JP6678084B2 - Particulate matter detection sensor and particulate matter detection device - Google Patents

Description

  The present invention relates to a particulate matter detection sensor for detecting particulate matter contained in a gas to be measured, and a particulate matter detection device using the same.

  2. Description of the Related Art There is known an electric resistance type particulate matter detection sensor that detects particulate matter (that is, Particulate Matter; hereinafter, appropriately referred to as PM) in exhaust gas discharged from an internal combustion engine. An electric resistance type particulate matter detection sensor generally includes a sensor element provided with a PM detection unit on the surface of an insulating substrate, and a resistance value change caused by deposition of conductive particulate matter between a pair of detection electrodes. Is detected. The particulate matter detection sensor is disposed, for example, downstream of a diesel particulate filter (hereinafter, referred to as DPF) in an exhaust gas passage, and is used for failure diagnosis of the DPF. The failure determination is made based on, for example, whether the output of the sensor element has exceeded a preset threshold.

  On the other hand, with the recent tightening of exhaust gas regulations, it is required to detect PM emissions more quickly. At this time, since the output of the sensor element has temperature dependency, it has been studied to provide a temperature detection unit in the sensor element unit and perform output correction in accordance with the sensor element temperature. As an example, Patent Literature 1 includes a sensor element having a pair of detection electrodes opposed to each other on a substrate, a temperature detection resistor provided in a conduction path that conducts between the pair of detection electrodes, and a capacitor arranged in series. A particulate matter detection sensor is disclosed. The sensor element switches between a first state in which power is not supplied to a series circuit including a temperature detection resistor and a capacitor, and a second state in which power is supplied to the series circuit. Then, in a first state in which a DC signal is applied between the pair of detection electrodes, the particulate matter is detected, and in a second state in which an AC signal is applied, the sensor element temperature is detected.

JP 2011-247650 A

  In Patent Document 1, the sensor element is configured such that a substrate on which a temperature detection resistor is formed is sandwiched between a substrate on which a pair of detection electrodes are formed and a substrate on which a heater electrode is formed. In that case, the temperature detection resistor is disposed inside the sensor element, is adjacent to the PM detection unit via the substrate, and detects the average temperature of the sensor element. In such a configuration, the particulate matter detection sensor cannot directly measure the surface temperature of the PM detection unit on which the particulate matter accumulates, so that the responsiveness and followability to the temperature change of the exhaust gas become insufficient. . As a result, there is a limit in improving the accuracy of PM detection, and development of a more responsive particulate matter detection sensor is desired.

  The present invention has been made in view of such a background, and it is possible to quickly and accurately detect the temperature of a detection unit of a sensor element on which particulate matter is deposited, and improve the detection accuracy of the particulate matter by the detection unit. And a particulate matter detection device using the same.

One embodiment of the present invention provides
A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3) ,
As for the pair of metal wires, at least in a portion where the sensor element is exposed to the gas to be measured (G), a portion excluding the pair of ends is buried inside the sensor element. In the sensor.
Another aspect of the present invention provides
A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3),
The sensor element has an insulating substrate (11) formed of a laminate of a plurality of insulating sheets (12), and the sensor element is formed on a surface of the insulating substrate formed of a stacked surface of the plurality of insulating sheets. Part is formed,
Between the two insulating sheets adjacent to each other, the metal films (310, 320) constituting the pair of metal wires are buried, and the edge of the metal film exposed to the portion to be deposited is In the particulate matter detection sensor constituting the pair of ends.
Another aspect of the present invention provides
A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3),
The sensor element has an insulating base (11) formed of a laminate of a plurality of insulating sheets (12a, 12b), and a sheet of the insulating sheet (12a) serving as a surface of the insulating base (11). A metal film (310, 320) constituting the pair of metal wires is disposed on a surface, and a part of the metal film disposed on the deposition target portion provided on the sheet surface is a part of the pair of metal wires. In the particulate matter detection sensor constituting the end portion.
Another aspect of the present invention provides
A particulate matter detection sensor (S) including a sensor element (1) disposed in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires arranged on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3) ,
The detection section has a pair of detection electrodes (21, 22) arranged apart from each other in the portion to be deposited, and one (31) of the pair of metal wires is connected to the pair of detection electrodes. And one of the pair of detection electrodes is a ground electrode, and is formed of a metal material having the same composition as one of the pair of metal wires. In the substance detection sensor.

Another embodiment of the present invention includes the particulate matter detection sensor described above, and a sensor control unit (5),
The sensor element includes the portion to be deposited on the tip side in the longitudinal direction (X),
Ends of the pair of metal wires opposite to the contact point are connected to a pair of temperature measurement terminals (30) provided on a base end side of the sensor element.
The particulate matter detection device, wherein the sensor control unit includes a temperature detection unit (52) connected to the pair of temperature measurement terminals and detecting an electromotive force between the pair of temperature measurement terminals. It is in.

  In the particulate matter detection sensor, the pair of metal wires of the temperature measuring unit constitute a thermocouple, and detects the temperature of the portion to be deposited. That is, by detecting a thermoelectromotive force generated between dissimilar metals due to a temperature difference between the contact point where the pair of ends is joined and the other end serving as a reference, the temperature of the portion to be deposited is further increased. The temperature of the detecting unit that detects the particulate matter can be directly detected. This makes it possible to detect a change in temperature of the portion to be deposited with good responsiveness and good followability. For example, the accuracy of detecting particulate matter can be improved by temperature correction based on the detection result of the temperature measurement unit.

  Such a particulate matter detection sensor can constitute a particulate matter detection device together with a sensor control unit provided outside the measured gas passage. The particulate matter detection sensor, for example, arranges the tip side of the sensor element including the portion to be deposited in the gas passage to be measured, and arranges the base end side outside the gas passage to be measured, and detects by the sensor control unit. Controls the detection of particulate matter in the section. At this time, the temperature detection unit of the sensor control unit detects the temperature of the portion to be deposited quickly from the thermoelectromotive force generated at the pair of temperature measurement terminals on the base end side, and reflects the detection result to the sensor control. Can be.

As described above, according to the above aspect, it is possible to realize a particulate matter detection sensor that quickly and accurately detects the temperature of the detection unit of the sensor element and improves the particulate matter detection accuracy. Further, it is possible to provide a particulate matter detection device that can accurately perform, for example, a failure diagnosis in an exhaust system of an internal combustion engine using the particulate matter detection sensor.
Note that reference numerals in parentheses described in the claims and means for solving the problems indicate the correspondence with specific means described in the embodiments described below, and limit the technical scope of the present invention. Not something.

FIG. 2 is an enlarged view of a main part of a sensor element included in the particulate matter detection sensor according to the first embodiment. FIG. 1 is an overall perspective view of a sensor element according to a first embodiment. FIG. 2 is an exploded perspective view of the sensor element according to the first embodiment. 1 is a schematic configuration diagram of an exhaust system of an internal combustion engine provided with a particulate matter detection device including a particulate matter detection sensor according to a first embodiment. 1 is an overall schematic configuration diagram of a particulate matter detection device according to a first embodiment. FIG. 4 is a flowchart of a failure diagnosis process executed by an ECU including a sensor control unit according to the first embodiment. FIG. 4 is a diagram illustrating a change over time of a temperature detected by a temperature measurement unit with respect to a change in exhaust gas temperature in the first embodiment, as compared with a conventional example. FIG. 4 is a diagram illustrating a change over time of a sensor output by a detection unit with respect to a change in exhaust gas temperature in Embodiment 1 in a case where temperature correction is performed and a case where temperature correction is not performed. FIG. 10 is an enlarged view of a main part of a sensor element included in the particulate matter detection sensor according to the second embodiment. FIG. 10 is a front view of a main part of a sensor element according to the second embodiment. FIG. 10 is an exploded perspective view of a sensor element according to the second embodiment. FIG. 10 is an enlarged view of a main part of a sensor element constituting a particulate matter detection sensor according to a third embodiment. FIG. 10 is an overall perspective view of a sensor element according to a third embodiment. FIG. 13 is an exploded perspective view of a sensor element according to the fourth embodiment. The principal part enlarged view which shows the structure of the sensor element of the particulate matter detection sensor in Embodiment 4. FIG. 13 is an exploded perspective view illustrating a configuration of a sensor element according to a fourth embodiment. The principal part enlarged view which shows the structure of the sensor element of the particulate matter detection sensor in Embodiment 5. FIG. 13 is an overall perspective view showing a configuration of a sensor element according to a fifth embodiment. FIG. 15 is an exploded perspective view illustrating a configuration of a sensor element according to a fifth embodiment. FIG. 13 is an overall schematic diagram illustrating a configuration of a particulate matter detection device according to a fifth embodiment. FIG. 13 is an enlarged view of a main part of a sensor element constituting a particulate matter detection sensor according to a sixth embodiment. FIG. 17 is an exploded perspective view of a sensor element according to the sixth embodiment. FIG. 17 is an enlarged view of a main part of a sensor element constituting a particulate matter detection sensor according to a seventh embodiment.

(Embodiment 1)
Hereinafter, embodiments of a particulate matter detection sensor and a particulate matter detection device will be described with reference to the drawings. As shown in FIG. 4, an example of application to an exhaust system of an internal combustion engine is shown. A particulate matter detection sensor S is attached to an exhaust gas passage E1 of an internal combustion engine E as a gas passage to be measured, and an exhaust gas G as a gas to be measured. Detect particulate matter contained in the water. The particulate matter detection sensor S includes a sensor element 1 whose front end side (that is, the lower side in the figure) is disposed in the exhaust gas passage E1 and is exposed to the exhaust gas G. The sensor element 1 includes terminals 20 to 40 on the base end side (that is, the upper side in the drawing) disposed outside the exhaust gas passage E1, and the sensor control unit 5 outside the exhaust gas passage E1 via the terminals 20 to 40. To form a particulate matter detection device.

  As shown in FIGS. 1 to 3, the sensor element 1 is configured as, for example, a rectangular parallelepiped laminated sensor. Here, the left-right direction in the figure is the longitudinal direction X of the sensor element 1, and the up-down direction in the figure is the stacking direction Y of the sensor element 1. The sensor element 1 includes a portion to be deposited 10 on which particulate matter contained in the exhaust gas G is deposited on a surface exposed to the exhaust gas G, and an electric resistance type detection portion 2 for detecting the particulate matter deposited on the portion to be deposited 10. And The detection unit 2 detects a change in electrical characteristics due to deposition of conductive particulate matter. The sensor element 1 includes an insulating base 11 made of a laminated body, and a portion 10 to be deposited is provided on a surface formed by laminating a plurality of insulating sheets 12.

In addition, the sensor element 1 includes a temperature measuring unit 3 having a pair of metal wires 31 and 32 made of dissimilar metals, and a contact 33 to which tips 31a and 32a, which are a pair of ends, are joined. The tips 31a, 32a and the contact 33 are arranged on the portion to be deposited 10, and the end opposite to the contact 33 is located outside the exhaust gas passage E1. The temperature measuring unit 3 detects the temperature of the portion 10 on which the contacts 33 are disposed, based on the thermoelectromotive force generated by the temperature difference between the contact 33 on the distal end side and the end on the opposite side from the base end side. Further, a heater section 4 is embedded in the sensor element 1.
Details of the structure of these components will be described later.

  As schematically shown in FIG. 4, exhaust gas G is discharged from the internal combustion engine E to the exhaust gas passage E1. The internal combustion engine is, for example, a diesel engine, and the exhaust gas G contains minute particulate matter having conductivity such as soot generated by combustion. In the middle of the exhaust gas passage E1, a diesel particulate filter (hereinafter, referred to as DPF) 6 for trapping particulate matter is arranged to constitute an exhaust gas purification device. The DPF 6 having a known structure can be used. For example, the DPF 6 is formed of a ceramic filter in which a large number of passages surrounded by porous partition walls are arranged in parallel. The particulate matter detection sensor S is disposed downstream of the DPF 6, and detects particulate matter that passes through the DPF 6 and leaks downstream. The particulate matter detection device including the particulate matter detection sensor S is used for failure diagnosis of the exhaust gas purification device.

  In the particulate matter detection sensor S, a housing H that holds the outer periphery of the sensor element 1 is attached to the wall of the exhaust gas passage E1. A half of the sensor element 1 on the distal end side from the housing H projects into the exhaust gas passage E1. The front half of the sensor element 1 is covered with a cover S1 fixed to the housing H. The cover S1 is usually provided with a plurality of gas flow holes. The longitudinal direction X of the sensor element 1 (for example, the vertical direction in the figure) is orthogonal to the flow direction of the exhaust gas G (for example, the horizontal direction in the figure). At this time, the exhaust gas G is taken into the inside from the gas circulation holes provided in the cover body S <b> 1 and reaches the sensor element 1.

  An electronic control unit (hereinafter, referred to as an ECU) 7 including a sensor control unit 5 is provided outside the exhaust gas passage E1 to control the operation of the internal combustion engine E. The sensor control section 5 includes an output detection section 51 connected to the pair of terminal sections 20 of the detection section 2 and a pair of temperature measurement terminal sections (hereinafter abbreviated as a pair of terminal sections) 30 of the temperature measurement section 3. It has a temperature detecting section 52 connected thereto and a heater control section 53 connected to the pair of terminal sections 40 of the heater section 4. The temperature measuring section 3 is connected to a temperature detecting section 52 through a pair of terminal sections 30 and a pair of compensating lead wires 50 made of the same material as the metal wires 31 and 32.

  1 and 2, the sensor element 1 has a rectangular parallelepiped-shaped insulative base 11, and has a tip (ie, a front side surface on one side) extending in the longitudinal direction X (ie, a front side surface in the drawing). , The right end of the figure) is the portion 10 to be deposited. The sensor element 1 is attached, for example, in the exhaust gas passage E1 so that the portion to be deposited 10 faces the upstream side of the flow of the exhaust gas G, and collects the particulate matter of the exhaust gas G. A pair of detection electrodes 21 and 22 constituting the detection unit 2 are arranged on the portion to be deposited 10 to detect particulate matter deposited on the portion to be deposited 10. The pair of detection electrodes 21 and 22 have polarities different from each other, and each of the detection electrodes 21 and 22 has a plurality of linear electrodes 21a and 22a having the same polarity. The linear electrodes 21a and 22a exposed on the surface of the portion to be deposited 10 have the same shape with a predetermined line width and line length. For example, three linear electrodes 21a and 22a are respectively arranged.

  In the portion to be deposited 10, the plurality of linear electrodes 21a and 22a are alternately arranged in parallel at equal intervals, and a plurality of pairs of electrodes are formed by the adjacent linear electrodes 21a and the linear electrodes 22a. I have. The size and arrangement of the linear electrodes 21a and 22a and the interval between the electrode pairs are appropriately set according to the size and required characteristics of the particulate matter to be detected, and the interval can be changed for each electrode pair. The plurality of linear electrodes 21a and 22a are connected to each other inside the insulating base 11 to form the detection electrodes 21 and 22, respectively, and are provided at the base end (that is, the left end in the drawing) of the insulating base 11. The terminal 20 is connected to the first terminal 20a and the second terminal 20b. Here, the first terminal 20a and the second terminal 20b are provided on a surface adjacent to the side surface on which the deposition target portion 10 is provided in the stacking direction Y (that is, the upper surface in the drawing).

  The sensor element 1 is provided with a pair of tips 31 a and 32 a of metal wires 31 and 32 constituting the temperature measuring section 3 and a contact point 33 thereof, adjacent to the detecting section 2. The portions of the metal wires 31 and 32 of the temperature measuring unit 3 other than the tip portions 31a and 32a are embedded in the sensor element 1. The pair of tip portions 31a, 32a and the contact point 33 are arranged side by side on the upper surface side of the detection electrodes 21, 22 on the surface of the portion 10 to be deposited. Specifically, the tip 31a of the metal wire 31 made of a different metal and the tip 32a of the metal wire 32 are arranged in a straight line, and the adjacent edges are joined to form the linear electrode 21a. , 22a are formed. The contact point 33 is located at the midpoint of this continuous line. The ends of the metal wires 31 and 32 opposite to the contacts 33 extend to the base side inside the insulating base 11, respectively, and the first terminals of the terminal parts 30 provided on the upper surface of the base end of the insulating base 11. 30a and the second terminal 30b.

  In the stacking direction Y, a heater unit 4 is provided on a side opposite to the temperature measuring unit 3 across the detection unit 2 (that is, on a lower surface side in the drawing). The heater unit 4 has a heater electrode 41 buried inside the insulating base 11 at a position adjacent to the detection electrodes 21 and 22, and heats the detection unit 2 to a predetermined temperature.

  As shown in FIG. 3, the insulating base 11 is formed of a laminate of a plurality of flat insulating sheets 12. The insulating sheet 12 is made of, for example, an insulating ceramic material such as alumina. In the stacking direction Y, the first terminal 20a and the second terminal 20b of the detecting unit 2 and the first terminal 20a of the temperature measuring unit 3 are arranged on the surface of the uppermost insulating sheet 12 along the base edge in the longitudinal direction X. The first terminal 30a and the second terminal 30b are provided side by side. On the surface of the lower insulating sheet 12, metal films 310 and 320 to be the metal wires 31 and 32 of the temperature measuring unit 3 are arranged so as to have a predetermined width and a predetermined shape. The terminal portions 20 and 30 and the metal films 310 and 320 are formed by, for example, known screen printing.

  The metal films 310 and 320 are embedded between the uppermost insulating sheet 12 and the lower insulating sheet 12, and a part thereof forms a pair of tip portions 31 a and 32 a. The to-be-deposited part 10 is formed on the surface of the insulating base 11 formed of the laminated surface of the insulating sheet 12. Specifically, the metal films 310 and 320 include linear exposed portions 311 and 321 arranged along one side edge of the insulating sheet 12 and subsequent inverted L-shaped embedded portions 312 and 322, respectively. Consists of In the exposed portions 311 and 321, the edge portions linearly exposed to the deposition target portion 10 become a pair of tip portions 31 a and 32 a of the metal wires 31 and 32. The buried portions 312 and 322 extend inward from the opposite sides of the contact portions 33 of the exposed portions 311 and 321, bend in an inverted L shape, and extend to the base end side in the longitudinal direction X.

  As a result, the portions of the metal wires 31 and 32 except for the pair of tip portions 31a and 32a are embedded in the insulating base 11, and the ends of the metal wires 31 and 32 opposite to the contacts 33 are connected to the insulating base 11 Through the interior to the proximal end. The pair of base ends of the metal wires 31 and 32 are connected to the first terminal 30a and the second terminal 30b located directly above the metal wires 31 and 32 via through holes TH1 and TH2 provided in the insulating sheet 12, respectively. One of the metal wires 31 and 32 has a + leg, and the other has a-leg, according to the combination of dissimilar metals. Here, as shown in FIG. 5, for example, the metal wire 31 is connected to the first terminal 30a as a leg, and the metal wire 32 is connected to the second terminal 30b as a negative leg.

  Below the temperature measuring section 3, a plurality of insulating sheets 12 on which a plurality of linear electrodes 21a and 22a of the detecting section 2 are formed are arranged. Specifically, the insulating sheet 12 formed on the surface so that the electrode film 210 serving as the linear electrode 21a has a predetermined shape, and the electrode film 220 serving as the linear electrode 22a have a predetermined shape. The insulating sheets 12 formed on the surface as described above are alternately laminated to form a pair of detection electrodes 21 and 22. The electrode films 210 and 220 are formed by, for example, known screen printing. The electrode film 210 and the electrode film 220 are formed in an L-shape or an inverted L-shape, and one side disposed along the side edge on the front end side of the insulating sheet 12 has a linear shape. To form a linear electrode 21a and a linear electrode 22a. The other side of the L-shaped or inverted L-shaped electrode film 210 and the electrode film 220 are connected to each other via a through hole TH3 or a through hole TH4 provided in the adjacent insulating sheet 12.

  In the detecting section 2, the insulating sheet 12 on which the uppermost electrode film 210 or electrode film 220 is formed has lead portions 21b and 22b extending from the electrode film 210 or electrode film 220 to the base end side. The lead portions 21b and 22b are connected to each other via a through hole TH5 or a through hole TH6 provided in the adjacent insulating sheet 12, and respectively connected to the first terminal 20a and the second terminal 20b of the terminal portion 20 in the uppermost layer. Connected. The through holes TH1 to TH6 are filled with a conductive material.

  An insulating sheet 12 on which the heater electrode 41 of the heater unit 4 is formed is disposed below the detection unit 2. Lead portions 42 and 43 extending from both end portions of the heater electrode 41 to the base end side are formed on the insulating sheet 12. The lead portions 42 and 43 are provided on the base end side of the insulating sheet 12 with the first terminal 40a and the second terminal 40b of the terminal portion 40 provided on the lower surface thereof through the through hole TH7 or the through hole TH8, respectively. Connected.

  Here, the linear electrodes 21a and 21b constituting the pair of detection electrodes 21 and 22 of the detection unit 2 have higher detection sensitivity as the distance between adjacent electrode pairs is smaller. In the stacked sensor element 1, the distance between the electrode pairs can be adjusted by the thickness of the insulating sheet 12, and is, for example, in the range of 2 μm to 50 μm, preferably 4 μm to 20 μm. In the stacked sensor element 1, the interval between the electrode pairs can be set to be small, so that the number of electrode pairs arranged in the portion 10 to be deposited can be increased and the output sensitivity can be improved.

  The detection electrodes 21 and 22 are made of a material having both stability and conductivity in an environment exposed to the exhaust gas G. Specifically, a noble metal material such as Pt, Rh, or Au is used as a material for the detection electrodes 21 and 22. For example, a Pt-Rh alloy obtained by adding Rh to Pt has good stability in an oxidizing atmosphere. Yes, it is preferably used. The Rh content in the Pt-Rh alloy is selected, for example, in a range of 1% by mass to 50% by mass. The line width of the linear electrodes 21a and 21b can be adjusted by the thickness of the electrode films 210 and 220, and is appropriately selected in a range of, for example, 1 μm to 20 μm.

  The temperature measuring section 3 measures the temperature of the portion 10 on which the pair of detecting electrodes 21 and 22 of the detecting section 2 are arranged. The tip of two different types of metal wires 31 and 32 and a contact point 33 as a joining portion are arranged on the portion to be deposited 10 to form a thermocouple. The base ends of the metal wires 31 and 32 serving as open ends are connected to the first terminal 30a and the second terminal 30b of the pair of terminal portions 30, respectively, and further, via the pair of compensating wires 50a and 50b. , Is connected to the temperature detection unit 52 of the sensor control unit 5. As a result, a circuit in which the pair of metal wires 31 and 32 are connected is formed, and the distal end side of the sensor element 1 where the contact point 33 is located (that is, the temperature measurement region) and the base end side of the sensor element 1 (that is, the reference side) (A temperature range). By detecting the thermoelectromotive force in the sensor control unit 5, the temperature of the contact point 33, that is, the temperature of the portion 10 to be deposited can be detected.

  At this time, the first terminal 30a and the compensating lead 50a connected to the metal wire 31 serving as the + leg are made of the same metal material as the metal wire 31. Similarly, the first terminal 30b and the compensating lead 50b, which are connected to the metal wire 32 serving as the negative leg, are made of the same metal material as the metal wire 32. As a material of the metal wires 31 and 32, for example, an alloy material containing a noble metal such as Pt, Rh, or Au is used. Alternatively, the material is not limited to a noble metal or a noble metal alloy, and any metal alloy material having excellent stability in a use atmosphere and a use temperature range may be used. At the time of reproduction after PM detection, the temperature of the sensor element 1 becomes high. For example, it is desirable to use an alloy material that can be used stably at a high temperature of 800 ° C. or higher, preferably 1000 ° C. or higher.

  Specifically, a Pt-Rh alloy can be used as the metal wire 31 serving as the + leg, and Pt can be used as the metal wire 32 serving as the-leg, which is excellent in stability in an oxidizing atmosphere and at a high temperature. Alternatively, Pt-Rh alloys having different Rh contents can be combined as the metal wires 31 and 32. In this case, for example, the metal wire 31 serving as the + leg is a Pt-Rh alloy containing Rh in the range of 5% by mass to 50% by mass, preferably 10% by mass to 30% by mass, and the metal forming the − leg is used. The wire 32 is preferably a Pt-Rh alloy containing Rh in a range of 6% by mass or less.

As the metal wire 31 serving as the + leg and the metal wire 32 serving as the-leg, for example, the following combinations can be used.
+ Leg: Pd-Pt-Au alloy /-leg: Au-Pd alloy + leg: Mo-Ni alloy /-leg: Ni
+ Leg: Alumel (Ni-Al alloy) /-leg: Chromel (Ni-Cr alloy)
+ Leg: Nicrosil (Ni-Cr-S alloy) /-leg: Nissil (Ni-Si alloy)

  In the temperature measurement unit 3, the line width of the metal wires 31 and 32 can be adjusted by the thickness of the electrode films 310 and 320, and is appropriately selected in a range of, for example, 1 μm to 20 μm. The smaller the line width, the smaller the size of the contact 33, which is the junction, and the smaller the size of the contact 33, the higher the sensitivity of the thermocouple. By making the sensor element 1 a stacked type, the line width can be relatively easily reduced, preferably 1 μm to 10 μm, more preferably 1 μm to 5 μm. Thus, by controlling the size of the contact 33, the detection speed can be improved.

  In the sensor element 1 having the above-described configuration, the metal films 310 and 320 forming the temperature measuring unit 3 and the terminal unit 30, the metal film 210 forming the detecting unit 2, 220, the lead portions 21b, 22b, the terminal portion 20, and the heater electrode 41, the lead portions 42, 43, and the terminal portion 40 constituting the heater portion 4 are formed by printing in a predetermined shape, respectively, and are laminated in the order shown in FIG. Fired. As a result, the insulating element 11 is formed by integrating the insulating sheet 12 with the insulating base 11 and exposing the detecting section 2 and the temperature measuring section 3 on the side surface on the distal end side.

(Failure diagnosis of exhaust gas purification equipment)
Such a particulate matter detection sensor S is used for an exhaust gas purification device of an internal combustion engine E having a DPF 6 (see, for example, FIG. 4), and is disposed on the upstream side based on the output of the sensor element 1. The failure diagnosis of the DPF 6 can be performed. The operating state of the internal combustion engine E is controlled by the ECU 7 based on outputs from various sensors (not shown). The exhaust gas G containing particulate matter is discharged from the internal combustion engine E, and the DPF 6 installed in the exhaust gas passage E1 is disposed. Pass through. In general, when some abnormality occurs in the DPF 6, the trapping performance of the particulate matter is reduced, and the particulate matter leaks to the downstream side. Therefore, the presence or absence of abnormality in the DPF 6 can be determined by arranging the particulate matter detection sensor S downstream of the DPF 6 and monitoring its output.

  At this time, it is desired that the minute particulate matter leaking out of the DPF 6 be quickly detected using the particulate matter detection sensor S on the downstream side. The stacked sensor element 1 described above can detect the accumulation of finer particulate matter by reducing the distance between the pair of detection electrodes 21 and 22 of the detection unit 2. However, since the conductivity of the particulate matter mainly composed of soot has temperature dependency, it is necessary to correct the output of the detection unit 2 with temperature in order to detect the amount of deposited PM with higher accuracy. To this end, the ECU 7 includes a sensor control unit 5 that accurately measures the temperature of the detection unit 2 from the output of the temperature measurement unit 3 of the particulate matter detection sensor S and corrects the output of the detection unit 2 by temperature.

  Next, the details of the failure diagnosis processing of the DPF 6 performed by the sensor control unit 5 will be described. As shown in FIG. 6, when the failure diagnosis process of the DPF 6 is started, first, in step S100, the regeneration control of the particulate matter detection sensor S is performed. This regeneration control is performed by using the heater control unit 53 of the sensor control unit 5 to energize the heater unit 4 incorporated in the sensor element 1 and heat the detection unit 2. At this time, the amount of current supplied to the heater unit 4 is set so that the temperature of the portion 10 to be deposited is equal to or higher than the combustion temperature of the particulate matter (eg, 800 ° C. or higher). Then, the sensor element 1 is cooled. Thus, prior to the detection of the PM deposition amount by the detection unit 2, the particulate matter deposited on the deposition target portion 10 can be burned and removed, and the sensor element 1 can be regenerated.

Next, in step S101, the temperature detection value T _S by the temperature measurement unit 3 is read using the temperature detection unit 52 of the sensor control unit 5, and the temperature TG of the exhaust gas _G is compared. As the temperature _TG , for example, a value detected by a temperature sensor (not shown) provided in the exhaust gas passage E1 is read. If T _S ≤ _TG , the process proceeds to step S102. If _{T S>} T _G, until _{T S} ≦ _{T G,} repeats step S101. This step is for confirming the completion of the regeneration of the sensor element 1. Immediately after the regeneration, the detection accuracy of the detector 2 is reduced due to the effect of thermophoresis. This is because a temperature gradient is generated between the portion to be deposited 10 that has been heated and the temperature is high and the surroundings, and it becomes difficult for particulate matter to be deposited on the higher-temperature detector 2. The operation of the detection unit 2 is suspended until the condition is solved.

Here, the temperature measuring unit 3 of the sensor element 1, in the deposition unit 10, since it is disposed adjacent to the same plane and a pair of sensing electrodes 21 and 22 of the detection unit 2, the temperature detection value T _S is the deposition This accurately reflects the temperature of the unit 10, that is, the temperature of the detection electrodes 21 and 22. As shown in Figure 7, when the temperature T _G of the exhaust gas G experimentally varied, the change in the detected temperature value T _S, as compared with the detected temperature value T _C by the conventional sensor, responsive, follow Excellent in nature. The temperature detection by the conventional sensor can use, for example, a change in the heater resistance value of the heater unit 4 incorporated in the sensor element 1. In this case, the temperature can be detected from the temperature characteristic of the heater resistance value known in advance, but the detected temperature is the average temperature of the sensor element 1. Therefore, the temperature detection value T _R, to the temperature rise of the temperature T _G of the exhaust gas G, a delay, yet gentle rise in temperature, the maximum temperature is not reached highest temperature of the temperature T _G.

In contrast, the temperature detection value T _S, to the temperature rise of the temperature T _G of the exhaust gas G, not substantially delayed, yet rapidly increasing temperature, reaches a maximum temperature approximately equal to the temperature of the temperature T _G . As a result, the detection accuracy in step S101 can be improved, and whether or not the exhaust gas G has been cooled to the temperature _TG or lower, that is, the completion of the regeneration can be promptly determined, so that the time allotted to the PM detection in the subsequent steps can be extended. Thus, the accuracy of the failure diagnosis can be secured. Also, during regeneration control in step S100 also, since the temperature of the detecting portion 2 Dekiru temperature measuring directly, by monitoring the detected temperature value T _S, it is possible to ensure that unnecessary heating is not performed.

  That is, it is possible to control the heater unit 4 so that the detection unit 2 can be heated without excess or shortage and efficiently reach the predetermined temperature, and power consumption during reproduction can be reduced. As shown in Table 1 as a comparative example, in the regeneration of the detection unit 2 using the conventional sensor, the detection temperature (that is, the element average temperature) is controlled to be, for example, 800 ° C. However, actually, the temperature of the detection unit 2 to be energized becomes higher, for example, 920 ° C. In contrast, as shown in Table 1 as an example, in the configuration of the present embodiment, the temperature of the detection unit 2 can be directly detected. For example, when the detected temperature is 805 ° C., the element average temperature is 695 ° C. Was. By such control, power consumption is significantly reduced from 1.5 Wh in the comparative example to 1.0 Wh in the example. Further, the time required for heating and cooling can be reduced, and the time required for the entire failure diagnosis can be reduced.

In step S102, a voltage is applied to the detection unit 2 of the sensor element 1 to start PM detection. In this step, a predetermined detection voltage is applied between the pair of detection electrodes 21 and 22 of the detection unit 2, an electrostatic field is formed, and the particulate matter in the exhaust gas G is deposited. Next, proceeding to step S103, the output detection unit 51 of the sensor control unit 5 reads the PM accumulation amount as the sensor output value V of the detection unit 2. Further, the process proceeds to step S104, the temperature detection unit 52 of the sensor control unit 5 reads the detected temperature value T _S of the temperature measuring unit 3.

In the following step S105, the read sensor output value V is corrected according to the read temperature output value Ts. The sensor output value V is corrected as shown by the following equation because the conductivity of the collected particulate matter changes with temperature, and is set as the corrected sensor output value V1.
V1 = V × f (Ts)
In the formula, f (Ts) is a temperature correction function. For example, a temperature correction formula can be obtained based on a temperature characteristic of the sensor output value V measured in advance, and can be stored in the ECU 7 as a temperature correction table.

Then, in step S106, it determines the sensor output value V1 after correction, whether the threshold has been reached _{V R} set in advance (i.e., V1 ≧ _{V R).} If this step S106 is negative (i.e., V1 <V _R), the sensor output value V1 does not reach the threshold VR, i.e., it can be determined that abnormality of DPF6 has not occurred. In this case, the process returns to step S103, and the following steps are repeated.

If the step S106 is affirmative determination, the process proceeds to step S107, some abnormality occurs in DPF 6, it is determined that the particulate matter that exceeds the threshold value V _R to downstream leaked. In this case, for example, a malfunction lamp can be turned on to promptly notify the occupant.

Here, as shown in FIG. 8, when the temperature T _G of the exhaust gas G experimentally varied, the sensor output value V which is not temperature compensation varies greatly following the heating and cooling of the exhaust gas G. On the other hand, the sensor output value V1 after the correction in step S105 is almost constant with only a slight temperature change. This makes it possible to stably output the sensor output value V1 excluding the influence of the temperature, and perform an accurate failure diagnosis based on the PM accumulation amount.

(Embodiment 2)
As shown in FIG. 9 to FIG. 11 as a second embodiment, in the particulate matter detection sensor S, the sensor element 1 can be configured as a flat-shaped print-type sensor. In the first embodiment, the pair of electrodes 21 and 22 of the detection unit 2 are configured to be embedded in the insulating base 11 having a multilayer structure. In the present embodiment, the pair of electrodes 21 and 22 of the detection unit 2 are Printing is performed on the front surface (that is, the upper surface of the drawing) of the insulating substrate 11 that is to be the portion 10 to be deposited. A contact 33 is formed on the portion to be deposited 10 where the pair of tips 31a and 32a of the metal wires 31 and 32 constituting the temperature measuring section 3 and the pair of tips 31a and 32a are joined adjacent to the detection section 2. Are formed by printing.

  9 and 10, the detection electrodes 21 and 22 have a comb-like shape and include a plurality of linear electrodes 21a and 22a, respectively. The linear electrodes 21a and 22a having different polarities are alternately arranged in parallel to form a plurality of electrodes. Make up a pair. A pair of tips 31a and 32a of metal wires 31 and 32 are arranged in parallel on the sides of the detection electrodes 21 and 22, and the tips of the metal wires 31 located outside are bent in an L shape. , Are joined to the tip of the metal wire 32. In FIG. 11, the detection electrodes 21 and 22 are connected to the first terminal 20a and the second terminal 20b of the terminal unit 20 via lead portions 21b and 22b extending toward the base end, respectively. The metal wires 31 and 32 extend to the base end side of the lead portions 21b and 22b, and are connected to the first terminal 30a and the second terminal 30b of the terminal portion 30.

  The insulating base 11 is formed by laminating a flat insulating sheet 12a and a thicker flat insulating sheet 12b. The electrode films 210 and 220 serving as the detection electrodes 21 and 22 of the detection unit 2, the lead portions 21 b and 22 b, the metal films 310 and 320 serving as the metal wires 31 and 32 of the temperature measurement unit 3, and the terminal portions 20 and 30 are flat. The insulating sheet 12a is formed in a predetermined shape on the sheet surface by screen printing or the like. They are connected to each other via the provided through-hole TH5 or TH6, and are connected to the first terminal 20a and the second terminal 20b of the terminal section 20 in the uppermost layer.

  Above the insulating sheet 12a on which the detecting unit 2 and the temperature measuring unit 3 are printed, the insulating sheet 12a having a shorter length in the longitudinal direction X is exposed, and the sheet surface on the tip side of the insulating sheet 12a is exposed. Are arranged as follows. As a result, the sheet surface of the insulating sheet 12a exposed on the front end side of the insulating base 11 forms the portion 10 to be deposited, and a part of the metal films 310 and 320 disposed on the surface thereof 22, a pair of tip portions 31a and 32a are formed. In addition, the comb-shaped electrode films 210 and 220 form a pair of detection electrodes 21 and 22. Other portions are embedded between the two insulating sheets 12a.

  Below the insulating sheet 12a on which the detecting unit 2 and the temperature measuring unit 3 are disposed, an insulating sheet 12a constituting the heater unit 4 is disposed via an insulating sheet 12b. The heater section 4 has a heater electrode 41 arranged on the distal end side of the insulating sheet 12a, and the subsequent lead sections 42 and 43 are connected to the first terminal 40a and the second terminal 40bb of the terminal section 40 on the proximal end side. Connected to. The heater electrode 41, the lead portions 42 and 43, and the terminal portion 40 are formed by screen printing or the like.

  The constituent materials of the pair of detection electrodes 21 and 22 of the detection unit 2 and the metal wires 31 and 32 of the temperature measurement unit 3 can be the same as those in the first embodiment. Preferably, the pair of detection electrodes 21 and 22 of the detection unit 2 are formed of a noble metal material such as an Rh-Pt alloy, and the metal wires 31 and 32 of the temperature measurement unit 3 are formed of, for example, an Rh-Pt alloy. It can be composed of a combination of Pt or a noble metal material such as an Rh-Pt alloy having a different Rh content.

  In the detection unit 2, the interval between the linear electrodes 21a and 22a to be an electrode pair is appropriately selected in a range of, for example, about 40 μm to 200 μm. The line width of the linear electrodes 21a and 22a and the line width of the metal wires 31 and 32 of the temperature measuring unit 3 are set in a range that can be formed by screen printing or the like, and are, for example, about 1 μm to 5 mm, preferably about 20 μm to 200 μm. Is appropriately selected within the range.

Also in the configuration of the present embodiment, the detection unit 2 and the temperature measurement unit 3 are arranged adjacent to the deposition unit 10, so that the temperature of the deposition unit 10 can be accurately grasped from the temperature detection value T _S by the temperature measurement unit 3. The temperature of the sensor output value V of the detection unit 2 can be accurately corrected. Therefore, the failure diagnosis of the DPF 6 using the particulate matter detection sensor S can be performed efficiently and accurately in a short time.

  Note that, among the reference numerals used in the second and subsequent embodiments, the same reference numerals as those used in the above-described embodiments represent the same components and the like as those in the above-described embodiments unless otherwise specified. The same applies to the reference numerals in the figure.

(Embodiment 3)
As shown in FIGS. 12 to 14 as a third embodiment, in the particulate matter detection sensor S using the stacked sensor element 1, the arrangement of the temperature measurement unit 3 can be changed. In the first embodiment, the temperature measurement unit 3 is configured to overlap the upper layer of the pair of electrodes 21 and 22 of the detection unit 2, but in the present embodiment, a layer common to a part of the detection electrodes 21 and 22 is provided. The temperature measuring unit 3 is configured. Here, as shown in FIGS. 12 and 13, a set of linear electrodes 21 c and 22 c constituting the detection electrodes 21 and 22 and a metal of the temperature measurement unit 3 are provided at the center of the detection unit 2 in the stacking direction Y. The lines 31 and 32 are juxtaposed at intervals in the longitudinal direction X.

  Specifically, the lengths of the linear electrodes 21c and 22c in the longitudinal direction X are shorter than the linear electrodes 21a and 22a located above and below the linear electrodes 21c and 22c, and are disposed on the distal end side. A pair of distal ends 31a, 32a of metal wires 31, 32 constituting the temperature measuring unit 3 are respectively arranged adjacent to the base ends of the linear electrodes 21c, 22c. The edge portions of the pair of tip portions 31a and 32a are joined by an extended portion 34 formed on the side surface of the insulating substrate 1 by coating. The extension portion 34 is made of one of the metal wires 31 and 32, here, the same metal material as the metal wire 32. The tip of the extension portion 34 and the tip 31a of the metal wire 31 are connected to each other, 33 are formed.

  As shown in FIG. 14, metal wires 31 and 32 are formed on a set of insulating sheets 12 at the center where the linear electrodes 21 c and 22 c are arranged. The metal films 310 and 320 are printed and formed in a substantially symmetrical shape, and are connected to the first terminal 30a and the second terminal 30b of the terminal unit 30 via the through holes TH1 and TH2 on the base end side. The other configurations of the detection unit 2 and the heater unit 4 are the same as those in the first embodiment, and a description thereof will be omitted.

  According to the particulate matter detection sensor S of the present embodiment, the same effect as in the above embodiment can be obtained. Further, according to the above configuration, it is not necessary to separately provide the insulating sheet 12 for forming the temperature measuring unit 3, so that the number of stacked insulating sheets 12 can be reduced. Thereby, the thickness of the insulating base 1 in the stacking direction Y is reduced, and the sensor element 1 can be made smaller.

(Embodiment 4)
As shown in FIGS. 15 and 16 as a fourth embodiment, in the particulate matter detection sensor S using the print-type sensor element 1, the arrangement of the temperature measuring unit 3 can be changed as in the third embodiment. . In the second embodiment, the temperature measurement unit 3 is disposed in parallel to the side of the pair of electrodes 21 and 22 of the detection unit 2. However, in the present embodiment, the temperature measurement unit 3 is located closer to the base end than the detection electrodes 21 and 22. The metal wires 31 and 32 of the warm part 3 are arranged. Specifically, on the surface of the insulating substrate 1, a pair of tip portions 31 a of the metal wires 31 and 32 are positioned so that the temperature measurement unit 3 is located between the lead portions 21 b and 22 b of the detection electrodes 21 and 22. 32a is formed by printing. At this time, for example, the distal end portion 31a of the metal wire 31 is bent and connected to the metal wire 32, and the contact 33 is formed at the joint. The other configurations of the detection unit 2 and the heater unit 4 are the same as those of the second embodiment, and the description is omitted.

  According to the particulate matter detection sensor S of the present embodiment, the same effect as in the above embodiment can be obtained. Further, in the above configuration, the number of the linear electrodes 21a and 22a forming the pair of detection electrodes 21 and 22 can be increased as compared with the second embodiment. Here, for example, four linear electrodes 21a and 22a are arranged in the width direction of the insulating base 1, respectively, so that the sensitivity of the detection unit 2 can be improved.

(Embodiment 5)
As shown as a fifth embodiment in FIGS. 17 to 20, in the particulate matter detection sensor S using the stacked sensor element 1, a pair of tip portions 31 a of the metal wires 31 and 32 constituting the temperature measuring unit 3 are provided. One of the detectors 32a may be provided in common with the detector 2. In the first embodiment, the temperature measurement unit 3 is independently disposed so as to be an upper layer of the pair of electrodes 21 and 22 of the detection unit 2. However, in the present embodiment, the linear shape of the detection electrodes 21 and 22 is formed. One of the electrodes 21a and 22a also serves as the tip 31a of the metal wire 31 of the temperature measuring section. The other basic configurations of the detection unit 2 and the heater unit 4 are the same as those in the first embodiment, and the following description will focus on the differences.

  Here, in the first embodiment (see FIGS. 1 to 3), of the linear electrodes 21 a and 22 a forming the pair of detection electrodes 21 and 22, for example, the linear electrode forming the ground-side detection electrode 22 is used. One of the wires 22 a is used as the metal wire 31 of the temperature measuring unit 3. Then, the metal wire 32 of the temperature measuring section 3 is arranged in parallel on the base end side of the linear electrode 22a. Specifically, as shown in FIGS. 17 and 18, the linear electrode 22 a also serving as the metal wire 31 is replaced with the linear electrode located at the center of the three linear electrodes 21 a constituting the detection electrode 22. 22a. Then, the metal wire 32 of the temperature measuring unit 3 is arranged on the base end side of the linear electrode 22a. The linear electrode 22a and the metal wire 32 exposed on the portion to be deposited 10 form a continuous line extending in the longitudinal direction X, and a contact point 33 is formed at the joint.

  As shown in FIG. 19, the insulating sheet 12 constituting the insulating base 1 includes the insulating sheet 12 disposed at a substantially central portion in the stacking direction and the three linear electrodes 22 a of the detection electrodes 22. The electrode film 220 serving as the linear electrode 22a also serving as the metal wire 31 is formed by printing, and the metal film 320 serving as the metal wire 32 is formed by printing on the base end side. The linear electrode 22a also serving as the distal end 31a of the metal wire 31 is connected to another linear electrode 22a via a through hole TH3, and further connected to a second terminal 20b via a lead 22b and a through hole TH6. Is done. The other end of the metal film 320 forming the metal wire 32 extends to the base end side, and is connected to the second terminal 30b of the temperature measuring unit 3 through the through hole TH2. In FIG. 3, the insulating sheet 12 on which the metal films 310 and 320 to be the metal wires 31 and 32 are formed by printing is not arranged.

  At this time, the second terminal 20b of the detection unit 2 to which the linear electrode 22a is connected also serves as the first terminal 30a of the temperature measurement unit 3. That is, as shown in FIG. 20, the pair of terminals 20 of the detection unit 2 are connected to the output detection unit 51 of the sensor control unit 5, and the second terminal 20b of which is connected to the temperature through the compensating conductor 50a. Connected to the detection unit 52. A second terminal 30b connected to the metal wire 32 is connected to the temperature detecting section 52 via a compensating lead 50b to form a pair of terminal sections 30. By using the linear electrode 22 a connected to the ground-side second terminal 20 b as the metal wire 31, it is generated at the contact point 33 of the metal wires 31 and 32 without being affected by the voltage applied to the detection unit 2. Thermoelectromotive force can be detected.

  As in the first embodiment, a series of wiring sections from the metal wires 31 and 32 constituting the temperature measuring section 3 to the sensor control section 5 are made of the same metal material. That is, the second terminal 20b connected to the linear electrode 22a also serving as the metal wire 31 and the compensating lead 50a are made of the same metal material as the linear electrode 22a, for example, a Pt-Rh alloy. The metal wire 32, the second terminal 30b connected thereto, and the compensating lead wire 50b are made of a metal material different from the metal wire 31, for example, Pt or a Pt-Rh alloy having a different Rh content from the linear electrode 21a. It is desirable to use and configure.

  According to the particulate matter detection sensor S of this embodiment, the same effect as that of the above embodiment can be obtained with a more compact structure. In the above configuration, one of the pair of tip portions 31a and 32a of the pair of metal wires 31 and 32 of the temperature measuring unit 3 is also used as one of the linear electrodes 21a and 22a forming the pair of detection electrodes 21 and 22. Since one of the pair of terminal portions 30 also functions as one of the pair of terminal portions 20, the configuration is further simplified. That is, since the temperature measuring section 3 is integrally formed with the detecting section 2, the number of laminated insulating sheets 12 constituting the insulating base 1 can be reduced, and furthermore, the terminal section can be shared to form a wiring structure. Is simplified, so that the size can be further reduced.

(Embodiment 6)
As shown in FIG. 21 and FIG. 22 as a sixth embodiment, in the particulate matter detection sensor S using the print-type sensor element 1, one of the metal wires 31 and 32 constituting the temperature measurement unit 3 is connected to the detection unit 2 Can also be provided in common. In the fourth embodiment, the metal films 310 and 320 that become the pair of metal wires 31 and 32 that become the temperature measuring unit 3 are independently disposed on the base end side of the detecting unit 2. One of the pair of detection electrodes 21 and 22 arranged on one deposition target portion 10 also serves as the tip 31a of the metal wire 31 of the temperature measurement unit. The other basic configurations of the detection unit 2 and the heater unit 4 are the same as those of the fourth embodiment, and the following description will focus on the differences.

  Here, in the fourth embodiment (see FIGS. 15 and 16), a part of the detection electrode 22 on the ground side is used as the tip 31a of the metal wire 31 of the temperature measuring unit 3. Specifically, as shown in FIG. 21, in the comb-shaped detection electrode 22 composed of a plurality of linear electrodes 22a arranged in parallel and a linear connecting portion 22c, the base end of the linear electrode 22a is The connection part 22 c to be connected is used as the tip part 31 a of the metal wire 31. Then, the distal end 32a of the metal wire 32 extending in the longitudinal direction X is connected from the proximal end to an intermediate position between the side edges of the connecting portion 22c extending in a direction orthogonal thereto, and the contact with the connecting portion 22c is established. 33 are formed.

  As shown in FIG. 22, the base end of the metal wire 32 extends to the base end side of the insulating base 1 and is connected to the second terminal 30b of the temperature measuring unit 3. The connection part 22c of the detection electrode 22 also serving as the metal wire 31 is connected to the lead part 22b, and the lead part 22b is connected to the second terminal 20b of the detection part 2. The second terminal section 20b also serves as the first terminal 30a of the temperature measuring section 3. The detection electrode 21 is connected to a first terminal 20a of the detection unit 2 via a lead 22a.

  Also in this embodiment, a series of wiring sections from the metal wires 31 and 32 constituting the temperature measuring section 3 to the sensor control section 5 are made of the same metal material as in the above-described fifth embodiment. The metal wire 31 is also used as a part of the detection electrode 22 and the terminals 20 and 30 are partly shared. Thus, the same effect can be obtained with a simple structure.

(Embodiment 7)
As shown in FIG. 23 as a seventh embodiment, in the particulate matter detection sensor S using the stacked sensor element 1, the temperature measuring section 3 can be formed on the tip end surface. In each of the above embodiments, the deposited portion 10 of the sensor element 1 is provided on the side surface on the distal end side of the insulating base 1. The temperature measuring unit 3 may be arranged adjacently. Specifically, the linear electrodes 21a and 22a to be the pair of detecting electrodes 21 and 22 of the detecting unit 2 are alternately arranged in parallel in the stacking direction Y, and outside the linear electrodes 21a and 22a (that is, FIG. ), A pair of tip portions 31a, 32a of metal wires 31, 32 having the same shape are arranged in parallel. After lamination, the pair of tip portions 31a and 32a are connected by applying and forming an extension portion 34 made of the same metal material as one of the metal wires 31 and 32, and a contact point 33 is formed at a joint portion of a dissimilar metal. You.

  According to this embodiment, effects similar to those of the above embodiment can be obtained. Thus, the portion to be deposited 10 may be disposed on the tip side of the sensor element 1, and the pair of tips 31 a, 32 a of the metal wires 31, 32 of the temperature measuring section 3 and the contact point 33 are connected to the portion to be deposited. By arranging at 10, the temperature detection of the detection unit 2 can be performed with high accuracy. Further, in the present embodiment, the metal wires 31 and 32 constituting the temperature measuring unit 3 are arranged independently of the detecting unit 2, but one of the pair of tips 31 a and 32 a of the metal wires 31 and 32 is detected. It can be provided in common with at least a part of the detection electrodes 21 and 22 of the section 2.

The present invention is not limited to the above embodiments, and can be applied to various embodiments without departing from the gist thereof.
For example, in the above embodiment, the number of the linear electrodes 21a and 22a constituting the detection electrodes 21 and 22 of the detection unit 2 is three or four, but the number, shape, and arrangement of the linear electrodes 21a and 22a are set. Can be changed as appropriate. In accordance with this, the shape of the insulating base 1 constituting the sensor element 1, the number of laminated insulating sheets 12, the configuration of the heater section 4, and the like can be changed.

  Using such a particulate matter detection sensor S, a failure diagnosis of the DPF 6 arranged upstream can be performed quickly and with high accuracy. In particular, based on the temperature detected by the temperature measuring unit 3, the temperature of the detecting unit 2 can be controlled with high accuracy using the heater unit 4 and the detection result can be corrected for temperature, so that very small particulate matter is very slightly discharged. Even if it happens, it can be detected immediately.

  The configuration of the particulate matter detection sensor S and the exhaust gas purification device using the same is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, the assembling structure of the sensor element 10 of the particulate matter detection sensor S, the shape of the cover S1 covering the sensor element 10, the configuration and material of each part, and the like can be arbitrarily set.

  In the above embodiment, the internal combustion engine E is a diesel engine, and the DPF 6 for collecting particulate matter is arranged. However, the internal combustion engine E may be a gasoline engine and a gasoline particulate filter may be arranged. In addition, the present invention is not limited to the combustion exhaust gas of the internal combustion engine E, and can be applied to any measurement gas containing particulate matter.

E1 Exhaust gas passage S Particulate matter detection sensor 1 Sensor element 10 Deposited part 2 Detection part 21, 22 Detection electrode 3 Temperature measurement part 31, 32 Metal wire 33 Contact 5 Sensor control part

Claims (13)

A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3) ,
As for the pair of metal wires, at least in a portion where the sensor element is exposed to the gas to be measured (G), a portion excluding the pair of ends is buried inside the sensor element. Sensor. A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3),
The sensor element has an insulating substrate (11) formed of a laminate of a plurality of insulating sheets (12), and the sensor element is formed on a surface of the insulating substrate formed of a stacked surface of the plurality of insulating sheets. Part is formed,
Between the two insulating sheets adjacent to each other, the metal films (310, 320) constituting the pair of metal wires are buried, and the edge of the metal film exposed to the portion to be deposited is A particulate matter detection sensor constituting the pair of ends . A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3),
The sensor element has an insulating base (11) composed of a laminate of a plurality of insulating sheets (12a, 12b), and the sheet of the insulating sheet (12a) serving as a surface of the insulating base (11). A metal film (310, 320) constituting the pair of metal wires is disposed on a surface, and a part of the metal film disposed on the deposition target portion provided on the sheet surface is a part of the pair of metal wires. A particulate matter detection sensor constituting an end . A particulate matter detection sensor (S) including a sensor element (1) arranged in a gas path to be measured (E1),
The sensor element is
A deposition portion (10) on which particulate matter contained in the gas to be measured (G) is deposited;
A detection unit (2) for detecting particulate matter deposited on the portion to be deposited;
A pair of metal wires (31, 32) made of dissimilar metals, a pair of ends (31a, 32a) of the pair of metal wires disposed on the portion to be deposited, and a contact point where the pair of ends are joined. (33) having a temperature measuring section (3),
The detection section has a pair of detection electrodes (21, 22) arranged apart from each other in the portion to be deposited, and one (31) of the pair of metal wires is connected to the pair of detection electrodes. And one of the pair of sensing electrodes is a ground electrode, and is formed of a metal material having the same composition as one of the pair of metal wires. Substance detection sensor. The detection unit has a pair of detection electrodes (21, 22) arranged apart from each other in the portion to be deposited, and the pair of ends is disposed adjacent to the pair of detection electrodes. The particulate matter detection sensor according to any one of claims 1 to 3, wherein the detection is performed. The particulate matter detection sensor according to claim 1, wherein at least one of the pair of metal wires is made of a noble metal or an alloy containing a noble metal . The pair of metal wires include a metal wire (32) made of a Pt-Rh alloy having a Pt or Rh content of less than 10% by mass and a metal wire (31) made of a Pt-Rh alloy having a Rh content of 10% by mass or more. The particulate matter detection sensor according to any one of claims 1 to 6, wherein Includes a particulate matter detection sensor as claimed in any one of 請 Motomeko 1-7, the sensor control unit (5),
The sensor element includes the portion to be deposited on the tip side in the longitudinal direction (X),
Ends of the pair of metal wires opposite to the contact point are connected to a pair of temperature measurement terminals (30) provided on a base end side of the sensor element.
The particulate matter detection device, wherein the sensor control unit includes a temperature detection unit (52) connected to the pair of temperature measurement terminals and detecting an electromotive force between the pair of temperature measurement terminals. . The pair of metal wires include a metal wire (31) connected from the contact to the first terminal (30a) of the pair of temperature measurement terminals, and a metal wire (31) connected from the contact to the pair of temperature measurement terminals. The metal wire (32) connected to the second terminal (30b) among them, wherein each metal wire is made of a metal material having the same composition from the contact to each terminal. Particulate matter detection device. The temperature detector (52) and the pair of temperature measuring terminals are connected by a pair of compensating leads (50a, 50b), and each compensating lead is connected to the first compensating lead. The particulate matter detection device according to claim 9, wherein the particulate matter detection device is made of a metal material having the same composition as the terminal or the second terminal . 11. The sensor control unit according to claim 8, further comprising: an output detection unit configured to read an output signal of the detection unit, and correcting the output signal based on a detection result of the temperature detection unit. 2. The particulate matter detection device according to claim 1. The sensor element has a built-in heater unit (4), and the sensor control unit includes a heater control unit (53) that controls the operation of the heater unit based on a detection result of the temperature detection unit . The particulate matter detection device according to any one of claims 8 to 11 . The particulate matter detection device according to any one of claims 8 to 12, wherein the measured gas passage (E1) is an exhaust gas passage of an internal combustion engine, and the measured gas is exhaust gas of an internal combustion engine .

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