JP2005257334A - Gas sensor element and output adjustment method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an output adjustment method for an inexpensive gas sensor element with a simple element structure capable of absorbing a characteristic individual difference. <P>SOLUTION: The gas sensor element comprises a solid electrolyte 11 and a pair of a reference electrode 4 and a measuring gas-side electrode 3, the pair of electrodes 3 and 4 being electrically connected to a measuring circuit adapted to take out an output. The gas sensor element further comprises a diffusion resistant layer 2 provided so as to cover the surface opposed to a measuring gas of the measuring gas-side electrode 3, the surface of the diffusion resistant layer 2 having a gas inlet part 20 so as to introduce the measuring gas at least from the diffusion resistant layer 2 toward the measuring gas-side electrode 3. When the output of this gas sensor element is adjusted, the area of the measuring gas-side electrode 3 covered with the diffusion resistant layer 2 is adjusted according to an output adjustment quantity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gas sensor element that can be installed in an exhaust system or the like of an internal combustion engine such as an automobile engine and used for combustion control and the like, and an output adjustment method thereof.

In an internal combustion engine such as an automobile engine, a gas sensor provided with a gas sensor element having the following configuration is widely used when air-fuel ratio control is performed.
That is, as shown in FIGS. 11 and 12, the gas sensor element 9 includes a solid electrolyte body 11, a pair of reference electrodes 92 provided on the surface of the solid electrolyte body 11, and a measured gas side electrode 91. The electrodes 91 and 92 are electrically connected to a measurement circuit (not shown) configured to extract output from the pair of electrodes 91 and 92.
A diffusion resistance layer 2 including a dense layer 21 and a porous layer 22 is provided so as to cover a surface of the measurement gas side electrode 91 facing the measurement gas, and at least from the diffusion resistance layer 2 to the measurement target. The surface of the diffusion resistance layer 2 has a gas introduction part 20 so as to introduce a measurement gas toward the gas side electrode 91.

In the gas sensor element 9, the gas concentration is measured as follows.
That is, the gas to be measured enters the diffusion resistance layer 2 through the introduction portion 20 and contacts the gas to be measured side electrode 91.
A measurement circuit is connected between the measured gas side electrode 91 and the reference electrode 92, and a constant voltage is applied between the pair of electrodes 91 and 92 via this measurement circuit.
If the value of the constant voltage is appropriate, the value of the current flowing between the pair of electrodes 91 and 92 is limited by the amount of oxygen molecules passing through the diffusion resistance layer 2.
Therefore, the current value that can be detected in the measurement circuit connected to the pair of electrodes 91 and 92 has a characteristic of being saturated at a specific value if the oxygen concentration in the gas to be measured is constant.

FIG. 13 is a diagram showing the relationship between the voltage applied to the pair of electrodes 91 and 92 and the output current when the oxygen concentration changes from a to d (a>b>c> d).
From the figure, it is understood that an output current corresponding to the oxygen concentration can be obtained by applying an appropriate applied voltage between the pair of electrodes 91 and 92 (V shown in the figure). In the figure, when the oxygen concentration is a, the output current Ia can be obtained.

By the way, when manufacturing a large number of gas sensor elements, individual differences may occur in characteristics due to manufacturing variations.
When a constant voltage V is applied between the pair of electrodes of the gas sensor element exposed to the gas to be measured having an oxygen concentration a, the output current should be Ia.
However, when the output current obtained from a large number of gas sensor elements is actually plotted, a distribution diagram as shown in FIG. 14 is obtained.
Even if a gas sensor element that has obtained an output in the range of ΔIa can be put into practical use as a non-defective product assuming that a certain amount of error is allowed, a gas sensor element having an output corresponding to X exceeding the range of ΔIa has a large measurement error. This is a defective product that cannot be used.

Therefore, in order to improve the manufacturing yield, it is necessary to adjust the output of the defective gas sensor element to a non-defective output range by some means.
Conventionally, it has been proposed to provide an external circuit having a resistor or the like outside the element, adjust the output current by appropriately changing the resistance value of the external circuit, and absorb characteristic individual differences due to manufacturing variations. (See Patent Document 1).
In addition, it has been proposed to process the diffusion resistance layer and change the distance (diffusion distance) until the gas to be measured reaches the electrode from the introduction part to absorb individual differences (see Patent Document 2). .

No. 7-27391 JP 2001-153835 A

However, in the invention according to Patent Document 1, an external circuit, a resistor, and the like separate from the gas sensor element are required for adjusting the output current, and the element configuration may be complicated.
Further, in the invention according to Patent Document 2, since the diffusion resistance characteristics (porosity and pore diameter) of the diffusion resistance layer may vary depending on the location, a target output current can be obtained only by changing the diffusion distance. Was difficult.
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a gas sensor element that can absorb individual characteristic differences, has a low cost, and has a simple element configuration, and an output adjustment method thereof.

The first invention comprises a solid electrolyte body, a pair of reference electrodes provided on the surface of the solid electrolyte body, and a gas side electrode to be measured, and the pair of electrodes is configured to extract output from the pair of electrodes. Electrically connected to the measurement circuit,
And a diffusion resistance layer is provided so as to cover the surface of the measurement gas side electrode facing the measurement gas, and at least the measurement gas is introduced from the diffusion resistance layer toward the measurement gas side electrode. In adjusting the output of the gas sensor element having the gas introduction part, the surface of the diffusion resistance layer is
According to the output adjustment method of the gas sensor element, the area of the measured gas side electrode covered with the diffusion resistance layer is adjusted according to the output adjustment amount.

In the gas sensor element, when an appropriate voltage is applied between the measurement gas side electrode covered with the diffusion resistance layer and the reference electrode, the output current obtained between the two electrodes is the current of the measurement gas passing through the diffusion resistance layer. Limited by quantity.
In general, in a gas sensor element having a measured gas side electrode covered with a diffusion resistance layer, the output current tends to increase as the diffusion cross-sectional area increases.
Therefore, by adjusting the area of the measured gas side electrode covered with the diffusion resistance layer according to the output adjustment amount, the diffusion cross section can be adjusted and the output current can be adjusted. That is, by reducing the area of the measured gas side electrode, the diffusion cross-sectional area can be reduced and the output current can be reduced. On the contrary, by increasing the area of the measured gas side electrode, the diffusion cross-sectional area can be increased and the output current can be increased.

In the gas sensor element according to the first aspect of the invention, the measured gas side electrode is covered with the diffusion resistance layer. Therefore, the gas under measurement reaches the surface of the gas under measurement side electrode from the gas introduction section through the inside of the diffusion resistance layer through the boundary surface between the diffusion resistance layer and the gas side electrode under measurement.
By providing a means for adjusting the area of the measured gas side electrode, the output of the element can be easily adjusted by controlling the diffusion cross-sectional area.
Since the first invention does not use an external circuit using a resistor as described in the prior art as means for adjusting the area of the gas side electrode to be measured, the device configuration is low in cost and simple. Can do.
Furthermore, since the output is adjusted by adjusting the diffusion cross section instead of the diffusion distance, the gas passage time of the diffusion resistance layer due to the difference in the diffusion distance, that is, the response time is less likely to vary between the gas sensor elements. Can be obtained.
As mentioned above, according to 1st invention, the output adjustment method of the gas sensor element which can absorb a characteristic individual difference, is low-cost, and an element structure is simple can be provided.

The second invention comprises a solid electrolyte body, a pair of reference electrodes provided on the surface of the solid electrolyte body, and a measured gas side electrode, and the pair of electrodes is configured to extract output from the pair of electrodes. Electrically connected to the measurement circuit,
The measured gas side electrode is composed of one main electrode and a plurality of adjustment electrodes having a smaller area than the main electrode, and the diffusion distance to the main electrode is L1, and the diffusion distance to the adjustment electrode is L2. The gas sensor element is characterized by satisfying L2 ≦ L1 (Claim 7).

In the gas sensor element according to the second aspect of the invention, the measured gas side electrode includes a main electrode and a plurality of adjustment electrodes having a smaller area than the main electrode.
Therefore, the adjustment electrode can be adjusted according to the magnitude of the output current generated by at least one adjustment electrode by electrically separating the adjustment electrodes one by one from the main electrode (see FIG. 1 described later).
Furthermore, since L2 ≦ L1, it is possible to contribute to the output current of the gas sensor element unless all the adjustment electrodes are electrically disconnected from the main electrode.
If L2> L1, the gas to be measured reaches the main electrode before reaching the adjustment electrode.
For this reason, when the concentration of the specific gas to be detected is low, most of the specific gas is decomposed into oxygen ions at the main electrode, so that it is difficult to reach the adjustment electrode. Therefore, the output current always depends only on the main electrode, and the meaning of providing the adjustment electrode is lost.
Note that L1 and L2 are the shortest distances between the gas introduction part and the ends of the main electrode and the adjustment electrode, and specific dimensions are shown in FIGS.

Since the gas sensor element having the configuration according to the second invention is used, an external circuit using a resistor as described in the prior art is not used as means for adjusting the area of the gas side electrode to be measured. Cost and device configuration can be simplified.
Furthermore, since the output is adjusted by adjusting the diffusion cross section instead of the diffusion distance, the gas passage time of the diffusion resistance layer due to the difference in the diffusion distance, that is, the response time is less likely to vary between the gas sensor elements. Can be obtained.

  As described above, according to the second aspect of the invention, it is possible to provide a gas sensor element output adjustment method that can absorb individual characteristic differences, is low-cost, and has a simple element configuration.

The output adjustment method according to the first aspect of the present invention is an air-fuel ratio sensor element used for combustion control of an internal combustion engine, a limit current type oxygen sensor element, or a gas sensor element for detecting various gas concentrations such as NOx, CO, and HC. Can be applied.
In the gas sensor element according to the second aspect of the invention, the diffusion resistance layer can be configured to cover only the measured gas side electrode, or the entire surface of the solid electrolyte body provided with the measured gas side electrode or It can also be configured to cover the part.
Furthermore, the diffusion resistance layer can be composed of a gas impermeable dense layer and a gas permeable porous layer (see FIG. 2).
Similarly to a general gas sensor element, the solid electrolyte body in the gas sensor element of the second invention can be composed of an oxygen ion conductive ceramic, and the diffusion resistance layer is composed of a porous ceramic. Can do.
Further, the second gas sensor element can have a ceramic heater integrally laminated.

Next, the measurement gas side electrode is composed of one main electrode and a plurality of adjustment electrodes having a smaller area than the main electrode, and the diffusion distance to the main electrode is L1, and the diffusion distance to the adjustment electrode is L2. Then, L2 ≦ L1, and
It is preferable that the adjustment electrode is electrically disconnected or connected from the main electrode in accordance with the output adjustment amount.
Thereby, the adjustment according to the magnitude of the output current generated by the at least one adjustment electrode can be performed (see FIG. 1 described later).

By the way, the mechanism of the specific gas concentration detection in the gas sensor element will be described. When measuring the oxygen concentration, oxygen is ionized on the surface of the gas side electrode to be measured, and the oxygen ions are transferred from the gas side electrode to be measured to the reference electrode. The oxygen concentration is measured by detecting the current at the time of movement as the output current. In the case of NOx or the like, the concentration of NOx or the like is measured by detecting, as an output current, an oxygen ion current due to oxygen ions generated by decomposing NOx or the like on the surface of the gas side electrode to be measured.
As described above, the gas sensor element of the first invention performs measurement using oxygen ions or the like generated by decomposing a specific gas.

If L2> L1, the gas to be measured reaches the main electrode before reaching the adjustment electrode.
For this reason, when the concentration of the specific gas to be detected is low, most of the specific gas is decomposed into oxygen ions at the main electrode, so that it is difficult to reach the adjustment electrode. For this reason, the output current always depends only on the main electrode, and the meaning of providing the adjustment electrode is lost.
Note that L1 and L2 are the shortest distances between the gas introduction part and the ends of the main electrode and the adjustment electrode, and specific dimensions are shown in FIGS.

As a method for electrically disconnecting or connecting the adjustment electrode from the main electrode, for example, there is a method as described below.
That is, an adjustment lead portion that connects the adjustment electrode to the measurement circuit is provided separately, and the adjustment lead portion is disconnected or connected as necessary (see Example 1).
The adjustment lead portion can be provided on the solid electrolyte body (see FIG. 5) or can be provided outside the solid electrolyte body (see Example 2 and FIG. 8).
In addition, a switch structure for turning on / off the electrical continuity of the adjustment lead portion is provided (see Example 2 and FIG. 8), and disconnection and connection are realized by operating this switch. The effect according to the present invention can be obtained with only a simple circuit.
Furthermore, in the configuration provided with the switch, the adjustment lead portion can be reconnected, the adjustment lead portion can be recut, and the range of adjustment and the degree of freedom become wider.

  Further, as a method of cutting the lead portion, there is a method of burning the lead portion using laser irradiation or the like when the lead portion is provided on the solid electrolyte body. Alternatively, there is a method of cutting the lead part together with the solid electrolyte body by using blasting or cutting from the side surface of the gas sensor element or the like (see Example 1).

Next, it is preferable to adjust the output by measuring the output of the gas sensor element and determining an output adjustment amount according to the magnitude of the output (Claim 3) (see Example 1).
Thereby, since it can adjust, measuring an output, output adjustment with higher precision is attained.

Next, it is preferable that the main electrode and the adjustment electrode have different compositions.
By changing the composition, the magnitude of the output current generated by the main electrode and each adjustment electrode can be controlled. Therefore, finer output adjustment can be made possible.
As a specific method for changing the composition, for example, the main electrode and the adjustment electrode both contain Au, but the Au content is different between the main electrode and the adjustment electrode, or only the adjustment electrode contains Au. There is a method of containing (Claim 5).
Alternatively, although both the main electrode and the adjustment electrode contain Rh, there is a method in which the content of Rh is different between the main electrode and the adjustment electrode, or only the adjustment electrode contains Rh (Claim 6).
When the electrode contains Au, the oxygen adsorption force of the electrode is reduced, and the output current is reduced. In addition, since the electrode includes Rh, the oxygen adsorption force of the electrode increases, so that the output current increases. Therefore, by adding Au or Rh and making the content different between the main electrode and the adjustment electrode, the magnitude of the output current generated by the main electrode and the adjustment electrode can be made different.

(Example 1)
The gas sensor element and its output adjustment method according to the present invention will be described.
As shown in FIGS. 1 to 5, the gas sensor element 1 according to this example includes a solid electrolyte body 11, a pair of reference electrodes 4 provided on the surface of the solid electrolyte body 11, and a measured gas side electrode 3. The pair of electrodes 3, 4 are electrically connected to a measurement circuit (not shown) configured to extract output from the pair of electrodes 3, 4, and the measurement gas in the measurement gas side electrode 3 A diffusion resistance layer 2 is provided so as to cover the facing surface, and the surface of the diffusion resistance layer 2 is a gas so that the measurement gas is introduced from at least the diffusion resistance layer 2 toward the measurement gas side electrode 3. It has an introduction part 20.
In adjusting the output of the element 1, the area of the measured gas side electrode 3 covered with the diffusion resistance layer 2 is adjusted according to the output adjustment amount.
Specifically, the measured gas side electrode 3 includes one main electrode 31 and six adjustment electrodes 32a to 32f having a smaller area than the main electrode 31, and has a diffusion distance with respect to the main electrode 31. L1, L2 ≦ L1 where L2 is a diffusion distance with respect to the adjustment electrodes 32a to 32f.
Then, the adjustment electrodes 32 a to 32 f are electrically disconnected from or connected to the main electrode 31 according to the output adjustment amount.

Details will be described below.
As shown in FIGS. 1, 2 and 3, the gas sensor element of this example is provided with a diffusion resistance layer 2, an oxygen ion conductive solid electrolyte body 11, a spacer 12 for forming a reference gas chamber, a heating element 130, and the like. The heater substrate 13 is laminated.
The diffusion resistance layer 2 of this example is formed by laminating a gas impermeable shielding layer 21 on a gas permeable porous layer 22.
Since the gas to be measured cannot enter from the surface covered with the shielding layer 21, the gas introduction part 20 in the gas sensor element 1 according to the configuration of this example has a side surface of the porous layer 22 as shown in FIGS. 2 and 5. 115, 116 and 117 constitute end faces.
On the surface 111 of the solid electrolyte body 11 on the side where the diffusion resistance layer 2 is provided, the measured gas side electrode 3, the terminal portion 391, and the electrode that electrically connects the measured gas side electrode 3 and the terminal portion 391. A lead portion 39 is provided.

The spacer 12 has a groove 120, and a space surrounded by the groove 120 and the surface 112 of the solid electrolyte body 11 serves as a reference gas chamber.
On the surface 112 side of the solid electrolyte body 11, a reference electrode 4 facing the reference gas chamber, an internal terminal portion 490, and an electrode lead portion 49 that electrically connects the reference electrode 4 and the internal terminal portion 490 are provided. . Then, a conductive through hole (not shown) is provided in the internal terminal portion 490 so as to be electrically connected to the terminal portion 491 provided on the surface 111 side.
The terminal portion 391 and the terminal portion 491 are exposed to the outside of the element, and a measurement circuit (not shown) configured to apply a voltage to the electrodes 3 and 4 and take out an output current of the element is connected to the terminal portion 391, 491 is electrically connected.

The measured gas side electrode 3 will be described in detail.
As shown in FIGS. 4 and 5, the measured gas side electrode 3 includes a main electrode 31 and a smaller adjustment electrode 32. The adjustment electrode 32 is connected to the electrode lead portion 39 by the adjustment lead portion 33 and the lead portion 339. Electrically connected.
There are six adjustment electrodes 32 in total, and reference numerals 32a to 32f are given in order from the closest to the main electrode.
The adjustment electrodes 32 a to 32 f are connected to the lead portion 339 by adjustment lead portions 33 a to 33 f, respectively, and the lead portion 339 is further connected to the lead portion 39.
The main electrode is provided on the distal end side of the element in the longitudinal direction, and the adjustment electrode is provided on the proximal end side from the main electrode.
As shown in FIG. 4, the tip side and the base end side of the element were the tip side on the side provided with the gas side electrode to be measured, and the base side was the side provided with the terminal portion.

In this example, each of the adjustment electrodes 32a to 32f has the same composition and the same area.
That is, the main electrode 31 and the adjustment electrodes 32a to 32f are all made of Pt.
In the gas sensor element of this example, the gas to be measured is introduced from the side surface of the porous layer 22 in the diffusion resistance layer 2 as indicated by the arrow h in FIG. The diffusion distance is as shown in FIG. 5 and L2 = L1.

A method for adjusting the output of the gas sensor element 1 of this example will be described in detail.
In the gas sensor element 1 of this example, the output adjustment is realized by electrically disconnecting the adjustment electrodes 32 a to 32 f from the lead portion 39.
Further, in this output adjustment, while measuring the output of the gas sensor element, the output adjustment amount is determined according to the magnitude of the output to adjust the output.
That is, as shown in FIG. 5, the adjustment lead part 33 for connecting the adjustment electrodes 32a to 32f of this example to the lead part 39 is composed of six parts 33a to 33f, 33a being the outermost element and 33f being the innermost part. Located in. 33a is electrically connected to the adjustment electrode 32a, and 33f is electrically connected to the adjustment electrode 32f.
Then, along the broken line 330 shown in FIG. 5, the diffusion resistor layer and the solid electrolyte body are cut into the element using a cutter.

As a result, as shown in FIG. 6, the output current in a state where the adjustment lead portion 33 is not cut is the sum of the output currents obtained from the main electrode 31 and the six adjustment electrodes 32, and obtained from the main electrode. Assuming that the output current is A (mA) and the output current obtained from one adjustment electrode 32 is B (mA), A + 6B. (In addition, since all the adjustment electrodes 32 have the same area, the same output current B is obtained.)
If the cut is made here and the adjustment lead portion 33a located on the outermost side is cut, the output current decreases by B, and becomes A + 5B.
By making the cut larger and larger, each adjustment lead portion 33 is cut, and the output current decreases by B each time one is cut, and finally the output current becomes A.

Therefore, according to this example, a gas sensor element having an output current distribution as shown in FIG. 7 is manufactured, and the range of output current allowed for this gas sensor element is Ia0 to Ia1.
In this case, the gas sensor element corresponding to the range (range n) of the portion X shown in the figure has a large output current and cannot be used without being adjusted. Other sensor elements falling in the range m can be used without adjustment.

Therefore, the gas sensor element 1 is connected to an ammeter for measuring an output current and a measurement circuit having a power source for applying a voltage to the pair of electrodes 3 and 4.
First, a voltage is applied, and the output current in a state where all the adjustment lead portions 33 are not cut is measured.
When the measured value is larger than Ia1, using the cutter as described above, the element 1 is cut along with the diffusion resistance layer 2 and the solid electrolyte body 11, and one adjustment lead portion 33a to 33f is cut. did.
The voltage is applied again to measure the output current. When the output current becomes smaller than Ia1, the processing is interrupted and the element 1 is separated as a non-defective product.
When the output current is larger than Ia1, the adjustment lead portions 33 are cut one by one until the output current becomes smaller than Ia1, so that the range of the output current becomes Ia0 to Ia1.
Thereby, all defective products in the range n are within the range m and can be used as good products.

The effect of this example will be described.
In the gas sensor element 1 according to this example, the measured gas side electrode 3 is covered with the diffusion resistance layer 2. Therefore, the gas to be measured reaches the surface of the gas side electrode 3 to be measured from the gas introduction part 20 through the inside of the diffusion resistance layer 2 through the boundary surface between the diffusion resistance layer 2 and the gas side electrode 3 to be measured. To do.
In this example, as a means for adjusting the area of the gas side electrode 3 to be measured, an external circuit and a resistor as described in the prior art are not used, and the gas side electrode 3 to be measured is composed of the main electrode 31 and six adjustment electrodes. 32, and the adjustment lead portion 33 that conducts between the adjustment electrode 32 and the lead portion 39 by cutting the element 1 together with the diffusion resistance layer 2 and the solid electrolyte body 11 is cut.
Thereby, a low-cost element and a simple element can be obtained.
Furthermore, in this example, because the output is adjusted by a method of adjusting the diffusion cross section instead of the diffusion distance,
The effect that can be obtained.
As described above, according to this example, it is possible to provide a gas sensor element and an output adjustment method that can absorb individual characteristic differences, are low in cost, and have a simple element configuration.

  Note that the output adjustment can be performed by irradiating the laser through the diffusion resistance layer to burn out the adjustment lead portion.

(Example 2)
As shown in FIG. 8, the gas sensor element 1 of this example includes a measured gas side electrode 3 including a main electrode 31 and an adjustment electrode 32 similar to those of the first embodiment.
However, the end of the adjustment lead portion 33 is drawn out of the element 1, provided with an adjustment lead portion 339 so as to be electrically connected to the lead portion 39 for the main electrode 31, and drawn out of the element 1 by the adjustment lead 33. A switch 331 is provided for the part.
Note that the lead portion 39 of the main electrode 31 is also drawn out of the device from the middle.

The output adjustment of the gas sensor element 1 is performed as follows.
That is, when all the switches 331 are turned on, the output current of the element 1 is the sum of the output currents obtained from the main electrode 31 and the six adjustment electrodes 32, and the output current obtained from the main electrode is A (mA). When the output current obtained from one adjustment electrode 32 is B (mA), A + 6B. (In addition, since all the adjustment electrodes 32 have the same area, the same output current B is obtained.)
Here, one of the switches 331 is turned off. The output current decreases by B and becomes A + 5B.
By increasing the number of switches 331 to be turned off, the output current decreases by B, and finally the output current becomes A.
This is used to adjust the output current.
The other detailed configuration is the same as that of the first embodiment, and has the same effects as those of the first embodiment.

(Example 3)
In this example, a gas sensor element 1 having a measured gas side electrode 3 including a main electrode 31 and an adjustment electrode 32 arranged as shown in FIG. 9 will be described.
In the gas sensor element 1 of this example, the lead part 339, the six adjustment electrodes 33, and the main electrode 31 were arranged in this order from the front end side in the longitudinal direction of the element.
The diffusion resistance layer is composed of a porous layer and a shielding layer so that the gas to be measured is introduced only from the side surface 116 of the element (not shown).
The diffusion distance L1 with respect to the main electrode 31 and the diffusion distance L2 with respect to the adjustment electrode are as shown in FIG. 9, and L2 ≦ L1.
The other detailed configuration is the same as that of the first embodiment and has the same effects as the first embodiment.

Example 4
As shown in FIG. 10, this example is a gas sensor element 1 having a measured gas side electrode 3 composed of a main electrode 31 and an adjustment electrode 32 in the same arrangement as in the first embodiment.
However, unlike Example 1, the gas to be measured is introduced from the side surfaces 115 and 117 of the element 1, and the diffusion resistance layer is composed of a porous layer and a shielding layer so that the gas to be measured does not enter from 116 (illustrated). Abbreviation).
The other detailed configuration is the same as that of the first embodiment and has the same effects as the first embodiment.

FIG. 3 is an explanatory diagram of a gas sensor element according to the first embodiment. Sectional explanatory drawing of the gas sensor element concerning Example 1. FIG. 1 is a perspective development view of a gas sensor element according to Embodiment 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main part explanatory diagram of a solid electrolyte body and a measured gas side electrode according to Example 1; FIG. 3 is a diagram illustrating a relationship between an output current and the number of cuts of an adjustment lead portion according to the first embodiment. FIG. 3 is a diagram illustrating a relationship between an output current and the number of gas sensor elements according to the first embodiment. Explanatory drawing of the solid electrolyte body concerning to Example 2, and a to-be-measured gas side electrode. FIG. 6 is an explanatory diagram of a main part of a solid electrolyte body and a measured gas side electrode according to Example 3; Explanatory drawing of the principal part of the solid electrolyte body concerning to Example 4, and a to-be-measured gas side electrode. The top view of the gas sensor element concerning a prior art. Cross-sectional explanatory drawing of the gas sensor element concerning a prior art. The diagram which shows the relationship between an output current and an applied voltage in a gas sensor element. The diagram which shows the relationship between an output electric current and the number of gas sensor elements.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas sensor element 11 Solid electrolyte body 2 Diffusion resistance layer 3 Gas to be measured side electrode 31 Main electrode 32 Adjustment electrode 4 Reference electrode

Claims (7)

It consists of a solid electrolyte body, a pair of reference electrodes provided on the surface of the solid electrolyte body, and a gas side electrode to be measured, and the pair of electrodes is electrically connected to a measurement circuit configured to extract output from the pair of electrodes. Connected,
And a diffusion resistance layer is provided so as to cover the surface of the measurement gas side electrode facing the measurement gas, and at least the measurement gas is introduced from the diffusion resistance layer toward the measurement gas side electrode. In adjusting the output of the gas sensor element having the gas introduction part, the surface of the diffusion resistance layer is
A method for adjusting an output of a gas sensor element, comprising adjusting an area of a gas-side electrode to be measured covered by a diffusion resistance layer according to an output adjustment amount. 2. The measured gas side electrode according to claim 1, comprising one main electrode and a plurality of adjustment electrodes having a smaller area than the main electrode, and the diffusion distance to the main electrode is L1, and the diffusion distance to the adjustment electrode Is L2, L2 ≦ L1,
A gas sensor element output adjustment method, wherein the adjustment electrode is electrically disconnected from or connected to the main electrode according to an output adjustment amount.   3. The gas sensor element output adjustment method according to claim 1, wherein the output is adjusted by measuring an output of the gas sensor element and determining an output adjustment amount according to a magnitude of the output.   4. The gas sensor element output adjustment method according to claim 2, wherein the main electrode and the adjustment electrode have different compositions.   5. The output adjustment method for a gas sensor element according to claim 4, wherein both the main electrode and the adjustment electrode contain Au, but the contents thereof are different or only the adjustment electrode contains Au.   5. The gas sensor element output adjustment method according to claim 4, wherein both the main electrode and the adjustment electrode contain Rh, but their contents are different, or only the adjustment electrode contains Rh. It consists of a solid electrolyte body, a pair of reference electrodes provided on the surface of the solid electrolyte body, and a gas side electrode to be measured. The pair of electrodes is electrically connected to a measurement circuit configured to extract output from the pair of electrodes. Connected,
The measured gas side electrode is composed of one main electrode and a plurality of adjustment electrodes having a smaller area than the main electrode, and the diffusion distance to the main electrode is L1, and the diffusion distance to the adjustment electrode is L2. A gas sensor element, wherein L2 ≦ L1.

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