JP2016217849A - Particulate matter detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particulate matter detection sensor 1 with which it is possible to stably collect particulate matter and improve detection accuracy.SOLUTION: A particulate matter detection sensor 1 includes an element body part 10. A first accumulation part 21 and a second accumulation part 22 are formed as an accumulation part 2 in the element body part 10. At least one pair of first detection electrodes 31 are disposed in the first accumulation part 21, and at least one pair of second detection electrodes 32 are disposed in the second accumulation part 22. The particulate matter detection sensor 1 is configured so that the output of an electric signal is changed in accordance with a change in electrical characteristics between one pair of first detection electrodes 31 and between one pair of second detection electrodes 32 due to the accumulation of particulate matter in the first accumulation part 21 and the second accumulation part 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a particulate matter detection sensor.

  An exhaust gas purification apparatus that collects particulate matter (PM) contained in the exhaust gas is provided in an exhaust pipe of the internal combustion engine. This exhaust gas purification device includes a particulate matter detection device having a particulate matter detection sensor that detects the amount of particulate matter contained in the exhaust gas, and based on information obtained by this particulate matter detection device, Failure detection of the exhaust gas purification device is performed.

  As a particulate matter detection sensor used in an exhaust gas purification apparatus, for example, there is one disclosed in Patent Document 1. The particulate matter detection sensor of Patent Document 1 has a substrate having electrical insulation and a detection electrode formed on the surface of the substrate. The amount of the particulate matter is detected by utilizing the fact that the electrical resistance between the detection electrodes is changed by depositing the particulate matter on the substrate.

JP 59-197847 A

However, the particulate matter detection sensor of Patent Document 1 has the following problems.
In the particulate matter detection sensor of Patent Document 1, the collection performance varies greatly depending on the relationship between the direction in which the surface of the substrate on which the detection electrode is formed faces and the flow direction of the exhaust gas flowing through the exhaust pipe. That is, when exhaust gas flows toward the surface on which the detection electrode of the substrate is formed, the collection efficiency is high, and the collection efficiency decreases as the surface of the substrate on which the detection electrode is formed faces the opposite side. In addition, the particulate matter detection sensor generally includes a protective cover for preventing damage to the substrate and the detection electrode, and exhaust gas flows through an introduction hole formed in the protective cover. Since the flow of the exhaust gas flowing through the protective cover changes with changes in the flow rate and flow rate of the exhaust gas, it is not constant and varies. Therefore, the detection sensitivity of the particulate matter detection sensor is likely to vary.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a particulate matter detection sensor that can stably collect particulate matter and improve detection sensitivity.

One aspect of the present invention includes an element body for detecting the amount of particulate matter contained in exhaust gas discharged from an internal combustion engine,
The element main body portion is formed with at least a first deposition portion and a second deposition portion facing opposite sides as a deposition portion for depositing a part of the particulate matter,
The first deposition portion is provided with at least a pair of first detection electrodes,
At least a pair of second detection electrodes are disposed in the second deposition portion,
An electrical signal corresponding to a change in electrical characteristics between the pair of first detection electrodes and between the pair of second detection electrodes due to the particulate matter being deposited on the first deposition portion and the second deposition portion. The particulate matter detection sensor is configured to change the output of the particulate matter.

  In the particulate matter detection sensor, the element main body portion includes at least the first deposition portion and the second deposition portion disposed as facing the opposite sides as the deposition portion. Yes. As described above, by forming the plurality of deposited portions, it is possible to increase the collection amount of the particulate matter in the particulate matter detection sensor. In addition, by collecting the particulate matter in a plurality of the deposited portions, it is possible to reduce the influence of the flow direction of the exhaust gas when collecting the particulate matter. That is, even if one of the first depositing portion and the second depositing portion is arranged to face the downstream side in the exhaust gas flow direction, the other is located upstream in the exhaust gas flow direction. It is arranged to face. Thereby, in the said particulate matter detection sensor, the said particulate matter can be collected stably and the detection sensitivity can be improved.

  As described above, according to the present invention, it is possible to provide a particulate matter detection sensor that can stably collect particulate matter and improve detection sensitivity.

FIG. 3 is an explanatory diagram showing an element main body in Example 1. II-II arrow sectional drawing in FIG. III-III arrow sectional drawing in FIG. FIG. 3 is an explanatory diagram showing a structure of an element main body in Example 1. FIG. 3 is an explanatory diagram illustrating a particulate matter detection sensor according to the first embodiment. The graph which shows the test result in the comparative test 1. FIG. FIG. 6 is an explanatory diagram showing an element main body in Example 2. VIII-VIII arrow sectional drawing in FIG. FIG. 6 is an explanatory diagram showing an element body in Example 3. FIG. 6 is an explanatory diagram showing an element body in Example 4. FIG. 10 is an explanatory view showing an element main body in Example 5. FIG. 10 is an explanatory diagram illustrating a structure of an element main body in Example 5. FIG. 10 is an explanatory view showing an element body in Example 6. Explanatory drawing which shows the structure of the element main-body part in Example 6. FIG.

  In the particulate matter detection sensor, it is preferable that the portion to be deposited is formed on the entire outer peripheral side surface parallel to the axial direction of the element body portion. In this case, the particulate matter can be collected on the entire circumference of the outer peripheral side surface of the particulate matter detection sensor. Therefore, the influence by the distribution direction of exhaust gas can be reduced and the collection efficiency can be improved.

  Further, the element main body has a pair of flat surfaces parallel to the axial direction and parallel to each other, and the first deposition portion and the second deposition portion are respectively provided on the pair of flat surfaces. And the arrangement direction of the first detection electrodes in the first deposition portion and the arrangement direction of the second detection electrodes in the second deposition portion are the same arrangement direction, and a plurality of the first detection electrodes are arranged. Among the plurality of second detection electrodes and the plurality of second detection electrodes, a potential difference is generated between the first detection electrode and the second detection electrode arranged at the same end in the arrangement direction. Preferably it is. In this case, an electric field is formed between the first detection electrode and the second detection electrode arranged at the end in the arrangement direction. By using this electric field, the particulate matter can be collected. Thereby, the collection performance in the particulate matter detection sensor can be further improved.

  Further, the thickness t of the element main body portion in the arrangement direction of the first deposition portion and the second deposition portion, and the lateral direction orthogonal to both the axial direction and the arrangement direction of the element main body portion. It is preferable that the width w of the element body satisfies the relationship t / w ≦ 0.6. In this case, an electric field is more likely to be generated between the first deposition portion and the second deposition portion. Thereby, the said particulate matter which exists in the said horizontal direction of the said particulate matter detection sensor can be collected more efficiently, and the collection performance can be improved.

  In addition, the element main body has a columnar shape, and it is preferable that the deposited portion is formed on the outer peripheral side surface parallel to the axial direction. In this case, the exhaust gas can easily flow around the portion to be deposited, and the exhaust gas and the element main body can be efficiently contacted. Thereby, the collection efficiency of the particulate matter detection sensor can be improved.

Example 1
An embodiment according to the particulate matter detection sensor will be described with reference to FIGS.
As shown in FIGS. 1 and 5, the particulate matter detection sensor 1 includes an element body 10 that detects the amount of particulate matter contained in the exhaust gas discharged from the internal combustion engine. The element body 10 is formed with at least a first depositing portion 21 and a second depositing portion 22 that face opposite sides as the depositing portion 2 for depositing a part of the particulate matter. At least a pair of first detection electrodes 31 is disposed on the first deposition portion 21, and at least a pair of second detection electrodes 32 is disposed on the second deposition portion 22. In the present embodiment, the first deposition target portion 21 is one surface of the element main body portion 10. The second deposition portion 22 is a surface different from the first deposition portion 21 in the element body 10. In the present embodiment, the second deposition portion 22 is the opposite surface to the first deposition portion 21. That is, the first depositing portion 21 and the second depositing portion 22 face opposite to each other.
The particulate matter detection sensor 1 has electrical characteristics between the pair of first detection electrodes 31 and between the pair of second detection electrodes 32 due to the particulate matter being deposited on the first deposition portion 21 and the second deposition portion 22. The output of the electric signal is changed in accordance with the change of the signal.

This will be described in more detail below.
As shown in FIG. 5, the particulate matter detection sensor 1 of this example is for detecting particulate matter contained in exhaust gas discharged through an exhaust pipe from an internal combustion engine mounted on an automobile. Based on the information obtained by the particulate matter detection sensor 1, failure detection of the exhaust gas purification device is performed. The particulate matter detection sensor 1 is disposed so as to protrude inside the exhaust pipe.
The particulate matter detection sensor 1 includes an element body 10, a protective cover 7, and a housing member (not shown) that holds them.

As shown in FIGS. 2 and 4, the element body 10 includes a first detection layer 41 in which the first deposition portion 21 is formed, a second detection layer 42 in which the second deposition portion 22 is formed, The intermediate layer 43 disposed between the first detection layer 41 and the second detection layer 42 is laminated.
The first detection layer 41 includes a first substrate 411 having electrical insulation and a first detection electrode 31 formed on the first substrate 411. The first substrate 411 is formed by forming a ceramic material into a flat plate shape. In this example, alumina is used as the ceramic material constituting the first substrate 411, but zirconia, magnesia, beryllia, or the like can also be used. In the first substrate 411, a pair of first through holes 412 are formed penetratingly at positions on the back surface side of the connection end portion 344 of the first detection electrode 31.

  The pair of first detection electrodes 31 formed on the surface of the first substrate 411 is formed in a flat film shape by screen printing. In the element body 10, the surface on which the pair of first detection electrodes 31 is formed on the first substrate 411 is the first deposition target portion 21 for depositing the particulate matter.

  The pair of first detection electrodes 31 includes a positive electrode and a negative electrode. The electrode base 341 is formed in parallel with the longitudinal direction of the first deposition target portion 21, and extends from the electrode base 341 perpendicular to the longitudinal direction. Each has a bent portion 342 and a plurality of comb teeth portions 343 extending from the bent portion 342. In the electrode base 341, a connection end 344 having an enlarged width is formed at the end opposite to the side where the bent portion 342 is formed. The electrode base portion 341 and the bent portion 342 in the positive electrode and the negative electrode are disposed so as to face each other, and the comb tooth portions 343 in the negative electrode are disposed between the comb tooth portions 343 in the positive electrode.

  The second detection layer 42 includes a second substrate 421 having electrical insulation and a second detection electrode 32 formed on the second substrate 421. The second substrate 421 and the second detection electrode 32 are formed in the same shape as the first substrate 411 and the first detection electrode 31. That is, the second detection layer 42 has the same shape as the first detection layer 41. The first detection layer 41 and the second detection layer 42 are disposed with the intermediate layer 43 interposed therebetween so that the first deposited portion 21 and the second deposited portion 22 face opposite sides.

  As shown in FIGS. 1 to 3, the element body 10 has a pair of flat surfaces 12 that are parallel to the axial direction X and parallel to each other, and the first deposition target portions are respectively provided on the pair of flat surfaces 12. 21 and a second deposition portion 22. The arrangement direction of the first detection electrodes 31 in the first deposition portion 21 and the arrangement direction of the second detection electrodes 32 in the second deposition portion 22 are the same arrangement direction. In this example, the arrangement direction coincides with the lateral direction Y orthogonal to both the axial direction X and the arrangement direction Z of the element main body 10.

  In this example, the electrical resistance between the plurality of comb teeth 343 is detected, and the direction in which the plurality of comb teeth 343 are arranged is the arrangement direction. As shown in FIG. 3, one of the first detection electrode 31 and the second detection electrode 32 arranged at the end on the same side in the arrangement direction (lateral direction Y) is a positive electrode 31p, 32p (high potential), and the other is It arrange | positions so that it may become the negative electrodes 32n and 31n (low potential). That is, a potential difference is generated between the first detection electrode 31 and the second detection electrode 32 arranged at the end on the same side in the arrangement direction, and an electric field is formed between the two.

  The intermediate layer 43 includes an intermediate structure 431 having electrical insulation and a component 433 built in the intermediate structure 431. The intermediate structure 431 is made of a ceramic material and has a block shape in which a part 433 is included. In this example, alumina is used as the ceramic material constituting the first substrate 411, but zirconia, magnesia, beryllia, or the like can also be used. In addition, the intermediate structure 431 is formed with a pair of intermediate through holes 432 that are formed so as to penetrate in the alignment direction Z of the first deposition portion 21 and the second deposition portion 22. The intermediate through-hole 432 is formed at a position inside the lateral direction Y from the first through-hole 412 and the second through-hole 422 when viewed from the arrangement direction Z and at a position avoiding the component 433. In this example, the component 433 incorporated in the intermediate layer 43 is a heater for heating the first deposition target portion 21 and the second deposition target portion 22.

  As shown in FIG. 2, the first detection electrode 31 and the second detection electrode 32 are electrically connected by the lead member 6. The lead member 6 includes a first lead 61 having one end electrically connected to the first detection electrode 31, a second lead 62 having one end electrically connected to the second detection electrode 32, and a first lead. An intermediate lead portion 63 that electrically connects the other end of the portion 61 and the other end of the second lead portion 62 is provided.

The first lead portion 61 is electrically connected to the connection end portion 344 of each of the pair of first detection electrodes 31, and is inserted into the first through hole 412.
The second lead portions 62 are electrically connected to the connection end portions 344 of the pair of second detection electrodes 32, respectively, and are inserted into the second through holes 422.

  The intermediate lead part 63 includes a first connection part 631 connected to the first lead part 61, a second connection part 632 connected to the second lead part 62, a first connection part 631, and a second connection part 632. And an intermediate connection portion 633 for connecting the two. The first connection portion 631 is disposed between the first detection layer 41 and the intermediate layer 43 so as to go from the first through hole 412 to the intermediate through hole 432. The second connection portion 632 is disposed between the second detection layer 42 and the intermediate layer 43 so as to go from the second through hole 422 to the intermediate through hole 432. The intermediate connection portion 633 is inserted and disposed in the intermediate through hole 432 and electrically connects the first connection portion 631 and the second connection portion 632.

  As described above, the element main body 10 is configured by laminating the first detection layer 41, the intermediate layer 43, and the second detection layer 42. The thickness t of the element body 10 in the arrangement direction Z of the first deposition portion 21 and the second deposition portion 22 and the lateral direction Y orthogonal to both the axial direction X and the arrangement direction Z of the element body 10. The width w of the element body 10 preferably satisfies the relationship t / w ≦ 0.6. Moreover, it is preferable that t / w ≧ 0.2 from the viewpoint of ensuring the strength of the element body 10 against external force such as vibration. In this example, t / w = 0.4.

  When a collection voltage is applied to the detection electrodes (the first detection electrode 31 and the second detection electrode 32) in the deposition portion 2 of the particulate matter detection sensor 1, an electric field is formed around the detection electrodes, and the particulate matter is It is attracted to the detection electrode. Particulate matter adhering to the detection electrode moves on the surface of the detection electrode and is deposited between the pair of detection electrodes. Then, the particulate matter deposited on the portion to be deposited 2 conducts the pair of detection electrodes exposed to the portion to be deposited 2, and the electrical resistance value between the pair of detection electrodes decreases. As the electrical resistance value between the detection electrodes changes, the amount of current as an electrical signal flowing between the detection electrodes changes. Thereby, the current value output from the particulate matter detection sensor 1 changes. That is, the current value output from the particulate matter detection sensor 1 changes according to the amount of particulate matter deposited in the deposition target portion 2 and has information on the amount of particulate matter deposited. By using this current value, it is possible to detect the amount of particulate matter deposited in the portion 2 to be deposited. In this example, the current detected by the particle amount detection means is output to a control unit having a shunt resistance, and the control unit outputs a voltage calculated by the product of the current value and the shunt resistance. This voltage becomes the output of the particulate matter detection sensor 1.

As shown in FIG. 5, the protective cover 7 includes an inner cover 71 and an outer cover 72 disposed on the outer peripheral side of the inner cover 71.
The inner cover 71 has a cylindrical inner wall portion 711 that surrounds the element body 10 and an inner bottom portion 712 formed at the tip of the inner wall portion 711. The inner cover 71 is caulked and fixed to the tip of a housing member (not shown).

A plurality of inner introduction holes 713 are formed in the inner wall portion 711. The inner introduction hole 713 has a circular shape. When viewed from the axial direction X, the plurality of inner introduction holes 713 are formed at equal intervals in the circumferential direction of the inner wall portion 711. Further, the inner introduction hole 713 is formed at a position facing the first deposition portion 21 and the second deposition portion 22 of the element body 10.
An inner discharge hole 714 that penetrates in the axial direction X is formed at the center of the inner bottom portion 712.

  The outer cover 72 has a cylindrical outer wall portion 721 that surrounds the inner cover 71 from the outer periphery, and an outer bottom portion 722 formed at the tip of the outer wall portion 721. The outer cover 72 is caulked and fixed together with the inner cover 71 to the distal end portion of a housing member (not shown).

A plurality of outer introduction holes 723 are formed in the outer side wall portion 721. The outer introduction hole 723 has a circular shape. When viewed from the axial direction X, the plurality of outer introduction holes 723 are formed at equal intervals in the circumferential direction of the outer wall portion 721, and each outer introduction hole 723 and each inner introduction hole 713 has a circumferential shape. It is formed at the same position in the direction. The outer introduction hole 723 is formed at a position closer to the tip than the inner introduction hole 713.
An outer discharge hole 724 penetratingly formed in the axial direction X is formed at the center of the outer bottom portion 722.
In the particulate matter detection sensor 1 of this example, the exhaust gas G introduced from the plurality of outer introduction holes 723 is configured to be introduced from the inner introduction hole 713 to the inner side of the inner cover 71.

Next, the function and effect of this example will be described.
In the particulate matter detection sensor 1, the element main body 10 includes at least a first deposition target portion 21 and a second deposition target portion 22 that are disposed to face opposite sides as the deposition target portion 2. Yes. In this way, by forming the plurality of deposited portions 2, the amount of collected particulate matter in the particulate matter detection sensor 1 can be increased. In addition, by collecting the particulate matter in the plurality of deposited portions 2, it is possible to reduce the influence of the flow direction of the exhaust gas when collecting the particulate matter. That is, even if one of the first depositing part 21 and the second depositing part 22 is arranged in the same direction as the exhaust gas flow direction, the other is arranged facing the exhaust gas flow direction. Thereby, in the particulate matter detection sensor 1, particulate matter can be collected stably, and its detection sensitivity can be improved.

  The element main body 10 has a pair of flat surfaces 12 that are parallel to the axial direction X and parallel to each other, and the first deposition target portion 21 and the second deposition target portion are respectively formed on the pair of flat surfaces 12. 22. The arrangement direction of the first detection electrodes 31 in the first deposition portion 21 and the arrangement direction of the second detection electrodes 32 in the second deposition portion 22 are the same arrangement direction, and the plurality of first detection electrodes 31 and Among the plurality of second detection electrodes 32, a potential difference is generated between the first detection electrode 31 and the second detection electrode 32 arranged at the end on the same side in the arrangement direction. Therefore, an electric field is formed between the first detection electrode 31 and the second detection electrode 32 disposed at the end in the arrangement direction. By using this electric field, particulate matter can be collected. Thereby, the collection performance in the particulate matter detection sensor 1 can be further improved.

  Further, the thickness t and the width w of the element body 10 satisfy the relationship of t / w ≦ 0.6. Therefore, an electric field is more likely to be generated between the first deposition portion 21 and the second deposition portion 22. Thereby, the particulate matter existing in the lateral direction Y of the particulate matter detection sensor can be collected more efficiently, and the collection performance can be improved.

  The element body 10 includes a first detection layer 41 in which a first deposition portion 21 is formed on a first substrate 411 having electrical insulation, and a second substrate 421 having electrical insulation. 2 The component 433 is placed inside the second detection layer 42 in which the deposited portion 22 is formed, and the intermediate structure 431 provided between the first detection layer 41 and the second detection layer 42 and having electrical insulation. And a built-in intermediate layer 43. The first substrate 411 is formed with a first through hole 412 formed through in the alignment direction Z of the first deposition portion 21 and the second deposition portion 22, and the second substrate 421 has an alignment direction. A second through hole 422 penetratingly formed in Z is formed. The first detection electrode 31 and the second detection electrode 32 are electrically connected by the lead member 6. The lead member 6 has one end electrically connected to the first detection electrode 31 and inserted into the first through hole 412, and one end electrically connected to the second detection electrode 32. The second lead portion 62 inserted through the two through holes 422 and the intermediate lead portion 63 that electrically connects the other end of the first lead portion 61 and the other end of the second lead portion 62 are provided. . The corners of the element body 10 are likely to come into contact with each other during transportation or the like, and if the lead member 6 is disposed here, there is a risk of disconnection and special management may be required. The lead member 6 has a portion disposed inside the element body 10 by being inserted through the first through hole 412 and the second through hole 422. Therefore, the first detection electrode 31 and the second detection electrode 32 can be electrically connected by the lead member 6 without being exposed at the corner of the element body 10.

  The first detection electrode 31 and the second detection electrode 32 are formed in a flat film shape on the surface of the deposition target portion 2. Therefore, the first detection electrode 31 and the second detection electrode 32 can be easily formed by screen printing or the like.

  As described above, according to this example, it is possible to provide the particulate matter detection sensor 1 that can stably collect particulate matter and improve the detection sensitivity.

(Comparative test 1)
In this comparative test 1, the detection sensitivity when the ratio (t / w) of the thickness t to the width w in the element body 10 was changed was compared.
In Comparative Test 1, six particulate matter detection sensors of Comparative Example 1 and Specimen 1 to Specimen 5 were used.
The particulate matter detection sensor of Comparative Example 1 has only the first deposition target portion 21 as the deposition target portion 2. That is, the particulate matter detection sensor of Comparative Example 1 is obtained by eliminating the second deposition portion in the particulate matter detection sensor of Example 1.

Like the particulate matter detection sensor 1 of Example 1, each of the specimen 1 to specimen 5 has a first depositing portion 21 and a second depositing portion 22 as the depositing portion 2, and has a thickness. The ratio t / w between the length t and the width w is different. The ratio t / w in each particulate matter detection sensor 1 is 1.0 for the specimen 1, 0.8 for the specimen 2, 0.6 for the specimen 3, 0.4 for the specimen 4, and 0.4 for the specimen 5. 0.2.
In Comparative Example 1 and Specimen 1 to Specimen 5, the structures other than those described above are the same as in Example 1.

The test conditions in Comparative Test 1 were the insensitive mass when an exhaust gas having a temperature in the vicinity of the particulate matter of 200 ° C. and a particulate matter concentration of 3 mg / m ³ was circulated at a flow rate of 20 m / s. As shown in FIG. 1, the flow direction of the exhaust gas is such that the direction facing the first deposition portion 21 in the arrangement direction Z is the direction A, the direction parallel to the lateral direction Y (arrangement direction) is the direction B, and the opposite direction to the direction A. The direction was designated as direction C. Note that the dead mass indicates the total amount of particulate matter discharged until the output signal changes in the particulate matter detection sensor 1. The results of Comparative Test 1 are shown in Table 1.

  As shown in Table 1, the dead mass in Comparative Example 1 is 80 mg when the flow direction of the exhaust gas is the direction A, 95 mg when the direction of the exhaust gas is B, and 111 mg when the direction of the exhaust gas is the direction C. It was confirmed that the detection sensitivity was lowered as the direction of the position deviated from the state of facing the flow direction of the exhaust gas.

  Moreover, in the specimen 1 to the specimen 5, the dead mass in the direction A and the direction C was almost the same. Also, the difference between the dead mass in the direction A and the direction C and the dead mass between the direction B and the average value of the dead mass in the directions A to C are smaller than those in the comparative example. Moreover, it was confirmed that the difference of the dead mass in the direction A to the direction C and the average value of the dead mass became smaller as t / w became smaller. The graph shown in FIG. 6 is a graph with the average value of dead mass as the vertical axis and the ratio t / w as the horizontal axis. In the figure, it can be seen that the slope of the graph is large when the ratio t / w is between 0.6 and 0.8, and the amount of decrease in dead mass is large. Therefore, it was confirmed that the detection sensitivity was particularly improved when the ratio t / w was 0.6 or less.

(Example 2)
In this example, as shown in FIGS. 7 and 8, the structure of the particulate matter detection sensor 1 of Example 1 is partially changed.
The particulate matter detection sensor 1 of the present example has a third deposition target portion 23 formed on the tip surface of the element body portion 10. A pair of third detection electrodes 33 is formed on the third deposition portion 23. The third detection electrode 33 is composed of a positive electrode and a negative electrode. The third detection electrode 33 is opposed to each other and formed in a pair of electrode bases 331 along the lateral direction Y (arrangement direction), and from each electrode base 331 to the opposing electrode base 331. And a plurality of comb teeth portions 332 extending toward the surface. The electrode base portion 331 and the bent portion 342 in the positive electrode and the negative electrode are disposed so as to face each other, and the comb tooth portions 332 in the negative electrode are disposed between the comb tooth portions 332 in the positive electrode.

The pair of third detection electrodes 33 is connected to the lead member 6 by connection electrode portions 333 formed on a pair of side end surfaces 113 arranged in the lateral direction Y in the element main body portion 10.
In the intermediate lead portion 63 of the lead member 6 of this example, the first connection portion 631 is disposed between the first detection layer 41 and the intermediate layer 43 from the first through hole 412 toward the side end face 113. Yes. The second connection portion 632 is disposed between the second detection layer 42 and the intermediate layer 43 from the second through hole 422 toward the side end face 113. The intermediate connection portion 633 is exposed at the side end surface 113 and electrically connects the first connection portion 631 and the second connection portion 632.
Other configurations are the same as those of the first embodiment. Of the reference numerals used in this example or the drawings relating to this example, the same reference numerals as those used in the first embodiment represent the same components as in the first embodiment unless otherwise specified.
In addition, the same effects as those of the third embodiment can be obtained.

Example 3
This example is an example of the particulate matter detection sensor 1 including a pair of detection electrodes 3 as shown in FIG.
In the particulate matter detection sensor 1 of the present example, the element main body 10 includes a base material portion 101 made of an insulating material and an outer peripheral surface 11 formed in parallel with the axial direction X of the base material portion 101. And a deposition part 2. A pair of detection electrodes 3 is formed on the portion to be deposited 2, and the pair of detection electrodes 3 includes an electrode base 331 formed on the surface 111 that is one of the outer peripheral side surfaces 11 and a plurality of comb teeth portions. 301 and 302. The electrode base portion 331 is arranged in parallel with each other in the axial direction X, and a plurality of comb-tooth portions 301 and 302 are extended from the electrode base portion 331.

  The plurality of comb-tooth portions 301 and 302 are extended from each electrode base portion 331 toward the opposite electrode base portion 331 and toward the opposite side of the first comb-tooth portion 301. The second comb tooth portion 302 is provided. The second comb tooth portion 302 reaches the front surface 111 via the back surface 112 opposite to the end surface on which the electrode base portion 331 is disposed and the pair of side end surfaces 113 connecting the front surface 111 and the back surface 112. In other words, the first comb tooth portion 301 and the second comb tooth portion 302 are formed on the entire circumference of the outer peripheral side surface 11 parallel to the axial direction X of the element main body portion 10, and the deposited portion is formed on the entire circumference of the outer peripheral side surface 11. 2 is formed. In the present example, the pair of detection electrodes 3 serves as both the first detection electrode 31 and the second detection electrode 32 in the first embodiment. A part of the deposition target portion 2 formed over the entire circumference of the outer peripheral side surface 11 is a first deposition target portion 21 and a second deposition target portion 22. Further, the particulate matter detection sensor 1 of this example does not include the lead member 6 in the first embodiment.

  Other configurations are the same as those of the first embodiment. Of the reference numerals used in this example or the drawings relating to this example, the same reference numerals as those used in the first embodiment represent the same components as in the first embodiment unless otherwise specified.

As described above, in the particulate matter detection sensor 1 of this example, the portion to be deposited 2 is formed on the entire circumference of the outer peripheral side surface 11 parallel to the axial direction X of the element body 10. Thereby, the particulate matter can be collected on the entire circumference of the outer peripheral side surface 11 of the particulate matter detection sensor 1. Therefore, the influence by the distribution direction of exhaust gas can be reduced and the collection efficiency can be improved.
In addition, the same effects as those of the first embodiment can be obtained.

Example 4
In this example, as shown in FIG. 10, the structure of the particulate matter detection sensor 1 in Example 3 is partially changed.
In the particulate matter detection sensor 1 of the present example, the element main body 10 is a portion to be deposited on the entire circumference of the outer peripheral side surface 11 disposed in parallel with the axial direction X in the columnar base member 102 made of an insulating material. 2 is formed. A pair of detection electrodes 3 is formed on the deposition portion 2, and the pair of detection electrodes 3 includes an electrode base portion 331 formed on the outer peripheral side surface 11 in parallel with the axial direction X, and a plurality of first comb teeth portions. 301 and a plurality of second comb teeth 302. Also in this example, a part of the deposition target portion 2 formed over the entire circumference of the outer peripheral side surface 11 is a first deposition target portion 21 and a second deposition target portion 22.

In this example, it can be considered that the first deposition part 21 and the second deposition part 22 exist in the vicinity of the left and right contour lines in FIG. In this case, a plurality of second comb tooth portions 302 are mainly formed in the first accumulation portion 21 and the second accumulation portion 22. In FIG. 10, the reference numerals (21, 22, Z) are given based on such a grasping method. However, it can also be considered that the first depositing portion 21 and the second depositing portion 22 exist in portions corresponding to the front and back of the paper surface in FIG. In this case, a plurality of first comb teeth portions 301 are formed at the center of the first accumulation portion 21 and the second accumulation portion 22.
Other configurations are the same as those of the third embodiment. Of the reference numerals used in this example or the drawings relating to this example, the same reference numerals as those used in the third embodiment denote the same components as in the third embodiment unless otherwise specified.

In the particulate matter detection sensor 1 of this example, the element main body 10 has a cylindrical shape, and the portion to be deposited 2 is formed on the outer peripheral side surface 11 parallel to the axial direction X. Therefore, the exhaust gas easily flows around the portion 2 to be deposited, and the exhaust gas and the element body 10 can be efficiently contacted. Thereby, the collection efficiency of the particulate matter detection sensor 1 can be improved.
Also in this example, the same effects as those of the first embodiment can be obtained.

(Example 5)
This example is an embodiment of the particulate matter detection sensor 1 formed by a laminated structure as shown in FIGS.
In the particulate matter detection sensor 1 of the present example, the element main body 10 has a laminated portion 5 in which four electrode layers 51 and a plurality of insulating members 52 having electrical insulation properties are alternately laminated. As a result, the end face of the electrode layer 51 is exposed at the end face 5, thereby forming the first deposition part 21 and the second deposition part 22 having the first detection electrode 31 and the second detection electrode 32 on the end face of the stacked part 5. Has been.

The electrode layer 51 is formed on one surface of the insulating member 52 before firing by screen printing using a copper paste, a silver paste, or the like. In this example, the electrode layer 51 is formed over the entire length between a pair of end faces that are orthogonal to the longitudinal direction of the insulating member 52 and are arranged in the alignment direction Z when stacked. By laminating the insulating member 52 on which the electrode layer 51 is formed and then firing, the laminated portion 5 in which the insulating member 52 and the electrode layer 51 are alternately laminated is formed.
Other configurations are the same as those of the first embodiment. Of the reference numerals used in this example or the drawings relating to this example, the same reference numerals as those used in the first embodiment represent the same components as in the first embodiment unless otherwise specified.

The element main body 10 in the particulate matter detection sensor 1 of the present example has a laminated portion 5 in which a plurality of electrode layers 51 and a plurality of insulating members 52 having electrical insulation properties are alternately laminated. When the end face of the electrode layer 51 is exposed at the end face 5, the first deposition part 21 having the first detection electrode 31 and the second deposition part 22 having the second detection electrode 32 are provided on the end face of the stacked part 5. Is formed. In the laminated structure forming the laminated part 5, the distance between the detection electrodes 3 can be easily reduced. Thereby, the detection sensitivity in the particulate matter detection sensor 1 can be further improved.
Also in this example, the same effects as those of the first embodiment can be obtained.

(Comparative test 2)
In Comparative Test 2, the detection sensitivity of the particulate matter detection sensor having a laminated structure was compared.
In Comparative Test 2, two particulate matter detection sensors of Comparative Example 2 and Specimen 6 were used.
The particulate matter detection sensor of Comparative Example 2 has only the first deposition portion 21 as the deposition portion 2 as in the conventionally used particulate matter detection sensor. That is, the particulate matter detection sensor of Comparative Example 2 is obtained by deleting the configuration of the second deposited portion 22 in the particulate matter detection sensor 1 (FIG. 11) of Example 5. Other configurations are the same as those of the fifth embodiment.
The specimen 6 is the particulate matter detection sensor 1 of Example 5.

The test condition in Comparative Test 2 was that the insensitive mass was measured when an exhaust gas having a temperature near the particulate matter of 200 ° C. and a particulate matter concentration of 3 mg / m ³ was circulated at a flow rate of 20 m / s. As shown in FIG. 11, the flow direction of the exhaust gas is the direction A facing the first deposition portion 21 in the arrangement direction Z, the direction B parallel to the lateral direction Y (arrangement direction), and the opposite direction to the direction A. The direction was designated as direction C.

  Table 2 shows the results of Comparative Test 2. As shown in Table 2, the dead mass in the comparative example is 28 mg when the flow direction of the exhaust gas is the direction A, 32 mg when the direction of the exhaust gas is B, and 39 mg when the direction of the exhaust gas is the direction C. It was confirmed that the detection sensitivity decreased as the direction deviated from the upstream direction of the exhaust gas.

  Moreover, in the specimen 6, the dead mass in the direction A and the direction C was the same. In addition, the difference between the dead mass in the direction A and the direction C and the dead mass between the direction B and the average value of the dead mass in the directions A to C are smaller than those in the comparative example 2. In the specimen 6, it was confirmed that the detection sensitivity was improved as compared with Comparative Example 2.

(Example 6)
This example is a modification of the particulate matter detection sensor 1 according to the fifth embodiment as shown in FIGS. 13 and 14.
In the particulate matter detection sensor 1 of this example, the element body 10 has a cylindrical shape formed by alternately laminating electrode layers 51 and insulating members 52 formed in a disk shape. The end surface of the electrode layer 51 is disposed over the entire circumference of the outer peripheral side surface 11 disposed in parallel with the axial direction X of the element main body 10, and the detection electrode 3 is formed on the entire circumference of the outer peripheral side surface 11. Yes. Therefore, the portion to be deposited 2 is formed on the entire circumference of the outer peripheral side surface 11, and a part of the portion to be deposited 2 is a first portion to be deposited 21 and a second portion to be deposited 22.

The detection electrode 3 is formed with a positive electrode 3p and a negative electrode 3n arranged side by side in the axial direction X of the element main body 10, and the positive electrodes 3p and the negative electrodes 3n are arranged inside the element main body 10, respectively. The lead members 6 are electrically connected.
Other configurations are the same as those of the fifth embodiment. Of the reference numerals used in this example or the drawings relating to this example, the same reference numerals as those used in the fifth embodiment denote the same components as in the fifth embodiment unless otherwise specified.
In this example, it is possible to obtain a combined effect of the operational effect of the fourth embodiment and the operational effect of the fifth embodiment.

DESCRIPTION OF SYMBOLS 1 Particulate matter detection sensor 10 Element main-body part 2 Deposited part 21 1st deposited part 22 2nd deposited part 31 1st detection electrode 32 2nd detection electrode

Claims (8)

An element body (10) for detecting the amount of particulate matter contained in the exhaust gas discharged from the internal combustion engine;
In the element main body (10), as a portion to be deposited (2) on which a part of the particulate matter is deposited, the first portion to be deposited (21) and the second portion to be deposited ( 22) is formed at least,
At least a pair of first detection electrodes (31) is disposed in the first deposition portion (21),
At least a pair of second detection electrodes (32) is disposed in the second deposition portion (22),
The particulate matter is deposited on the first deposition part (21) and the second deposition part (22), and between the pair of first detection electrodes (31) and the pair of second detection electrodes (32). The particulate matter detection sensor (1) is configured to change the output of an electrical signal in accordance with a change in electrical characteristics between the two).   The element body (10) has a pair of flat surfaces (12) parallel to the axial direction (X) and parallel to each other, and the first deposition target is formed on the pair of flat surfaces (12), respectively. And an arrangement direction of the first detection electrodes (31) in the first deposition portion (21), and the second deposition portion (22). The arrangement direction of the second detection electrodes (32) is the same arrangement direction, and among the plurality of first detection electrodes (31) and the plurality of second detection electrodes (32), the arrangement direction is the same. 2. The device according to claim 1, wherein a potential difference is generated between the first detection electrode (31) and the second detection electrode (32) arranged at the end on the same side. Particulate matter detection sensor (1).   The thickness t of the element body (10) in the alignment direction (Z) of the first deposition part (21) and the second deposition part (22), and the axial direction of the element body (10) The width w of the element body (10) in the lateral direction (Y) orthogonal to both (X) and the arrangement direction (Z) satisfies the relationship of t / w ≦ 0.6. The particulate matter detection sensor (1) according to claim 1 or 2.   2. The particle according to claim 1, wherein the portion to be deposited (2) is formed on the entire circumference of the outer peripheral side surface (11) parallel to the axial direction (X) of the element body (10). A substance detection sensor (1).   The element body (10) has a cylindrical shape, and the deposition portion (2) is formed on an outer peripheral side surface (11) parallel to the axial direction (X). Or the particulate matter detection sensor (1) of 4. The element body (10) has a first detection layer (41) in which the first deposition portion (21) is formed on a first substrate (411) having electrical insulation, and electrical insulation. A second detection layer (42) having the second deposited portion (22) formed on the second substrate (421), and the first detection layer (41) and the second detection layer (42). An intermediate layer (43) in which a component (433) is built inside an intermediate structure (431) disposed between and having electrical insulation;
The first substrate (411) is formed with a first through hole (412) formed through in the alignment direction (Z) of the first deposition portion (21) and the second deposition portion (22). Has been
The second substrate (421) is formed with a second through hole (422) formed so as to penetrate in the arrangement direction (Z).
The first detection electrode (31) and the second detection electrode (32) are electrically connected by a lead member (6), and one end of the lead member (6) is the first detection electrode ( 31) and a first lead portion (61) that is electrically connected to the first through hole (412) and one end thereof is electrically connected to the second detection electrode (32) and the second through hole. A second lead portion (62) inserted through the hole (422), an intermediate lead for electrically connecting the other end of the first lead portion (61) and the other end of the second lead portion (62). It has a part (63), The particulate matter detection sensor (1) as described in any one of Claims 1-5 characterized by the above-mentioned.   It has a laminated part (5) in which a plurality of electrode layers (51) and a plurality of insulating members (52) having electrical insulation properties are alternately laminated, and the electrode layer (5) is formed on the end face of the laminated part (5). When the end face of 51) is exposed, the first deposition part (21) and the second detection electrode (32) provided with the first detection electrode (31) are provided on the end face of the stacked part (5). The particulate matter detection sensor (1) according to any one of claims 1 to 6, wherein the second deposition part (22) provided is formed.   The first detection electrode (31) and the second detection electrode (32) are formed in a flat film shape on the surface of the deposition part (2), respectively. Particulate matter detection sensor (1).

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