EGR device for internal combustion engines

Abstract

To provide an EGR device for an internal combustion engine capable of inhibiting cooling water flowing in cooling water piping from being affected by heat of an exhaust passage part and thus suppressing deterioration of cooling performance of an EGR cooler.SOLUTION: An EGR device 11 for an engine 1 includes: an EGR cooler 13 provided adjacent to an exhaust emission control device 9 on an exhaust side wall 1B side and constituting part of an EGR passage part; and a cooling water introduction pipe 52 and a cooling water discharge pipe 53 for cooling EGR gas flowing in the EGR cooler 13 by causing cooling water circulating in an engine body 2 to flow via the EGR cooler 13. The cooling water introduction pipe 52 and the cooling water discharge pipe 53 are provided on the side opposite to the exhaust emission control device 9 relative to the EGR cooler 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, there has been known an EGR (Exhaust Gas Recirculation) structure that recirculates part of exhaust gas to the intake side as EGR gas (see Patent Document 1), and this EGR structure includes an EGR cooler that cools the EGR gas.

[0003] The EGR cooler is disposed in a space surrounded by the cylinder block, the exhaust manifold, and the exhaust gas purification device, and is sandwiched between the cylinder block and the exhaust gas purification device in the front-rear direction.

[0004] The EGR cooler is equipped with a coolant inlet pipe that supplies coolant to the EGR cooler and a coolant outlet pipe through which the coolant is discharged from the EGR cooler. The coolant inlet pipe and the coolant outlet pipe are sandwiched between the cylinder block and the exhaust gas purification device in the front-to-rear direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5719376 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in conventional EGR structures, the coolant inlet pipe and the coolant outlet pipe are sandwiched between the cylinder block and the exhaust gas purification device in the front-to-rear direction, so the coolant flowing through the coolant inlet pipe is heated by the heat emitted from the exhaust gas purification device.

[0007] As a result, high-temperature cooling water may be introduced into the EGR cooler through the coolant inlet pipe, which may deteriorate the cooling performance of the EGR cooler.

[0008] 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 suppress the cooling water flowing through the cooling water piping from being affected by the heat of the exhaust passage portion, thereby suppressing a decrease in the cooling performance of the EGR cooler. [Means for solving the problem]

[0009] The present invention provides The internal combustion engine includes a cylinder head having an exhaust side wall and an exhaust gas outlet formed in the exhaust side wall for discharging exhaust gas, and a cylinder head cover attached to an upper part of the cylinder head, and the cylinder head is configured to An EGR device for an internal combustion engine having an exhaust passage section into which exhaust gas is introduced, the device comprising: an EGR passage section branched from the exhaust passage section, for returning a portion of the exhaust gas flowing through the exhaust passage section to an intake side of an internal combustion engine body as EGR gas; an EGR cooler provided adjacent to the exhaust passage section on the exhaust side wall side, and constituting a portion of the EGR passage section; and a cooling water pipe for cooling the EGR gas flowing through the EGR cooler by causing cooling water circulating through the internal combustion engine body to pass through the EGR cooler, The cylinder head cover is provided with a head cover EGR passage portion that constitutes a part of the EGR passage portion, The cooling water pipe is disposed on the opposite side of the EGR cooler from the exhaust passage portion. [Effects of the Invention]

[0010] As described above, according to the present invention, the cooling water flowing through the cooling water pipe is prevented from being affected by the heat of the exhaust passage portion, and the cooling performance of the EGR cooler is prevented from being reduced. [Brief explanation of the drawings]

[0011] [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. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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 passage section on the exhaust side wall side of the internal combustion engine main body into which exhaust gas discharged from the exhaust side wall is introduced, and is equipped with an EGR passage section that branches off from the 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 main body as EGR gas, an EGR cooler that is provided adjacent to the exhaust passage section on the exhaust side wall side and forms a portion of the EGR passage section, and a cooling water piping that cools the EGR gas flowing through the EGR cooler by causing the cooling water circulating through the internal combustion engine main body to pass through the EGR cooler, and the cooling water piping is installed on the opposite side of the EGR cooler from the exhaust passage section.

[0013] As a result, the EGR device for an internal combustion engine according to one embodiment of the present invention can prevent the cooling water flowing through the cooling water piping from being affected by the heat of the exhaust passage portion, thereby preventing a decrease in the cooling performance of the EGR cooler. [Example]

[0014] 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 5 are diagrams showing an EGR device for an internal combustion engine according to one embodiment of the present invention.

[0015] In Figures 1 to 5, the up / down, front / rear, left / right directions are based on the internal combustion engine installed in a vehicle, and the front / rear direction of the vehicle is the front-rear direction, the left / right direction of the vehicle (vehicle width direction) is the left / right direction, and the up / down direction of the vehicle (vehicle height direction) is the up / down direction.

[0016] 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.

[0017] 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.

[0018] 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).

[0019] 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.

[0020] The pistons reciprocate within the cylinders, causing the crankshaft 7 to rotate via the connecting rods.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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, thereby cooling the cylinder head 4. Coolant cooled by a radiator (not shown) is introduced into the coolant passage of the cylinder block from a main pipe (described later).

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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).

[0031] 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.

[0032] The throttle body accommodates a throttle valve (not shown), which adjusts the amount of intake air introduced into the surge tank 8A.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 .

[0039] The EGR cooler 13 is provided adjacent to the exhaust purification device 9 on the exhaust side wall 1B of the engine 1.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] The cylinder head cover 5 is made of resin, and the EGR housing portion 25 is made of metal such as aluminum die-cast.

[0046] 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.

[0047] 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.

[0048] 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 top end of the front wall 25A to the top end of the rear wall 25B to the top end of the left side wall 25C.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The EGR valve main body 14A is provided with a flange 14a, and the EGR valve 14 has the flange 14a fastened to the flange 27 by bolts 33A with the flange 14a positioned on the flange 27.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] In this embodiment, the EGR valve 14 is located above the exhaust collection section 4b and the exhaust purification device 9 and is attached to the front wall 25A of the EGR housing section 25, and the EGR cooler 13 is installed so as to overlap the cooling water outlet 4c in the vertical direction (see Figure 2).

[0064] In other words, the EGR cooler 13 and the cooling water outlet 4c are provided at the same height in the vertical direction and are arranged side by side in the left-right direction.

[0065] 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.

[0066] 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).

[0067] As shown in FIG. 2, a cooling water branching unit 51 is attached to the cooling water discharge side wall 1C, and a cooling water inlet (not shown) of the cooling water branching unit 51 communicates with the cooling water discharge port 4c.

[0068] The cooling water branch unit 51 is provided with a main pipe section 51a, a cooling water inlet pipe section 51b, a heater core pipe section 51c, and an oil cooler pipe section 51d.

[0069] A main pipe is connected to the main pipe section 51a, and the main pipe is connected to a cooling water inlet of the cylinder block 3 and a thermostat 54 (described later). A radiator is attached to the main pipe, and the cooling water flowing through the main pipe is cooled by the radiator.

[0070] The upstream end of a cooling water introduction pipe 52 is connected to the cooling water introduction pipe portion 51 b, and the downstream end of the cooling water introduction pipe 52 is connected to a cooling water introduction portion 13 B of the EGR cooler 13 .

[0071] The cooling water introduction pipe 52 is made of a rubber material or a resin material. The cooling water branching unit 51 introduces the cooling water discharged from the cooling water outlet 4c into the cooling water introduction pipe 52, and the cooling water introduction pipe 52 introduces the cooling water introduced from the cooling water branching unit 51 into the EGR cooler 13.

[0072] The heater core piping section 51c is connected to the upstream end of a heater core piping (not shown) having a heater core (not shown), and the oil cooler piping section 51d is connected to the upstream end of an oil cooler piping (not shown) having an oil cooler (not shown).

[0073] A thermostat 54 is attached to the cooling water discharge side wall 1C. The thermostat 54 is provided with a main pipe section 54a, a cooling water inlet pipe section 54b, a heater core pipe section 54c, and an oil cooler pipe section 54d. A portion 55 of the main pipe is connected downstream of the thermostat 54, and a water pump 56 is attached to the portion 55 of the main pipe.

[0074] The main pipe section 54a is connected to the above-mentioned main pipe. That is, the cooling water introduced from the main pipe into the cooling water passage of the cylinder block 3 is introduced from the cooling water passage of the cylinder block 3 into the cooling water passage 20 of the cylinder head 4, and then introduced from the cooling water outlet 4c through the cooling water branch unit 51 and the cooling water introduction pipe 52 into the EGR cooler 13.

[0075] The cooling water that has cooled the EGR cooler 13 is introduced into a part 55 of the main pipe through a thermostat 54 from a cooling water discharge pipe 53 described later, and is then introduced into the cooling water passage of the cylinder block 3 from a main pipe that is continuous with the part 55 of the main pipe.

[0076] In other words, the main pipe is a pipe that forms a path through which the cooling water discharged from the cooling water outlet 4c is cooled by the radiator and introduced into the inlet of the cooling water passage in the cylinder block 3. Of the main pipes, a portion 55 of the main pipe that is connected to the thermostat 54 is shown in Figure 2.

[0077] The downstream end of the cooling water discharge pipe 53 is connected to the cooling water inlet pipe portion 54b, and the upstream end of the cooling water discharge pipe 53 is connected to the cooling water discharge portion 13C of the EGR cooler 13. The cooling water discharge pipe 53 is made of a rubber material or a resin material. The cooling water discharge pipe 53 flows high-temperature cooling water that has cooled the EGR cooler 13 from the EGR cooler 13 to the thermostat 54.

[0078] When the temperature of the coolant reaches or exceeds a predetermined temperature, the thermostat 54 causes the coolant to flow through the main pipe to the radiator, and the coolant cooled by the radiator is circulated to the engine 1. The coolant that has cooled the engine 1 is introduced from the coolant branch unit 51 through the coolant introduction pipe 52 into the EGR cooler 13, thereby cooling the EGR cooler 13.

[0079] The heater core pipe section 54c is connected to the downstream end of the heater core pipe described above, and the oil cooler pipe section 54d is connected to the downstream end of the oil cooler pipe described above.

[0080] In the engine 1 of this embodiment, when the water pump 56 is driven, cooling water flows through the main piping, circulating between the cylinder block 3, the cylinder head 4, the EGR cooler 13 and the radiator, and also circulating through the heater core piping and the oil cooler piping.

[0081] That is, the EGR device 11 cools the EGR gas flowing through the EGR cooler 13 by causing the cooling water circulating through the cylinder block 3 and the cylinder head 4 of the engine 1 to pass through the EGR cooler 13. The cooling water inlet pipe 52 and the cooling water outlet pipe 53 in this embodiment constitute a cooling water piping.

[0082] The water pump 56 in this embodiment is an electric pump. The water pump 56 may be driven by the crankshaft 7 of the engine 1.

[0083] 1 and 2, the cooling water inlet pipe 52 and the cooling water outlet pipe 53 are installed on the opposite side of the EGR cooler 13 from the exhaust purification device 9. In other words, the EGR cooler 13 is installed between the exhaust purification device 9 and the cooling water inlet pipe 52 and the cooling water outlet pipe 53.

[0084] The EGR cooler main body 13A is formed in a rectangular parallelepiped shape that extends along the direction in which the exhaust purification device 9 extends (the vertical direction).

[0085] The EGR cooler main body 13A has a front wall 13a, a rear wall 13b, a left side wall 13c, and a right side wall 13d. The right side wall 13d faces the exhaust purification device 9, and the left side wall 13c faces the opposite side of the right side wall 13d from the exhaust purification device 9.

[0086] The front wall 13a and the rear wall 13b connect the front and rear ends (both widthwise ends) of the left side wall 13c and the right side wall 13d, respectively. In this embodiment, the right side wall 13d constitutes the first side wall, and the left side wall 13c constitutes the second side wall. The front wall 13a constitutes the third side wall, and the rear wall 13b constitutes the fourth side wall.

[0087] In the EGR cooler main body 13A, the areas of the left side wall 13c and the right side wall 13d are larger than the areas of the front wall 13a and the rear wall 13b, and a cooling water inlet section 13B and a cooling water outlet section 13C are provided on the right side wall 13d.

[0088] That is, the EGR cooler main body 13A covers the exhaust purification device 9 with respect to the cooling water inlet section 13B and the cooling water outlet section 13C, and the cooling water inlet section 13B and the cooling water outlet section 13C are thermally insulated from the exhaust purification device 9 by the EGR cooler main body 13A.

[0089] 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 branched off from the exhaust purification device 9 and includes an upstream EGR pipe 12, an EGR housing passage portion 26, and a downstream EGR pipe 15 that recirculates a portion of the exhaust gas flowing through the exhaust purification device 9 to the intake manifold 8 of the engine body 2 as EGR gas.

[0090] The EGR device 11 is provided adjacent to the exhaust purification device 9 on the exhaust side wall 1B side, and is equipped with an EGR cooler 13 that forms part of the EGR passage, and a cooling water inlet pipe 52 and a cooling water outlet pipe 53 that cool the EGR gas flowing through the EGR cooler 13 by causing the cooling water circulating in the engine body 2 to pass through the EGR cooler 13, and the cooling water inlet pipe 52 and the cooling water outlet pipe 53 are installed on the opposite side of the EGR cooler 13 from the exhaust purification device 9.

[0091] This allows the cooling water introduction pipe 52 to be installed at a position away from the exhaust purification device 9, and prevents the cooling water flowing through the cooling water introduction pipe 52 from being affected by the heat of the exhaust purification device 9. This prevents the temperature of the cooling water introduced into the EGR cooler 13 from rising.

[0092] In addition, since the cooling water flows inside the EGR cooler 13, the exhaust heat can be blocked by the cooling water flowing through the EGR cooler 13. Therefore, the transfer of heat from the EGR cooler 13 to the cooling water introduction pipe 52 can be suppressed.

[0093] Therefore, before the cooling water is introduced into the EGR cooler 13, the cooling water flowing through the cooling water introduction pipe 52 can be more effectively prevented from being affected by the heat of the exhaust purification device 9.

[0094] As a result of the above, the EGR gas flowing through the EGR cooler 13 can be stably cooled, and the cooling performance of the EGR cooler 13 can be prevented from decreasing.

[0095] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the EGR cooler 13 has an EGR cooler main body 13A that cools the EGR gas flowing through the EGR cooler 13, a cooling water inlet portion 13B that is provided in the EGR cooler main body 13A and connected to the cooling water inlet pipe 52, and a cooling water outlet portion 13C that is provided in the EGR cooler main body 13A and connected to the cooling water outlet pipe 53.

[0096] The EGR cooler main body 13A has a rectangular parallelepiped shape extending along the extension direction of the exhaust purification device 9, and has a right side wall 13d facing the exhaust purification device 9, a left side wall 13c facing the opposite side of the exhaust purification device 9 from the right side wall 13d, and a front wall 13a and a rear wall 13b connecting both widthwise ends of the left side wall 13c and the right side wall 13d.

[0097] The areas of the left and right walls 13c, 13d are larger than the areas of the front and rear walls 13a, 13b, and the left wall 13c is provided with a cooling water inlet 13B and a cooling water outlet 13C.

[0098] As a result, by opposing the right side wall 13d, which has a larger area than the front wall 13a and the rear wall 13b, over a wide range of the exhaust purification device 9, the exhaust purification device 9 can be covered by the EGR cooler main body 13A, and the cooling water inlet section 13B and the cooling water outlet section 13C can be thermally insulated from the exhaust purification device 9 by the EGR cooler main body 13A.

[0099] Therefore, the cooling water flowing through the cooling water introduction pipe 52 can be more effectively prevented from being affected by the heat of the exhaust purification device 9, and the cooling performance of the EGR cooler 13 can be more effectively prevented from decreasing.

[0100] Furthermore, according to the EGR device 11 of the engine 1 of this embodiment, the engine body 2 has a cylinder head 4 having an exhaust side wall 1B, in which an exhaust collection section 4b that discharges exhaust gas is formed on the exhaust side wall 1B, and an EGR housing section 25 having a front wall 25A and attached to the upper part of the cylinder head 4.

[0101] The EGR housing portion 25 is provided with an EGR housing passage portion 26 that constitutes a part of the EGR passage portion, and the cylinder head 4 is provided with a cooling water outlet 4c that discharges cooling water into the cooling water introduction pipe 52.

[0102] The EGR device 11 is attached to the front wall 25A of the EGR housing portion 25 and has an EGR valve 14 that adjusts the flow rate of EGR gas flowing through the EGR housing passage portion 26, and the EGR cooler 13 is installed so as to overlap the cooling water outlet 4c in the vertical direction.

[0103] This allows the EGR valve 14 to be attached to the EGR housing portion 25 that is installed at the highest position in the engine 1 , and the EGR cooler 13 to be installed above the engine 1 .

[0104] Therefore, the EGR cooler 13 can be installed at the same height as the cooling water outlet 4c of the cylinder head 4, and the cooling water inlet pipe 52 and the cooling water outlet pipe 53 can be installed extending in the front-to-rear direction rather than extending long in the up-down and left-to-right directions.

[0105] As a result, the cooling water inlet pipe 52 and the cooling water outlet pipe 53 can be shortened, and the installation space for the cooling water inlet pipe 52 and the cooling water outlet pipe 53 can be reduced, thereby reducing the installation space for the engine 1.

[0106] Furthermore, the cooling water inlet pipe 52 and the cooling water outlet pipe 53 of this embodiment are made of rubber or resin material, so that deterioration due to heat can be suppressed.

[0107] 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]

[0108] 1...engine (internal combustion engine), 1B...exhaust side wall, 2...engine body (internal combustion engine body), 4...cylinder head, 4b...exhaust collection section (exhaust gas outlet), 4c...coolant outlet, 9...exhaust 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), 13A...EGR cooler body section, 13a.. .Front wall (third side wall), 13B...cooling water inlet portion, 13b...rear wall (fourth side wall), 13C...cooling water outlet portion, 13c...left side wall (second side wall), 13d...right side wall (first side wall), 14...EGR valve, 15...downstream EGR piping (EGR passage portion), 25...EGR housing portion (cylinder head), 25A...front wall (exhaust side wall), 26...EGR housing passage portion (EGR passage portion, head cover EGR passage portion)

Claims

1. An internal combustion engine body having a cylinder head with an exhaust side wall, an exhaust gas outlet formed in the exhaust side wall for discharging exhaust gas, and a cylinder head cover attached to an upper part of the cylinder head, The cylinder head is an EGR device for an internal combustion engine having an exhaust passage portion into which exhaust gas discharged from the exhaust gas outlet is introduced, an EGR passage portion branched from the exhaust passage portion, for recirculating 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 cooler provided adjacent to the exhaust passage portion on the exhaust side wall side and constituting a part of the EGR passage portion; a cooling water pipe that causes cooling water circulating in the internal combustion engine body to flow through the EGR cooler, thereby cooling the EGR gas flowing through the EGR cooler, a head cover EGR passage portion that constitutes a part of the EGR passage portion is provided in the cylinder head cover, The EGR device for an internal combustion engine, wherein the cooling water pipe is installed on an opposite side of the EGR cooler from the exhaust passage portion.

2. the cooling water piping includes a cooling water inlet pipe that introduces cooling water into the EGR cooler and a cooling water outlet pipe that discharges cooling water from the EGR cooler, the EGR cooler includes an EGR cooler main body that cools the EGR gas flowing through the EGR cooler, a cooling water inlet provided in the EGR cooler main body and connected to the cooling water pipe, and a cooling water outlet provided in the EGR cooler main body and connected to the cooling water pipe, The EGR cooler main body is formed in a rectangular parallelepiped shape extending along the direction in which the exhaust passage portion extends, and has a first side wall facing the exhaust passage portion, a second side wall facing the opposite side of the first side wall from the exhaust passage portion, and a third side wall and a fourth side wall connecting both end portions of the first side wall and the second side wall in a width direction, the first side wall and the second side wall have areas larger than the third side wall and the fourth side wall; 2. The EGR device for an internal combustion engine according to claim 1, wherein the second side wall is provided with the cooling water inlet and the cooling water outlet.

3. a cooling water outlet port for discharging cooling water into the cooling water inlet pipe is provided in the cylinder head, the EGR device has an EGR valve attached to the exhaust side wall of the cylinder head cover and adjusting the flow rate of EGR gas flowing through the EGR passage portion, 3. The EGR device for an internal combustion engine according to claim 2, wherein the EGR cooler and the cooling water outlet are arranged so that their vertical positions are aligned in a horizontal direction perpendicular to the vertical direction.

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