Exhaust device for an engine and method for training the same

Abstract

Exhaust system for an engine, comprising: an exhaust gas cleaning device (Q) which is provided or can be mounted on an exhaust gas or outlet path of the engine and comprises a cleaning device body for cleaning exhaust gas emitted by the engine, which is received in a casing (35) of the exhaust gas cleaning device (Q), wherein the exhaust gas cleaning device (Q) comprises a GPF (gasoline particulate filter) (3) as an exhaust gas cleaning device; and an EGR device (W) which is connected to a downstream side in an exhaust gas flow direction of the exhaust gas cleaning device (Q) and recirculates a portion of the exhaust gas passing through the cleaning device body as EGR gas to an intake system of the engine, wherein an exhaust gas discharge opening (71) is provided at a downstream end section of the casing (35) of the exhaust gas cleaning device (Q) at a position, which is offset from a central axis (L3) of the cleaning device body, an EGR gas extraction opening (70) is provided on the downstream end section of the casing (35) of the exhaust gas cleaning device (Q) at a position which is offset on the opposite side to the exhaust gas discharge opening (71) from the central axis (L3) of the cleaning device body, and the EGR device (W) is provided on the same side as the EGR gas extraction opening (70) relative to the central axis (L3) of the cleaning device body, wherein an EGR gas extraction pipe (6) is connected to the EGR gas extraction opening (70) of a tip section of an EGR gas injection section (72A), which projects towards one side of the GPF (3) towards an opposite side to an arrangement side of an exhaust gas discharge pipe (5), and the EGR gas extraction tube (6) extends from the EGR gas extraction opening (70) towards one side of the engine body on the side of the GPF (3) parallel to the central axis (L3) of the cleaning device body of the GPF (3).

Description

[0001] The present invention relates to an exhaust device for an engine and to a method of forming an exhaust device for an engine.

[0002] Conventionally, an exhaust gas purifying device is provided for purifying exhaust gas in an exhaust path of an automotive engine such as a diesel engine or a gasoline engine.

[0003] Furthermore, EGR (exhaust gas recirculation), in which a part of the exhaust gas passed through the exhaust gas purifying device and cleaned is recirculated to an intake system, is used to prevent engine knocking or to reduce nitrogen oxide (NOx) (see, for example, JP 2004 - 176 554 A and JP 2012 - 031 782 A).

[0004] Herein, in a case where an EGR path is branched from a downstream side of the exhaust gas purifying device, if this EGR path is branched from a cone portion or a flange connecting to a main exhaust path of a casing of the exhaust gas purifying device, there is a concern that the flow (ventilation) resistance may unduly increase due to interference of a flow of the exhaust gas flowing in the main exhaust path with a flow of the exhaust gas flowing toward the EGR path.

[0005] FR 2 983 521 A3 discloses a catalytic converter and an engine equipped with it. The catalytic converter is housed in a cylindrical housing and has a connection for the extraction of EGR gas on a downstream side.

[0006] FR 2 923 535 A1 discloses a particulate filter for an engine with exhaust gas recirculation.

[0007] FR 2 944 061 A1 discloses a particulate filter for a motor vehicle.

[0008] US 2012 / 0 198 838 A1 describes an exhaust gas treatment device for use near an engine.

[0009] WO 2013 / 054 711 A1 describes an exhaust gas recirculation device for an internal combustion engine.

[0010] Accordingly, it is an object of the present invention to provide an exhaust device of an engine provided with the EGR, which can properly suppress an increase in flow resistance by reducing flow interference of the exhaust gas.

[0011] This object is solved by the features of the independent claims. Preferred embodiments of the present invention are the subject of the other dependent claims.

[0012] The present invention is an exhaust gas purification device for an engine, which comprises an exhaust gas purification device provided or mountable on an exhaust path of the engine and a purification device body for purifying exhaust gas discharged from the engine, which is housed in a casing thereof, wherein the exhaust gas purification device has a GPF (Gasoline Particulate Filter) as an exhaust gas purification device, and an EGR device connected to a downstream side in an exhaust gas flow direction of the exhaust gas purification device and recirculates a part of the exhaust gas passing through the purification device body as EGR gas to an intake system of the engine, wherein an exhaust gas discharge port is provided at a downstream end portion of the casing of the exhaust gas purification device at a positionwhich is offset from a central axis of the purifier body, an EGR gas extraction port is provided at the downstream end portion of the casing of the exhaust gas purifier at a position substantially offset from the central axis of the purifier body on an opposite side to the exhaust gas discharge port, and the EGR device is provided substantially on the same side as the EGR gas extraction port relative to the central axis of the purifier body, and wherein an EGR gas extraction pipe is connected to the EGR gas extraction port of a tip portion of an EGR gas introduction portion which protrudes toward a side of the GPF toward an opposite side to an arrangement side of an exhaust gas discharge pipe,and the EGR gas extraction pipe extends from the EGR gas extraction port toward an engine body side on the GPF side parallel to the central axis of the purifier body of the GPF.,

[0013] According to the present invention, the EGR gas can be taken out from the downstream side of the exhaust gas purifying device, suppressing the interference with the exhaust gas flow to the exhaust gas discharge port, so that the increase of the flow resistance can be properly suppressed and also a piping arrangement of the EGR device can be made compact accordingly.

[0014] In one embodiment of the present invention, a downstream portion of an L-shaped exhaust pipe configured to be bent in an L-shape is connected to an upstream side in the exhaust gas flow direction of the exhaust gas purifying device, and / or the EGR gas discharge port on an outer peripheral side of an L-shaped bend of the L-shaped exhaust pipe is offset from the central axis of the purifying device body.

[0015] In this case, when the exhaust gas passes through the L-shaped exhaust pipe, a quantity of exhaust gas flows into the exhaust gas purifying device, passing through the outer peripheral side of the L-shaped bend of the L-shaped exhaust pipe due to its inertia. Accordingly, the amount of exhaust gas flowing through a portion corresponding to the outer peripheral side of the L-shaped bend of the exhaust gas purifying device is large. In contrast, since the EGR gas extraction port on the outer peripheral side of the L-shaped bend is offset from the central axis of the purifying device body, that is, on a side where the flow amount of exhaust gas from the exhaust gas purifying device is large, the exhaust gas easily flows to the EGR gas extraction port. Accordingly, the EGR performance can be properly ensured.

[0016] In another embodiment of the present invention, the exhaust device of the engine further comprises an upstream-side exhaust gas purification device connected to an upstream portion of the L-shaped exhaust pipe, wherein a downstream portion of the upstream-side exhaust gas purification device is configured to overlap a portion of an upstream-side end surface of the exhaust gas purification device when viewed in an axial direction of the exhaust gas purification device.

[0017] The exhaust gas purification device provided on the downstream side of the above-described upstream exhaust gas purification device will be referred to as the downstream exhaust gas purification device. Herein, the above-described structure in which the upstream exhaust gas purification device is connected to the upstream portion of the L-shaped exhaust pipe and the downstream portion of the upstream exhaust gas purification device is configured to overlap the upstream end face portion of the downstream exhaust gas purification device means a structure in which the downstream portion of the upstream exhaust gas purification device overlaps the upstream end face portion of the downstream exhaust gas purification device on an inner periphery side of the L-shaped bend of the L-shaped exhaust pipe, that is,on a side where the exhaust gas discharge opening or the exhaust gas discharge port is provided or made available.

[0018] In the downstream-side exhaust gas purifying device, the exhaust gas does not easily flow into the portion of its upstream-side end surface which overlaps the upstream-side exhaust gas purifying device. However, the upstream-side exhaust gas purifying device and the downstream-side exhaust gas purifying device overlap each other on the exhaust gas discharge port side, where a larger amount of exhaust gas flows out compared to the EGR gas extraction port. Accordingly, a large amount of exhaust gas flowing toward the exhaust gas discharge port flows into a portion (a so-called shadow portion) of the downstream-side exhaust gas purifying device where the upstream-side exhaust gas purifying device overlaps. That is, since the above-described portion (shadow portion) of the downstream-side exhaust gas purifying device is also referred to as the exhaust gas purifying portion.Exhaust gas purification section works effectively despite a partial overlap of the two exhaust gas purification devices as described above, a use (utilization) efficiency of the downstream exhaust gas purification device does not decrease greatly.

[0019] Therefore, according to this embodiment, the exhaust device can be made appropriately compact as a whole by the above-described overlapping of the two exhaust gas purifying devices, properly suppressing the decrease in the use efficiency of the downstream exhaust gas purifying device.

[0020] In one embodiment of the present invention, the exhaust gas purification device is provided or mountable inside an engine compartment of a motor vehicle, the EGR gas extraction port is provided below a center of the downstream end portion of the casing of the exhaust gas purification device, and / or an EGR path of the EGR device is configured to extend substantially upward from a base end side thereof connected to the EGR gas extraction port to a tip side thereof connected to the intake system.

[0021] According to this embodiment, condensed water generated inside the EGR path can be prevented from remaining.

[0022] In one embodiment of the present invention, a space portion having a bottom portion positioned below the EGR gas discharge port is formed inside the casing at a position located on a downstream side of the purifier body.

[0023] According to this embodiment, even if the condensed water generated inside the EGR path flows backward into the casing of the exhaust gas purifying device, this water can be prevented from remaining in the space portion, so that the EGR gas discharge port is closed with the remaining water, and this condensed water can be discharged from the exhaust gas discharge port.

[0024] In one embodiment of the present invention, the exhaust device further comprises a first support member connecting the casing of the exhaust gas purification device and an EGR pipe constituting the EGR path, and / or a second support member supporting a portion of the EGR pipe disposed between the EGR gas extraction port and a connecting portion where the first support member is connected.

[0025] According to this embodiment, the exhaust gas purification device can be supported by the second support member via the EGR pipe and the first support member.

[0026] In one embodiment of the present invention, the engine is an in-line multi-cylinder engine, and the exhaust gas purifying device is provided such that the central axis of the purifying device body is substantially vertical to a cylinder row direction of the engine and is offset on an arrangement side of the EGR device from a central position in the cylinder row direction of the engine.

[0027] According to this embodiment, the EGR path extending from the EGR gas extraction port provided at the downstream end portion of the exhaust gas purification device to the intake system of the engine can be arranged along one end portion in the cylinder row direction of the engine body, so that the EGR path can be made simple accordingly.

[0028] Herein, in the present specification, an expression of "being substantially vertical to a cylinder bank direction of the engine" means "having an angle of about 80 - about 100° relative to the cylinder bank direction of the engine".

[0029] According to a further aspect, a method of forming an exhaust device for an engine is provided, comprising the steps of: Providing an exhaust gas purification device, wherein the exhaust gas purification device comprises a GPF (gasoline particulate filter) as an exhaust gas purification device, Connecting an EGR device to a downstream side in an exhaust gas flow direction of the exhaust gas purification device, Forming an exhaust gas discharge opening at a downstream end portion of a casing or housing of the exhaust gas purifying device at a position offset from a central axis of a purifying device body, Forming an EGR gas extraction opening at the downstream end portion of the casing of the exhaust gas purifying device at a position which is offset substantially on an opposite side to the exhaust gas discharge opening from the central axis of the purifying device body, Providing the EGR device on the same side as the EGR gas extraction port relative to the central axis of the purifier body, and Connecting an EGR gas extraction pipe to the EGR gas extraction port of a tip portion of an EGR gas introduction portion which projects toward a side of the GPF toward an opposite side to an arrangement side of an exhaust gas discharge pipe, wherein the EGR gas extraction pipe extends from the EGR gas extraction port toward an engine body side on the GPF side parallel to the central axis of the purifier body of the GPF.

[0030] Preferably, a downstream portion of an L-shaped exhaust pipe formed to be bent in an L-shape is connected to an upstream side in the exhaust gas flow direction of the exhaust gas purifying device and / or the EGR gas discharge port on an outer peripheral side of the L-shaped bend of the L-shaped exhaust pipe is offset from the central axis of the purifying device body.

[0031] Further preferably, the method comprises the step of connecting an upstream-side exhaust gas purification device to an upstream portion of the L-shaped exhaust pipe, wherein a downstream portion of the upstream-side exhaust gas purification device is formed to overlap a portion of an upstream-side end surface of the exhaust gas purification device when viewed in an axial direction of the exhaust gas purification device.

[0032] Other features, aspects and advantages of the present invention will become apparent from the following descriptions which refer to the accompanying drawings. Fig. 1 is a perspective view of an engine provided with an exhaust device according to a first embodiment. Fig. 2 is a side view showing a part of the exhaust device. Fig. 3 is a plan view showing the part of the exhaust device. Fig. 4 is a perspective view of the part of the exhaust device when viewed from an upper left rear side. Fig. 5 is a rear view of the exhaust device. Fig. 6 is a sectional view taken along a line VI-VI of Fig. 2. Fig. 7 is a view of a downstream end portion of a casing of a gasoline particulate filter (GPF) when viewed from an upstream side.

[0033] Embodiments of the present invention will be described specifically below with reference to the drawings. The following descriptions of the preferred embodiments illustrate the present invention essentially by way of example, which in no way serves to restrict or limit the applications or uses of the present invention. MODEL 1< Engine >

[0034] An engine to which an exhaust device 1 according to a first embodiment is applied is an inline four-cylinder gasoline engine (inline multi-cylinder engine) installed on a motor vehicle. The engine is arranged laterally at a front portion of a front-engine, front-wheel drive (FF) vehicle.

[0035] Herein, the present invention is applicable not only to this four-cylinder gasoline engine, but also to any other multi-cylinder engine or a diesel engine. Furthermore, the present exhaust device 1 is applicable not only to the FF vehicle, but also to any vehicle of a different layout type, such as a rear-engine rear-wheel drive (RR) vehicle or a four-wheel drive (4WD) vehicle, including a motorcycle.

[0036] The engine has an engine body E which includes a cylinder block E1 and a cylinder head E2, as shown in Fig. 1. While detailed illustrations are omitted here, first to fourth cylinders, which are formed by the cylinder block E1 and the cylinder head E2, are arranged in series in a direction vertical to a paper surface. A combustion chamber of each cylinder is formed by a cylinder bore (not illustrated) of the cylinder block E1, a piston (not illustrated) disposed inside the cylinder bore, and the cylinder head E2.

[0037] Four exhaust ports (not illustrated), each connected to the four combustion chambers, are formed on the cylinder head E2. Exhaust gas generated inside the combustion chambers is discharged to the outside of the vehicle through an exhaust path including these exhaust ports. < Exhaust path >

[0038] As this is Fig. 1 and Fig. As shown in Fig. 2, the exhaust device 1 according to the present embodiment is connected to the above-described exhaust ports, and a downstream exhaust system (not illustrated) connecting to the vehicle exterior is connected to a downstream side of the exhaust device 1. Thus, an exhaust path of the engine includes the above-described exhaust ports, the exhaust device 1, and the downstream exhaust system. < Exhaust device >

[0039] The exhaust device 1 according to the present embodiment comprises, as shown in Fig. 1-3, an exhaust manifold M connected to the four exhaust ports of the engine body E, an exhaust gas purifying device Q connected to an outlet M7 at the downstream end of the exhaust manifold M via a connecting portion N, and an EGR device W for recirculating a part of the exhaust gas that has passed through the exhaust gas purifying device Q to an intake system. < Exhaust manifold and connecting section >

[0040] The exhaust gas discharged from four combustion chambers of the engine through the exhaust ports is supplied from the exhaust manifold M to the exhaust gas purification device Q via the connecting portion N. As shown in Fig. As shown in Figures 3-5, respective independent exhaust pipes connected to the four exhaust ports and a manifold disposed on one end side in a cylinder row direction are provided. This manifold, to which the four independent exhaust pipes are connected, extends substantially downward.

[0041] The connecting portion N is a tubular member which introduces the exhaust gas from the collecting pipe of the exhaust manifold or distributor M into the exhaust gas purification device Q. < Direction >

[0042] A “vertical direction” and a “longitudinal direction” used in the present specification are as defined in Fig. 2 is defined based on the directions where the cylinder head E2 is positioned on an upper or upward side of the engine body E, the cylinder block E1 is positioned on a lower or downward side of the engine body E, and the exhaust manifold M is positioned on a rear side of the engine body E. Furthermore, a “lateral direction” as shown in Fig. 3, a direction of a cylinder row of the engine body E, in other words a direction vertical to the paper surface of Fig. 2, where a near side means a left side and a far side means a right side. Furthermore, "upstream" and "downstream" may respectively mean "upstream side in the flow direction of the exhaust gas discharged from the combustion chamber through the exhaust port" and "downstream side in the flow direction of the exhaust gas discharged from the combustion chamber through the exhaust port."

[0043] Herein, in the present embodiment, a “longitudinal direction” is parallel to a central axis L3 of a gasoline particulate filter 3 (hereinafter referred to as “GPF 3”) which will be described later. < Exhaust gas purification device >

[0044] The exhaust gas purification device Q comprises, as shown in Fig. 3 - 5, a three-way catalyst 2 as an upstream side exhaust gas purifying device connected to the outlet of the connecting portion N, a GPF (gasoline particulate filter) 3 as a downstream side exhaust gas purifying device arranged on the downstream side of the three-way catalyst 2, and an L-shaped exhaust pipe 4 connecting the three-way catalyst 2 and the GPF 3. < Three-way catalyst >

[0045] The three-way catalyst 2 is a catalyst for purifying hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxide (NOx) in exhaust gases. While specific descriptions are omitted here, the three-way catalyst 2 is manufactured by coating a catalyst component formed by supporting a noble metal such as Pt, Pd, or Rh on a support made of a metal oxide onto a honeycomb carrier. The three-way catalyst 2 is not particularly limited thereto, but any known type is applicable.

[0046] As this is Fig. As shown in Fig. 6, the three-way catalyst 2 is a cylindrical catalyst having a central axis L2. The shape of the three-way catalyst 2 is not particularly limited, but the cylindrical shape is preferable when disposing it in the exhaust path and providing a uniform exhaust gas flow. A shape of a cross section of the three-way catalyst 2, which is vertical to the central axis L2, is not particularly limited, but any shape such as a completely round shape, an oval shape, a rectangular shape, or a polygonal shape is applicable. However, the completely round shape or the oval shape may be preferable in order to provide the uniform flow of the exhaust gas and reduce manufacturing costs.

[0047] As this is Fig. As shown in Fig. 6, a catalyst body of the three-way catalyst 2, which performs exhaust gas purification, includes an upstream end surface 2A and a downstream end surface 2B. The upstream end surface 2A of the catalyst body and the downstream end surface 2B of the catalyst body are sometimes referred to as the upstream end surface 2A of the three-way catalyst 2 and the downstream end surface 2B of the three-way catalyst 2 for convenience. The two end surfaces 2A, 2B have a circular shape having the same diameter.

[0048] The three-way catalyst 2 has a two-stage structure including a front-stage part 21 located on the upstream side and a rear-stage part 22 located on the downstream side as the catalyst body. The front-stage part 21 is a three-way catalyst excellent in low-temperature activity for purifying low-temperature exhaust gas during low-load operation of the engine body E. The rear-stage part 22 is a three-way catalyst excellent in high-temperature activity for purifying high-temperature exhaust gas during high-load operation.While the catalyst 2 is the two-stage structure including the front-stage part 21 and the rear-stage part 22 according to the present embodiment, any type of catalyst structure such as a single catalyst structure or a three- or multi-divided structure is applicable.

[0049] Furthermore, the three-way catalyst 2 includes a mat 23 covering an outer periphery of the front stage part 21 and the rear stage part 22 as the catalyst body, and a cylindrical shell 24 covering an outer periphery of the mat 23.

[0050] The exhaust gas temperature is approximately 400°C during light-load engine operation, while it is approximately 800°C during heavy-load engine operation. Accordingly, the three-way catalyst 2 is always disposed toward the high-temperature exhaust gas that has passed through the three-way catalyst 2, so there is a concern that the three-way catalyst 2 may deteriorate due to heat damage.

[0051] The mat 23 stably holds the front stage part 21 and the rear stage part 22 as the catalyst body even under an environment where the catalyst body is exposed to the high temperature exhaust gas, and this mat 23 is made of a material having high heat resistance properties and heat retention properties, such as ceramics.

[0052] The casing or housing 24 holds the catalyst body (the front stage part 21 and the rear stage part 22) and the mat 23, and this casing 24 is made of a metal such as stainless steel or iron. Any other known material can be used for the mat 23 and the casing 24. < Gasoline Particulate Filter GPF >

[0053] As this is Fig. As shown in Fig. 6, the GPF 3 is arranged on the downstream side of the three-way catalyst 2, which includes a filter body (purifier body) 33 for trapping particulate matter (hereinafter referred to as "PM") in the exhaust gas passing through the three-way catalyst 2. While specific descriptions are omitted here, the filter body 33 is manufactured by applying sealing to the honeycomb support or the like and adding the filtering performance, for example, or it may have a catalyst coating for promoting combustion of the trapped PM.When the PM contained in the exhaust gas is trapped on a dividing wall of the filter 33 and the PM accumulates, a post injection in which fuel is injected into a combustion chamber in an expansion stroke of the engine to increase the temperature of the filter body 33 is performed after a main injection in which fuel is injected into the combustion chamber for, for example, obtaining power, thereby burning and removing the PM accumulated on the filter body 33. The filter body 33 is not limited to the structure described above, but any known structure is applicable.

[0054] As this is Fig. 3, the filter body 33 is a cylindrical member having a central axis L3. The shape of the filter body 33 is not particularly limited, but the cylindrical shape is preferable for easily disposing the filter body 33 in the exhaust path and providing a smooth flow of the exhaust gas. A shape of a cross section of the filter body 33, which is substantially vertical to the central axis L3, is not particularly limited, and any shape such as a completely round shape, an oval shape, a rectangular shape, or a polygonal shape is applicable. However, the completely round shape or the oval shape is preferable for providing the smooth flow of the exhaust gas and reducing manufacturing costs.

[0055] As this is Fig. As shown in Fig. 6, the filter body 33 of the GPF 3 includes an upstream end surface 3A and a downstream end surface 3B. The upstream end surface 3A of the filter body 33 and the downstream end surface 3B of the filter body 33 are sometimes referred to as the upstream end surface 3A of the GPF 3 and the downstream end surface 3B of the GPF 3 for convenience. The two end surfaces 3A, 3B have a circular shape having the same diameter.

[0056] As this is Fig. 3 and Fig. 6, a point located on the central axis L3 of the GPF 3 at an intermediate position between the upstream end face 3A and the downstream end face 3B of the GPF 3 is referred to as a GPF center O3. The central axis L3 of the GPF 3 is the central axis of the filter body 33. Herein, a projection line and a projection point of the central axis L3 of the center O3 of the GPF 3 on the VI-VI cross section are respectively designated by reference symbols PRL31, PRO3 in Fig. 6 (a sectional view taken along a line VI-VI of Fig. 2).

[0057] Herein is how this is done in Fig. 3, the GPF 3 is arranged laterally such that the central axis L3 extends substantially in a horizontal axis, substantially vertical to the cylinder row direction of the engine body E, ie, to the lateral direction. Furthermore, the GPF 3 is provided such that the central axis L3 is offset on the end side in the cylinder row direction (on the left-hand side) from the central position in the cylinder row direction of the engine body E (a reference symbol LE in Fig. 3 denotes a line passing through the central position and normal to the cylinder row direction).

[0058] Similar to the three-way catalyst 2, the GPF includes the filter body 33, a mat 34 covering an entire part of an outer periphery of the filter body 33, a tubular shell 35 covering an entire part of an outer periphery of the mat 34, and a downstream cover 7 covering the downstream end surface 3B of the filter body 33 with a space of a gap. The tubular shell 35 and the downstream cover 7 constitute a GPF shell and a GPF housing, respectively, which houses the filter body 33. The mat 34 and the tubular shell 35 are used for the same purpose as the mat 23 and the shell 24 of the above-described three-way catalyst 2, and the same structure is applicable. < L-shaped exhaust pipe >

[0059] The L-shaped exhaust pipe 4 is a tubular member formed into an L-shaped bent shape and connecting the three-way catalyst 2 and the GPF 3, which forms a portion of the exhaust path.

[0060] As this is Fig. 6, the L-shaped exhaust pipe 4 includes an upstream-side opening 4A, a downstream-side opening 4B, and a bending portion 4C positioned between the two openings 4A, 4B. The bending portion 4C includes a first tubular portion 4C1 extending substantially in the cylinder row direction (downstream side) from the upstream-side opening 4A, a second tubular portion 4C2 extending toward the engine body from the downstream-side opening 4B, and a bending portion 4C3 connecting the first tubular portion 4C1 and the second tubular portion 4C2. The bending portion 4C3 includes an outer peripheral side bending portion 4C31 positioned on an outer peripheral side of the L-shaped bend, and an inner peripheral side bending portion 4C32 positioned on an inner peripheral side.side of an inner circumference of the L-shaped bend.

[0061] As this is Fig. 6, a downstream portion of the three-way catalyst 2 is inserted into the L-shaped exhaust pipe 4 through the upstream side opening 4A. On the other hand, an upstream end portion of the GPF 3 is inserted into the L-shaped exhaust pipe 4 through the downstream side opening 4B. - Relative arrangement of three-way catalyst and GPF -

[0062] As this is Fig. As shown in Fig. 6, the downstream end surface 2B of the three-way catalyst 2 and the upstream end surface 3A of the GPF 3 are provided such that an angle α between two surfaces is about 90 degrees at the bending portion 4C. This two-surface angle α is not limited to this angle, but for sufficiently ensuring the exhaust gas flow from the three-way catalyst 2 to the GPF 3, an angle of about 60 to about 120 degrees is preferable, an angle of about 70 to about 110 degrees is more preferable, and an angle of about 80 to about 100 degrees is particularly preferable.

[0063] In addition, the three-way catalyst 2 and the GPF 3 are provided such that the downstream portion of the three-way catalyst 2 overlaps a portion of the upstream end surface of the GPF 3 when viewed in the axial direction of the GPF 3. That is, an overlap portion 31 is formed on the three-way catalyst 2 and the GPF 3.

[0064] Fig. 6 is a sectional view taken along a line VI-VI of Fig. 2, which shows a cross section containing the central axis L2 of the three-way catalyst 2 and parallel to the central axis L3 of the GPF 3 when viewed from the upper or upward side. The cross section shown in Fig. 6 will be referred to as “VI-VI cross section” (cross section). As shown in Fig. 6, a length H31 of the side surface of the three-way catalyst 2 forming the overlap portion 31 relative to a total length H2 of the three-way catalyst 2 is preferably about 10 to about 50% in the VI-VI cross section for compactly arranging the three-way catalyst 2 and the GPF 3 and for unifying an exhaust gas flow inside the GPF 3.

[0065] Furthermore, the length H31 of the side surface of the three-way catalyst 2 relative to a width W3 of the GPF 3 is preferably about 10 to about 50% in the VI-VI cross section of Fig. 6 for compactly arranging the three-way catalyst 2 and the GPF 3 and for unifying the exhaust gas flow inside the GPF 3.

[0066] Thus, by providing the overlap portion 31 of the three-way catalyst 2 and the GPF 3 in a case where the three-way catalyst 2 and the GPF 3 are alternately arranged in the lateral direction, the distance between a position below the exhaust manifold M and the GPF 3 can be properly made short. Furthermore, by controlling (limiting) an area where the overlap portion 31 is provided within the above-described range, the exhaust device 1 can be properly compact, and utilization efficiency of the GPF 3, particularly a portion of the GPF 3 positioned behind the overlap portion 31, can also be properly improved. - First pipe link and second pipe link -

[0067] The L-shaped exhaust pipe 4 comprises, as shown in Fig. 6, a first pipe member 40 and a second pipe member 41 are connected to each other, with a connecting line thereof provided on a substantially vertical surface extending around the center of the downstream opening 4B. This connecting line extends close to and on the downstream side of the downstream end surface 2B of the three-way catalyst 2.

[0068] The first tubular member 40 constitutes or forms the upstream opening 4A, and the downstream opening 4B is constituted or formed by connecting the first tubular member 40 and the second tubular member 41. Specifically, the first tubular member 40 constitutes or forms the upstream opening 4A and a part of the downstream opening 4B and a part of the bent portion 4C, including the bent portion 4C32 on the inner peripheral side. The second tubular member 41 constitutes the remaining part of the downstream opening 4B and the remaining part of the bent portion 4C, including the bent portion 4C31 on the outer peripheral side.

[0069] Since the L-shaped exhaust pipe 4 is constituted by the first pipe member 40 and the second pipe member 41, the L-shaped exhaust pipe 4 is formed lightly. Furthermore, since the bending portion 4C32 on the inner peripheral side, which is easy to concentrate stress and has a small radius of curvature, is constituted by the first pipe member 40, that is, the connecting line is provided, avoiding a portion where stress is easily concentrated, the durability of the L-shaped exhaust pipe 4 can be properly ensured. - First wall section and second wall section -

[0070] The L-shaped exhaust pipe 4 comprises, as shown in Fig. 6, a first wall portion 42 and a second wall portion 43, which guides the exhaust gas passing through the three-way catalyst 2 to the GPF 3. The first wall portion 42 faces the downstream end surface 2B of the three-way catalyst 2, and the second wall portion 43 faces the upstream end surface 3A of the GPF 3 and forms the bent portion 4C31 on the outer peripheral side.

[0071] The first wall portion 42 and the second wall portion 43 are provided on the second pipe member 41, which constitutes the L-shaped exhaust pipe 4. Accordingly, a smooth wall surface without any connecting line can be formed by the first wall portion 42 and the second wall portion 43, so that turbulence of the exhaust flow can be properly suppressed.

[0072] The first wall portion 42, which faces the downstream end face 2B of the three-way catalyst 2, comprises, as shown in Fig. 6, an upstream-side wall portion 42C constituting the downstream-side opening 4B, a downstream-side wall portion 42A contiguous with the bent portion 4C31 on the outer peripheral side, and an inclined wall portion 42B smoothly connecting the two wall portions 42A, 42C. The upstream-side wall portion 42C protrudes toward the three-way catalyst 2 beyond the downstream-side wall portion 42A. In other words, the downstream-side wall portion 42A is configured to be a step portion that is recessed outward. These wall portions 42A, 42B, 42C constitute a part of the second tubular portion 4C2.

[0073] Since the upstream-side wall portion 42C protrudes beyond the downstream-side wall portion 42A toward the three-way catalyst 2, the exhaust gas that has passed through the three-way catalyst 2 and reached the upstream-side wall portion 42C tends to flow toward the central side of the upstream-side end face 3A of the GPF 3. That is, the exhaust gas flow is prevented from concentrating on a portion of the GPF 3 corresponding to an outer peripheral side of the L-shaped bend of the L-shaped exhaust pipe 4, so that the exhaust gas flow is induced toward the portion (shadow portion) positioned behind the overlap portion 31 of the GPF 3.

[0074] As this is Fig. 6 is a seat portion 47 where an upstream exhaust gas extraction portion 81 of a pressure difference detector 8, which is shown in Fig. 2 and will be described later, is provided on the downstream side wall portion 42A, and an exhaust gas extraction port 47A for pressure detection is formed on the seat portion 47.

[0075] As shown by arrows with a continuous line in Fig. 6, the exhaust gas passing through the three-way catalyst 2 flows while swirling upward along a wall surface of the first wall portion 42, and then flows into the GPF 3 from the L-shaped exhaust pipe 4. Since the downstream-side wall portion 42A of the L-shaped exhaust pipe 4 is farther away from the three-way catalyst 2 than the upstream-side wall portion 42C, a flow velocity of the exhaust gas near the downstream-side wall portion 42A is low. Accordingly, since the exhaust gas is taken out from the upstream-side exhaust gas taking out portion 81 arranged at the seat portion 47 of the downstream-side wall portion 42A, the pressure of the exhaust gas on the upstream side of the GPF 3 can be stably detected without greatly receiving an influence of the exhaust gas flow.

[0076] Here, any control device of various sensors or the like other than the upstream exhaust gas sampling section 81 may be arranged on the seat section 47. This ensures stable detection accuracy. < Downstream end section of the GPF >

[0077] As this is Fig. 6 and Fig. As shown in Fig. 7, at a downstream end portion 7 of the GPF 3, an exhaust gas discharge port 71 for introducing the exhaust gas passing through the GPF 3 into the exhaust gas discharge pipe 5 and an EGR gas extraction port 70 for supplying a portion of the exhaust gas to the engine intake system as the EGR gas are provided. An EGR gas extraction pipe 6 is connected to the EGR gas extraction port 70 via an EGR gas introduction portion 72A. < Exhaust gas discharge pipe >

[0078] The exhaust gas discharge pipe 5 guides the exhaust gas passing through the GPF 3 to a downstream exhaust system and retains and discharges water accompanied by the purification of the exhaust gas by the three-way catalyst 2 and the GPF 3.

[0079] A line designated by a reference PRL31 in Fig. 6 (a sectional view taken along a line VI-VI of Fig. 2) is a projection line of the central axis L3 onto the VI-VI cross section. Furthermore, a line designated by a reference symbol L5 indicates a central axis of the exhaust gas discharge pipe 5. A point designated by a reference symbol P5 is the one on the central axis L5 of the exhaust gas discharge pipe 5 and indicates a center of an inlet of the exhaust gas discharge pipe 5.

[0080] As this is Fig. 6, a center of the exhaust gas discharge port 71 on the three-way catalyst 2 side is offset from the projection line PRL31 of the central axis L3 of the GPF 3. While, in contrast, the center P5 of the inlet of the exhaust gas discharge pipe 5 is also offset from the projection line PRL31 of the central axis L3 of the GPF 3 on the three-way catalyst 2 side.

[0081] According to this structure, there occurs a flow of the exhaust gas flowing into the GPF 3 directed toward the exhaust outlet pipe 5 as shown by solid line arrows in Fig. 6. According to this exhaust gas flow directed toward the exhaust pipe 5, the amount of exhaust gas flowing into the portion (shadow portion) positioned behind the overlap portion 31 increases. This can improve the utilization efficiency of the GPF 3.

[0082] Herein, the offset amount of the center P5 of the exhaust gas discharge pipe 5 may preferably be set such that a surface 5A on the right side of the exhaust gas discharge pipe 5 positioned on the three-way catalyst 2 side is located on the rightward side, that is, on the three-way catalyst 2 side, of a GPF side surface 3C of the GPF 3 positioned on the three-way catalyst 2 side on the VI-VI cross section from aspects of improving the usage efficiency of the GPF 3 by sufficiently ensuring the amount of the exhaust gas flowing into the portion positioned behind the overlap portion 31.In this case, from aspects of suppressing an increase in flow resistance around the exhaust gas discharge pipe 5, it is preferable that the offset amount of the exhaust gas discharge pipe 5 is set so that a surface 5B of the left side of the exhaust gas discharge pipe 5, which is positioned on the leftward side, is arranged on the leftward side of the GPF side surface 3C of the GPF 3, which is positioned on the three-way catalyst 2 side on the VI-VI cross section. < EGR device >

[0083] The exhaust device 1 includes the EGR device W for recirculating a part of the exhaust gas to the intake system of the engine for the purpose of preventing the occurrence of knocking and / or reducing the amount of nitrogen oxide NOx.

[0084] The EGR device W comprises, as shown in Fig. 1, Fig. 3 and Fig. 4, the EGR gas sampling pipe 6 (EGR path), a first EGR pipe 62 (EGR path) connected to the EGR gas sampling pipe 6, an EGR cooler 63 (EGR path) connected to the first EGR pipe 62, and a second EGR pipe 64 (EGR path) connected to the EGR cooler 63. The second EGR pipe 64 is connected to a passage of the engine intake system, and an EGR valve 65 for adjusting the circulation amount of the EGR gas is provided at this connecting portion.

[0085] As this is Fig. 6, a center of the EGR gas extraction port 70 on an opposite side to the exhaust gas discharge port 71 is offset from the projection line PRL31 corresponding to the central axis L3 of the GPF 3. The EGR gas extraction pipe 6 is connected to an EGR gas introduction port 72 of a tip portion of the EGR gas introduction portion 72A, which protrudes toward one side of the GPF 3 (toward an opposite side to an arrangement side of the exhaust gas discharge pipe 5). The EGR gas extraction pipe 6 extends from the EGR gas introduction port 72 toward the engine body side on the GPF 3 side in parallel with the central axis of the GPF 3 and is bent toward the GPF 3 side, being spaced apart from the GPF 3, and adjacent to the first EGR pipe 62.

[0086] This allows, as indicated by arrows with a continuous line in Fig. 6, when the exhaust gas discharged from the three-way catalyst 2 passes through the L-shaped exhaust pipe 4, the EGR gas can be extracted in an inertial direction of the exhaust gas. Accordingly, a sufficient amount of EGR gas can be ensured. Furthermore, the EGR can be extracted while suppressing mutual interference with the exhaust flow to the exhaust discharge pipe 5. Moreover, the exhaust flow in the GPF 3 can be laterally distributed and uniformed, so that the utilization efficiency, function, and performance of the GPF 3 can be further improved.

[0087] A seat portion 77 where the downstream exhaust gas extraction port 77A opens is provided at a portion between the exhaust gas discharge port 71 and the EGR gas extraction port 70 on the downstream cover 7 of the GPF 3, and a downstream exhaust gas extraction portion 82 of the pressure difference detector 8, which will be described later, is provided at this seat portion 77. The flow of the exhaust gas is branched into one side of the exhaust gas discharge port 71 and one side of the EGR gas extraction port 70 around the seat portion 77, where the flow velocity of the exhaust gas tends to be slow and uniform. Accordingly, the pressure of the exhaust gas can be stably detected without greatly receiving an influence of the exhaust gas flow because the exhaust gas is taken out from the downstream side exhaust gas taking out portion 82 which is arranged at the seat portion 47 of the downstream side wall portion 42A.

[0088] As this is Fig. 7, a space portion 78 having a bottom portion positioned at a lower level than the EGR gas extraction port 70 is formed at a portion between the EGR gas extraction port 70 and the exhaust gas discharge port 71 and below the seat portion 77. Even if the condensed water generated in the EGR gas extraction pipe 6 flows backward, this water remains in the space portion 78, so that the EGR gas extraction port 70 and the EGR gas introduction portion 72A can be prevented from being closed with the condensed water.

[0089] As this is Fig. 2 and Fig. As shown in Fig. 4, the EGR gas extraction pipe 6 and the casing of the GPF 3 are connected by the first support member 38. The EGR gas extraction pipe 6 is supported on an engine-related component (not illustrated), such as a transmission or a power submersible device, by the second support member 61 at a portion thereof positioned between a connecting portion with the EGR gas extraction port 70 and another connecting portion with the first support member 38. Accordingly, the GPF 3 is supported on the engine-related component via the first support member 38, the EGR gas extraction pipe 6, and the second support member 61.

[0090] Furthermore, the EGR device W and the EGR gas introduction portion 72A are disposed on the outer peripheral side of the bent portion 4C31 (on the outer peripheral side or the outer peripheral side of the L-shaped bend of the L-shaped exhaust pipe 4) of the L-shaped exhaust pipe 4, and the exhaust gas discharge pipe 5, where the larger amount of exhaust gas flows compared to the EGR device W, is connected to the GPF 3 on the inner peripheral side of the bent portion 4C32 (on the inner peripheral side of the L-shaped bend) of the L-shaped exhaust pipe 4. Therefore, the exhaust gas may flow into the portion (shadow portion) located behind the overlap portion 31 as efficiently, so that the utilization efficiency of the GPF 3 increases.

[0091] Furthermore, as stated in Fig. 7, the EGR gas introduction portion 72A is positioned below a central position O7 of the downstream cover 7 of the GPF 3. Furthermore, the EGR path constituted by the EGR gas extraction pipe 6, the first EGR pipe 62, the EGR cooler 63, and the second EGR pipe 64 extends substantially upward from its base end side connected to the EGR gas introduction port 72 to its tip side connected to the engine intake system. Thereby, the condensed water generated within the EGR path can be prevented from remaining in the path.

[0092] Furthermore, since the GPF 3 is provided such that the center O3 of the GPF 3 is offset to one side (to the left) in the cylinder row direction from the central position in the cylinder row direction of the engine body E, as described above, the EGR path can be made simple accordingly. < Pressure difference detector >

[0093] The pressure difference detector 8, which is Fig. 2 is a sensor for detecting a pressure difference of the exhaust gas between the upstream side and the downstream side of the filter body 33 of the GPF 3, and the amount of PM accumulating on the filter body 33 is calculated based on the detected pressure difference.

[0094] The pressure difference detector 8 includes the upstream exhaust gas extraction section 81 which extracts the exhaust gas positioned on the upstream side of the filter body 33, the downstream exhaust gas extraction section 82 which extracts the exhaust gas positioned on the downstream side of the filter body 33, and a pressure difference sensor (pressure difference detection section) 83 which detects the pressure difference from the pressures of the exhaust gas extracted from the extraction sections 81, 82.

[0095] The upstream-side exhaust gas extraction section 81 is provided at the seat portion 47 of the L-shaped exhaust pipe 4, as described above. In contrast, the downstream-side exhaust gas extraction section 82 is provided at the seat portion 77 of the downstream cover 7 of the GPF 3, as described above. The upstream-side exhaust gas extraction section 81 and the pressure difference sensor 83 are connected by an upstream-side exhaust gas extraction pipe 81A, as shown in Fig. 2 and Fig. 4. The downstream exhaust gas sampling section 82 and the pressure difference sensor 83 are connected by a downstream exhaust gas sampling pipe 82A.

[0096] As this is Fig. As shown in Figure 2, the upstream exhaust gas sampling pipe 81A includes a sampling pipe 81A1 and another sampling pipe 81A2 connected to the sampling pipe 81A1. Furthermore, the downstream exhaust gas sampling pipe 82A includes a sampling pipe 82A1 and another sampling pipe 82A2 connected to the sampling pipe 82A1.

[0097] As this is Fig. 3, a first support member 85 is fixed to the L-shaped exhaust pipe 4, a second support member 84, which is shown in Fig. 4, is fixed to the first support member 85, and the pressure difference sensor 83 is supported on the second support member 84 via the pressure difference sensor fixing plate 83A. The second support member 84 is fixed to the cylinder block E1, as shown in Fig. 2. Since the second support member 84 is connected to the cylinder block E1 and the L-shaped exhaust pipe 4, this second support member 84 is used jointly for supporting the pressure difference sensor 83 and the L-shaped exhaust pipe 4 by the cylinder block E1.

[0098] As this is Fig.4, the pressure difference sensor 83 and the upstream-side exhaust gas sampling portion 81 are arranged on one side (on the same leftward side as a disposition side of the EGR gas sampling pipe 6) of the GPF 3. Therefore, the upstream-side exhaust gas sampling pipe 81A can be arranged on one side of the GPF 3 as the EGR gas sampling pipe 6. Further, a sampling pipe support member 81A3, which supports the upstream-side exhaust gas sampling pipe 81A, is fixed to the first support member 38 to support the GPF 3 and the EGR gas sampling pipe 6. Accordingly, the upstream-side exhaust gas sampling pipe 81A is supported by the second support member 61 to support the GPF 3 and the EGR gas sampling pipe 6. Thus, the performance of compactness and layout of the device can be improved by supporting the upstream side exhaust gas sampling pipe 81A by using the second support member 61. Other embodiments

[0099] While the exhaust device 1 of the first embodiment is applied to the FF vehicle, the present invention is applicable to an FR vehicle by configuring the exhaust device such that the independent exhaust pipes of the exhaust manifold M connected to the four exhaust ports extend substantially rearward and join together, and then extend substantially rearward on a central side in the vehicle width direction of the engine body E.

[0100] While the upstream exhaust purification device is the three-way catalyst 2 and the downstream exhaust purification device is the GPF 3 in the first embodiment, any other types of exhaust purification devices are applicable. For example, in a case where the exhaust purification device 1 is applied to the diesel engine, a diesel particulate filter is usable instead of the GPF. Furthermore, the upstream exhaust purification device may be configured as an oxidation catalyst, and the downstream exhaust purification device may be configured as a NOx purification catalyst, or the reverse is also possible.

[0101] While the downstream end outlet of the exhaust manifold M is provided on the first cylinder side in the cylinder row direction of the engine and the upstream side opening 4A of the L-shaped exhaust pipe 4 is directed to the first cylinder side in the cylinder row direction according to the first embodiment, the upstream side opening 4A may be directed to any other direction according to the layout of the vehicle, for example, to the fourth cylinder side, to the upstream side, or to the downstream side.

[0102] The exhaust device of the engine provided with an EGR device according to the present invention can properly suppress the interference with the flow of the exhaust gas discharged from the exhaust gas purifying device toward the exhaust gas discharge port, and also surely take out the EGR gas from the downstream side of the exhaust gas purifying device.

Claims

[1] Exhaust device for an engine, comprising: an exhaust gas purification device (Q) which is provided or mountable on an exhaust or exhaust path of the engine and comprises a purification device body for purifying exhaust gas discharged from the engine, which is accommodated in a casing (35) of the exhaust gas purification device (Q), wherein the exhaust gas purification device (Q) comprises a GPF (gasoline particulate filter) (3) as an exhaust gas purification device; and an EGR device (W) which is connected to a downstream side in an exhaust gas flow direction of the exhaust gas purifying device (Q) and recirculates a part of the exhaust gas passing through the purifying device body as EGR gas to an intake system of the engine, wherein an exhaust gas discharge opening (71) is provided at a downstream end portion of the casing (35) of the exhaust gas purification device (Q) at a position which is offset from a central axis (L3) of the purifier body, an EGR gas extraction opening (70) is provided at the downstream end portion of the casing (35) of the exhaust gas purifier (Q) at a position which is offset from the central axis (L3) of the purifier body on an opposite side to the exhaust gas discharge opening (71), and the EGR device (W) is provided on the same side as the EGR gas extraction opening (70) relative to the central axis (L3) of the purifier body, wherein an EGR gas extraction pipe (6) is connected to the EGR gas extraction opening (70) of a tip portion of an EGR gas introduction portion (72A) which projects toward one side of the GPF (3) toward an opposite side to an arrangement side of an exhaust gas discharge pipe (5), and the EGR gas extraction pipe (6) extends from the EGR gas extraction port (70) toward an engine body side on the GPF (3) side parallel to the central axis (L3) of the purifier body of the GPF (3). [2] The exhaust device according to claim 1, wherein a downstream portion of an L-shaped exhaust pipe (4) configured to be bent in an L-shape is connected to an upstream side in the exhaust gas flow direction of the exhaust gas purifying device (Q), and / or the EGR gas discharge port (70) on an outer peripheral side of the L-shaped bend of the L-shaped exhaust pipe (4) is offset from the central axis (L3) of the purifying device body. [3] The exhaust device according to claim 2, further comprising an upstream-side exhaust gas purification device (2) connected to an upstream portion of the L-shaped exhaust pipe (4), wherein a downstream portion of the upstream-side exhaust gas purification device (2) is configured to overlap a portion of an upstream-side end surface of the exhaust gas purification device (Q) when viewed in an axial direction of the exhaust gas purification device (Q). [4] An exhaust gas device according to any one of the preceding claims, wherein the exhaust gas purification device (Q) is configured to be provided inside an engine compartment of a motor vehicle, the EGR gas extraction port (70) is provided below a center of the downstream end portion of the casing (35) of the exhaust gas purification device (Q), and / or an EGR path of the EGR device (W) is configured to extend substantially upward from a base end side thereof connected to the EGR gas extraction port (70) to a tip side thereof connected or connectable to the intake system. [5] An exhaust device according to any one of the preceding claims, wherein a space portion having a bottom portion positioned below the EGR gas extraction port (70) is formed inside the casing (35) at a position located on a downstream side of the purifier body. [6] The exhaust device according to claim 4 or 5, further comprising a first support member (38) connecting the casing (35) of the exhaust gas purification device (Q) and an EGR pipe (62, 64) constituting the EGR path, and / or a second support member (61) supporting a portion of the EGR pipe (62, 64) disposed between the EGR gas extraction port (70) and a connecting portion where the first support member (38) is connected. [7] An exhaust device according to any one of the preceding claims, wherein the engine is an in-line multi-cylinder engine and the exhaust gas purifying device (Q) is provided such that the central axis (L3) of the purifying device body is substantially vertical to a cylinder row direction of the engine and is offset on an arrangement side of the EGR device (W) from a central position in the cylinder row direction of the engine. [8] A method of forming an exhaust device for an engine, comprising the steps of: Providing an exhaust gas purification device (Q), wherein the exhaust gas purification device (Q) has a GPF (gasoline particulate filter) (3) as an exhaust gas purification device, connecting an EGR device (W) to a downstream side in an exhaust gas flow direction of the exhaust gas purification device (Q), Forming an exhaust gas discharge opening (71) at a downstream end portion of a casing (35) of the exhaust gas purifying device (Q) at a position offset from a central axis (L3) of a purifying device body, Forming an EGR gas extraction opening (70) at the downstream end portion of the casing (35) of the exhaust gas purifying device (Q) at a position which is offset on an opposite side to the exhaust gas discharge opening from the central axis (L3) of the purifying device body, Providing the EGR device (W) on the same side as the EGR gas extraction opening (70) relative to the central axis (L3) of the purifier body, and Connecting an EGR gas extraction pipe (6) to the EGR gas extraction opening (70) of a tip portion of an EGR gas introduction portion (72A) which projects toward one side of the GPF (3) toward an opposite side to an arrangement side of an exhaust gas discharge pipe (5), wherein the EGR gas extraction pipe (6) extends from the EGR gas extraction port (70) toward an engine body side on the GPF (3) side parallel to the central axis (L3) of the purifier body of the GPF (3). [9] The method according to claim 8, wherein a downstream portion of an L-shaped exhaust pipe (4) formed to be bent in an L-shape is connected to an upstream side in the exhaust gas flow direction of the exhaust gas purifying device (Q), and / or the EGR gas discharge port (70) on an outer peripheral side of the L-shaped bend of the L-shaped exhaust pipe (4) is offset from the central axis (L3) of the purifying device body. [10] The method according to claim 9, further comprising the step of connecting an upstream-side exhaust gas purification device (2) to an upstream portion of the L-shaped exhaust pipe (4), wherein a downstream portion of the upstream-side exhaust gas purification device (2) is formed to overlap a portion of an upstream-side end surface of the exhaust gas purification device (Q) when viewed in an axial direction of the exhaust gas purification device (Q).

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