JPH0222692Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an oxygen sensor for measuring oxygen concentration in a gas to be measured such as exhaust gas. More specifically, the present invention relates to an oxygen sensor that can measure air-fuel ratio and the like over a wide range and with great precision.

In order to improve the fuel efficiency and purify exhaust gas of automobile engines, a method has been proposed in which the air-fuel ratio of the intake air-fuel mixture is operated on the lean side, which is higher than the stoichiometric air-fuel ratio (excess air ratio λ = 1). There is a need for an oxygen sensor that can accurately measure air-fuel ratio.

One of the oxygen sensors for such use is the one published by Ford Corporation of the United States (for example, Japanese Patent Application Laid-Open No. 130649/1983).

This sensor consists of two plate-shaped oxygen ion conductive solid electrolyte sintered bodies with electrodes on both sides, one as an oxygen pump element and the other as an oxygen concentration battery element.
A cylindrical spacer made of a heat-resistant material with a small hole bored in the side wall is sandwiched, laminated, and bonded to form a chamber enclosed between the two plate-shaped elements and an oxygen diffusion hole. Then, the oxygen pump element for pumping out oxygen is energized, and the oxygen in the enclosed chamber is pumped to the output of the oxygen concentration battery element, for example, while allowing oxygen to flow through the hole to the outside atmosphere, ie, the atmosphere to be measured, by diffusion. In other words, the oxygen concentration in the gas to be measured can be determined electrically by pumping the oxygen so that the ratio of the oxygen concentration between indoors and outdoors is always constant. The method is to measure the This type of sensor is advantageous in terms of the temperature dependence of the sensor output on the ambient gas temperature because the oxygen pump element and the oxygen concentration battery element are provided separately. However, if more accuracy is required, it is necessary to add a heater to maintain the temperature of the sensor and the temperature of its surroundings at a substantially constant temperature. The above case had the disadvantage of poor thermal efficiency.

The purpose of the present invention is to solve the above-mentioned drawbacks, to provide an oxygen sensor that efficiently heats the sensor, has a simple structure, and can perform accurate measurements without affecting the measured value even by adding a heating resistor. This is what we provide.

That is, the gist of the present invention is to provide two zirconia oxygen ion conductive solid electrolyte plates for oxygen pump elements and oxygen concentration battery elements, each having heat-resistant metal layers for electrodes and lead wires on both sides. The shaped bodies are laminated and integrated by sandwiching an intermediate plate-shaped body having holes in the thickness direction, thereby distinguishing the tip side and the base side, and forming a flat enclosed chamber on the tip side and exposing the chamber to the outside world. A communication hole for communication is formed, and oxygen permeable walls of an oxygen pump element or an oxygen concentration battery element are formed on both walls in the thickness direction of the chamber, to which a voltage is applied or taken out from the source side via a lead wire. In an oxygen sensor, perforated plates or layers of electrically insulating ceramic are laminated in at least a portion in the thickness direction, and a heating resistor is embedded in or between the plates or layers and around the holes. The oxygen sensor is characterized by the following.

Next, explanation will be given with reference to the drawings. 1 to 3 show a first embodiment of the present invention. Figure 1 is the first
FIG. 3 shows an exploded perspective view of each component of the oxygen sensor of the example.

Here, 1 is an oxygen concentration battery element, 2 is an oxygen pump element, and 3 is a heating element. The oxygen concentration battery element 1 consists of a rectangular plate-like body of solid electrolyte,
Projections 1c are provided at opposing positions on each long side near the base side 1b. Front side 1a of battery element 1
Square-shaped electrodes 9 and 10 made of porous heat-resistant metal layers deposited using known thick film technology or thin film technology are provided on opposite sides of the device so as to sandwich the device. . A lead wire 9a made of a heat-resistant metal layer is provided in the shape of a band extending straight toward the base side 1b of the plate-like body from one of the two corners in the base side direction of one of the square electrodes 9. Similarly, 2 in the original direction of the other square electrode 10
Out of the two corners, a lead wire 10a is provided in a band shape extending straight toward the base side 1b of the plate-like body from the corner opposite to the electrode 9. The lead line 9a is on the base side 1b
A through hole 9d passes through the front and back of the plate-shaped body.
It is electrically connected to the take-out portion 9b on the opposite side through it. The lead line 10a is on the base side 1b
As a result, the extraction portions 9b and 10 of the two electrodes 9 and 10 are formed on the same surface.
b is arranged.

Like the battery element 1, the oxygen pump element 2 is also made of a rectangular plate-like solid electrolyte body, and protrusions 2c are provided at opposing positions on each long side near the base side 2b. On the tip side 2a of the pump element 2, electrodes 11 and 12 made of a porous heat-resistant metal layer are formed on opposing positions on the front and back surfaces of the pump element 2, sandwiching the element, using a known thick film technique or thin film technique. It is set up in a square shape. One square electrode 1
A lead wire 11a made of a heat-resistant metal layer is connected to the base side 2 of the plate-like body from one of the two corners in the direction of the base side of the plate-shaped body.
It is provided in a band shape extending straight to b. Similarly, out of the two corners of the other square electrode 12 in the original direction, the lead line 12
A is provided in a band shape extending straight toward the base side 2b of the plate-like body. The lead wire 12a has a through hole 12d penetrating the front and back of the plate-like body at the base side 2b.
It is electrically connected to the take-out portion 12b on the opposite side through the opening. The lead line 11a is on the original side 2
As a result, the extraction portions 11b of the two electrodes 11 and 12 are formed on the same surface.
b, 12b will be arranged.

The solid electrolyte forming each of the plate-shaped bodies of the battery element 1 and the pump element 2 needs to have the property of an oxygen ion conductor, and is composed of zirconia with 4 to 15 mol% of ittria, calcia, magnesia, etc. Solid solutions are typical, and other solid solutions include cerium dioxide, thorium dioxide, and hafnium dioxide, as well as perovskite-type oxide solid solutions.
A solid solution of a valent metal oxide or the like can be used as a solid electrolyte for an oxygen ion conductor. Here, zirconia partially stabilized with Y ₂ O ₃ was used.

Electrodes 9, 10, 1 formed on the surface of each plate-shaped body
1, 12, lead lines 9a, 10a, 11a, 1
2a, and take-out parts 9b, 10b, 11b,
The heat-resistant metal layer forming 12b is mainly made of Pt, Ru, Pd,
It consists of Rh, Ir, Au, Ag, etc., and is preferably formed by printing a paste containing the same base material. Here, the heat-resistant metal layer is formed by printing a paste made by adding 20% by weight of co-base powder to platinum powder and firing it at the same time as the element is sintered, and the thickness is approximately
The diameter was 15 μm, and the porosity was about 30%.

Next, the heating element 3 is made of an insulating plate-like material such as alumina or spinel, and protrusions 3c are provided at opposing positions on each of its long sides. The length from this protrusion 3c to the tip side 3a is the same as the other two elements, but the length from the protrusion 3c to the base side 3b is the same as the other two elements.
Unlike the two elements, it is formed to be somewhat long. However, the widths are all the same as the other two elements. On the front side 3a of the heating element 3, electrodes 9, which are provided on the battery element 1 and the pump element 2, are provided.
Holes 8 are punched out in the thickness direction at sizes and locations corresponding to positions 10, 11, and 12. A portion of the plate-shaped body surrounding the hole 8 is cut out to form a communicating hole 8a to the hole 8 from the outside. A heating resistor 13 is arranged in a wavy or linear manner on one surface of the heating element plate around the hole 8, and is connected to a lead wire 14b at opposite ends 13a and 13b of the heating resistor across the communicating hole 8a. ing. 2
The lead wires 14b are led from the heating resistor end 13a on the heating element tip side 3a to the heating element base side 3b, and their respective tips form a takeout portion 14c. The heating resistor 13 and the lead wire 14
b and the lead-out portion 14c are made of a heat-resistant metal layer, the heat-generating resistor 13 is made of a paste of a heat-resistant, oxidation-resistant metal material such as Pt, Rh, and the lead wire 14b and the lead-out portion 14c are made of a paste of a heat-resistant, oxidation-resistant metal material such as Pt, Ru, Pd, Rh. ,Ir,
It is formed by printing pastes such as Au and Ag. Here, for the heat-resistant metal layer, a paste was used in which 20% by weight of co-base powder was added to platinum powder.

In this way, the heating resistor 13 and the lead wire 14b
and on the surface where the take-out portion 14c is formed,
Furthermore, an insulating coat 6 of a non-conductive material is applied to provide insulation. The material of this insulating coat is preferably alumina or spinel, which is the same as the material of the heating element plate, because it has good adhesive properties due to sintering and does not cause thermal distortion. The thickness of the coat is typically set at 50μ.

The elements 1, 2, and 3 of the first embodiment described above are preferably placed in the order of the battery element 1, the heating element 3 coated with the coating 6, and the pump element 2 so that their front sides coincide with each other in an unfired state. The protrusions 1c, 2c, and 3c are laminated and pressed together, and the locking pieces 4 and 5 are laminated and pressed so as to sandwich these parts.
By firing this laminate in an air atmosphere, an oxygen sensor as shown in FIGS. 2 and 3 is formed.

Note that after the heating element 3 is obtained as a sintered body, a battery element and a pump element, which are also obtained as sintered bodies, are bonded together by applying a heat-resistant inorganic adhesive or glass frit paste, and heat-treated. Alternatively, a method of laminating and integrating them may be adopted, and in that case, a high melting point metal material such as W (tungsten) can also be used as the heating resistor or the lead wire.

FIG. 2 shows a sectional view of the oxygen sensor of the first embodiment, and FIG. 3 shows a perspective view.

The oxygen sensor of the above embodiment integrated in this way has the electrode 9 (5 mm x 5 mm) of the battery element 1 on the front side.
mm), a chamber 16 (5 mm x 5mm x thickness 0.5mm),
A heating resistor is provided around the chamber 16 (around the hole 8), and one of the heating elements 3 stacked in the center is placed on the base side.
The part 9 protrudes to take out each element.
b, 10b, 11b, 12b, 14c, and 14c are exposed, and has a locking part 17 for assembling the sensor probe from the center toward the base side.

In the sensor of this embodiment, the platinum heating resistor placed around the chamber 16 is 12V 10watt.
It was possible to maintain sufficient capacity as a sensor for measuring oxygen partial pressure in exhaust gas from automobile engines. Also, the current of the oxygen pump element is
Enclosed chamber 16 varying from 0.02mA to 3mA
When oxygen was pumped out from the internal atmosphere, the oxygen concentration in the external measured gas ranged from approximately 0.05 to 10% under the condition that the output voltage of the oxygen concentration cell element was constant at 20 millivolts. The correspondence between the two was linear on a logarithmic scale. Note that the temperature of the sensor was maintained at approximately 800°C.

In the oxygen sensor of the first embodiment described above, the heating element 3 incorporated in the sensor efficiently heats the entire sensor, and good temperature compensation is achieved. Moreover, since the heating resistor 13 through which the heating current flows and its lead wire 14b are insulated from other elements by the heating element itself and the insulating material covering it, the current of the heating element is It does not flow to the element and does not adversely affect measurement accuracy. Further, the communicating hole 8 has a vertical width equal to the thickness of the chamber 16, and serves to prevent performance deterioration due to clogging of the hole 8 during use and to improve responsiveness.

Next, FIG. 4 shows a second embodiment. Here, 21 is a battery element, 22 is a pump element, 23 is a heating element, and 26 is an insulating plate. The battery element 21 is made of a rectangular plate-like solid electrolyte. Battery element 2
On the front side 21a of 1, square electrodes 29 and 30 made of heat-resistant metal layers are provided at opposing positions on the front and back surfaces of the device so as to sandwich the element therebetween. A lead wire 29a made of a heat-resistant metal layer is provided from one of the two corners of one of the square electrodes 29 in the direction toward the base side in a band shape extending straight toward the base side 21b of the plate-like body. Similarly, a lead line 30a is provided in a band shape extending straight toward the base side 21b of the plate-like body from the corner opposite to the inner electrode 29 of the two corners in the base side direction of the other square electrode 30. Lead line 29
a is electrically connected to a take-out portion 29b on the opposite side of the base side 21b through a through hole 29d penetrating the front and back sides of the plate-like body. The lead wire 30a forms a lead-out portion 30b at the base side 21b, and as a result, two electrodes 29, 30 are formed on the same surface.
The extraction portions 29b and 30b will be provided.

Like the battery element 21, the oxygen pump element 22 is also made of a rectangular plate-like solid electrolyte. Pump element 2
On the front side 22a of 2, square electrodes 31 and 32 made of heat-resistant metal layers are provided at opposing positions on the front and back surfaces of the element so as to sandwich the element therebetween. A lead wire 31a made of a heat-resistant metal layer is provided in the shape of a band extending straight toward the base side 22b of the plate-like body from one of the two corners of the square electrode 31 in the base side direction. Similarly, out of the two corners of the other square electrode 32 in the direction toward the base, a lead wire 32a is provided in a band shape extending straight from the corner opposite to the electrode 31 toward the base side 22b of the plate-like body. Lead line 3
2a is electrically connected to a take-out portion 32b on the opposite side of the base side 22b through a through hole 32d penetrating the front and back sides of the plate-like body. The lead wire 31a forms a lead-out portion 31b at the base side 22b, and as a result, two electrodes 31, 3 are formed on the same surface.
Two take-out portions 31b and 32b are provided.

As the solid electrolyte forming each plate-like body of the battery element and pump element of this embodiment, the same oxygen ion conductive solid electrolyte as that of the first embodiment is used.

Electrodes 29, 30 provided on the surface of each plate-shaped body,
31, 32, lead lines 29a, 30a, 31
a, 32a and take-out parts 29b, 30b, 3
1b and 32b are formed using the same materials and using the same method as in the first embodiment.

Next, the heating element 23 is made of an insulating plate-like material such as alumina or spinel. Its width is similar to the other two elements, but its length is longer than the other elements to some extent. A hole 28 is punched out in the thickness direction on the front side 23a of the heating element 23, with a size and location corresponding to the positions of the electrodes 29, 30, 31, 32 provided on the battery element 21 and pump element 22. is provided. A heating resistor 33 is arranged in a wavy or linear manner on one surface of the heating element plate around the hole 28, and both ends of the resistor 33 are connected to the lead wire 3 at a position near the hole 28 and closer to the base side.
Connected to 4b. The two lead wires 34b are led to the heating element source side 23b, and their respective tips form a take-out portion 34c. The heating resistor 33, the lead wire 34b and the take-out portion 3
4c is made of the same heat-resistant metal layer as in the first embodiment;
formed in a similar manner.

Next, the insulating plate 26 is made of an insulating plate-like material such as alumina or spinel. Its width is the same as the three elements, and its length is the same as the battery element 21.
On the front side of this insulating plate 26 is the pump element 22.
A hole 37 is punched out in the thickness direction, corresponding to the position and size of the electrode 32 and the hole 28 of the heating element 23 provided in the heating element 23 . The insulating plate 2
Three parts of the area around the hole 37 of No. 6 are cut out, and communication holes 37a, 37 are formed to connect the hole 37 from the outside.
b, 37c are formed. This means that the insulating plate 26 is composed of three pieces 26a, 26b, and 26c.

More preferably, the above elements and insulating plates are laminated and crimped in the order of battery element 21, heating element 23, insulating plate 26 and pump element 22 so that their front sides coincide with each other at the stage of green molded product, By firing and integrating this laminate, an oxygen sensor as shown in FIG. 5 is formed.

FIG. 5 shows a cross-sectional view in the longitudinal direction of the oxygen sensor of the second embodiment. The oxygen sensor thus laminated and integrated has the electrode 29 (5) of the battery element 21 on the front side.
mm x 5 mm), electrode 32 of pump element 22 (5 mm x
5 mm), the inner surface 35 of the hole 28 of the heating element 23 and the inner surface 38a, 38b, 38 of the hole 37 of the insulating plate 26
communication holes 37a, 37b, 37c
(each 1 mm x 0.5 mm x length 1 mm) has a chamber 36 (5 mm x 5 mm x thickness 1 mm) that communicates with the outside,
A heating resistor is provided around the chamber 16 (around the hole), and a part of the stacked heating elements 23 protrudes from the base side, and a take-out portion 29 of each element is formed.
b, 30b, 31b, 32b, 34c, and 34c are exposed.

In the above example, the current of the oxygen pump element is
Chamber 5 enclosed by varying from 0.025mA to 5mA
When oxygen is pumped out from the atmosphere inside 6, the oxygen concentration in the external gas to be measured under the condition that the output voltage of the oxygen concentration battery element is constant at 20 mV is approximately
It ranged from 0.05 to 10%. The correspondence between the two was linear on a logarithmic scale. The temperature of the sensor was maintained at approximately 800°C.

In the oxygen sensor of the second embodiment described above, the heating element 23 incorporated in the sensor efficiently heats the entire sensor, thereby achieving good temperature compensation, and the heating resistor 33 through which the heating current flows.
Since the lead wire 34b is insulated from other elements by the heating element itself and the insulating plate 26, the current of the heating device does not flow to other elements, and measurement accuracy is not adversely affected. . Furthermore, since the communication holes are open in three directions, it is possible to uniformly diffuse oxygen between the chamber 36 and the outside air, improving responsiveness and enabling more accurate measurement.

In the stacked assembly of the oxygen sensor of the second embodiment, the insulating plate may be assembled using three pieces separated from the beginning, but as shown in FIG. form and the other 3
It is easier to manufacture the oxygen sensor by cutting off the edges 26d of the green sheet after laminating and assembling the elements.

Next, FIG. 7 shows a third embodiment. Here, 41 is a battery element, 42 is a pump element, 43 is a heating element, 46 is an insulating plate, and 59 is an intermediate plate-shaped body.

The battery element 41 is made of a rectangular plate-like solid electrolyte. On the front side 41a of the battery element 41, square electrodes 49 and 50 made of heat-resistant metal layers are provided at opposing positions on the front and back surfaces of the battery element 41 so as to sandwich the element. 2 in the original direction of one square electrode 49
A lead wire 49a made of a heat-resistant metal layer is provided in a band shape extending straight toward the base side 41b of the plate-like body from one of the four corners. Similarly, among the two corners of the other square electrode 50 in the original direction, the electrode 49
A lead line 50a is provided in a band shape extending straight toward the base side 41b of the plate-like body from the opposite corner. The lead wire 49a passes through a through hole 49d penetrating the front and back sides of the plate-like body at the base side 41b.
It is electrically connected to the take-out portion 49b on the opposite side. The lead wire 50a forms a take-out portion 50b on the base side 41b, and as a result, two wires are formed on the same surface.
Take-out portions 49b, 50b of two electrodes 49, 50
will be set up.

Like the battery element 41, the pump element 42 is also made of a rectangular plate-like solid electrolyte. Pump element 42
On the front side 42a, electrodes 5 made of heat-resistant metal layers are placed at opposite positions on the front and back surfaces of the element so as to sandwich the element.
1 and 52 are provided in a square shape. A lead wire 51a made of a heat-resistant metal layer is provided in a band shape extending straight toward the base side 51b of the plate-like body from one of the two corners in the base side direction of one square electrode 51. Similarly, out of the two corners of the other square electrode 52 in the direction toward the base, a lead wire 52a is provided in a band shape extending straight from the corner opposite to the electrode 51 toward the base side 42b of the plate-like body. Lead line 52
A is electrically connected to a take-out portion 52b on the opposite side of the base side 42b through a through hole 52d penetrating the front and back sides of the plate-like body. The lead wire 51a forms a lead-out portion 51b at the base side 42b, and as a result, two electrodes 51 and 52 are formed on the same surface.
The extraction portions 51b and 52b will be provided.

As the solid electrolyte forming each plate-like body of the battery element and pump element of this embodiment, the same oxygen ion conductive solid electrolyte as that of the first embodiment is used.

Electrodes 49, 50 provided on the surface of each plate-shaped body,
51, 52, lead lines 49a, 50a, 51
a, 52a and take-out parts 49b, 50b, 5
1b and 52b are formed using the same material and using the same method as in the first embodiment.

Next, the heating element 43 is made of an insulating plate-like material such as alumina or spinel. Its width and length are similar to the other two elements. Tip side 4 of heating element 43
3a includes electrodes 49, 50, 51, 5 provided on the battery element 41 and pump element 42.
A hole 48 is punched out in the thickness direction at a size and location corresponding to No. 2. A heating resistor 53 is arranged in a wavy or linear manner on one surface of the heating element plate around the hole 48, and both ends of the resistor 53 are connected to the lead wire 5 at a position near the hole 48 and closer to the base side.
Connected to 4b. The two lead wires 54b are further guided from the heating element source side 43b to the end surface 43c, and their respective tips form a take-out portion 54c at the end surface 43c. The heating resistor 5
3. The lead wire 54b and the lead-out portion 54c were made of the same heat-resistant metal layer as in the first embodiment, and were formed by the same method.

Next, the insulating plate 46 is made of an insulating plate-like material such as alumina or spinel. Its width and length are the same for the three elements. The front side 46 of this insulating plate 46
A hole 57 is punched out in the thickness direction in correspondence with the position and size of the electrode 52 provided in the pump element 42 and the hole 48 of the heating element 43.

Next, the intermediate plate-like member 59 is made of a plate-like member made of a solid electrolyte such as zirconia, which is the same as the pump element. Its width and length are the same as the three elements and the insulating plate 46. Like the insulating plate 46, this intermediate plate-like body 59 is provided with a hole 61 of the same size punched out in the thickness direction at the same position on the front side thereof. Three portions of the intermediate plate-like body 59 surrounding the hole 61 are cut out to form communication holes 61a, 61b, and 61c that connect the hole 61 from the outside. As a result, the intermediate plate-like body 59 has three pieces 59a, 59
b, 59c.

More preferably, each of the above-mentioned elements, insulating plate, and intermediate plate-like body are arranged so that the battery element 41, the heating element 4
3. The insulating plate 46, the intermediate plate-shaped body 59, and the pump element 42 are laminated and pressed in this order, and this laminated body is fired and integrated to form an oxygen sensor as shown in FIG.

FIG. 8 shows a cross-sectional view in the longitudinal direction of the oxygen sensor of the third embodiment. The whole of the integrated oxygen sensor formed into a rectangular parallelepiped has an electrode 49 (5 mm x 5 mm) of the battery element 41, an electrode 52 (5 mm x 5 mm) of the pump element 42, and a heating element 43 on the front side.
an inner surface 55 of the hole 48 of the insulating plate 46, an inner surface 58 of the hole 57 of the insulating plate 46, and an inner surface 60 of the hole 61 of the intermediate plate-like body 59.
a, 60b, 60c, and communication holes 61a,
61b, 61c (each 1mm x 0.5mm x length 1
It has a chamber 56 (5 mm x 5 mm x thickness 1.5 mm) that communicates with the outside through a hole (periphery of the hole).
A heating resistor is placed on the side, and a take-out portion 49 is placed on the base end.
b, 50b, 51b, and 52b, and has a take-out portion 54c for the heating element 43 on the end face. However, in the cross-sectional view of FIG.
An example is shown in which the heating element is provided not only on the end face 43c of the heating element but also on the end face of the insulating plate 46.

In the embodiment described above, the correspondence between the current of the oxygen pump element and the partial pressure of oxygen in the gas to be measured is the same as in the case of the second embodiment.

In the oxygen sensor of the third embodiment described above, the entire sensor is efficiently heated by the heating element 43 incorporated in the sensor, thereby achieving good temperature compensation. Furthermore, the heating resistor 53 through which the heating current flows and its lead wire 54b are completely buried in the heating element itself and the insulating plate 46, and are electrically insulated from other elements, so that the current of the heating element is It does not flow to other elements, does not adversely affect measurement accuracy, and improves durability. Further, since the communication holes are open in three directions, it is possible to uniformly diffuse oxygen between the chamber 56 and the outside air, thereby enabling more accurate measurement.

Next, FIG. 9 shows a fourth embodiment. Here, 71 is a battery element, 72 is a pump element, 73 is a heating element, 76 is a protection plate that protects the heating resistor, and 89 is an intermediate plate.

The battery element 71 is made of a rectangular plate-like solid electrolyte. At the front end 71a of the battery element 71, square electrodes 79 and 80 made of heat-resistant metal layers are provided at opposing positions on the front and back surfaces of the battery element 71 so as to sandwich the element. 2 in the original side direction of one square electrode 79
A lead wire 79a made of a heat-resistant metal layer is provided in a band shape extending straight toward the base side 71b of the plate-like body from one of the four corners. Similarly, among the two corners of the other square electrode 80 in the original direction, the electrode 79
A lead line 80a is provided in a band shape extending straight toward the base side 71b of the plate-like body from the opposite corner. The lead wire 79a is connected to the base side 71b through a through hole 79d passing through the front and back of the plate-like body.
It is electrically connected to the take-out portion 79b on the opposite side. The lead line 80a forms a take-out part 80b on the base side 71b, and as a result, two lines are formed on the same surface.
Take-out portions 79b, 80b of two electrodes 79, 80
will be set up.

Like the battery element 71, the pump element 72 is also made of a rectangular plate-like solid electrolyte. Pump element 72
At the tip 72a, there are electrodes 8 made of heat-resistant metal layers at opposite positions on the front and back surfaces of the element so as to sandwich the element.
1 and 82 are provided in a square shape. A lead wire 81a made of a heat-resistant metal layer is provided from one of the two corners of one square electrode 81 in the direction toward the base side in a band shape extending straight toward the base side 81b of the plate-like body. Similarly, out of the two corners of the other square electrode 82 in the direction toward the base, a lead line 82a is provided in a band shape extending straight from the corner opposite to the electrode 81 toward the base side 72b of the plate-like body. Lead line 82
a is electrically connected to a take-out portion 82b on the opposite side of the base side 72b through a through hole 82d penetrating the front and back sides of the plate-like body. The lead wire 81a forms a lead-out portion 81b at the base side 72b, and as a result, two electrodes 81 and 82 are formed on the same surface.
The extraction portions 81b and 82b will be provided.

As the solid electrolyte forming each plate-like body of the battery element and pump element of this embodiment, the same oxygen ion conductive solid electrolyte as that of the first embodiment is used.

Electrodes 79, 80 provided on the surface of each plate-shaped body,
81, 82, lead lines 79a, 80a, 81
a, 82a and take-out parts 79b, 80b, 8
1b and 82b are formed using the same materials and using the same method as in the first embodiment.

Next, the heating element 73 is made of an insulating plate-like material such as alumina or spinel. Its width is similar to the other two elements, but its length is shorter than the other elements to some extent. Front side 73 of heating element 73
A hole 78 is punched out in the thickness direction at a size and location corresponding to the electrode 81 provided in the pump element 72. hole 78
A heating resistor 83 is placed on one side of the heating element plate around the heating element plate.
are arranged in a wavy or linear manner, and both ends of the resistor 83 are connected to a lead wire 84b near the hole 78 and closer to the base side. Two lead lines 8
4b are led to the heating element source side 73b, and their respective tips form a take-out portion 84c. The heating resistor 83, the lead wire 84b, and the lead-out portion 84c were made of the same heat-resistant metal layer as in the first embodiment, and were formed by the same method.

Next, the intermediate plate 89 is made of an insulating plate-like material such as alumina or spinel, or a plate-like material made of the same material as the battery element or the pump element. Its width and length are the same as the battery element 71 and the pump element 72. On the front side 89a of this intermediate plate 89, corresponding to the position and size of the electrode 79 provided on the battery element 71 and the electrode 82 of the pump element 72,
A hole 91 punched in the thickness direction is provided.
A portion of the intermediate plate 89 surrounding the hole 91 is cut out in one to several pieces (in this case, one piece) at its tip to form a communicating hole 91a to the hole 91 from the outside.

Next, the protection plate 76 is made of the same insulating plate-like material as the heating element 73, such as alumina or spinel. Its width is the same as the other three elements and the insulating plate 89, and its length is even shorter than the heating element 73. A hole 87 punched out in the thickness direction is provided on the front side 76a of the protective plate 76, corresponding to the position and size of the hole 78 of the heating element 73.

The above elements 71, 72, 73, intermediate plate 89, and protective plate 76 are preferably unfired, and the battery element 71, intermediate plate 89, pump element 72, and heated Element 7
3, and the protective plates 76 are laminated and crimped in this order.
By firing this laminate, an oxygen sensor as shown in FIG. 10 is formed.

FIG. 10 shows a cross-sectional view in the long axis direction of the oxygen sensor of the fourth embodiment. The oxygen sensor of the fourth embodiment integrated in this way has an electrode 79 (5 mm x 5 mm) of a battery element 71, an electrode 82 (5 mm x 5 mm) of a pump element 72, and a hole 91 of an intermediate plate 89 on the front side. The communication hole 91a (2 mm x 0.5 mm
A chamber 92 (5 mm x 1 mm long) communicates with the outside.
5 mm x thickness 0.5 mm), and the other electrode 81 of the pump element 72 is the bottom surface, and the flat square is surrounded by the inner surface 85 of the hole 78 of the heating element 73 and the inner surface 88 of the hole 87 of the protection plate 76. A heating resistor is provided around the hole 78, and take-out portions 79b and 82b are provided at the base end of the stacked body of the battery element 71, the intermediate plate 89, and the pump element 72. It has a sandwiched shape, and further has a take-out part 84c at the stepped end of the heating element. .

In the above embodiment, the correspondence between the current of the oxygen pump element and the partial pressure of oxygen in the gas to be measured is the same as in the first embodiment.

In the oxygen sensor of the fourth embodiment described above, the heating element 73 incorporated in the sensor is provided particularly close to the pump element, so that the pump element can be efficiently heated and good temperature compensation and pump element current can be achieved with less electric power. In addition to being able to supply heating elements 73
heating element 73 is insulated and separated from battery element 71 compared to other embodiments.
This makes it possible to further reduce the influence of the battery elements on the battery elements.

In the first to fourth embodiments described above,
The dimensions of each oxygen concentration battery element, oxygen pump element, heating element, insulating plate, intermediate plate, and protective plate are usually set to a length of 5 mm to 70 mm, a width of 3 mm to 10 mm, and a thickness of about 0.5 mm. In addition, the dimensions of the holes provided in them are usually 3 mm to 25 mm in length, 1 mm to 8 mm in width, and depth.
It is set around 0.5mm, and the dimensions of the communication hole are usually the vertical width.
Around 0.5mm, width 0.5mm to 3mm (total cross-sectional area of hole is 1
mm ² or more, more preferably 3 mm ² or more), and the length is set to 1 mm to 3 mm. The width of the peripheral portion of the hole is also set to 1 mm to 3 mm. .

The dimensions of the locking pieces 4 and 5 in the first embodiment are usually length 2 mm to 30 mm, width 3 mm to 14 mm, and thickness 0.5 mm to 1.
Set to mm. Also, similarly protrusions 1c, 2c, 3c
Normally, the width at the base is 5 mm to 30 mm, and the protruding length is 0 mm to 2 mm.
mm, thickness is set around 0.5mm.

The method of integrating these elements, plate-like bodies, etc. into a sensor is to sinter the layers after laminating them in a raw ceramic state, or to use a heat-resistant inorganic adhesive or a heat-resistant inorganic adhesive or This can be done by applying a glass frit paste, laminating them together, stacking them together, and then sintering them.

FIG. 11 shows an example in which the sensor of the first example is assembled as an oxygen sensor probe. Here, the oxygen sensor 101 of the first embodiment has a twelfth
As shown in the figure, the end of the locking part 17 is inserted into the rectangular hole of the disc-shaped stopper 104 and inserted into the metal tubular housing 102.
A filler is filled between the caulked edge 102C of the housing 102 and the housing 102 is fixed. Here, the ceramic adhesive 103 and the dowel 104 are alternately stacked twice, and then the tubular dowel 105 is inserted and fixed in the housing 102 by caulking the inlet edge 102c of the housing 102.

The housing 102 has a shielding tube integrally or separately disposed on its distal end side so as to extend in the axial direction, surrounds the distal end of the oxygen sensor with a gap, and has a hole in the wall for restricting the flow of exhaust gas. Prepare as a physical object. Here, the shielding pipe is a bottomed pipe 102e that is integrally constructed with the housing 102, and the exhaust gas restriction holes are a plurality of closed pipes 102e connected to the side wall and bottom of the pipe.
The case of a and 102b is shown.

Next, the conductive wires 113 connected to each outlet on the sensor source side and the covered wire 112 for connecting to the measured value calculation processing device are connected, and then the covered wire 112 is penetrated at the insertion port 106c for connection. The metal tube 106 is connected to the housing 1 at its mouth 106a.
It is spot welded near the edge 102c of 02.
Next, the insertion port 106c is caulked, the covered electric wire 112 and the connecting metal tube 106 are fixed, and the metal tube 1
A curable synthetic resin or a heat-resistant inorganic adhesive 107 is injected through the hole 106b of 06, and the sensor probe is assembled.

The above sensor probe is used by being screwed into an exhaust manifold or an exhaust gas recirculation pipe of an automobile engine at its threaded portion 102d, for example. In this case, the shielding pipe 102e prevents the tip of the oxygen sensor with a built-in heater from being excessively cooled by the exhaust gas flow, and the gas to be measured at the applicable location flows through the holes 102a and 102b, thereby allowing measurement. .

The oxygen sensor of the present invention has the following characteristics: the oxygen partial pressure of the atmosphere to be measured to which the sensor is exposed; (a quantity directly related to the amount of oxygen molecules transferred through the pump element), and the atmosphere to be measured is defined as the partial pressure of oxygen in the enclosed chamber communicating with the hole and the partial pressure of oxygen in the atmosphere to be measured. This method attempts to measure the oxygen partial pressure in the atmosphere being measured by utilizing the fact that the ratio of Therefore, in addition to the method described in the above example, other methods can be used, for example, under conditions where the pumping current of the oxygen pump element is controlled constant, the oxygen partial pressure in the atmosphere to be measured corresponds to the output voltage of the oxygen concentration battery element. It is also possible to provide a method that takes advantage of the fact that

As detailed above, the oxygen sensor of the present invention is
Two zirconia oxygen ion conductive solid electrolyte plates for an oxygen pump element and an oxygen concentration battery element each having heat-resistant metal layers for electrodes and lead wires on both sides were made with holes in the thickness direction. The intermediate plate-shaped body is sandwiched and laminated into one piece, thereby distinguishing the tip side and the base side, forming a flat enclosed chamber on the tip side and a communication hole that communicates the chamber with the outside world, and forming the chamber. In an oxygen sensor forming an oxygen permeable wall of an oxygen pump element or an oxygen concentration battery element, a voltage is applied or taken out from the source side through lead wires to both walls in the thickness direction, respectively.
By laminating perforated plates or layers of electrically insulating ceramic in at least a portion of the thickness direction, and embedding a heating resistor in or between the plates or layers and around the holes, heat generation is achieved. The current flowing through the resistor does not leak to other elements, and in particular, efficient temperature control is possible without reducing the measurement accuracy of the oxygen concentration battery element.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the first embodiment of the present invention, Fig. 2 is a longitudinal sectional view thereof, Fig. 3 is a perspective view thereof, Fig. 4 is an exploded perspective view of the second embodiment, and Fig. 5 is an exploded perspective view of the first embodiment of the present invention. 6 is a partial view of an insulating plate for explaining the manufacturing method of the second embodiment, FIG. 7 is an exploded perspective view of the third embodiment, and FIG. 8 is a longitudinal sectional view of the insulating plate. An axial sectional view, FIG. 9 is an exploded perspective view of the fourth embodiment, and FIG.
0 is a longitudinal sectional view thereof, FIG. 11 is an assembly diagram of the probe of the oxygen sensor of the first embodiment, and FIG. 12 is an explanatory diagram of the assembly method. 1, 21, 41, 71...Oxygen concentration battery element,
2, 22, 42, 72...oxygen pump element, 3,
23, 43, 73... Heating element, 6... Insulating coat, 26, 46... Insulating plate, 89... Intermediate plate, 1
3, 33, 53, 83...Heating resistor, 9, 1
0, 11, 12, 29, 30, 31, 32, 4
9, 50, 51, 52, 79, 80, 81, 82
...Electrode, 9a, 10a, 11a, 12a, 14
b, 29a, 30a, 31a, 32a, 34b,
49a, 50a, 51a, 52a, 54b, 79
a, 80a, 81a, 82a, 84b... Leading line, 8a, 37a, 37b, 37c, 61a,
61b, 61c, 91a...Communication holes.

Claims (1)

[Claims for Utility Model Registration] 1. Two zirconia oxygen ion conductive solid electrolyte plate bodies for oxygen pump elements and oxygen concentration battery elements, each having heat-resistant metal layers for electrodes and lead wires on both sides. are laminated and integrated by sandwiching an intermediate plate-shaped body having holes in the thickness direction, thereby distinguishing the tip side and the base side, and communicating the flat enclosed chamber on the tip side with the outside world. an oxygen sensor that forms an oxygen permeable wall of an oxygen pump element or an oxygen concentration battery element, in which a voltage is applied or taken out from the source side through lead wires to both walls in the thickness direction of the chamber, respectively. A perforated plate or layer of electrically insulating ceramic is laminated in at least a part of the thickness direction, and a heating resistor is embedded in or between the plates or layers and around the hole. Characteristic oxygen sensor. 2. A utility model in which the intermediate plate-like body is a perforated plate or layer of electrically insulating ceramic in which a heating resistor is embedded, and the intermediate plate-like body forms a communicating hole having a vertical width equal to the thickness in one direction. An oxygen sensor according to registered claim 1. 3. A perforated plate or layer of electrically insulating ceramic in which a heating resistor is embedded is sandwiched and laminated between a plate-like body for an oxygen pump element and a plate-like body for an oxygen concentration battery element; The oxygen sensor according to claim 1, wherein the oxygen sensor is provided around the hole so as to go around the hole. 4 An electrically insulating perforated plate or layer in which a heating resistor is embedded is provided on the outside of the plate-like body for oxygen pump elements and/or the plate-like body for oxygen concentration battery elements, and the thickness of the intermediate plate-like body is 2. The oxygen sensor according to claim 1, wherein one or more communicating holes having a vertical width are formed. 5. The oxygen sensor according to claim 1, wherein the electrically insulating ceramic is alumina or spinel. 6. The oxygen sensor according to claim 1, wherein each of the heat-resistant metal layers of the electrode, its lead wire, and the heating resistor is formed by printing a heat-resistant metal paste and firing it simultaneously with the sintering of each element.