341 is disposed at a position where at least a part thereof overlaps the detection electrode 311 and the reference electrode 312 in the stacking direction D of the solid electrolyte body 31 and the insulators 33A and 33B.

  The heat transfer member 38 is formed of a dense material of a metal oxide that does not allow the detection target gas G to pass therethrough. The heat transfer member 38 is sandwiched in a part of the gas chamber 35 between the detection electrode 311 and the first insulator 33A in which the heating element 34 is embedded. The heat transfer member 38 is for promoting heat transfer from the heat generating portion 341 to the solid electrolyte member 31, the detection electrode 311 and the reference electrode 312.

Hereinafter, the gas sensor 1 of the present embodiment will be described in detail.
(Internal combustion engine)
The gas sensor 1 is disposed in an exhaust pipe or the like of an internal combustion engine (engine) of a vehicle, and is used to detect an oxygen concentration or the like in the detection target gas G using exhaust gas flowing through the exhaust pipe as a detection target gas G. The gas sensor 1 can be used as an air-fuel ratio sensor for obtaining an air-fuel ratio in an internal combustion engine based on an oxygen concentration in an exhaust gas, an unburned gas concentration, and the like. In addition, the gas sensor 1 can be used for various uses other than the air-fuel ratio sensor for obtaining the oxygen concentration.

  A catalyst for purifying harmful substances in the exhaust gas is disposed in the exhaust pipe, and the gas sensor 1 can be disposed either upstream or downstream of the catalyst in the flow direction of the exhaust gas in the exhaust pipe. . In addition, the gas sensor 1 can be arranged in a pipe on the suction side of a supercharger that increases the density of the air sucked by the internal combustion engine using the exhaust gas. Further, the pipe in which the gas sensor 1 is disposed may be a pipe in an exhaust gas recirculation mechanism that recirculates a part of exhaust gas exhausted from the internal combustion engine to an exhaust pipe to an intake pipe of the internal combustion engine.

  The air-fuel ratio sensor quantitatively continuously monitors the air-fuel ratio from a fuel-rich state where the ratio of fuel to air is higher than the stoichiometric air-fuel ratio to a fuel-lean state where the ratio of fuel to air is lower than the stoichiometric air-fuel ratio. Can be detected. In the air-fuel ratio sensor, when the diffusion speed of the gas G to be detected guided to the gas chamber 35 by the diffusion resistance section (diffusion rate-controlling section) 32 is reduced, oxygen ions between the detection electrode 311 and the reference electrode 312 are generated. A predetermined voltage for exhibiting a limit current characteristic in which a current according to the movement amount is output is applied.

  As shown in FIGS. 3 and 4, when the air-fuel ratio sensor detects the air-fuel ratio on the fuel lean side, oxygen contained in the gas G to be detected becomes ions and the solid electrolyte 31 The current generated when moving to the reference electrode 312 via is detected. When the air-fuel ratio sensor detects the air-fuel ratio on the fuel-rich side, the reference electrode 312 is used to react unburned gas (hydrocarbon, carbon monoxide, hydrogen, etc.) contained in the detection target gas G. Then, the ionized oxygen moves to the detection electrode 311 via the solid electrolyte body 31, and the current generated when the unburned gas reacts with the oxygen is detected.

(Sensor element 2)
As shown in FIGS. 3 and 4, the sensor element 2 is of a stacked type in which insulators 33 </ b> A and 33 </ b> B and a heating element 34 are stacked on a solid electrolyte body 31. The solid electrolyte body 31 is made of a zirconia-based oxide, and contains zirconia as a main component (containing 50% by mass or more), and is a stabilized zirconia or a partial zirconia obtained by partially replacing zirconia with a rare earth metal element or an alkaline earth metal element. Consists of stabilized zirconia. Part of the zirconia constituting the solid electrolyte body 31 can be replaced by yttria, scandia or calcia.

  Further, the detection electrode 311 and the reference electrode 312 are provided at a position on the distal end side L1 of the sensor element 2 in the longitudinal direction L. The detection electrode 311 is provided on the first main surface 301 of the solid electrolyte body 31 that is exposed to the detection target gas G, and the reference electrode 312 is provided on the second main surface of the solid electrolyte body 31 that is exposed to the reference gas A. 302.

  The detection electrode 311 and the reference electrode 312 contain platinum as a noble metal exhibiting catalytic activity against oxygen, and zirconia-based oxide as a co-material with the solid electrolyte member 31. When the paste is printed (applied) on the solid electrolyte body 31 by sintering the solid electrode body 31 and the paste material, the detection electrode 311 and the reference electrode 312 formed by the electrode material are combined with the solid electrolyte body 31. It is for maintaining strength.

  A gas chamber 35 surrounded by the first insulator 33A and the solid electrolyte body 31 is formed adjacent to the first main surface 301 of the solid electrolyte body 31. The gas chamber 35 is formed at a position in the first insulator 33A where the detection electrode 311 is accommodated. On the second main surface 302 of the solid electrolyte body 31, a reference gas duct 36 surrounded by the second insulator 33B and the solid electrolyte body 31 is formed adjacently. The reference gas duct 36 is formed from the position where the reference electrode 312 is accommodated to the rear end position of the sensor element 2 in the second insulator 33B. At the rear end position of the sensor element 2, a rear end opening 360 of the reference gas duct 36 is formed. Further, the first insulator 33 </ b> A is provided with a diffusion resistance part 32 for introducing the detection target gas G into the gas chamber 35 at a predetermined diffusion rate, in a state communicating with the gas chamber 35.

  As shown in FIGS. 1 and 3, the sensor element 2 is formed in a long shape, and the detection electrode 311, the reference electrode 312, the gas chamber 35, the diffusion resistance part 32, and the heating part 341 of the heating element 34 are long. It is arranged at a site on the tip side L1 in the scale direction L. A detection unit 21 formed by a detection electrode 311 and a reference electrode 312 and a portion of the solid electrolyte body 31 interposed between these electrodes 311 and 312 is provided at a position on the distal end side L1 of the sensor element 2 in the longitudinal direction L. Is formed.

  The long direction L of the sensor element 2 refers to a direction in which the sensor element 2 is formed in a long shape. Also, a direction orthogonal to the longitudinal direction L and in which the solid electrolyte member 31 and the insulators 33A and 33B are stacked, in other words, a direction in which the solid electrolyte member 31, the insulators 33A and 33B and the heating element 34 are stacked. Is referred to as a stacking direction D. The direction orthogonal to the long direction L and the laminating direction D is referred to as the width direction W. Further, in the longitudinal direction L of the sensor element 2, the side on which the detecting portion 21 is formed is referred to as a front end side L1, and the side opposite to the front end side L1 is referred to as a rear end side L2.

  As shown in FIG. 2, electrode leads 313 and 314 for electrically connecting these electrodes 311 and 312 to the outside of the gas sensor 1 are connected to the detection electrode 311 and the reference electrode 312. 313 and 314 are drawn out to the site on the rear end side L2 of the long direction L. 2 and 3, the length of the sensor element 2 in the longitudinal direction L is shortened for easy understanding.

As shown in FIGS. 2 and 5, the heating element 34 includes a heating section 341 that generates heat when energized, and a pair of heating element lead sections 342 connected to the rear end side L1 of the heating section 341 in the longitudinal direction L. Having.
The heat generating portion 341 is formed by a linear conductor portion meandering by a straight line portion and a curved portion. The linear portion of the heat generating portion 341 of the present embodiment is formed in parallel with the long direction L. The heating element lead 342 is formed by a linear conductor. The resistance value of the heating unit 341 per unit length is larger than the resistance value of the heating element lead unit 342 per unit length. The heating element lead portion 342 is drawn out to a position on the rear end side L2 in the longitudinal direction L. The heating element 34 contains a metal material having conductivity.

  The heat generating portion 341 of this embodiment is formed in a shape meandering in the long direction L at a position on the distal end side L1 of the heat generating body 34 in the long direction L. Note that the heat generating portion 341 may be formed to meander in the width direction W. The heat generating portion 341 is disposed at a position facing the detection electrode 311 and the reference electrode 312 in the stacking direction D orthogonal to the long direction L. When the heating section 341 generates heat by energization from the heating element lead section 342, a portion of the detection electrode 311, the reference electrode 312, and the solid electrolyte body 31 sandwiched between the electrodes 311 and 312 has a target temperature. Heated.

  The cross-sectional area of the heating part 341 is smaller than the cross-sectional area of the heating element lead 342, and the resistance value of the heating element 341 per unit length is higher than the resistance value of the heating element lead 342 per unit length. The cross-sectional area refers to a cross-sectional area of a surface orthogonal to a direction in which the heat generating portion 341 and the heat generating element lead portion 342 extend. Then, when a voltage is applied to the pair of heating element lead portions 342, the heating portion 341 generates heat by Joule heat, and the periphery of the detection portion 21 is heated by this heat generation.

  The first insulator 33A forms the gas chamber 35 and embeds the heating element 34, and the second insulator 33B forms the reference gas duct 36. The first insulator 33A and the second insulator 33B are formed of a metal oxide such as alumina (aluminum oxide). Each of the insulators 33A and 33B is formed as a dense body through which the detection target gas G or the reference gas A cannot pass, and each of the insulators 33A and 33B has almost all pores through which the gas can pass. It has not been.

  As shown in FIGS. 2 and 3, the first insulator 33A is laminated on the insulating spacer 331 having a through hole 332 penetrated in the laminating direction D to form the gas chamber 35, and on the insulating spacer 331. It is formed by buried plates 334A and 334B for burying the heating element 34. The heating element 34 is buried between the burying plates 334A and 334B.

  The gas chamber 35 is formed as a space closed by the first insulator 33A, the diffusion resistance part 32, and the solid electrolyte body 31. The detection target gas G, which is the exhaust gas flowing in the exhaust pipe, passes through the diffusion resistance part 32 and is introduced into the gas chamber 35.

  The diffusion resistance portion 32 of the present embodiment is formed adjacent to the distal end side L1 in the longitudinal direction L of the gas chamber 35. The diffusion resistance portion 32 is disposed in the inlet 333 opened in the insulating spacer 331 of the first insulator 33A adjacent to the distal end side L1 of the gas chamber 35 in the longitudinal direction L. The diffusion resistance section 32 is formed of a porous metal oxide such as alumina. The diffusion speed (flow rate) of the detection target gas G introduced into the gas chamber 35 is determined by limiting the speed at which the detection target gas G permeates the pores in the diffusion resistance portion 32.

  The diffusion resistance portion 32 may be formed adjacent to both sides of the gas chamber 35 in the width direction W. In this case, the diffusion resistance portion 32 is arranged in the inlet 333 opened adjacent to both sides of the gas chamber 35 in the width direction W in the insulating spacer 331 of the first insulator 33A. The diffusion resistance portion 32 can be formed using a pinhole, which is a small through-hole that is communicated with the gas chamber 35, instead of using a porous body.

  As shown in FIGS. 2 and 3, the second insulator 33 </ b> B is formed by an insulating spacer 335 having a cutout 336 constituting the reference gas duct 36 and an insulating plate 337 laminated on the insulating spacer 335. ing. In the insulating spacer 331 of the first insulator 33A and the insulating spacer 335 of the second insulator 33B, the through-hole 332 or the notch 336 can be formed by various methods such as molding, cutting, and applying paste. .

  The reference gas duct 36 is formed as a duct for the reference gas A having an open rear end L2 in the long direction L. The reference gas duct 36 is formed from the rear end position of the sensor element 2 in the longitudinal direction L to a position facing the gas chamber 35 via the solid electrolyte body 31. The reference electrode 312 is accommodated in the reference gas duct 36 at a position on the distal end side L1. Atmosphere as the reference gas A is introduced into the reference gas duct 36 from a rear end opening 360 located at the rear end of the sensor element 2.

  The cross-sectional area of the cross section of the reference gas duct 36 perpendicular to the long direction L is larger than the cross sectional area of the gas chamber 35 perpendicular to the long direction L. The thickness (width) of the reference gas duct 36 in the stacking direction D is larger than the thickness (width) of the gas chamber 35 in the stacking direction D. Since the cross-sectional area, thickness, volume, and the like of the reference gas duct 36 are larger than the cross-sectional area, thickness, volume, and the like of the gas chamber 35, oxygen in the reference gas A for reacting unburned gas in the detection electrode 311 is reduced. , From the reference gas duct 36 to the detection electrode 311.

  As shown in FIG. 1, a porous layer for capturing the poisoning substance for the detection electrode 311, condensed water generated in the exhaust pipe, and the like is provided around the entire front end portion L <b> 1 of the sensor element 2 in the longitudinal direction L. 37 are provided. The porous layer 37 is formed of a porous ceramic (metal oxide) such as alumina. The porosity of the porous layer 37 is larger than the porosity of the diffusion resistance part 32, and the flow rate of the detection target gas G that can pass through the porous layer 37 is the detection target that can pass through the diffusion resistance part 32. It is larger than the flow rate of the gas G.

(Heat transfer member 38)
As shown in FIGS. 3 and 4, the heat transfer member 38 is bridged between the detection electrode 311 and the first insulator 33A in a state of being in contact with a part of the detection electrode 311. In the cross section orthogonal to the stacking direction D of the sensor element 2, the cross sectional area of the heat transfer member 38 is smaller than the cross sectional area of the detection electrode 311. The heat transfer member 38 of this embodiment has a columnar shape between the surface of the detection electrode 311 and the inner wall surface of the first insulator 33A near the center of the plane of the detection electrode 311 (in the cross section orthogonal to the stacking direction D). Are located in The heat transfer member 38 of the present embodiment is formed in a round cross section. In addition, the heat transfer member 38 can be formed in various cross-sectional shapes.

  The heat transfer member 38 can be formed in a rectangular shape near the center of the detection electrode 311 as shown in FIG. 6, for example. Further, as shown in FIG. 7, the heat transfer member 38 is arranged not only at a position facing the detection electrode 311 but also at a position protruding from the detection electrode 311 and facing the first main surface 301 of the solid electrolyte body 31. be able to. Further, the heat transfer member 38 can be formed continuously from one end face of the detection electrode 311 to the other end face. The rectangular heat transfer member 38 may have a long shape in the long direction L or a long shape in the width direction W. Further, the heat transfer member 38 can be formed by a portion extending in the long direction L and a portion extending in the width direction W. Further, the heat transfer members 38 may be arranged at a plurality of positions between the detection electrode 311 and the first insulator 33A.

  By increasing the cross-sectional area of the heat transfer member 38 perpendicular to the stacking direction D, the heat transfer through the heat transfer member 38 can be enhanced. However, when the heat transfer member 38 is in contact with the detection electrode 311, the surface area of the detection electrode 311 decreases as the area of the heat transfer member 38 in contact with the detection electrode 311 increases. Therefore, the cross-sectional area of the heat transfer member 38 can be determined in consideration of the balance between the heat transfer from the heat generating portion 341 to the solid electrolyte body 31 and the like and the electrochemical reaction at the detection electrode 311.

  The heat transfer member 38 can be formed by applying a paste-like metal oxide to the first insulator 33A or the detection electrode 311 and then sintering the entire sensor element 2. Further, a solid spacer for forming the heat transfer member 38 is disposed between the first insulator 33A and the detection electrode 311. Thereafter, the entire heat transfer member 38 is sintered by sintering the entire sensor element 2. It can also be formed.

  At the interface between the heat transfer member 38 and the detection electrode 311, the heat conductivity of the heat transfer member 38 is improved because the heat conductivity of the noble metal forming the detection electrode 311 is higher than the heat conductivity of the metal oxide. . On the other hand, at the interface between the heat transfer member 38 and the first insulator 33A, the heat conductivity of the heat transfer member 38 decreases, but the metal oxides are firmly bonded to each other.

  The heat transfer member 38 may be made of an insulating metal oxide, and may be made of zirconia, aluminum nitride, silicon carbide, or the like, in addition to alumina. The heat transfer member 38 has a property of hardly allowing gas to pass therethrough as a dense material. In the heat transfer member 38, since the metal oxide particles are sintered to each other, almost no gap is formed between the particles, and the exhaust gas as the detection target gas G cannot pass therethrough. I have. Further, since almost no gap is formed in the heat transfer member 38, the heat transfer property of the heat transfer member 38 can be enhanced.

(Other Configuration of Gas Sensor 1)
As shown in FIG. 1, in addition to the sensor element 2 and the like, the gas sensor 1 includes a first insulator 42 holding the sensor element 2, a housing 41 holding the first insulator 42, and a second insulator 42 connected to the first insulator 42. The insulator 43 includes a contact terminal 44 held by the second insulator 43 and in contact with the sensor element 2. Further, the gas sensor 1 has a front end cover 45 mounted on the front end side L1 of the housing 41, and a rear end side mounted on the rear end L2 of the housing 41 to cover the second insulator 43, the contact terminals 44, and the like. A cover 46 and a bush 47 for holding a lead wire 48 connected to the contact terminal 44 to the rear end cover 46 are provided.

  The tip side cover 45 is arranged in an exhaust pipe of the internal combustion engine. A gas passage hole 451 for allowing exhaust gas as the detection target gas G to pass therethrough is formed in the distal end side cover 45. The distal end cover 45 may have a double structure or a single structure. Exhaust gas as the gas to be detected G flowing into the front cover 45 from the gas passage hole 451 of the front cover 45 passes through the porous layer 37 and the diffusion resistance portion 32 of the sensor element 2 and is guided to the detection electrode 311. I will be.

  As shown in FIG. 1, the rear end side cover 46 is arranged outside the exhaust pipe of the internal combustion engine. An air introduction hole 461 for introducing the atmosphere as the reference gas A into the rear end cover 46 is formed in the rear end cover 46. The air introduction hole 461 is provided with a filter 462 which does not allow liquid to pass therethrough but allows gas to pass therethrough. The reference gas A introduced from the air introduction hole 461 into the rear end side cover 46 is guided to the reference electrode 312 through the gap in the rear end side cover 46 and the reference gas duct 36.

  As shown in FIGS. 1 and 2, the contact terminal 44 is connected to each of the electrode lead 313 of the detection electrode 311, the electrode lead 314 of the reference electrode 312, and the heating element lead 342 of the heating element 34. The plurality of second insulators 43 are arranged. The lead wires 48 are connected to the respective contact terminals 44.

  As shown in FIGS. 1 and 3, the lead wire 48 of the gas sensor 1 is electrically connected to a sensor control device 6 that controls gas detection in the gas sensor 1. The sensor control device 6 performs electric control in the gas sensor 1 in cooperation with an engine control device that controls combustion operation in the engine. The sensor control device 6 includes a measurement circuit 61 for measuring a current flowing between the detection electrode 311 and the reference electrode 312, an application circuit 62 for applying a voltage between the detection electrode 311 and the reference electrode 312, and a heating element 34. An energizing circuit and the like for energizing are formed. Note that the sensor control device 6 may be constructed in the engine control device.

(Production method)
In manufacturing the sensor element 2, the solid electrolyte body 31, the insulators 33A and 33B, the diffusion resistance part 32, the heating element 34, and the like are stacked to form a laminate, and the laminate is heated and sintered. The detection electrode 311 and the reference electrode 312 are formed by printing (applying) a paste material containing platinum, a solid electrolyte, a solvent, and the like on the solid electrolyte body 31 and sintering the stacked body of the sensor element 2. Are formed by sintering.

(Effect)
In the gas sensor 1 of the present embodiment, the heating element 34 is buried in the first insulator 33A forming the gas chamber 35, and a part of the gas chamber 35 is connected to the detection electrode 311 and the first insulator 33A. A heat transfer member 38 is sandwiched between them. The heat transfer member 38 is formed of a dense material of a metal oxide that does not allow the exhaust gas as the detection target gas G to pass therethrough, and extends from the heat generating portion 341 of the heat generating member 34 to the solid electrolyte member 31 and the electrodes 311 and 312. Promotes heat transfer.

  When the gas sensor 1 is used, when the solid electrolyte body 31 and each of the electrodes 311 and 312 are heated by the heat generated by the heat generation unit 341, the heat in the heat generation unit 341 is transferred to the solid electrolyte body 31 via the first insulator 33 </ b> A. In addition, the heat is transmitted to the electrodes 311 and 312 and also to the solid electrolyte body 31 and the electrodes 311 and 312 via the heat transfer member 38. At this time, heat is transferred from the heating section 341 to the solid electrolyte body 31 and the electrodes 311 and 312 via the first insulator 33A so as to bypass the gas chamber 35, while the heat transfer section 341 transfers heat from the heating section 341 to the heat transfer member. Heat is directly transferred to the solid electrolyte member 31 and the electrodes 311 and 312 via the connection member 38.

  Thereby, the heat conductivity from the heat generating portion 341 to the solid electrolyte member 31 and the electrodes 311 and 312, in other words, the heat conductivity of the sensor element 2 can be increased. Further, at the time of starting the gas sensor 1 or the like, the time for heating the sensor element 2 to a temperature at which the conductivity of oxygen ions is activated by the heat generated by the heat generating portion 341 can be reduced.

  In addition, when the gas sensor 1 is used, heat generated by the heat generating portion 341 can be effectively transmitted to the solid electrolyte body 31 and the electrodes 311 and 312. Therefore, power consumption of the heating element 34 when the sensor element 2 is heated by the heating element 34 can be reduced.

  Further, in the present embodiment, since the heating element 34 is embedded in the first insulator 33A forming the gas chamber 35, the distance between the heating element 34 and the solid electrolyte body 31 can be reduced. The time for heating the solid electrolyte body 31 and the electrodes 311 and 312 by the heating section 341 of the heating element 34 can be further reduced.

  Therefore, according to the gas sensor 1 of the present embodiment, the heat conductivity of the sensor element 2 can be enhanced, and the sensor element 2 can be activated early.

<Embodiment 2>
In the present embodiment, the sensor element 2 in which the heating element 34 is embedded inside the second insulator 33B will be described.
As shown in FIGS. 8 and 9, a reference gas duct 36 into which the reference gas A is introduced is formed in the second insulator 33B. The heating element 34 is disposed on the second insulator 33B so as to face the reference electrode 312. The heat transfer member 38 of this embodiment is sandwiched between a reference electrode 312 and a second insulator 33B in which the heating element 34 is embedded, in a part of the reference gas duct 36.

  The second insulator 33B can be formed by forming the reference gas duct 36 and laminating the insulating spacer 335 and the insulating plates 337A and 337B in which the heating element 34 is embedded. The first insulator 33A can be formed by stacking the insulating spacer 331 and the insulating plate 334 so as to form the gas chamber 35.

  Also in the sensor element 2 of the present embodiment, the heat generated from the heat generating portion 341 of the heat generating element 34 is effectively transmitted to the solid electrolyte member 31 and the respective electrodes 311 and 312 via the second insulator 33B and the heat transfer member 38. be able to. Therefore, according to the gas sensor 1 of the present embodiment, as in the case of the first embodiment, the heat conductivity of the sensor element 2 can be enhanced, and the sensor element 2 can be activated early.

  Other configurations, operational effects, and the like of the gas sensor 1 of the present embodiment are the same as those of the first embodiment. Also in this embodiment, the components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

<Embodiment 3>
In the present embodiment, various arrangement relationships between the heat generating portion 341 of the heat generating element 34 and the heat transfer member 38 will be described.
In this embodiment, as shown in FIG. 10, a part of the heat generating part 341 and a part of the heat transfer member 38 are arranged at positions overlapping each other in the stacking direction D. In this embodiment, the case where the heating element 34 is buried in the first insulator 33A will be described. In the heat generating section 341, a heat generating center at which the temperature is the highest is formed in a plane where the heat generating section 341 is provided and which is orthogonal to the lamination direction D (in a plane parallel to the long direction L and the width direction W).

  The heat generation center is formed near the center in the long direction L and the width direction W of the arrangement position of the heat generation portion 341 on the first insulator 33A. The heat generation center forms a heat spot as an area where heat is intensively generated after a lapse of one second from the start of energization of the heat generator 34. The position where the heat spot is formed changes according to the formation state of the heat generating portion 341, the degree of overlap of the heat transfer member 38 and the heat generating portion 341 in the stacking direction D, and the like. In the present embodiment, the heat spot is formed near the center position in the plane of the detection electrode 311.

  As shown in FIG. 10, the heat generating portion 341 of the present embodiment is formed to meander in the longitudinal direction L, and includes a plurality of parallel portions 343A and 343B parallel to the longitudinal direction L and the parallel portions 343A and 343B. And a connecting portion 344 that connects the two in a curve. The parallel portions 343A and 343B include a pair of inner parallel portions 343A formed at a position inside the width direction W and a pair of outer parallel portions 343B formed at a position outside the width direction W with respect to the inside parallel portion 343A. And

  The interval in the width direction W between the pair of inner parallel portions 343A is smaller than the interval between the adjacent inner parallel portion 343A and the outer parallel portion 343B. A part of the heat transfer member 38 is disposed at a position overlapping a part of the pair of inner parallel portions 343A in the stacking direction D. Since the interval between the pair of inner parallel portions 343A is smaller than the interval between the inner parallel portion 343A and the outer parallel portion 343B adjacent to each other, a part of the heat transfer member 38 is stacked on the pair of inner parallel portions 343A in the stacking direction D. Can easily face each other.

  The heat transfer member 38 is formed in parallel with the long direction L in a plane parallel to the long direction L and the width direction W, and a part of the heat transfer member 38 is formed as a part of the pair of inner parallel portions 343A. In the stacking direction D. In this case, as shown in FIG. 11, the heat transfer member 38 can be provided at a position facing the one inner parallel portion 343A in the stacking direction D.

  As shown in FIG. 12, the heat transfer member 38 is formed to be inclined with respect to the long direction L in a plane parallel to the long direction L and the width direction W, and a part of the heat transfer member 38. Can be opposed to a part of the pair of inner parallel portions 343A in the stacking direction D. In this case, the heat transfer member 38 can be formed so as to partially face the pair of inner parallel portions 343A in the stacking direction D.

  Further, as shown in FIG. 13, the heat transfer members 38 may be formed in a pair so as to face each of the pair of inner parallel portions 343A in the stacking direction D. In this case, the heat transfer member 38 can be formed parallel to the inner parallel portion 343A. Further, in this case, as shown in FIG. 14, the heat transfer member 38 can be formed in a state facing the laminating direction D with respect to a plurality of portions in the longitudinal direction L of each inner parallel portion 343A.

  In addition, as shown in FIG. 15, the heat generating portion 341 of the heat generating element 34 can be formed so as to meander in the width direction W. The heat generating portion 341 can be formed by a pair of meandering portions 345 connected to the pair of heat generating element lead portions 342 in the longitudinal direction L. The meandering portion 345 is formed by alternately forming an inner curved portion 346A formed in a curved shape at an inner position in the width direction W and an outer curved portion 346B formed in a curved shape at an outer position in the width direction W. I have.

  The heat transfer member 38 can be disposed at a position overlapping the plurality of inner curved portions 346A of the pair of meandering portions 345 in the stacking direction D. In addition, as shown in FIG. 16, the heat transfer member 38 can be disposed at a position that overlaps the inner curved portion 346A of the one meandering portion 345 in the stacking direction D. In these cases, the heat transfer member 38 can be formed parallel to the longitudinal direction L of the sensor element 2.

  As shown in FIG. 17, the heat transfer member 38 is formed to be inclined with respect to the long direction L in a plane parallel to the long direction L and the width direction W, and a part of the heat transfer member 38. Can be arranged at a position overlapping a part of the pair of meandering portions 345 in the stacking direction D. Further, as shown in FIG. 18, the heat transfer members 38 may be formed in a pair so as to face each of the pair of meandering portions 345 in the stacking direction D. In this case, the heat transfer member 38 can be formed at a position that overlaps the inner curved portion 346A of the pair of meandering portions 345 in the stacking direction D, and is stacked on the inner curved portion 346A and the outer curved portion 346B of the pair of meandering portions 345. It can also be formed at a position overlapping in the direction D.

  The heating portion 341 of the heating element 34 does not necessarily have to meander if the specific resistance is higher than that of the heating element lead portion 342. As shown in FIG. 19, the heat generating portion 341 is formed as a pair of parallel portions connected to the pair of heating element lead portions 342 and parallel to the longitudinal direction L of the sensor element 2 and a connecting portion connecting the pair of parallel portions. You can also. In this case, the heat transfer member 38 can be formed at a position overlapping the pair of parallel portions in the stacking direction D. In addition, as shown in FIG. 20, the heat transfer member 38 can be formed at a position overlapping one of the parallel portions in the stacking direction D.

  In this case, as shown in FIG. 21, the heat transfer member 38 may be formed to be inclined in the long direction L so as to overlap the pair of parallel portions in the stacking direction D. Further, as shown in FIG. 22, the heat transfer members 38 may be formed in a pair so as to face each of the pair of parallel portions in the stacking direction D.

  Also in the present embodiment, the heating element 34 can be embedded in the second insulator 33B instead of being embedded in the first insulator 33A. Also in this case, the heat generating portion 341 and the heat transfer member 38 can be arranged in various positional relationships overlapping in the stacking direction D.

  Other configurations, operational effects, and the like of the gas sensor 1 of the present embodiment are the same as those of the first embodiment. Also in this embodiment, the components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

<Embodiment 4>
In the present embodiment, a case where the sensor element 2 has a plurality of solid electrolyte bodies 31A and 31B will be described.
As shown in FIGS. 23 and 24, the sensor element 2 of the present embodiment has two solid electrolyte bodies 31A and 31B, and is provided in a part of a gas chamber 35 located between the solid electrolyte bodies 31A and 31B. It has a heat transfer member 38. The two solid electrolyte members 31A and 31B include a first solid electrolyte member 31A having a first pump electrode 311A and a second pump electrode 311B, and a second solid electrolyte member 31B having a detection electrode 312A and a reference electrode 312B. .

  The first solid electrolyte body 31A has oxygen ion conductivity. The first solid electrolyte body 31A is located farther from the third insulator 33E in which the heating element 34 is embedded, of the two solid electrolyte bodies 31A and 31B. The first pump electrode 311A and the second pump electrode 311B are provided at positions facing each other at a position on the distal end side L1 in the longitudinal direction L of the first solid electrolyte body 31A. The second solid electrolyte member 31B is disposed to face the first solid electrolyte member 31A, and has oxygen ion conductivity. The detection electrode 312A and the reference electrode 312B are provided at positions facing each other at a position on the distal end side L1 in the longitudinal direction L of the second solid electrolyte body 31B.

  The sensor element 2 of the present embodiment includes a first insulator 33C, a second insulator 33D for forming the gas chamber 35, and a third insulator 33E for burying the heating element 34. The first insulator 33C is stacked on the main surface of the first solid electrolyte body 31A on which the first pump electrode 311A is provided. The first insulator 33C is provided with a porous body 39 for protecting the first pump electrode 311A and introducing the detection target gas G to the first pump electrode 311A.

  As shown in FIGS. 23 and 24, the second insulator 33D is provided with the main surface of the first solid electrolyte body 31A on which the second pump electrode 311B is provided and the detection electrode 312A of the second solid electrolyte body 31B. It is sandwiched between the main surface. On both sides of the second insulator 33D in the width direction W, diffusion resistance portions 32 that allow the detection target gas G to pass therethrough are arranged. The diffusion resistance section 32 may be arranged at a position on the distal end side L1 in the long direction L of the second insulator 33D. The main surface of the first solid electrolyte body 31A on which the second pump electrode 311B is provided and the main surface of the second solid electrolyte body 31B on which the detection electrode 312A is provided face each other.

  The third insulator 33E is stacked on the main surface of the second solid electrolyte body 31B on which the reference electrode 312B is provided. The third insulator 33E is formed by a pair of insulating plates 339 that bury the heating element 34 therebetween. The reference electrode 312 is embedded between the second solid electrolyte body 31B and the third insulator 33E and is embedded in the third insulator 33E.

  The first pump electrode 311A and the second pump electrode 311B are arranged at positions facing each other in the first solid electrolyte body 31A. The detection electrode 312A and the reference electrode 312B are arranged at positions facing each other in the second solid electrolyte body 31B. The second pump electrode 311B and the detection electrode 312A face each other in the gas chamber 35.

  The heating element 34 is embedded in the third insulator 33 </ b> E, and includes a heating section 341 that generates heat when energized, and a heating element lead section 342 that is connected to the rear end side L <b> 2 of the heating section 341 in the longitudinal direction L. . At least a part of the heat generating portion 341 is disposed at a position overlapping each of the electrodes 311A, 311B, 312A, 312B in the stacking direction D of the solid electrolyte members 31A, 31B and the insulators 33C, 33D, 33E.

  The gas chamber 35 is formed so as to be surrounded by the first solid electrolyte body 31A, the second solid electrolyte body 31B, and the second insulator 33D, and is formed at a position that houses the second pump electrode 311B and the detection electrode 312A. I have. The diffusion resistance part 32 is provided in the second insulator 33D in communication with the gas chamber 35, and is for introducing the detection target gas G into the gas chamber 35 at a predetermined diffusion rate.

  As shown in FIGS. 23 and 24, the heat transfer member 38 is sandwiched between the second pump electrode 311B and the detection electrode 312A in a part of the gas chamber 35, This is for promoting heat transfer to the body 31A, the first pump electrode 311A, and the second pump electrode 311B. The heat transfer member 38 can be arranged not only at one place in the gas chamber 35 but also at a plurality of places in the gas chamber 35. As described in the third embodiment, the heat transfer member 38 of this embodiment can also be arranged at a position overlapping the heat generating portion 341 in the stacking direction D.

  In the gas sensor 1 using the sensor element 2 of this embodiment, a voltage is applied between the first pump electrode 311A and the second pump electrode 311B, and the oxygen concentration of the gas G to be detected introduced into the gas chamber 35 is reduced. Adjusted. Further, a voltage for generating a limiting current characteristic is applied between the detection electrode 312A and the reference electrode 312B by utilizing the diffusion resistance portion 32, and the voltage is applied to the detection electrode 312A according to the oxygen concentration in the gas chamber 35. A sensor current flowing between the reference electrode 312B and the reference electrode 312B is detected. The sensor control device 6 of the gas sensor 1 can obtain the air-fuel ratio or the like of the internal combustion engine specified from the detection target gas G based on the sensor current.

  In the present embodiment, the heat of the heat generating portion 341 passes through the third insulator 33E and the second solid electrolyte body 31B, and also passes through the second insulator 33D located around the gas chamber 35, thereby causing the first solid to flow. It is transmitted to the electrolyte body 31A and the first and second pump electrodes 311B. Further, due to the presence of the heat transfer member 38, the heat of the heat generating portion 341 is transferred from the detection electrode 312A of the second solid electrolyte body 31B to the second pump electrode 311B of the first solid electrolyte body 31A via the heat transfer member 38. Is transmitted. Then, the heat of the heat generating portion 341 is not only transmitted to the first solid electrolyte body 31A via the second insulator 33D around each of the electrodes 311A, 311B, 312A, 312B, but also to each of the electrodes 311A, 311B, The heat is transmitted to the first solid electrolyte body 31A via the heat transfer members 38 and 312A and 312B.

  Thereby, in the present embodiment, the heat transfer from the heat generating portion 341 to the first solid electrolyte body 31A, the first pump electrode 311A, and the second pump electrode 311B can be improved. According to the gas sensor 1 of the present embodiment, as in the case of the first embodiment, the heat conductivity of the sensor element 2 can be increased, and the sensor element 2 can be activated early.

  Other configurations, operational effects, and the like of the gas sensor 1 of the present embodiment are the same as those of the first embodiment. Also in this embodiment, the components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

<Embodiment 5>
This embodiment shows a case where the heat transfer member 38 is sandwiched between the first insulator 33A, the detection electrode 311 and the solid electrolyte body 31 in the sensor element 2 shown in the first embodiment.
As shown in FIGS. 25 and 26, the heat transfer member 38 is provided at a position straddling the detection electrode 311 and the solid electrolyte member 31. The detection electrode 311 is formed with a through hole 315 penetrating the detection electrode 311 in the stacking direction D. The through-hole 315 of this embodiment is formed at the center of the detection electrode 311, and is formed in a rectangular shape that is long in the longitudinal direction L of the detection electrode 311. The heat transfer member 38 is provided in contact with a part of the detection electrode 311 and a part of the solid electrolyte body 31.

  The heat transfer member 38 is in contact with the solid electrolyte body 31 via the through hole 315 and is in contact with the edge of the through hole 315 in the detection electrode 311. In other words, the heat transfer member 38 is formed so as to overlap from the surface of the solid electrolyte member 31 to the surface of the detection electrode 311. The heat transfer member 38 of this embodiment is formed in a shape following the rectangular shape of the through hole 315.

  FIG. 27 shows a cross section orthogonal to the longitudinal direction L of the sensor element 2, in the range of the length in the width direction W where the heat transfer member 38 contacts the solid electrolyte body 31 and the detection electrode 311. And an overlap ratio α between the detection electrode 311 and the detection electrode 311. When the width of the heat transfer member 38 in the width direction W is d and the ranges on both sides where the heat transfer member 38 and the detection electrode 311 overlap are d1 and d2, the overlap ratio α is α = (d1 + d2) / d. Represented by

  The figure shows how the electric resistance ratio of the detection electrode 311 changes when the overlap ratio α changes between 0 and 1. The electric resistance ratio of the detection electrode 311 is set to 1 based on the case where the heat transfer member 38 is not provided in the sensor element 2. The case where the overlap ratio α is 1 indicates that the entire heat transfer member 38 is in contact with the detection electrode 311. The overlap ratio α is reduced by increasing the size of the through hole 315 formed in the detection electrode 311 in accordance with the location of the heat transfer member 38. A case where the overlap ratio α is 0 indicates a case where the entirety of the heat transfer member 38 is in contact with the solid electrolyte member 31 in a state of being disposed in the through hole 315. When the overlap ratio α decreases, the area of the detection electrode 311 decreases, and the electrical resistance ratio of the detection electrode 311 increases.

  The electric resistance of the detection electrode 311 refers to the electric resistance of the detection electrode 311 when a current due to oxygen ions flows between the detection electrode 311 and the reference electrode 312 via the solid electrolyte body 31. The graph in the figure shows the electric resistance when the detection electrode 311 is at 750 ° C. It can be seen that when the overlap ratio is smaller than 0.4, the rate of increase in the electric resistance ratio of the detection electrode 311 increases. Therefore, it is preferable that the overlap ratio is 0.4 or more.

  Since the heat transfer member 38 of the present embodiment is in contact with the detection electrode 311 and the solid electrolyte member 31, the decrease in the effective surface area of the detection electrode 311 can be suppressed, and the bonding strength of the heat transfer member 38 can be increased. . More specifically, since the heat transfer member 38 is also in contact with the solid electrolyte body 31, the area of the heat transfer member 38 covering the detection electrode 311 is reduced, and the effective surface area of the detection electrode 311 is kept large. . Thus, an increase in electric resistance when gas detection is performed by the gas sensor 1 can be suppressed.

  In addition, since the heat transfer member 38 is joined not only to the detection electrode 311 but also to the solid electrolyte member 31, the heat transfer member 38 and the solid electrolyte member 31 are firmly bonded by bonding between metal oxides. Thereby, the joining strength of the heat transfer member 38 in the sensor element 2 can be increased. Also in this embodiment, the heat transfer member 38 can enhance the heat transfer of the sensor element 2.

  Note that, instead of forming the through hole 315, a cutout for partially cutting out the detection electrode 311 may be formed in the detection electrode 311. The through hole 315 and the notch are formed by a portion where the detection electrode 311 is not formed within the substantially rectangular outer shape of the detection electrode 311 so that the surface of the solid electrolyte body 31 is exposed.

  Other configurations, operational effects, and the like of the gas sensor 1 of the present embodiment are the same as those of the first embodiment. Also in this embodiment, the components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

<Embodiment 6>
In the present embodiment, as shown in FIG. 28, in the sensor element 2 according to the second embodiment, the heat transfer member 38 is sandwiched between the second insulator 33B, the reference electrode 312, and the solid electrolyte body 31. Show.
The heating element 34 of the present embodiment is embedded inside the second insulator 33B in which the reference gas duct 36 is formed. The heat transfer member 38 is provided at a position straddling the reference electrode 312 and the solid electrolyte member 31. In the reference electrode 312, a through hole 315 penetrating the reference electrode 312 in the stacking direction D is formed. The through hole 315 of this embodiment is formed at the center of the reference electrode 312. Heat transfer member 38 is provided in contact with a part of reference electrode 312 and a part of solid electrolyte body 31.

  The heat transfer member 38 is in contact with the solid electrolyte body 31 through the through hole 315 and is in contact with the edge of the through hole 315 in the reference electrode 312. In other words, the heat transfer member 38 is formed so as to overlap from the surface of the solid electrolyte member 31 to the surface of the reference electrode 312.

  Also in the present embodiment, the same function and effect as the sensor element 2 of the fifth embodiment can be obtained by the heat transfer member 38 that comes into contact with the reference electrode 312 and the solid electrolyte body 31. Other configurations, operational effects, and the like of the gas sensor 1 of the present embodiment are the same as those of the first embodiment. Also in this embodiment, the components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

<Embodiment 7>
In the present embodiment, for the sensor element 2 shown in the first embodiment, the position where the heat transfer member 38 is provided on the surface of the detection electrode 311 was examined.
As a result of the inventor's research, when the heat transfer member 38 is provided on the surface of the detection electrode 311, the heat transfer member 38 is a portion of the detection electrode 311 where the detection target gas G that has passed through the diffusion resistance part 32 first contacts. It was found that it was better not to provide them.

  As shown in FIG. 29, in the sensor element 2, the diffusion resistance portion 32 is provided at a position on the distal end side L <b> 1 in the long direction L of the first insulator 33 </ b> A. The detection target gas G is introduced from the distal end side L1 of the sensor element 2 in the long direction L via the sensor element 32. The heat transfer member 38 is provided in contact with a part of the surface of the detection electrode 311. The cross-sectional area of the heat transfer member 38 in a cross section orthogonal to the stacking direction D is smaller than the cross-sectional area of the detection electrode 311 in a cross section orthogonal to the stack direction D.

  The heat transfer member 38 is provided in contact with a part of the detection electrode 311 except for a part of the detection electrode 311 on the distal end side L1 in the longitudinal direction L close to the diffusion resistance part 32. The portion on the distal end side L1 in the longitudinal direction L of the detection electrode 311 is exposed to the detection target gas G because the heat transfer member 38 is not in contact.

  FIG. 30 shows the position of the detection electrode 311 from the distal end 316 in the longitudinal direction L to the proximal side L2, and the position of the detection electrode 311 when a current flows when gas detection is performed between the detection electrode 311 and the reference electrode 312. The relationship with the accumulated current is shown. In the detection electrode 311, the electrochemical reaction is started in order from the front end side L <b> 1 in the long direction L in which the detection target gas G first contacts. Then, the electrochemical reaction becomes weaker toward the base end side L2 in the longitudinal direction L of the detection electrode 311.

  If the surface of the detection electrode 311 at the front end portion in the longitudinal direction L is closed by the heat transfer member 38, oxygen to be decomposed at the front end portion and detected as current is diffused. Therefore, it is preferable that the heat transfer member 38 does not contact the surface of the detection electrode 311 at the front end portion in the long direction L.

  The cumulative current represents a current that is accumulated and increases from the distal end 316 in the longitudinal direction L of the detection electrode 311 toward the base end L2, assuming that the current flowing through the entire detection electrode 311 is 100%. The accumulated current is 0% at the distal end 316 of the detection electrode 311 in the longitudinal direction L, but becomes approximately 100% at a position moved 4 mm from the distal end 316 of the detection electrode 311 to the proximal side L2.

  In other words, the current flowing through the detection electrode 311 becomes the maximum at a position moved by 4 mm or more from the distal end 316 of the detection electrode 311 to the proximal side L2. When a cumulative current of at least about 50% is obtained, an electrochemical reaction at the detection electrode 311 is obtained, so that the heat transfer member 38 is separated from the end 316 of the detection electrode 311 in the longitudinal direction L by 0.2 mm or more. It can be provided from the position toward the base end side L2. Further, in order to obtain a cumulative current of at least about 70%, the heat transfer member 38 is provided from a position separated from the distal end 316 in the longitudinal direction L of the detection electrode 311 by 0.5 mm or more toward the base end side L2. Is preferred.

  Further, in FIG. 31, in various cases in which the position of the heat transfer member 38 in the longitudinal direction L with respect to the detection electrode 311 is changed, the air-fuel ratio (A / F ) Shows a simulation result of how long a response time for detecting a change from A / F = 15 to A / F = 14 is obtained. The length of the heat transfer member 38 in the longitudinal direction L was 4 mm, the width of the heat transfer member 38 in the width direction W was 1 mm, and the width of the detection electrode 311 in the width direction W was 2 mm. The distance from the tip 316 in the long direction L of the detection electrode 311 to the tip 381 in the long direction L of the heat transfer member 38 was Lx [mm], and this distance Lx was changed in the range of 0 to 4 mm. .

  In the figure, the response time is set to 1 based on the case where the distance Lx is 4 mm, and it is determined how much the response time relatively changes as the distance Lx changes. It was found that when the distance Lx was 0 mm, the response time was about 1.8, and when the distance Lx was 0.2 mm, the response time was about 1.3. Accordingly, the distal end 381 in the long direction L of the heat transfer member 38 in contact with the detection electrode 311 is separated from the distal end 316 in the long direction L of the detection electrode 311 by 0.2 mm or more in the longitudinal direction L. It is preferable to be away to the end side L2. Further, the distal end 381 in the long direction L of the heat transfer member 38 at the position in contact with the detection electrode 311 is closer to the base end in the long direction L by 0.5 mm or more from the front end 316 in the long direction L of the detection electrode 311. More preferably, it is away from L2.

  Further, in addition to forming the heat transfer member 38 into a linear columnar shape having a constant cross-sectional area in a plane direction orthogonal to the laminating direction D of the solid electrolyte body 31, as shown in FIG. Can be formed in a trapezoidal column shape in which the cross-sectional area in the planar direction becomes smaller as approaching the detection electrode 311. In particular, the side surface of the distal end side L1 of the heat transfer member 38 can be inclined so as to be located on the proximal end side L2 as approaching the detection electrode 311. Also in this case, the tip 381 in the long direction L of the heat transfer member 38 at the position in contact with the detection electrode 311 is at least 0.2 mm from the tip 316 in the long direction L of the detection electrode 311. It is preferable to be away from the base side L2.

  Other configurations, operational effects, and the like of the gas sensor 1 of the present embodiment are the same as those of the first embodiment. Also in this embodiment, the components denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

<Confirmation test>
In this confirmation test, the sensor element 2 of the first embodiment, in which the heating element 34 is embedded in the first insulator 33C and the heat transfer member 38 is disposed, is heated to a target operating temperature (active temperature). The time required for the measurement was measured. For comparison, the time required to heat a conventional sensor element, in which the heating element 34 is embedded in the second insulator 33B and the heat transfer member 38 is not disposed, to the operating temperature was measured. As a result of the measurement, in the gas sensor 1 using the sensor element 2 of the first embodiment, when the activation time from the start of heating to reaching the operating temperature is 100% of the activation time of the conventional gas sensor. In addition, it was confirmed that the activation time of the conventional gas sensor was reduced to about 30%. In the gas sensor 1 using the sensor element 2 of the first embodiment, the energizing time to the heating element 34 from the normal temperature (25 ° C.) to the operating temperature (for example, 650 ° C.) is set to 1 second or less. I knew I could do it.

  In this confirmation test, in the gas sensor 1 using the sensor element 2 of the first embodiment, the steady-state power consumption for maintaining the sensor element 2 at the operating temperature was measured. Also, for comparison, in a gas sensor using a conventional sensor element, steady-state power consumption for maintaining the sensor element at an operating temperature was measured. As a result of the measurement, in the gas sensor 1 using the sensor element 2 according to the first embodiment, when the power consumption of the conventional gas sensor in the steady state is 100%, the power consumption of the conventional gas sensor is about 50%. %.

  In this confirmation test, in the gas sensor 1 using the sensor element 2 of Embodiment 3 in which the heat transfer member 38 overlaps the heat generating portion 341 in the stacking direction D, the heat transfer member 38 overlaps the heat generating portion 341 in the stack direction D. With respect to the gas sensor 1 using the sensor element 2 of the first embodiment, the activation time from the start of energization of the heating element 34 to the target operating temperature was measured. As a result of the measurement, the activation time of the gas sensor 1 using the sensor element 2 of the third embodiment is reduced to about 30% as compared with the activation time of the gas sensor 1 using the sensor element 2 of the first embodiment. It was confirmed that.

  The present invention is not limited to each embodiment, and it is possible to configure further different embodiments without departing from the gist thereof. Further, the present invention includes various modified examples, modified examples within an equivalent range, and the like.

DESCRIPTION OF SYMBOLS 1 Gas sensor 2 Sensor element 31, 31A, 31B Solid electrolyte body 311, 312, 311A, 311B, 312A, 312B Electrode 33A, 33B, 33C, 33D, 33E Insulator 34 Heating element 35 Gas chamber (gas space)
38 Heat transfer member

Claims (11)

In a gas sensor (1) including a plate-shaped sensor element (2),
The sensor element includes:
A solid electrolyte body (31) having oxygen ion conductivity;
A pair of electrodes (311, 312) provided on the surface of the solid electrolyte body;
An insulator (33A, 33B) laminated on the solid electrolyte body;
A gas space formed between the insulator at a position adjacent to the solid electrolyte body and accommodating one of the pair of electrodes and introducing a detection target gas (G) or a reference gas (A) ( 35, 36),
A heating section (341) that generates heat when energized and is disposed at a position where at least a part thereof overlaps the pair of electrodes in the stacking direction (D) of the solid electrolyte body and the insulator, and a pair of heating sections connected to the heating section. A heating element (34) having a lead portion (342) and embedded in the insulator forming the gas space;
The detection target gas is not permeated, and formed of a dense material of a metal oxide, and in a part of the gas space, between the insulator and the electrode in which the heating element is embedded, or the heating element is A heat transfer member sandwiched between the buried insulator, the electrode, and the solid electrolyte body, and for promoting heat transfer from the heat generating portion to the solid electrolyte body and the pair of electrodes; And a gas sensor comprising: In the gas space, the detection electrode (311), into which the detection target gas is introduced at a predetermined diffusion rate via the diffusion resistance part (32) and which is exposed to the detection target gas of the pair of electrodes, is disposed. Formed as a gas chamber (35);
The heating element is embedded in the insulator forming the gas chamber, facing the detection electrode,
The heat transfer member may be a part of the gas chamber, between the insulator in which the heating element is embedded and the detection electrode, or the insulator in which the heating element is embedded, the detection electrode, and the solid. The gas sensor according to claim 1, wherein the gas sensor is sandwiched between the electrolyte sensor and the electrolyte body. The gas space is formed as a reference gas duct (36) in which the reference gas is introduced and a reference electrode (312) of the pair of electrodes is exposed to the reference gas,
The heating element is buried in the insulator forming the reference gas duct, facing the reference electrode,
The heat transfer member may be a part of the reference gas duct, between the insulator embedded with the heating element and the reference electrode, or the insulator embedded with the heating element and the reference electrode and the solid. The gas sensor according to claim 1, wherein the gas sensor is sandwiched between the electrolyte sensor and the electrolyte body. In a gas sensor (1) including a long plate-shaped sensor element (2),
The sensor element includes:
A solid electrolyte body (31) having oxygen ion conductivity;
A detection electrode (311) provided on the first main surface (301) of the solid electrolyte body, which is exposed to the gas to be detected (G), at a position on the tip side in the longitudinal direction (L) of the sensor element;
A reference electrode (312), which is a second main surface (302) of the solid electrolyte body exposed to a reference gas (A) and is provided at a position on the distal end side in the long direction;
A first insulator (33A) laminated on the first main surface of the solid electrolyte body;
A heat-generating portion (341) which is arranged at a position where at least a part thereof overlaps the detection electrode and the reference electrode in the stacking direction (D) of the solid electrolyte body and the first insulator, and which generates heat by energization; A heating element (34) having a pair of leads (342) connected to a rear end side of the portion in the long direction and embedded in the first insulator;
A gas chamber (35) formed in a position of the first insulator adjacent to the first main surface of the solid electrolyte body and accommodating the detection electrode;
A diffusion resistance section (32) provided on the first insulator in communication with the gas chamber, for introducing the gas to be detected into the gas chamber at a predetermined diffusion rate;
A second insulator (33B) laminated on the second main surface of the solid electrolyte body;
A position adjacent to the second main surface of the solid electrolyte body in the second insulator, formed from a rear end opening (360) in the elongated direction to a position for accommodating the reference electrode; and A reference gas duct (36) through which the reference gas is introduced from the rear end opening;
The detection target gas is not permeated and is formed of a dense material of a metal oxide, and in a part of the gas chamber, between the first insulator and the detection electrode or between the first insulator and the detection. A heat transfer member (38) sandwiched between an electrode and the solid electrolyte body, and for promoting heat transfer from the heat generating portion to the solid electrolyte body, the detection electrode, and the reference electrode. Gas sensor. In a gas sensor (1) including a long plate-shaped sensor element (2),
The sensor element includes:
It has oxygen ion conductivity and has a first pump electrode (311A) and a second pump electrode (311B) provided at positions facing each other at the tip side position in the longitudinal direction (L) of the sensor element. 1 solid electrolyte body (31A);
A detection electrode (312A) that is disposed to face the first solid electrolyte body, has oxygen ion conductivity, and is provided at a position facing each other at a position on the distal end side in the longitudinal direction (L) of the sensor element; And a second solid electrolyte body (31B) having a reference electrode (312B) and
A first insulator (33C) laminated on a main surface of the first solid electrolyte body on which the first pump electrode is provided;
A second insulator (33D) sandwiched between a main surface of the first solid electrolyte body on which the second pump electrode is provided and a main surface of the second solid electrolyte body on which the detection electrode is provided; ,
A third insulator (33E) laminated on a main surface of the second solid electrolyte body on which the reference electrode is provided;
A heat generating portion (341) that generates heat by energization and is disposed at a position where at least a part thereof overlaps with each of the electrodes in a stacking direction (D) of each of the solid electrolyte bodies and each of the insulators; A heating element (34) having a pair of leads (342) connected to the rear end side in the longitudinal direction and embedded in the third insulator;
A gas chamber (35) formed so as to be surrounded by the first solid electrolyte body, the second solid electrolyte body, and the second insulator, and formed at a position accommodating the second pump electrode and the detection electrode;
A diffusion resistance section (32) provided on the second insulator in communication with the gas chamber, for introducing a gas to be detected into the gas chamber at a predetermined diffusion rate;
The detection target gas is not permeated, and is formed of a dense material of metal oxide, and in a part of the gas chamber, between the second pump electrode and the detection electrode, or between the second pump electrode and the second pump electrode. 1 is sandwiched between the solid electrolyte body, the detection electrode, and the second solid electrolyte body, and promotes heat transfer from the heat generating portion to the first solid electrolyte body, the first pump electrode, and the second pump electrode. A heat transfer member (38). The heat generating portion is formed by a meandering linear conductor portion,
The gas sensor according to claim 1, wherein the heat transfer member is arranged at a position overlapping a part of the heat generating portion in the stacking direction. A through hole (315) or a notch is formed in the electrode to penetrate the electrode in the stacking direction,
The heat transfer member is in contact with the solid electrolyte body through the through hole or the notch, and is in contact with an edge of the through hole or the notch in the electrode. A gas sensor according to claim 1. A through hole (315) or a notch is formed in the detection electrode to penetrate the detection electrode in the stacking direction,
The heat transfer member is in contact with the solid electrolyte body through the through hole or the notch, and is in contact with an edge of the through hole or the notch in the detection electrode. The gas sensor according to 2 or 4. The reference electrode is formed with a through hole (315) or a notch that penetrates the reference electrode in the stacking direction,
The heat transfer member is in contact with the solid electrolyte body through the through hole or the notch, and is in contact with an edge of the through hole or the notch in the reference electrode. 4. The gas sensor according to 3. The diffusion resistance section is provided at a distal end side portion of the first insulator in the elongated direction,
A cross-sectional area of a cross section of the heat transfer member orthogonal to the stacking direction is smaller than a cross-sectional area of a cross section of the detection electrode orthogonal to the stack direction.
5. The gas sensor according to claim 4, wherein the distal end portion of the detection electrode in the long direction is exposed to the detection target gas when the heat transfer member is not in contact.   In the heat transfer member, the distal end in the elongated direction at a position in contact with the detection electrode is separated from the distal end in the elongated direction of the detection electrode by 0.2 mm or more toward the base end in the elongated direction. The gas sensor according to claim 10.

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