EGR system for internal combustion engines

Abstract

To provide an EGR device for an internal combustion engine capable of inhibiting an EGR valve from being affected by exhaust heat.SOLUTION: An EGR device 11 for an engine 1 includes an EGR valve 14 for controlling a flow rate of EGR gas flowing in an EGR housing passage part 26. The EGR valve 14 is located above an exhaust gas collecting part 4b and an exhaust emission control device 9 and is mounted to a front wall 25A of an EGR housing part 25.SELECTED DRAWING: Figure 1

Description

Technical Field

[0003]

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

Background Art

[0002] Conventionally, an internal combustion engine equipped with an EGR (Exhaust Gas Recirculation) device has been known (see Patent Document 1).

[0003] This internal combustion engine includes an exhaust manifold connected to the front of the internal combustion engine and extending downward from the internal combustion engine, an exhaust purification device and an exhaust pipe, an intake manifold connected to the rear of the internal combustion engine, an EGR passage portion that connects the exhaust purification device and the intake manifold and recirculates a part of the exhaust gas discharged from the internal combustion engine to the exhaust purification device to the intake manifold, and an EGR valve attached to the cylinder head and adjusting the flow rate of the EGR gas flowing through the EGR passage portion.

[0004] The EGR valve is adjacent to the exhaust manifold on the front surface of the internal combustion engine and is installed at the same height position as the exhaust manifold.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the conventional engine, since the EGR valve is installed adjacent to the exhaust manifold on the front surface of the internal combustion engine, the EGR valve is easily affected by the exhaust heat generated from the exhaust manifold, and there is still room for improvement.

[0007] This invention has been made in view of the circumstances described above, and aims to provide an EGR system for an internal combustion engine that can suppress the effects of exhaust heat on the EGR valve. [Means for solving the problem]

[0008] The present invention relates to an EGR device for an internal combustion engine having an exhaust gas outlet formed in the exhaust side wall of the internal combustion engine body and an exhaust passage connected to the exhaust gas outlet and into which exhaust gas discharged from the exhaust gas outlet is introduced, comprising: an EGR passage branched off from the exhaust passage and returning a portion of the exhaust gas flowing through the exhaust passage to the intake side of the internal combustion engine body as EGR gas; and an EGR valve that adjusts the flow rate of the EGR gas flowing through the EGR passage, wherein the EGR valve is mounted on the exhaust side wall of the internal combustion engine body and is located above the exhaust gas outlet and the exhaust passage. The EGR valve comprises an EGR valve body having a valve element that adjusts the flow rate of EGR gas flowing through the EGR passage, and a drive unit attached to the EGR valve body for driving the valve element. In a front view of the internal combustion engine body, the EGR valve is installed at an inclination such that the drive unit is away from the exhaust passage, with respect to a vertical axis passing through the EGR valve body, where the central axis passing through the center of the EGR valve is located. It is characterized by being. [Effects of the Invention]

[0009] As described above, according to the present invention, it is possible to suppress the effect of exhaust heat on the EGR valve. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a front view of an internal combustion engine equipped with an EGR device according to one embodiment of the present invention. [Figure 2] Figure 2 is a left side view of an internal combustion engine equipped with an EGR device according to one embodiment of the present invention. [Figure 3] Figure 3 is a front view of the cylinder head and cylinder head cover of an internal combustion engine according to one embodiment of the present invention. [Figure 4] Figure 4 is a left side view of the cylinder head and cylinder head cover of an internal combustion engine according to one embodiment of the present invention. [Figure 5] Figure 5 is a plan view of the EGR housing portion of an internal combustion engine according to one embodiment of the present invention. [Figure 6]Figure 6 is a perspective view of the front wall side of the EGR housing portion of an internal combustion engine according to one embodiment of the present invention. [Modes for carrying out the invention]

[0011] An EGR device for an internal combustion engine according to one embodiment of the present invention is an EGR device for an internal combustion engine having an exhaust gas exhaust port formed in the exhaust side wall of the internal combustion engine body and an exhaust passage connected to the exhaust gas exhaust port into which exhaust gas discharged from the exhaust gas exhaust port is introduced, comprising an EGR passage branched off from the exhaust passage and returning a portion of the exhaust gas flowing through the exhaust passage to the intake side of the internal combustion engine body as EGR gas, and an EGR valve that adjusts the flow rate of the EGR gas flowing through the EGR passage, wherein the EGR valve is located above the exhaust gas exhaust port and the exhaust passage and is mounted on the exhaust side wall of the internal combustion engine.

[0012] As a result, the EGR device for an internal combustion engine according to one embodiment of the present invention can suppress the effect of exhaust heat on the EGR valve. [Examples]

[0013] Hereinafter, an EGR device for an internal combustion engine according to one embodiment of the present invention will be described with reference to the drawings. Figures 1 to 6 show an EGR device for an internal combustion engine according to one embodiment of the present invention. In Figures 1 to 6, the vertical, horizontal, front-rear, and left-right directions are based on the internal combustion engine installed in the vehicle, with the front-rear direction of the vehicle being the front-rear direction, the left-right direction of the vehicle (vehicle width direction) being the left-right direction, and the vertical direction of the vehicle (vehicle height direction) being the vertical direction.

[0014] First, let me explain the structure. In Figure 1, an engine 1 is provided in the engine compartment of the vehicle (not shown). The engine 1 has an engine body 2, which consists 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] The cylinder head 4 is attached to the upper part of the cylinder block 3, and the cylinder head cover 5 is attached to the upper part of the cylinder head 4. The oil pan 6 is attached to the lower part of the cylinder block 3, and the 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), and the cylinders are arranged in the vehicle width direction. Pistons (not shown) are respectively accommodated in the cylinders, and the pistons are connected to the crankshaft 7 (see FIG. 2) via connecting rods (not shown).

[0017] The engine 1 of the present embodiment is a horizontally-mounted engine in which the crankshaft 7 extends in the vehicle width direction, and the vehicle is a FF (front engine · front drive) vehicle.

[0018] By reciprocating in the cylinder, the piston rotates the crankshaft 7 via the connecting rod.

[0019] A plurality of intake ports 4a and an exhaust collecting portion 4b (see FIG. 4) are formed in the cylinder head 4. The exhaust collecting portion 4b of the present embodiment constitutes an exhaust gas exhaust port.

[0020] The intake ports 4a communicate with the cylinders respectively and introduce the intake air into the cylinders. The exhaust collecting portion 4b communicates with each cylinder through a plurality of exhaust ports (not shown). That is, the exhaust ports extend from each cylinder to the exhaust collecting portion 4b, and the exhaust collecting portion 4b collects the exhaust ports.

[0021] As shown by the virtual line in FIG. 3, a cooling water passage 20 is provided in the cylinder head 4, and the cooling water passage 20 extends from the right end portion to the left end portion of the cylinder head 4.

[0022] Cooling water is introduced into the right end of the cooling water passage 20 from a cooling water passage (not shown) formed in the cylinder block 3. The cooling water introduced into the cooling water passage 20 flows to the left along the passage 20. As a result, the cylinder head 4 is cooled by the cooling water.

[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) from the intake side wall 1A, on the side where the exhaust manifold 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 manifold 4b opens.

[0025] As shown in Figure 4, the engine 1 has a coolant discharge side wall 1C. In the coolant discharge side wall 1C, the cylinder head 4 has a coolant discharge port 4c formed therein for discharging coolant from the coolant passage 20.

[0026] The coolant 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-rear direction. A chain cover 50 is attached to the right side wall of the engine 1, opposite to the coolant discharge side wall 1C (see Figure 1).

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

[0028] For example, if engine 1 is a three-cylinder engine, there are three branch pipes 8B. 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 manifold, and the intake air is then introduced into the surge tank 8A through the throttle body.

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

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

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

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

[0034] Engine 1 is equipped with an EGR (Exhaust Gas Recirculation) device 11. The EGR device 11 comprises 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 gas purification device 9 and branches off from the exhaust gas purification device 9. A portion of the exhaust gas from the exhaust gas purification device 9 is introduced into the upstream EGR pipe 12 as EGR gas. Here, upstream and downstream refer to the upstream and downstream directions in relation to the flow 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 installed 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 piping 12 is connected to the upstream end of the EGR cooler 13. The EGR cooler 13 has an EGR cooler body 13A through which EGR gas and cooling water flow, a cooling water inlet 13B for introducing cooling water into the EGR cooler body 13A, and a cooling water outlet 13C for discharging cooling water from the EGR cooler 13.

[0039] The EGR cooler 13 cools the EGR gas introduced from the upstream EGR pipe 12 by exchanging heat between the EGR gas and 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 25. The EGR valve 14 adjusts the flow rate of EGR gas flowing through the EGR housing passage 26, which will be described later.

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

[0042] As shown in Figures 2 and 5, an EGR housing section 25, separate from the cylinder head 4, is provided at the left end of the cylinder head 4. The EGR housing section 25 is located to the left 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 section 25 is made of metal such as aluminum die-cast.

[0044] As shown in Figure 5, the EGR housing section 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 part of the exhaust side wall 1B of the engine 1, and the rear wall 25B forms 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 on the opposite side from 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 upper 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] As shown in Figure 5, the EGR housing section 25 is provided with an EGR housing passage section 26. The EGR housing passage section 26 is formed in a cylindrical shape, and an EGR passage 26a is formed inside through which EGR gas flows.

[0048] As shown in Figures 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 on the front wall 25A (see Figure 3), and the EGR gas outlet 26c is provided on the rear wall 25B.

[0049] The EGR gas inlet 26b is the upstream opening end of the EGR passage 26a, and the EGR gas outlet 26c is the downstream opening end of the EGR passage 26a. The EGR housing passage 26 is inclined so that the EGR gas inlet 26b is located above the EGR gas outlet 26c.

[0050] The EGR passage 26a is composed of a through-hole that extends from the EGR gas inlet 26b to the EGR gas outlet 26c, with the EGR gas inlet 26b located higher than the EGR gas outlet 26c (see Figure 2). In this embodiment, the EGR passage 26a constitutes a through-hole.

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

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

[0053] As shown in Figure 3, a flange portion 27 is provided on the front wall 25A, and the flange portion 27 is located above the exhaust manifold 4b. An EGR gas inlet 26b is formed inside the flange portion 27, and the flange portion 27 surrounds the EGR gas inlet 26b.

[0054] The flange portion 27 is provided with a boss-shaped first fastening portion 27A and a second fastening portion 27B. The first fastening portion 27A is provided at the intersection 29 where the front wall 25A and the left side wall 25C meet (see Figure 5). The second fastening portion 27B is provided on the front wall 25A.

[0055] As shown in Figure 3, the first fastening portion 27A and the second fastening portion 27B are separated in the left-right direction, and the first fastening portion 27A is located 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 separated in the horizontal direction (left-right direction) and are installed at different height positions.

[0056] Furthermore, the first fastening portion 27A may be located above 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 Figure 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 26.

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

[0059] The boss portion 25E is fastened to the cylinder head 4 by bolts 33B, and the left side wall 25C is fastened to the cylinder head 4 by the boss portion 25E and bolts 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 bolts 33C, and the front wall 25A is fastened to the cylinder head 4 by the boss portion 25F and bolts 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, connecting the boss portion 25F and the second fastening portion 27B.

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

[0063] As shown in Figure 1, the EGR valve 14 has an EGR valve body 14A and a drive unit 14B. Inside the EGR valve body 14A, there is an EGR passage that connects the EGR passage formed inside the EGR cooler 13 with the EGR housing passage 26.

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

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

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

[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 26b. In this embodiment, the bolt 33A 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] In this embodiment, the EGR valve 14 is located above the exhaust manifold 4b and the exhaust purification device 9 and is mounted on the front wall 25A of the EGR housing 25.

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

[0070] The flange portion 28 is fitted with the flange portion 15a of the downstream EGR piping 15. 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 piping 15.

[0071] In other words, in this embodiment, the engine 1 has an EGR housing 25 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 26 provided in the EGR housing 25.

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

[0073] As shown in Figure 1, in a front view of the engine 1, the EGR valve 14 is installed such 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 away from the exhaust gas purification device 9 relative to the EGR valve body 14A, and the EGR valve body 14A is installed between the drive unit 14B and the exhaust gas purification device 9.

[0074] As shown in Figure 4, an exhaust cam angle sensor 31 and an intake cam angle sensor 32 are mounted on the upper wall 25D of the EGR housing 25. The exhaust cam angle sensor 31 detects the rotation angle (rotation phase) of the exhaust cam shaft (not shown), and the intake cam angle sensor 32 detects the rotation angle (rotation phase) of the intake cam shaft (not shown).

[0075] Next, the effects of the EGR device 11 of the engine 1 in this embodiment will be explained. The EGR device 11 of the engine 1 in this embodiment is equipped with an EGR valve 14 that adjusts the flow rate of EGR gas through the EGR housing passage 26. The EGR valve 14 is located above the exhaust manifold 4b and the exhaust purification device 9 and is mounted on the front wall 25A of the EGR housing 25.

[0076] This prevents the EGR valve 14 from being affected by the radiant heat of the exhaust gas flowing through the exhaust gas purification device 9. As a result, the durability of the EGR valve 14 can be improved. In addition, since the EGR valve 14 is protected from heat, a decrease in the control accuracy of the drive unit 14B can be prevented. Here, control accuracy refers to the accuracy of opening and closing the valve body 14C.

[0077] Furthermore, since the EGR device 11 can be installed adjacent to the exhaust gas purification device 9 on its side, the dead space on the side of the exhaust gas purification device 9 can be effectively utilized, while suppressing the EGR valve 14 from being affected by the radiant heat of the exhaust gas flowing through the exhaust gas purification device 9. As a result, the engine 1 can be made smaller.

[0078] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR valve 14 has an EGR valve body 14A having a valve body 14C that adjusts the flow rate of EGR gas flowing through the EGR housing passage 26, and a drive unit 14B attached to the EGR valve body 14A that drives the valve body 14C.

[0079] When the drive unit 14B, which drives the valve body 14C, is affected by the heat of the EGR valve body 14A through which high-temperature EGR gas flows, the control accuracy of the drive unit 14B is easily degraded.

[0080] In this embodiment, the EGR valve 14 is installed such that the drive unit 14B is separated from the exhaust gas purification device 9 relative to the EGR valve body 14A.

[0081] Therefore, the drive unit 14B can be installed further away from the exhaust gas purification device 9, and the drive unit 14B can be more effectively protected from the effects of radiant heat from the exhaust gas flowing through the exhaust gas purification device 9.

[0082] Therefore, in addition to improving the durability of the EGR valve 14, the drive unit 14B can be protected from heat, and the control accuracy of the drive unit 14B can be more effectively prevented from deteriorating.

[0083] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR housing section 25 is provided with an EGR housing passage section 26 which constitutes a part of the EGR passage section, and the EGR valve 14 is attached to the front wall 25A of the EGR housing section 25.

[0084] In other words, in the EGR device 11 of this embodiment, an EGR housing passage 26 is formed in the EGR housing section 25 adjacent to the cylinder head cover 5, which is located at the highest position in the engine 1, and EGR gas is recirculated from the exhaust side to the intake side via the EGR housing section 25.

[0085] This allows the EGR valve 14 to be installed further away from the exhaust gas purification device 9, and more effectively suppresses the EGR valve 14 from being affected by the radiant heat of the exhaust gas flowing through the exhaust gas purification device 9.

[0086] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR housing portion 25 has a front wall 25A and a rear wall 25B on the opposite side.

[0087] The EGR housing passage section 26 has an EGR passage 26a that penetrates from an EGR gas inlet 26b formed in the front wall 25A of the EGR housing section 25 to an EGR gas outlet 26c formed in the rear wall 25B.

[0088] In addition, the EGR valve 14 is mounted on the front wall 25A so as to cover the EGR gas inlet 26b, and the height of the EGR gas outlet 26c is located higher than the height of the EGR gas outlet 26c.

[0089] This allows the EGR valve 14 to be installed at a high position away from the exhaust gas purification device 9, and more effectively suppresses the EGR valve 14 from being affected by the radiant heat of the exhaust gas flowing through the exhaust gas purification device 9.

[0090] Therefore, in addition to more effectively improving the durability of the EGR valve 14, it is also possible to more effectively protect the EGR valve 14 from heat and prevent a decrease in the control accuracy of the drive unit 14B.

[0091] While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims. [Explanation of Symbols]

[0092] 1...Engine (internal combustion engine), 1B...Exhaust side wall, 4...Cylinder head, 4b...Exhaust manifold (exhaust gas outlet), 9...Exhaust gas purification device (exhaust passage section), 10...Exhaust pipe (exhaust passage section), 11...EGR device, 12...Upstream EGR piping (EGR passage section), 13...EGR cooler (EGR passage section), 14...EGR valve, 14A...EGR valve body, 14B...Drive unit, 14C...Valve body, 15...Downstream EGR piping (EGR passage section), 25...EGR housing section (cylinder head), 25A...Front wall (exhaust side wall), 25B...Rear wall (intake side wall), 26...EGR housing passage section (EGR passage section, head cover EGR passage section), 26a...EGR passage (through hole), 26b...EGR gas inlet (exhaust side opening), 26c...EGR gas outlet (intake side opening)

Claims

1. An EGR system for an internal combustion engine having an exhaust gas outlet formed in the exhaust side wall of the internal combustion engine body, and an exhaust passage connected to the exhaust gas outlet into which exhaust gas discharged from the exhaust gas outlet is introduced, An EGR passage section is branched off from the aforementioned exhaust passage section and returns a portion of the exhaust gas flowing through the exhaust passage section to the intake side of the internal combustion engine body as EGR gas. The system includes an EGR valve that adjusts the flow rate of EGR gas flowing through the EGR passage, The EGR valve is mounted on the exhaust side wall of the internal combustion engine body, positioned above the exhaust gas outlet and the exhaust passage. The aforementioned EGR valve is The EGR valve has a valve body that adjusts the flow rate of EGR gas flowing through the EGR passage, and a drive unit that is attached to the EGR valve body and drives the valve body. An EGR device for an internal combustion engine, characterized in that, in a front view of the internal combustion engine body, the EGR valve is installed at an inclination such that the drive unit moves away from the exhaust passage portion, with respect to the vertical axis passing through the EGR valve body portion, where the central axis passing through the center of the EGR valve is located.

2. The internal combustion engine body comprises a cylinder head having the exhaust gas outlet and a cylinder head cover attached to the upper part of the cylinder head. The cylinder head cover is provided with a head cover EGR passage section that constitutes a part of the EGR passage section, The EGR device for an internal combustion engine according to claim 1, characterized in that the EGR valve is attached to the exhaust side wall of the cylinder head cover.

3. The cylinder head cover has an intake side wall provided on the opposite side of the exhaust side wall, The head cover EGR passage is formed in a cylindrical shape having a through hole that penetrates from the exhaust side opening formed in the exhaust side wall of the cylinder head cover to the intake side opening formed in the intake side wall. The EGR valve is mounted on the exhaust side wall so as to cover the exhaust side opening. The EGR device for an internal combustion engine according to claim 2, characterized in that the height of the exhaust side opening is located higher than the height of the intake side opening.

Images