JP6627479B2 - Exhaust gas purification device - Google Patents

Description

  The present invention relates to an exhaust purification device provided with a selective reduction catalyst.

A selective reduction catalyst (hereinafter, referred to as "SCR catalyst") is provided in an exhaust passage for purifying nitrogen oxides (hereinafter, referred to as "NOx") in lean exhaust discharged from a diesel engine which is an internal combustion engine. Exhaust gas purifying devices are known. SCR catalyst, than the catalyst is hydrolyzed urea water supplied into the exhaust passage from the exhaust upstream over a catalyst to form ammonia (NH ₃₎ and, NOx in lean atmosphere exhaust by the ammonia (NH ₃₎ Is selectively reduced and purified. When such an SCR catalyst is used, urea water is injected into the exhaust passage from a urea water supply unit disposed on the exhaust upstream side of the SCR catalyst, and a dispersion member disposed between the urea water supply means and the SCR catalyst is used. Urea water is dispersed using the urea water to promote mixing and atomization with exhaust gas due to vaporization by exhaust heat and supply the SCR catalyst to the SCR catalyst (for example, Patent Document 1).

JP 2014-202099 A

Some urea water injected into the exhaust passage is dispersed by the dispersing member, while others are not dispersed and adhere to the exhaust passage and are not supplied to the SCR catalyst.
An object of the present invention is to make it possible to efficiently supply urea water injected into an exhaust passage to a selective reduction catalyst.

An exhaust gas purification apparatus according to the present invention includes a urea water supply unit that supplies urea water into an exhaust passage through which exhaust gas discharged from an internal combustion engine flows, and a urea water supply unit that is disposed downstream of the urea water supply unit. A selective reduction catalyst for selectively reducing nitrogen oxides contained in exhaust gas using urea water supplied from the urea water as a reducing agent; and a urea water supply unit disposed in an exhaust passage between the urea water supply unit and the selective reduction catalyst. exhaust is disposed in the passage, an exhaust passage of resupplying the urea water resupply member in said exhaust urea water in a liquid state at between the dispersion member, the selective reduction catalyst and the dispersion member for dispersing the injected urea water from A contact portion attached to the inner surface of the exhaust passage so as to have a gap with the inner surface, an inclined portion inclined from the contact portion toward the center of the exhaust passage. The inclined portion has a cut in the inclined portion , Or it is characterized by urea ascender raising the urea water by providing a hole.

  According to the present invention, the liquid urea water in the exhaust passage is raised toward the center direction of the exhaust passage by the urea water re-supply member disposed between the dispersion member and the selective reduction catalyst. Since it is vaporized by the heat of the exhaust gas and mixed into the exhaust gas, the urea water injected into the exhaust passage can be efficiently supplied to the selective reduction catalyst.

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of an exhaust gas purification device according to the present invention. It is a figure explaining composition of a urea water re-supply member with which an exhaust gas purification device is provided, (a) is a top view and (b) is a side view. FIG. 4 is an enlarged cross-sectional view showing a rising state of liquid urea water by a urea water re-supply member. It is a figure which shows the urea water re-supply member formed by joining several plate-shaped members, (a) is a top view, (b) is sectional drawing. The top view which shows the structure of the urea water re-supply member provided with the urea rising part with which the density in the part which urea water tends to accumulate easily was raised. The top view which shows the structure of the urea water re-supply member provided with the urea rising part with which the density in the site | part which urea water easily accumulates was reduced. The figure which shows the schematic structure of 2nd Embodiment of the exhaust gas purification device which concerns on this invention which changed the arrangement | positioning position of the urea water re-supply member. The figure which shows schematic structure of 3rd Embodiment of the exhaust gas purification device which concerns on this invention provided with the several urea-water re-supply member. The figure which shows the list of several modification of a urea water re-supply member. (A), (b) is an enlarged view which shows the mounting structure of the urea water re-supply member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in consideration of legibility of the drawings, constituent elements may be partially omitted or broken.
The exhaust gas purification device 30 according to the present embodiment is applied to a multi-cylinder diesel engine (hereinafter referred to as “engine”) 1 that is an internal combustion engine mounted on a vehicle. FIG. 1 shows one of a plurality of cylinders 2 provided in the engine 1, but the other cylinders 2 have the same configuration. In the cylinder 2 of the engine 1, a piston 3 having a cavity formed on a top surface is disposed in the cylinder 2 so as to reciprocate vertically.

  An in-cylinder injection valve 4 which is an injector for fuel injection is provided in a cylinder head located above the cylinder 2. High-pressure fuel adjusted to a predetermined fuel pressure by a common rail is supplied to the in-cylinder injection valve 4. This fuel is light oil, which is a mixture of hydrocarbons (HC). The in-cylinder injection valve 4 is provided with its tip protruding into the in-cylinder space of the cylinder 2 and injects high-pressure fuel into the in-cylinder space.

  The cylinder head is provided with an intake port 5 and an exhaust port 6 communicating with the in-cylinder space of the cylinder 2, and an intake valve 7 and an exhaust valve 8 for opening and closing the intake port 5 and the exhaust port 6. An intake manifold (hereinafter, referred to as “in manifold”) 9 is connected to the intake upstream side of the intake port 5. An intake passage 12 is connected to an intake upstream end of the intake manifold 9. An electronically controlled throttle valve 11 is provided in the intake passage 12. The amount of air flowing to the intake manifold 9 is adjusted according to the opening of the throttle valve 11 (throttle opening). An air filter 13 is provided at the uppermost stream of the intake passage 12, and fresh air (air) filtered by the air filter 13 is introduced into the intake passage 12.

  An exhaust manifold (hereinafter, referred to as “exhaust manifold”) 15 formed so as to join from the plurality of cylinders 2 is connected to the exhaust downstream side of the exhaust port 6. An exhaust passage 16 through which the exhaust G indicated by the white arrow discharged from the engine 1 flows is connected to the exhaust downstream of the exhaust manifold 15. An exhaust purification device 30 is provided in the exhaust passage 16. The exhaust gas G flowing through the exhaust passage 16 is purified by the exhaust gas purification device 30 and then discharged out of the vehicle via a muffler (not shown).

The exhaust purification device 30 according to the present embodiment includes a urea SCR (Selective Catalytic Reduction) system 40. The urea SCR system 40 includes a urea water injection valve 41 as a urea water supply unit, an SCR catalyst 42 as a selective reduction catalyst, a urea water tank 45 for storing urea water 46 to be injected from the urea water injection valve 41 in a liquid state, A mixer 47 as a dispersion member and a urea water re-supply member 48 are provided.
The urea water injection valve 41 is configured to inject urea water 46 as a reducing agent (additive) from its tip nozzle and supply the urea water 46 to the exhaust gas in the exhaust passage 16 in the form of a spray. A urea water tank 45 storing urea water 46 is connected to the urea water injection valve 41 via a supply line 43. The urea water tank 45 is provided with a urea water pump 44, and the urea water pump 44 is driven to supply urea water 46 to the urea water injection valve 41.

The SCR catalyst 42 is a well-known one for reducing NOx, which is a nitrogen oxide contained in the exhaust gas G, by using ammonia (NH ₃ ) generated from the urea water 46. The SCR catalyst 42 is a well-known one in which vanadium, molybdenum, tungsten, zeolite, or a noble metal is adhered as an active catalyst component to a carrier having a honeycomb structure formed of ceramics, titanium oxide, or the like. In the SCR catalyst 42, the urea water 46 injected from the urea water injection valve 41 into the exhaust passage 16A and diffused by the mixer 47 is hydrolyzed and thermally decomposed by the heat of the exhaust gas (CO (NH ₂ ) ₂ → NH). ₃ + HOCN, HOCN + H ₂ O → NH ₃ + CO ₂ ), and ammonia (NH ₃ ) generated as a reducing agent. The SCR catalyst 42 reacts with NOx in the exhaust gas on the catalyst, and reduces (purifies) NOx to nitrogen (N ₂ ) and water (H ₂ O).

  The mixer 47 is disposed in the exhaust passage 16A between the urea water injection valve 41 and the SCR catalyst 42. The mixer 47 receives the urea water 46 injected from the urea water injection valve 41 and radially disperses the urea water 46 toward the inner surface 16Aa of the exhaust passage 16.

The urea water 46 sprayed from the urea water injection valve 41 into the exhaust passage 16 is diffused by the mixer 47 to promote atomization, evaporate in the exhaust gas and mix as vapor and fine particles. Then, it is evenly flowed into the SCR catalyst 42 and comes into contact with the SCR catalyst 42 to be used for NOx reduction. All of the urea water 46 sprayed from the urea water injection valve 41 into the exhaust passage 16A is not only transported to the SCR catalyst 42, but also becomes vaporized by spray attached to the inner surface 16Aa of the exhaust passage 16A. Some of them become liquid without being separated, and others become liquid without being completely dispersed and attached to the mixer 47, and are collected in the liquid in the exhaust passage 16. That is, the urea water 46 injected from the urea water injection valve 41 is not supplied to the SCR catalyst 42 in some cases.
Therefore, reusing the liquid urea water 46 as a reducing agent allows the urea water 46 injected into the exhaust passage 16A to be efficiently supplied to the SCR catalyst 42 and the consumption of the urea water 46 to be reduced. Is reduced. Also, depending on the area where the vehicle is used, when the remaining amount of the urea water 46 in the urea tank 45 becomes low, the driver must be warned or the engine must be prohibited from restarting. It is desired to reduce the consumption of 46. Further, if the liquid urea water 46 remains in the exhaust passage 16A, when the engine is stopped, it is vaporized by the heat of the exhaust passage 16A (heat of the exhaust pipe) and becomes ammonia (NH ₃ ), and a part thereof remains as it is. It is a factor of ammonia slip which is discharged into the atmosphere and a factor of deposit.

Therefore, the exhaust gas purification device 30 according to this embodiment, are arranged urea water resupply member 48 into the exhaust passage 16A between the mixer 47 and the SCR catalyst 42. In the present embodiment, it is assumed that the exhaust passage 16A is disposed substantially horizontally. The urea water resupply member 48 resupplies the liquid urea water 46 stored in the exhaust passage 16A into the exhaust gas G. In the present embodiment, the exhaust passage 16A is formed by the exhaust pipe of the cross-sectional plane circular. Therefore, the liquid urea water 46 in the exhaust passage 16A accumulates in the bottom 16Ab, which is the lowermost portion of the exhaust passage 16A.

As shown in FIGS. 2A and 2B, the urea water re-supply member 48 has a contact portion 481 that is attached in contact with the inner surface 16Aa of the exhaust passage 16A, and a center of the exhaust passage 16A from the contact portion 481. It has an inclined portion 482 that is inclined upward in the direction (the direction of arrow A). The inclined portion 482 has a urea rising portion 483 for raising the liquid urea water 46.
The urea water re-supply member 48 is a metal plate-like member having excellent corrosion resistance and heat resistance such as stainless steel, and a part thereof is bent to integrally form the contact portion 481 and the inclined portion 482. Has formed. The urea water re-supply member 48 is attached to the bottom 16Ab of the exhaust passage 16A where the urea water 46 easily accumulates in the exhaust passage 16A by fixing the contact portion 481 by welding, screws, or the like.

In the present embodiment, the urea water re-supply member 48 is disposed such that the inclined portion 482 is located on the exhaust downstream side of the contact portion 481. Of course, the inclined portion 482 may be disposed so as to be located on the exhaust upstream side of the contact portion 481.
The bending angle θ of the inclined portion 482 with respect to the contact portion 481 is about 5 to 60 °. This is because, if the bending angle θ is increased, the area that blocks the exhaust passage 16A is increased, which may obstruct the flow of the exhaust gas G. If the flow of the exhaust gas G is hindered, not only can the urea water 46 not be sufficiently supplied to the SCR catalyst 42, but also the exhaust resistance increases. For this reason, in the present embodiment, the bending angle θ is set to the above value.

  The urea rising portion 483 of the urea water re-supplying member 48 shown in FIG. 2 includes a plurality of cuts (slits) 486 formed so as to straddle the inclined portion 482 and the contact portion 481. The slits 486 are formed at equal intervals in the width direction B of the urea water re-supply member 48 with a width that allows the liquid urea water 46 stored in the bottom 16Ab to rise by capillary action. In the present embodiment, the width of each slit 486 is set to 0.1 to 3.0 mm. The urea rising portion 483 has one end 483a extending to the contact portion 481, and the other end 483b extending to the tip 482a of the inclined portion 482, and is open.

  In the present embodiment, since the contact portion 481 of the urea water re-supply member 48 is disposed on the bottom 16Ab where the urea water 46 accumulates, the bending position 485, which is the joining position of the contact portion 481 and the inclined portion 482, It is formed in the middle of the cut portion (slit 486) of the portion 483. For this reason, one end 483 a of the urea rising portion 483 constituted by the plurality of slits 486 is positioned up to the bottom 16 Ab where the urea water 46 is stored, so that the urea water 46 is introduced into the urea rising portion 483. It is easy to be done.

  When the urea water re-supplying member 48 having such a configuration is provided, the liquid urea water 46 collected in the bottom 16Ab of the exhaust passage 16A becomes the contact portion 481 of the urea water re-supplying member 48 as shown in FIG. The urea rising portion 483 constituted by a plurality of slits 486 formed on the inclined surface 482 rises from one end 483a to the other end 483b by the action of capillary action. At this time, the urea water re-supply member 48 itself is heated by the exhaust gas G, and the urea water 46 rising in the urea rising portion 483 has a smaller mass than the state where it is accumulated in the bottom 16Ab. It is easy to evaporate due to the heat. Further, since the liquid urea water 46 is conveyed by the urea rising portion 483 to the center portion (center side) of the exhaust passage 16A where the flow rate of the exhaust gas G is faster than the state where it is accumulated in the bottom portion 16Ab, It becomes easier to mix.

Therefore, the liquid urea water 46 can be reused as a reducing agent, and the urea water 46 injected into the exhaust passage 16 can be efficiently supplied to the SCR catalyst 42. This leads to a reduction in consumption. The reduction in the consumption of the urea water 46 suppresses the driver from stopping and restarting the engine 1 or replenishing the urea water 46 due to the shortage of the urea water, leading to improvement in drivability.
Further, since the liquid urea water 46 is less likely to remain in the exhaust passage 16A, it is possible to suppress the generation of deposits and to suppress the ammonia slip when the engine is stopped.

FIGS. 4A and 4B show a first modification of the urea water re-supply member.
Although the urea water re-supply member 48 shown in FIG. 3 is constituted by one plate-like member, as shown in FIGS. 4A and 4B, a plurality of plate-like members processed into the same shape are used. The urea water re-supply member 48A may be formed by joining together. When joining a plurality of plate members together, they are joined so that a gap 484 is formed between the opposing surfaces. It is preferable that the width of the gap 484 is set so that the urea water 46 can move up the gap 484 by capillary action. When a plurality of plate members are joined to each other, the urea rising portions 483 and 483 formed on the inclined portion 482 of each plate member are joined so as to be shifted in the width direction B. By joining in this way, the number of urea rising portions (slits 486) 483 formed per unit area increases, so that the accumulated liquid urea water 46 can be efficiently sucked up and raised to return to the exhaust gas G. It is preferable because it is possible.

FIG. 5 shows a second modification of the urea water re-supply member. In the urea water re-supply members 48 and 48A, the urea rising portions 483 formed by the plurality of slits 486 are formed at equal intervals in the width direction B. However, in the urea water re-supplying member 48B according to the second modification, the urea rising portion 483 (at the center portion 482c of the inclined portion 482 located closer to the bottom 16Ab of the exhaust passage 16A where the urea water 46 easily accumulates in the width direction B). The slits 486) were formed to have a higher density so that the (slits 486) on the side portions 482d and 482e side of the inclined portion 482 were sparser than the central portion 482c.
By increasing the density of the urea rising portion 483 (slit 486) located in a portion where the urea water 46 easily accumulates, the accumulated liquid urea water 46 can be efficiently sucked up, raised and returned to the exhaust gas G. It is preferable because it is possible.

FIG. 6 shows a third modification of the urea water re-supply member. In the urea water re-supply members 48 and 48A, the urea rising portions 483 constituted by the plurality of slits 486 are formed at equal intervals in the width direction B.
The liquid urea water 46 in the exhaust passage 16A flows along the inner surface 16Aa of the exhaust passage 16A to the bottom surface 16Ab. However, depending on the flowing position and the amount of the urea water 46, the amount stored in the bottom 16Ab is small. A case where the amount of wraparound to the inclined portion 482 side is small is also assumed.

For this reason, in the urea water re-supply member 48C according to the third modification, the urea rising portions 483 (slits) are provided on the side portions 482d and 482e of the inclined portion 482 that is the upstream portion of the flow of the urea water 46 in the width direction B. 486), and the urea rising portion 483 (slit 486) is formed to be less dense in the central portion 482c of the inclined portion 482 than in the side portions 482d and 482e.
When the density of the urea rising portion 483 (slit 486) located on the upstream side of the flow of the urea water 46 is increased, the urea water 46 flowing on the inner surface 16Aa toward the bottom 16Ab and the contact portion 481 on the bottom 16Ab are formed. The urea water 46 flowing from the urea to the inclined portion 482 side can be introduced into the urea rising portion 483 more quickly and raised. Therefore, not only the liquid urea water 46 accumulated in the bottom portion 16Ab but also the urea water 46 flowing in the exhaust passage 16A can be efficiently sucked and raised, and returned to the exhaust gas G, which is preferable.

FIG. 7 is a diagram illustrating a schematic configuration of an exhaust gas purification device 30 according to a second embodiment of the present invention in which the arrangement location of the urea water re-supply member 48 is changed. In the first embodiment, the urea water re-supply member 48 is disposed in the exhaust passage 16A that is disposed horizontally at the exhaust upstream side of the SCR catalyst 42.
However, the exhaust passage 16A may be arranged at an angle, and the mixer 47 may be arranged at the inclined exhaust passage 16A. When the urea water 46 is injected into the exhaust passage 16A from the urea water injection valve 41 in such an arrangement, the spray-like urea water 46 that cannot be dispersed by the mixer 47 becomes a liquid urea water 46 and is discharged. It flows down toward the SCR catalyst 42 in the passage 16A. When giving priority to suppressing the generation of the deposit, the distance of the urea water 46 flowing in a liquid state is not short.
Therefore, in the present embodiment, the urea water re-supply member 48 is disposed on the bottom 16Ab immediately downstream of the mixer 47 disposed in the inclined exhaust passage 16A. Arranging the urea water re-supplying member 48 at such a position is preferable because the urea water 46 flowing through the inclined bottom portion 16Ab can be efficiently sucked up, raised and returned to the exhaust gas G.

  FIG. 8 is a diagram showing a schematic configuration of an exhaust gas purification device 30 according to a third embodiment of the present invention. In the first and second embodiments, one urea water re-supply member is disposed between the mixer 47 and the SCR catalyst 42 in the exhaust passage 16A. However, when the amount of the liquid urea water 46 injected in the form of a spray into the exhaust passage 16A and not mixed in the exhaust gas G but accumulated in the bottom 16Ab is large, one urea water re-supply member is not sufficient. Is also assumed.

For this reason, in this embodiment, a plurality of urea water re-supply members are arranged in the exhaust passage 16A at intervals in the exhaust gas flow direction. In the present embodiment, two urea water re-supply members 48 having the same shape are arranged.
By arranging the plurality of urea water re-supply members 48 in this manner, the urea water 46 injected into the exhaust passage 16A can be more efficiently supplied to the SCR catalyst 42, and the consumption of the urea water 46 It also leads to a reduction in volume. The reduction in the consumption of the urea water 46 suppresses the driver from stopping and restarting the engine 1 or replenishing the urea water 46 due to the shortage of the urea water, which leads to further improvement in drivability.
Further, since the liquid urea water 46 is less likely to remain in the exhaust passage 16A, it is possible to suppress the generation of deposits and to further suppress the ammonia slip when the engine is stopped.

FIG. 9 is a diagram showing a list of a plurality of modified examples of the urea water re-supply member. 9A and 9B are the urea water re-supply member 48 and the urea water re-supply member 48A described above. The urea water re-supply member 48 and the urea water re-supply member 48A are conveniently referred to as a slit type.
9 (c) and 9 (d) show urea water re-supply members 48D and 48E including a contact portion 481 and an inclined portion 482, and a urea rising portion 483 formed on the inclined portion 482 constituted by a plurality of grooves 487. Is shown. The width of each groove 487 was formed wider in the width direction B than the urea water re-supply members 48 and 48A. The urea water re-supply member 48D is formed of a single plate-like member, whereas the urea water re-supply member 48E is processed into the same shape as the urea water re-supply member 48D, similarly to the urea water re-supply member 48A. A plurality of plate-like members are joined together. That is, here, the urea water re-supply member 48E is configured by stacking two urea water re-supply members 48D. These urea water re-supply members 48D and 48E are referred to as a comb type for convenience.

FIGS. 9E and 9F show urea water re-supply members 48F and 48G each including a contact portion 481 and an inclined portion 482, and constituted by a plurality of holes 488 of a urea rising portion 483 formed in the inclined portion 482. Is shown. The urea water re-supply member 48F is formed of a single plate-like member, whereas the urea water re-supply member 48G has the same shape as the urea water re-supply member 48A. A plurality of processed plate members are joined together. That is, here, the urea water re-supply member 48G is configured by stacking two urea water re-supply members 48F. These urea water re-supply members 48F and 48G are referred to as a hole type for convenience. The diameter of each hole 488 ranges from 2 mm to about 10 mm. Of course, a large number of holes 488 having the same diameter may be formed, or holes 488 having different diameters may be formed in combination. In the case of the urea water resupplying member 48F, the urea water 46 flowing from the contact portion 481 to the inclined surface 482 accumulates in the lowermost hole 488 rather than rises in the urea rising portion 483 by capillary action, and has a surface tension. It is presumed that the urea water 46 formed in the form of a droplet moves sequentially to the adjacent hole 488 and rises toward the tip 482a of the inclined surface 482. For this reason, it is preferable that the interval between the holes 488 constituting the urea rising portion 483 is an interval at which the urea water 46 which has been dropped due to surface tension can move.
Alternatively, a plurality of holes 488 may be formed on the inclined surface 482, and a slit may be formed so that at least the adjacent holes 488 communicate with each other to form the urea rising portion 483. In this case, the liquid urea water 46 can rise toward the tip 482a of the inclined surface 482 at the current state of the capillary.
In the urea water re-supply member 48G, since two urea water re-supply members 48F, which are the same plate-shaped member, are overlapped and joined, a gap 484 where a capillary phenomenon occurs between the urea water re-supply members 48F is formed. The urea water 46 can rise toward the tip 482a of the inclined surface 482 at the current state of the capillary.

  9 (g) and 9 (h) show a urea solution including a contact portion 481 and an inclined portion 482, in which the inclined portion 482 is formed by a plurality of projections 489, and a urea rising portion 483 is formed between the projections 489. The resupply members 48H and 48I are shown. Each projection 489 is formed in a mountain shape that tapers toward the tip 482a of the inclined surface 482. The urea water re-supply member 48H is made up of a single plate-like member, whereas the urea water re-supply member 48I is made of a plurality of plate-like members processed into the same shape as the urea water re-supply member 48A. Are joined to each other. That is, here, the urea water re-supply member 48I is configured by stacking two urea water re-supply members 48H. These urea water resupply members 48H and 48I are referred to as a tree type for convenience.

  When the inclined surface 482 is formed by the plurality of protrusions 489 formed in such a mountain shape and the space between the adjacent protrusions 489 is configured as the urea rising portion 483, the urea introduced into the urea rising portion 483 from the bending position 485. The water 46 rises toward the tip of the projection 489 due to surface tension, capillary action, or the like. In addition, since the projection 489 has a thin tip, it is preferable that the urea water 46 be easily vaporized when heated by exhaust gas.

  Even in the case of each of the urea water re-supply members shown in FIGS. 9C to 9H, the density of the groove 487, the hole 488, and the chevron projection 489 is reduced as in the urea water re-supply members 48A and 48B. Of course, you can change it.

  In each of the embodiments and the modifications, the contact portion 481 is attached so as to be in close contact with the bottom portion 16Ab of the exhaust passage 16A. However, as shown in FIG. 10A, the contact portion 481 and the bottom portion 16Ab of the exhaust passage 16A are provided. May be attached so that a gap 490 is formed between the two. In this case, when the urea water 46 accumulated in the bottom 16Ab moves from the contact surface 481 to the inclined surface 482, as shown in FIG. 6, without passing through the side portions 482d and 482e of the inclined surface 482. It is preferable because it can be guided. Also, as shown in FIG. 10B, when a heat-resistant penetrating member 491 is interposed between the contact portion 481 and the bottom 16Ab of the exhaust passage 16A, as shown in FIG. 10B, the heat accumulates at the bottom 16Ab. This is preferable because the liquid urea water 46 can be guided to the inclined surface 482 side through the osmotic member 491.

  Further, each urea water re-supply member is made of a porous material such as impregnable metal or ceramic, and a contact portion 481 is formed in a place (bottom part 16Ab) where the urea water 46 is stored in the exhaust passage 16A. By attaching the urea water, the liquid urea water 46 accumulated in the bottom portion 16Ab can permeate the urea water re-supply member itself and travel along the inclined surface 482 to rise. In the case where the urea water re-supply member itself is an impregnable material or a porous member as described above, the inclined surface 482 itself functions as a urea rising portion, so that the slit 486, the groove 487, the hole 488, and the chevron are provided. This is preferable because the processing of the projection 489 and the like becomes unnecessary.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specified in the above description, the present invention described in the claims Various modifications and changes are possible within the scope of the gist.
The effects described in the embodiments of the present invention merely enumerate the most preferable effects resulting from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 16 ... In an exhaust passage, 41 ... Urea water supply part, 42 ... Selective reduction catalyst, 46 ... Urea water, 47 ... Dispersing member, 48, 48 ( A to I) urea water re-supply member, 481 contact part, 482 inclined part, 482d, 482e part upstream of urea water flow, 483 urea rising part , 486, cut, 488, hole, A, central direction of exhaust passage, 482c, part where urea water easily accumulates, G, exhaust

Claims (8)

A urea water supply unit that supplies urea water into an exhaust passage through which exhaust gas discharged from the internal combustion engine flows,
A selective reduction catalyst disposed on the exhaust downstream side of the urea water supply unit and selectively reducing nitrogen oxides contained in the exhaust gas using the urea water supplied from the urea water supply unit as a reducing agent;
A dispersing member that is disposed in an exhaust passage between the urea water supply unit and the selective reduction catalyst and disperses the urea water injected from the urea water supply unit;
The dispersion member and disposed in the exhaust passage between said selective reduction catalyst, and a re-supplying the urea water resupply member urea water liquid in said exhaust in said exhaust passage,
The urea water re-supply member,
A contact portion attached to an inner surface of the exhaust passage so as to have a gap with the inner surface ;
Anda inclined oblique portion inclined toward the center of the exhaust passage from said contact portion,
The inclined portion,
Cut in the inclined portion, or an exhaust gas purification apparatus characterized by urea ascender raising the urea water by providing a hole.   The exhaust gas purification apparatus according to claim 1, wherein the urea rising portion is formed so as to straddle the inclined portion and the contact portion.   The exhaust gas purification apparatus according to claim 1, wherein the urea water re-supply member is disposed immediately downstream of the dispersion member on the exhaust gas downstream side.   The urea rising portion is a portion where the urea water easily accumulates in the exhaust passage, and the density of the urea rising portion is increased, and the urea rising portion has a high density. Exhaust purification equipment.   The density of the urea rising part is raised in the part of the urea rising part in a part of the exhaust passage which is on the upstream side of the flow of the liquid urea water. The exhaust gas purification apparatus according to claim 1.   The exhaust gas purification apparatus according to any one of claims 1 to 5, wherein the urea water re-supply member is formed by joining a plurality of plate members together. The urea water resupply member, an exhaust gas purification according to any one of claims 1 to 6, characterized in that arranged in plural and in the exhaust passage between said selective reduction catalyst and the dispersion member apparatus. A urea water supply unit that supplies urea water into an exhaust passage through which exhaust gas discharged from the internal combustion engine flows,
A selective reduction catalyst disposed on the exhaust downstream side of the urea water supply unit and selectively reducing nitrogen oxides contained in the exhaust gas using the urea water supplied from the urea water supply unit as a reducing agent;
A dispersing member that is disposed in an exhaust passage between the urea water supply unit and the selective reduction catalyst and disperses the urea water injected from the urea water supply unit;
A urea water re-supply member disposed in an exhaust passage between the dispersion member and the selective reduction catalyst, and re-supplying liquid urea water into the exhaust gas in the exhaust passage;
The urea water re-supply member,
A contact portion that is attached in contact with the inner surface of the exhaust passage;
An inclined portion inclined from the contact portion toward a center direction of the exhaust passage,
The inclined portion,
A urea rising portion that raises urea water by forming a cut or a hole in the inclined portion is formed,
The exhaust gas purifying device, wherein the urea rising portion is formed so as to straddle the inclined portion and the contact portion.

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