JP2008163917A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide excellent purifying efficiency without adding a special device even if exhaust gas flowing into an exhaust emission control device is in a spiral flow. <P>SOLUTION: The exhaust emission control device 1 is equipped with an exhaust gas inflow pipe 3 connected to a turbo supercharger, a cone 4 continued to the downstream side of the exhaust gas inflow pipe 3, and an exhaust gas purifying body 5 at the downstream side of the cone 4. The exhaust gas inflow pipe 3 is equipped with a straight pipe 3a connected to the turbo supercharger, and a bent part 3b for making the straight pipe part 3a communicate with the cone 4. A pipe axis 3c of the straight pipe 3a is offset OF1 to the turning direction side R of the spiral flow of the exhaust gas with respect to an axis 5a of the exhaust gas purifying body 5 viewed in the axial direction of the pipe axis 3c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification device for an internal combustion engine.

  As an apparatus for purifying exhaust gas discharged from an internal combustion engine such as an automobile, an exhaust gas purifying apparatus having a catalyst carrier on which a catalyst is supported is known.

  In order to increase the exhaust gas purification efficiency using such an exhaust gas purification device, the exhaust gas flow rate is made to flow uniformly through the catalyst carrier by making the flow velocity distribution of the exhaust gas uniform with respect to the upstream end face of the catalyst. is important.

  By the way, when the turbocharger is arranged upstream of the exhaust gas purification device, the exhaust gas becomes a spiral flow due to the turbine turning of the turbocharger, and the bent pipe (elbow), the enlarged diameter part (cone) Part)) and flows into the exhaust gas purification device as a spiral flow. There is a problem that the spiral flow is unevenly distributed in the expanded diameter portion (cone portion) and non-uniformly hits the upstream end face of the catalyst, and it is difficult to achieve the desired purification efficiency in the catalyst. As a means for improving the exhaust gas purification efficiency in such a case, Patent Document 1 discloses an exhaust gas purification apparatus in which a flow dividing means is installed at a bent portion of the exhaust passage to forcibly disperse the drift. Proposed.

  However, the exhaust gas purification device described in Patent Document 1 has a concern of inducing an increase in back pressure by installing a separate flow correction means (a flow dividing portion) and deteriorating engine performance. In addition, installation costs and assembly work increase, and there is a concern about durability in a high-temperature atmosphere.

JP 2003-49640 A

  In view of the above problems, an object of the present invention is to provide excellent purification efficiency without adding a special device even if the exhaust gas flowing into the exhaust gas purification device is a spiral flow.

  In order to solve the above-mentioned problem, in the first invention, an exhaust gas inflow pipe connected to the turbocharger, a cone part continuous to the downstream side of the exhaust gas inflow pipe, and a downstream side of the cone part In the exhaust gas purifying apparatus comprising an exhaust gas purifying body, the exhaust gas inflow pipe includes a straight pipe part connected to the turbocharger, and a bent part communicating the straight pipe part and the cone part. The tube axis of the straight pipe portion is offset to the swirl direction side of the spiral flow of the exhaust gas with respect to the central axis of the exhaust gas purifier when viewed in the axial direction of the tube axis.

  In the second invention, in the first invention, the tube axis of the downstream end portion of the bent portion is directed to the substantial center of the upstream end surface of the exhaust gas purifier, and the actual angle θ with respect to the upstream end surface is 15 ° ≦ θ ≦ 75 ° was set.

  ADVANTAGE OF THE INVENTION According to this invention, even if the exhaust gas which flows into an exhaust-gas purification apparatus is a spiral flow, the outstanding purification efficiency can be provided, without adding a special apparatus.

  The best mode for carrying out the present invention will be described based on the embodiment shown in FIGS. FIG. 1 is a schematic diagram showing a configuration of an exhaust system including a right side view of an exhaust gas purifying apparatus according to a first embodiment of the present invention, and FIG. 2 is an exhaust gas purifying apparatus according to the first embodiment of the present invention. FIG. 3 is a top view of the exhaust gas purifying apparatus according to the first embodiment of the present invention, and FIG. 4 is a pipe shaft of the straight pipe portion 3a in the exhaust gas purifying apparatus according to the first embodiment of the present invention. FIG. 5 is an enlarged sectional view taken along line AA in FIG. 3 showing the flow of exhaust gas when the turbine of the turbocharger turns rightward (viewed from the upstream side), and FIG. 5 shows the exhaust gas in FIG. FIG. 6 is a front view of the exhaust gas purifying apparatus according to the second embodiment of the present invention.

  1 to 5 show an exhaust gas purifying apparatus according to a first embodiment of the present invention. For example, as shown in FIG. 1, the exhaust system is configured such that an exhaust manifold 30 is connected to a plurality of exhaust ports 21 of the internal combustion engine 20, and a collective end portion 31 of the exhaust manifold 30 is on the turbine 41 side of the turbocharger 40. The exhaust gas purification device 1 is connected to the turbine 41. Note that, on the compressor 42 side of the turbocharger 40, an intake passage 23 provided with an air cleaner (not shown) and an intake passage 24 provided with an intake manifold (not shown) are connected. The exhaust gas discharged from the exhaust port 21 flows through the exhaust manifold 30 and then flows into the exhaust gas purification device 1 as a spiral flow A through the turbine 41.

  The exhaust gas purification apparatus 1 includes an exhaust gas inflow pipe 3 connected to the turbocharger 40 via a connection flange 2, a tapered cone part 4 continuous downstream of the exhaust gas inflow pipe 3, and a cone part 4 is illustrated at the downstream end of the exhaust gas outlet pipe 6, the outer cylinder 9 that houses the exhaust gas purification body 5 that is disposed downstream of the exhaust cylinder 4, the exhaust gas outlet pipe 6 that is disposed downstream of the outer cylinder 9. And a connection flange 7 connected to the downstream exhaust pipe. In this embodiment, the connection flange 2, the exhaust gas inflow pipe 3, the cone portion 4, the outer cylinder 9, the exhaust gas outflow pipe 6, and the connection flange 7 are all connected separately by welding, but are integrated with each other. It does not matter.

  The exhaust gas purifying body 5 is, for example, a ceramic monolith catalyst carrier having a catalyst supported on the surface thereof. As shown in FIG. It is stored. The exhaust gas purifying body 5 is not limited to a monolithic catalyst carrier, but may be a diesel particulate filter, a NOx adsorption / reduction catalyst carrier, a metal catalyst carrier or the like as long as it has a function of purifying exhaust gas. , You can choose freely.

  The exhaust gas inflow pipe 3 includes a straight pipe portion 3a that extends linearly from the turbocharger 40, and a bent portion 3b that allows the straight pipe portion 3a and the cone portion 4 to communicate with each other. As shown in FIG. 3, the pipe shaft 3 c of the straight pipe portion 3 a is an arrow that indicates the turning direction of the turbine 41 with respect to the central shaft 5 a of the exhaust gas purifying body 5 when viewed from the upstream side of the pipe shaft 3 c. Offset to the R side by a predetermined amount OF1. That is, when the swirl direction R of the spiral flow A is viewed from the side that looks clockwise, it is offset to the right.

  Next, the flow of exhaust gas in the exhaust gas purification apparatus 1 of the present embodiment will be described. As shown in FIG. 1, the exhaust gas turns into a spiral flow A due to the turning of the turbine 41, and flows in the direction of the tube axis 3c while turning along the tube wall of the straight portion 3a in the straight portion 3a. Then, when the spiral flow A reaches the bent portion 3 b, as shown in FIG. 4, the course direction changes and part of the tube wall that restrains the spiral flow disappears, and the upstream end surface 5 b of the exhaust gas purifying body 5 is removed. It changes to the diagonal flow B which goes.

  As shown in FIG. 4, when the spiral flow A is a right turn R in the axial view of the tube shaft 3c, the mixed flow B has a property of gently turning to the right. In the portion 3b, there is a tendency to be biased toward the region Y on the right side of the drawing. Therefore, the exhaust gas uniformly hits the entire area of the upstream end surface 5b, and the exhaust gas can be uniformly flowed into the exhaust gas purifying body 5 without unevenness, thereby achieving the desired purification efficiency.

  In the exhaust gas purification apparatus 1 of the present embodiment, the tube shaft 3d at the downstream end portion of the bent portion 3b is placed at the substantially center 5c of the upstream end surface 5b of the exhaust gas purification body 5 in order to exhibit even better purification efficiency. The actual angle θ between the tube shaft 3d and the upstream end surface 5b may be set to 15 ° ≦ θ ≦ 75 °.

  When the actual angle θ is set to θ <15 °, in FIG. 4, the mixed flow B tends to be biased to the left side of the upstream end surface 5b in the drawing, and the flow velocity distribution is uneven. On the other hand, when θ> 75 ° is set, it is not possible to eliminate the uneven flow generated by the spiral flow that has passed through the bent portion 3b. Regardless of the setting, the flow velocity distribution on the upstream end face 5b becomes non-uniform.

  FIG. 6 shows an exhaust gas purifying apparatus according to the second embodiment of the present invention. This embodiment is a case where the turbine turns left, and the tube shaft 13c of the straight pipe portion 13a is the same as the turning direction of the turbine with respect to the central shaft 15a of the exhaust gas purifying body 15 in the axial direction of the tube shaft 13c. This is offset to the left by a predetermined amount OF2. A feature of this embodiment is that a connecting pipe 16 is provided between the bent portion 13b and the cone portion 14 of the exhaust gas purifying device 11. In the exhaust gas purifying device 11, the actual angle θ1 between the tube shaft 13d at the downstream end of the bent portion 13b and the upstream end surface 15b of the exhaust gas purifying body 15 is set to 15 ° ≦ θ1 ≦ 75 ° for convenience of vehicle mounting. If it cannot be set, the actual angle θ2 between the tube end 16a at the downstream end of the connection tube 16 and the upstream end surface 15b is set to 15 ° ≦ θ ≦ 75 °, and the tube shaft 16a is connected to the upstream end surface 15b of the exhaust gas purifier 15. The light is directed to the center 15c or the vicinity thereof. According to the present embodiment, purification efficiency substantially equal to that of the first embodiment can be obtained.

  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. For example, the number of connecting pipes in the second embodiment may be any number. Further, the outer cylinder of the bent portion, the cone portion, and the exhaust gas purifying body may be manufactured by a known press process and joined by welding or the like, or the pipe material may be reduced in diameter by a spinning process or the like.

FIG. 1 is a schematic diagram showing a configuration of an exhaust system including a right side view of an exhaust gas purifying apparatus according to a first embodiment of the present invention. The front view of the exhaust-gas purification apparatus which concerns on the 1st Embodiment of this invention The top view of the exhaust-gas purification apparatus which concerns on the 1st Embodiment of this invention XX line expanded sectional view of the exhaust-gas purification apparatus which concerns on the 1st Embodiment of this invention Flow velocity distribution diagram of upstream end face of exhaust gas purifying body according to first embodiment of the present invention The front view of the exhaust-gas purification apparatus which concerns on the 2nd Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Exhaust gas purification apparatus 3,13 Exhaust gas inflow pipe 3a, 13a Straight line part 3b, 13b Bending part 3c, 13c Pipe axis 3d, 13d Pipe axis 4,14 Cone part 5,15 Exhaust gas purification body 5a, 15a Center Center of shaft 5b, 15b upstream end face 5c, 15c

Claims (2)

In an exhaust gas purification apparatus comprising an exhaust gas inflow pipe connected to a turbocharger, a cone part continuous on the downstream side of the exhaust gas inflow pipe, and an exhaust gas purifier on the downstream side of the cone part,
The exhaust gas inflow pipe includes a straight pipe part connected to the turbocharger, and a bent part communicating the straight pipe part and the cone part, and the pipe axis of the straight pipe part is the pipe axis. The exhaust gas purification device is offset to the swirl direction side of the spiral flow of the exhaust gas with respect to the central axis of the exhaust gas purification body when viewed in the axial direction.   The tube axis of the downstream end portion of the bent portion is directed to substantially the center of the upstream end surface of the exhaust gas purifier, and the actual angle θ with respect to the upstream end surface is set to 15 ° ≦ θ ≦ 75 °. The exhaust gas purification device according to claim 1.

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