ENGINE EGR INSTALLATION STRUCTURE

Abstract

Engine EGR installation structure, comprehensive: an exhaust pipe (10) which is attached to a front of a cylinder head (2); an inlet manifold (15) which is attached to the rear of the cylinder head (2); and an EGR device (20) that returns exhaust gas from the exhaust pipe (10) to the intake manifold (15), wherein the EGR device (20) includes an EGR pipe (21, 22) which passes along one side of an end wall (31) forming an end region of the cylinder head (2) in a cylinder row direction in order to create a connection between the exhaust pipe (10) and the intake manifold (15), includes an EGR cooler (23) which is located in the middle of the EGR pipe (21, 22), and includes an EGR valve (24) which is connected to a downstream side of the EGR cooler (23), characterized in that a cooler outlet-side flange (23C), to which the EGR valve (24) is attached from above, is present at a downstream end of the EGR cooler (23), the EGR cooler (23) is arranged on the side of the end wall (31) in an inclined position such that the downstream end is located above and behind an upstream end of the EGR cooler (23), the EGR valve (24) includes a valve inlet flange (24A) connected to the cooler outlet flange (23C), a cylinder housing (24B) extending upwards from the valve inlet flange (24A), and a valve outlet flange (24C) provided in a zone above the valve inlet flange (24A) in the housing (24B), and the engine EGR installation structure features: a lower support (40) connected to a lower part of the EGR cooler (23) and a lower part of the end wall (31) to support the EGR cooler (23); and an upper support (50) connected to the zone above the valve inlet side flange (24A) in the housing (24B) and an upper part of the end wall (31) to support the EGR valve (24), wherein the valve outlet side flange (24C) opens in the direction of the side of the intake manifold (15) which crosses the cylinder row direction, the EGR pipe (21, 22) includes an exhaust-side EGR pipe (22) that communicates between the valve outlet-side flange (24C) and the intake manifold (15), and the upper support (50) is arranged on the opposite side of the valve outlet flange (24C) with respect to the housing (24B) and is attached to the housing (24B) by using a fastening element (17) which serves to attach the outlet-side EGR pipe (22) to the valve outlet flange (24C).

Description

Technical area

[0001] The present invention relates to an engine EGR installation structure. Technical background

[0002] A conventional EGR device installation structure for an engine is known from JP 2016 - 143 45 A. In this engine EGR installation structure, the EGR device is located on the engine side, where a catalyst is attached. The EGR device includes an EGR passage, an EGR cooler, and an EGR valve provided in the EGR passage. The EGR device cools exhaust gas using the EGR cooler and guides the exhaust gas from an exhaust path to an intake path via the EGR passage, while adjusting the exhaust gas flow rate using the EGR valve.

[0003] From JP 2019 - 157 800 A an engine EGR installation structure with central features of the preamble of claim 1 is known.

[0004] Furthermore, from DE 10 2019 110 558 A1 an EGR installation structure of an internal combustion engine is known, in which the zone above a valve inlet side flange in a housing and an upper part of an end wall are connected in order to support the EGR valve. Disclosure of the inventionTechnical problem

[0005] The EGR gas recirculation rate must be increased to comply with emissions regulations.

[0006] To increase the EGR gas recirculation flow rate, the cooling performance of the EGR cooler must also be improved, with the size of the EGR cooler increasing accordingly. Increasing the size of the EGR cooler requires providing space for the EGR cooler in the engine compartment. When installing the larger EGR cooler in the engine, vibration suppression measures for the EGR valve, a heavy component sensitive to engine vibration, must also be considered.

[0007] However, in the engine described in JP2016-14345A, there is still room for vibration suppression measures for the EGR valve if the EGR valve is arranged at a location remote from the engine block in order to increase the size of the EGR cooler.

[0008] The present invention has been implemented in view of the above circumstances, and it is an object of the present invention to provide an EGR installation structure that allows an increase in the size of the EGR cooler and can suppress vibrations of the EGR valve. Solution to the problem

[0009] The present invention provides an engine EGR mounting structure including the features of claim 1. Advantageous effects of the invention

[0010] By the invention explained above, it is possible to increase the size of the EGR cooler and suppress vibrations of the EGR valve. Short description of the drawings Fig. 1 is a left side view of an engine having an EGR device installation structure according to an embodiment of the invention. Fig. 2 is a left side view of an upper part of the engine with the EGR device installation structure according to the embodiment of the invention. Fig. 3 is a cross-sectional view when viewed in the direction of travel III-III of the Fig. 1 shown engine. Fig. 4 is a plan view of the engine having the EGR installation structure according to the embodiment of the invention. Fig. 5 is a plan view of a cylinder head of the engine having the EGR installation structure according to the embodiment of the invention. Fig. 6 is a rear view of an upper part of the engine with the EGR installation structure according to the embodiment of the invention. Fig. 7 is a rear view of a cylinder head of the engine having the EGR installation structure according to the embodiment of the invention. Fig. 8 is a perspective view of an engine upper bracket having the EGR installation structure according to the embodiment of the invention. Fig. 9 is a front view of an engine upper bracket having the EGR installation structure according to the embodiment of the invention. Fig. 10 is a left side surface of the upper bracket of the engine with the EGR installation structure according to the embodiment of the invention. Fig. 11 is a rear view of the engine upper bracket with the EGR installation structure according to the embodiment of the invention. Description of the embodiment

[0011] An EGR installation structure according to an embodiment of the invention includes: an exhaust pipe attached to a front of a cylinder head; an intake manifold attached to the rear of the cylinder head; and an EGR device that recirculates exhaust gas from the exhaust pipe to the intake manifold. The EGR device includes an EGR pipe that passes along one side of an end wall forming an end portion of the cylinder head in a cylinder row direction to establish communication between the exhaust pipe and the intake manifold, an EGR cooler located in the center of the EGR pipe, and an EGR valve connected to a downstream side of the EGR cooler. A cooler outlet-side flange, to which the EGR valve is attached from above, is provided at a downstream end of the EGR cooler. The EGR cooler is arranged on the end wall side in an inclined position such thatThe downstream end is located above and behind an upstream end of the EGR cooler. The EGR valve includes a valve inlet-side flange connected to the cooler outlet-side flange. A cylinder housing extends upward from the valve inlet-side flange and includes a valve outlet-side flange provided in a zone above the valve inlet-side flange in the housing. The engine EGR mounting structure includes: a lower support connected to a lower part of the EGR cooler and a lower part of the end wall to support the EGR cooler; and an upper support connected to the zone above the valve inlet-side flange in the housing and an upper part of the end wall to support the EGR valve. Thus, the engine EGR mounting structure according to the embodiment of the invention can increase the size of the EGR cooler and suppress vibrations of the EGR valve. Embodiment

[0012] Hereinafter, an engine EGR device installation structure (hereinafter simply referred to as EGR installation structure) according to an embodiment of the invention will be described with reference to the accompanying drawings. Fig. 1 to 11 are diagrams illustrating the EGR installation structure according to the embodiment of the invention. Fig. 1 to 11, the up-down, front-back, and left-right directions refer to the up-down, front-back, and left-right directions of an engine installed in the vehicle, and a direction orthogonal to the front-back direction (hereinafter also referred to as the longitudinal direction) is a left-right direction (hereinafter also referred to as the width direction), and a height direction of the engine is a up-down direction.

[0013] First, a structure will be described. As in Fig. 1, an engine 1 includes an engine block 1A.

[0014] The engine block 1A includes a cylinder block 3, a cylinder head 2 connected to the upper part of the cylinder block, a head cover 4 on the upper part of the cylinder head 2, and an oil pan 5 connected to a lower part of the cylinder block 3. The engine block 1A also includes a chain cover 8 (see Fig. 7), which is located at the right end areas of the cylinder head 2 and the cylinder block 3.

[0015] A plurality of (three) cylinders (not shown), each of which accommodates a piston (not shown) in a reciprocating manner, are formed in the cylinder block 3. The cylinder block 3 accommodates a crankshaft 11 that converts the reciprocating motion of the piston into a rotary motion, with the crankshaft 11 extending in the width direction. The plurality of cylinders are arranged side by side in the width direction, that is, in the direction in which the crankshaft 11 extends (hereinafter also referred to as the "cylinder bank direction").

[0016] A plurality of combustion chambers (not shown) are located in the base portion of the cylinder head 2. The combustion chamber is provided at the top of each cylinder. In the present embodiment, three combustion chambers are provided in a row in the width direction on the cylinder head 2.

[0017] An exhaust outlet (not shown in the drawings) is located in front of the cylinder head 2, and a catalyst housing 10 is provided at the exhaust outlet in the form of an exhaust pipe.

[0018] As in Fig. As shown in Figure 7, three intake ports 38 corresponding to the three cylinders are provided at the rear of the cylinder head 2. The engine 1 causes a spark plug (not shown) to ignite and combust an air-fuel mixture of air and fuel taken in through the intake port 38, after which an exhaust gas is discharged through an exhaust outlet after combustion.

[0019] As in Fig. As shown in Figure 1, the engine 1 has an intake manifold 15 attached to the rear of the cylinder head 2. The engine 1 is equipped with an EGR device 20 that recirculates exhaust gas from the catalyst housing 10 into the intake manifold 15.

[0020] The EGR device 20 includes an inlet-side EGR pipe 21 and an outlet-side EGR pipe 22 as EGR pipes, an EGR cooler 23 between the inlet-side EGR pipe 21 and the outlet-side EGR pipe 22, and an EGR valve 24 connected to a downstream side of the EGR cooler 23.

[0021] As in Fig. 2 and Fig. As shown in Figure 5, the cylinder head 2 includes a front end wall 31, which forms one end portion (the left end portion of this embodiment) of the cylinder head 2 in the cylinder bank direction. The intake-side EGR pipe 21 and the exhaust-side EGR pipe 22 communicate between the catalyst housing 10 on the front side of the cylinder head 2 and the intake manifold 15 on the rear side of the cylinder head 2 through the side of the one front end wall 31 of the cylinder head 2.

[0022] As in Fig. 1 and Fig. 2, the EGR cooler 23 includes a heat sink 23B that cools the exhaust gas, a cooler inlet-side flange 23A at the bottom end of the heat sink 23B, and a cooler outlet-side flange 23C at the top end of the heat sink 23B.

[0023] The heat sink 23B of the EGR cooler 23 cools the exhaust gas by heat exchange with cooling water.

[0024] The cooling water circulates in the cooling body 23B to / from the engine block 1A. Here, an upper end portion of the EGR cooler 23 is located at its downstream end in the exhaust gas flow direction. On the other hand, a lower end portion of the EGR cooler 23 is an upstream end of the EGR cooler 23 in the exhaust gas flow direction. The EGR valve 24 is attached to the cooler outlet-side flange 23C from above.

[0025] At an upstream end of the inlet-side EGR pipe 21, there is a flange 21A connected to the catalyst housing 10. At a downstream end of the inlet-side EGR pipe 21, there is a flange 21C connected to the cooler inlet-side flange 23A of the EGR cooler 23. At an upstream end of the outlet-side EGR pipe 22, there is a flange 22A. At a downstream end of the outlet-side EGR pipe 22, there is a flange 22C.

[0026] The EGR cooler 23 is located on the side of one front end wall 31 in an inclined position with the downstream end (the upper end portion) above and behind the upstream end (the lower end portion).

[0027] The EGR valve 24 includes a valve inlet side flange 24A connected to the cooler outlet side flange 24C, a cylindrical housing 24B extending upward from the valve inlet side flange 24A, and a valve outlet side flange 24C.

[0028] The valve outlet-side flange 24C is located in a zone of the housing 24B above the valve inlet-side flange 24A. The housing 24B accommodates a valve body (not shown) and corresponds to a body of the EGR valve 24.

[0029] The engine 1 is equipped with a lower support 40 that supports the EGR cooler 23. The lower support 40 is connected to a lower part of the EGR cooler 23 and a lower part of one front end wall 31. In other words, the EGR cooler 23 is supported by the lower part of one front end wall 31 of the cylinder head 2 via the lower support 40.

[0030] The engine 1 is equipped with an upper support 50 that supports the EGR valve 24. The upper support 50 is connected to a region of the housing 24B of the EGR valve 24 above the valve inlet-side flange 24A and an upper part of one end wall 31. In other words, the EGR valve is supported by the upper part of one end wall 31 of the cylinder head 2 via the upper support 50.

[0031] A cooling water outlet 18 is located in one end wall 31 of the cylinder head 2, and a radiator (not shown) is connected to the cooling water outlet 18 via a cooling water pipe (not shown). The cooling water that has cooled the interior of the cylinder head 2 is discharged from the cooling water outlet 18, cooled by the radiator, and then returned to the engine 1.

[0032] To avoid collision with the cooling water outlet 18, the EGR cooler 23 is located along a zone behind and below the cooling water outlet 18 on one front end wall 31 of the cylinder head 2. Installation locations and installation positions of the EGR cooler 23 and the EGR valve 24 are also limited by the installation location of the cooling water outlet 18 in the engine 1 of this embodiment equipped with the EGR device 20.

[0033] As in Fig. 3, the radiator outlet-side flange 23C includes maximum protrusions 23D, each of which is a zone where the amount of radial outward protrusion from the intake-side EGR pipe 21 is maximum. The radiator outlet-side flange 23C in this embodiment includes a pair of maximum protrusions 23D projecting in opposite directions to each other.

[0034] The maximum protrusions 23D protrude from the intake-side EGR pipe 21 in a direction transverse to the cylinder row direction, that is, in the longitudinal direction. Note that the valve inlet-side flange 24A, which is connected to the radiator outlet-side flange 23C, is configured in the same shape as the radiator outlet-side flange 23C and includes a zone corresponding to the maximum protrusion 23D.

[0035] As in Fig. As shown in FIG. 4, the valve exhaust-side flange 24C opens toward the intake manifold 15 side (toward the rear) in the direction crossing the cylinder row direction. The exhaust-side EGR pipe 22 connects the valve exhaust-side flange 24C and the intake manifold 15 to guide the exhaust gas from the valve exhaust-side flange 24C to the intake manifold 15.

[0036] As in the Fig. 4 and Fig. 6, the intake manifold 15 includes a surge tank 15A which temporarily stores air, and three intake manifold parts 15B which branch off from the surge tank 15A and are connected to the inlet opening 38 (see Fig. 7).

[0037] The intake manifold 15 includes a branch pipe 15C connecting the exhaust-side EGR pipe 22 to the three manifold parts 15B to distribute the exhaust gas taken from the exhaust-side EGR pipe 22 to the manifold parts 15B.

[0038] As in Fig. As shown in Figure 1, the flange 22A of the exhaust-side EGR pipe 22 is fastened to the valve outlet-side flange 24C of the EGR valve 24 by means of fasteners 17. The fastener 17 here is a bolt. The flange 22 is attached to the valve outlet-side flange 24C with two fasteners 17.

[0039] The upper support 50 is located on the opposite side of the valve outlet side flange 24C with respect to the housing 24B. Specifically, the valve outlet side flange 24C is located behind the housing 24B, and the upper support 50 is located in front of the housing 24B.

[0040] The upper bracket 50 is fixed to the housing 24B with the fasteners 17. In other words, the upper bracket 50 is fixed to the housing 24B by sharing the fastener 17, which serves to connect the exhaust-side EGR pipe 22 to the valve outlet-side flange 24C. In other words, the upper bracket 50 is attached to the housing 24B by "co-fixing" the common fastener 17.

[0041] As in the Fig. 8, Fig. 9, Fig. 10 and Fig. As shown in Fig. 11, the upper bracket 50 includes a plate-shaped base portion 54 extending along one end wall 31 in the height direction, and a projection 55 projecting from the base portion 54 in the cylinder row direction. The direction along the one end wall 31 is a direction (longitudinal direction) orthogonal to the cylinder row direction (width direction).

[0042] Therefore, the base part 54 spreads along a plane parallel to the one front end wall 31, and the projection 55 projects in a direction orthogonal to this base part 54. For this reason, when viewed from above, the upper support 50 has a T-shape.

[0043] The base part 54 includes a first fixing part 51 fixed to a rear end and to the upper part of the one front end wall 31, a second fixing part 52 fixed to the rear end of the one front end wall 31 and below the first fixing part 51, and a third fixing part 53 fixed to the upper end of the one front end wall 31 and in front of the first fixing part 51.

[0044] The first fixing part 51, the second fixing part 52 and the third fixing part 53 have a cylindrical shape (a hub shape) with a hole through which a fastening element 16 (see Fig. 2) is inserted, and with a higher rigidity than the remaining portions of the base part 54. In this way, the upper support 50 is firmly attached to the one front end wall 31 of the cylinder head 3 at three locations of the first fixing part 51, the second fixing part 52 and the third fixing part 53 of the plate-shaped base part 54.

[0045] The projection 55 includes a rib 56 projecting in the cylinder row direction and an EGR valve support 57 projecting further in the cylinder row direction from the upper end portion of the rib 56. The rib 56 projects in the cylinder row direction from the zone surrounded by the first fixing portion 51, the second fixing portion 53, and the third fixing portion 53 of the base portion 54.

[0046] The rib extends straight in the height direction. The housing 24B is attached to the EGR valve support 57. The boss-shaped part 57A is formed in the protrusion direction near the distal end portion of the EGR valve support 57, and the boss-shaped part 57B is formed in the protrusion direction at a proximal end portion (the area near the base portion 54) of the EGR valve support 57.

[0047] The hub-shaped parts 57A and 57B have a cylindrical shape (hub shape) with a hole through which the fastening element 17 is inserted, and which has a higher strength than the other parts of the EGR valve support 57. The hub-shaped part 57A is formed near the distal end portion of the EGR valve support 57 in the protrusion direction, and the hub-shaped part 57B is formed at the proximal end portion (zone near the base part 54) of the EGR valve support 57 in the protrusion direction.

[0048] As in Fig. 3 and Fig. As shown in Figure 5, one end wall 31 forms one end portion (the left end portion) of the cylinder head 2 in the cylinder bank direction. The cylinder head 2 includes another end wall 32, which forms another end portion (the right end portion) of the cylinder head 2 in the cylinder bank direction.

[0049] The cylinder head 2 includes a boss portion 35 extending from the other end wall 32 in the cylinder row direction and communicating with the one end wall 31. An oil path 35A is formed within the boss portion 35.

[0050] In the present embodiment, the cylinder head 2 is provided with two boss portions 35 that run parallel to each other. A connecting portion 36 is provided on one end wall 31 of the cylinder head 2. An internal thread, with which the fastening element 16 (see Fig.2), into which the third fixing part 53 is inserted, is formed in the connecting part 36.

[0051] The fastening part 36 connects the third fixing part 53 and the hub part 35. The fastening part 36 not only functions as a hub that receives the fastening element 16, but also has the function of absorbing a load from the fastening element 16, which fixes the third fixing part 53 to the hub part 35.

[0052] As explained above, in this embodiment, the cooler outlet-side flange 23C, to which the EGR valve 24 is attached from above, is provided at the downstream end of the EGR cooler 23. This is located on the side of one front end wall 31 in an inclined position, with the downstream end located above and behind the upstream end.

[0053] The EGR valve 24 includes the valve inlet side flange 24A connected to the cooler outlet side flange 24C, the cylindrical housing 24B extending upward from the valve inlet side flange 24A, and the valve outlet side flange 24C located in the zone above the valve inlet side flange 24A in the housing 24B.

[0054] The engine 1 is provided with the lower bracket 40 connected to the lower part of the EGR cooler 23 and the lower part of the one end wall 31 to support the EGR cooler 23, and is provided with the upper bracket 50 connected to the zone above the valve inlet side flange 24A in the housing 24B and the upper part of the one end wall 31 to support the EGR valve 24.

[0055] Thus, since the EGR cooler 23 is located on the one front end wall 31 side of the cylinder head 2 in an inclined position with the downstream end above and behind the upstream end, it is possible to increase the length of the EGR cooler 23, compared with the case that the EGR cooler 23 is in an upright position so that it extends in the height direction or is in a tilted position so that the EGR cooler 23 extends in the longitudinal direction.

[0056] Now, when the cooler outlet side flange 23C extends in the longitudinal direction or the EGR valve 24 is in a tilted position, the space available for mounting the EGR cooler 23 may be limited by the cooler outlet side flange 23C and the EGR valve 24, and it is not possible to expand the size of the EGR cooler 23 in the height direction.

[0057] Thus, in the present embodiment, the cooler outlet-side flange 23C is provided at the downstream end of the EGR cooler 23, and the cooler outlet-side flange 23C opens upward. The valve inlet-side flange 24A of the EGR valve 24 is connected to the cooler outlet-side flange 23C. The housing 24B of the EGR valve 24 is located at a position extending upward from the valve outlet-side flange 24A (upright position).

[0058] This structure makes it possible to expand the size of the EGR cooler 23 in the height direction without limiting the installation space for the EGR cooler 23, and the size of the EGR cooler 23 can be increased.

[0059] The lower part of the EGR cooler 23 is fixed to the lower part of the one end wall 31 by means of the lower bracket 40, and an intermediate portion in the height direction of the housing 24B of the EGR valve 24 is connected to the upper part of the one end wall 31 by the upper bracket 50, whereby it is possible to fix the lower part of the EGR cooler 23 and the upper part of the EGR valve 24 to the one end wall 31 by the lower bracket 40 and the upper bracket 50, respectively, so that vibration of the EGR cooler 23 and the EGR valve 24 is reduced.

[0060] As a result, it is possible to increase the size of the EGR cooler 23 and suppress vibrations of the EGR valve 24.

[0061] In this embodiment, the cooler outlet-side flange 23C includes the maximum protrusion 23D where the amount of protrusion from the intake-side EGR pipe 31 in the radially outward direction is maximum. Therefore, if the cooler outlet-side flange 23C is disposed with the maximum protrusion 23D located at a position where it protrudes in the cylinder bank direction, the EGR valve 24 and the EGR cooler 23 must be disposed apart from the cylinder head 2 in the cylinder bank direction to prevent the maximum protrusion 23D from coming into contact with the cylinder head 2. In this case, the upper bracket 50 supports the EGR valve 24 at a position apart from the cylinder head 2, and the arm length of the upper bracket 50 increases, so that the effect of suppressing the vibration of the EGR valve 24 and the EGR cooler 23 is reduced.Therefore, in this embodiment, the maximum projection 23D protrudes from the intake-side EGR pipe 21 in a direction crossing the cylinder row direction.

[0062] Therefore, by providing the maximum protrusion 23D to protrude in the direction transverse to the cylinder bank direction, it is possible to bring the EGR valve 24 and the EGR cooler 23 closer to the cylinder head 2 and thereby suppress vibrations of the EGR valve 24 and the EGR cooler 23.

[0063] In the present embodiment, the valve outlet side flange 24C opens toward the intake manifold 15 side in the direction crossing the cylinder row direction.

[0064] The EGR pipe includes the exhaust-side EGR pipe 22, which creates a connection between the valve outlet-side flange 24C and the intake manifold 15.

[0065] The upper bracket 50 is located on the side opposite the valve outlet-side flange 24C with respect to the housing 24B. The upper bracket 50 is fixed to the housing 24B by using the fixing member 17, which serves to connect the outlet-side EGR pipe 22 to the valve outlet-side flange 24C.

[0066] Thus, the common fixing member 17 enables the exhaust-side EGR pipe 22 and the upper bracket 50 to be fixed on the intake manifold 15 side of the housing 24B and the opposite side by so-called “common fixing,” which in turn makes it possible to increase the rigidity in supporting the EGR valve 24 and suppress vibrations of the EGR valve 24.

[0067] In the present embodiment, the upper bracket 50 includes the plate-shaped base part 54 extending along the one end wall 31 in the height direction, and the protrusion 55 protruding from the base part 54 in the cylinder row direction. The base part 54 includes the first fixing part 51 fixed to the rear end and upper part of the one end wall 31, the second fixing part 52 fixed to the rear end of the one end wall 31 and below the first fixing part 51, and the third fixing part 53 fixed to the upper end of the one end wall 31 and in front of the first fixing part 51.

[0068] The projection 55 includes the rib 56 which projects from the region surrounded by the first fixing part 51, the second fixing part 52 and the third fixing part 53 of the base part 51 in the cylinder row direction and extends in the height direction, and the EGR valve support 57 which further projects from the upper end portion of the rib 56 in the cylinder row direction and to which the housing 24B is fixed.

[0069] In this way, the plate-shaped base part 54 of the upper bracket 50 can be securely fixed to the rear end or the upper end of the one front end wall 31, which is a high-strength portion of the cylinder head 2, at the plurality of fixing parts, namely the first fixing part 51, the second fixing part 52, and the third fixing part 53. This enables an increase in the rigidity of the support of the upper bracket 50.

[0070] By causing the EGR valve support 57 to protrude from the upper end portion of the rib 56 of the upper support 50 in the cylinder row direction, the upper support 50 can support the EGR valve 24 at a high position. This makes it possible to dispose the EGR valve 54 at a higher position, increase the height of the EGR cooler 23, and increase the rigidity of the support of the upper support 50 that supports the EGR valve 24.

[0071] In the present embodiment, the one end wall 31 is provided at one end portion (the left end portion) of the cylinder head 2 in the cylinder row direction, and the other end wall 23 is located at the other end portion (the right end portion) in the cylinder row direction. The cylinder head 52 includes the boss portion 35 extending in the cylinder row direction from the other end wall 23, communicating with the one end wall 31, and including the oil path 35A formed therein. The one end wall 31 includes the connecting portion 36 connecting the third fixing portion 53 and the boss portion 35.

[0072] The third fixing part 53 is connected to the hub part 35, the rigidity of which is increased with the oil path 35A formed therein, via the connecting part 36 of the one front end wall 31, and thereby it is possible to increase the rigidity for supporting the upper bracket 50 on the third fixing part 53.

[0073] Although one embodiment of the invention has been disclosed, it will be apparent to those skilled in the art that modifications may be added without departing from the spirit and scope of the invention. All such modifications and equivalents are covered by the claims. List of reference symbols

[0074] 1 ... engine, 2 ... cylinder head, 10 ... catalyst housing (exhaust pipe), 15 ... intake manifold, 17 ... fastener, 20 ... EGR device, 21 ... intake-side EGR pipe (EGR pipe), 22 ... exhaust-side EGR pipe (EGR pipe), 23 ... EGR cooler, 23C ... cooler outlet-side flange, 23D ... maximum projection, 24 ... EGR valve, 24A ... valve inlet-side flange, 24B ... housing, 24C ... valve outlet-side flange, 31 ... one end wall (end wall), 32 ... the other end wall, 35 ... boss part, 35A ... oil path, 36 ... connecting part, 40 ... lower bracket, 50 ... upper bracket, 51 ... first fixing part, 52 ... second fixing part, 53 ... third fixing part, 54 ... base part, 55 ... projection, 56 ... rib, 57 ... EGR valve support

Claims

[1] Engine EGR installation structure, comprising: an exhaust pipe (10) attached to a front of a cylinder head (2); an intake manifold (15) attached to the rear of the cylinder head (2); and an EGR device (20) which returns an exhaust gas from the exhaust pipe (10) to the intake manifold (15), wherein the EGR device (20) includes an EGR pipe (21, 22) passing on one side of an end wall (31) forming an end portion of the cylinder head (2) in a cylinder row direction to provide communication between the exhaust pipe (10) and the intake manifold (15), an EGR cooler (23) located in a center of the EGR pipe (21, 22), and an EGR valve (24) connected to a downstream side of the EGR cooler (23), characterized by , that a cooler outlet-side flange (23C), to which the EGR valve (24) is attached from above, is provided at a downstream end of the EGR cooler (23), the EGR cooler (23) is arranged on the side of the end wall (31) in an inclined position such that the downstream end is located above and behind an upstream end of the EGR cooler (23), the EGR valve (24) includes a valve inlet-side flange (24A) connected to the cooler outlet-side flange (23C), a cylinder housing (24B) extending upward from the valve inlet-side flange (24A), and a valve outlet-side flange (24C) provided in a zone above the valve inlet-side flange (24A) in the housing (24B), and the engine EGR installation structure has: a lower support (40) connected to a lower part of the EGR cooler (23) and a lower part of the end wall (31) to support the EGR cooler (23); and an upper support (50) connected to the zone above the valve inlet side flange (24A) in the housing (24B) and an upper part of the end wall (31) to support the EGR valve (24), wherein the valve outlet side flange (24C) opens towards the side of the intake manifold (15) which crosses the cylinder row direction, the EGR pipe (21, 22) includes an exhaust-side EGR pipe (22) communicating between the valve outlet-side flange (24C) and the intake manifold (15), and the upper support (50) is arranged on an opposite side of the valve outlet-side flange (24C) with respect to the housing (24B) and is fixed to the housing (24B) by sharing a fixing member (17) which serves to fix the outlet-side EGR pipe (22) to the valve outlet-side flange (24C). [2] The engine EGR mounting structure according to claim 1, wherein the cooler outlet side flange (23C) includes a maximum protrusion (23D) where an amount of protrusion from the EGR pipe (21, 22) to an outside in a radial direction is maximum, and the maximum protrusion (23D) protrudes from the EGR pipe (21, 22) in a direction crossing the cylinder row direction. [3] An engine EGR mounting structure according to claim 1 or 2, wherein the upper support (50) includes a plate-shaped base part (54) extending along the end wall (31) in the up-down direction and a projection (55) projecting from the base part (54) in the cylinder row direction, the base part (54) contains: a first fixing part (51) fixed to a rear end and to the upper part of the end wall (31), a second fixing part (52) fixed to the rear end of the end wall (31) and located below the first fixing part (51); and a third fixing part (53) fixed to an upper end of the end wall (31) and in front of the first fixing part (51), and the projection (55) contains: a rib (56) projecting in the cylinder row direction from a zone surrounded by the first fixing part (51), the second fixing part (52) and the third fixing part (53) of the base part (54) and extending in the up-down direction; and an EGR valve support (57) which projects from an upper end portion of the rib (56) in the cylinder row direction and to which the housing (24B) is fixed. [4] An engine EGR mounting structure according to claim 3, wherein the end wall (31) is a front end wall which forms an end region of the cylinder head (2) in the cylinder row direction, the cylinder head (2) contains: a further end wall (32) forming a further end region of the cylinder head (2) in the cylinder row direction; and a projection (35) extending from the other end wall (32) in the cylinder row direction and communicating with the one end wall (31), an oil path (35A) being formed within the projection (35), and one end wall (31) has a connecting part (36) which connects the third fixing part (53) and the extension (35) to one another.

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