JP2006097476A - Exhaust gas purifying filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas purifying filter having no possibility of crack caused by thermal stress, occurrence of failure and occurrence of plugging in an exhaust gas channel, with excellent temperature rise of a catalyst. <P>SOLUTION: A packed casing 2a arranged in an exhaust pipe 10 is provided in which both the end openings of a cylindrical peripheral wall 20a are covered with a front wall 21a and a rear wall 22a so as to form its inside as a permeable storage chamber 3. An antenna 15 radiating microwave from a microwave oscillator 13 is inserted into the center of the permeable storage chamber 3 along a longitudinal direction. Metal oxide fine particles whose temperatures are raised by microwave are filled into the permeable storage chamber 3. Inflow holes 30a communicated with the upstream side of the exhaust pipe 10, and exhaust holes 31a, 31b discharging exhaust gas led to flow between the metal oxide fine particles to the downstream side of the exhaust pipe 10, are formed in a wall part partitioning the permeable storage chamber 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust gas purification filter that purifies exhaust gas from an internal combustion engine or the like of an automobile by catalytic action of a metal oxide that is enclosed in an exhaust pipe and heated by microwaves.

  Exhaust gases from internal combustion engines of automobiles contain harmful substances such as hydrocarbons, carbon monoxide, and nitrogen oxides. A processing method is used. This post-treatment method means that exhaust gas is passed through an exhaust gas purification means equipped with a catalyst, and the exhaust gas and catalyst are brought into contact with each other, thereby causing harmful substances in the exhaust gas such as hydrocarbons, carbon monoxide, and nitrogen oxides. A substance is oxidized or reduced and discharged into the atmosphere as harmless carbon dioxide, water vapor, nitrogen, or the like.

  Here, the catalyst used in this post-treatment method cannot exhibit its effective purification ability unless it is in a high temperature state of about 300 ° C. to 400 ° C. or higher. For this reason, when purifying the exhaust gas, it is necessary to first heat the catalyst to raise the temperature to a temperature at which the catalyst can exhibit the purification ability. The catalyst is generally heated by using the heat of the exhaust gas itself discharged from an internal combustion engine or the like and passing the high-temperature exhaust gas through the exhaust gas purification means.

  However, in such a method, immediately after the cold start of the internal combustion engine or the like, the temperature of the exhaust gas discharged is still in a low temperature state, so that the catalyst is not sufficiently heated and the exhaust gas is purified. I can't. Accordingly, the temperature of the exhaust gas discharged from the internal combustion engine or the like rises for a few minutes immediately after the cold start of the internal combustion engine or the like until the temperature of the catalyst rises to a temperature at which the catalyst can exhibit its effective exhaust gas purification capability. The exhaust gas containing a lot of harmful substances will be discharged into the atmosphere as it is.

  Therefore, in order to solve such a problem, exhaust gas purification filters described in Patent Documents 1 to 4 have been proposed. In such a structure, the exhaust gas purifying means carries a microwave absorber and a catalyst on the surface by dipping or drying, and has a myriad of ventilation communication passages formed by ceramic or metal partition walls. Or it consists of support | carriers, such as a porous structure similar to it. Simultaneously with the start of the internal combustion engine, microwaves are radiated to the exhaust gas purifying means, and the microwave absorber absorbs the microwaves, thereby raising the temperature of the microwave absorber and exhausting the same as the microwave absorber. The temperature of the catalyst supported on the surface of the gas purification means is increased by the heat from the heated microwave. As a result, the exhaust gas purification means raises the temperature to a temperature at which the catalyst can exhibit the purification capability in a short time, and effectively purifies the harmful substances contained in the exhaust gas even immediately after the cold start of the internal combustion engine. be able to.

  Further, in Patent Document 5, a metal oxide that absorbs microwaves and rises in temperature and has an excellent exhaust gas purifying ability itself is used as an exhaust gas purifying means that serves both as a microwave absorber and a catalyst. It has been proposed that the harmful substances contained in the exhaust gas immediately after the cold start of the internal combustion engine can be effectively reduced.

JP 2002-349229 A Japanese Patent Application Laid-Open No. 07-127436 Japanese Patent Laid-Open No. 05-340235 JP 05-68894 A JP 05-76727 A

  By the way, the microwave radiated from the antenna is not uniformly supplied to the entire area of the exhaust gas purification means, and the microwave is supplied well in the vicinity of the antenna, but in the area away from the antenna, the microwave is supplied. While the wave propagates to the region, it is absorbed by the microwave absorber or shielded by a carrier or the like, and the amount of microwave supply decreases. For this reason, each region of the exhaust gas purification means has a different temperature rise due to a difference in distance from the antenna, which causes a temperature difference. Here, since the conventional exhaust gas purifying means is composed of a carrier carrying a microwave absorber and a catalyst on the surface, the carrier carrying the microwave absorber rises as the temperature of the microwave absorber rises. It will warm up. For this reason, in the conventional exhaust gas purifying means, the microwave is radiated from the antenna, thereby causing a temperature difference between the parts of the carrier due to the difference in the temperature rise in each region. The amount of thermal expansion differs between the parts of the carrier, and cracks and breakage are likely to occur.

  Further, in the conventional exhaust gas purification means, the exhaust gas passes through a small ventilation communication passage such as the eyes of the honeycomb structure formed by the partition walls. The purifying means is likely to be clogged and needs to be maintained sufficiently. Furthermore, when exchanging, partial replacement is difficult, and it is necessary to replace all the exhaust gas purifying means itself, which is a problem in terms of cost and durability of use.

  Further, exhaust gases from automobile internal combustion engines and the like also contain harmful substances such as dioxins that need to be completely burned at a high temperature of about 600 ° C. to 700 ° C. or more for removal. In the gas purification means, since it takes time for the catalyst to rise to a high temperature state of about 600 ° C. to 700 ° C. or higher, such harmful substances are discharged immediately after the cold start of the internal combustion engine or the like. It has become.

  The present invention has been invented to solve the above-described problems, and there is no risk of cracking or breakage due to thermal stress or clogging of the exhaust gas flow path. The present invention proposes an exhaust gas purification filter capable of raising the temperature faster.

  The present invention relates to an exhaust gas purification filter that purifies exhaust gas from an internal combustion engine of an automobile or the like by catalytic action of a metal oxide that is enclosed in an exhaust pipe and heated by microwaves. Is covered with a front wall and a rear wall, and the inside is made into a breathable filling chamber. An antenna that radiates microwaves from the oscillator is inserted, and the air-permeable filling chamber is filled with metal oxide particles that are heated by the microwave, and the wall that defines the air-permeable filling chamber is upstream of the exhaust pipe. An exhaust gas purification filter comprising an inflow hole communicating with the side and an exhaust hole for discharging exhaust gas flowing between the metal oxide particles to the downstream side of the exhaust pipe (Claim 1) It is.

  In the present invention, a metal oxide that absorbs microwaves and raises the temperature and has an excellent exhaust gas purifying ability itself is used as a combination of the microwave absorber and the catalyst. Further, the metal oxide is in the form of particles having a large surface area so as to make good contact with the exhaust gas passing through the air-permeable filling chamber. The metal oxide particles are filled in a breathable filling chamber defined by the cylindrical outer peripheral wall, the front wall, and the rear wall of the filled casing, and the metal oxide particles are individually independent. Some floating can be achieved by contact with exhaust gas.

  In the center of the air-permeable filling chamber, an antenna that radiates microwaves from the microwave oscillator is inserted along the longitudinal direction from the front wall to the rear wall of the filling housing. Such an antenna radiates microwaves radially in the radial direction toward the metal oxide particles in the air-permeable filling chamber. The microwaves radiated from the antenna are gradually absorbed by the metal oxide particles as they travel radially in the air-permeable filling chamber, so the microwaves supplied to the metal oxide particles are the largest in the vicinity of the antenna. It is the smallest in the vicinity of the cylindrical outer peripheral wall of the filling housing. That is, the metal oxide particles are most likely to have a high temperature in the vicinity of the antenna, and are most difficult to increase in the vicinity of the outer peripheral wall of the filled casing. Therefore, by inserting the antenna into the center of the air-permeable filling chamber, the distance between the vicinity of the outer peripheral wall of the filling housing that is difficult to be heated to the highest temperature and the antenna becomes the shortest, and the entire area of the air-permeable filling chamber is heated faster. It will be.

  Among the walls that define the air-permeable filling chamber, the exhaust gas from the internal combustion engine or the like is air-permeable to the wall portion (specifically, the front wall) that separates the upstream side of the exhaust pipe and the air-permeable filling chamber. In order to flow into the filling chamber, an inflow hole that connects the upstream side of the exhaust pipe and the air-permeable filling chamber is formed. Further, in order to discharge exhaust gas purified by flowing between the metal oxide particles in the air-permeable filling chamber to the downstream side of the exhaust pipe, a wall portion separating the air-permeable filling chamber and the downstream side of the exhaust pipe ( Specifically, an exhaust hole that communicates the air-permeable filling chamber and the downstream side of the exhaust pipe is formed in the rear wall). The inflow hole and the exhaust hole have a hole diameter smaller than the particle diameter of the smallest metal oxide particle to be filled so as to prevent the metal oxide particles from leaking out from the breathable filling chamber, and define the breathable filling chamber. An infinite number of walls are formed with a predetermined aperture ratio.

  In such a configuration, the metal oxide particles filled in the breathable filling chamber absorb the microwaves by the microwave radiated from the antenna inserted in the center of the breathable filling chamber inside the filling casing. The temperature is raised to a temperature at which the purification ability can be demonstrated in a short time. Exhaust gas discharged from an internal combustion engine or the like flows into the air permeable filling chamber through an inflow hole formed in a wall portion defining the air permeable filling chamber. Then, the metal oxide particles are purified in contact with the metal oxide particles in the air-permeable filling chamber, and are discharged from the air-permeable filling chamber through the exhaust holes formed in the other wall portions of the air-permeable filling chamber.

  The present invention also relates to an exhaust gas purification filter that purifies exhaust gas from an internal combustion engine of an automobile or the like by catalytic action of a metal oxide that is enclosed in an exhaust pipe and heated by microwaves. And a plurality of unit air-permeable filling chambers that are partitioned by a partition wall in the circumferential direction and by a front wall portion and a rear wall portion in the longitudinal direction, and are arranged in the exhaust pipe. An antenna that radiates microwaves from a microwave oscillator is inserted along the longitudinal direction in the center of each case, and metal oxide particles that are heated by microwaves are inserted into each unit air-permeable filling chamber. The wall portion that is filled and further defines each unit air-permeable filling chamber has an inflow hole that communicates with the upstream side of the exhaust pipe, and an exhaust that exhausts exhaust gas that has circulated between the metal oxide particles to the downstream side of the exhaust pipe Each hole is formed It is an exhaust gas purification filter according to claim (Claim 2) comprising been.

  In such a configuration, a metal oxide that absorbs microwaves and rises in temperature and has an exhaust gas purification ability that is excellent in itself is used in the form of particles having a large surface area, and in the radial direction, an outer wall portion and an inner wall portion Thus, the unit air-permeable filling chamber partitioned by the partition wall in the circumferential direction and the front wall portion and the rear wall portion in the longitudinal direction is filled. Since the filled metal oxide particles are independent of each other, they can be slightly moved by contact with the exhaust gas. In addition, since the filling region filled with the metal oxide particles is divided into a plurality of unit air-permeable filling chambers, the filling region caused by the difference in the particle size and mass of the metal oxide particles, vibration from the internal combustion engine, etc. The degree of uneven distribution of the metal oxide particles inside is reduced.

  In the center of the filling housing, a plurality of unit breathable filling chambers are connected in the circumferential direction so that the inner wall portions of the unit breathable filling chambers are coupled and the antenna is inserted inside. A cylindrical antenna peripheral wall serving as a hole is formed. Further, when the partition walls of each unit breathable filling chamber are in contact with each other in the circumferential direction, the outer wall portion of each unit breathable filling chamber is coupled to the outer peripheral edge of the filling housing, When the partition walls of the unit breathable filling chambers are not in contact with each other, the outer wall portion and the partition wall of each unit breathable filling chamber are coupled to form the outer peripheral wall of the filling casing. Further, a front wall portion and a rear wall portion that cover both longitudinal opening of each unit air-permeable filling chamber are coupled to both ends in the longitudinal direction of the filling housing, and the front wall and the rear wall of the filling housing are coupled. Are formed respectively. Here, each of the wall portions of the filling casing has, for example, each unit ventilation such that the front wall and the rear wall collectively cover both end openings in the longitudinal direction of all unit breathable filling chambers. It is also possible to integrally form and provide a wall portion that defines the functional filling chamber.

  In the antenna insertion hole inside the antenna peripheral wall, an antenna that radiates microwaves from the microwave oscillator along the longitudinal direction from the front wall to the rear wall of the filling housing is located at the center of the filling housing. It is inserted. Such an antenna radiates microwaves radially in the radial direction toward the metal oxide particles in each unit air-permeable filling chamber. The microwaves radiated from the antenna are gradually absorbed by the metal oxide particles as they travel in the radial direction in each unit air-permeable filling chamber, so the microwaves supplied to the metal oxide particles are the most in the vicinity of the antenna. It increases and becomes the smallest near the outer peripheral wall of the filled casing. That is, the metal oxide particles are most likely to have a high temperature in the vicinity of the antenna, and are most difficult to increase in the vicinity of the outer peripheral wall of the filled casing. Therefore, by inserting the antenna through the center of the filling case, the distance between the vicinity of the outer peripheral wall of the filling case where the temperature is hardly increased and the antenna becomes the shortest, and the entire area of each unit air-permeable filling room is heated faster. Will be.

  Of the wall portions defining each unit breathable filling chamber, the wall portion (specifically, the front wall portion) separating the upstream side of the exhaust pipe and each unit breathable filling chamber is supplied from an internal combustion engine or the like. In order to allow the exhaust gas to flow into each unit breathable filling chamber, an inflow hole that communicates the upstream side of the exhaust pipe and each unit breathable filling chamber is formed. Further, in order to exhaust the exhaust gas purified by flowing between the metal oxide particles in each unit breathable filling chamber to the downstream side of the exhaust pipe, each unit breathable filling chamber is separated from the downstream side of the exhaust pipe. The wall portion (specifically, the rear wall portion) is formed with an exhaust hole that communicates each unit breathable filling chamber with the downstream side of the exhaust pipe. The inflow hole and the exhaust hole have a hole diameter smaller than the particle diameter of the minimum metal oxide particles to be filled so that the metal oxide particles do not leak from each unit breathable filling chamber. An infinite number of openings are formed on the walls that define the chamber.

  In such a configuration, each unit breathable filling chamber is filled with microwaves radiated from an antenna inserted in the center of a filling casing formed by connecting a plurality of unit breathable filling chambers in the circumferential direction. The metal oxide particles are heated to a temperature at which they can absorb microwaves and exhibit their purification ability in a short time. Exhaust gas discharged from an internal combustion engine or the like flows into each unit breathable filling chamber through an inflow hole formed in a wall portion that defines each unit breathable filling chamber. Then, it is purified by contacting with the metal oxide particles in each unit breathable filling chamber and discharged from each unit breathable filling chamber through the exhaust holes formed in the other wall portions.

  Here, in the exhaust gas purification filter, a cylindrical inner peripheral wall is disposed in the filling casing along the central longitudinal direction, and an antenna is inserted through the inner peripheral wall and communicated with the upstream side of the exhaust pipe. An exhaust passage that communicates with the downstream side of the exhaust pipe is formed between the outer surface of the filling housing and the inner surface of the exhaust pipe, and the inner peripheral wall of the filling housing communicates with the vent hole passage. A configuration (claim 3) is proposed in which the inflow hole is formed in the outer peripheral wall with an exhaust hole communicating with the exhaust path.

  In such a configuration, the filling casing is provided with a cylindrical inner peripheral wall having a vent hole path inside from the front wall to the rear wall along the central longitudinal direction. The front opening of the cylindrical inner peripheral wall is not shielded by the front wall of the filling housing, and the upstream side of the exhaust pipe communicates with the vent hole path. On the other hand, the rear opening of the cylindrical inner peripheral wall is shielded by the rear wall of the filling housing so that the exhaust gas flowing from the upstream side of the exhaust pipe into the vent hole path does not flow out to the downstream side of the exhaust pipe. Therefore, the front wall of the filling housing covers the annular front opening of the cylindrical outer peripheral wall and the cylindrical inner peripheral wall, and has an annular shape. Here, in the case where the filling housing is formed by connecting a plurality of unit breathable filling chambers in the circumferential direction, the cylindrical inner peripheral wall having a vent hole path on the inner side is formed by the inner wall portion of each unit breathable filling chamber. It is formed by coupling.

  Further, in such a configuration, a gap is defined between the outer surface of the filling housing housed in the exhaust pipe and the inner surface of the exhaust pipe, and the gap serves as an exhaust path. This exhaust path communicates only with the downstream side of the exhaust pipe, and a blocking wall is provided in front of the exhaust path so that exhaust gas does not flow directly from the upstream side of the exhaust pipe. This blocking wall is preferably formed integrally with the front wall of the filling housing.

  An antenna that radiates microwaves from the microwave oscillator along the longitudinal direction from the front wall to the rear wall of the filling housing at a position that becomes the center of the filling housing in the vent hole path inside the cylindrical inner peripheral wall Is inserted. Such an antenna radiates microwaves radially in the radial direction toward the metal oxide particles in the air-permeable filling chamber or each unit air-permeable filling chamber. The microwaves radiated from the antenna are gradually absorbed by the metal oxide particles as they travel radially in the air-permeable filling chamber or each unit air-permeable filling chamber. In the vicinity of the antenna, that is, in the vicinity of the cylindrical inner peripheral wall of the filling housing, the highest value is obtained, and in the vicinity of the cylindrical outer peripheral wall, the lowest value is obtained. Accordingly, the metal oxide particles in the air-permeable filling chamber or each unit air-permeable filling chamber are heated to the highest temperature in the vicinity of the inner peripheral wall, and exhibit their effective exhaust gas purification ability.

  In addition, an infinite number of inflow holes are formed in the cylindrical inner peripheral wall of the filling housing so as to communicate the vent hole path and the breathable filling chamber or each unit breathable filling chamber. Exhaust gas that has flowed into the vent hole path from the upstream side of the exhaust pipe flows in the radial direction from the vent hole path to the breathable filling chamber or each unit breathable filling chamber via the inflow hole. In addition, the cylindrical outer peripheral wall of the filling housing is formed with an infinite number of exhaust holes that connect the air-permeable filling chamber or each unit air-permeable filling chamber and the exhaust passage. The exhaust gas purified in contact with the metal oxide particles in the porous filling chamber flows out radially from the breathable filling chamber or each unit breathable filling chamber to the exhaust passage.

  In such a configuration, the metal filled in the air-permeable filling chamber or each unit air-permeable filling chamber by microwaves radiated radially from the antenna inserted through the vent hole in the center of the filling housing. The oxide particles are heated to a temperature at which the purification ability can be demonstrated in a short time. Then, all exhaust gas discharged from the internal combustion engine or the like flows into the vent hole path from the upstream side of the exhaust pipe, and then from the vent hole path through the inflow hole formed in the inner peripheral wall or each It flows in the radial direction into the unit breathable filling chamber. Here, the metal oxide particles in the vicinity of the cylindrical inner peripheral wall that contact when the exhaust gas flows into the air permeable filling chamber or each unit air permeable filling chamber have the best microwave supply from the antenna and are the earliest. Since the temperature is increased and the purification ability is exhibited, all the exhaust gas is effectively purified. The exhaust gas purified in the air-permeable filling chamber or each unit air-permeable filling chamber is discharged from the air-permeable filling chamber or each unit air-permeable filling chamber through an exhaust hole formed in the cylindrical outer peripheral wall of the filling housing. It flows out to the exhaust passage in the radial direction and is discharged downstream of the exhaust pipe. Thus, in such a configuration, the direction of the microwave radiated from the antenna and the direction of the exhaust gas flowing through the air-permeable filling chamber or each unit air-permeable filling chamber are the same, so that all exhaust The gas can be brought into contact with metal oxide particles that are heated to the highest temperature and exhibit purification ability.

  Further, in such a configuration, an inflow hole and an exhaust hole are formed in the cylindrical inner peripheral wall and the cylindrical outer peripheral wall, which are the peripheral walls in the longitudinal direction, respectively, and the front wall and the rear wall of the filling housing are respectively formed. Compared with the case where the inflow hole and the exhaust hole are respectively formed, the inflow region and the outflow region of the exhaust gas are wide, so the flow rate of the exhaust gas passing through the air permeable filling chamber or each unit air permeable filling chamber Will be reduced.

  In the configuration of the exhaust gas purification filter, the outer peripheral wall of the filling housing is non-cylindrical, and the exhaust pipe is disposed between the outer surface of the filling housing fitted into the cylindrical exhaust pipe and the inner surface of the exhaust pipe. A configuration is proposed in which an exhaust passage communicating with the downstream side is formed, and an exhaust hole communicating with the exhaust passage is formed in the outer peripheral wall of the filling housing.

  When the outer peripheral wall of the filling housing is non-cylindrical, the exhaust passage is defined between the outer surface of the filling housing and the inner surface of the exhaust pipe by fitting the filling housing into the cylindrical exhaust pipe. In addition, a portion where the outer surface of the filling casing and the inner surface of the exhaust pipe come into contact with each other is generated. For this reason, even when the exhaust path is formed between the outer surface of the filling housing and the inner surface of the exhaust pipe, by screwing the contact portion between the outer surface of the filling housing and the inner surface of the exhaust pipe, The exhaust gas purification filter can be easily fixed in the exhaust pipe.

  Further, in the exhaust gas purification filter configuration, the filling housing has a cylindrical shape including a non-cylindrical outer peripheral wall formed by connecting the bay portions at a predetermined angular interval, and an inner side through which an antenna is inserted. Inner peripheral walls, and a plurality of partition walls extending in the radial direction between the ridges and the inner peripheral wall are provided, and the outer surface of the filling housing fitted into the cylindrical exhaust pipe and the inner surface of the exhaust pipe An exhaust passage communicating with the downstream side of the exhaust pipe is formed between them, and a plurality of unit air-permeable filling chambers defined by each projecting bay portion, partition walls, and inner peripheral walls are continuously provided in the circumferential direction. A configuration is proposed in which an inflow hole communicating with the vent hole passage is formed in the inner peripheral wall of the filling chamber, and an exhaust hole communicating with the exhaust passage is formed in the ridge portion.

  In such a configuration, a cylindrical inner peripheral wall having a vent hole on the inner side from the front wall to the rear wall is disposed along the central longitudinal direction of the filling casing. The front opening of the cylindrical inner peripheral wall is not shielded by the front wall of the filling housing, and the upstream side of the exhaust pipe communicates with the vent hole path. On the other hand, the rear opening of the cylindrical inner peripheral wall is shielded by the rear wall of the filling housing so that the exhaust gas flowing from the upstream side of the exhaust pipe to the vent hole path does not flow to the downstream side of the exhaust pipe. . Therefore, the front wall of the filling housing covers the annular front opening between the non-cylindrical outer peripheral wall and the cylindrical inner peripheral wall, and has a substantially annular shape. Here, the cylindrical inner peripheral wall with the inside as a vent hole path is formed by connecting the inner wall portions of the unit air-permeable filling chambers in the circumferential direction. Moreover, the non-cylindrical outer peripheral wall of the filling housing is formed by coupling the bay-shaped outer wall portions of the unit breathable filling chambers, that is, the bay portions in the circumferential direction.

  Further, in such a configuration, an exhaust path is defined by the outer surface of the filling housing fitted into the exhaust pipe and the inner surface of the exhaust pipe between the protruding bay portions of the outer peripheral wall of the filling housing. This exhaust path communicates only with the downstream side of the exhaust pipe, and a blocking wall is provided in front of the exhaust path so that exhaust gas does not flow directly from the upstream side of the exhaust pipe. This blocking wall is preferably formed integrally with the front wall of the filling housing. Moreover, the contact part of the outer surface of a filling housing | casing and the inner surface of an exhaust pipe arises in each protrusion bay part of an outer peripheral wall. As a result, even if an exhaust path is formed between the outer surface of the filling housing and the inner surface of the exhaust pipe, the exhaust gas purification filter can be easily fixed in the exhaust pipe by screwing the contact portion. can do.

  An antenna that radiates microwaves from the microwave oscillator along the longitudinal direction from the front wall to the rear wall of the filling housing at a position that becomes the center of the filling housing in the vent hole path inside the cylindrical inner peripheral wall Is inserted. Such an antenna radiates microwaves radially in the radial direction toward the metal oxide particles in each unit air-permeable filling chamber. The microwaves radiated from the antenna are gradually absorbed by the metal oxide particles as they travel radially through each unit air-permeable filling chamber, so that the microwaves supplied to the metal oxide particles are near the antenna, that is, It is the largest in the vicinity of the inner peripheral wall of the filled casing and the smallest in the vicinity of the outer peripheral wall. Therefore, the metal oxide particles in each unit air-permeable filling chamber are heated to the highest temperature in the vicinity of the inner peripheral wall and exhibit their effective exhaust gas purification ability.

  The cylindrical inner peripheral wall of the filling housing is formed with innumerable inflow holes that connect the vent hole passages and the respective unit breathable filling chambers, and the exhaust gas that has flowed into the vent hole passages from the upstream side of the exhaust pipe. The gas flows in the radial direction from the vent hole path to each unit breathable filling chamber through the inflow hole. In addition, innumerable exhaust holes are formed in the outer peripheral wall of the filling casing so as to connect each unit breathable filling chamber and the exhaust passage, and the metal oxide particles are purified in contact with each unit breathable filling chamber. The exhaust gas thus discharged flows out radially from each unit air-permeable filling chamber to the exhaust passage.

  In such a configuration, the metal oxide particles filled in each unit breathable filling chamber by microwaves radiated radially from the antenna inserted through the vent hole in the center of the filling housing, The temperature is raised to a temperature at which the purification ability can be demonstrated in a short time. Then, after all exhaust gas discharged from the internal combustion engine or the like flows into the vent hole path from the upstream side of the exhaust pipe, each unit air permeability from the vent hole path via the inflow hole formed in the cylindrical inner peripheral wall It flows radially into the filling chamber. Here, the metal oxide particles in the vicinity of the inner peripheral wall that come into contact when the exhaust gas flows into each unit air-permeable filling chamber has a good microwave supply from the antenna, and is heated up to the highest temperature to exhibit purification ability. Therefore, all exhaust gas is effectively purified. The exhaust gas purified in each unit breathable filling chamber flows out radially from each unit breathable filling chamber to the exhaust passage through the exhaust hole formed in the outer peripheral wall of the filling casing, It is discharged downstream. Thus, in such a configuration, the direction of the microwave radiated by the antenna and the direction of the exhaust gas flowing through the unit air-permeable filling chamber are the same, so that all the exhaust gases are heated to the highest temperature. And can be brought into contact with metal oxide particles that exhibit purification ability.

  Further, in such a configuration, the cylindrical inner peripheral wall and the non-cylindrical outer peripheral wall, which are the peripheral walls in the longitudinal direction, are respectively formed with inflow holes and exhaust holes, and the front wall and the rear wall of the filling housing Compared to the case where the inflow hole and the exhaust hole are respectively formed in the exhaust gas, the exhaust gas inflow region and the outflow region are wide, so that the flow rate of the exhaust gas passing through each unit air-permeable filling chamber is reduced. It becomes.

  Furthermore, in the exhaust gas purification filter, a configuration (claim 6) is proposed in which the average particle diameter of the metal oxide particles is approximately 5 μm to approximately 15 mm.

  When the particle size of the metal oxide particles filled in the air-permeable filling chamber or each unit air-permeable filling chamber is too large, voids generated between the particles increase, and the exhaust gas and the metal oxide particles come into contact with each other. There is a concern that the catalyst capacity may be reduced due to the difficulty of reducing the surface area of the metal oxide particles. For this reason, the average particle diameter of the metal oxide particles is preferably about 15 mm or less. If the particle size of the metal oxide particles is too small, the metal oxide particles should be held in a breathable filling chamber or unit breathable filling chamber provided with inflow holes and exhaust holes in the partition walls. Therefore, the average particle size of the metal oxide particles is preferably about 5 μm or more.

  In the exhaust gas purification filter, a configuration in which the metal oxide particles are made of iron oxide (claim 7) is also proposed.

  In the exhaust gas purification filter of the present invention, a metal oxide is used in the form of particles as a combination of the microwave absorber and the exhaust gas purification catalyst. As the metal oxide, perovskite complex oxide, manganese oxide, cobalt oxide, and the like can be preferably used. However, it is optimal in terms of manufacturing and cost to use iron oxide that is inexpensive and easily available. .

  In the present invention, since the metal oxide as the catalyst is filled in the air permeable filling chamber or each unit air permeable filling chamber in the form of particles having a large surface area, the honeycomb structure or the like carrying the catalyst on the surface thereof, etc. Compared to a conventional structure comprising a carrier, the contact area between the exhaust gas and the catalyst is wide, and the exhaust gas purification ability is excellent. In addition, since the antenna that radiates microwaves radially is inserted through the center of the filling case, the entire area of the air-permeable filling chamber or each unit air-permeable filling chamber is heated faster and its effective. Exhaust gas purification ability can be demonstrated. Further, in the conventional configuration, the microwave absorber, the catalyst, and the carrier supporting these are heated by the microwave supplied from the antenna. Since only the oxide particles are heated, the temperature of the catalyst is increased more quickly than in the conventional configuration. Therefore, in the present invention, since the metal oxide particles as the catalyst can be quickly heated to a high temperature state of about 600 ° C. to 700 ° C. or more and exhibit an excellent purification capability, exhaust gas from an internal combustion engine or the like In addition to harmful substances such as hydrocarbons, carbon monoxide, nitrogen oxides, etc. contained in them, dioxins and other harmful substances that need to be completely burned at a high temperature to be removed can also be used to cold start internal combustion engines, etc. It can be effectively reduced from an earlier time immediately after.

  Further, in the present invention, each metal oxide particle filled in the gas permeable filling chamber or each unit gas permeable filling chamber can be slightly moved by the flow of exhaust gas. The flow path of the exhaust gas formed between the material particles is not constant and changes depending on the flow rate of the exhaust gas. For this reason, the filled casing of the present invention does not cause clogging in the exhaust gas flow path due to soot contained in the exhaust gas, and can be used for a long time without maintenance. In addition, in the present invention, when replacing the filling housing, if only the metal oxide particles filled in the breathable filling chamber or each unit breathable filling chamber are replaced, the same effect as that of a new article can be obtained. It can be used as a performance, and the material cost at the time of replacement can be reduced.

  Also, unlike the conventional configuration in which the catalyst that is a microwave absorber is carried on the surface, and the temperature of the catalyst and the carrier is integrally raised by the microwave from the antenna, in the present invention, Only the metal oxide particles filled in the breathable filling chamber or each unit breathable filling chamber are individually heated by microwaves. For this reason, even if a temperature difference occurs between the vicinity of the antenna in the air-permeable filling chamber or the unit air-permeable filling chamber and the area away from the antenna due to the difference in the temperature of the supplied microwave, No difference in thermal expansion occurs due to the temperature difference between parts such as the carrier, thermal stress does not act, and there is no possibility that the filled casing will be cracked or broken.

  Furthermore, in the present invention, a process for supporting the catalyst and the microwave absorber by immersing or drying on the surface of the carrier, which is necessary in the conventional configuration, is not required, so that the production can be performed in a short time and at a low cost. Is possible.

  Further, in the present invention, when the filling region filled with the metal oxide particles is divided into a plurality of unit air-permeable filling chambers, the difference in particle size and mass of the metal oxide particles, the internal combustion engine The degree of uneven distribution of the metal oxide particles in the filling region caused by vibrations from the exhaust gas is reduced, and the deterioration of the air permeability and purification capability of the exhaust gas purification filter due to such uneven distribution can be minimized.

  Further, in the configuration in which a plurality of unit breathable filling chambers are continuously provided in the circumferential direction, the central wall of the filling casing is formed by the inner wall portion of each unit breathable filling chamber being continuously formed in the circumferential direction. An antenna peripheral wall is formed along the direction with the inside being an antenna insertion hole. For this reason, the contact between the antenna and the metal oxide particles does not occur, whereby the antenna can be easily inserted into the center of the filled casing, and the durability of the antenna is improved.

  Further, in the present invention, the filling housing is provided with a cylindrical inner peripheral wall having a vent hole path inside along the central longitudinal direction, and further, an exhaust gas is provided between the outer surface of the filling housing and the inner surface of the exhaust pipe. When an exhaust passage communicating with the downstream side of the pipe is formed, an inflow hole communicating with the vent hole passage is formed on the inner peripheral wall of the filling housing, and an exhaust hole communicating with the exhaust passage is formed on the outer peripheral wall. Since the direction of the microwave radiated from the antenna and the direction of the exhaust gas flowing through the air-permeable filling chamber or each unit air-permeable filling chamber are the same, all the exhaust gases discharged from the internal combustion engine etc. The metal oxide particles are brought into contact with the metal oxide particles which are heated to the highest temperature and exhibit their effective exhaust gas purification ability. For this reason, in addition to harmful substances such as hydrocarbons, carbon monoxide, nitrogen oxides, etc. contained in exhaust gas, harmful substances such as dioxins are also effective from an earlier point immediately after the cold start of an internal combustion engine, etc. Can be reduced. Incidentally, in a carrier such as a honeycomb structure having a conventional structure, an infinite number of ventilation communication paths along the longitudinal direction are formed in parallel to the radial direction. Exhaust gas that passes through the ventilation communication passage in the vicinity of the area where the temperature rises well is purified, but the exhaust gas that passes away from the antenna and passes through the ventilation communication passage in the area that is difficult to be heated is hardly purified. It has become.

  Further, in such a configuration, the inflow hole and the exhaust hole are formed in the outer peripheral wall and the inner peripheral wall, which are peripheral walls in the longitudinal direction, and the exhaust gas inflow region and the outflow region are wide. Therefore, the flow rate of the exhaust gas passing through the air-permeable filling chamber or each unit air-permeable filling chamber is reduced, and the residence time of the exhaust gas in the air-permeable filling chamber or each unit air-permeable filling chamber is increased. As a result, the exhaust gas comes into contact with the metal oxide particles more, and the purification ability of the exhaust gas purification filter is improved. Further, in such a configuration, since the antenna is inserted through a space called a vent passage inside the cylindrical inner peripheral wall, this can be easily performed.

  Further, in the present invention, when the outer peripheral wall of the filling casing is non-cylindrical, the filling casing is fitted into the cylindrical exhaust pipe so that the outer surface of the filling casing and the inner surface of the exhaust pipe are interposed. In addition, an exhaust path is defined, and a portion where the outer surface of the filling housing contacts the inner surface of the exhaust pipe is generated. For this reason, even when the exhaust path is formed between the outer surface of the filling housing and the inner surface of the exhaust pipe, by screwing the contact portion between the outer surface of the filling housing and the inner surface of the exhaust pipe, The exhaust gas purification filter can be easily fixed in the exhaust pipe.

  Here, in the exhaust gas purifying filter, the average particle diameter of the metal oxide particles filled in the breathable filling chamber or each of the unit breathable filling chambers is set to about 5 μm to about 15 mm, so that the exhaust gas is discharged from the internal combustion engine or the like. Since the exhaust gas smoothly passes through the gas permeable filling chamber or each unit gas permeable filling chamber while being in good contact with the metal oxide particles having a large surface area, the exhaust gas can be effectively purified.

  Further, the exhaust gas of the present invention having an effective exhaust gas purification capability by using iron oxide particles that are inexpensive and easily available as the metal oxide particles filled in the breathable filling chamber or each unit breathable filling chamber. A purification filter can be manufactured efficiently at low cost, in a short time.

Hereinafter, embodiments of an exhaust gas purification filter of the present invention will be described with reference to the accompanying drawings.
First, Embodiment A will be described with reference to FIGS. In the exhaust gas purification filter 1a of Embodiment A, the filled casing 2a has a flower-shaped cylindrical outer peripheral wall 20a formed by connecting eight substantially semicircular protruding bay portions 25 at 45 degree intervals, and openings at both ends thereof. The front wall 21a and the rear wall 22a are covered with the cylindrical exhaust pipe 10. The filling housing 2a is made of stainless steel having heat resistance. Between each protruding bay portion 25 of the outer peripheral wall 20a, an air gap is defined by the outer surface of the filling housing 2a and the inner surface of the cylindrical exhaust pipe 10, and the air gap is defined as an exhaust passage 12a. The front wall 21a of the filling housing 2a has a disk shape whose peripheral edge is in contact with the inner surface of the exhaust pipe 10, covers the front opening of the cylindrical outer peripheral wall 20a, and shields the exhaust passage 12a forward. . A mounting hole 27 for inserting the antenna into the filling housing 2a is formed at the center of the front wall 21a. On the other hand, the rear wall 22a of the filling housing 2a has a flower-like plate shape that uniformly covers the rear opening of the outer peripheral wall 20a.

  As shown in FIG. 1, the inside of the filling housing 2 a is a breathable filling chamber 3. In the center of the air-permeable filling chamber 3, an antenna that radiates microwaves extends from the mounting hole 27 formed in the front wall 21a of the filling case 2a along the longitudinal direction of the rear wall 22a of the filling case 2a. Is inserted. This antenna uses a circular radiation waveguide 15 made of stainless steel having heat resistance. As shown in FIG. 4, slits 16 having a width of 1 mm and a length of 60 mm are formed on the tube wall at a pitch of 20 mm in the circular radiating waveguide 15, and microwaves are radially directed toward the breathable filling chamber 3. Are emitted radially. Further, a ferrite body 18 that is a microwave absorber is provided at the end position of the circular radiation waveguide 15 so that the microwave does not leak to the downstream side of the exhaust pipe 10 or is not reflected at the end position. . The microwave is generated by a microwave oscillator 13 that is controlled to start simultaneously with the start of an internal combustion engine (not shown), and one end is connected to the microwave oscillator 13 and the other end is connected to the circular radiation waveguide 15. It propagates through the circular waveguide 17 to the circular radiating waveguide 15. Then, it is radiated to the air-permeable filling chamber 3 through the slit 16 of the circular radiating waveguide 15 and propagates to the ferrite body 18 provided at the end position of the circular radiating waveguide 15 to be absorbed by the ferrite body 18. Is done.

  The air-permeable filling chamber 3 inside the filling case 2a is filled with metal oxide particles that absorb microwaves and raise their temperature, and have excellent exhaust gas purification ability. Iron oxide particles 8 are used as the metal oxide particles. The iron oxide particles 8 have a particle diameter of 5 to 10 mm obtained by granulating iron oxide having a particle diameter of approximately 1 μm. The iron oxide particles 8 are well heated by microwaves and effectively purify the exhaust gas at 350 ° C. or higher.

  The breathable filling chamber 3 is partitioned by the outer peripheral wall 20a, the front wall 21a, and the rear wall 22a of the filling housing 2a. An inflow hole 30 a that communicates with the upstream side of the exhaust pipe 10 is formed in the front wall 21 a of the filling housing 2 a so that the exhaust gas flows into the air-permeable filling chamber 3. Further, the rear surface wall 22a of the filling housing 2a covers the entire surface so that the exhaust gas flowing between the iron oxide particles 8 in the breathable filling chamber 3 flows out of the breathable filling chamber 3 well. Innumerable exhaust holes 31a are formed, and innumerable exhaust holes 31b communicating with the exhaust passage 12a defined by the outer surface of the filling housing 2a and the inner surface of the exhaust pipe 10 are also formed near the rear end of the outer peripheral wall 20a. Has been. Here, in the outer peripheral wall 20a, the exhaust holes 31b are formed only in the vicinity of the rear end of the outer peripheral wall 20a because the exhaust gas flowing into the air-permeable filling chamber 3 has a short passage distance through the air-permeable filling chamber 3, that is, It is possible to prevent the exhaust passage 12a from flowing out immediately from the exhaust hole formed near the inflow hole 30a, which has a low resistance to the flow of the exhaust gas, and to effectively utilize the entire breathable filling chamber 3 to This is to effectively purify the gas. The inflow holes 30a and the exhaust holes 31a and 31b formed innumerably in each wall portion of the filling casing 2a are formed by forming through-holes of φ2.0 mm with a pitch of 3.2 mm and an aperture ratio of 35.7%. .

  In the embodiment A, the circular radiation waveguide 15 is inserted along the longitudinal direction in the center of the air-permeable filling chamber 3, and the circular radiation waveguide 15 is filled in the air-permeable filling chamber 3. A microwave is radiated in a radial direction toward the iron oxide particles 8 formed. The microwave radiated from the circular radiation waveguide 15 propagates radially in the air-permeable filling chamber 3 in the radial direction and is well absorbed by the iron oxide particles 8 in the entire region of the air-permeable filling chamber 3. The microwave absorbed by the iron oxide particles 8 is used to increase the temperature of only the iron oxide particles 8, and the iron oxide particles 8 are heated to a temperature of about 600 ° C. to 700 ° C. or higher earlier than the conventional configuration. The temperature is raised to a state and the exhaust gas purification ability is exhibited. Exhaust gas discharged from the internal combustion engine flows into the air-permeable filling chamber 3 through innumerable inflow holes 30a formed in the front wall 21a of the filling housing 2a (indicated by arrows in FIGS. 1 and 3). . The exhaust gas passes uniformly through the entire area of the air-permeable filling chamber 3 up to the rear part of the filling housing 2a, and is excellent in the iron oxide particles 8 filled with particles having a wide contact area with the exhaust gas. Contact. In the rear portion of the filling housing 2a, the exhaust gas flows out to the exhaust passage 12a through the exhaust hole 31b formed near the rear end of the outer peripheral wall 20a of the filling housing 2a, or the filling housing 2a flows to the rear wall 22a, flows out to the downstream side of the exhaust pipe 10 through the exhaust hole 31a formed in the rear wall 22a, and is exhausted from the subsequent exhaust pipe 10 to the atmosphere. . In such a configuration, the exhaust gas from the internal combustion engine is quickly heated to a high temperature state of about 600 ° C. to 700 ° C. or more, and has a wide surface area and excellent catalytic action, and an air-permeable filling chamber. In addition to harmful substances such as hydrocarbons, carbon monoxide, nitrogen oxides, etc. contained in the exhaust gas, dioxins that need to be completely burned at high temperatures to be removed It is also possible to effectively reduce harmful substances such as those from an earlier time immediately after the cold start of the internal combustion engine.

  In the embodiment A, each iron oxide particle 8 is filled in the air-permeable filling chamber 3 in an independent state. Some play can be done. For this reason, the flow path of the exhaust gas formed between the iron oxide particles 8 is not always constant, and the flow path of the exhaust gas is not clogged by soot contained in the exhaust gas. . Thus, the exhaust gas purification filter 1a can be used for a long time without maintenance.

  Furthermore, in Embodiment A, since the iron oxide particles 8 are filled in the air-permeable filling chamber 3 in an independent state, the iron oxide particles 8 are individually heated by microwaves. For this reason, the degree of temperature rise differs depending on the amount of microwaves supplied from the circular radiating waveguide 15 between the vicinity of the antenna of the air-permeable filling chamber 3 and the region away from the antenna. Even if there is a temperature difference between the regions, there is no difference in the amount of thermal expansion between the parts as in the case of the carrier of the conventional configuration, and no thermal stress is generated, and there is a risk that the filled casing 2a will be cracked or damaged. There is no.

  In the present embodiment A, the exhaust gas that has flowed into the air-permeable filling chamber 3 is made to flow out of the air-permeable filling chamber 3 well, so that the exhaust holes 31a and 31b are provided in the rear wall 22a and the outer peripheral wall 20a, respectively. However, the exhaust hole may be formed only in one wall portion that defines the air-permeable filling chamber 3. In addition, a cylindrical antenna peripheral wall having an antenna insertion hole on the inside is provided at a position where the antenna at the center of the filling housing 2a is inserted, and the air-permeable filling chamber 3 is filled with the iron oxide particles 8 after the inside. However, the antenna may be easily inserted into the filling housing 2a. In such a configuration, since the circular radiation waveguide 15 and the iron oxide particles 8 do not come into contact with each other, the durability of the circular radiation waveguide 15 is improved, and the entrance of the iron oxide particles 8 in the air-permeable filling chamber 3 is improved. Can be easily replaced

  Next, Embodiment B will be described with reference to FIGS. In the exhaust gas purification filter 1b of Embodiment B, the cylindrical outer peripheral wall 20b of the filling housing 2b includes eight substantially semicircular protruding bay portions 26 forming the outer wall portion of the unit air-permeable filling chamber 4 at 45 ° intervals. It is formed by coupling and forms a flower-shaped cylinder. In addition, a cylindrical inner peripheral wall 23 is disposed in the filling casing 2b along the longitudinal direction of the center. The inner peripheral wall 23 has an inside through which an antenna is inserted and communicated with the upstream side of the cylindrical exhaust pipe 10. The pore path 35 is used. Further, eight partition walls 24 formed integrally with the outer peripheral wall 20b are passed in the radial direction from between the respective protruding bay portions 26 of the outer peripheral wall 20b to the inner peripheral wall 23. And the both ends opening of the longitudinal direction of the eight unit air permeable filling chambers 4 divided by each ridge part 26, the partition 24, 24, and the inner peripheral wall 23 is the front wall 21b arrange | positioned by the filling housing | casing 2b. The rear wall 22b is collectively cut off. That is, in the embodiment B, the filling housing 2b includes a cylindrical outer peripheral wall 20b, a cylindrical inner peripheral wall 23, eight radial partition walls 24, a cylindrical outer peripheral wall 20b, and a cylindrical inner peripheral wall 23. It consists of a front wall 21b and a rear wall 22b that cover both ends of the substantially annular opening, and eight unit air-permeable filling chambers 4 partitioned by these wall portions are connected in the circumferential direction around the antenna. The filling housing 2b is fitted into the cylindrical exhaust pipe 10. Here, the filling housing 2b is made of stainless steel having heat resistance. In the present embodiment B, the outer peripheral wall 20b of the filling housing 2b and the eight partition walls 24 are integrally formed in order to facilitate the manufacturing process, but each wall portion is formed individually. There may be. Further, a front wall 21b and a rear wall 22b that collectively cover both longitudinal openings of all the unit air-permeable filling chambers 4 are provided in the filling housing 2b. You may provide the front wall part and back wall part which cover both ends opening. In such a case, the front wall 21b and the rear wall 22b of the filling housing 2b are formed by a plurality of front wall portions and rear wall portions of the unit breathable filling chamber 4 being connected.

  Between each protruding bay portion 26 of the filling housing 2b, an air gap is defined by the outer surface of the filling housing 2b and the inner surface of the exhaust pipe 10, and the exhaust passage 12b communicates with the downstream side of the exhaust pipe 10. It is said. A vent hole path 35 is formed inside the cylindrical inner peripheral wall 23 of the filling housing 2b. The vent hole path 35 communicates with the upstream side of the exhaust pipe 10 through the longitudinal front opening of the cylindrical inner peripheral wall 23. Accordingly, the front wall 21b of the filling housing 2b is formed in a circular plate shape in which a hole portion having the same shape as the vent hole path 35 is formed at the center and the peripheral edge is in contact with the inner surface of the exhaust pipe 10. In addition to shielding in front, the vent hole path 35 and the upstream side of the exhaust pipe 10 are communicated. On the other hand, the rear wall 22b of the filling housing 2b has a flower-like plate shape covering the rear opening of the cylindrical outer peripheral wall 20b of the filling housing 2b formed by coupling the substantially semicircular protruding bay portions 26. The rear openings of the two unit air-permeable filling chambers 4 are collectively covered, and the rear opening of the inner peripheral wall 23 is also blocked so that the vent hole path 35 inside the cylindrical inner peripheral wall 23 does not communicate with the downstream side of the exhaust pipe 10. It is supposed to be. Here, the inner peripheral wall 23 of the filling housing 2b has a cylindrical shape that covers the inner openings in the radial direction of the eight unit air-permeable filling chambers 4 together with the inner side being a vent hole path 35. The peripheral wall 23 may be formed by providing each unit breathable filling chamber 4 with an inner wall portion that covers the inner opening in the radial direction of each unit breathable filling chamber 4 and a plurality of such inner wall portions. good.

  An antenna that radiates microwaves is inserted into the vent hole path 35 along the longitudinal direction at the center thereof from the front wall 21b to the rear wall 22b of the filling housing 2b. The antenna used in the present embodiment B is the same as that of the embodiment A, and is a stainless circular radiation waveguide 15 in which slits having a width of 1 mm and a length of 60 mm are formed at a pitch of 20 mm on the tube wall of the waveguide. is there. And the ferrite body 18 which absorbs a microwave is provided in the terminal position. The microwave is generated by a microwave oscillator 13 that is controlled to start simultaneously with the start of an internal combustion engine (not shown), and one end is connected to the microwave oscillator 13 and the other end is connected to the circular radiation waveguide 15. It propagates through the circular waveguide 17 to the circular radiating waveguide 15. Then, it is radiated radially toward each unit air-permeable filling chamber 4 through the slit 16 of the circular radiating waveguide 15.

  Further, in the eight-unit air-permeable filling chamber 4 continuously provided in the circumferential direction inside the filling housing 2b, the metal absorbs microwaves and rises in temperature, and itself has an excellent exhaust gas purification ability. Filled with oxide particles. Iron oxide particles 8 are used as the metal oxide particles, and the iron oxide particles 8 are also the same as those in the embodiment A, and have a particle diameter of 5 to 10 mm formed by granulating iron oxide having a particle diameter of approximately 1 μm. Is. The iron oxide particles 8 are well heated by microwaves and effectively purify the exhaust gas at 350 ° C. or higher.

  Each unit breathable filling chamber 4 is formed by the outer peripheral wall 20b and the inner peripheral wall 23 of the filling housing 2b in the radial direction, the partition walls 24 and 24 in the circumferential direction, and the front wall 21b and the rear wall 22b in the longitudinal direction. Each one is divided. An infinite number of inflow holes 30b communicating with the vent hole path 35 are formed in the inner peripheral wall 23 of the filling housing 2b having the inner vent hole path 35 over the entire length thereof. Exhaust gas from the internal combustion engine flows into each unit breathable filling chamber 4 via the communicating vent hole path 35. In addition, the outer peripheral wall 20b of the filling housing 2b is provided with an exhaust gas so that the exhaust gas flowing between the iron oxide particles 8 in each unit breathable filling chamber 4 flows out from each unit breathable filling chamber 4 well. An infinite number of exhaust holes 31c communicating with the exhaust passage 12b defined by the outer surface of the filling housing 2b and the inner surface of the exhaust pipe 10 are formed over the entire length. The exhaust gas flows out from the unit air-permeable filling chambers 4 to the downstream side of the exhaust pipe 10 through the exhaust passage 12 b communicating with the downstream side of the exhaust pipe 10. Here, the inflow holes 30b and the exhaust holes 31c respectively formed in the inner peripheral wall 23 and the outer peripheral wall 20b of the filling housing 2b are the same as those in the embodiment A, and a through hole of φ2.0 mm has a pitch of 3 .2 mm and an aperture ratio of 35.7%.

  In the present embodiment B, the circular radiation waveguide 15 is inserted along the longitudinal direction at the center position inside the cylindrical inner peripheral wall 23 of the filling housing 2b. A microwave is radiated radially toward the iron oxide particles 8 filled in the unit air-permeable filling chamber 4. Microwaves radiated from the circular radiating waveguide 15 propagate radially in the respective unit air-permeable filling chambers 4 in the radial direction, and are favorably applied to the iron oxide particles 8 in the entire region of each unit air-permeable filling chamber 4. Absorbed. The microwave absorbed by the iron oxide particles 8 is used to increase the temperature of only the iron oxide particles 8, and the iron oxide particles 8 are heated to a temperature of about 600 ° C. to 700 ° C. or higher earlier than the conventional configuration. The temperature is raised to a state and the exhaust gas purification ability is exhibited. Exhaust gas discharged from the internal combustion engine flows into the vent hole path 35 from the upstream side of the exhaust pipe through the front opening of the cylindrical inner peripheral wall 23 (indicated by arrows in FIGS. 5 and 6). And it flows equally in the radial direction from the vent hole path 35 to each unit air-permeable filling chamber 4 through the infinite number of inflow holes 30b formed in the inner peripheral wall 23 of the filling housing 2b. The exhaust gas that has flowed into each unit air-permeable filling chamber 4 has the shortest distance from the circular radiation waveguide 15 and the iron oxide particles 8 in the vicinity of the inner peripheral wall 23 that exhibits the exhaust gas purification ability by being heated to the highest temperature. It contacts and distribute | circulates the whole area | region of each unit ventilation filling chamber 4 equally in radial direction. Here, the iron oxide particles 8 in each unit air-permeable filling chamber 4 are filled with particles having a wide contact area with the exhaust gas and are in good contact with the exhaust gas. Then, the exhaust gas flows out to the exhaust passage 12b through the exhaust hole 31c formed in the outer peripheral wall 20b of the filling housing 2b, and is exhausted from the downstream side of the subsequent exhaust pipe 10 to the atmosphere. . As described above, in such a configuration, the exhaust gas from the internal combustion engine is quickly heated to a high temperature state of about 600 ° C. to 700 ° C. or more, and has a wide surface area and excellent catalytic action, and each of the iron oxide particles 8. Good contact is made in the unit breathable filling chamber 4. Furthermore, since the direction of the microwave radiated from the circular radiation waveguide 15 and the direction of the exhaust gas flowing through each unit air-permeable filling chamber 4 are the same, all the exhaust gases discharged from the internal combustion engine are Then, the oxide particles 8 are brought into contact with the oxide particles 8 in the vicinity of the inner peripheral wall 23 of the filled casing 2b, which is heated to the highest temperature and exhibits its effective exhaust gas purification ability. For this reason, in addition to harmful substances such as hydrocarbons, carbon monoxide, and nitrogen oxides contained in the exhaust gas, harmful substances such as dioxins that need to be completely burned at a high temperature to be removed are also used in internal combustion engines. Can be effectively reduced from an earlier time immediately after the cold start.

  Further, in the present embodiment B, each iron oxide particle 8 is filled in each unit air-permeable filling chamber 4 in an independent state. Therefore, each iron oxide particle is caused by circulation of exhaust gas. 8 can make some play. For this reason, the flow path of the exhaust gas formed between the iron oxide particles 8 is not always constant, and the flow path of the exhaust gas is not clogged by soot contained in the exhaust gas. . Thus, the exhaust gas purification filter 1b can be used for a long time without maintenance.

  Furthermore, in this embodiment B, since the iron oxide particles 8 are filled in the unit air-permeable filling chambers 4 in an independent state, the iron oxide particles 8 are individually heated by microwaves. . For this reason, the degree of temperature rise differs depending on the difference in the amount of microwaves supplied from the circular radiating waveguide 15 between the vicinity of the antenna of each unit breathable filling chamber 4 and the region away from the antenna. Even if a temperature difference occurs between the respective regions of the chamber 4, there is no difference in thermal expansion amount between parts or thermal stress as in the conventional carrier, and there is no crack or crack in the filled housing 2b. There is no risk of damage.

  Further, in the present embodiment B, since the filling region filled with the iron oxide particles 8 is formed by being divided into the plurality of unit air-permeable filling chambers 4, the iron oxide particles 8 are unevenly distributed in the filling region. As a result, the deterioration of the air permeability and purification capability of the exhaust gas purification filter 1b due to such uneven distribution can be minimized.

  In this configuration, the inflow hole 30b and the exhaust hole 31c are formed in the outer peripheral wall 20b and the inner peripheral wall 23, which are peripheral walls in the longitudinal direction, respectively, and the exhaust gas inflow region and the outflow region are wide. Therefore, the flow rate of the exhaust gas flowing through each unit breathable filling chamber 4 is decreased, and the residence time of the exhaust gas in each unit breathable filling chamber 4 is increased. For this reason, the exhaust gas and the iron oxide particles 8 are in good contact with each other in each unit air-permeable filling chamber 4, and the exhaust gas is more effectively purified. Further, in such a configuration, the insertion position of the circular radiating waveguide 15 is an air gap called the vent hole path 35, so that this can be easily performed.

  Further, in the present embodiment B, an exhaust passage 12b is defined by the outer surface of the filling housing 2b and the inner surface of the exhaust pipe 10 between the projecting bay portions 26 of the outer peripheral wall 20b of the filling housing 2b. At the same time, in each projecting bay portion 26 of the outer peripheral wall 20b, a contact portion between the outer surface of the filling housing 2b and the inner surface of the exhaust pipe 10 is generated. Therefore, the exhaust gas purification filter 1b in which the exhaust passage 12b is formed between the outer surface of the filling housing 2b and the inner surface of the exhaust pipe 10 can be easily attached to the exhaust pipe 10 by screwing the contact portion. Can be fixed.

  In the present embodiment B, in order to allow the exhaust gas from the internal combustion engine to flow into the unit air permeable filling chamber 4 well, an inflow hole is formed in the front wall 21b in addition to the inner peripheral wall 23 of the filling housing 2b. May be. However, in such a case, the inflow hole is formed only in the vicinity of the center of the exhaust pipe 10 of the front wall 21b so that the exhaust gas flowing into each unit air-permeable filling chamber 4 does not immediately flow out to the exhaust path 12b. There is a need to. Further, in order to allow the exhaust gas to flow out from each unit air-permeable filling chamber 4, an exhaust hole may be formed in the outer edge portion corresponding to the petal portion of the rear wall 22b of the filling case 2b which is a flower shape. Here, the exhaust holes are formed only in the outer edge portion of the rear wall 22b because the exhaust gas flowing into the unit air-permeable filling chambers 4 from the inflow holes 30b communicating with the vent hole passages 35 is immediately generated in the exhaust pipe 10. This is to prevent outflow to the downstream side. When there is a region with a short distance from the inflow hole to the exhaust hole in the filling housing, it is necessary to consider that the exhaust gas does not flow unevenly in the region.

  The exhaust gas purification filter of the present invention can effectively purify exhaust gas discharged from factories, treatment plants, etc. in addition to exhaust gas discharged from internal combustion engines such as automobiles and motorcycles. . Such an exhaust gas purification filter is not limited to the above-described embodiment in the configuration of the filling housing, the antenna, the metal oxide particles, and the like. A catalyst such as the above may be used together, or the outer peripheral wall of the filled housing may be cylindrical. It is also preferable that the metal oxide particles be iron oxide particles having a particle diameter of 2 to 5 mm formed by granulating iron oxide having a particle diameter of approximately 1 μm. The diameter of the inflow hole and the exhaust hole formed in the portion must be taken into consideration so that the metal oxide particles do not leak from the air-permeable filling chamber or each unit air-permeable filling chamber. Further, a coaxial cable or the like can be preferably used instead of the waveguide.

  It is also preferable to change the filling rate and average particle size of the metal oxide particles. For example, fine particles having an average particle size of 10 μm may be filled at a filling rate of about 60%. In such a case, the metal oxide particles are diffused by the flow of the exhaust gas flowing in the breathable filling chamber or the unit breathable filling chamber, and the exhaust gas and the metal oxide particles come into contact with each other in this state. Therefore, the exhaust gas can be effectively purified. Further, by making the metal oxide particles to be filled into a porous shape, the surface area is increased and the temperature can be easily raised, so that the purification capability can be improved, and the exhaust gas purification filter can be reduced in weight.

It is a vertical side view of the exhaust gas purification filter 1a. FIG. 9 is a partial perspective view showing the state in which the rear wall 22a of the filling housing 2a is removed and the filling housing 2a is fitted into the cylindrical exhaust pipe 10 according to Embodiment A, as viewed from the rear. It is a longitudinal front view of the exhaust gas purification filter 1a, which is shown longitudinally at the rear end position of the outer peripheral wall 20a in which the exhaust holes 31b are formed. It is a fragmentary perspective view of the circular radiation | emission waveguide 15 which concerns on Embodiment A and Embodiment B. FIG. It is a vertical side view of the exhaust gas purification filter 1b. It is a vertical front view of the exhaust gas purification filter 1b.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Exhaust-gas purification filter 2a, 2b Filling housing | casing 3 Breathable filling chamber 4 Unit breathable filling chamber 8 Iron oxide particle 10 Cylindrical exhaust pipe 12a, 12b Exhaust path 13 Microwave oscillator 15 Circular radiation waveguide (antenna )
16 slit 17 circular waveguide 18 ferrite body 20a, 20b outer peripheral wall 21a, 21b front wall 22a, 22b of the filling casing rear wall 23 of the filling casing 23 inner peripheral wall of the filling casing 24 partition wall of the filling casing 25 Cavity bay of outer wall 26 Cavity bay (outer wall) of unit breathable filling chamber
27 Mounting hole 30a, 30b Inflow hole 31a, 31b, 31c Exhaust hole 35 Vent hole path

Claims (7)

In an exhaust gas purification filter that purifies exhaust gas from an internal combustion engine of an automobile, etc., by catalytic action of a metal oxide that is enclosed in the exhaust pipe and heated by microwaves,
The cylindrical outer peripheral wall is covered with the front wall and the rear wall, and the inside is made into a breathable filling chamber. An antenna that radiates microwaves from a microwave oscillator is inserted along the direction, and the air-permeable filling chamber is filled with metal oxide particles that are heated by microwaves, and further the wall section that defines the air-permeable filling chamber The exhaust gas is characterized in that an inflow hole communicating with the upstream side of the exhaust pipe and an exhaust hole for discharging the exhaust gas flowing between the metal oxide particles to the downstream side of the exhaust pipe are formed. Purification filter. In an exhaust gas purification filter that purifies exhaust gas from an internal combustion engine of an automobile, etc., by catalytic action of a metal oxide that is enclosed in the exhaust pipe and heated by microwaves,
A plurality of unit air-permeable filling chambers that are partitioned by an outer wall portion and an inner wall portion in the radial direction, by a partition wall in the circumferential direction, and by a front wall portion and a rear wall portion in the longitudinal direction, are continuously provided in the circumferential direction. It is provided with a filling housing that is built in the exhaust pipe, and an antenna that radiates microwaves from the microwave oscillator is inserted in the center along the longitudinal direction, and the temperature is raised by microwaves in each unit air-permeable filling chamber The wall portion that is filled with the metal oxide particles and further defines each unit air-permeable filling chamber has an inflow hole that communicates with the upstream side of the exhaust pipe, and exhaust gas that has circulated between the metal oxide particles downstream of the exhaust pipe. An exhaust gas purifying filter, characterized in that exhaust holes for discharging to the side are respectively formed.   A cylindrical inner peripheral wall is disposed along the central longitudinal direction of the filling casing, and an inner side of the inner peripheral wall serves as a vent hole path through which an antenna is inserted and communicates with the upstream side of the exhaust pipe. An exhaust passage communicating with the downstream side of the exhaust pipe is formed between the outer surface of the exhaust pipe and the inner surface of the exhaust pipe. An inflow hole communicating with the vent hole path is formed on the inner peripheral wall of the filling housing, and an exhaust passage is formed on the outer peripheral wall. The exhaust gas purification filter according to claim 1 or 2, wherein exhaust holes communicating with the exhaust gas are formed respectively.   The outer peripheral wall of the filling housing is non-cylindrical, and an exhaust passage communicating with the downstream side of the exhaust pipe is formed between the outer surface of the filling housing fitted in the cylindrical exhaust pipe and the inner surface of the exhaust pipe. The exhaust gas purification filter according to claim 3, wherein an exhaust hole communicating with the exhaust passage is formed in the outer peripheral wall of the filling casing.   The filling housing has a non-cylindrical outer peripheral wall in which the ridges are coupled at a predetermined angular interval, a cylindrical inner peripheral wall with a vent hole passage through which the antenna is inserted, and between each bay A plurality of partition walls extending in the radial direction are provided on the peripheral wall, and communicate with the downstream side of the exhaust pipe between the outer surface of the filling housing fitted inside the cylindrical exhaust pipe and the inner surface of the exhaust pipe. An exhaust passage is formed, and a plurality of unit air-permeable filling chambers that are partitioned by each protruding bay portion, partition wall, and inner peripheral wall are connected in the circumferential direction, and the inner peripheral wall of each unit air-permeable filling chamber is formed from a vent hole passage. 3. The exhaust gas purification filter according to claim 2, wherein the communicating inflow hole is formed with an exhaust hole communicating with the exhaust passage in the bay portion.   The exhaust gas purification filter according to any one of claims 1 to 5, wherein the average particle diameter of the metal oxide particles is about 5 µm to about 15 mm. The exhaust gas purification filter according to any one of claims 1 to 6, wherein the metal oxide particles are made of iron oxide.

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