JP5977414B2 - Gas sensor element and gas sensor - Google Patents

Description

  The present invention relates to a gas sensor element and a gas sensor including the same.

2. Description of the Related Art Conventionally, gas sensors that are attached to an exhaust passage of an internal combustion engine such as an automobile engine and detect NOx (nitrogen oxide) concentration in exhaust gas (measurement target gas) are known (see Patent Documents 1 and 2). In Patent Documents 1 and 2, as a gas sensor element constituting this gas sensor, a plate-shaped solid electrolyte body having oxygen ion conductivity, a first electrode provided on the front surface side or the back surface side of the solid electrolyte body, A first lead connected to the first electrode, a second electrode provided on the front surface side or the back surface side of the solid electrolyte body, and a measurement chamber (second chamber) disposed to face the first electrode A gas sensor element including a measurement chamber into which a measurement target gas is introduced and a reference oxygen chamber disposed to face the second electrode is described. In this gas sensor element, oxygen ions derived from NOx contained in the measurement target gas introduced into the measurement chamber move from the measurement chamber to the reference oxygen chamber through the solid electrolyte body, whereby oxygen derived from the NOx. A current corresponding to the concentration is configured to flow between the first electrode and the second electrode.

  In Patent Documents 1 and 2, the first electrode is formed to be porous in order to ensure oxygen pump performance. As a result, the first electrode becomes oxygen permeable. On the other hand, in order to improve electrical conductivity, it is preferable to increase the degree of filling per unit area, and for this purpose, the first leads are densely formed. As a result, the first lead is non-oxygen permeable.

Japanese Patent No. 4165552 JP 2010-122187 A

By the way, in FIG. 4 of patent document 1, the 1st electrode arrange | positioned in a measurement chamber (2nd chamber) is described as a 1st electrode. Further, as the first lead, a first lead connected to overlap the first electrode in the measurement chamber is described.
However, when the first electrode and the first lead are a combination of the oxygen permeable first electrode and the non-oxygen permeable first lead as described above, the following problems may occur. there were. That is, in the portion of the first electrode that overlaps the first lead (hereinafter also referred to as a connection portion), the oxygen pump performance may be reduced, and the detection accuracy for detecting the NOx concentration in the measurement target gas may be reduced. .

  On the other hand, in consideration of the above-mentioned problem, by extending a part of the first electrode to a position where the first electrode is not exposed to the measurement chamber (outside of the measurement chamber), the connection portion is moved to a position where it is not exposed to the measurement chamber (outside the measurement chamber) It is possible to arrange. Thereby, it can suppress that "the oxygen pump performance falls because a connection part is arrange | positioned in a measurement chamber, and the detection accuracy which detects NOx density | concentration in measurement object gas falls".

  However, even if the connecting portion is disposed at a position where it is not exposed to the measurement chamber, there is a possibility that the following problem may occur. In the gas sensor described above, a constant current is allowed to flow between the first electrode and the second electrode for a certain period of time before starting the normal control for detecting the NOx concentration in the measurement target gas. It is required to perform control to move (pump out) oxygen accumulated in the gas to the reference oxygen chamber through the measurement chamber. The NOx concentration (oxygen concentration derived from NOx) in the measurement target gas introduced from the outside without being affected by the oxygen accumulated inside the gas sensor element (specifically, inside the measurement chamber or the first electrode) This is to enable proper detection.

  However, if the connection portion of the first electrode is disposed at a position where it is not exposed to the measurement chamber (closed position), there is a possibility that oxygen accumulated (adsorbed) in the connection portion cannot be quickly pumped out. was there. For this reason, even after starting the normal control for detecting the NOx concentration in the measurement target gas, a large amount of oxygen remains in the connection portion, and during the normal control, this residual oxygen is little by little in the measurement chamber. There was a possibility that the phenomenon of moving over the time of the occurrence of. As described above, the residual oxygen in the connection portion is supplied to the measurement chamber over a long period of time, so that the sensor output (the first oxygen ion moves from the measurement chamber to the reference oxygen chamber through the solid electrolyte body after the control is started). It may take a long time for the current value flowing between the first electrode and the second electrode, and the corresponding NOx concentration) to stabilize. That is, it may take a long time before the NOx concentration in the measurement target gas can be properly detected.

  The present invention has been made in view of such a situation, and in a gas sensor element including an oxygen permeable first electrode and a non-oxygen permeable first lead connected thereto, oxygen of the first electrode is provided. An object of the present invention is to provide a gas sensor element that can appropriately detect the NOx concentration in the measurement target gas in a short time without deteriorating the pump performance, and a gas sensor including the gas sensor element.

A plate-shaped solid electrolyte body having oxygen ion conductivity, a first electrode of the solid electrolyte body surface or oxygen permeability provided on the back surface side of the non-oxygen permeability which is connected to the first electrode The first lead, the oxygen permeable second electrode provided on the front surface side or the back surface side of the solid electrolyte body, and a measurement chamber disposed opposite to the first electrode, wherein the measurement target gas is A measurement chamber to be introduced, and oxygen ions derived from NOx (nitrogen oxide) contained in the measurement target gas introduced into the measurement chamber are moved from the measurement chamber to the outside of the measurement chamber through the solid electrolyte body. In the gas sensor element configured to move in advance so that a current corresponding to the oxygen concentration derived from NOx flows between the first electrode and the second electrode, the first electrode has the measurement An exposed portion exposed to the chamber; Is disposed not to be exposed to serial measurement chamber position, a connecting portion connecting with the first lead, and a connecting portion including a portion that is disposed farthest from the measuring chamber in the first electrode A gas sensor element in which the entire connection portion is located in a region within a distance of 1.0 mm from the measurement chamber is preferable .

The gas sensor element includes an oxygen permeable first electrode and a non-oxygen permeable first lead connected to the first electrode. Among these, the 1st electrode has the exposed part exposed to a measurement chamber, and the connection part arrange | positioned in the position (outside of a measurement chamber) which is not exposed to a measurement chamber, and connects with a 1st lead | read | reed. Since this connection portion is formed by extending the first electrode in a direction away from the measurement chamber in order to connect to the first lead outside the measurement chamber, the position farthest from the measurement chamber among the first electrodes. The site | part arrange | positioned in is included .

  In the gas sensor element having such a configuration, conventionally, there is a possibility that oxygen accumulated (adsorbed) in the connection portion cannot be pumped out quickly. For this reason, even after starting normal control to detect the NOx concentration in the gas to be measured, a large amount of oxygen remains in the connection, and this residual oxygen gradually moves into the measurement chamber during normal control. There is a possibility that a phenomenon will occur. Due to this influence, it may take a long time from the start of control until the sensor output is stabilized. That is, it may take a long time before the NOx concentration in the measurement target gas can be properly detected.

  On the other hand, in the gas sensor element described above, the entire connection portion is disposed in a region whose distance from the measurement chamber is within 1.0 mm. As a result, oxygen accumulated in the connection portion can be quickly pumped out, and the time from the start of control to the stabilization of the sensor output can be shortened. That is, the NOx concentration in the measurement target gas can be appropriately detected in a short time.

In addition, in the gas sensor element described above, the first electrode is connected to the first lead at a position where it is not exposed to the measurement chamber. For this reason, unlike the above-mentioned Patent Document 1 (Japanese Patent No. 4165552), “the detection accuracy of detecting the NOx concentration in the measurement target gas due to the oxygen pump performance being lowered due to the connection portion being arranged in the measurement chamber” Can be suppressed.
In addition, as a “movement destination” where oxygen ions derived from NOx move from the measurement chamber to the outside of the measurement chamber, for example, an internal space of the gas sensor element different from the measurement chamber (for example, a reference oxygen chamber described later, another measurement chamber) And a space outside the gas sensor element (for example, a space in which the gas sensor element is in contact and the measurement target gas is circulated, and a space in which the gas sensor element is in contact and the atmosphere is circulated).

Furthermore, the gas sensor element may include a reference oxygen chamber disposed to face the second electrode, and the destination outside the measurement chamber may be the gas sensor element that is the reference oxygen chamber.
That is, a plate-shaped solid electrolyte body having oxygen ion conductivity, an oxygen permeable first electrode provided on the front surface side or the back surface side of the solid electrolyte body, and a non-oxygen permeable material connected to the first electrode A measurement chamber disposed opposite to the first electrode, a gas to be measured, and an oxygen permeable second electrode provided on the front or back side of the solid electrolyte body NOx (nitrogen oxide) -derived oxygen contained in the measurement target gas introduced into the measurement chamber, and a reference oxygen chamber disposed opposite to the second electrode. The ion is moved from the measurement chamber to the reference oxygen chamber through the solid electrolyte body so that a current corresponding to the oxygen concentration derived from NOx flows between the first electrode and the second electrode. In the gas sensor element The first electrode is an exposed portion that is exposed to the measurement chamber and a connection portion that is disposed at a position that is not exposed to the measurement chamber and is connected to the first lead. A gas sensor element comprising: a connection portion including a portion disposed at a position farthest from the measurement chamber; and the entire connection portion is located within a region having a distance of 1.0 mm or less from the measurement chamber. Good.
By using the gas sensor element described above, it is possible to appropriately detect the NOx concentration in the measurement target gas.

  Further, the gas sensor element according to any one of the above, further comprising an insulating layer formed on the front surface or the back surface of the solid electrolyte body, wherein a part of the first electrode and the first lead are on the insulating layer. The exposed portion of the first electrode includes a contact portion that contacts the solid electrolyte body through a through-hole penetrating the insulating layer, and the connecting portion of the first electrode includes the insulating portion. A gas sensor element connected to the first lead on the layer is preferable.

  In the gas sensor element described above, the exposed portion of the first electrode (the portion of the first electrode exposed to the measurement chamber) has a contact portion that contacts the solid electrolyte body through the through hole of the insulating layer. On the other hand, the first lead is formed on the insulating layer (this prevents contact with the solid electrolyte body). The connecting portion of the first electrode is connected to the first lead on the insulating layer. Therefore, in the gas sensor element described above, the connection portion of the first electrode is disposed at a position where it is not exposed to the measurement chamber and is not brought into contact with the solid electrolyte body.

  Thereby, in the above-mentioned gas sensor, only the contact portion of the first electrode can actually function as a sensitive portion, and the NOx concentration as the detection target can be detected with high accuracy. Since the first lead has different electrical characteristics from the first electrode, the gas concentration can be accurately detected when the first lead and a part of the connecting portion connected thereto are in contact with the solid electrolyte body. There are things you can't do.

One embodiment of the present invention is a plate-shaped solid electrolyte body having oxygen ion conductivity, an oxygen-permeable first electrode provided on the front surface side or the back surface side of the solid electrolyte body, and connected to the first electrode A non-oxygen permeable first lead, an oxygen permeable second electrode provided on the front surface side or the back surface side of the solid electrolyte body, and a measurement chamber disposed to face the first electrode. A measurement chamber into which the measurement target gas is introduced, and oxygen ions derived from NOx contained in the measurement target gas introduced into the measurement chamber are passed from the measurement chamber to the outside of the measurement chamber through the solid electrolyte body. In the gas sensor element configured to move between the first electrode and the second electrode by moving to the destination, a current corresponding to the oxygen concentration derived from NOx flows between the first electrode and the second electrode. It is not placed in the measurement chamber The gas sensor element has an insulating layer formed on the front surface or the back surface of the solid electrolyte body, and a part of the first electrode and the first lead are formed on the insulating layer, The first electrode includes a contact portion that contacts the solid electrolyte body through a through-hole penetrating the insulating layer, and a connection portion that is connected to the first lead in the measurement chamber and on the insulating layer. A gas sensor element.

  The gas sensor element includes an oxygen permeable first electrode and a non-oxygen permeable first lead connected to the first electrode. Of these, the entire first electrode is disposed in the measurement chamber (the entire front or back surface of the first electrode is exposed in the measurement chamber). Further, the connection portion is connected to the first lead in the measurement chamber.

  With such a configuration, it is possible to quickly draw out oxygen accumulated in the connection portion, and it is possible to shorten the time from the start of control until the sensor output is stabilized. That is, the NOx concentration in the measurement target gas can be appropriately detected in a short time.

  Moreover, in the gas sensor element described above, the connection portion of the first electrode is connected to the first lead on the insulating layer (this prevents contact with the solid electrolyte body). Therefore, even if the connection portion is arranged in the measurement chamber, the connection portion does not affect the oxygen pump performance of the first electrode (the oxygen pump performance of the first electrode is not deteriorated). For this reason, it can suppress that the detection precision which detects NOx density | concentration in measuring object gas falls.

Furthermore, the gas sensor element may include a reference oxygen chamber disposed to face the second electrode, and the destination outside the measurement chamber may be the gas sensor element that is the reference oxygen chamber.
That is, a plate-shaped solid electrolyte body having oxygen ion conductivity, an oxygen permeable first electrode provided on the front surface side or the back surface side of the solid electrolyte body, and a non-oxygen permeable material connected to the first electrode A measurement chamber disposed opposite to the first electrode, a gas to be measured, and an oxygen permeable second electrode provided on the front or back side of the solid electrolyte body And a reference oxygen chamber disposed to face the second electrode, and oxygen ions derived from NOx contained in the measurement target gas introduced into the measurement chamber are the solids. A gas sensor element configured such that a current corresponding to the oxygen concentration derived from NOx flows between the first electrode and the second electrode by moving from the measurement chamber to the reference oxygen chamber through the electrolyte body. In the first power Is arranged in the measurement chamber, and the gas sensor element has an insulating layer formed on the front surface or the back surface of the solid electrolyte body, and a part of the first electrode and the first lead are The first electrode is formed on the insulating layer, and the first electrode is connected to the solid electrolyte body through a through-hole penetrating the insulating layer, and the first electrode is formed in the measurement chamber and on the insulating layer. A gas sensor element having a connection portion connected to one lead is preferable.
By using the gas sensor element described above, it is possible to appropriately detect the NOx concentration in the measurement target gas.

Moreover, the other aspect of this invention is a gas sensor provided with one of the said gas sensor elements.
This gas sensor has any of the gas sensor elements described above. For this reason, in this gas sensor, it becomes possible to make it possible to appropriately detect the NOx concentration in the measurement target gas in a short time without deteriorating the oxygen pump performance of the first electrode.

It is sectional drawing of the gas sensor concerning a reference form and embodiment . It is a perspective view of the gas sensor element concerning a reference form and embodiment . It is BB sectional drawing of FIG. It is a perspective view which shows each layer which comprises a gas sensor element. It is an enlarged view of the E section of FIG. It is an enlarged view of the F section of FIG. It is a figure which shows the position of the connection part of Ip2-electrode, and is C arrow line view of FIG. It is a figure which shows the result of the performance evaluation test of a gas sensor element. It is another figure which shows the result of the performance evaluation test of a gas sensor element. Gas sensor element according to the embodiment, shows the position of the connection portion of Ip2- electrode.

( Reference form)
First, reference forms will be described with reference to the drawings.
FIG. 1 is a vertical cross-sectional view (a cross-sectional view cut along an axis AX) of a gas sensor 1 according to a reference embodiment. FIG. 2 is a perspective view of the gas sensor element 10 according to the reference embodiment. FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2 and shows the internal structure of the gas sensor element 10. FIG. 4 is a perspective view showing each layer constituting the gas sensor element 10 and shows the stacking direction (vertical direction in FIG. 4) in the stacking order. 5 is an enlarged view of a portion E in FIG. 4, and FIG. 6 is an enlarged view of a portion F in FIG.

  The gas sensor 1 includes a gas sensor element 10 that can detect the concentration of NOx (nitrogen oxide) in exhaust gas that is a measurement target gas, and is a NOx sensor that is used by being mounted on an exhaust pipe (not shown) of an internal combustion engine. (See FIG. 1). This gas sensor 1 includes a cylindrical metal shell 20 in which a screw portion 21 for fixing to an exhaust pipe is formed at a predetermined position on the outer surface. The gas sensor element 10 has an elongated plate shape extending in the direction of the axis AX, and is held inside the metal shell 20 (see FIGS. 1 and 2).

  More specifically, the gas sensor 1 includes a holding member 60 having an insertion hole 62 into which the rear end portion 10k (the upper end portion in FIG. 1) of the gas sensor element 10 is inserted, and six pieces held inside the holding member 60. Terminal members. In FIG. 1, only two terminal members (specifically, terminal members 75 and 76) out of the six terminal members are illustrated.

  A total of six electrode terminal portions having a rectangular shape in plan view are formed at the rear end portion 10k (right end portion in FIG. 2) of the gas sensor element 10. Specifically, electrode terminal portions 13, 14, and 15 are formed on the first surface 10a of the gas sensor element 10, and electrode terminal portions 16, 17, and 18 are formed on the second surface 10b. The above-described terminal members are in elastic contact with and electrically connected to the electrode terminal portions 13 to 18, respectively (see FIG. 1). Specifically, the element contact portion located on the tip side of each terminal member elastically contacts any one of the electrode terminal portions 13 to 18. For example, the element contact portion 75 b of the terminal member 75 is elastically contacted and electrically connected to the electrode terminal portion 14. Further, the element contact portion 76b of the terminal member 76 is elastically contacted and electrically connected to the electrode terminal portion 17 (see FIG. 1).

  Furthermore, different lead wires 71 are electrically connected to the six terminal members (terminal members 75, 76, etc.), respectively. Specifically, the lead wire 71 is electrically connected to the terminal member by gripping the core wire of the lead wire 71 by the lead wire gripping portion located at the rear end portion of the terminal member. For example, as shown in FIG. 1, the lead wire 71 is electrically connected to the terminal member 75 by gripping the core wire of the lead wire 71 by the lead wire gripping portion 77 of the terminal member 75. Further, the lead wire gripping portion 78 of the terminal member 76 grips the core wire of the other lead wire 71, whereby the other lead wire 71 is electrically connected to the terminal member 76.

  The metal shell 20 is a cylindrical member having a through hole 23 that penetrates in the direction of the axis AX. The metal shell 20 has a shelf 25 that constitutes a part of the through hole 23 in a form protruding radially inward. The metal shell 20 projects the front end portion 10s of the gas sensor element 10 to the outside of its front end side (downward in FIG. 1), and the rear end portion 10k of the gas sensor element 10 to the outside of its rear end side (upward in FIG. 1). The gas sensor element 10 is held in the through hole 23 in a state where the gas sensor element 10 is protruded to the inside.

  Further, an annular ceramic holder 42, two talc rings 43 and 44 formed by annularly filling talc powder, and a ceramic sleeve 45 are disposed inside the through hole 23 of the metal shell 20. Specifically, the ceramic holder 42, the talc rings 43 and 44, and the ceramic sleeve 45 are arranged in this order in the axial direction front end side (lower end side in FIG. 1) of the metal shell 20 in a state of surrounding the gas sensor element 10 in the radial direction. To the rear end side in the axial direction (upper end side in FIG. 1).

  A metal cup 41 is disposed between the ceramic holder 42 and the shelf 23 of the metal shell 20. A caulking ring 46 is disposed between the ceramic sleeve 45 and the caulking portion 22 of the metal shell 20. The caulking portion 22 of the metal shell 20 is crimped so as to press the ceramic sleeve 45 against the distal end side via the crimping ring 46.

  A metal (specifically, stainless steel) external protector 31 and an internal protector 32 having a plurality of holes are attached to the distal end portion 20b of the metal shell 20 by welding so as to cover the distal end portion 10s of the gas sensor element 10. ing. On the other hand, an outer cylinder 51 is attached to the rear end portion of the metal shell 20 by welding. The outer cylinder 51 has a cylindrical shape extending in the direction of the axis AX and surrounds the gas sensor element 10.

  The holding member 60 is a cylindrical member made of an insulating material (specifically alumina) and having an insertion hole 62 penetrating in the direction of the axis AX. In the insertion hole 62, the six terminal members (terminal members 75, 76, etc.) described above are arranged (see FIG. 1). At the rear end portion of the holding member 60, a flange portion 65 that protrudes radially outward is formed. The holding member 60 is held by the internal support member 53 in such a manner that the collar portion 65 contacts the internal support member 53. The inner support member 53 is held by the outer cylinder 51 by a caulking portion 51g that is caulked toward the radially inner side of the outer cylinder 51.

  An insulating member 90 is disposed on the rear end surface 61 of the holding member 60. The insulating member 90 is made of an electrically insulating material (specifically, alumina) and has a cylindrical shape. The insulating member 90 is formed with a total of six through holes 91 penetrating in the direction of the axis AX. In the through hole 91, the lead wire gripping portions (lead wire gripping portions 77, 78, etc.) of the terminal member described above are arranged.

  Further, an elastic seal member 73 made of fluororubber is arranged on the radially inner side of the rear end opening 51c located at the rear end portion in the axial direction (the upper end portion in FIG. 1) of the outer cylinder 51 (FIG. 1). reference). The elastic seal member 73 is formed with a total of six cylindrical insertion holes 73c extending in the axis AX direction. Each insertion hole 73 c is configured by an insertion hole surface 73 b (cylindrical inner wall surface) of the elastic seal member 73. One lead wire 71 is inserted through each insertion hole 73c. Each lead wire 71 extends to the outside of the gas sensor 1 through the insertion hole 73 c of the elastic seal member 73. The elastic seal member 73 is elastically compressed and deformed in the radial direction by caulking the rear end opening 51c of the outer cylinder 51 inward in the radial direction, whereby the insertion hole surface 73b and the outer peripheral surface 71b of the lead wire 71 are brought into close contact with each other. Thus, the space between the insertion hole surface 73b and the outer peripheral surface 71b of the lead wire 71 is sealed in a watertight manner.

  On the other hand, as shown in FIG. 3, the gas sensor element 10 includes plate-shaped solid electrolyte bodies 111, 121, 131 and insulators 140, 145 disposed therebetween, which are stacked in the stacking direction (FIG. 3). In the vertical direction). Further, in the gas sensor element 10, a heater 161 is laminated on the back surface 131 c side (the lower surface side in FIG. 3) of the solid electrolyte body 131. The heater 161 includes plate-like insulators 162 and 163 mainly composed of alumina, and a heater pattern 164 (mainly composed of Pt) embedded therebetween (see FIGS. 3 and 6). The heater pattern 164 includes a W-shaped heat generating portion 164d, and linear first lead portions 164b and second lead portions 164c connected to both ends of the heat generating portion 164d, respectively. The first lead portion 164b is electrically connected to the electrode terminal portion 16, and the second lead portion 164c is electrically connected to the electrode terminal portion 18 (see FIG. 6).

  The solid electrolyte bodies 111, 121, and 131 are made of zirconia, which is a solid electrolyte, and have oxygen ion conductivity. On the surface 111b side (the upper surface side in FIG. 3) of the solid electrolyte body 111, a porous Ip1 + electrode 112 is provided. A porous Ip1-electrode 113 is provided on the back surface 111c side (the lower surface side in FIG. 3) of the solid electrolyte body 111. The Ip1 + electrode 112 and the Ip1- electrode 113 are made of cermet containing Pt powder and ceramic powder, and have oxygen permeability.

In the present reference embodiment, as follows, to form a Ip1 + electrode 112 and Ip1- electrode 113. Specifically, first, 100 parts by weight of Pt powder, 14 parts by weight of ceramic powder, and 10 parts by weight of an organic binder (for example, ethyl cellulose) are mixed, and a predetermined amount of solvent is added to the mixture to form an electrode. Make a paste. Next, this electrode paste is applied to the front surface 111 b side and the back surface 111 c side of the solid electrolyte body 111. Thereafter, the organic binder is eliminated by heating, and the porous electrodes 112 and 113 are formed.

  As shown in FIG. 5, the Ip1 + lead 116 is connected to the connection part 112d of the Ip1 + electrode 112. The Ip1 + lead 116 is electrically connected to the electrode terminal portion 13. In addition, an Ip1-lead 117 is connected to the connection portion 113d of the Ip1-electrode 113. The Ip1-lead 117 is electrically connected to the electrode terminal portion 15. The Ip1 + lead 116 and the Ip1-lead 117 are formed of a cermet containing Pt powder and ceramic powder, but unlike the Ip1 + electrode 112 and the Ip1-electrode 113, they are densely formed. For this reason, the Ip1 + lead 116 and the Ip1-lead 117 are non-oxygen permeable.

In the present reference embodiment, as follows, to form a Ip1 + leads 116 and Ip1- lead 117. Specifically, first, 100 parts by weight of Pt powder, 18 parts by weight of ceramic powder, and 5 parts by weight of an organic binder (for example, ethyl cellulose) are mixed, and a predetermined amount of solvent is added to the mixture, thereby leading to lead. Make a paste. Next, this lead paste is applied to the front surface 111 b side and the back surface 111 c side of the solid electrolyte body 111. Thereafter, the organic binder is eliminated by heating, and leads 116 and 117 are formed.
By the way, the lead paste has an organic binder added in a small amount (about half the amount) compared to the above-mentioned electrode paste. In this way, by reducing the amount of the organic binder added that disappears by heating to form internal vacancies, dense leads 116 and 117 with few internal vacancies are formed.

  Further, a protective layer 115 made of alumina or the like is laminated on the surface side (the upper surface side in FIGS. 3 to 5) of the Ip1 + electrode 112 and the Ip1 + lead 116. A first porous body 114 exposed to the outside of the gas sensor element 10 is provided at a position facing the Ip1 + electrode 112 in the stacking direction in the protective layer 115. The first porous body 114 has gas permeability and is in contact with a part of the Ip1 + electrode 112. A portion of the Ip1 + electrode 112 that contacts the first porous body 114 is referred to as a contact portion 112b.

  The solid electrolyte body 111 and the electrodes 112 and 113 constitute an Ip1 cell 110 (first pump cell) (see FIG. 3). The Ip1 cell 110 has an atmosphere in contact with the electrode 112 (atmosphere outside the gas sensor element 10) and an atmosphere in contact with the electrode 113 (in a first measurement chamber 150 to be described later) according to a pump current Ip1 flowing between the electrodes 112 and 113. Pumping out and pumping oxygen (so-called oxygen pumping).

  The solid electrolyte body 121 is disposed so as to face the solid electrolyte body 111 in the stacking direction with the insulator 140 interposed therebetween. On the surface 121b side (upper surface side in FIG. 3) of the solid electrolyte body 121, a porous Vs-electrode 122 is provided. Further, a porous Vs + electrode 123 is provided on the back surface 121c side (the lower surface side in FIG. 3) of the solid electrolyte body 121. The Vs− electrode 122 and the Vs + electrode 123 are formed of cermet containing Pt powder and ceramic powder, and have oxygen permeability.

  As shown in FIG. 5, the Vs-lead 126 is connected to the connection portion 122 d of the Vs-electrode 122. The Vs-lead 126 is electrically connected to the electrode terminal portion 15. The Vs-lead 126 is formed of cermet containing Pt powder and ceramic powder, but unlike the Vs-electrode 122, it is formed densely. For this reason, the Vs-lead 126 is non-oxygen permeable. On the other hand, as shown in FIGS. 5 and 6, the Vs + lead 127 is connected to the Vs + electrode 123. The Vs + lead 127 is electrically connected to the electrode terminal portion 14. The Vs + lead 127 is formed of a cermet containing Pt powder and ceramic powder. Since the Vs + lead 127 is formed simultaneously with the Vs + electrode 123, the Vs + lead 127 is formed porous. For this reason, the Vs + lead 127 has oxygen permeability.

  A first measurement chamber 150 as an internal space of the gas sensor element is formed between the solid electrolyte body 111 and the solid electrolyte body 121 (see FIG. 3). The first measurement chamber 150 is an internal space in which the exhaust gas flowing through the exhaust passage is first introduced into the gas sensor element 10 and is connected to the outside of the gas sensor element 10 through the second porous body 151 having gas permeability. Communicate. The second porous body 151 is provided on the side of the first measurement chamber 150 as a partition from the outside of the gas sensor element 10, and limits the flow rate of exhaust gas per unit time into the first measurement chamber 150. (See FIGS. 2 and 5).

  On the rear end side (the right side in FIG. 3) of the first measurement chamber 150, as a partition between the first measurement chamber 150 and a second measurement chamber 160 described later, a flow rate of exhaust gas per unit time is limited. A three porous body 152 is provided.

  The solid electrolyte body 121 and the electrodes 122 and 123 constitute a Vs cell 120 (see FIG. 3). The Vs cell 120 mainly has an oxygen partial pressure difference between the atmospheres separated by the solid electrolyte body 121 (the atmosphere in the first measurement chamber 150 in contact with the electrode 122 and the atmosphere in the reference oxygen chamber 170 in contact with the electrode 123). In response, an electromotive force is generated.

  The solid electrolyte body 131 is disposed so as to face the solid electrolyte body 121 in the stacking direction with the insulator 145 interposed therebetween. On the surface 131b side (upper surface side in FIG. 3) of the solid electrolyte body 131, a porous Ip2 + electrode 132 and a porous Ip2-electrode 133 are provided. The Ip2 + electrode 132 and the Ip2- electrode 133 are made of cermet containing Pt powder and ceramic powder, and have oxygen permeability.

  As shown in FIG. 6, an Ip2 + lead 136 is connected to the Ip2 + electrode 132. The Ip2 + lead 136 is electrically connected to the electrode terminal portion 17. The Ip2 + lead 136 is formed of a cermet containing Pt powder and ceramic powder. Since the Ip2 + lead 136 is formed simultaneously with the Ip2 + electrode 132, the Ip2 + lead 136 is formed porous. For this reason, the Ip2 + lead 136 has oxygen permeability. On the other hand, the Ip2-lead 137 is connected to the connection part 133d of the Ip2-electrode 133. The Ip2-lead 137 is electrically connected to the electrode terminal portion 15. The Ip2-lead 137 is formed of a cermet containing Pt powder and ceramic powder, but unlike the Ip2-electrode 133, the Ip2-lead 137 is densely formed. For this reason, the Ip2-lead 137 is non-oxygen permeable.

  A reference oxygen chamber 170 as an isolated small space is formed at a position facing the Ip2 + electrode 132, more specifically, between the Ip2 + electrode 132 and the Vs + electrode 123 (see FIG. 3). In other words, the Ip2 + electrode 132 (second electrode) faces (is facing) the reference oxygen chamber 170 formed in the gas sensor element 10. The reference oxygen chamber 170 is constituted by an opening 145 b formed in the insulator 145. In the reference oxygen chamber 170, a ceramic porous body is disposed on the Ip2 + electrode 132 side.

A second measurement chamber 160 as an internal space of the gas sensor element is formed at a position facing the Ip2-electrode 133 in the stacking direction. In other words, the Ip2-electrode 133 (first electrode) faces (is facing) the second measurement chamber 160 formed in the gas sensor element 10. The second measurement chamber 160 includes an opening 145c that penetrates the insulator 145 in the laminating direction, an opening 125 that penetrates the solid electrolyte body 121 in the laminating direction, and an opening 141 that penetrates the insulator 140 in the laminating direction. It is comprised by.
The first measurement chamber 150 and the second measurement chamber 160 communicate with each other through a third porous body 152 having gas permeability. Therefore, the second measurement chamber 160 communicates with the outside of the gas sensor element 10 through the second porous body 151, the first measurement chamber 150, and the third porous body 152.

In the present reference embodiment, the solid electrolyte body 131 corresponds to a "solid electrolyte body". Further, Ip2- electrode 133 corresponds to the "first electrode". In addition, Ip2- lead 137 corresponds to the "first lead". Further, Ip2 + electrode 132 corresponds to the "second electrode". The second measurement chamber 160 corresponds to a “ measurement chamber”. The reference oxygen chamber 170 corresponds to the "destination measuring outdoor" and "reference oxygen chamber". The connecting portion 133d corresponds to a “ connecting portion”.

  The solid electrolyte body 131 and the electrodes 132 and 133 constitute an Ip2 cell 130 (second pump cell) for detecting the NOx concentration. The Ip2 cell 130 moves oxygen (oxygen ions) derived from NOx decomposed in the second measurement chamber 160 to a reference oxygen chamber 170 that is a destination outside the second measurement chamber 160 through the solid electrolyte body 131. . At this time, the lead 136 connected to the electrode 132 and the lead 137 connected to the electrode 133 have a current corresponding to the concentration of NOx contained in the exhaust gas (measurement target gas) introduced into the second measurement chamber 160. Flowing.

In this reference embodiment, an alumina insulating layer 138 is formed on the surface 131 b of the solid electrolyte body 131. Further, a part of the Ip2 + electrode 132 and the Ip2 + lead 136 are formed on the alumina insulating layer 138. Further, a part of the Ip2-electrode 133 and the Ip2-lead 137 are also formed on the alumina insulating layer 138 (this prevents contact with the solid electrolyte body 131). Further, the connection part 133 d of the Ip 2 -electrode 133 is connected to the lead 137 on the alumina insulating layer 138. Incidentally, the connecting portion 133d is located outside the second measuring chamber 160, and includes a site located farthest from the second measurement chamber 160 within the Ip2- electrode 133 (see FIG. 7) .

  In addition, the electrode 132 has a contact portion 132c that contacts the solid electrolyte body 131 through a through hole 138b that penetrates the alumina insulating layer 138 in the stacking direction. Further, the exposed portion 133b of the electrode 133 exposed to the second measurement chamber 160 has a contact portion 133c that contacts the solid electrolyte body 131 through a through hole 138c that penetrates the alumina insulating layer 138 in the stacking direction (see FIG. 3). ).

Therefore, in this reference embodiment, Ip2- the connecting portion 133d of the electrodes 133, as well as arranged in a position not exposed to the second measurement chamber 160, so as not to contact with the solid electrolyte body 131. As a result, only the contact portion 133c of the Ip2-electrode 133 can actually function as a sensitive portion, and the NOx concentration as the measurement target can be detected with high accuracy. In addition, since the electrical characteristics of the lead 137 and the electrode 133 are different, when the lead and a part of the connecting portion connected to the lead are in contact with the solid electrolyte body, the gas concentration is compared with the reference embodiment in which the lead 137 and the electrode 133 are not in contact The detection accuracy of is poor.

In the present reference embodiment, the exposed portion 133b corresponds to the "exposed portion". The alumina insulating layer 138 corresponds to an “ insulating layer”. The contact portion 133c corresponds to a “ contact portion”.

In this reference embodiment, the alumina insulating layer 118 is formed on the surface 111b of the solid electrolyte body 111 (see FIG. 3). Further, a part of the Ip1 + electrode 112 and the Ip1 + lead 116 are formed on the alumina insulating layer 118. Further, the contact portion 112b of the Ip1 + electrode 112 has a contact portion 112c that contacts the solid electrolyte body 111 through a through hole 118b that penetrates the alumina insulating layer 118 in the stacking direction.

  Further, an alumina insulating layer 119 is formed on the back surface 111 c of the solid electrolyte body 111. Further, a part of the Ip1-electrode 113 and the Ip1-lead 117 are formed on the alumina insulating layer 119. Further, the exposed portion 113b of the Ip1-electrode 113 exposed to the first measurement chamber 150 has a contact portion 113c that contacts the solid electrolyte body 111 through a through hole 119b that penetrates the alumina insulating layer 119 in the stacking direction.

Furthermore, in this reference embodiment, an alumina insulating layer 128 is formed on the surface 121 b of the solid electrolyte body 121. Further, a part of the Vs-electrode 122 and the Vs-lead 126 are formed on the alumina insulating layer 128. Furthermore, the exposed portion 122b of the Vs-electrode 122 exposed to the first measurement chamber 150 has a contact portion 122c that contacts the solid electrolyte body 121 through a through hole 128b that penetrates the alumina insulating layer 128 in the stacking direction.

  Further, an alumina insulating layer 129 is formed on the back surface 121 c of the solid electrolyte body 121. Further, a part of the Vs + electrode 123 and the Vs + lead 127 are formed on the alumina insulating layer 129. Furthermore, the Vs + electrode 123 has a contact portion 123c that comes into contact with the solid electrolyte body 121 through a through-hole 129b that penetrates the alumina insulating layer 129 in the stacking direction.

Further, in this preferred embodiment, Ip2- connecting portion 133d of the electrode 133 is disposed in a position not exposed to the second measurement chamber 160, and is connected to the Ip2- leads 137 outside the second measurement chamber 160 (FIG. 7 reference). For this reason, unlike the above-mentioned Patent Document 1 (Japanese Patent No. 4165552), “the detection accuracy of detecting the NOx concentration in the measurement target gas due to the oxygen pump performance being lowered due to the connection portion being arranged in the measurement chamber” Can be suppressed.

Here, the NOx concentration detected by the gas sensor 1 of this preferred embodiment will be briefly described.
The solid electrolyte bodies 111, 121, 131 of the gas sensor element 10 are heated and activated as the heater pattern 164 is heated. As a result, the Ip1 cell 110, the Vs cell 120, and the Ip2 cell 130 are operated.

  Before starting normal control for detecting the NOx concentration in the exhaust gas (measurement target gas), a constant current is allowed to flow between the electrode 132 and the electrode 133 for a certain period of time (for example, 20 seconds). Control is performed to move (pump out) oxygen accumulated in the interior of the gas chamber 10 to the reference oxygen chamber 170 through the second measurement chamber 160. The NOx concentration in the exhaust gas introduced from outside without being affected by the oxygen accumulated in the gas sensor element 10 (specifically, in the second measurement chamber 160 and the electrode 133) (oxygen concentration derived from NOx) This is to enable proper detection.

  Exhaust gas (measurement target gas) flowing in the exhaust passage (not shown) is introduced into the first measurement chamber 150 while being restricted by the second porous body 151. At this time, a weak current Icp flows through the Vs cell 120 from the electrode 123 side to the electrode 122 side. For this reason, oxygen in the exhaust gas can receive electrons from the electrode 122 in the first measurement chamber 150 on the negative electrode side, flows as oxygen ions in the solid electrolyte body 121, and moves into the reference oxygen chamber 170. To do. That is, when the current Icp flows between the electrodes 122 and 123, oxygen in the first measurement chamber 150 is sent into the reference oxygen chamber 170.

  When the oxygen concentration of the exhaust gas introduced into the first measurement chamber 150 is lower than a predetermined value, a current Ip1 is supplied to the Ip1 cell 110 so that the electrode 112 side becomes a negative electrode, and the gas sensor element 10 has an inside of the first measurement chamber 150. Pump oxygen into the water. On the other hand, when the oxygen concentration of the exhaust gas introduced into the first measurement chamber 150 is higher than a predetermined value, the current Ip1 is supplied to the Ip1 cell 110 so that the electrode 113 side becomes a negative electrode, and the gas sensor element 10 is supplied from the first measurement chamber 150. Pump out oxygen to the outside.

  In this way, the exhaust gas whose oxygen concentration is adjusted in the first measurement chamber 150 is introduced into the second measurement chamber 160 through the third porous body 152. NOx in the exhaust gas in contact with the electrode 133 in the second measurement chamber 160 is decomposed (reduced) into nitrogen and oxygen on the electrode 133 by applying a constant voltage Vp2 between the electrodes 132 and 133 and decomposed. Oxygen flows as oxygen ions through the solid electrolyte body 131 and moves into the reference oxygen chamber 170. At this time, the residual oxygen remaining in the first measurement chamber 150 is similarly moved into the reference oxygen chamber 170 by the Ip2 cell 130. As a result, a current derived from NOx and a current derived from residual oxygen flow through the Ip2 cell 130.

  Here, since the concentration of the residual oxygen remaining in the first measurement chamber 150 is adjusted to a predetermined value as described above, the current derived from the residual oxygen can be regarded as substantially constant, and is derived from NOx. The influence on the current fluctuation is small, and the current flowing through the Ip2 cell 130 is proportional to the NOx concentration. Therefore, the current Ip2 flowing through the Ip2 cell 130 can be detected, and the NOx concentration in the exhaust gas can be detected based on the current value.

Incidentally, in the gas sensor 1 of this preferred embodiment, the gas sensor element 10 is, as mentioned above, the oxygen permeability of the Ip2- electrode 133, the Ip2- connected to the electrode 133, non-oxygen permeable Ip2- a lead 137 I have. Among these, the electrode 133 has an exposed portion 133 b exposed to the second measurement chamber 160 and a connection portion 133 d that is disposed at a position not exposed to the second measurement chamber 160 and is connected to the lead 137. The connection portion 133d is formed by extending the electrode 133 in a direction away from the second measurement chamber 160 in order to connect the lead 137 to the outside of the second measurement chamber 160. It includes a portion arranged at a position farthest from the chamber 160 (see FIG. 7).

  Conventionally, in a gas sensor provided with such a gas sensor element, there is a possibility that oxygen accumulated in the connection portion of the Ip2-electrode cannot be quickly pumped out. Therefore, even after starting normal control to detect the NOx concentration in the measurement target gas, a large amount of oxygen remains (adsorbs) in the connection, and this residual oxygen is measured little by little during normal control. There is a possibility that a phenomenon of moving to the room over time may occur. As described above, due to the influence of residual oxygen in the connection portion being supplied into the measurement chamber for a long time, oxygen ions are transferred from the second measurement chamber 160 to the reference oxygen chamber 170 through the solid electrolyte body 131 after the control is started. There is a possibility that a long time is required until the current value flowing between the electrode 132 and the electrode 133 by the movement and the NOx concentration value corresponding thereto are stabilized. That is, it may take a long time before the NOx concentration in the measurement target gas can be properly detected.

In contrast, in the gas sensor 1 of this preferred embodiment, the gas sensor element 10, as shown in FIG. 7, the entire connection portion 133d of Ip2- electrode 133, a region distance is within 1.0mm from the second measurement chamber 160 It arrange | positions in A1 (area | region enclosed with the dashed-two dotted line K1 in FIG. 7). As a result, oxygen accumulated in the connection portion 133d can be quickly pumped out, and the time from the start of control of the gas sensor 1 (gas sensor element 10) to the stabilization of the sensor output can be shortened. It becomes. That is, the NOx concentration in the exhaust gas (measurement target gas) can be properly detected in a short time. This is clear from the result of the performance evaluation test described later.

(Embodiment)
Next, an embodiment of the present invention will be described. The gas sensor 201 of the present embodiment is different from the gas sensor 1 of the reference embodiment only in the gas sensor element, and the other parts are the same (see FIG. 1). Specifically, the gas sensor element 210 of the present embodiment is different from the gas sensor element 10 of the reference embodiment in the position of the Ip2-electrode with respect to the second measurement chamber, and is otherwise substantially the same. Therefore, here, it demonstrates centering on a different point from a reference form, and abbreviate | omits or simplifies description about the same point.

In the gas sensor element 10 of the reference form, as shown in FIG. 7, the connecting portion 133d of the Ip2-electrode 133 is located outside the second measurement chamber 160 and within a distance of 1.0 mm from the second measurement chamber 160. In the region A1 (region surrounded by a two-dot chain line K1 in FIG. 7).

On the other hand, in the gas sensor element 210 of this embodiment , as shown in FIG. 10, the Ip2-electrode 233 is arranged in the second measurement chamber 260. That is, the entire Ip2-electrode 233 including the connection portion 233d is arranged in the second measurement chamber 260. Thus, the entire Ip2-electrode 233 including the connection portion 233d is exposed in the second measurement chamber 260. Further, the Ip2-lead 237 is connected to the connection part 233d of the Ip2-electrode 233 in the second measurement chamber 260.

  By adopting such a configuration, it is possible to quickly pump out oxygen accumulated in the connection portion 233d of the Ip2-electrode 233, and shorten the time from the start of control until the sensor output is stabilized. It becomes possible. That is, the NOx concentration in the measurement target gas can be appropriately detected in a short time. This is clear from the result of the performance evaluation test described later.

  An alumina insulating layer 238 is formed on the surface 131b of the solid electrolyte body 131. The Ip2-electrode 233 has a contact portion 233c that contacts the solid electrolyte body 131 through the through hole 238c of the alumina insulating layer 238. (See FIG. 10). On the other hand, the Ip2-lead 237 is formed on the alumina insulating layer 238 (this prevents contact with the solid electrolyte body 131). Further, the connection part 233d of the Ip2-electrode 233 is connected to the Ip2-lead 237 on the alumina insulating layer 238 (this prevents the contact with the solid electrolyte body 131).

  Thereby, even if the connection part 233d is arranged in the second measurement chamber 260, the connection part 233d does not affect the oxygen pump performance of the Ip2-electrode 233 (decreasing the oxygen pump performance of the Ip2-electrode 233). Do not let them). For this reason, it can suppress that the detection precision which detects NOx density | concentration in measuring object gas falls. In addition, only the contact portion 233c of the Ip2-electrode 233 can actually function as a sensitive portion, and the NOx concentration that is the detection target can be detected with high accuracy.

In this embodiment , the Ip2-electrode 233 corresponds to a “first electrode” recited in the claims. The connecting portion 233d corresponds to a “connecting portion” recited in the claims. Further, the Ip2-lead 237 corresponds to a “first lead” recited in the claims. The alumina insulating layer 238 corresponds to the “insulating layer” recited in the claims. The contact portion 233c corresponds to a “contact portion” described in the claims.

(Performance evaluation test)
Next, the performance evaluation test of the gas sensor element (gas sensor) will be described.
First, gas sensor elements having different distances D1 (see FIG. 7) from the portion farthest from the second measurement chamber to the second measurement chamber in the connection portion of the Ip2-electrode were manufactured. The distance D1 is varied in the range of 0 to 2.0 mm at intervals of 0.5 mm. Next, a gas sensor (see FIG. 1) was produced using each gas sensor element. In this way, gas sensors having different distances D1 were prepared. The distance D1 = 0 mm of the gas sensor element corresponds to the gas sensor element 210 of the embodiment, a form in which the entirety arranged on the second measurement chamber 260 of the connecting portion 233d including Ip2- electrode 233.

  Next, each gas sensor was subjected to a performance evaluation test using the atmosphere (air) as a measurement target gas. Specifically, after activating the solid electrolyte body of each gas sensor, each gas sensor was controlled to measure the NOx concentration in the measurement target gas. First, a control is performed so that a constant current flows between the electrodes 132 and 133 for a certain time (for example, 20 seconds), and oxygen accumulated in the gas sensor element is moved to the reference oxygen chamber 170 through the second measurement chamber 160. (Pump out). In the present specification, this control is referred to as preliminary control.

  Thereafter, a constant voltage Vp2 is applied between the electrodes 132 and 133 to perform normal control for detecting the NOx concentration in the measurement target gas. By applying a constant voltage Vp2 between the electrodes 132 and 133, NOx in the measurement target gas in contact with the electrode 133 in the second measurement chamber 160 is decomposed (reduced) into nitrogen and oxygen on the electrode 133, and decomposed. The generated oxygen flows as oxygen ions in the solid electrolyte body 131 and moves into the reference oxygen chamber 170. As a result, a current derived from NOx flows through the Ip2 cell 130.

  In this test, the current Ip2 flowing through the Ip2 cell 130 was detected for each gas sensor from the start of control (preliminary control), and the NOx concentration (ppm) in the measurement target gas was measured based on the current value. The result is shown in FIG. In this test, since the atmosphere (air) is the measurement target gas, when the NOx concentration is stabilized at a value close to 0 ppm, the output is in a stable state, that is, the NOx concentration in the measurement target gas is set appropriately. It can be determined that it has been detected.

In FIG. 8, the data of the gas sensor in which the distance D1 is 0 mm is indicated by a thin solid line. Further, the data of the gas sensor in which the distance D1 is 0.5 mm is indicated by a broken line. Moreover, the data of the gas sensor which made distance D1 1.0mm are shown with the dashed-two dotted line. In addition, the data of the gas sensor in which the distance D1 is 1.5 mm is indicated by a one-dot chain line. Moreover, the data of the gas sensor which made distance D1 2.0 mm are shown by the thick continuous line.
For each gas sensor, the value of the NOx concentration detected after 180 seconds from the start of control was obtained. The result is shown in FIG. In FIG. 9, the value of the NOx concentration with respect to the distance D1 is shown.

  As shown in FIG. 8, when the distance D1 was made larger than 1.0 mm, it took a long time for the value of the NOx concentration to stabilize in the vicinity of 0 ppm. Specifically, when the distance D1 was 1.5 mm, it took about 400 seconds until the value of the NOx concentration was stabilized near 0 ppm. The value of the NOx concentration detected after 180 seconds from the start of control was about 1.8 ppm (see FIG. 9). When the distance D1 was 2.0 mm, it took about 600 seconds for the NOx concentration value to stabilize at around 0 ppm. Note that the value of the NOx concentration detected after 180 seconds from the start of control was about 4.0 ppm (see FIG. 9).

  The reason why it takes a long time for the output to stabilize as described above when the distance D1 is greater than 1.0 mm can be considered as follows. If the distance D1 is greater than 1.0 mm, it is considered that oxygen accumulated in the connection portion of the Ip2-electrode cannot be quickly pumped out even if preliminary control is performed. For this reason, even after starting the normal control for detecting the NOx concentration in the gas to be measured, a large amount of oxygen remains (adsorbs) in the connection portion, and this residual oxygen gradually increases during the normal control. 2 It is considered that a phenomenon of moving into the measurement chamber occurs. Due to this influence, it is considered that it takes a long time until the sensor output is stabilized after the control is started, that is, until it becomes possible to appropriately detect the NOx concentration in the measurement target gas.

  On the other hand, when the distance D1 was set to 1.0 mm or less, as shown in FIG. 8, the NOx concentration was stabilized around 0 ppm in about 180 seconds from the start of control. As shown in FIG. 9, when the distance D1 was 1.0 mm or less, the value of the NOx concentration detected after 180 seconds from the start of the control was almost 0 ppm.

  From the above results, by setting the distance D1 to be 1.0 mm or less, it is possible to quickly pump out the oxygen accumulated in the connection portion 133d, and the time from the start of control until the output becomes stable is obtained. It can be said that it can be shortened. That is, it can be said that the NOx concentration in the measurement target gas can be appropriately detected in a short time.

In the above, until the present invention has been described with reference to exemplary type condition, the present invention is not limited to the embodiments or the like described above, without departing from the spirit thereof, rather it may be modified as appropriate Nor.
For example, in the exemplary form state, the destination of oxygen has been NOx from decomposition in the second measurement chamber 160 (oxygen ions) to illustrate the gas sensor and the reference oxygen chamber 170. However, the present invention is not limited to such a gas sensor. The destination of the NOx-derived oxygen (oxygen ions) decomposed in the second measurement chamber 160 is different from that of the reference oxygen chamber 170. The present invention can also be applied to a gas sensor outside the measurement chamber 160 (for example, the first measurement chamber 150, a space where the measurement target gas outside the gas sensor element 10 circulates, and a space where the atmosphere outside the gas sensor element 10 circulates).

1,201 Gas sensor 10, 210 Gas sensor element 111, 121, 131 Solid electrolyte body 111b, 121b, 131b Surface 111c, 121c, 131c of solid electrolyte body Back surface 132 Ip2 + electrode (second electrode) of solid electrolyte body
133,233 Ip2-electrode (first electrode)
133b Exposed portion 133c, 233c Contact portion 133d, 233d Connection portion 136 Ip2 + Lead 137,237 Ip2-Lead (first lead)
138,238 Alumina insulating layer (insulating layer)
138c, 238c Through-hole 150 First measurement chamber 160, 260 Second measurement chamber (measurement chamber)
170 Reference oxygen chamber A1 Area whose distance from the second measurement chamber (measurement chamber) is within 1.0 mm

Claims (3)

A plate-like solid electrolyte body having oxygen ion conductivity;
An oxygen permeable first electrode provided on the front side or the back side of the solid electrolyte body;
A non-oxygen permeable first lead connected to the first electrode;
An oxygen permeable second electrode provided on the front or back side of the solid electrolyte body;
A measurement chamber disposed opposite to the first electrode, and a measurement chamber into which a measurement target gas is introduced,
The oxygen ions derived from NOx contained in the measurement target gas introduced into the measurement chamber move from the measurement chamber to a destination outside the measurement chamber through the solid electrolyte body, and thus according to the oxygen concentration derived from the NOx. In the gas sensor element configured to flow between the first electrode and the second electrode,
The first electrode is disposed in the measurement chamber,
The gas sensor element has an insulating layer formed on the front surface or the back surface of the solid electrolyte body,
A part of the first electrode and the first lead are formed on the insulating layer,
The first electrode is
A contact portion that contacts the solid electrolyte body through a through-hole penetrating the insulating layer;
A gas sensor element having a connection portion connected to the first lead in the measurement chamber and on the insulating layer. The gas sensor element according to claim 1 ,
A reference oxygen chamber disposed opposite to the second electrode,
The gas sensor element, wherein the destination outside the measurement chamber is the reference oxygen chamber. A gas sensor comprising the gas sensor element according to claim 1 .

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