JP2017218959A - Exhaust device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce the number of components by providing a reinforcement member with a sound-dampening and straightening function.SOLUTION: An exhaust device for an engine includes: an exhaust pipe 12 in which exhaust gas is caused to flow; a cylindrical casing 20 provided downstream of the exhaust pipe 12 and having catalysts 13, 14 accommodated therein; a cylindrical member 25 extending from a downstream end of the exhaust pipe 12, formed to have a cylindrical shape with an inner diameter smaller than that of the casing 20, and having a cylindrical surface at least part of which is inserted into the casing 20 and on which a plurality of first vent holes 25A are formed in a penetrating manner; and a reinforcement member 30 including a tapered surface 30A that is inclined to the axial center side of the casing 20 from the upstream side toward the downstream side, having a plurality of second vent holes 31 formed on the tapered surface 30A in a penetrating manner, and having an upstream side fixed to an inner peripheral surface of the casing 20, and a downstream side fixed to an outer cylindrical surface located downstream of the first vent holes 25A of the cylindrical member 25.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an engine exhaust device.

  In general, the exhaust system of an engine includes an oxidation catalyst that oxidizes carbon monoxide (CO) and hydrocarbons (HC) in exhaust gas, a particulate filter that collects particulate matter (PM), and nitrogen. A NOx catalyst or the like for purifying the compound (NOx) is provided.

  These catalysts and filters are accommodated in a casing whose diameter is larger than that of the exhaust pipe extending from the exhaust manifold. For this reason, the exhaust gas flowing into the casing having a large inner diameter from the exhaust pipe having a small inner diameter passes through the vicinity of the center of the catalyst or filter without being diffused in the casing, and the purification ability of the catalyst or filter is reduced. There are issues that cannot be fully utilized.

  As a technique that can solve such a problem, for example, in Patent Document 1, a cylindrical punching metal for diffusion having a plurality of vent holes on the upstream side of the oxidation catalyst in the casing is inserted and the cylindrical shape is inserted. A structure is disclosed in which a rectifying disc-shaped baffle plate having a plurality of ventilation holes is disposed in a space between a punching metal and an oxidation catalyst.

JP 2009-047016 A

  By the way, in the structure like the above prior art, as shown in FIG. 4, since the cylindrical punching metal 111 extending from the exhaust pipe 100 is inserted on the upstream side of the casing 110, there is a large space on the upstream side of the oxidation catalyst 114. Arise. For this reason, in order to ensure the strength of the casing 110 particularly on the upstream side, it is necessary to provide a reinforcing member 113 having a truncated cone shape, for example. However, in such a reinforcing structure, in addition to the disk-shaped baffle plate 112 having a silencing and rectifying function, the reinforcing member 113 is separately provided, which causes an increase in cost due to an increase in the number of parts, an increase in assembly man-hours, and the like. There is.

  The technology of the present disclosure aims to effectively reduce the number of parts by providing a reinforcing member with a silencing rectification function.

  The technology of the present disclosure includes an exhaust pipe that circulates exhaust gas discharged from the engine, a downstream side of the exhaust pipe, and a carrier that carries a catalyst that purifies the exhaust gas therein. A cylindrical casing having an inner diameter larger than that of the exhaust pipe, and extending from the downstream end of the exhaust pipe, and having an inner diameter smaller than that of the casing, and at least part of the cylindrical surface Is inserted upstream of the carrier in the casing, and a cylindrical member having a plurality of first vent holes formed through the inserted cylindrical surface, and the casing from the upstream side toward the downstream side. And a plurality of second vent holes are formed through the tapered surface, and the upstream side of the tapered surface is fixed to the inner peripheral surface upstream of the carrier of the casing. , That Downstream, characterized in that it comprises a reinforcement member fixed to the outer cylindrical surface of the downstream side of the first vent hole of the tubular member.

  In addition, the reinforcing member is formed in a truncated cone shape, the plurality of second vent holes are formed through the conical surface thereof, and the large-diameter side end thereof is an inner peripheral surface upstream of the carrier of the casing. In addition, the small-diameter side end may be fixed to the outer cylindrical surface on the downstream side of the first vent hole of the cylindrical member.

  In addition, the large-diameter side end is fixed to the inner peripheral surface of the casing on the upstream side of the first vent hole so that the reinforcing member can accommodate the first vent hole inside the conical surface. Is preferred.

  According to the technique of the present disclosure, the number of components can be effectively reduced by providing the reinforcing member with a muffler rectifying function.

It is a typical whole block diagram which shows the exhaust apparatus of the engine which concerns on this embodiment. It is typical sectional drawing which shows the principal part of the exhaust apparatus of the engine which concerns on this embodiment. It is a typical perspective view which shows the reinforcement member which concerns on this embodiment. It is typical sectional drawing explaining the exhaust apparatus of the conventional engine.

  Hereinafter, an exhaust system for an engine according to an embodiment of the present invention will be described with reference to the accompanying drawings. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As shown in FIG. 1, an exhaust pipe 12 through which exhaust gas flows is connected to an exhaust manifold 11 of a diesel engine (hereinafter simply referred to as an engine) 10. A casing 20 that houses the first and second oxidation catalysts 13 and 14 is provided on the downstream side of the exhaust pipe 12. An exhaust outlet pipe 15 for leading exhaust gas from the casing 20 is connected to the downstream end of the casing 20. Further, an upstream punching metal 25, a downstream punching metal 24, and a reinforcing member 30, which will be described in detail later, are provided inside the casing 20.

  As shown in FIG. 2, the casing 20 has a substantially hollow cylindrical shape whose inner diameter is larger than that of the exhaust pipe 12. More specifically, the casing 20 includes a cylindrical casing main body 21, a flat circular upstream plate 22 that closes the upstream opening of the casing main body 21, and a flat circular downstream plate 23 that closes the downstream opening of the casing main body 21. I have.

  In the casing main body 21, the first oxidation catalyst 13 and the second oxidation catalyst 14 are accommodated adjacent to each other at a substantially central portion in the axial direction. A predetermined space is secured between the upstream side of the first oxidation catalyst 13 and the upstream side plate 22 and between the downstream side of the second oxidation catalyst 14 and the downstream side plate 23.

  A through hole through which the exhaust lead-out pipe 15 is inserted is formed substantially at the center of the downstream plate 23. A cylindrical downstream punching metal 24 having a silencing function is provided in the casing body 21 between the second oxidation catalyst 14 and the downstream plate 23. This downstream punching metal 24 is connected to the upstream end of the exhaust outlet pipe 15 inserted into the casing 20.

  A through hole through which the upstream punching metal 25 extending from the exhaust pipe 12 is inserted is formed in the approximate center of the upstream plate 22. An annular flange 22A that protrudes upstream is formed at the periphery of the through hole. The outer peripheral surface of the upstream punching metal 25 is fixed to the inner peripheral surface of the flange 22A by welding or the like.

  The upstream punching metal 25 has a cylindrical shape that is substantially the same diameter as the exhaust pipe 12, and a plurality of vent holes 25 </ b> A are formed through the front (downstream) cylindrical surface inserted into the casing 20. . That is, the exhaust gas that has flowed into the upstream punching metal 25 from the exhaust pipe 12 passes through each vent hole 25A and is diffused in the radial direction into the casing 20. The upstream punching metal 25 is provided with a reinforcing member 30 that ensures the strength of the upstream side of the casing 20.

  As shown in FIGS. 2 and 3, the reinforcing member 30 has a substantially truncated cone shape, and a plurality of vent holes 31 are formed through the conical surface 30 </ b> A. The small diameter side end 30 </ b> B of the reinforcing member 30 is formed so that its inner diameter is substantially the same as the outer diameter of the upstream punching metal 25. Further, the small diameter side end 30B of the reinforcing member 30 is fixed to the outer peripheral surface of the upstream punching metal 25 by welding or the like on the inner peripheral surface thereof, so that the distal end (downstream side) of the upstream punching metal 25 is fixed. ) Close the opening.

  The large-diameter side end 30 </ b> C of the reinforcing member 30 is formed so that its outer diameter is substantially the same as the inner diameter of the casing body 21. Further, the large-diameter side end 30C of the reinforcing member 30 has an outer peripheral surface on the inner peripheral surface of the casing body 21 on the upstream side of the first oxidation catalyst 13, and preferably each vent hole 25A of the upstream punching metal 25 has a conical surface. It is fixed by welding or the like to the inner peripheral surface of the casing body 21 on the upstream side of each air hole 25A so as to be accommodated in the interior of 30A.

  That is, the strength on the upstream side of the casing 20 is fixed by fixing the upstream side of the first oxidation catalyst 13 of the casing body 21 and the tip (downstream) of the upstream punching metal 25 by the truncated conical reinforcing member 30. Is effectively secured. Further, since the plurality of vent holes 31 are formed in the conical surface 30A of the reinforcing member 30, the exhaust gas diffused in the radial direction into the casing 20 by the upstream punching metal 25 passes through the vent holes 31. The sound is silenced at the same time and is rectified toward the first oxidation catalyst 13.

  As described in detail above, according to the exhaust device of the present embodiment, the casing 20 is formed by fixing the inner peripheral surface of the casing body 21 and the outer peripheral surface of the upstream punching metal 25 by the truncated conical reinforcing member 30. The exhaust member 31 is provided with a plurality of vent holes 31 that allow exhaust gas to pass through the conical surface 30 </ b> A of the reinforcing member 30. It becomes possible to have. Thereby, it is not necessary to provide the baffle plate 112 and the reinforcing member 113 separately as in the conventional structure shown in FIG. 4, and the number of parts can be effectively reduced. Further, by reducing the number of parts, it is possible to effectively prevent an increase in cost and an increase in assembly man-hours.

  In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably and can implement.

  For example, the shape of the reinforcing member 30 is not limited to the truncated cone shape, and is fixed to the casing body 21 and the upstream punching metal 25 to ensure the strength of the casing 20, and at least a part of the reinforcing member 30 from the upstream side to the downstream side. Any other shape may be used as long as it includes a tapered surface inclined toward the center of the casing 20.

  Further, the carrier accommodated in the casing 20 is not limited to the oxidation catalysts 13 and 14, but may be a NOx catalyst, a particulate filter, or the like.

  The engine 10 is not limited to a diesel engine, and can be widely applied to an internal combustion engine in addition to a gasoline engine or the like.

10 Engine 11 Exhaust Manifold 12 Exhaust Pipe 13 First Oxidation Catalyst 14 Second Oxidation Catalyst 15 Exhaust Outlet Pipe 20 Casing 21 Casing Body 22 Upstream Plate 23 Downstream Plate 24 Downstream Punching Metal 25 Upstream Punching Metal 25A Ventilation Hole 30 Reinforcement Member 30A Conical surface 30B Small diameter side end 30C Large diameter side end

Claims (3)

An exhaust pipe for circulating exhaust gas exhausted from the engine;
A cylindrical casing provided downstream of the exhaust pipe and containing a carrier carrying a catalyst for purifying exhaust gas therein, the inner diameter of which is larger than that of the exhaust pipe;
The pipe extends from the downstream end of the exhaust pipe and has an inner diameter formed in a cylindrical shape smaller than the casing, and at least a part of the cylindrical surface is inserted upstream of the carrier in the casing. A cylindrical member having a plurality of first ventilation holes formed through the cylindrical surface formed;
The taper surface includes a tapered surface inclined toward the axial center of the casing from the upstream side to the downstream side, and a plurality of second vent holes are formed through the tapered surface, the upstream side being upstream of the carrier of the casing. A reinforcing member fixed to the inner peripheral surface on the side and a downstream side fixed to the outer cylindrical surface on the downstream side of the first vent hole of the cylindrical member. Exhaust system. The reinforcing member is formed in a truncated cone shape, and the plurality of second ventilation holes are formed through the conical surface, and the large-diameter side end is fixed to the inner peripheral surface upstream of the carrier of the casing. The engine exhaust device according to claim 1, wherein the small-diameter side end is fixed to the outer cylindrical surface on the downstream side of the first ventilation hole of the cylindrical member. The large diameter side end is fixed to the inner peripheral surface of the casing on the upstream side of the first ventilation hole so that the reinforcing member houses the first ventilation hole inside the conical surface. An exhaust system for an engine according to 1.

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