JP6436217B2 - Engine exhaust system - Google Patents

Description

  The present invention relates to an exhaust system for an engine.

  2. Description of the Related Art Conventionally, an exhaust purification device that purifies exhaust gas has been disposed in an exhaust path of an automobile engine such as a diesel engine or a gasoline engine.

  For the purpose of preventing the occurrence of knocking and reducing the amount of nitrogen oxides NOx, EGR is employed in which part of the exhaust gas that has passed through the exhaust purification device and purified is recirculated to the intake system as EGR gas. (For example, see Patent Documents 1 and 2).

JP 2004-176554 A JP 2012-031782 A

  By the way, as described in Patent Documents 1 and 2, when the EGR path is branched from the downstream side of the exhaust purification device, if the branch is made from the cone portion or the flange connected to the main exhaust path of the case of the exhaust purification device, the main exhaust path There is a risk that the ventilation resistance will increase due to the interference of the flow of the exhaust gas flowing through the exhaust gas and the flow of the exhaust gas toward the EGR path.

  Therefore, the present invention reduces the interference of the exhaust gas flow and suppresses an increase in ventilation resistance in an exhaust system for an engine equipped with EGR.

  In order to solve the above-mentioned problems, the present invention arranges an exhaust gas discharge port and an EGR gas outlet at the downstream end of the exhaust purification device so as to be biased to the opposite sides from the central axis of the exhaust purification device. I did it.

An engine exhaust device disclosed herein is disposed on an exhaust path of the engine, and an exhaust purification device in which a purification device body for purifying exhaust gas exhausted from the engine is housed in a case;
An EGR device that is connected to the exhaust gas flow direction downstream side of the exhaust gas purification device and circulates a part of the exhaust gas that has passed through the purification device main body as EGR gas to the intake system of the engine,
The downstream end of the case is provided with an exhaust gas discharge port at a position deviated from the central axis of the purification device main body, and is biased to the opposite side of the exhaust gas discharge port from the central axis of the purification device main body. EGR gas outlet is provided at the position
The EGR device is arranged on the same side as the EGR gas outlet with respect to the central axis of the purification device main body.

  According to this, it is possible to take out EGR gas from the downstream side of the exhaust purification device while suppressing interference with the exhaust gas flow to the exhaust gas discharge port, which is advantageous for suppressing increase in ventilation resistance, and for the EGR device. It is also advantageous for simplification of piping.

In one embodiment, a downstream portion of an L-shaped exhaust pipe bent in an L shape is connected to an upstream side in the exhaust gas flow direction of the exhaust purification device,
The exhaust gas outlet is biased from the central axis of the purification device main body toward the inner peripheral side of the L-shaped bend in the L-shaped exhaust pipe,
The EGR gas outlet is biased from the central axis of the purification device main body toward the outer periphery of the L-shaped bend in the L-shaped exhaust pipe.

  In this case, when the exhaust gas passes through the L-shaped exhaust pipe, due to inertia, most of the exhaust gas flows into the exhaust purification device through the outer peripheral side of the L-shaped bend in the L-shaped exhaust pipe. As a result, the exhaust gas flow rate passing through the portion corresponding to the outer peripheral side of the L-shaped bend of the exhaust purification device increases. On the other hand, since the EGR gas outlet is biased from the central axis of the purification device body to the outer peripheral side of the L-shaped curve, that is, the side where the exhaust gas flow rate of the exhaust purification device increases, EGR gas Exhaust gas can easily flow to the outlet. Therefore, it becomes advantageous for ensuring the EGR performance.

In one embodiment, an upstream side exhaust purification device connected to the upstream portion of the L-shaped exhaust pipe,
When viewed in the axial direction of the exhaust purification device, the downstream portion of the upstream exhaust purification device overlaps a part of the upstream end surface of the exhaust purification device.

  The exhaust purification device disposed on the downstream side as viewed from the upstream exhaust purification device will be described as a downstream exhaust purification device. The upstream exhaust purification device is connected to an upstream portion of an L-shaped exhaust pipe, The fact that the downstream part of the upstream side exhaust purification device overlaps with a part of the upstream end face of the downstream side exhaust purification device means that the downstream part of the upstream side exhaust purification device is L-shaped in the L-shaped exhaust pipe. This means that on the inner peripheral side of the bend, that is, on the side where the exhaust gas discharge port is disposed, it overlaps a part of the upstream end surface of the downstream side exhaust purification device.

  In the downstream side exhaust purification device, the exhaust gas is less likely to flow into the portion of the upstream end face where the upstream side exhaust purification device overlaps. However, the upstream side exhaust purification device and the downstream side exhaust purification device overlap on the exhaust gas discharge port side from which a large amount of exhaust gas flows out compared to the EGR gas outlet. Accordingly, a large amount of exhaust gas flows toward the exhaust gas discharge port even in the shadowed portion of the upstream side exhaust purification device that overlaps with the upstream side exhaust purification device. That is, as described above, although the exhaust purification devices are partially overlapped with each other, the shaded portion of the downstream exhaust purification device also works effectively for exhaust gas purification. The utilization efficiency of the purification device is not greatly reduced.

  Therefore, according to this embodiment, the exhaust system as a whole can be made compact by overlapping the exhaust purification apparatuses described above, while suppressing a decrease in the utilization efficiency of the downstream side exhaust purification apparatus.

In one embodiment, the exhaust emission control device is disposed in an engine room of an automobile,
The EGR gas outlet is disposed below the center of the downstream end of the case of the exhaust purification device,
The EGR path of the EGR device extends upward from the base end side connected to the EGR gas outlet to the front end side connected to the engine intake system.

  According to this, it is possible to suppress the condensed water generated in the EGR path from accumulating in the EGR path.

  In one embodiment, a space portion whose bottom is lower than the EGR gas outlet is formed on the downstream side of the purification device main body in the case of the exhaust purification device.

  According to this, even if the condensed water generated in the EGR path flows back into the case of the exhaust gas purification device, it can be prevented from accumulating in the space and blocking the EGR gas outlet, and the condensed water is exhausted. It can be discharged from the gas outlet.

In one embodiment, a first support member that couples the case of the exhaust emission control device and an EGR pipe constituting the EGR path;
And a second support member that supports a portion of the EGR pipe between the EGR gas outlet and a portion where the first support member is coupled.

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

In one embodiment, the engine is an in-line multi-cylinder engine,
The exhaust purification device is provided so that a central axis of the purification device main body is substantially perpendicular to a cylinder row direction of the engine, and the EGR device is disposed from a center position of the engine in the cylinder row direction of the engine. It is biased to the side where it is placed.

  According to this, the EGR path from the EGR gas outlet at the downstream end of the exhaust purification device to the intake system of the engine can be arranged along the end of the engine body in the cylinder row direction, and the EGR path is This is advantageous for simplification.

  In the present specification, “substantially perpendicular to the cylinder row direction of the engine” means “an angle of 80 degrees to 100 degrees with respect to the cylinder row direction of the engine”.

  According to the present invention, the exhaust gas discharge port and the EGR gas outlet are provided at the downstream end of the case of the exhaust purification device, and the exhaust gas discharge port is biased to one side from the central axis of the purification device main body, and the EGR gas Since the outlet is biased from the central axis of the purification device main body to the side opposite to the exhaust gas discharge port, from the downstream side of the exhaust purification device while suppressing interference with the exhaust gas flow to the exhaust gas discharge port EGR gas can be taken out, which is advantageous for suppressing an increase in ventilation resistance and is also advantageous for simplifying the piping of the EGR device.

FIG. 1 is a perspective view of an engine to which an exhaust device according to Embodiment 1 is attached. FIG. 2 is a side view showing a part of the exhaust device. FIG. 3 is a plan view showing a part of the exhaust device. FIG. 4 is a perspective view of a part of the exhaust device as viewed from the upper left rear. FIG. 5 is a rear view of the exhaust emission control device. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a view of the downstream end of the GPF case as viewed from the upstream side.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or its application.

(Embodiment 1)
<Engine>
The engine to which the exhaust device 1 according to Embodiment 1 is applied is an in-line four-cylinder gasoline engine (in-line multi-cylinder engine) mounted on an automobile. This engine is placed horizontally in front of the FF vehicle.

  The present invention can be applied not only to a four-cylinder gasoline engine but also to other multi-cylinder engines and diesel engines. Further, the present invention is not limited to FF vehicles, and can be applied to vehicles adopting various layouts including motorcycles such as RR vehicles and 4WD vehicles.

  As shown in FIG. 1, the engine includes an engine body E having a cylinder block E1 and a cylinder head E2. Although not shown in detail, the engine includes a first cylinder to a fourth cylinder configured by a cylinder block E1 and a cylinder head E2. The first to fourth cylinders are arranged in series in this order from the front of the page to the back side in a direction perpendicular to the page of FIG. A cylinder chamber (not shown) of the cylinder block E1, a piston (not shown) in the cylinder bore, and a cylinder head E2 form a combustion chamber for each cylinder.

  The cylinder head E2 has four exhaust ports (not shown) connected to the four combustion chambers. Exhaust gas generated in the combustion chamber is discharged out of the vehicle through an exhaust path including the exhaust port.

<Exhaust path>
As shown in FIGS. 1 to 3, the exhaust device 1 according to the present embodiment is connected to the exhaust port, and a downstream exhaust system (not shown) having a tail pipe is connected to the downstream side thereof. Has been. Thus, the exhaust path of the engine is constituted by the above-described exhaust port, the exhaust device 1, and the downstream exhaust system.

<Exhaust device>
The exhaust device 1 according to the present embodiment is disposed in the engine room, and as shown in FIGS. 1 to 3, an exhaust manifold M connected to four exhaust ports of the engine body E, and an exhaust manifold M The exhaust gas purification device Q is connected to the downstream end outlet M7 via the connection portion N, and the EGR device W is configured to recirculate part of the exhaust gas that has passed through the catalyst device Q to the intake system.

<Exhaust manifold and connections>
Exhaust gas discharged from the four combustion chambers of the engine through the exhaust port is sent from the exhaust manifold M to the catalyst device Q through the connection portion N. As shown in FIGS. 3 to 5, the exhaust manifold M is disposed on one end side in the cylinder row direction connected to each of the four exhaust ports and connected to the four independent exhaust pipes. A collecting pipe extending downward is provided.

  The connecting portion N is a tubular member that introduces exhaust gas from the collecting pipe of the exhaust manifold M into the exhaust purification device Q.

<Direction>
In the description of the present specification, the “vertical direction” and “front-rear direction” refer to the engine body E as a reference, the cylinder head E2 side is the upper side, the cylinder block E1 side is the lower side, and the engine body, as shown in FIG. A direction in which the E side is the front side and the exhaust manifold M side is the rear side is assumed. Further, as shown in FIG. 3, the “left-right direction” means the cylinder arrangement direction with respect to the engine body E, in other words, perpendicular to the paper surface of FIG. 2, and the front side is the left side and the back side is the right side. The direction to do. Further, “upstream” and “downstream” are referred to as “upstream side in the exhaust gas flow direction” and “downstream side in the exhaust gas flow direction” based on the flow direction of the exhaust gas discharged from the combustion chamber through the exhaust port. is there.

  In the present embodiment, the “front-rear direction” is parallel to a central axis L3 of a gasoline particulate filter 3 (hereinafter referred to as “GPF3”), which will be described later.

<Exhaust gas purification device>
As shown in FIGS. 3 to 5, the exhaust purification device Q includes a three-way catalyst 2 as an upstream side exhaust purification device connected to the outlet of the connection portion N, and a downstream side exhaust purification device disposed on the downstream side thereof. And an L-shaped exhaust pipe 4 for connecting the three-way catalyst 2 and the GPF 3 to each other.

<Three-way catalyst>
The three-way catalyst 2 is a catalyst for purifying hydrocarbon HC, carbon monoxide CO, and nitrogen oxide NOx in the exhaust gas. Although the detailed description is omitted, the three-way catalyst 2 is a catalyst formed by coating a honeycomb carrier with a catalyst component formed by supporting a noble metal such as Pt, Pd, Rh on a support material made of a metal oxide. Etc. The three-way catalyst 2 is not particularly limited, and any known catalyst can be used.

  The three-way catalyst 2 is a cylindrical catalyst having a central axis L2, as shown in FIG. The shape of the three-way catalyst 2 is not particularly limited, but is preferably a cylindrical shape from the viewpoint of being easily disposed in the exhaust path and obtaining a uniform exhaust gas flow. The shape of the cross section perpendicular to the central axis L2 of the three-way catalyst 2 is not particularly limited, and any shape such as a perfect circle shape, an ellipse shape, a rectangular shape, or a polygonal shape can be adopted. From the viewpoint of obtaining an exhaust gas flow and suppressing the manufacturing cost, it is preferably a perfect circle or ellipse.

  As shown in FIG. 6, the catalyst body for purifying the exhaust gas of the three-way catalyst 2 has an upstream end face 2A and a downstream end face 2B. For convenience, the end face 2A on the upstream side of the catalyst body and the end face 2B on the downstream side of the catalyst body may be referred to as the end face 2A on the upstream side of the three-way catalyst 2 and the end face 2B on the downstream side of the three-way catalyst 2. Both end faces 2A and 2B are circular with the same diameter.

  The three-way catalyst 2 includes a front stage portion 21 arranged on the upstream side and a rear stage portion 22 arranged on the downstream side as a catalyst body. The front stage 21 is a three-way catalyst excellent in low-temperature activity that purifies low-temperature exhaust gas during low-load operation of the engine body E. Further, the rear stage 22 is a three-way catalyst excellent in high-temperature activity that purifies high-temperature exhaust gas during high-load operation or the like. In the present embodiment, the three-way catalyst 2 has a two-stage configuration including the front stage portion 21 and the rear stage portion 22, but is not limited to this, and may have a single catalyst configuration, Further, it may be a multistage configuration divided into three or more.

  Further, the three-way catalyst 2 includes a mat 23 that covers the entire outer periphery of the front stage portion 21 and the rear stage portion 22 as a catalyst main body, and a case 24 that covers the entire outer periphery of the mat 23.

  The exhaust gas temperature is around 400 ° C. during a light load operation of the engine, and becomes a high temperature around 800 ° C. during a high load operation of the engine. Then, the three-way catalyst 2 itself is always exposed to the high-temperature exhaust gas that has passed through the three-way catalyst 2, which may cause the three-way catalyst 2 to deteriorate due to heat damage.

  The mat 23 is for stably holding the front-stage part 21 and the rear-stage part 22 as the catalyst body even in an environment exposed to high-temperature exhaust gas. For example, the mat 23 has high heat resistance and heat retention such as ceramic. It is formed with the material which has.

  The case 24 is for holding the catalyst main body (the front stage portion 21 and the rear stage portion 22) and the mat 23, and is made of a metal such as iron or stainless steel, for example. As the mat 23 and the case 24, known ones may be used.

<GPF>
As shown in FIG. 6, the GPF 3 is disposed on the downstream side of the three-way catalyst 2, and traps particulate matter (hereinafter referred to as “PM”) in the exhaust gas that has passed through the three-way catalyst 2. A filter main body (purification device main body) 33 is provided. Although the detailed description of the filter body 33 is omitted, for example, a honeycomb carrier or the like is sealed and a filter function is added, and the filter body 33 may have a catalyst coat to promote combustion of trapped PM. Good. The PM in the exhaust gas is collected in the partition wall of the filter main body 33. When the PM is deposited, for example, after the main injection in which fuel is injected into the combustion chamber of the engine to obtain output, the filter main body in the expansion stroke of the engine Post injection for injecting fuel for increasing the temperature of 33 into the combustion chamber is performed, and PM deposited on the filter main body 33 is incinerated and removed. The filter body 33 is not particularly limited, and any known filter body can be used.

  As shown in FIG. 3, the GPF 3 has a cylindrical shape having a central axis L3. The shape of the filter main body 33 is not particularly limited, but is preferably cylindrical from the viewpoint of easy disposition in the exhaust path and obtaining a uniform exhaust gas flow. The shape of the cross section perpendicular to the central axis L3 of the filter body 33 is not particularly limited, and any shape such as a perfect circle shape, an ellipse shape, a rectangular shape, or a polygonal shape can be adopted. From the viewpoint of obtaining a gas flow and reducing the manufacturing cost, it is preferably a perfect circle or ellipse.

  As shown in FIG. 6, the filter body 33 of the GPF 3 has an upstream end surface 3A and a downstream end surface 3B. For convenience, the end face 2A on the upstream side of the filter body 33 and the end face 2B on the downstream side of the filter body 33 may be referred to as the end face 2A on the upstream side of the GPF 3 and the end face 2B on the downstream side of the GPF 3. Both end surfaces 3A and 3B are circular with the same diameter.

  As shown in FIGS. 3 and 6, a point located on the central axis L3 of the GPF 3 and positioned between the upstream end surface 3A and the downstream end surface 3B of the GPF 3 is defined as a GPF center O3. The central axis L3 of the GPF 3 is the central axis of the filter body 33. In FIG. 6 (cross-sectional view taken along the line VI-VI in FIG. 2), the projection line and the projection point on the VI-VI cross section of the central axis L3 and the center O3 of GPF3 are indicated by reference signs PRL31 and PRO3, respectively.

  Here, as shown in FIG. 3, the GPF 3 is horizontally placed with the central axis L <b> 3 extending substantially in the horizontal direction so that it is substantially perpendicular to the cylinder row direction of the engine body E, that is, the left-right direction. The GPF 3 has a central axis L3 from the center position in the cylinder row direction of the engine body E (LE in FIG. 3 is a line perpendicular to the cylinder row direction through the center position), and one side in the cylinder row direction ( Left side).

  Similar to the three-way catalyst 2, the GPF 3 includes a filter main body 33, a mat 34 covering the entire outer periphery of the filter main body 33, a cylindrical case 35 covering the entire outer periphery of the mat 34, and an end face on the downstream side of the filter main body 33. And a downstream cover 7 that covers 3B with a space. The cylindrical case 35 and the downstream cover 7 constitute a GPF case that houses the filter main body 33. The mat 34 and the cylindrical case 35 are used for the same purpose as the mat 23 and the case 24 of the three-way catalyst 2 described above, and those having the same configuration can be used.

<L-shaped exhaust pipe>
The L-shaped exhaust pipe 4 is a tubular member bent in an L-shape for connecting the three-way catalyst 2 and the GPF 3 and forms a part of the exhaust path.

  As shown in FIG. 6, the L-shaped exhaust pipe 4 includes an upstream opening 4A, a downstream opening 4B, and a bent portion 4C between the openings 4A and 4B. The bent portion 4C includes a first tubular portion 4C1 extending from the upstream opening 4A in the cylinder row direction (downstream side), a second tubular portion 4C2 extending from the downstream opening 4B toward the engine body, and the first A bent portion 4C3 that connects the tubular portion 4C1 and the second tubular portion 4C2 is provided. And the bending part 4C3 is provided with the outer peripheral side bending part 4C31 located in the outer peripheral side of L-shaped bending, and the inner peripheral side bending part 4C32 located in an inner peripheral side.

  As shown in FIG. 6, the three-way catalyst 2 has a downstream portion inserted into the L-shaped exhaust pipe 4 from the upstream opening 4 </ b> A. On the other hand, the upstream end of the GPF 3 is inserted into the L-shaped exhaust pipe 4 from the downstream opening 4B.

-Relative arrangement of three-way catalyst and GPF-
As shown in FIG. 6, the end face 2B on the downstream side of the three-way catalyst 2 and the end face 3A on the upstream side of the GPF 3 are disposed so that the dihedral angle α is about 90 degrees in the bent portion 4C. . The dihedral angle α is not limited to this angle, but from the viewpoint of sufficiently securing the exhaust gas flow from the three-way catalyst 2 to the GPF 3, it is preferably 60 degrees or more and 120 degrees or less, more preferably It is 70 degrees or more and 110 degrees or less, Most preferably, they are 80 degrees or more and 100 degrees or less.

  In addition, the three-way catalyst 2 and the GPF 3 are disposed so that the downstream portion of the three-way catalyst 2 overlaps a part of the upstream end surface of the GPF 3 when viewed in the axial direction of the GPF 3. That is, an overlapping portion 31 is formed between the three-way catalyst 2 and the GPF 3.

  FIG. 6 is a view showing a VV cross section in FIG. 2, and is a view of a cross section including the central axis L2 of the three-way catalyst 2 and parallel to the central axis L3 of the GPF 3 as viewed from above. The cross section described in FIG. 6 is hereinafter referred to as “VV cross section”. As shown in FIG. 6, the length H31 of the side surface of the three-way catalyst 2 forming the overlapping portion 31 on the VV cross section is the exhaust gas in the GPF 3 while the three-way catalyst 2 and the GPF 3 are arranged in a compact manner. From the viewpoint of making the flow uniform, the total length H2 of the three-way catalyst 2 is preferably 10% or more and less than 50%.

  Further, the length H31 of the side surface of the three-way catalyst 2 is determined from the viewpoint of making the exhaust gas flow in the GPF 3 uniform while arranging the three-way catalyst 2 and the GPF 3 compactly in the VV cross section of FIG. The width W3 is preferably 10% or more and less than 50%.

  As described above, when the three-way catalyst 2 and the GPF 3 are arranged in the lateral direction, the overlapping portion 31 of the three-way catalyst 2 and the GPF 3 is formed, thereby reducing the distance from the downstream end of the exhaust manifold M to the GPF 3. Can be In addition, while forming the overlapping portion 31, by suppressing the range to less than the above range, the exhaust device 1 can be made compact, and the use efficiency of the GPF 3, particularly the portion that becomes a shadow of the overlapping portion 31, can be improved. Can be made.

-1st pipe member and 2nd pipe member-
As shown in FIG. 6, the L-shaped exhaust pipe 4 includes a first pipe member 40 and a second pipe member 41 which are joined by providing a joining line on a substantially vertical surface passing through the substantially center of the downstream opening 4 </ b> B. It is configured. The joining line is in the vicinity of the end face 2B on the downstream side of the three-way catalyst 2 and passes downstream from the end face 2B.

  The first pipe member 40 forms the upstream side opening 4 </ b> A, and the downstream side opening 4 </ b> B is formed by joining the first pipe member 40 and the second pipe member 41. Specifically, the first pipe member 40 forms the upstream opening 4A, and forms a part of the downstream opening 4B and a part including the inner peripheral side bent part 4C32 of the bent part 4C. ing. The second pipe member 41 forms a remaining portion including the remaining portion of the downstream opening 4B and the outer peripheral side bent portion 4C31 of the bent portion 4C.

  Since the L-shaped exhaust pipe 4 is formed by the first pipe member 40 and the second pipe member 41, the L-shaped exhaust pipe 4 can be easily formed. Further, since the inner circumferential side bent portion 4C32 having a small curvature radius where stress is likely to concentrate is formed by the first pipe member 40, that is, since a joining line is provided avoiding a portion where stress is likely to concentrate, an L-shaped exhaust pipe 4 is advantageous for securing the durability.

-1st wall part and 2nd wall part-
As shown in FIG. 6, the L-shaped exhaust pipe 4 includes a first wall portion 42 and a second wall portion 43 for guiding the exhaust gas that has passed through the three-way catalyst 2 to the GPF 3. The first wall portion 42 faces the end surface 2B on the downstream side of the three-way catalyst 2, and the second wall portion 43 faces the end surface 3A on the upstream side of the GPF 3 to form the outer peripheral side bent portion 4C31. doing.

  The first wall portion 42 and the second wall portion 43 are formed on one second pipe member 41 constituting the L-shaped exhaust pipe 4. Accordingly, a smooth wall surface without a joining line can be obtained by the first wall portion 42 and the second wall portion 43, which is advantageous in suppressing disturbance of the exhaust gas flow.

  As shown in FIG. 6, the first wall portion 42 facing the downstream end surface 2B of the three-way catalyst 2 includes an upstream side wall portion 42C that forms the downstream side opening 4B, and a downstream side wall portion that continues from the outer peripheral side bent portion 4C31. 42A and the inclined wall part 42B which connects both wall part 42A, 42C smoothly are provided. The upstream side wall portion 42C travels to the three-way catalyst 2 side than the downstream side wall portion 42A. In other words, the downstream side wall portion 42A is a stepped portion that is recessed outward. These wall portions 42A, 42B, and 42C constitute a part of the second tubular portion 4C2.

  Since the upstream side wall portion 42C travels closer to the three-way catalyst 2 than the downstream side wall portion 42A, the exhaust gas that has passed through the three-way catalyst 2 and reached the upstream side wall portion 42C is upstream of the GPF 3 as shown in FIG. It becomes easy to go to the center side of the side end surface 3A. That is, it is suppressed that exhaust gas concentrates on the site | part corresponding to the outer peripheral side of the L-shaped curve in the L-shaped exhaust pipe 4 in GPF3, and the exhaust gas flow toward the site | part used as the shadow of the overlap part 31 of GPF3 is produced. Induced.

  As shown in FIG. 6, the downstream side wall portion 42A is provided with a pedestal 47 on which an upstream side exhaust gas extraction portion 81 of the differential pressure detecting device 8 described later shown in FIG. For this purpose, an exhaust gas outlet 47A is opened.

  The exhaust gas that has passed through the three-way catalyst 2 flows so as to roll up along the wall surface of the first wall portion 42 as shown by the solid line arrow in FIG. 6, and flows into the PF 3 from the L-shaped exhaust pipe 4. . Since the downstream side wall portion 42A of the L-shaped exhaust pipe 4 is farther from the three-way catalyst 2 than the upstream side wall portion 42C, the flow rate of the exhaust gas in the vicinity of the downstream side wall portion 42A is low. Therefore, the pressure on the upstream side of the GPF 3 can be stably obtained without being greatly affected by the flow of the exhaust gas by taking out the exhaust gas from the upstream side exhaust gas extraction part 81 installed on the pedestal 47 of the downstream side wall part 42A. Can be detected.

  The pedestal 47 may be provided with a control device such as various sensors other than the upstream side exhaust gas extraction unit 81. Thereby, stable detection accuracy can be ensured.

<Downstream end of GPF>
As shown in FIGS. 6 and 7, the downstream cover 7 of the GPF 3 has an exhaust gas exhaust port 71 that guides the exhaust gas that has passed through the GPF 3 to the exhaust gas exhaust pipe 5, and an engine using a part of the exhaust gas as EGR gas. An EGR gas outlet 70 is provided to supply the intake system. The EGR gas outlet pipe 6 is connected to the EGR gas outlet 70 via an EGR gas inlet 72A.

<Exhaust gas exhaust pipe>
The exhaust gas discharge pipe 5 is for guiding the exhaust gas that has passed through the GPF 3 to the downstream exhaust system, and for collecting and removing moisture generated by the purification of the exhaust gas by the three-way catalyst 2 and the GPF 3.

  A line indicated by a symbol PRL31 shown in FIG. 6 (a cross-sectional view taken along the line VV in FIG. 2) is a projection line on the VV cross section of the central axis L3 of the GPF3. A line indicated by a symbol L5 indicates the central axis of the exhaust gas discharge pipe 5. The point indicated by reference sign P5 is a point on the central axis L5 of the exhaust gas discharge pipe 5 and indicates the center of the inlet of the exhaust gas discharge pipe 5.

  As shown in FIG. 6, the center of the exhaust gas discharge port 71 is biased toward the three-way catalyst 2 side from the projection line PRL31 corresponding to the central axis L3 of the GPF3. Correspondingly, the center P5 of the inlet of the exhaust gas discharge pipe 5 is also deviated from the projection line PRL31 corresponding to the central axis L3 of the GPF 3 to the three-way catalyst 2 side.

  According to this configuration, as shown by the solid line arrow in FIG. 6, the exhaust gas flowing into the GPF 3 flows toward the exhaust gas discharge pipe 5. The exhaust gas flow toward the exhaust gas discharge pipe 5 increases the amount of exhaust gas flowing into the shadowed portion of the overlapping portion 31. Therefore, the utilization efficiency of GPF3 can be improved.

  The deviation amount of the center P5 of the exhaust gas discharge pipe 5 is preferably on the VV cross section from the viewpoint of ensuring a sufficient amount of exhaust gas flowing into the overlapping portion 31 and improving the utilization efficiency of the GPF 3. The right side surface 5A on the three-way catalyst 2 side of the exhaust gas discharge pipe 5 can be set to the right side of the GPF side surface 3C on the three-way catalyst 2 side of the GPF 3, that is, on the three-way catalyst 2 side. At this time, from the viewpoint of suppressing an increase in ventilation resistance in the vicinity of the exhaust gas discharge pipe 5, the left side surface 5B of the exhaust gas discharge pipe 5 is more than the side surface 3C of the GPF 3 on the three-way catalyst 2 side on the VV cross section. It is preferable to set the amount of deviation of the exhaust gas discharge pipe 5 so as to be located on the left side.

<EGR device>
The exhaust device 1 includes an EGR device W that recirculates a part of the exhaust gas to the intake system of the engine for the purpose of preventing knocking and reducing the amount of nitrogen oxides NOx.

  As shown in FIGS. 1, 3, and 4, the EGR device W includes an EGR gas extraction pipe 6 (EGR path), a first EGR pipe 62 (EGR path) connected to the EGR gas extraction pipe 6, and a first EGR An EGR cooler 63 (EGR path) connected to the pipe 62 and a second EGR pipe 64 (EGR path) connected to the EGR cooler 63, and the second EGR pipe 64 is connected to a passage of an intake system of the engine, An EGR valve 65 that adjusts the ring flow rate of the EGR gas is provided at the connection portion.

  As shown in FIG. 6, the center of the EGR gas outlet 70 is biased to the opposite side of the exhaust gas outlet 71 from the projection line PRL31 corresponding to the central axis L3 of the GPF 3. The EGR gas extraction pipe 6 is connected to the EGR gas introduction port 72 at the tip of the EGR gas introduction part 72A protruding to the side of the GPF 3 (the side opposite to the side where the exhaust gas discharge pipe 5 is provided). . The EGR gas take-out pipe 6 extends from the EGR gas inlet 72 toward the engine main body side in parallel with the central axis of the GPF 3, and is bent to the side so as to be away from the GPF 3. Followed by

  As a result, as indicated by solid arrows in FIG. 6, the EGR gas can be taken out in the inertia direction of the exhaust gas when the exhaust gas discharged from the three-way catalyst 2 passes through the L-shaped exhaust pipe 4. Therefore, a sufficient amount of EGR gas can be secured. Further, the EGR gas can be taken out while suppressing mutual interference with the exhaust gas flow to the exhaust gas discharge pipe 5. Furthermore, the flow of exhaust gas in the GPF 3 can be distributed to the left and right to be uniform, and the utilization efficiency, function, and performance of the GPF 3 can be further improved.

  Between the exhaust gas outlet 71 and the EGR gas outlet 70 in the downstream cover 7 of the GPF 3, a pedestal 77 having a downstream side exhaust gas outlet 77 </ b> A opened is provided. A downstream exhaust gas extraction part 82 of the apparatus 8 is installed. In the vicinity of the pedestal 77, the flow of the exhaust gas is branched into the exhaust gas discharge port 71 side and the EGR gas extraction port 70 side, and the flow rate of the exhaust gas tends to be gentle and uniform. Therefore, the exhaust gas pressure can be detected without being greatly affected by the pressure change of the exhaust gas by the exhaust gas extraction from the downstream side exhaust gas extraction part 82.

  As shown in FIG. 7, a space 78 having a bottom lower than the EGR gas outlet 70 is formed between the EGR gas outlet 70 and the exhaust gas outlet 71 and below the pedestal 77. ing. Even if the condensed water generated in the EGR gas extraction pipe 6 flows backward, it accumulates in the space portion 78, so that the EGR gas outlet 70 and the EGR gas introduction portion 72A can be prevented from being blocked by the condensed water.

  As shown in FIGS. 2 and 4, the EGR gas take-out pipe 6 and the GPF 3 case are coupled by a first support member 38. Thus, the EGR gas take-out pipe 6 has a portion between the EGR gas take-out port 70 and the portion where the first support member 38 is coupled by the second support member 61, for example, a transmission, a power split device, etc. that are not shown in the figure. Supported by engine related parts. Therefore, the GPF 3 is supported by the engine-related component via the first support member 38, the EGR gas extraction pipe 6 and the second support member 61.

  Further, the EGR device W and the EGR gas introduction portion 72A are arranged on the outer peripheral side bent portion 4C31 side of the L-shaped exhaust pipe 4 (the outer peripheral side of the L-shaped bend in the L-shaped exhaust pipe 4). Since the exhaust gas discharge pipe 5 having a larger exhaust gas flow rate is connected to the GPF 3 on the inner peripheral side bent portion 4C32 side (the inner peripheral side of the L-shaped curve) of the L-shaped exhaust pipe 4, an overlapping portion in the GPF 3 It becomes possible to efficiently flow exhaust gas to the shaded portion 31 and the use efficiency of the GPF 3 is increased.

  In addition, as shown in FIG. 7, the EGR gas introduction part 72 </ b> A is disposed below the center position O <b> 7 of the downstream cover 7 of the GPF 3. The EGR path formed by the EGR gas take-out pipe 6, the first EGR pipe 62, the EGR cooler 63, and the second EGR pipe 64 is connected to the engine intake system from the base end side connected to the EGR introduction port 72. It extends upward to the tip side. By comprising in this way, it can suppress that the condensed water which generate | occur | produced in the EGR path | route accumulates in a path | route.

  Further, as described above, the GPF 3 can simplify the EGR path because the center O3 of the GPF 3 is deviated from the center position of the engine body E in the cylinder row direction to one side (left side) in the cylinder row direction. it can.

<Differential pressure detector>
The differential pressure detection device 8 shown in FIG. 2 detects the differential pressure of the exhaust gas upstream and downstream of the filter body 33 of the GPF 3, and the amount of PM accumulated in the filter body 33 is calculated from the differential pressure. Is done.

  The differential pressure detection device 8 includes an upstream exhaust gas extraction part 81 that extracts exhaust gas upstream of the filter body 33, a downstream exhaust gas extraction part 82 that extracts exhaust gas downstream of the filter body 33, A differential pressure sensor (differential pressure detection unit) 83 that detects the differential pressure from the pressure of the exhaust gas extracted from the extraction units 81 and 82 is provided.

  The upstream exhaust gas extraction portion 81 is provided on the base 47 of the L-shaped exhaust pipe 4 as described above. On the other hand, the downstream exhaust gas extraction part 82 is provided on the base 77 of the downstream cover 7 of the GPF 3 as described above. The upstream side exhaust gas extraction part 81 and the differential pressure sensor 83 are connected by an upstream side exhaust gas extraction pipe 81A shown in FIGS. The downstream side exhaust gas extraction part 82 and the differential pressure sensor 83 are connected by a downstream side exhaust gas extraction pipe 82A.

  As shown in FIG. 2, the upstream side exhaust gas extraction pipe 81A includes an extraction pipe 81A1 and an extraction pipe 81A2 connected to the extraction pipe 81A1. The downstream side exhaust gas extraction pipe 82A includes an extraction pipe 82A1 and an extraction pipe 82A2 connected to the extraction pipe 82A1.

  As shown in FIG. 3, a first support member 85 is fixed to the L-shaped exhaust pipe 4, and a second support member 84 shown in FIG. 4 is fixed to the first support member 85, and this second support member A differential pressure sensor 83 is supported by 84 via a differential pressure sensor mounting plate 83A. As shown in FIG. 2, the second support member 84 is fixed to the cylinder block E1. Since the second support member 84 is coupled to the cylinder block E1 and the L-shaped exhaust pipe 4, the second support member 84 is also used to support the differential pressure sensor 83 and the L-shaped exhaust pipe 4 by the cylinder block E1.

  As shown in FIG. 4, the differential pressure sensor 83 and the upstream side exhaust gas extraction portion 81 are disposed on one side of the GPF 3 (the same left side as the EGR gas extraction pipe 6 is disposed). Therefore, the upstream side exhaust gas extraction pipe 81 </ b> A can also be arranged on one side of the GPF 3, similarly to the EGR gas extraction pipe 6. Further, an extraction pipe support member 81A3 for supporting the upstream side exhaust gas extraction pipe 81A is fixed to the first support member 38 for supporting the GPF 3 and the EGR gas extraction pipe 6. Therefore, the upstream side exhaust gas extraction pipe 81 </ b> A is also supported by the second support member 61 for supporting the GPF 3 and the EGR gas extraction pipe 6. Thus, by using the second support member 61 to support the upstream side exhaust gas extraction pipe 81A, the compactness and layout of the apparatus can be improved.

(Other embodiments)
Hereinafter, other embodiments according to the present invention will be described in detail. In the description of these embodiments, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Although the exhaust device 1 of the first embodiment is applied to an FF vehicle, the independent exhaust pipes of the exhaust manifold M connected to the four exhaust ports are assembled while extending rearward, and the center in the vehicle width direction at the rear of the engine body E It can also be applied to an FR vehicle by extending the side rearward.

  In the first embodiment, the upstream side exhaust purification device is the three-way catalyst 2 and the downstream side exhaust purification device is the GPF 3, but the exhaust purification device is not limited to such a configuration, and various purification devices may be adopted. it can. For example, when the exhaust device 1 is applied to a diesel engine, a diesel particulate filter may be employed instead of the GPF. Further, an oxidation catalyst may be employed as the upstream side exhaust purification device, and a NOx purification catalyst may be employed as the downstream side exhaust purification device, or vice versa.

  In the first embodiment, the downstream end outlet of the exhaust manifold M is disposed on the first cylinder side in the cylinder row direction of the engine, and the upstream opening 4A of the L-shaped exhaust pipe 4 faces the first cylinder side in the cylinder row direction. However, depending on the vehicle layout, the upstream side opening 4A may face another direction, for example, the fourth cylinder side, the upper side, or the lower side.

  The present invention relates to an exhaust system for an engine equipped with an EGR device, and suppresses the interference with the flow of exhaust gas discharged from the exhaust purification device to the exhaust gas discharge port, while supplying EGR gas from the downstream side of the exhaust purification device. Since it can be reliably removed, it is extremely useful.

1 Engine exhaust system 2 Three-way catalyst (upstream exhaust purification system)
2A End face 2B on the upstream side of the three-way catalyst (upstream side exhaust purification device) 2B End face 3GPF (downstream side exhaust purification device) on the downstream side of the three way catalyst (upstream side exhaust purification device)
End face 3B upstream of 3A GPF (downstream exhaust purification apparatus) End face 3C downstream of GPF (downstream exhaust purification apparatus) Side face 4 of GPF (downstream exhaust purification apparatus) L-shaped exhaust pipe 4A Upstream opening 4B Downstream side opening 4C Bent part 4C31 Outer peripheral side bent part 4C32 Inner peripheral side bent part 6 EGR gas extraction pipe (EGR pipe, EGR path)
7 GPF downstream cover (GPF downstream end)
8 Differential pressure detection device 31 Duplicate portion 33 Filter body (purification device body)
35 Case (GPF case)
38 First support member 61 Second support member 70 EGR gas outlet 71 Exhaust gas outlet 78 Space E Engine body E1 Cylinder block E2 Cylinder head L2 Central axis of the three-way catalyst (central axis of the upstream exhaust purification device)
L3 GPF center axis (center axis of downstream exhaust purification system)
M Exhaust manifold W EGR device

Claims (7)

An exhaust purification device that is disposed on the exhaust path of the engine and in which a purification device body that purifies exhaust gas exhausted from the engine is housed in a case;
An EGR device that is connected to the exhaust gas flow direction downstream side of the exhaust gas purification device and circulates a part of the exhaust gas that has passed through the purification device main body as EGR gas to the intake system of the engine,
The downstream end of the case is provided with an exhaust gas discharge port at a position deviated from the central axis of the purification device main body, and is biased to the opposite side of the exhaust gas discharge port from the central axis of the purification device main body. EGR gas outlet is provided at the position
The exhaust system for an engine, wherein the EGR device is disposed on the same side as the EGR gas outlet with respect to a central axis of the purification device main body. In claim 1,
A downstream portion of an L-shaped exhaust pipe bent in an L shape is connected to the upstream side of the exhaust gas flow direction of the exhaust purification device,
The exhaust system for an engine according to claim 1, wherein the EGR gas outlet is biased from the central axis of the purifier main body toward the outer peripheral side of an L-shaped bend in the L-shaped exhaust pipe. In claim 2,
An upstream side exhaust purification device connected to the upstream part of the L-shaped exhaust pipe,
An exhaust system for an engine, wherein when viewed in the axial direction of the exhaust purification device, a downstream portion of the upstream exhaust purification device overlaps a part of an upstream end surface of the exhaust purification device. In claim 3,
The exhaust purification device is disposed in an engine room of an automobile,
The EGR gas outlet is disposed below the center of the downstream end of the case of the exhaust purification device,
An EGR path of the EGR device extends upward from a base end side connected to the EGR gas outlet to a front end side connected to an intake system of the engine. . In claim 4,
An exhaust system for an engine, wherein a space portion having a bottom portion lower than an EGR gas outlet is formed downstream of the purification device main body in the case of the exhaust purification device. In claim 4 or claim 5,
A first support member that couples the case of the exhaust emission control device and an EGR pipe constituting the EGR path;
An exhaust system for an engine, comprising: a second support member that supports a portion of the EGR pipe between the EGR gas outlet and a portion where the first support member is coupled. In any one of Claims 2 thru | or 6,
The engine is an in-line multi-cylinder engine;
The exhaust purification device is provided so that a central axis of the purification device main body is substantially perpendicular to a cylinder row direction of the engine, and the EGR device is disposed from a center position of the engine in the cylinder row direction of the engine. An exhaust system for an engine, wherein the exhaust system is biased toward the arrangement side.

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