EGR device for internal combustion engines

Abstract

To provide an EGR device for an internal combustion engine capable of enhancing support rigidity of an EGR valve relative to a cylinder head cover and preventing deterioration of control accuracy of the EGR valve by preventing vibration of the EGR valve.SOLUTION: An EGR device 11 for an engine 1 includes: upstream side EGR piping 12, an EGR cooler 13, an EGR housing passage part 26 and downstream side EGR piping 15 which are branched from an exhaust emission control device 9 to recirculate part of exhaust gas flowing in the exhaust emission control device 9 to an intake manifold 8 as EGR gas; and an EGR valve 14 for controlling a flow rate of EGR gas flowing in the EGR housing passage part 26. The EGR valve 14 is fastened to a first fastening part 27A provided in an intersection part 29 in which a front wall 25A and a left side wall 25C of an EGR housing part 25 intersect with each other and a second fastening part 27B provided on the front wall 25A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an EGR device for an internal combustion engine. [Background technology]

[0002] BACKGROUND ART Conventionally, engines equipped with an EGR (Exhaust Gas Recirculation) device that recirculates part of exhaust gas to the intake side are known (see Patent Document 1).

[0003] The EGR device of this engine is equipped with an EGR valve that adjusts the flow rate of EGR gas, and the EGR valve is cantilevered on the engine by a fixing bracket. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7000969 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional engines, the EGR valve is supported on the engine in a cantilevered manner by a fixing bracket.

[0006] Because the EGR valve is a heavy component equipped with an actuator for valve operation, simply supporting it on one side of the engine with a metal fixture provides insufficient support rigidity, causing the EGR valve to vibrate due to engine vibrations, which can reduce the control accuracy of the EGR valve.

[0007] The present invention has been made in light of the above-mentioned circumstances, and aims to provide an EGR device for an internal combustion engine that can increase the support rigidity of the EGR valve relative to the cylinder head cover, prevent the EGR valve from vibrating, and prevent a decrease in the control accuracy of the EGR valve. [Means for solving the problem]

[0008] The present invention provides an EGR device for an internal combustion engine that is provided in an internal combustion engine body having a cylinder head cover and has an exhaust passage portion into which exhaust gas discharged from the internal combustion engine body is introduced, the cylinder head cover having an exhaust side wall located on the side of the internal combustion engine body where the exhaust passage portion is installed, an intake side wall located on the opposite side of the exhaust side wall, and a connecting wall that connects the exhaust side wall and the intake side wall, and is characterized in that it comprises an EGR passage portion that branches off from the exhaust passage portion and recirculates a portion of the exhaust gas flowing through the exhaust passage portion to the intake side of the internal combustion engine body as EGR gas, and an EGR valve that adjusts the flow rate of EGR gas flowing through the EGR passage portion, and the EGR valve is fastened to a first fastening portion provided at an intersection where the exhaust side wall and the connecting wall intersect and a second fastening portion provided on the exhaust side wall. [Effects of the Invention]

[0009] As described above, according to the present invention, the supporting rigidity of the EGR valve relative to the cylinder head cover can be increased, and vibration of the EGR valve can be prevented, thereby preventing a decrease in the control accuracy of the EGR valve. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front view of an internal combustion engine equipped with an EGR device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a left side view of an internal combustion engine equipped with an EGR device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a front view of a cylinder head and a cylinder head cover of an internal combustion engine according to one embodiment of the present invention. [Figure 4] FIG. 4 is a left side view of the cylinder head and cylinder head cover of the internal combustion engine according to one embodiment of the present invention. [Figure 5] FIG. 5 is a plan view of an EGR housing portion of an internal combustion engine according to one embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view of the front wall side of the EGR housing part of the internal combustion engine according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] An EGR device for an internal combustion engine according to one embodiment of the present invention is provided in an internal combustion engine body having a cylinder head cover, and has an exhaust passage portion into which exhaust gas discharged from the internal combustion engine body is introduced, the cylinder head cover having an exhaust side wall located on the side of the internal combustion engine body where the exhaust passage portion is installed, an intake side wall located opposite the exhaust side wall, and a connecting wall connecting the exhaust side wall and the intake side wall. The EGR device is provided with an EGR passage portion that branches off from the exhaust passage portion and returns a portion of the exhaust gas flowing through the exhaust passage portion to the intake side of the internal combustion engine as EGR gas, and an EGR valve that adjusts the flow rate of EGR gas flowing through the EGR passage portion, and the EGR valve is fastened to a first fastening portion provided at the intersection where the exhaust side wall and the connecting wall intersect, and a second fastening portion provided on the exhaust side wall.

[0012] As a result, the EGR device for an internal combustion engine according to one embodiment of the present invention can increase the support rigidity of the EGR valve relative to the cylinder head cover, preventing the EGR valve from vibrating and preventing a decrease in the control accuracy of the EGR valve. [Example]

[0013] An EGR device for an internal combustion engine according to an embodiment of the present invention will now be described with reference to the drawings. 1 to 6 are diagrams showing an EGR device for an internal combustion engine according to one embodiment of the present invention. In Fig. 1 to 6, the up, down, front, rear, left and right directions are based on the internal combustion engine installed in a vehicle, and the front and rear direction of the vehicle is defined as the front-rear direction, the left and right direction of the vehicle (vehicle width direction) is defined as the left and right direction, and the up and down direction of the vehicle (vehicle height direction) is defined as the up and down direction.

[0014] First, the configuration will be described. In Fig. 1, an engine 1 is provided in an engine room (not shown) of a vehicle. The engine 1 has an engine body 2, which is made up of a cylinder block 3, a cylinder head 4, a cylinder head cover 5, and an oil pan 6. In this embodiment, the engine 1 constitutes an internal combustion engine, and the engine body 2 constitutes the internal combustion engine body.

[0015] A cylinder head 4 is attached to the top of the cylinder block 3, and a cylinder head cover 5 is attached to the top of the cylinder head 4. An oil pan 6 is attached to the bottom of the cylinder block 3, and oil for lubricating the engine 1 is stored in the oil pan 6.

[0016] The cylinder block 3 is provided with a plurality of cylinders (not shown), which are arranged in the vehicle width direction. Each cylinder houses a piston (not shown), and the pistons are connected to a crankshaft 7 (see FIG. 2) via a connecting rod (not shown).

[0017] The engine 1 of this embodiment is a transversely mounted engine with a crankshaft 7 extending in the vehicle width direction, and the vehicle is a FF (front engine, front drive) vehicle.

[0018] The pistons reciprocate within the cylinders, causing the crankshaft 7 to rotate via the connecting rods.

[0019] A plurality of intake ports 4a and an exhaust collection portion 4b (see FIG. 4) are formed in the cylinder head 4. In this embodiment, the exhaust collection portion 4b constitutes an exhaust gas outlet.

[0020] The intake ports 4a are connected to the cylinders and introduce intake air into the cylinders. The exhaust collection section 4b is connected to each cylinder through multiple exhaust ports (not shown). That is, the exhaust ports extend from each cylinder to the exhaust collection section 4b, and the exhaust collection section 4b collects the exhaust ports.

[0021] As shown by the imaginary lines in FIG. 3, the cylinder head 4 is provided with a cooling water passage 20, which extends from the right end to the left end of the cylinder head 4.

[0022] Coolant is introduced into the right end of the coolant passage 20 from a coolant passage (not shown) formed in the cylinder block 3. The coolant introduced into the coolant passage 20 flows leftward along the coolant passage 20. In this way, the cylinder head 4 is cooled by the coolant.

[0023] As shown in Figures 2 and 4, the engine 1 has an intake side wall 1A on the side where the intake port 4a opens, and an exhaust side wall 1B located on the opposite side (front side) of the intake side wall 1A and on the side where the exhaust collection section 4b opens.

[0024] The intake side wall 1A is the front wall of the cylinder block 3, cylinder head 4, and cylinder head cover 5 on the side where the intake port 4a opens, and the exhaust side wall 1B is the rear wall of the cylinder block 3, cylinder head 4, and cylinder head cover 5 on the side where the exhaust collection section 4b opens.

[0025] 4, the engine 1 has a cooling water discharge side wall 1C. A cooling water discharge port 4c for discharging the cooling water from the cooling water passage 20 is formed in the cylinder head 4 in the cooling water discharge side wall 1C.

[0026] The cooling water discharge side wall 1C is connected to the left end of the intake side wall 1A and the left end of the exhaust side wall 1B and extends in the front-to-rear direction. A chain cover 50 is attached to the right side wall of the engine 1 opposite the cooling water discharge side wall 1C (see Figure 1).

[0027] 2, an intake manifold 8 is attached to the intake side wall 1A. The intake manifold 8 has a surge tank 8A and a plurality of branch pipes 8B (one shown) corresponding to the number of cylinders.

[0028] For example, if the engine 1 is a three-cylinder engine, three branch pipes 8B are provided. An intake pipe (not shown) is connected to the surge tank 8A via a throttle body (not shown).

[0029] Intake air purified by an air cleaner (not shown) is introduced into the intake pipe, and the intake air is introduced into a surge tank 8A through a throttle body.

[0030] The throttle body accommodates a throttle valve (not shown), which adjusts the amount of intake air introduced into the surge tank 8A.

[0031] The branch pipes 8B extend from the surge tank 8A to each intake port 4a, and distribute the intake air introduced into the surge tank 8A to each intake port 4a.

[0032] As shown in Figures 1 and 2, an exhaust purification device 9 is attached to the intake side wall 1A. Exhaust gas burned in the cylinder is discharged from the cylinder through the exhaust port and collected at the exhaust collection section 4b, and then discharged from the exhaust collection section 4b to the exhaust purification device 9.

[0033] The exhaust purification device 9 purifies the exhaust gas discharged from the exhaust collection section 4b, and discharges the purified exhaust gas into the atmosphere through an exhaust pipe 10 connected to the downstream end of the exhaust purification device 9. In this embodiment, the exhaust purification device 9 and the exhaust pipe 10 form an exhaust passage section.

[0034] The engine 1 is provided with an EGR (Exhaust Gas Recirculation) device 11. The EGR device 11 includes an upstream EGR pipe 12, an EGR cooler 13, an EGR valve 14, and a downstream EGR pipe 15.

[0035] The upstream end of the upstream EGR pipe 12 is connected to the exhaust purification device 9 and branches off from the exhaust purification device 9. Part of the exhaust gas is introduced as EGR gas from the exhaust purification device 9 into the upstream EGR pipe 12. Here, upstream and downstream refer to the upstream and downstream with respect to the flow direction of intake air, exhaust gas, and EGR gas.

[0036] The EGR valve 14 is located downstream of the upstream EGR pipe 12 , and the upstream EGR pipe 12 is located upstream of the EGR valve 14 .

[0037] The EGR cooler 13 is provided adjacent to the exhaust purification device 9 on the exhaust side wall 1B of the engine 1.

[0038] The downstream end of the upstream EGR pipe 12 is connected to the upstream end of the EGR cooler 13. The EGR cooler 13 has an EGR cooler main body 13A through which EGR gas and cooling water flow, a cooling water inlet 13B that introduces the cooling water into the EGR cooler main body 13A, and a cooling water outlet 13C that discharges the cooling water from the EGR cooler 13.

[0039] The EGR cooler 13 cools the EGR gas by exchanging heat between the EGR gas introduced from the upstream EGR pipe 12 and the cooling water.

[0040] The downstream end of the EGR cooler 13 is connected to an EGR valve 14, which is connected to an EGR housing portion 25. The EGR valve 14 adjusts the flow rate of EGR gas flowing through an EGR housing passage portion 26, which will be described later.

[0041] The upstream end of the downstream EGR pipe 15 is connected to the EGR housing part 25, and the EGR gas introduced into the EGR housing part 25 is discharged to the downstream EGR pipe 15. The downstream end of the downstream EGR pipe 15 is connected to the surge tank 8A, and the EGR gas discharged to the downstream EGR pipe 15 is introduced into the surge tank 8A.

[0042] 2 and 5, an EGR housing portion 25, which is separate from the cylinder head 4, is provided at the left end of the cylinder head 4. The EGR housing portion 25 is provided on the left side of the cylinder head cover 5 and is adjacent to the cylinder head cover 5.

[0043] The cylinder head cover 5 is made of resin, and the EGR housing portion 25 is made of metal such as aluminum die-cast.

[0044] As shown in FIG. 5, the EGR housing portion 25 has a front wall 25A, a rear wall 25B, a left side wall 25C, and an upper wall 25D.

[0045] The front wall 25A forms a part of the exhaust side wall 1B of the engine 1, and the rear wall 25B forms a part of the intake side wall 1A of the engine 1. In other words, the front wall 25A is formed on the same side as the exhaust side wall 1B of the engine 1, and the rear wall 25B is located opposite the front wall 25A and is formed on the same side as the intake side wall 1A.

[0046] The left side wall 25C connects the left end of the front wall 25A to the left end of the rear wall 25B, and the top wall 25D connects the upper end of the front wall 25A to the upper end of the rear wall 25B to the upper end of the left side wall 25C. In this embodiment, the left side wall 25C constitutes a connecting wall.

[0047] 5, the EGR housing portion 25 is provided with an EGR housing passage portion 26. The EGR housing passage portion 26 is formed in a cylindrical shape, and has an EGR passage 26a formed therein through which EGR gas flows.

[0048] 2 and 5, the EGR housing passage 26 has an EGR gas inlet 26b and an EGR gas outlet 26c. The EGR gas inlet 26b is provided in the front wall 25A (see FIG. 3), and the EGR gas outlet 26c is provided in the rear wall 25B.

[0049] The EGR gas inlet 26b is an open end on the upstream side of the EGR passage 26a, and the EGR gas outlet 26c is an open end on the downstream side of the EGR passage 26a. The EGR housing passage portion 26 is provided at an angle so that the EGR gas inlet 26b is positioned above the EGR gas outlet 26c.

[0050] The EGR passage 26a is configured as a through-hole that penetrates from the EGR gas inlet 26b to the EGR gas outlet 26c, and the EGR gas inlet 26b is located at a higher position than the EGR gas outlet 26c (see FIG. 2). The EGR passage 26a in this embodiment constitutes a through-hole.

[0051] In this embodiment, the upstream EGR pipe 12, the EGR cooler 13, the EGR housing passage portion 26, and the downstream EGR pipe 15 constitute an EGR passage portion, and a portion of the exhaust gas discharged to the exhaust purification device 9 is returned to the intake manifold 8 through the upstream EGR pipe 12, the EGR cooler 13, the EGR housing passage portion 26, and the downstream EGR pipe 15.

[0052] The EGR housing passage 26 constitutes a head cover EGR passage, the EGR gas inlet 26b constitutes an exhaust side opening, and the EGR gas outlet 26c constitutes an intake side opening.

[0053] 3, a flange portion 27 is provided on the front wall 25A, and the flange portion 27 is provided above the exhaust gas collection portion 4b. An EGR gas inlet port 26b is formed inside the flange portion 27, and the flange portion 27 surrounds the EGR gas inlet port 26b.

[0054] Boss-shaped first and second fastening portions 27A and 27B are provided on flange portion 27. First fastening portion 27A is provided at intersection 29 where front wall 25A and left side wall 25C intersect (see FIG. 5). Second fastening portion 27B is provided on front wall 25A.

[0055] 3, the first fastening portion 27A and the second fastening portion 27B are spaced apart in the left-right direction, and the first fastening portion 27A is provided diagonally below and to the left of the second fastening portion 27B. In other words, the first fastening portion 27A and the second fastening portion 27B are spaced apart in the horizontal direction (left-right direction) and are installed at different height positions.

[0056] The first fastening portion 27A may be located higher than the second fastening portion 27B. That is, the first fastening portion 27A may be provided diagonally above and to the left of the second fastening portion 27B.

[0057] As shown in FIG. 6, a boss portion 25E is provided on the left side wall 25C of the EGR housing portion 25, and the first fastening portion 27A is connected to the boss portion 25E and the EGR housing passage portion .

[0058] Specifically, the EGR housing passage portion 26 has an EGR passage 26a formed as a through-hole therein and is formed in a cylindrical shape surrounding the EGR passage 26a. Therefore, the first fastening portion 27A is connected to the outer wall of the cylindrical EGR housing passage portion 26.

[0059] The boss portion 25E is fastened to the cylinder head 4 by a bolt 33B, and the left side wall 25C is fastened to the cylinder head 4 by the boss portion 25E and the bolt 33B.

[0060] A boss portion 25F is provided on the front wall 25A of the EGR housing portion 25. The boss portion 25F is fastened to the cylinder head 4 by a bolt 33C, and the front wall 25A is fastened to the cylinder head 4 by the boss portion 25F and the bolt 33C.

[0061] A rib 25G is provided on the front wall 25A. The rib 25G extends upward from the boss portion 25F toward the second fastening portion 27B, and connects the boss portion 25F and the second fastening portion 27B.

[0062] In this embodiment, bolt 33B constitutes a first fastener, and bolt 33C constitutes a second fastener. Boss portion 25E constitutes a connecting wall fixing portion, and boss portion 25F constitutes an exhaust side wall fixing portion.

[0063] 1, the EGR valve 14 has an EGR valve main body 14A and a drive portion 14B. An EGR passage portion is formed inside the EGR valve main body 14A, and the EGR passage portion communicates with an EGR housing passage portion 26 and an EGR passage portion formed inside the EGR cooler 13.

[0064] The EGR valve main body 14A is provided with a valve body 14C (see FIG. 2), and the valve body 14C adjusts the opening of the EGR passage portion of the EGR valve main body 14A.

[0065] The drive unit 14B is connected to the EGR valve main body 14A and drives the valve element 14C to adjust the opening of the EGR passage of the EGR valve main body 14A, thereby adjusting the flow rate of EGR gas flowing through the EGR housing passage 26.

[0066] The EGR valve main body 14A is provided with a flange portion 14a, and the EGR valve 14 is fastened to a first fastening portion 27A and a second fastening portion 27B of the flange portion 27 by bolts 33A with the flange portion 14a positioned on the flange portion 27.

[0067] As a result, the EGR valve 14 is attached to the front wall 25A of the EGR housing portion 25 so as to cover the EGR gas inlet port 26b. The bolt 33A in this embodiment constitutes a third fastener. The flange portion 27 constitutes the internal combustion engine side flange portion, and the flange portion 14a constitutes the EGR valve side flange portion.

[0068] The EGR valve 14 of this embodiment is attached to a front wall 25A of the EGR housing portion 25 at a position higher than the exhaust gas collection portion 4b and the exhaust gas purification device 9.

[0069] As shown in FIGS. 2 and 5, a flange portion 28 is provided on the rear wall 25B, and an EGR gas discharge port 26c is formed inside the flange portion 28.

[0070] The flange portion 15a of the downstream EGR pipe 15 is attached to the flange portion 28. An EGR gas inlet (not shown) is provided inside the flange portion 15a, and the EGR gas flowing through the EGR passage 26a is discharged from the EGR gas outlet 26c through the EGR gas inlet of the flange portion 15a to the downstream EGR pipe 15.

[0071] That is, in the engine 1 of this embodiment, an EGR housing portion 25 is attached to the left end of the cylinder head 4 above the cylinder head 4, and EGR gas is introduced from the exhaust side to the intake side through an EGR housing passage portion 26 provided in the EGR housing portion 25.

[0072] The EGR housing portion 25 of this embodiment constitutes a cylinder head cover. The EGR housing portion 25 may be integrated with the cylinder head cover 5, and the EGR housing passage portion 26 may be formed in the cylinder head cover 5.

[0073] 1, when viewed from the front of the engine 1, the EGR valve 14 is installed so that its central axis B is inclined at an angle of approximately 45° with respect to the vertical axis A. The drive unit 14B is installed in a direction away from the exhaust purification device 9 with respect to the EGR valve main body 14A, and the EGR valve main body 14A is installed between the drive unit 14B and the exhaust purification device 9.

[0074] 4, an exhaust cam angle sensor 31 and an intake cam angle sensor 32 are attached to the upper wall 25D of the EGR housing portion 25. The exhaust cam angle sensor 31 detects the rotation angle (rotation phase) of an exhaust camshaft (not shown), and the intake cam angle sensor 32 detects the rotation angle (rotation phase) of an intake camshaft (not shown).

[0075] Next, the effects of the EGR device 11 of the engine 1 of this embodiment will be described. The EGR device 11 of the engine 1 of this embodiment is provided with an upstream EGR pipe 12 that branches off from the exhaust purification device 9 and returns a portion of the exhaust gas flowing through the exhaust purification device 9 to the intake manifold 8 as EGR gas, an EGR cooler 13, an EGR housing passage 26, and a downstream EGR pipe 15, and an EGR valve 14 that adjusts the flow rate of the EGR gas flowing through the EGR housing passage 26.

[0076] In addition, the EGR valve 14 is fastened to a first fastening portion 27A provided at the intersection 29 where the front wall 25A and the left side wall 25C of the EGR housing portion 25 intersect, and to a second fastening portion 27B provided on the front wall 25A.

[0077] Intersection 29 where front wall 25A and left side wall 25C intersect has high rigidity and is resistant to vibration and deformation. Therefore, by fastening EGR valve 14 to at least two locations, namely, first fastening portion 27A provided at highly rigid intersection 29 and second fastening portion 27B provided on front wall 25A, the support rigidity of EGR valve 14 can be increased, thereby suppressing vibration of EGR valve 14.

[0078] As a result, it is possible to suppress a decrease in the control accuracy of the EGR valve 14, thereby improving the reliability of the EGR valve 14. Here, the control accuracy refers to the accuracy of opening and closing the valve body 14C.

[0079] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR housing portion 25 is provided on the left side wall 25C and has a boss portion 25E that attaches the left side wall 25C to the cylinder head 4 with a bolt 33B, and the first fastening portion 27A is connected to the boss portion 25E.

[0080] As a result, the first fastening portion 27A is connected to the boss portion 25E, which has high rigidity and is fastened to the cylinder head 4 by the bolt 33B, and therefore the rigidity of the first fastening portion 27A can be further increased.

[0081] Therefore, by fastening the EGR valve 14 to the first fastening portion 27A, which has higher rigidity, the support rigidity of the EGR valve 14 is further increased, and vibration of the EGR valve 14 can be more effectively suppressed.

[0082] As a result, it is possible to more effectively prevent the control accuracy of the EGR valve 14 from decreasing, and the reliability of the EGR valve 14 can be further improved.

[0083] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR housing portion 25 has a boss portion 25F that is provided on the front wall 25A and that attaches the front wall 25A to the cylinder head 4 with a bolt 33C.

[0084] In addition, the second fastening portion 27B is connected to the boss portion 25F by a rib 25G provided on the front wall 25A.

[0085] As a result, the boss portion 25F, which has high rigidity and is fastened to the cylinder head 4 by the bolt 33C, is connected to the second fastening portion 27B by the rib 25G, which has high rigidity, so that the rigidity of the second fastening portion 27B can be further increased.

[0086] Therefore, by fastening the EGR valve 14 to the second fastening portion 27B, which has an even higher rigidity, the support rigidity of the EGR valve 14 is further increased, and vibration of the EGR valve 14 can be more effectively suppressed.

[0087] As a result, it is possible to more effectively prevent the control accuracy of the EGR valve 14 from decreasing, and the reliability of the EGR valve 14 can be further improved.

[0088] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR housing portion 25 has an EGR housing passage portion 26 that forms part of the EGR passage portion, and the EGR housing passage portion 26 is formed in a cylindrical shape having an EGR passage 26a that runs from an EGR gas inlet port 26b formed in the front wall 25A of the EGR housing portion 25 to an EGR gas outlet port 26c formed in the rear wall 25B.

[0089] In addition, the first fastening portion 27A is connected to the boss portion 25E and the EGR housing passage portion .

[0090] As a result, by connecting the first fastening portion 27A to the EGR housing passage portion 26, which is formed in a cylindrical shape and therefore has high rigidity, and the boss portion 25E, which has high rigidity, the rigidity of the first fastening portion 27A can be further increased.

[0091] Therefore, by fastening the EGR valve 14 to the first fastening portion 27A, which has higher rigidity, the support rigidity of the EGR valve 14 is further increased, and vibration of the EGR valve 14 can be more effectively suppressed.

[0092] As a result, it is possible to more effectively prevent the control accuracy of the EGR valve 14 from decreasing, and the reliability of the EGR valve 14 can be further improved.

[0093] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the first fastening portion 27A and the second fastening portion 27B are spaced apart in the horizontal direction (left-right direction) and are installed at different height positions.

[0094] This effectively prevents the EGR valve 14 from vibrating in the vertical and horizontal directions.

[0095] Specifically, when the first fastening portion 27A and the second fastening portion 27B are installed next to each other vertically, the EGR valve 14 is likely to vibrate left and right. On the other hand, when the first fastening portion 27A and the second fastening portion 27B are installed next to each other horizontally, the EGR valve 14 is likely to vibrate up and down.

[0096] In contrast, if the first fastening portion 27A and the second fastening portion 27B are spaced apart horizontally and installed at different heights, the EGR valve 14 is less likely to vibrate in the vertical and horizontal directions compared to when the first fastening portion 27A and the second fastening portion 27B are installed next to each other vertically or horizontally.

[0097] As a result, it is possible to more effectively prevent the control accuracy of the EGR valve 14 from decreasing, and the reliability of the EGR valve 14 can be further improved.

[0098] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, a flange portion 27 having a first fastening portion 27A and a second fastening portion 27B is provided on the front wall 25A of the EGR housing portion 25, and a flange portion 14a is provided on the EGR valve 14, which abuts against the flange portion 27 and is fastened to the first fastening portion 27A and the second fastening portion 27B by a bolt 33A.

[0099] This allows the flange portion 14a and the flange portion 27 to abut over a wide area, further increasing the support rigidity of the EGR valve 14 and more effectively suppressing vibration of the EGR valve 14.

[0100] As a result, it is possible to more effectively prevent the control accuracy of the EGR valve 14 from decreasing, and the reliability of the EGR valve 14 can be further improved.

[0101] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0102] 1...engine (internal combustion engine), 2...engine body (internal combustion engine body), 3...cylinder block (internal combustion engine body), 4...cylinder head (internal combustion engine body), 5...cylinder head cover (internal combustion engine body), 9...exhaust purification device (exhaust passage portion), 10...exhaust pipe (exhaust passage portion), 11...EGR device, 12...upstream EGR piping (EGR passage portion), 13...EGR cooler (EGR passage portion), 14...EGR valve, 14a...flange portion (EGR valve side flange portion), 15...downstream EGR piping (EGR passage portion), 25...EGR housing portion (cylinder head), 25A...front wall ( exhaust side wall), 25B...rear wall (intake side wall), 25E...boss portion (connection wall fixing portion), 25F...boss portion (exhaust side wall fixing portion), 25G...rib, 26...EGR housing passage portion (EGR passage portion, head cover EGR passage portion), 26a...EGR passage (through hole), 26b...EGR gas inlet (exhaust side opening), 26c...EGR gas outlet (intake side opening), 27...flange portion (internal combustion engine side flange portion), 27A...first fastening portion, 27B...second fastening portion, 29...intersection portion, 33A...bolt (third fastener), 33B...bolt (first fastener), 33C...bolt (second fastener)

Claims

1. an exhaust passage portion provided in an internal combustion engine body having a cylinder head cover and into which exhaust gas discharged from the internal combustion engine body is introduced; an exhaust gas recirculation (EGR) device for an internal combustion engine, wherein the cylinder head cover has an exhaust side wall located on the internal combustion engine main body side where the exhaust passage portion is installed, an intake side wall located on the opposite side to the exhaust side wall, and a connecting wall connecting the exhaust side wall and the intake side wall, an EGR passage portion branched from the exhaust passage portion and configured to recirculate a portion of the exhaust gas flowing through the exhaust passage portion to an intake side of the internal combustion engine body as EGR gas; an EGR valve that adjusts the flow rate of EGR gas flowing through the EGR passage portion, An EGR device for an internal combustion engine, characterized in that the EGR valve is fastened to a first fastening portion provided at the intersection where the exhaust side wall and the connecting wall intersect, and a second fastening portion provided on the exhaust side wall.

2. the cylinder head cover has a connecting wall fixing portion provided on the connecting wall for attaching the connecting wall to the internal combustion engine body with a first fastener, 2. The EGR device for an internal combustion engine according to claim 1, wherein the first fastening portion is connected to the connecting wall fixing portion.

3. the cylinder head cover has an exhaust side wall fixing portion provided on the exhaust side wall for attaching the exhaust side wall to the internal combustion engine body with a second fastener; 3. The EGR device for an internal combustion engine according to claim 1, wherein the second fastening portion is connected to the exhaust side wall fixing portion by a rib provided on the exhaust side wall.

4. the cylinder head cover has a head cover EGR passage portion that constitutes a part of the EGR passage portion, the head cover EGR passage portion has a through-hole that penetrates from an exhaust-side opening formed in the exhaust-side wall of the cylinder head cover to an intake-side opening formed in the intake-side wall, 3. The EGR device for an internal combustion engine according to claim 2, wherein the first fastening portion is connected to the connecting wall fixing portion and the EGR passage portion.

5. 5. The EGR device for an internal combustion engine according to claim 1, wherein the first fastening portion and the second fastening portion are spaced apart in the horizontal direction and are disposed at different height positions.

6. an internal combustion engine side flange portion having the first fastening portion and the second fastening portion is provided on the exhaust side wall, 6. An EGR device for an internal combustion engine according to claim 1, wherein the EGR valve is provided with an EGR valve-side flange portion that abuts against the internal combustion engine-side flange portion and is fastened to the first fastening portion and the second fastening portion by a third fastener.

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