JP2009216074A - Exhaust emission control device, exhaust pipe for diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device excelling in a diffusion property and a mixture property of an additive into an exhaust gas, and an exhaust pipe for a diesel engine. <P>SOLUTION: This exhaust emission control device 1 is provided with an exhaust gas purification body 4 in an exhaust passage 6, and a swirling flow generation means 8 and an additive supply means 7 in the exhaust passage 6 on the upstream side of the exhaust gas purification body 4. In the exhaust emission control device, the swirling flow generation means 8 formed of a single plate is tilted with respect to the axis 6a of the exhaust passage 6, and installed on the inside surface 6b of the exhaust passage 6 by including the axis 6a, whereby two split passages 9 and 10 are formed on both sides of the swirling flow generation means 8, and the supply direction F of the additive from the additive supply means 7 is set orthogonal to the longitudinal direction of the plate 8 in a cross-sectional view orthogonal to the axis 6a of the exhaust passage 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification device mounted on an internal combustion engine such as a diesel engine and an exhaust pipe for a diesel engine.

  As an exhaust gas purification device mounted on an internal combustion engine such as a diesel engine, a diesel particulate filter (hereinafter referred to as DPF) that collects particulate matter (particulate matter, hereinafter referred to as PM) contained in the exhaust gas. And an exhaust gas purifier such as an oxidation catalyst carrier or a NOx reduction catalyst carrier in an exhaust passage is known.

  In order to improve the purification performance of the exhaust gas purification device, an additive is supplied into the exhaust gas. For example, in an exhaust gas purification apparatus in which an oxidation catalyst carrier is provided on the upstream side of the DPF, light oil is supplied as an additive into the exhaust gas, and the temperature of the exhaust gas is set to 600 by the oxidation reaction heat between the additive and the oxidation catalyst. DPM is regenerated by raising the temperature to more than ° C. and burning off the PM collected in the DPF.

  Further, in the exhaust gas purification apparatus provided with the NOx reduction catalyst carrier, for example, the NOx occluded in the NOx reduction catalyst carrier is supplied by supplying an additive such as urea water having the function of a reducing agent into the exhaust gas. The exhaust gas is purified by reducing the exhaust gas.

  By the way, when the additive is supplied into the exhaust gas as described above, the additive is diffused and uniformly mixed in the exhaust gas, and the mixed gas is caused to uniformly flow into the upstream end face of the exhaust gas purifier, thereby improving the purification performance. Improvements are being made. For example, in Patent Document 1, an additive supply means (injection nozzle) is provided in the exhaust flow path upstream of the exhaust gas purifier (reduction catalyst), and further, the exhaust flow path upstream of the additive supply means is provided in the exhaust flow path. There has been proposed an exhaust gas purification device provided with a swirl flow generating means for swirling exhaust gas in a spiral manner around the axis of the exhaust flow path. According to Patent Document 1, since the additive is supplied to the exhaust gas that has been swirled in advance, mixing of the additive and the exhaust gas is promoted.

  Further, Patent Document 2 proposes a fluid mixer in which a plurality of fluid reversing vanes are combined in an inclined manner with respect to the fluid flow direction and arranged in a comb-teeth shape on the cross section of the flow path.

However, in the exhaust gas purification devices described in Patent Documents 1 and 2, the structure of the swirl flow generating means and the fluid mixer is complicated, so it is difficult to adjust the uniform mixing of the additive and the exhaust gas. May become insufficient, and the pressure loss of the exhaust gas may increase due to the plurality of fins and vanes.
Japanese Patent No. 3892452 Japanese Utility Model Publication No. 53-153272

  In view of the above problems, an object of the present invention is to provide an exhaust gas purification device that is excellent in diffusibility and mixing of additives into exhaust gas.

  In order to solve the above problems, in the first invention, an exhaust gas purifying body is provided in the exhaust passage, and a swirling flow generating means and an additive supply means are provided in the exhaust passage upstream of the exhaust gas purifying body. In the exhaust gas purification apparatus provided, the swirl flow generating means comprising a single plate is inclined with respect to the axis of the exhaust flow path and is installed on the inner surface of the exhaust flow path including the shaft. Two divided flow paths are formed on both sides of the swirl flow generating means, and the supply direction of the additive from the additive supply means is orthogonal to the longitudinal direction of the plate in the cross-sectional view perpendicular to the axis of the exhaust flow path. .

  In the second aspect of the invention, the exhaust passage is provided with an exhaust gas purifier, the exhaust passage upstream of the exhaust gas purifier is provided with swirl flow generating means and additive supply means, and consists of a single plate. The swirling flow generating means is inclined with respect to the axis of the exhaust flow path and is installed on the inner surface of the exhaust flow path including the shaft so that two divided flow paths are provided on both sides of the swirling flow generating means. Diesel provided with an exhaust gas purifying device formed in the middle of the exhaust pipe so that the supply direction of the additive from the additive supply means is orthogonal to the longitudinal direction of the plate in the axial orthogonal cross section of the exhaust passage This is an engine exhaust pipe.

  ADVANTAGE OF THE INVENTION According to this invention, the exhaust-gas purification apparatus which is excellent in the diffusibility and mixing property of the additive in exhaust gas, and the exhaust pipe for diesel engines can be provided.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 is a longitudinal sectional view of an exhaust gas purifying apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a conceptual diagram showing a flow of exhaust gas, FIG. 3 is a cross-sectional view taken along line BB in FIG. 3, FIG. 5 is a comparison view with respect to FIG. 4, FIG. 6 is a cross-sectional view taken along line AA of the exhaust gas purifying apparatus according to the second embodiment of the present invention, and FIG. FIG. 8 is a sectional view taken along line AA of the exhaust gas purifying apparatus according to the third embodiment, FIG. 8 is a sectional view taken along line AA of the exhaust gas purifying apparatus according to the fourth embodiment of the present invention, and FIG. FIG. 10 is a longitudinal sectional view of an exhaust gas purification apparatus according to the sixth embodiment of the present invention, and FIG. 11 is a seventh sectional view of the present invention. FIG. 12 is a longitudinal sectional view of an exhaust gas purifying apparatus according to an eighth embodiment of the present invention, and FIG. It is a longitudinal sectional view of an exhaust gas purifying apparatus according to light of the ninth embodiment.

  The configuration of the exhaust gas purification device 1 will be described with reference to FIGS. 1 and 2. An exhaust gas purification body 4 composed of the oxidation catalyst carrier 2 and the DPF 3 is housed in the casing 5 via a holding member (not shown) such as a wire mesh or an alumina mat. A tapered cone 5a is formed on the upstream side (the left side in the figure) of the casing 5, and a tubular exhaust passage 6 is connected thereto. An additive supply means 7 is provided in the exhaust passage 6 toward the shaft 6a (in the centripetal direction). Further, the swirl flow generating means 8 is housed in the exhaust flow path 6 upstream of the additive supply means 7.

  The exhaust gas purification apparatus 1 can be provided in the middle of an exhaust pipe for a diesel engine, for example.

  As shown in FIG. 1, the swirling flow generating means 8 is inclined by an angle θ with respect to the shaft 6a of the exhaust passage 6 and includes the shaft 6a of the exhaust passage 6 as shown in FIG. The plate 8 is composed of a flat and rectangular single (one) plate 8, and the two divided flow passages 9 and 10 are formed on both sides of the plate 8 by installing the plate 8 on the inner surface 6 b. The angle θ is preferably 30 ° or more and 45 ° or less. If θ is smaller than 30 °, a swirl flow described later is not sufficiently generated, and there is a possibility that the exhaust gas and the additive are not sufficiently mixed. In addition, since the entire length of the plate 8 is long, there is a problem that the exhaust passage is long. On the other hand, if θ is greater than 45 °, the pressure loss of the exhaust gas may increase. The width W of the plate 8 is preferably about 1/3 of the diameter D of the exhaust flow path. If the width W is smaller than 1/3, the swirling flow described later is not easily generated, and the exhaust gas and the additive May not be sufficiently mixed, and if it is greater than 1/3, the pressure loss of the exhaust gas may increase.

  The additive supply means 7 is an addition valve, an injection nozzle or the like fixed to the exhaust flow path 6, and passes through the exhaust flow path 6 as shown in FIG. On the right side). Further, as shown in FIG. 2, the additive supply means 7 is arranged so that the additive is supplied (injected) perpendicular to the longitudinal direction of the plate 8 in a cross-sectional view orthogonal to the axis 6a. In addition, it is possible to avoid the additive from adhering to the plate 8 by disposing the additive supply means 7 away from the plate 8 on the downstream side in the direction of the axis 6a.

  Next, the flow of exhaust gas and mixing of additives in the present embodiment will be described with reference to FIGS. When exhaust gas G discharged from an internal combustion engine such as a diesel engine (not shown) collides with a plate 8 that is introduced into the exhaust passage 6 and inclined with respect to the shaft 6a, it is divided into divided passages 9 and 10 with the plate 8 as a boundary. After that, the swirl flows G1 and G2 along the inner surface 6b are obtained. The swirl flows G1 and G2 pass through the divided flow paths 9 and 10 and then collide with each other on the central plane 6c of the exhaust flow path 6 to become a bi-directional swirl flow with the central plane 6c as a boundary surface. Here, in the region where the distance between the plate 8 and the inner surface 6b is short (upper side and lower side in FIG. 4), the exhaust gas G changes into the swirl flows G1 and G2 along the inner surface 6b, but the region where the distance is long ( In the middle of FIG. 4, the exhaust gas G has a weak force reaching the inner surface 6 b, and remains in the generation of a small vortex g under the influence of the swirl flows G <b> 1 and G <b> 2. Is not strong). Then, by supplying the additive into the exhaust gas in a complicated flow state in which the swirl flows G1 and G2 and the vortex flow g are mixed, the additive collides with the exhaust gas and diffuses and is uniformly distributed in the exhaust gas. Mixed.

  Next, the relationship between the supply direction of the additive from the additive supply means 7 to the plate 8 and the mixing property will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, when the supply direction F of the additive from the additive supply means 7 is orthogonal to the longitudinal direction of the plate 8 in the cross-sectional view perpendicular to the axis 6 a of the exhaust flow path 6, the additive is swirled. G1 and G2 collide perpendicularly, and the additive is uniformly diffused and mixed by the collision energy.

  On the other hand, as shown in FIG. 5, when the supply direction F of the additive from the additive supply means 7 is set parallel to the longitudinal direction of the plate 8, the additive rides on the flow of the swirl flows G1, G2. The penetration force of the additive is difficult to weaken, the additive tends to be biased to the region H, and there is a possibility that the additive is not uniformly diffused and mixed. This deviation is particularly noticeable when the internal combustion engine is in a high load state, that is, when the flow velocity of the swirling flow is high.

  Therefore, the additive supply direction F from the additive supply means 7 is preferably orthogonal to the longitudinal direction of the plate 8.

  FIG. 6 is a cross-sectional view taken along line AA of the exhaust gas purifying apparatus according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  As for the plate 18, the bulging part 18a is integrally formed in the longitudinal direction center part. The shape and area of the bulging portion 18a are appropriately set according to the target mixing property of the exhaust gas and the additive.

  According to this embodiment, the same effect as that of the first embodiment can be obtained, and the mixing property of the exhaust gas and the additive can be adjusted and optimized.

  FIG. 7 is a cross-sectional view taken along line AA of the exhaust gas purifying apparatus according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  In the plate 28, a constricted portion 28a and a bulging portion 28b are continuously formed integrally in the longitudinal direction. The positions, shapes, and areas of the constricted portion 28a and the bulging portion 28b are appropriately set according to the target mixing property of the exhaust gas and the additive.

  According to this embodiment, the same effect as that of the first embodiment can be obtained, and the mixing property of the exhaust gas and the additive can be adjusted and optimized.

  FIG. 8 is a sectional view taken along line AA of the exhaust gas purifying apparatus according to the fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  The plate 38 is formed in a taper shape in the longitudinal direction. The taper shape is appropriately set according to the target mixing property of the exhaust gas and the additive.

  According to this embodiment, the same effect as that of the first embodiment can be obtained, and the mixing property of the exhaust gas and the additive can be adjusted and optimized.

  FIG. 9 is a cross-sectional view taken along line AA of the exhaust gas purifying apparatus according to the fifth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  A through hole 48 a is formed in the plate 48. The number, size, and arrangement of the through holes 48a are appropriately set according to the target mixing property of the exhaust gas and the additive and the pressure loss value.

  According to this embodiment, the same effect as that of the first embodiment can be obtained, and the mixing property and pressure loss of exhaust gas and additive can be adjusted and optimized.

  FIG. 10 is a longitudinal sectional view of an exhaust gas purification apparatus according to the sixth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  The exhaust gas purification device 11 includes a plate 58 that has a bent portion 58a and is bent into a dogleg shape with the axis 6a as a symmetrical axis.

  According to the present embodiment, the swirl flow is initially different from the upper side and the lower side in the figure with the shaft 6a as a boundary, and the mixing property of the exhaust gas and the additive is excellent.

  FIG. 11 is a longitudinal sectional view of an exhaust gas purification apparatus according to the seventh embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  The exhaust gas purification device 21 includes a plate 68 curved in the longitudinal direction.

  According to this embodiment, the same effect as the first embodiment can be obtained.

  FIG. 12 is a longitudinal sectional view of an exhaust gas purification apparatus according to the eighth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  The exhaust gas purification device 31 includes a plate 78 at a bent portion 6 d of the exhaust flow path 6. A tangent to the curved axis 6a in the bent portion 6d is defined as a virtual axis 6e, and the plate 78 is arranged inclined by an angle θ amount with respect to the virtual axis 6e.

  According to this embodiment, the same effect as the first embodiment can be obtained.

  FIG. 13 is a longitudinal sectional view of an exhaust gas purification apparatus according to the ninth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and the description is abbreviate | omitted.

  In the exhaust gas purification device 41, the additive supply means 7 is provided in the exhaust flow path 6 on the upstream side of the plate 8. The distance between the additive supply means 7 and the exhaust gas purification device 4, that is, the mixing path length can be earned, and the mixing of the additive is promoted.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, Even if there is a change of the range which does not deviate from the meaning of this invention, it is included in this invention. The shape, inclination angle θ, width W, plate thickness, etc. of the plate may be arbitrarily set according to the mixing property and pressure loss. Further, the plate is not limited to a flat plate, and may be a plate formed of a plurality of wavy or three-dimensionally different surfaces, or a plate curved, bent, or inclined in the width W direction. The plate may be asymmetric with respect to the center plane 6c or may be offset. Further, the DPF may have a function of reducing NOx by supporting a noble metal catalyst and an active oxygen release agent on the filter. Moreover, an additive is not specifically limited, such as a light oil, urea water, and another reducing agent.

1 is a longitudinal sectional view of an exhaust gas purification apparatus according to a first embodiment of the present invention. AA line sectional view in FIG. The conceptual diagram which shows the flow of the exhaust gas in the exhaust-gas purification apparatus which concerns on the 1st Embodiment of this invention. BB sectional view in FIG. Comparison with FIG. Sectional view on the AA line of the exhaust gas purification apparatus which concerns on the 2nd Embodiment of this invention. AA line sectional view of an exhaust gas purification device concerning a 3rd embodiment of the present invention. AA line sectional view of an exhaust-gas purification apparatus concerning a 4th embodiment of the present invention. Sectional view on the AA line of the exhaust-gas purification apparatus which concerns on the 5th Embodiment of this invention A longitudinal sectional view of an exhaust gas purification apparatus according to a sixth embodiment of the present invention A longitudinal sectional view of an exhaust gas purification apparatus according to a seventh embodiment of the present invention A longitudinal sectional view of an exhaust gas purification apparatus according to an eighth embodiment of the present invention. A longitudinal sectional view of an exhaust gas purification apparatus according to an eighth embodiment of the present invention.

Explanation of symbols

1,21,31 Exhaust gas purification device 2 Oxidation catalyst carrier 3 DPF
4 Exhaust gas purification body 5 Casing 6 Exhaust flow path 6a Shaft 6b Inner surface 6c Center surface 7 Additive supply means 8, 18, 28, 38, 48, 58, 68, 78 Plate (swirl flow generating means)
9, 10, 11, 12, 13, 14, 15, 16 Divided flow path

Claims (2)

In an exhaust gas purification apparatus comprising an exhaust gas purification body in an exhaust flow path, and comprising a swirling flow generating means and an additive supply means in the exhaust flow path upstream of the exhaust gas purification body,
The swirl flow generating means composed of a single plate is inclined with respect to the axis of the exhaust flow path, and is installed on the inner surface of the exhaust flow path including the shaft so that the two divided flow paths are swirled. Exhaust gas formed on both sides of the flow generation means, wherein the supply direction of the additive from the additive supply means is orthogonal to the longitudinal direction of the plate in a cross-sectional view perpendicular to the axis of the exhaust flow path Purification equipment.   An exhaust gas purification body is provided in the exhaust flow path, a swirl flow generation means and an additive supply means are provided in the exhaust flow path upstream of the exhaust gas purification body, and the swirl flow generation means comprising a single plate is provided. The two additives are formed on both sides of the swirling flow generating means by inclining with respect to the axis of the exhaust flow path and erected on the inner surface of the exhaust flow path including the shaft, A diesel engine comprising an exhaust gas purification device in the middle of an exhaust pipe in which an additive supply direction from a supply means is orthogonal to a longitudinal direction of the plate in an axial orthogonal cross section of the exhaust passage. Exhaust pipe.

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