JP2006247532A - Filter device for purifying exhaust gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter device for purifying an exhaust gas in which a particulate material (PM) is prevented from being deposited on an end surface in an exhaust gas inflow side while both improving a collection efficiency of PM and preventing an increase of exhaust gas pressure loss. <P>SOLUTION: The filter device for purifying an exhaust gas comprises: a plurality of exhaust gas flow paths; and a filter 3 disposed in the exhaust gas flow paths, the exhaust gas flow path having: a filter introduction portion 100 for introducing the exhaust gas to the filter 3; and a filter bypass portion 200 for diverging the filter introduction portion 100 to the exhaust gas flow paths adjacent thereto to be bypassed, the filter bypass portion 202 in the most upstream being disposed toward the upper stream side than the filter introduction portion 100 in the most upstream and opened to an end surface in an exhaust gas inlet side, wherein the exhaust gas firstly passes through the filter bypass portion 202 in the most upstream and therefore PM can be prevented from being deposited on an end surface in an exhaust gas inflow side, whereby hardly causing clogging of PM on the end surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust gas purification filter device that collects particulate matter (hereinafter referred to as PM) in exhaust gas from a diesel engine or the like.

  Since exhaust gas from diesel engines, etc. contains PM composed of carbon fine particles, SOF, sulfates, etc., it is necessary to remove PM before discharging to discharge clean exhaust gas. Since it is difficult to remove this PM with a normal oxidation catalyst, a three-way catalyst, etc., a method of removing it by oxidation after collecting it on a filter is common.

  As such a filter, a honeycomb body made of heat-resistant ceramics such as cordierite and having a large number of cells, an inflow side cell clogged at the downstream end, and an upstream end adjacent to the inflow side cell A wall flow type in which an outflow side cell clogged with the above is formed is widely used. In this filter, the exhaust gas flowing into the inflow side cell passes through the cell partition wall and is discharged from the outflow side cell, but when the exhaust gas passes through the cell partition wall, PM is collected in the pores of the cell partition wall. When PM is collected to some extent, PM collected by heating with a heater is burned to regenerate the filter function.

  However, with such a filter, when the amount of PM trapped is large, the amount of heat generated by combustion during regeneration is large and may be damaged by heat shock. In addition, the manufacturing cost is high. Therefore, in recent years, several metal filter devices have been proposed.

  For example, in Japanese Patent Application Laid-Open No. 09-262414, a corrugated plate made of a thin metal plate and a flat plate made of a metal non-woven fabric are alternately laminated, and an inflow side cell clogged at a downstream end portion is adjacent to the inflow side cell. A filter is described which forms an outflow side cell clogged at an upstream end. Further, JP 2002-113798 A discloses an inflow side cell in which flat plates and corrugated plates made of a metal nonwoven fabric are alternately laminated and clogged at a downstream end, and an upstream end adjacent to the inflow side cell. And a filter formed with an outflow side cell clogged with.

  According to these filters, PM in the exhaust gas is collected in the metal nonwoven fabric. And even if it performs the regeneration process which burns PM by heating, since it is metal, a heat shock is small and damage can be suppressed. However, since these filters are all wall flow type filters, the exhaust pressure loss increases as PM is collected. In addition, since PM concentrates and accumulates in the vicinity of the clogging portion of the inflow side cell, there is a problem that exhaust pressure loss increases at a stretch. When importance is attached to engine efficiency or fuel consumption, it is necessary to frequently perform regeneration processing.

  On the other hand, in German utility model 20,117,873 U1, a corrugated plate made of metal foil and a filter layer are alternately laminated to form a plurality of claw-shaped holes having claw-shaped hole heights on the corrugated plate. The inner hole forms a flow path having an inward nail hole and an outward nail hole, the inward nail hole and the outward nail hole are arranged at an angle with each other, and the nail hole height is equal to the structural height. A filter is described which is 100-60% high and guarantees a flow freedom of at least 20%.

According to this filter, PM is collected in the filter layer by the exhaust gas coming out of the claw-shaped holes passing through the filter layer. However, in this filter device, if PM deposits on the filter layer and the claw portion of the claw-shaped hole, the exhaust gas flow path is blocked and the exhaust pressure loss increases rapidly, so the amount of PM that can be collected is increased. However, there is a disadvantage that the PM collection efficiency must be lowered.
JP 09-262414 A JP 2002-113798 German utility model 20,117,873 U1

  In view of this, the inventors of the present application disclosed in Japanese Patent Application No. 2004-117189, an exhaust gas purification filter device having a plurality of exhaust gas passages and filters installed in the exhaust gas passages. Has proposed an exhaust gas purification filter device having a filter introduction part that leads to the exhaust gas flow path adjacent to the filter introduction part and a filter bypass part that bypasses the filter introduction part.

  However, when various experiments were conducted for practical use, in the exhaust gas purification filter device described above, when exhaust gas containing high concentration PM flows in for a long time depending on operating conditions, there is a large amount of PM on the inflow side end face of the filter device. It became clear that it might accumulate. When a large amount of PM accumulates on the inflow side end face in this way, exhaust pressure loss increases, and when ignited under high-temperature conditions, the filter as a whole will rapidly increase in temperature even if it is less than the allowable limit amount. However, there are concerns that failures such as melting may occur.

  The present invention has been made in view of such circumstances, and it is an object to achieve both improvement in PM collection efficiency and suppression of increase in exhaust pressure loss, and suppression of PM accumulation on the inflow side end face. And

A feature of the exhaust gas purification filter device of the present invention that solves the above problems is an exhaust gas purification filter device having a plurality of exhaust gas flow channels and a filter installed in the exhaust gas flow channel,
The exhaust gas flow path has a filter introduction part that guides the exhaust gas to the filter, and a filter bypass part that branches to the exhaust gas flow path adjacent to the filter introduction part and bypasses the filter introduction part,
The most upstream filter bypassing part is provided upstream of the most upstream filter introducing part and is open to the exhaust gas inlet side end face.

A feature of the exhaust gas purification filter device that further embodies this exhaust gas purification filter device is that a corrugated plate made of a thin metal plate and alternately continuous in a direction intersecting the exhaust gas flow direction and heat resistant fibers are integrated. And gas permeable flat plates constituting the filter are alternately laminated,
The ridge has a concave middle valley that is formed by lowering the mountain height, and the middle valley communicates with the ridge at the downstream side where the exhaust gas diverges and flows from the adjacent valley. A filter detour that consists of an opening and
The trough has a convex intermediate peak formed by the shallow valley depth, and the filter is introduced with the channel blocked by the peak on both sides adjacent to the intermediate peak and the flat plate in contact with the peak. Part
When the pressure in the filter inlet increases, at least a part of the exhaust gas flowing in the valley flows from the filter inlet to the adjacent peak by passing through the filter bypass located upstream of the filter inlet. Upstream, the exhaust gas is first configured to flow into the most upstream filter bypass.

In addition, if the characteristics of the exhaust gas purification filter device are expressed from the back side of the corrugated plate, the corrugated plate made of a thin metal plate and alternately continuous in the direction in which the crests and troughs intersect the exhaust gas flow direction, and the heat-resistant fiber Gas-permeable flat plates that are integrated and constitute a filter are alternately laminated,
The valley portion has a convex intermediate mountain portion formed by decreasing the valley depth, and the intermediate mountain portion is a branch portion where exhaust gas can branch from the adjacent mountain portion and can flow in, and a valley portion on the downstream side thereof. A filter bypass portion comprising an opening communicating with the
The peak portion has a concave intermediate valley portion formed by lowering the peak height, and the filter introduction portion in which the flow path is blocked by the valley portion on both sides adjacent to the intermediate valley portion and the flat plate in contact with the valley portion. Configure
When the pressure in the filter inlet increases, at least a part of the exhaust gas flowing through the peak flows from the filter inlet through the filter bypass located upstream of the filter inlet and flows into the adjacent valley. Upstream, the exhaust gas is first configured to flow into the most upstream filter bypass.

  The most upstream filter detour includes a crest having an upstream opening and a downstream opening, a trough that continues to the downstream opening, and a reverse that continues to the crest on the downstream side as the depth of the trough gradually decreases. And an intermediate valley portion.

  The most upstream filter detour part is a valley part and an inverted intermediate mountain part that is formed in the valley part and opens to the upstream end part and gradually decreases in height toward the downstream side and continues to the downstream valley part. It can also be made up of.

  Further, the most upstream filter bypass portion may be a through-hole through which PM in the exhaust gas can be formed, which is formed at a position facing a crest of the flat plate laminated on the lower side of the corrugated plate, or the lower side of the corrugated plate It is good also as a notch part which can permeate | transmit PM in the waste gas formed in the position facing the peak part of the flat plate laminated | stacked by.

  According to the exhaust gas purifying filter device of the present invention, when PM accumulates in the filter introduction part and the exhaust pressure loss increases, the exhaust gas branches off from the filter bypass part and flows through the filter bypass part sequentially. However, since it flows to the outflow side end, an increase in exhaust pressure loss is suppressed.

  And since the filter from a filter introduction part to a filter detour part can be used for collection of PM, and the big area of a filter can be used for collection of PM, PM can be collected efficiently. Moreover, when oxidizing the collected PM, the oxidizing agent and heat are efficiently transmitted to the PM, so that the collected PM can be efficiently oxidized.

  Furthermore, since the exhaust gas first passes through the most upstream filter detour part, PM accumulation on the inflow side end face can be suppressed, and end face obstruction is unlikely to occur. Therefore, it is possible to always ensure a large flow path opening on the inflow side end face, to suppress an increase in exhaust pressure loss, and to avoid a melting loss due to excessive temperature rise. In addition, although the PM collection efficiency is microscopically reduced, the entire exhaust gas flow path always functions effectively, so the overall collection efficiency can be maintained high, and rather the PM collection efficiency is improved. It also comes to do.

  The exhaust gas purification filter device of the present invention has a plurality of exhaust gas flow paths and a filter installed in the exhaust gas flow path, and the exhaust gas flow path is adjacent to the filter introduction part that guides the exhaust gas to the filter, and the filter introduction part And a filter bypass section that branches to the exhaust gas flow path that bypasses the filter introduction section.

  The filter can collect PM and has air permeability, and ceramics, metal fiber aggregates, and the like can be used. By arranging this filter in the exhaust gas flow path, a filter introduction part can be formed, and by bypassing the filter by forming a through hole etc. communicating with the adjacent exhaust gas flow path in the exhaust gas flow path on the upstream side thereof The part can be formed. As a particularly preferred embodiment, it is desirable to make a honeycomb-shaped filter device in which corrugated plates having no air permeability and flat plate filters are alternately laminated.

  As such a filter apparatus, the thing of Claim 2 or Claim 3 is especially preferable. In the exhaust gas purifying filter device according to claim 2, the exhaust gas flowing into the flow path formed by the valley portion and the upper flat plate passes through the upper flat plate that collides with the intermediate mountain portion and partitions the filter introduction portion, PM is collected on the flat plate. When the amount of PM trapped on the upper flat plate that partitions the filter introduction portion increases, the pressure in the filter introduction portion increases, so the exhaust gas passes through the branch portion of the filter detour portion on the upstream side from the filter introduction portion, and the peaks on both sides Branch inflows from the middle valley to the peaks on both sides.

  And as described in claim 3, on the back side of the corrugated plate, the back side of the intermediate valley is convex and a filter introduction part is formed between the peak and the lower flat plate, and the upstream valley Since the filter detour part is formed at the intermediate peak of the exhaust gas, the exhaust gas flowing into the flow path formed by the peak and the lower flat plate collides with the intermediate valley and the pressure increases in the filter introduction part From the filter introduction part, it passes through the filter detour part on the upstream side, and branches and flows into the troughs on both sides through the opening of the intermediate peak part of the troughs on both sides.

  This action is continuously repeated from the exhaust gas inflow side end surface to the outflow side end surface.

  That is, since the filter device of the present invention basically has a wall flow structure, the PM collection efficiency is high. Even if the amount of PM trapped on the flat plate in the filter introduction portion increases, the exhaust gas branches off from the upstream filter detour portion and flows into the peak portion or valley portion, which continuously occurs. Therefore, an increase in exhaust pressure loss due to PM accumulation does not occur all at once, and since most of the flat plate can be used for PM collection, an increase in exhaust pressure loss can be effectively suppressed.

  Further, the most upstream filter bypass portion is provided on the upstream side of the most upstream filter introduction portion and is open to the exhaust gas inlet side end surface. Therefore, in the uppermost stream, the exhaust gas first flows into the uppermost filter detour part, so that PM accumulation on the inflow side end face can be suppressed and end face blockage hardly occurs.

  The corrugated plate is formed from a thin metal plate, and is preferably manufactured by corrugating or the like. The material is not particularly limited as long as it has heat resistance that can withstand the exhaust gas temperature and heat during regeneration, but a stainless steel material is preferable. For automobiles, the thickness is preferably in the range of 20 to 110 μm, particularly preferably in the range of 40 to 80 μm.

  The flat plate is a gas-permeable member in which heat-resistant fibers are integrated, and can be formed from non-woven fabrics such as metal fibers, ceramic fibers, metal whiskers, and ceramic whiskers, and woven fabrics. In order to achieve both improvement in PM collection efficiency and suppression of increase in exhaust pressure loss as an exhaust gas purification filter device for automobiles, the fiber diameter is preferably about 15 to 60 μm, and the basis weight is preferably 300 to 1000 g / m 2.

  In order to obtain the filter device of the present invention, the corrugated plates and the flat plates may be alternately stacked and inserted into a predetermined outer cylinder, or the corrugated plates and the flat plates of a predetermined length may be overlapped and wound into a roll shape. This can be inserted into a predetermined outer cylinder. Note that the corrugated plates may be laminated so that all layers have the same direction and the same phase, or can be laminated so that the directions are alternately different by 180 degrees or the phases are different. However, when the filter introduction part is formed in the valley part, it is desirable that there is a crest of the adjacent corrugated plate on the opposite side through the flat plate, and the filter introduction part is formed in the crest part. If there is, it is desirable that a trough portion of the adjacent corrugated plate exists on the opposite side through the flat plate. As a result, the PM collection efficiency can be further improved and the increase in exhaust pressure loss can be further suppressed without impeding the flow of the exhaust gas that has permeated the flat plate.

  The intermediate valley portion or the intermediate mountain portion is formed by deforming the mountain portion or the valley portion, and it is desirable that the upstream end portion is smoothly continuous toward the bottom portion or the top portion, respectively. That is, it is preferable that the height is gradually reduced toward the upstream side, or is blocked by a slope that becomes higher. By doing in this way, since the vector which goes to the flat plate which partitions a filter introduction part produces | generates in the exhaust gas in a filter introduction part, PM collection efficiency improves further.

  The opening area of the corrugated plate in plan view in the filter introduction part is desirably 30% or more of the total opening area of the corrugated plate in plan view. When the opening area of the corrugated plate in plan view at the filter introduction portion is less than 30% of the total opening area, the use area of the flat plate is reduced and the PM collection efficiency is reduced. The total volume of the filter introduction part is preferably 50% or more of the total volume of the peak part and the valley part. When this ratio is less than 50%, the PM collection efficiency decreases.

  Also, the longer the distance from the filter introduction part to the upstream branch part, the better the PM collection efficiency, but the exhaust pressure loss tends to increase. Therefore, there is an optimum value for the distance.

  The most upstream filter detour includes a crest having an upstream opening and a downstream opening, a trough that continues to the downstream opening, and a reverse that continues to the crest on the downstream side as the depth of the trough gradually decreases. And an intermediate valley portion. In this case, the exhaust gas first flows into the peak from the upstream end face, and the exhaust gas that has exited from the peak flows into the reverse intermediate valley from the valley. Since the reverse intermediate valley portion is continuous with the peak portion on the downstream side, the tip portion is closed with a flat plate. However, even if PM accumulates in that part, there is a gap between the flat plate up to the middle of the reverse intermediate valley, and the exhaust gas branches and flows into the valley on both sides from the gap. The trough functions as a filter bypass.

  The most upstream filter detour part is a valley part and an inverted intermediate mountain part that is formed in the valley part and opens to the upstream end part and gradually decreases in height toward the downstream side and continues to the downstream valley part. It is good also as what consists of. In this case, the exhaust gas first flows into the valley from the upstream end face, and then flows into the reverse intermediate peak. Since the inverted intermediate mountain part has a ceiling part that is continuous with the valley part on the downstream side, the tip part is closed with a flat plate on the back side. However, even if PM accumulates in that part, there is a gap between the flat plate up to the middle of the reverse intermediate peak, and the exhaust gas branches and flows from the gap to the peaks on both sides. The peak functions as a filter bypass.

  Further, the most upstream filter bypass portion may be a through-hole through which PM in the exhaust gas can be formed, which is formed at a position facing a crest of the flat plate laminated on the lower side of the corrugated plate, or the lower side of the corrugated plate It is good also as a notch part formed in the position facing the peak part of the flat plate laminated | stacked by. In this case, even if the exhaust gas first flows into the peak and PM accumulates in the filter introduction part on the downstream side, it passes through the through hole or notch and enters the exhaust gas flow path of the corrugated plate stacked on the lower side through the flat plate. Since it flows in, the through hole and the notch function as a filter bypass.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Comparative Example 1)
FIG. 1 is a perspective view and an enlarged view of a main part of the filter device of this comparative example, FIG. 2 is an essential part perspective view of a corrugated plate, and FIGS. This filter device is made of a corrugated plate made of stainless steel and having a thickness of 65 μm, and a flat plate 3 made of stainless steel fiber mat and having a basis weight of 450 g / m 2 and a thickness of 300 μm. And the outer cylinder 4 in which the filter element is press-fitted and held.

  In the corrugated plate 1 shown in FIG. 2, the crests 10 and the troughs 11 are alternately continued in a direction orthogonal to the exhaust gas flow direction. In the peak portion 10, a plurality of concave intermediate valley portions 12 are formed in parallel to the exhaust gas flow direction and spaced from each other. The intermediate valley portion 12 gradually decreases in height from the upstream side to the downstream side of the exhaust gas, and the tip thereof is cut away to form an opening 13 communicating with the mountain portion 10 again. The depth of the bottom of the intermediate valley 12 is the same as the position of the bottom of the valley 11.

  In the valley portion 11, a plurality of convex intermediate mountain portions 14 are formed in parallel to the exhaust gas flow direction and spaced from each other. The intermediate mountain portion 14 is disposed between the two intermediate valley portions 12 in the exhaust gas flow direction, and the height thereof is the same as the height of the mountain portion 10.

  As shown in FIG. 3, the plurality of corrugated plates 1 are alternately laminated with the flat plate 3 so that the phases of the intermediate valley portions 12 and the intermediate mountain portions 14 are the same in the exhaust gas flow direction and in the direction perpendicular to the exhaust gas flow direction. The intermediate valley portion 12 and the intermediate mountain portion 14 are arranged at the same position in the cross section cut at right angles to the exhaust gas flow direction of the filter element. Further, the peak portion 10 is in contact with the upper flat plate 3, and the valley portion 11 is in contact with the lower flat plate 3.

  In this filter device, as shown in FIGS. 4 to 7, on the surface side of the corrugated plate 1, most of the flow path is blocked by the peak portions 10 on both sides adjacent to the intermediate peak portion 14 and the upper flat plate 3. A filter introduction part 100 is formed. Further, on the back side of the corrugated plate 1, a filter introduction portion 101 is formed in which most of the flow path is closed by the valley portions 11 on both sides adjacent to the intermediate valley portion 12 and the lower flat plate 3. Further, on the upstream side of the filter introduction part 100, the height of the peak part 10 is lowered at the position of the intermediate valley part 12, and the opening 13 is formed, so that the exhaust gas flowing through the valley part 11 flows from the opening 13 on both sides to the both sides. A branch can flow into the mountain portion 10, and a filter bypass portion 200 is formed there. In addition, on the back side, the depth of the valley portion 11 becomes shallow and the opening 15 is formed at the position of the intermediate peak portion 14 on the upstream side of the filter introduction portion 101. Can flow into the troughs 11 on both sides, and the filter bypassing part 201 is also formed there.

  And as shown in FIG. 4, the exhaust gas which flows through the flow path formed between the trough part 11 and the upper flat plate 3 collides with the intermediate mountain part 14, and the amount of PM trapped on the upper flat plate 3 is small. Then, most of the exhaust gas passes through the upper flat plate 3 and flows into the trough 11 of the corrugated plate 1 existing on the opposite side of the flat plate 3, and most of PM is collected by the flat plate 3.

  When the amount of collected PM increases and the pressure of the exhaust gas at the filter introduction part 100 increases, the exhaust gas does not easily pass through the flat plate 3 of the filter introduction part 100 as shown in FIG. In the existing filter bypass part 200, it branches from the intermediate valley part 12 through the opening 13 and flows into the adjacent peak part 10. Therefore, an increase in exhaust pressure loss is suppressed.

  Similarly, the exhaust gas flowing through the flow path formed between the peak portion 10 and the lower flat plate 3 collides with the intermediate valley portion 12 in the filter introduction portion 101 as shown in FIG. In a state where the collected amount is small, most of the exhaust gas passes through the lower flat plate 3 and flows into the trough portion 11 of the corrugated plate 1 on the opposite side of the flat plate 3. It is collected at.

  When the amount of collected PM increases and the pressure of the exhaust gas at the filter introduction part 101 increases, the exhaust gas becomes difficult to pass through the flat plate 3 of the filter introduction part 100 as shown in FIG. The filter bypass portion 201 located on the side passes through the opening 15 from the intermediate peak portion 14 and branches into the adjacent valley portion 11. Therefore, an increase in exhaust pressure loss is suppressed.

  According to the filter device of this comparative example, PM is collected on the flat plate 3 in the filter introduction units 100 and 101 by continuously repeating the above-described cycle from the exhaust gas inflow side end surface toward the outflow side end surface. Since a large number of filter introduction parts 100 and 101 are formed, PM is uniformly dispersed and collected over the entire flat plate 3, and the collection efficiency is improved and PM is collected. Exhaust pressure loss is unlikely to rise. That is, the improvement of the PM collection efficiency and the suppression of the increase of the exhaust pressure loss are compatible.

Example 1
The filter device of this example has the same structure as that of Comparative Example 1 except that the structure of the corrugated plate at the end portion on the exhaust gas inflow side is different. In the filter device of the present embodiment, as shown in FIGS. 8 and 9, the exhaust gas inflow side end face is formed with a peak portion 10 having an opening cut out on the downstream side, and the valley is continuously formed on the downstream side opening. Part 11 is formed. In this valley portion 11, an inverted intermediate valley portion 16 having a gradually shallower depth is formed. The inverted intermediate valley portion 16 is continuous with the downstream peak portion 10, and the upstreammost filter bypassing portion 202 is formed in this portion. Is formed.

  That is, in the filter device of this embodiment, as indicated by arrows in FIG. 9, the exhaust gas first flows into the peak portion 10 from the upstream end face, and the exhaust gas that has exited from the peak portion 10 passes from the valley portion 11 to the reverse intermediate valley portion 16. Inflow. Since the reverse intermediate valley portion 16 is continuous with the peak portion 10 on the downstream side, the top surface of the tip end portion is covered with the flat plate 3. However, even if PM accumulates in that portion, there is a gap with the flat plate 3 up to the middle of the reverse intermediate valley portion 16, and the exhaust gas branches and flows into the valley portions 11 on both sides from the gap.

  Therefore, since the filter detour portion 202 is formed in the most upstream, PM accumulation on the exhaust gas inflow side end surface is suppressed, end surface blockage is prevented, and melting damage due to excessive temperature rise can be avoided.

(Example 2)
The filter device of the present embodiment has the same structure as that of the comparative example 1 except that the structure of the corrugated plate 1 at the exhaust gas inflow side end is different. In the filter device of the present embodiment, as shown in FIG. 10, a trough 11 is formed on the exhaust gas inflow side end surface, and the trough 11 is formed in the trough 11 and opens upstream, and the height gradually decreases toward the downstream. An inverted intermediate mountain 17 that is continuous with the valley 11 on the downstream side is formed, and the most upstream filter bypass 202 is formed in this portion.

  That is, in the filter device of the present embodiment, as indicated by arrows in FIG. 10, the exhaust gas first flows into the valley portion 11 from the upstream end face, and then flows into the reverse intermediate mountain portion 17. Since the reverse intermediate mountain portion 17 gradually decreases in height and continues to the valley portion 11 on the downstream side, the lower surface of the tip portion is closed by the flat plate 3 on the back surface side. However, even if PM accumulates in that portion, there is a gap with the flat plate 3 up to the middle of the reverse intermediate peak portion 17, and the exhaust gas branches into the peak portions 10 on both sides and flows in from the gap.

  Therefore, since the filter detour portion 202 is formed in the most upstream, PM accumulation on the exhaust gas inflow side end surface is suppressed, end surface blockage is prevented, and melting damage due to excessive temperature rise can be avoided.

(Example 3)
The filter device of the present embodiment shown in FIG. 11 has the same structure as that of Comparative Example 1 except that the structure of the flat plate 3 at the exhaust gas inflow side end is different. Only the exhaust gas inflow side end of the flat plate 3 is formed from a metal plate 30, and a plurality of through holes 31 having a hole diameter of several mm are formed in the metal plate 30.

  That is, in the filter device of the present embodiment, since the through hole 31 is formed on the upstream side of the filter introduction part 100, the exhaust gas flowing into the peak part 10 passes through the through hole 31 together with PM and is laminated on the back side. It flows into the next corrugated plate 1. Therefore, since the filter detour portion 202 is formed in the most upstream, PM accumulation on the exhaust gas inflow side end surface is suppressed, end surface blockage is prevented, and melting damage due to excessive temperature rise can be avoided.

Example 4
The filter device of the present embodiment shown in FIG. 12 has the same structure as that of Comparative Example 1 except that the structure of the flat plate 3 at the exhaust gas inflow side end is different. The length of the flat plate 3 in the exhaust gas flow direction is shorter than that of the corrugated plate 1, and the flat plate 3 does not exist below the peak portion 10 at the exhaust gas inflow side end of the corrugated plate 1.

  That is, in the filter device of this embodiment, since the flat plate 3 does not exist on the upstream side of the filter introduction unit 100, the exhaust gas flowing into the peak portion 10 flows into the next corrugated plate 1 laminated on the back side together with PM. Therefore, since the filter detour portion 202 is formed in the most upstream, PM accumulation on the exhaust gas inflow side end surface is suppressed, end surface blockage is prevented, and melting damage due to excessive temperature rise can be avoided.

(Comparative Example 2)
The filter device described in Example 1 of German utility model 20,117,873 U1 was used as Comparative Example 2.

  That is, the filter device of Comparative Example 2 uses the same corrugated plate 1 as in Comparative Example 1, and is alternately laminated with the same flat plate 3 as in Comparative Example 1, but the exhaust gas inlet side in Comparative Example 1 is on the outlet side, It is inverted 180 degrees so that the exit side becomes the entrance side.

<Test and evaluation>
Using the filter devices of Examples 1 to 4 and Comparative Examples 1 and 2, the PM collection rate, the exhaust pressure loss, and the front end face blocking rate were measured. The filter elements are about 1 L each having a diameter of 130 mm and a length of 75 mm, and the number of cells per square inch of the cross section is 200 cells.

  The filter devices of the example and the comparative example were respectively mounted on the exhaust pipe of a diesel engine, and a 1.3 L oxidation catalyst was disposed upstream thereof. Then, in the 2L engine, which is a condition for discharging high concentration PM, UDC pseudo mode, it was operated for 10 hours in the EGR fully open state, and the ratio of the cell opening on the front end face of the filter being blocked with PM was visually measured. . Further, the PM collection rate and the exhaust pressure loss were measured when the PM accumulation amount became 1 g / L during steady running (2 L engine, 2400 rpm, 50 Nm, PM emission amount 3 g / hr). The results are shown in Table 1. Note that PM here means soot.

  From Table 1, it can be seen that the filter devices of Examples 1 to 4 have a lower front end face blocking rate than the filter device of Comparative Example 1, and this is the effect of forming the filter bypass portion 202 in the uppermost stream. It is. Moreover, it turns out that the filter apparatus of Examples 1-4 has high PM collection efficiency compared with the filter apparatus of the comparative example 2, and the raise of exhaust pressure loss is also suppressed largely, These differences are the structures of the corrugated board 1 It is also clear that this is due to the difference.

  The exhaust gas purification filter device of the present invention may be used as it is, or may be a filter catalyst in which a catalyst metal such as Pt is supported on at least a part of the corrugated plate and the flat plate. The catalyst metal may be directly supported on at least a part of the corrugated plate and the flat plate, or a coating layer made of a porous oxide may be formed and supported on the coating layer. By setting it as such a filter catalyst, oxidation combustion can be promoted simultaneously with PM collection. Moreover, it becomes possible to purify harmful gas components such as HC and CO in the exhaust gas by the catalytic metal.

It is the perspective view of the filter apparatus of the comparative example 1, and the principal part expansion perspective view. 5 is a perspective view of a main part of a corrugated plate used in the filter device of Comparative Example 1. FIG. 6 is an enlarged cross-sectional view of a main part of a filter device of Comparative Example 1. FIG. 6 is an enlarged cross-sectional view of a main part of a filter device of Comparative Example 1. FIG. 6 is an enlarged cross-sectional view of a main part of a filter device of Comparative Example 1. FIG. 6 is an enlarged cross-sectional view of a main part of a filter device of Comparative Example 1. FIG. 6 is an enlarged cross-sectional view of a main part of a filter device of Comparative Example 1. FIG. It is the perspective view of the filter apparatus of Example 1, and the principal part expansion perspective view. It is a principal part perspective view of the corrugated board used for the filter apparatus of Example 1. FIG. It is a principal part perspective view of the corrugated board used for the filter apparatus of Example 2. FIG. It is a principal part perspective view of the filter apparatus of Example 3. FIG. It is a principal part perspective view of the filter apparatus of Example 4.

Explanation of symbols

1: Corrugated plate 3: Flat plate 4: Outer tube 10: Mountain
11: Valley 12: Middle valley 13: Opening 14: Middle mountain
15: Opening 16: Reverse intermediate valley 17: Reverse intermediate mountain
100, 101: Filter introduction part 200, 201, 202: Filter bypass part

Claims (7)

An exhaust gas purification filter device having a plurality of exhaust gas passages and a filter installed in the exhaust gas passages,
The exhaust gas flow path has a filter introduction part that guides the exhaust gas to the filter, and a filter bypass part that branches to the exhaust gas flow path adjacent to the filter introduction part and bypasses the filter introduction part,
The exhaust gas purification filter device, wherein the most upstream filter bypassing portion is provided upstream of the upstreammost filter introduction portion and is open to an end surface on the exhaust gas inlet side. A corrugated plate made of a thin metal plate and having alternating peaks and valleys alternately in the direction intersecting the exhaust gas flow direction, and gas permeable flat plates constituting heat-resistant fibers and constituting the filter alternately. Laminated,
The peak portion has a concave middle valley portion formed by lowering the mountain height, and the middle valley portion has a branch portion where exhaust gas can branch from the adjacent valley portion and can flow in, and downstream of the branch portion. Constructing the filter detour part comprising an opening communicating with the mountain part,
The valley portion has a convex intermediate peak portion formed by decreasing the depth of the valley, and the flow path is formed by the peak portions on both sides adjacent to the intermediate peak portion and the flat plate in contact with the peak portion. Constituting the blocked filter introduction part,
When the pressure in the filter introduction part increases, at least a part of the exhaust gas flowing through the valley part passes through the filter bypass part existing upstream from the filter introduction part and is adjacent to the mountain. The exhaust gas purifying filter device according to claim 1, wherein the exhaust gas purifying filter device is configured to flow into the first part and to flow into the filter detour part at the uppermost stream first. A corrugated plate made of a thin metal plate, with ridges and valleys alternately arranged in the direction intersecting the exhaust gas flow direction, and gas-permeable flat plates that constitute a filter made up of heat-resistant fibers are laminated alternately. Being
The valley portion has a convex intermediate mountain portion formed by a shallow valley depth, and the intermediate mountain portion is a branched portion where exhaust gas can branch from the adjacent mountain portion and can flow in, and the downstream side thereof. And a filter bypass portion composed of an opening communicating with the valley portion.
The peak portion has a concave intermediate valley portion formed by decreasing the peak height, and the flow path is blocked by the valley portion on both sides adjacent to the intermediate valley portion and the flat plate in contact with the valley portion. The filter introduction part,
When the pressure in the filter introduction part increases, at least part of the exhaust gas flowing through the peak part passes through the filter bypass part existing on the upstream side of the filter introduction part from the filter introduction part and is adjacent to the valley. The exhaust gas purifying filter device according to claim 1, wherein the exhaust gas purifying filter device is configured to flow into the first part and to flow into the filter detour part at the uppermost stream first.   The most upstream filter bypass portion includes the crest portion having an upstream opening and a downstream opening, the trough portion continuous to the downstream opening, and the depth of the trough portion gradually becoming shallower, The exhaust gas purification filter device according to claim 2 or 3, further comprising an inverted intermediate valley portion that is continuous with the mountain portion.   The most upstream filter bypass portion is formed in the valley and the reverse formed in the valley and opening at the upstream end and gradually lowering toward the downstream and continuing to the valley on the downstream side. The exhaust gas purification filter device according to claim 2 or 3, comprising an intermediate mountain portion.   The uppermost filter bypass portion is a through-hole through which particulate matter in the exhaust gas is formed at a position facing the peak portion of the flat plate stacked below the corrugated plate. Or the exhaust gas purification filter apparatus of Claim 3.   The uppermost filter bypass portion is a cutout portion through which particulate matter in the exhaust gas can be transmitted, which is formed at a position facing the crest portion of the flat plate stacked below the corrugated plate. The exhaust gas purification filter device according to claim 2 or claim 3.

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