JP6711846B2 - Parts for measuring devices of particulate matter - Google Patents

Description

The present disclosure relates to parts for a measuring device for particulate matter.

As a particulate matter measuring device component used for measuring the amount of particulate matter in exhaust gas discharged from a diesel engine, for example, JP-A-2014-159783 (hereinafter, also referred to as Patent Document 1) Those described in are known. The particulate matter measuring device component described in Patent Document 1 has a filter divided into a plurality of cells by a porous partition wall, and when at least one cell is used as a measuring cell, the cell is sandwiched. And a pair of electrodes provided on the. Then, in the particulate matter measuring device component described in Patent Document 1, the deposition amount of the particulate matter in the exhaust gas collected by the filter is calculated based on the capacitance between the pair of electrodes. Further, the flow path and the filter are arranged in parallel with each other, and a part of an opening on the gas outflow side of the flow path is closed, and another flow path is closed on the gas inflow side.

A part for a device for measuring particulate matter has a base part made of ceramics having a flow passage space open at the surface at both ends, and a flow passage through which a gas flows by dividing the flow passage space into a plurality of parts. In a region facing each other across the flow path space of the base portion and a filter portion made of a porous ceramics provided in the space, end portions of the portions provided along each of the plurality of filter portions, The filter unit has a meander-shaped linear wiring pattern that is connected and meandered, and is provided with a pair of electrodes for capacitance formation provided along the filter unit so as to sandwich the filter unit. Includes those arranged at an angle with respect to the length direction of the flow path space.

Further, another particulate matter measuring device component is a plate-shaped member made of ceramics and has a pair of bases juxtaposed so that their main surfaces face each other, and a flow path space between the pair of bases. A filter part made of porous ceramics provided so as to divide to form a flow path, and the pair of base parts are connected to each other to connect the end parts of the parts provided along each of the plurality of filter parts to meander. And a pair of electrodes for capacitance formation provided along the filter portion so as to sandwich the filter portion, and the filter portion is provided with the meander-shaped linear wiring pattern. It includes those arranged at an angle with respect to the length direction of the road space.

It is a perspective view of parts for measuring devices of particulate matter. It is sectional drawing which shows the cross section of the component for measuring devices of a particulate matter shown in FIG. It is sectional drawing which shows the vertical cross section of the component for measuring devices of a particulate matter shown in FIG. It is sectional drawing which shows the cross section of another example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the cross section of another example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the cross section of another example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the cross section of another example of the components for measuring devices of a particulate matter. It is a schematic diagram which shows the wiring pattern of the electrode in the component for measuring devices of a particulate matter shown in FIG. It is a schematic diagram which shows the wiring pattern of the electrode in the other example of the components for measuring devices of a particulate matter. It is a schematic diagram which shows the wiring pattern of the electrode in the other example of the components for measuring devices of a particulate matter. It is a schematic diagram which shows the wiring pattern of the electrode in the other example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the vertical cross section of another example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the vertical cross section of another example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the vertical cross section of another example of the components for measuring devices of a particulate matter. It is sectional drawing which shows the vertical cross section of another example of the components for measuring devices of a particulate matter. (A) is a top view of the other example of components for measuring devices of particulate matter, (b) is a side view, and (c) is a front view. It is a schematic diagram which shows the manufacturing method of the component for measuring devices of a particulate matter.

Hereinafter, the particulate matter measuring device component 100 will be described with reference to the drawings. In FIG. 1 and the like, a Cartesian coordinate system xyz defined by being fixed to the particulate matter measuring device component 100 is attached. In the following description, the direction may be described with reference to this coordinate system. In the particulate matter measuring device component 100, any direction may be a vertical direction or a horizontal direction. Further, the z-axis direction may be referred to as a vertical direction, a height direction, or a thickness direction. Further, when the component 100 for a measuring device for particulate matter is simply referred to as a plan view, it means that it is seen from the z-axis direction.

As shown in FIGS. 1 and 2, a particulate matter measuring device component 100 includes a base portion 1 having a flow passage space 10 therein, and a filter portion 2 provided inside the flow passage space 10. .. The flow path space 10 is divided into a plurality of sections by the filter section 2 to form a plurality of flow paths 11. As shown in FIG. 3, the particulate matter measuring device component 100 further includes a pair of electrodes 3 for capacitance formation on the base 1. The particulate matter measuring device component 100 is used, for example, to measure the amount of particulate matter in exhaust gas discharged from a diesel engine.

The base portion 1 is a member for forming a flow passage 11 (flow passage space 10) through which gas flows. The base 1 is made of, for example, an insulating ceramic such as alumina. The base 1 has, for example, one or a plurality of flow passage spaces 10 inside. In the particulate matter measuring device component 100 shown in FIG. 1, the base 1 has a rectangular parallelepiped outer shape and has two flow passage spaces 10 therein. The flow path space 10 extends along the longitudinal direction of the main surface of the base 1. Each flow path space 10 is divided into a plurality of parts by the filter portion 2, and each of the divided spaces is a flow path 11. The two flow path spaces 10 are arranged in the thickness (height) direction of the base 1. The base portion 1 has, for example, a length in the longitudinal direction of the main surface, a length between the side surfaces having an opening (depth, length in the y-axis direction) of 40 mm, a length in the lateral direction, and a side surface having no opening. The length (width, length in the x-axis direction) can be set to 10 mm, and the height (thickness, length in the z-axis direction) can be set to 5 mm.

The flow path space 10 extends from one side surface of the base 1 to a side surface at a position facing the side surface. The flow path space 10 is open to one side surface of the base 1 and a side surface at a position facing the side surface. The flow path 11 is also open to one side surface of the base 1 and the side surface at a position facing the side surface. One of the two openings is an inflow port 4 through which gas flows, and the other is an outflow port 5 through which gas flows out of the flow path 11. Note that, in FIG. 2, a white arrow indicates a gas flow. Further, the flow path space 10 can be set to have a width (length in the x-axis direction) of 8 mm and a height (distance between the bottom surface and the ceiling surface, length in the z-axis direction) of 1.2 mm. The length of the flow path space 10 (the length in the y-axis direction) is equal to the length of the base 1, and can be set to 40 mm.

The filter part 2 is a member for collecting the particulate matter in the gas. As shown in FIGS. 2 and 3, the filter unit 2 is provided inside the flow path space 10. As shown in FIG. 2, in the particulate matter measuring device component 100 of the present disclosure, the filter portion 2 is plate-shaped, and the plurality of flow passage spaces 10 in the base portion 1 are arranged in the width direction of the flow passage space 10. Multiple areas are provided so as to be divided into areas. The filter unit 2 includes the filter unit 2 arranged so as to be inclined with respect to the length direction (y-axis direction) of the flow channel space 10. In the example shown in FIG. 2, all the filter units 2 are arranged to be inclined with respect to the length direction (y-axis direction) of the flow path space 10. The length direction of the flow path space 10 is the direction from the inflow port 4 to the outflow port 5. In the particulate matter measuring device component 100 of the present disclosure, five filter portions 2 are provided for each flow path space 10. Each of the five filter units 2 is arranged in parallel. The filter part 2 is made of porous ceramics. Examples of porous ceramics include porous alumina. Since the filter part 2 is made of porous alumina, the gas flowing through the flow path 11 can pass through the filter part 2. At this time, the filter unit 2 can collect (deposit) a part of the particulate matter contained in the gas. And since the filter part 2 is arrange|positioned inclining with respect to the length direction of the flow path space 10, the length direction of the flow path space 10 is set to the flow direction of the exhaust gas which flowed in the exhaust pipe. When the particulate matter measuring device component 100 is arranged so as to be parallel to each other, the filter unit 2 is inclined with respect to the gas flow. Therefore, the gas easily flows into the filter unit 2, the particulate matter contained in the gas is easily collected, and the detection sensitivity of the particulate matter becomes high.

The flow channel 11 provided by being divided by the filter unit 2 has a width (a length between the filter units 2) of 1.2 mm and a height (a distance between the bottom surface and the ceiling surface) of 1. It can be set to 2 mm. The dimensions of the filter portion 2 are, for example, equal to the length of the base portion 1 in the width direction of 0.3 mm and the length of the base portion 1 in the thickness direction equal to the distance between the bottom surface and the ceiling surface of the flow passage 11. The length along the length direction of the base 1 can be set to 0.2 mm and 40 mm. The inclination angle θ of the filter portion 2 with respect to the length direction (y-axis direction) of the flow path space 10 may be set to, for example, 3° to 10°.

In the example shown in FIGS. 4 and 5, as compared with the example shown in FIG. 2, between the pair of adjacent filter portions 2, one end is connected to the end portion of the one filter portion 2 on the inflow port 4 side, and the other. The filter portion 2 is provided, the end portion of which is connected to the end portion on the outflow port 5 side of the other filter portion 2. In other words, the filter portion 2 has a zigzag shape, and the bent portions are alternately located at the inflow port 4 and the outflow port 5. As a result, the flow passage 11 is divided by the filter unit 2 into a first flow passage 11a connected to the inflow port 4 into which the gas flows and a second flow passage 11b connected to the outflow port 5 from which the gas flows out. There is. The width of the first flow passage 11a decreases toward the length direction from the inflow port 4, and the width of the second flow passage 11b increases toward the flow outlet 5 in the length direction.

With such a configuration, all of the gas flowing from the inflow port 4 into the first flow path 11a passes through the filter unit 2, flows through the second flow path 11b, and flows out through the outflow port 5. Therefore, the collection efficiency of the particulate matter is further improved, and the detection sensitivity of the particulate matter is further improved. In the conventional part for measuring particulate matter, a part of the opening is closed by the closing member, whereas the inlet 4 and the outlet 5 are not closed. A portion (a bent portion of the zigzag-shaped filter portion 2) connected to the inlet 4 and the outlet 5 of the filter portion 2 also serves as a closing member. Since the inflow port 4 and the outflow port 5 are not closed, the ratio of the area of the inflow port 4 and the outflow port 5 to the opening area of the flow path space 10 is large. Therefore, the inflow amount of the exhaust gas containing the particulate matter becomes large, and the collection efficiency of the particulate matter becomes high. Then, it is possible to obtain a smaller particle component measuring device component 100.

In the example shown in FIG. 4, the filter unit 2 is arranged so as to be inclined with respect to the length direction of the flow channel space 10, and is arranged along (parallel to) the length direction of the flow channel space 10. And the filter portions 2 that are present, and these are arranged alternately. On the other hand, in the particulate matter measuring device component of the example shown in FIG. 5, all the filter parts 2 are arranged to be inclined with respect to the length direction of the flow path space 10. The adjacent filter units 2 are inclined in different directions. Since all the filter parts 2 are inclined with respect to the length direction of the flow path space 10, the length of the filter parts 2 can be increased, the collection efficiency of particulate matter can be further improved, and the detection of particulate matter can be performed. The sensitivity is improved. In the examples shown in FIGS. 4 and 5, the filter portion 2 is also arranged at the outermost portion in the width direction of the flow channel space 10 and covers the inner surface of the base portion 1 facing the flow channel space 10. With such a configuration, a larger amount of particulate matter can be collected. In the particulate matter measuring device component of the example shown in FIG. 5, it is described above that all the filter parts 2 are arranged to be inclined with respect to the length direction of the flow channel space 10. However, in this case All the filter parts 2 refer to all the filter parts other than the filter part that covers the inner surface of the base part 1.

In the examples shown in FIGS. 4 and 5, the shapes of the first flow channel 11a and the second flow channel 11b in plan view, and the shapes of the bottom surface and the ceiling surface of the first flow channel 11a and the second flow channel 11b are It is a triangle. On the other hand, in the particulate matter measuring device component 100 of the example shown in FIG. 6, the shape of the first flow path 11a is a trapezoid. In the example of the triangular first flow path 11a of the example shown in FIG. 5, it has a shape like a corner of the outlet port 5 side is cut off. It can be said that the bent portion on the outflow port 5 side is bent in two steps, and the bent portion has a portion extending in the width direction of the flow path space 10. With such a configuration, it is possible to increase the area of the portion of the filter portion 2 that faces the first flow path 11a on the inflow side, and thus it is possible to collect more particulate matter. The particulate matter collection efficiency is further improved, and the particulate matter detection sensitivity is further improved. In addition, since the corner portion has an obtuse angle, cracking of the filter portion 2 starting from the corner portion is less likely to occur. In this respect, similarly, in the second flow passage 11b, it is preferable that the triangular shape of the second flow passage 11b has a trapezoidal shape in which a corner portion on the inflow port 4 side is cut into corners. In this case, from the viewpoint of the collection efficiency of the particulate matter, the width of the first flow channel 11a is set to the width of the second flow channel 11b as in the case of the particulate matter measuring device component 100 of the example shown in FIG. It should be larger than the width of.

The particulate matter measuring device component 100 of the example shown in FIG. 7 has a shape in which the corner portion of the triangular first flow channel 11a of the example shown in FIG. In other words, the corner of the bent portion of the zigzag-shaped filter portion 2 on the side of the flow channel 11 (first flow channel 11a) is rounded. It can also be said that the corner portion on the outlet 5 side of the first flow channel 11a in the component 100 for a measuring device for particulate matter of the example shown in FIG. 6 is rounded. Therefore, similarly, the area of the part of the filter portion 2 facing the first flow path 11a on the inflow side can be increased, so that more particulate matter can be collected and the particulate matter can be collected. Efficiency is further improved. The detection sensitivity of particulate matter is further improved. And since it does not have a corner, a crack of the filter part 2 which originates in a corner becomes more difficult to occur. In this respect, similarly, in the second flow passage 11b, it is preferable that the corner portion of the triangular second flow passage 11b on the side of the inflow port 4 is rounded. Also in this case, similarly, from the viewpoint of collection efficiency of the particulate matter, it is preferable to make the width of the first flow passage 11a larger than the width of the second flow passage 11b. In the particulate matter measuring device component 100 of the example shown in FIG. 7, the outermost portion of the filter portion 2 in the width direction of the flow channel space 10 faces the flow channel space 10 of the base 1. The inner surface is covered, and the surface on the flow path 11 (first flow path 11a) side is inclined with respect to the length direction of the flow path space 10. It is said that this portion is also arranged to be inclined with respect to the length direction of the flow path space 10.

Here, in the particulate matter measuring device component 100 of the present disclosure, the wall surface of the channel 11 of the base portion 1 is denser than the surface of the filter portion 2. This makes it difficult to deposit particulate matter on the wall surface of the flow path 11 of the base portion 1 and facilitates depositing particulate matter on the surface of the filter portion 2. As a result, the deposition of the particulate matter can be easily concentrated on the filter unit 2, so that the linearity between the deposition amount of the particulate matter and the measured value can be increased. As a result, the measurement accuracy of the particulate matter measuring device component 100 can be improved.

The fact that the wall surface of the channel 11 of the base portion 1 is denser than the surface of the filter portion 2 can be confirmed, for example, by the following method. Specifically, the wall surface of the flow path 11 of the base portion 1 and the surface of the filter portion 2 are observed using a scanning electron microscope (SEM). Then, the obtained SEM image is subjected to image processing to obtain the porosity of the surface. As a result, smaller porosity can be considered more dense. The porosity of the wall surface of the flow path 11 of the base 1 can be set to 3% or less, for example. The porosity of the surface of the filter part 2 can be set to 40 to 70%, for example. In addition, the wall surface of the flow path 11 referred to here means the entire inner surface of the base 1 facing the gas in the flow path 11. That is, the ceiling surface and the bottom surface are included in the wall surface here.

By setting the porosity of the wall surface of the flow path 11 of the base 1 to 3% or less, it is possible to make it difficult for the particulate matter to enter the inside of the base 1. As a result, it is possible to reduce the possibility that the particulate matter adheres to the electrodes 3, and therefore the possibility that the electrostatic capacitance between the electrodes 3 cannot be correctly measured due to the adherence of the particulate matter to the electrodes 3. It can be reduced. As a result, the measurement accuracy of the particulate matter measuring device component 100 can be further improved.

The base portion 1 and the filter portion 2 are integrally formed. By integrally forming the base portion 1 and the filter portion 2, long-term reliability of the particulate matter measuring device component 100 can be improved. Specifically, when the base portion 1 and the filter portion 2 are separately formed and then joined, for example, peeling may occur from the interface between the base portion 1 and the filter portion 2. In particular, when a joining material or the like is used for joining, there is a possibility that the filter portion 2 cannot be correctly fixed to the base portion 1 due to deterioration of the joining material. On the other hand, by integrally forming (baking) the base portion 1 and the filter portion 2, it is possible to reduce the risk of deterioration from the interface between the base portion 1 and the filter portion 2.

In particular, since the base portion 1 and the filter portion 2 are made of the same ceramic, the thermal expansion coefficients of the base portion 1 and the filter portion 2 can be made close to each other. As a result, the long-term reliability of the particulate matter measuring device component 100 under the heat cycle can be improved. As used herein, "consisting of the same ceramics" means that the main components (components occupying 80% by mass or more) of the ceramics forming the base portion 1 and the filter portion 2 are the same.

In the particulate matter measuring device component 100 of the present disclosure, the base portion 1 and the filter portion 2 are made of alumina. Alumina can be manufactured at low cost, and in addition, the porosity of the surface can be easily adjusted as shown below.

The base portion 1 having a surface having a porosity of 3% or less and the filter portion 2 having a surface having a porosity of about 40 to 70% can be integrally formed by the following method, for example. Specifically, a ceramic paste containing 93% by mass of alumina powder and 7% by mass of a resin binder is used for the portion to be the base 1. For the portion that becomes the filter portion 2, a ceramic paste containing 55% by mass of alumina powder, 38% by mass of a pore-forming material, and 7% by mass of a resin binder is used. These ceramic pastes are processed into a green sheet having a predetermined shape by using a doctor blade method. At this time, by printing a conductive paste on the green sheet, the electrode 3 for forming the capacitance can be formed. Then, these green sheets are pressure-laminated using a uniaxial press. The surface of the filter part 2 and the base part 1 having the above-mentioned porosity can be formed by baking the surface after processing the surface if necessary.

The dimensions of the filter portion 2 are, for example, equal to the length of the base portion 1 in the width direction of 0.3 mm and the length of the base portion 1 in the thickness direction equal to the distance between the bottom surface and the ceiling surface of the flow passage 11. The length along the length direction of the base 1 can be set to 0.2 mm and 40 mm.

The electrode 3 is a member for forming capacitance. As shown in FIG. 3, the electrodes 3 are provided in pairs on the base 1 so as to sandwich the filter unit 2. More specifically, when a plurality of flow channels 11 are provided as in the particulate matter measuring device component 100 of the present disclosure, the filter units 2 located in the respective flow channels 11 should be sandwiched. An electrode 3 is provided. The electrode 3 may be provided, for example, so as to cover the plurality of filter units 2 or may be provided so as to correspond to each of the filter units 2. Then, as shown in FIG. 3, in the case where two channels 11 are provided in the vertical direction as in the particulate matter measuring device component 100 of the present disclosure, the electrode 3 has the upper channel 11 Above, between the upper flow path 11 and the lower flow path 11, and below the lower flow path 11. The electrode 3 positioned between the upper flow path 11 and the lower flow path 11 can form a capacitance with the upper electrode 3 of the upper flow path 11, and Capacitance can be formed between the lower electrode 11 and the lower electrode 3 as well.

An electrostatic capacitance is formed between the pair of electrodes 3 that sandwich the filter unit 2. When the particulate matter is collected by the filter unit 2, the capacitance between the pair of electrodes 3 changes. By detecting this change in capacitance with an external detection device, it is possible to measure the deposition amount of the particulate matter trapped in the filter unit 2.

In the particulate matter measuring device component 100 of the present disclosure, the electrode 3 is embedded in the base 1. As a result, it is possible to reduce the risk that the electrode 3 will be affected by gas corrosion and the like. Further, since it is possible to reduce the possibility that the particulate matter or the like adheres to the surface of the electrode 3, it is possible to improve the measurement accuracy of the particulate matter measuring device component 100. In the particulate matter measuring device component 100 of the present disclosure, the electrode 3 is provided (embedded) inside the base portion 1, but the present invention is not limited to this. Specifically, the position at which the electrode 3 is provided may be, for example, the outer surface of the base 1 (the surface other than the wall surface of the flow channel 11).

As shown in FIG. 8, in the particulate matter measuring device component 100 of the present disclosure, the electrode 3 has, for example, a linear wiring pattern and is provided along the filter unit 2. As described above, since the electrode 3 is provided along the filter unit 2, the linearity between the amount of the particulate matter collected by the filter unit 2 and the change in the capacitance between the electrodes 3 is improved. be able to. This is because, since the electrode 3 is provided along the filter portion 2, it is possible to reduce the change in the capacitance due to the particulate matter attached to the portion other than the filter portion 2 (for example, the wall surface of the flow channel 11). Is. The shape of the electrode 3 in plan view is not limited to a linear shape, and may be, for example, a circular shape or a rectangular shape.

Further, by forming the electrode 3 into a linear wiring pattern, the resistance value can be increased as compared with the case where the electrode 3 is circular or rectangular. Therefore, a high voltage can be applied to the electrode 3 to function as a heater. Thereby, the particulate matter collected in the filter unit 2 can be removed by heating.

In particular, as in the example shown in FIG. 9, the electrode 3 has a linear wiring pattern and is provided in a region of the base 1 that sandwiches the filter unit 2 and a region that does not sandwich the filter unit 2. At times, a portion of the electrode 3 located in a region not sandwiching the filter portion 2 may be narrower in width than a portion located in a region sandwiching the filter portion 2. Accordingly, the width of the portion of the electrode 3 located in the region sandwiching the filter portion 2 is secured, and the capacitance between the electrodes 3 is favorably formed, while the electrode 3 is located in the region where the filter portion 2 is not sandwiched. The resistance value can be increased by narrowing the width of the portion to be etched. As a result, it is possible to effectively function as the heater while effectively functioning as the electrode 3 for capacitance formation.

In the example shown in FIG. 8 and FIG. 9, the end portion of the electrode 3 has a lead-out portion 3 a drawn to the base portion 1 located outside the flow path 11 in the width direction (x-axis direction) of the base portion 1. There is. The lead-out portion 3a is further pulled out to the outer surface of the base portion 1 and electrically connected to an external device. For example, a penetrating conductor (not shown) that is electrically connected by the lead portion 3 a and penetrates the base portion 1 and is drawn to the upper surface of the base portion 1 is provided. A terminal electrode (not shown) is provided on the upper surface of the base 1, and a through conductor is electrically connected. This terminal electrode can be electrically connected to an external detection device.

In the example shown in FIG. 8 and FIG. 9, each of the pair of electrodes 3 sandwiching the filter portion 2 has a meandering shape that meanders by connecting the ends of the portions provided along each of the plurality of filter portions 2. Is one linear wiring pattern. The end of the one electrode is led out to the outer surface of the base 1, and each of the pair of electrodes 3 is a single-system wiring. On the other hand, in the example shown in FIGS. 10 and 11, each of the pair of electrodes 3 is formed of two meander-shaped linear wiring patterns and has two lines of wiring. In the example shown in FIG. 10, the two wiring patterns are arranged side by side in the width direction (x-axis direction) of the channel 11, and in the example shown in FIG. 11, the two wiring patterns are arranged in the length direction of the channel 11. They are arranged side by side in the (y-axis direction).

In this way, when each of the pair of electrodes 3 arranged so as to sandwich the filter portion 2 is a two-system wiring, while the particulate matter is detected by the electrode 3 of one system, the other system of the other system is detected. The particulate matter collected by the electrode 3 can be removed. Therefore, it is possible to continuously detect the particulate matter without stopping the detection of the particulate matter for removing the particulate matter. In the example shown in FIG. 10 and FIG. 11, each of the pair of electrodes 3 arranged so as to sandwich the filter unit 2 has two lines of wiring, but since it may be a plurality of lines, three or more lines are required. It may be wiring.

As the electrode 3, for example, a metal material such as platinum or tungsten can be used. When the electrode 3 has a linear wiring pattern, the width can be set to 2 mm, the length can be set to 38 mm, and the thickness can be set to 30 μm.

In the above-disclosed particulate matter measuring device component 100, the base 1 has a shape having the flow passage 11 therein, but is not limited thereto. Specifically, for example, as shown in FIG. 12, a pair of bases 1 that are plate-shaped members made of ceramics and are juxtaposed so that their main surfaces face each other, and a flow path space between the pair of bases 1. A filter part 2 made of porous ceramics that is provided so as to divide 10 to form a flow path 11, and a capacitance forming part that is provided on each of a pair of base parts 1 and that sandwiches the filter part 2. May be provided with a pair of electrodes 3. Then, as shown in FIGS. 2, 4 to 7, the filter unit 2 may include the filter unit 2 arranged to be inclined with respect to the length direction of the flow channel space 10.

In another particulate matter measuring device component 100, a flow passage 11 is formed by partitioning a flow passage space 10 between the base 1 and the base 1 with a filter portion 2. It is possible to measure the amount of the particulate matter by detecting the change in the capacitance between the electrodes 3 while collecting the particulate matter by the filter unit 2 by flowing the gas through the flow path 11. In such a particulate matter measuring device component 100, the measurement accuracy can be improved as in the case of the particulate matter measuring device component 100 described above.

More specifically, in the particulate matter measuring device component 100 shown in FIG. 12, three bases 1 are provided side by side with two flow channel spaces 10 provided therebetween. There are provided seven filter units 2 each. The number of the base portions 1 may be two or three or more, and the number of the filter portions 2 can be appropriately changed.

In the particulate matter measuring device component 100 shown in FIG. 12, the filter portion 2 also serves as a side wall, but the base portion 1 in contact with the filter portion 2 may be provided as a side wall outside the outer filter portion 2. This is the same as that of the particulate matter measuring device component 100 shown in FIG. 3, in which the outer filter portion 2 is arranged so as to be in contact with the side wall of the base portion 1. By doing so, the rigidity of the particulate matter measuring device component 100 can be improved, and the exposed area of the filter portion 2 having a relatively low strength can be reduced, so that deformation due to thermal stress or external force can occur. The damage can be suppressed and the reliability is high. In addition, all the wall surfaces facing the flow path 11 become the filter section 2, so that the collection efficiency is higher and the sensitivity is higher.

The particulate matter measuring device component 100 shown in FIGS. 13 to 15 has a plurality of filters 2 having different degrees of porosity. Such as the part 100 for measuring a particulate matter that can know the particle size distribution of the particulate matter, or the part 100 for measuring a particulate matter that can collect the particulate matter continuously for a long time and has a long life. , And can have higher added value.

Specifically, in the example shown in FIG. 13, the filter portion 2 made of porous ceramics has three types of filter portions 2a, 2b, 2c having different pore sizes and pore diameters. The example shown in FIG. 13 has a first filter portion 2a having a relatively large pore diameter, a third filter portion 2c having a small pore diameter, and a second filter portion 2b having a pore diameter intermediate between these. ing.

Since the plurality of filter portions 2a, 2b, 2c having different pore diameters are provided, the particulate matter collected by the respective filter portions 2a, 2b, 2c have different average particle diameters from each other. .. Therefore, the particle size distribution of the collected particulate matter can be known from the electrostatic capacitance detected by the electrodes 3 sandwiching each of the plurality of filter portions 2a, 2b, 2c having different pore diameters. It is possible to estimate the combustion state in the engine that discharges the gas and the state of the PM filter located upstream of the particulate matter measuring device component 100.

Further, in the example shown in FIG. 13, the plurality of filter portions 2a, 2b, 2c having different pore diameters are arranged in the order of the pore diameters. Specifically, in the example shown in FIG. 13, three flow passage spaces 10 (flow passages 11) are arranged in the vertical direction (z-axis direction) of the drawing, and the first filter portion 2a is provided in the upper stage. The second filter unit 2b is disposed in the middle stage, and the third filter unit 2c is disposed in the lower stage. That is, the filter portions 2 having the same pore diameter in each stage are arranged in a line in the left-right direction of the drawing (width direction of the flow path space 10 and the base portion 1, x-axis direction). By arranging in this way, the electrodes 3 sandwiching the filter portion 2 having the same pore diameter can be arranged side by side, and these can be integrated into one as in the example shown in FIG.

The number of types of pore size of the filter portion 2 is not limited to three, and may be two or four or more. Further, in the example shown in FIG. 13, the filter portions 2 having the same pore diameter are arranged in a row in the width direction (x-axis direction) of the base portion 1, but in the arrangement direction of the plurality of base portions 1 (z-axis direction). You may arrange in a line. Alternatively, they may be arranged randomly, but they may be arranged in a line as described above.

The pore diameter referred to here is the average pore diameter. The pore diameter may be obtained by taking an SEM image of the surface or cross section of the filter unit 2 and calculating the average pore diameter of the pores within the range of this SEM image by image analysis. The SEM magnification is 100 times, and the SEM image with a visual field of 1.0 mm×1.3 mm may be used.

If the filter portion 2 has a pore diameter of 1 μm to 60 μm, and the filter portion 2 has three types of filter portions 2a, 2b, 2c having different pore diameters as in the above example, for example, the first filter is used. The pore diameter of the portion 2a may be 10 μm to 60 μm, the pore diameter of the second filter portion 2b may be 5 μm to 30 μm, and the pore diameter of the third filter portion 2c may be 1 μm to 15 μm.

Further, in the example shown in FIGS. 14 and 15, the filter portion 2 made of porous ceramics has two types of filter portions 2d and 2e having different porosities. The examples shown in FIGS. 14 and 15 have a fourth filter portion 2d having a relatively large porosity and a fifth filter portion 2e having a small porosity. Then, in a cross-sectional view perpendicular to the longitudinal direction of the flow path space 10, the porosity of the filter portion 2 located outside is larger than the porosity of the filter portion 2 located inside. It should be noted that the term “located outside” as used herein may be the outside in the vertical direction as shown in FIG. Further, “located outside” may mean outside in the width direction of the flow path space 10, as shown in FIG. In addition, “located outside” may mean the outside in the entire vertical and width directions.

In a cross-sectional view perpendicular to the length direction of the flow path space 10, the fourth filter portion 2d is arranged on the outer side and the fifth filter portion 2e is arranged on the inner side. In the example shown in FIG. 14, the fourth filter portion 2d is arranged on the outer side in the vertical direction of the drawing (the arrangement direction of the plurality of base portions 1, the z-axis direction), and the fifth filter portion 2e is arranged on the inner side. There is. Three flow passage spaces 10 are arranged in the vertical direction (arrangement direction of a plurality of bases 1, z-axis direction) in the drawing, and a fourth filter portion 2d is arranged in the upper and lower flow passage spaces 10. The fifth filter portion 2e is arranged in the flow space 10 in the middle stage. In the example shown in FIG. 15, the fourth filter portion 2d is arranged on the outer side in the left-right direction of the drawing (the width direction of the flow path space 10 and the base portion 1, the x-axis direction), and the fifth filter portion 2e is arranged on the inner side. It is arranged. Three stages of flow passage spaces 10 are arranged in the up-down direction (arrangement direction of the plurality of bases 1, z-axis direction), and the flow passage spaces 10 each have a left-right direction (width direction of the flow passage space 10 and the base 1, Six filter units 2 are arranged in the x-axis direction). Of the six filter parts 2, two on the left and right are the fourth filter parts 2d, and the two located between them are the fifth filter parts 2e.

When the gas containing the particulate matter flows through the flow path space 10 (flow path 11) in the particulate matter measuring device component 100, the central portion of the flow path space 10 (in the longitudinal direction of the flow path space 10) The flow rate of the gas flowing in the inner area in the vertical sectional view) is larger than the flow rate of the gas flowing in the outer peripheral portion of the flow channel space 10 (the outer area in the vertical sectional view of the flow channel space 10). Tend. Therefore, the inner filter portion 2 collects more particulate matter than the outer filter portion 2, and the clogging of the particulate matter also becomes faster. If the clogging of the particulate matter is early, the frequency of performing the regeneration for removing the particulate matter by heating with the heater is increased, so that the deterioration of the particulate matter measuring device component 100 is accelerated. On the other hand, as described above, in the cross-sectional view perpendicular to the length direction of the flow path, the porosity of the filter portion 2 located outside (the fourth filter portion 2d) is the filter portion 2 located inside. When the porosity is higher than that of the (fifth filter portion 2e), the gas is more likely to flow toward the filter portion 2 (fourth filter portion 2d) having a higher porosity, and the gas is more likely to flow in the cross section perpendicular to the length direction of the flow path. , The gas flow rate difference depending on the position becomes small. Therefore, only the inner filter portion 2 is not clogged with the particulate matter quickly, so that the particulate matter can be continuously collected for a long time and the long-life particulate matter measuring device component 100 can be used. Become.

In FIG. 14 and FIG. 15, the porosity of the filter portion 2 (fourth filter portion 2d) located outside in the vertical direction and outside in the horizontal direction is equal to that of the filter portion 2 located inside (the fifth filter portion). 2e) is larger than the porosity, but the porosity of the filter portion 2 which is a combination of these and is located outside in the vertical and horizontal directions, and on the outer peripheral portion in the cross section is inward in the vertical and horizontal directions and at the central portion in the cross section. It may be larger than the porosity of the filter part 2 located. If the base portion 1 and the filter portion 2 are arranged alternately in the vertical direction, the fourth filter portion 2d is arranged on the outer side in the vertical direction and the fifth portion is arranged on the inner side as in the example shown in FIG. The structure in which the filter part 2e is disposed can be easily manufactured by a manufacturing method described later.

Examples of the porosity measuring method for comparing the porosities of the filter portions 2 include a mercury porosimetry method (JIS standard R1655:2003) and image analysis of SEM images. The image analysis of the SEM image can be performed by photographing the SEM image of the cross section of the filter unit 2 and calculating the area ratio of the pores within the range of the SEM image by image analysis. For example, the SEM magnification is 100 times, and the SEM image with a visual field of 1.0 mm×1.3 mm may be used.

When the porosity of the filter part 2 is 40 to 70%, the porosities of the filter part 2d having a relatively large porosity and the filter part 2e having a relatively small porosity are 50 to 70% and 40 to 60%, respectively. %And it is sufficient.

In the above-described particulate matter measuring device component 100, the flow path 11 has been described as an example extending from one side surface of the base 1 to the side surface at a position opposite to the side surface, but the flow path 11 is not limited to this. .. For example, as in the example shown in FIG. 16, the flow path space 10 has one end opened to one side surface of the base 1 and the other end opened to a surface (lower surface) located at one end of the base 1. Good. In the example shown in FIG. 16, the inflow port 4 is provided on the upper surface of the base portion 1, and the flow passage 11 is divided into two stages of flow passages 11 inside the base portion 1 and the side surface of the base portion 1 (the lower side surface in the drawing). ) Extends to the outflow port 5 provided in the. The filter part 2 is provided in each flow path 11 and is divided into a first flow path 11a and a second flow path 11b. The flow of gas is shown by an outline arrow, and the gas flows in through an inflow port 4 provided on the upper surface of the base 1 and flows out through an outflow port 5 provided on the side surface of the base 1. Alternatively, the openings may be formed in two opposing side surfaces of the base 1 and a surface (lower surface) located at one end of the base 1.

As described above, the method for manufacturing the particulate matter measuring device component 100 in which the dense base portion 1 made of ceramics and the filter portion 2 made of porous ceramics are integrally formed is, for example, a plurality of first Of the ceramic green sheets 12, the step of preparing the plurality of second ceramic green sheets 22, the step of forming the electrode layers 32 on the first ceramic green sheets 12, and the second ceramic green sheets 22. A step of forming a through hole 112 in the substrate, and a step of forming a laminated body 102 by laminating the first ceramic green sheet 12 in which the electrode layer 32 is formed and the second ceramic green sheet 22 in which the through hole 112 is formed. And a step of firing the laminated body 102.

According to such a manufacturing method, the above-described particulate matter measuring device component 100 in which the dense base portion 1 made of ceramics and the filter portion 2 made of porous ceramics are integrally formed is manufactured. can do.

FIG. 17 is a schematic view showing, for each step, a method for manufacturing a component for a particulate matter measuring device. FIG. 17 shows a process of manufacturing the particulate matter measuring device component 100 such as the example shown in FIG. 12 in which the number of the filter portions 2 arranged between the pair of base portions 1 is changed from seven to six. It is shown. First, as in the example shown in FIG. 17A, a plurality of first ceramic green sheets 12 and a plurality of second ceramic green sheets 22 are prepared. The first ceramic green sheet 12 is a portion that will be sintered to become the base portion 1 in a subsequent firing step, and the second ceramic green sheet 22 will be a portion that will similarly become the filter portion 2. The filter portion 2 is made of porous ceramics, while the base portion 1 is made of dense ceramics. Therefore, the second ceramic green sheet 22 has more pores (increased porosity) than the first ceramic green sheet 12 when sintered in the subsequent firing step. Specifically, the second ceramic green sheet 22 contains more components that become pores when sintered in the firing process, as compared with the first ceramic green sheet 12. Specifically, those containing a large amount of organic binder components, those containing a pore former, and the like. Alternatively, the amount of the sintering aid component is small in order to reduce the sinterability and increase the pores.

It is preferable to use a pore-forming material because it is easy to adjust the pore diameter and porosity. The pore-forming material is in the form of particles that will be burned out in the subsequent firing step. Examples of the pore-forming material include acrylic resin beads (methacrylic acid ester-based copolymer), carbon powder, and crystalline cellulose. The particle size of the pore-forming material may be 1 to 1.2 times the pore diameter of the filter part 2. In the case of producing the filter part 2 having a pore diameter of 1 μm to 60 μm as described above, a pore former having an average particle diameter of 1 μm to 72 μm may be used. The porosity can be adjusted by the particle size and amount of the pore-forming material.

In the case where the base 1 is made of alumina ceramics, the first ceramic green sheet 12 firstly contains alumina powder and a sintering aid (powder such as SiO ₂ , MgO, CaO) as an organic binder such as an acrylic resin. An organic solvent such as toluene or acetone or a solvent such as water is mixed to prepare a slurry. The slurry may be used to form a sheet by a film forming method such as a doctor blade method. The second ceramic green sheet 22 may be prepared by adding a pore-forming material to the slurry for the first ceramic green sheet 12. The second ceramic green sheet 22 includes a pore forming material with respect to the first ceramic green sheet 12.

When the filter portion 2 has different pore diameters, for example, as the pore-forming materials added to the slurry for the second ceramic green sheet 22, those having different average particle diameters are used. A plurality of types of second ceramic green sheets 22 having different average particle sizes may be produced. When the filter portion 2 has different porosities, for example, the amount of the pore-forming material added to the slurry for the second ceramic green sheet 22 is made different from each other, and the average particle diameter of the pore-forming material included is different. A plurality of types of second ceramic green sheets 22 may be produced.

Next, as in the example shown in FIG. 17B, the electrode layer 32 is formed on the first ceramic green sheet 12. The electrode layer 32 is sintered to form the electrode 3 in the subsequent firing step. The electrode layer 32 may be formed by applying a metal paste containing a metal material such as platinum or tungsten, which is the main component of the electrode 3, as the main component on the first ceramic green sheet 12. The metal paste can be prepared by adding a resin binder and a solvent to powder of a metal material and kneading. The metal paste may be applied to the wiring pattern shape of the electrode 3 by a screen printing method or the like. At this time, the electrode layer 32 is formed on only one side of the surface of the first ceramic green sheet 12.

Further, as in the example shown in FIG. 17C, the through hole 112 is formed in the second ceramic green sheet 22. The through hole 112 is a portion that becomes the flow path 11. The through holes 112 may be formed in the second ceramic green sheet 22 by punching using a mold or laser processing.

Next, as in the example shown in FIG. 17D, the first ceramic green sheet 12 having the electrode layer 32 formed thereon and the second ceramic green sheet 22 having the through holes 112 formed therein are laminated to form a laminated body. 102 is formed. In the example shown in FIG. 17D, three base portions 1 are each formed by laminating two layers of the first ceramic green sheets 12, and a portion serving as the filter portion 2 is the two layers of the second ceramic. The green sheets 22 are stacked and formed. In either case, one layer or three or more layers of ceramic green sheets may be used.

The example shown in FIG. 17D is a laminated body 102 in the case of manufacturing the component 100 for a measuring device for particulate matter in which the electrode 3 as in the example shown in FIG. The numeral 32 is located between the layers of the two-layer first ceramic green sheet 12. The first ceramic green sheet 12 on which the electrode layer 32 is not formed is laminated on the first ceramic green sheet 12 on which the electrode layer 32 is formed.

In the case of manufacturing the particulate matter measuring device component 100 as in the example shown in FIG. 3, the first ceramic green sheet 12 on which the electrode layer 32 is formed does not have the electrode layer 32 formed thereon. By stacking only the portion of the second ceramic green sheet 22 which will be the filter portion 2 on top of the above ceramic green sheet 12, and by further stacking the frame-shaped first ceramic green sheet 12 so as to surround it. Good.

In order to form the laminated body 102, the first ceramic green sheet 12 having the electrode layer 32 formed thereon and the second ceramic green sheet 22 having the through hole 112 formed thereon are stacked and pressed by a uniaxial pressure press or the like. It may be integrated by pressing and crimping.

By filling the through hole 112 with a resin or the like that will be burned out in the subsequent firing step, it is possible to suppress the deformation of the portions of the first ceramic green sheet 12 located above and below the through hole.

Then, by firing the laminated body 102, the particulate matter measuring device component 100 in which the dense base portion 1 made of ceramics and the filter portion 2 made of porous ceramics are integrally formed as described above. Becomes If the base portion 1 and the filter portion 2 are made of alumina ceramics, the firing temperature may be set to 1500°C to 1600°C.

In order to form the through conductor, a through hole is formed in a necessary ceramic green sheet by punching using a mold or laser processing before the step of manufacturing the laminated body 102, and the electrode layer 32 is formed in this through hole. It suffices to fill the same conductive paste as that used for forming.

1: Base 10: Flow path space 11: Flow path 11a: First flow path 11b: Second flow path 2: Filter part 3: Electrode 4: Inlet port 5: Outlet port 100: For particulate matter measuring device parts

Claims (9)

A base portion made of ceramics and having a flow passage space through which a gas flows; a filter portion made of porous ceramics provided in the flow passage space so as to form a flow passage by dividing the flow passage space into a plurality of portions; In a region facing each other across the flow path space of the base portion, while having a meander-shaped linear wiring pattern meandering by connecting the end portions of the portion provided along each of the plurality of filter portions, A pair of electrodes for capacitance formation provided so as to sandwich the filter portion along the filter portion,
The filter part is a part for a measuring device for particulate matter, including a part arranged to be inclined with respect to a length direction of the flow path space. A pair of bases, which are plate-shaped members made of ceramics and are arranged side by side so that their main surfaces are opposed to each other, and are provided so as to form a flow path by dividing a flow path space through which gas flows between the bases. And a pair of bases each having a meander-shaped linear wiring pattern meandering by connecting end portions of portions provided along each of the plurality of filter portions to the pair of bases. Together with a pair of electrodes for capacitance formation provided along the filter portion so as to sandwich the filter portion,
The filter part is a part for a measuring device for particulate matter, including a part arranged to be inclined with respect to a length direction of the flow path space. The flow channel has a first flow channel connected to an inflow port through which the gas flows in, and a second flow channel connected to an outflow port through which the gas flows out, and the first flow channel is the above-mentioned The particle according to claim 1 or 2, wherein the width decreases from the inflow port in the length direction and the width of the second flow path increases in the length direction to the outflow port. Parts for measuring devices for particulate matter. The component for a particulate matter measuring device according to any one of claims 1 to 3, wherein the electrode is embedded in the base portion. The particulate matter measuring device component according to any one of claims 1 to 4, wherein the base portion and the filter portion are integrally formed. The component for a particulate matter measuring device according to any one of claims 1 to 5, wherein the base portion and the filter portion are made of the same ceramics. The particulate matter measuring device component according to claim 6, wherein the base portion and the filter portion are made of alumina. The particulate matter measuring device component according to any one of claims 1 to 7, comprising a plurality of the filter portions having mutually different pore diameters. The cross-sectional view perpendicular to the lengthwise direction of the flow path space has a porosity of the filter portion located outside is larger than a porosity of the filter portion located inside. Part for measuring device for particulate matter described.

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