Cooling structure of exhaust collection pipe

Abstract

To provide a cooling structure of an exhaust collection pipe which takes into consideration a temperature difference between an upper part and a lower part of the exhaust collection pipe.SOLUTION: A cooling structure of an exhaust collection pipe has a plurality of connection ports in which a plurality of exhaust ports are arranged at a cylinder head extending in a longitudinal direction, and which are connected to the plurality of exhaust ports, respectively, and a collection part arranged at a downstream side of exhaust flows of the connection ports, and collecting the plurality of connection ports. The cooling structure of the exhaust collection pipe comprises a cooling passage for covering the connection ports and the collection part, and the cooling passage has a first cooling passage for covering an upper part of the exhaust collection pipe, a second cooling passage for covering a lower part of the exhaust collection pipe, and a division wall arranged in a boundary between the first cooling passage and the second cooling passage. A volume of the first cooling passage is smaller than a volume of the second cooling passage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a cooling structure for an exhaust manifold. [Background technology]

[0002] Structures for cooling exhaust manifolds have been known for some time (see, for example, Patent Document 1). In the cooling structure for exhaust manifolds in Patent Document 1, a cooling passage is provided that covers the exhaust manifold, and the exhaust manifold is cooled by cooling water that flows through the cooling passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-151024 A Summary of the Invention [Problem to be solved by the invention]

[0004] Heat tends to build up in the lower part of the exhaust manifold. This makes the temperature higher at the lower part than at the upper part. This means that the lower part of the exhaust manifold needs to be cooled more. The cooling structure for the exhaust manifold in Patent Document 1 does not take into account the temperature difference between the top and bottom of the exhaust manifold.

[0005] An object of the present disclosure is to provide a cooling structure for an exhaust manifold that takes into account the temperature difference between the top and bottom of the exhaust manifold. [Means for solving the problem]

[0006] The cooling structure for an exhaust collector pipe according to the present disclosure is a cooling structure for an exhaust collector pipe having a plurality of exhaust ports provided in a cylinder head extending in the longitudinal direction, a plurality of connection ports connected to each of the plurality of exhaust ports, and a collecting section provided downstream of the connection ports in the exhaust flow and collecting the plurality of connection ports. The cooling structure for the exhaust collector pipe includes a cooling passage covering the connection ports and the collecting section, the cooling passage having a first cooling passage covering an upper portion of the exhaust collector pipe, a second cooling passage covering a lower portion of the exhaust collector pipe, and a dividing wall provided at the boundary between the first cooling passage and the second cooling passage, and the volume of the first cooling passage is larger than the volume of the second cooling passage. Effect of the Invention

[0007] This exhaust manifold cooling structure allows the upper and lower parts of the exhaust manifold to be cooled independently. Furthermore, because the volume of the lower cooling passage is larger than that of the upper part, the lower part, where the cooling water temperature is more likely to be high, can be cooled more than the upper part. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of an exhaust manifold according to one embodiment of the present disclosure; [Diagram 2] FIG. 2 is a side view of an exhaust manifold according to one embodiment of the present disclosure. [Diagram 3] Cross section AA of Figure 3. [Figure 4] Cross-sectional view taken along line B-B in Figure 3. [Diagram 5] FIG. 2 is a diagram of a first cooling passage according to one embodiment of the present disclosure. [Figure 6] FIG. 4 is a diagram of a second cooling passage according to one embodiment of the present disclosure. [Figure 7] 1 is a cooling circuit diagram of an internal combustion engine using an exhaust manifold cooling structure according to an embodiment of the present disclosure; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the following specification and drawings, the longitudinal direction of a cylinder head 6 is indicated as L, the lateral direction as S, and the up-down direction as U.

[0010] As shown in Fig. 1, the cooling structure 1 for an exhaust manifold M has a plurality of connection ports 2 and a collecting section 4. The connection ports 2 are connected to a plurality of exhaust ports 8 provided in a cylinder head 6 extending in a longitudinal direction L. The collecting section 4 is provided downstream of the connection ports 2 in the exhaust flow and collects the plurality of connection ports 2.

[0011] In this embodiment, an in-line four-cylinder internal combustion engine E in which four cylinders from the first cylinder #1 to the fourth cylinder #4 (see FIG. 7) are arranged in line will be described as an example. Therefore, a cooling structure 1 of an exhaust collector pipe M having four connection ports 2 and four exhaust ports 8 will be described. For this reason, the connection port 2 has a first connection port 2a connected to a first exhaust port 8a (see FIG. 7) provided at both ends of the longitudinal direction L of the cylinder head 6, and a second connection port 2b connected to a second exhaust port 8b (see FIG. 7) provided between the first exhaust ports 8a. Note that the exhaust collector pipe M of this embodiment is an equal-length exhaust collector pipe M in which the lengths of the two first connection ports 2a and the two second connection ports 2b are equal. For this reason, the two second connection ports 2b are curved upward in the vertical direction U and then connected to the collector portion 4. However, the exhaust collector pipe M is not limited to such a shape.

[0012] 1 and 2, the cooling structure 1 of the exhaust manifold M includes a cooling passage 10. The cooling passage 10 has an upstream wall 16, a downstream wall 18, a first partition wall 20, a second partition wall 22, a dividing wall 24, a communication passage 26, a cooling water inlet 28, and a cooling water outlet 30.

[0013] The cooling passage 10 covers the connection port 2 and the collecting portion 4, and cools the exhaust gas flowing into the exhaust collecting pipe M. In the high-load, high-speed operating range of the internal combustion engine E, the heat of vaporization of fuel is used to cool the exhaust gas. When cooling the exhaust gas with such fuel, there is a risk that a large amount of fuel components will be contained in the exhaust gas, which deteriorates the exhaust quality. For this reason, by cooling the exhaust collecting pipe M with the cooling passage 10, it is possible to suppress such cooling by the fuel and to suppress deterioration of the exhaust quality.

[0014] 3 and 4, in this embodiment, the cooling passage 10 has an outer wall 31 provided along the outer periphery of the exhaust manifold M. A space is provided between the outer wall 31 and the outer periphery of the exhaust manifold M. Cooling water flows in this space to form the cooling passage 10. The outer wall 31 is made of sheet metal or cast metal.

[0015] 2, 3, and 4, the cooling passage 10 has a first cooling passage 10a covering an upper part of the exhaust manifold M, and a second cooling passage 10b covering a lower part of the exhaust manifold M. In this embodiment, the cooling passage 10 is divided into upper and lower parts by a dividing wall 24, and the upper side of the dividing wall 24 is the first cooling passage 10a, and the lower side is the second cooling passage 10b.

[0016] In this embodiment, the volume of the first cooling passage 10a is larger than the volume of the second cooling passage 10b. More specifically, as shown in FIG. 2, the volume below the collecting portion 4 of the exhaust collecting pipe M is larger than the volume above the collecting portion 4 of the exhaust collecting pipe M. Details will be described later. In the internal combustion engine E, heat tends to build up below the exhaust collecting pipe M. In this embodiment, the second cooling passage 10b is provided below the exhaust collecting pipe M. Since the volume of the second cooling passage 10b is larger than the first cooling passage 10a, the lower portion of the exhaust collecting pipe M is more easily cooled than the upper portion.

[0017] 2, 5, and 6, the upstream wall 16 is a wall provided at the end of the cooling passage 10 on the cylinder head side, and extends in a direction intersecting with the first partition wall 20. As shown in Fig. 2, in this embodiment, the exhaust collector pipe M is provided with a flange 32 for fixing the exhaust collector pipe M to the cylinder head 6. The upstream wall 16 is the surface of the flange 32 on the collector portion 4 side (the exhaust collector pipe M side).

[0018] The downstream wall 18 is a wall provided at the end of the cooling passage 10 on the junction 4 side and extending in a direction intersecting with the first partition wall 20. As shown in Fig. 5 and Fig. 6, in this embodiment, the downstream wall 18 is an inner circumferential surface of an outer wall 31 provided at the end of the cooling passage 10 on the junction 4 side in the short side direction S.

[0019] As shown in FIG. 1, the first partition wall 20 extends along the connection port 2 and separates the cooling passage 10 in the longitudinal direction L of the cylinder head. As shown in FIG. 3 and FIG. 4, in this embodiment, a rib provided on the exhaust collector pipe M extends to the outer wall 31 to form the first partition wall 20. As shown in FIG. 5 and FIG. 6, the first partition wall 20 is provided along the second connection port 2b (see FIG. 1) and extends in the lateral direction S at the center of the longitudinal direction L of the second connection port 2b. In this embodiment, the first partition wall 20 is provided along two second connection ports 2b (see FIG. 1) provided on the inside among the four connection ports 2. That is, in this embodiment, the first partition wall 20 is provided in the second connection port 2b connected to the second cylinder #2 (see FIG. 7) and the third cylinder #3 (see FIG. 7).

[0020] As shown in FIG. 3, FIG. 5, and FIG. 6, the first partition 20 is provided with a gap between it and the upstream wall 16 and is connected to the downstream wall 18. The angle γ between the downstream wall 18 and the first partition 20 is preferably 90 degrees or more. This allows the cooling water to flow smoothly. In this embodiment, the first partition 20 extends to the dividing wall 24 after connecting to the downstream wall 18. By providing the first partition 20 in this manner, the cooling water that has entered from the cooling water inlet 28 flows in one direction along the longitudinal direction L to the cooling water outlet 30 as shown by the arrows in FIG. 5 and FIG. 6. In this embodiment, the two first partitions 20 provided in the second connection port 2b connected to the second cylinder #2 (see FIG. 7) and the third cylinder #3 (see FIG. 7) are shaped symmetrically with respect to the center line of the longitudinal direction L. However, the two first partitions 20 may be shaped asymmetrically.

[0021] The first cooling passage 10a and the second cooling passage 10b each have a first partition 20, an upstream wall 16, and a downstream wall 18.

[0022] An end portion of the first partition wall 20 on the side of the junction 4 is bent from a direction along the connection port 2 toward the longitudinal direction L of the cylinder head 6. As shown in Fig. 5, an end portion 20a of the first partition wall 20 of the first cooling passage 10a on the side of the junction 4 is bent in a first direction from a direction along the connection port 2 toward the outside in the longitudinal direction of the cylinder head 6 (the side surface in the lateral direction S of the cylinder head 6). In this embodiment, the two first partition walls 20 of the first cooling passage 10a provided in the two second connection ports 2b are bent in directions away from each other at the end portions 20a.

[0023] 6, the end portions 20b of the first partition walls 20 of the second cooling passages 10b on the confluence portion 4 side are bent in a second direction from the direction along the connection port 2 toward the longitudinal direction L of the cylinder head 6. In this embodiment, the two first partition walls 20 of the second cooling passages 10b provided in the two second connection ports 2b are bent in directions away from each other at the end portions 20b.

[0024] As shown in Figs. 5 and 6, the first direction is a direction that is bent more toward the outside in the longitudinal direction L of the cylinder head than the second direction. That is, the first partition wall 20 of the second cooling passage 10b is bent more than the first partition wall 20 of the first cooling passage 10a. Specifically, the distance Db shown in Fig. 6 is greater than the distance Da shown in Fig. 5. The distances Da and Db are distances between the intersections of the dividing wall 24 and the first partition wall 20. In addition, the angle β (see Fig. 6) between the center line of the second connection port 2b in the longitudinal direction L and the first partition wall 20 in the second cooling passage 10b is greater than the angle α (see Fig. 5) between the center line of the second connection port 2b in the longitudinal direction L and the first partition wall 20 in the first cooling passage 10a. Furthermore, as shown in Fig. 2, the second cooling passage 10b is formed to bulge downward at the position of the collecting portion 4. As a result, the volume of the second cooling passage 10b in the lower part of the collecting portion 4 becomes larger than the volume of the first cooling passage 10a in the upper part of the collecting portion 4.

[0025] The second partition 22 is provided at a position overlapping with the collecting portion 4, and separates the cooling passages 10 in the longitudinal direction L of the cylinder head 6. In this embodiment, a rib provided on the exhaust collecting pipe M extends to the outer wall 31 to form the second partition 22. The second partition 22 is provided with a gap between it and the downstream wall 18.

[0026] As shown in Figures 1 to 4, the partition wall 24 is provided at the boundary between the first cooling passage 10a and the second cooling passage 10b. As shown in Figures 5 and 6, the partition wall 24 extends along the shapes of the connection port 2 and the collecting portion 4, and divides the cooling passage 10 into upper and lower portions. As shown in Figures 3 and 4, the partition wall 24 extends from approximately the center in the vertical direction of the outer circumferential surface of the connection port 2 toward the outer wall 31. The partition wall 24 around the first connection port 2a is provided with a gap between it and the upstream wall 16. This gap forms a communication passage 26.

[0027] As shown in Fig. 2, the communication passage 26 connects the first cooling passage 10a and the second cooling passage 10b. As shown in Fig. 5 and Fig. 6, the communication passage 26 is provided at both ends of the cooling passage 10 in the longitudinal direction L of the cylinder head 6. In this embodiment, the communication passage 26 is formed along the surface of the upstream wall 16 of the cooling passage 10 on the collecting section 4 side, which is formed along the first connection port 2a.

[0028] The cooling water inlet 28 takes in cooling water into the cooling passage 10. As shown in FIG. 3, the cooling water inlet 28 is provided in the second cooling passage 10b. In this embodiment, the cooling water inlet 28 is a nipple extending downward from the second cooling passage 10b. As shown in FIG. 6, the cooling water inlet is provided in a lower portion on one side in the longitudinal direction L of the cylinder head 6. In this embodiment, the cooling water inlet 28 is provided on the first cylinder #4 side of the cylinder head 6.

[0029] The cooling water outlet 30 drains the cooling water from the cooling passage 10. As shown in FIG. 3, the cooling water outlet 30 is provided in the first cooling passage 10a. The cooling water outlet 30 is provided at the highest position in the vertical direction of the first cooling passage 10a or at a position approximately equal to the highest position. In this manner, the cooling water outlet 30 is provided at the upper part of the cooling passage 10, so that air bubbles in the cooling passage 10 are smoothly discharged. In this embodiment, the cooling water outlet 30 is a nipple extending upward from the first cooling passage 10a. As shown in FIG. 5, the cooling water outlet 30 is provided on the other side of the longitudinal direction L of the cylinder head 6. In addition, the positional relationship between the cooling water inlet 28 and the cooling water outlet 30, which are provided at a relatively low position in the vertical direction, also promotes the discharge of air bubbles. In this embodiment, the cooling water outlet 30 is provided on the first cylinder #1 side of the cylinder head 6.

[0030] As shown in FIG. 5 and FIG. 6, in the cooling structure of the exhaust manifold M configured as above, the cooling water enters from the cooling water inlet 28 and enters the second cooling passage 10b. The cooling water that entered the second cooling passage 10b enters the first cooling passage 10a via the communication passage 26. The cooling water that entered the first cooling passage 10a and the second cooling passage 10b each flows through the first connection port 2a of the fourth cylinder #4 (see FIG. 7) toward the manifold 4. The cooling water turns back at the manifold 4 and flows toward the upstream wall 16 along the first partition 20 of the second connection port 2b of the third cylinder #3 (see FIG. 1). The cooling water turns back at the gap between the first partition 20 and the upstream wall 16 and flows along the first partition 20 toward the manifold 4.

[0031] The cooling water turns back in the gap between the second partition 22 and the downstream wall 18, and flows along the first partition 20 of the second connection port 2b (see FIG. 1 ) of the second cylinder #2 toward the upstream wall 16. The cooling water turns back in the gap between the first partition 20 and the upstream wall 16, and flows along the first partition 20 toward the collecting section 4. The cooling water turns back at the collecting section 4, flows along the first cylinder #1, and is discharged to the cooling water outlet 30. At this time, the cooling water in the second cooling passage 10b passes through the communication passage 26 and is discharged to the cooling water outlet 30.

[0032] Thus, in the cooling structure 1 of the exhaust manifold M of the present disclosure, the cooling water flows in one direction from one side (the fourth cylinder #4 side in this embodiment) to the other side (the first cylinder #1 side in this embodiment) along the longitudinal direction L of the cylinder head 6 while reciprocating in the short direction S along the connection port 2. This makes it easier for the cooling water to flow uniformly.

[0033] Next, the cooling circuit 40 of the internal combustion engine E will be described with reference to FIG.

[0034] The cooling circuit 40 includes a cylinder head cooling passage 6a, a water pump WP, a first cooling path 42, a second cooling path 44, a heat exchanger passage Ht, a radiator Rd, a radiator path 46, an exhaust recirculation cooling passage EGRC, an on-off valve Tms, a bypass path 48, a throttle hot water passage ThB, and a throttle path 50.

[0035] The cylinder head cooling passage 6a is provided inside the cylinder head 6. The cylinder head cooling passage 6a passes near the exhaust port 8 (see FIG. 2 ) to cool the exhaust gas flowing through the exhaust port 8 and to cool the entire cylinder head 6.

[0036] The cylinder head cooling passage 6a flows from the other side (the first cylinder #1 side in this embodiment) to one side (the fourth cylinder #4 side in this embodiment). That is, the cooling water flowing through the cylinder head cooling passage 6a flows in the opposite direction to the cooling water flowing through the cooling passage 10 from one side to the other side. The temperature of the cooling water in the cylinder head cooling passage 6a is low in the first cylinder #1 and increases toward the fourth cylinder #4. The temperature of the cooling water in the cooling passage 10 is low in the fourth cylinder #4 and increases toward the first cylinder #1. Therefore, the cooling water in the cooling passage 10 and the cooling water in the cylinder head cooling passage 6a flow in the opposite directions, which can reduce the variation in exhaust cooling for each cylinder. This makes it easier to suppress the deterioration of exhaust.

[0037] The water pump WP is a pump for circulating the cooling water in the cooling circuit 40. In this embodiment, it is an electric water pump that drives a motor equipped with an impeller by a battery (not shown). The electric water pump can arbitrarily control the flow rate of the cooling water regardless of the operating range of the internal combustion engine E. This makes it easy to adjust the cooling performance of the cooling circuit 40.

[0038] The first cooling path 42 is a path that supplies cooling water to the cylinder head cooling path 6a. The first cooling path 42 is a path that runs from the water pump WP, passes through the cylinder head cooling path 6a, and returns to the on-off valve Tms.

[0039] The second cooling path 44 is a path that supplies cooling water to the cooling passage 10. In this embodiment, the second cooling path 44 is a path that is connected to the cooling water inlet 28 (see FIG. 3) on the No. 4 cylinder #4 side, passes through the cooling passage 10, and returns to the on-off valve Tms from the cooling water outlet 30 on the No. 1 cylinder #1 side.

[0040] The first cooling path 42 and the second cooling path 44 are independent paths from the water pump WP to the on-off valve Tms. As a result, the cooling water cooled by the radiator Rd is supplied to each of the first cooling path 42 and the second cooling path 44 via the water pump WP. As a result, the exhaust manifold M (see FIG. 1) and the cylinder head 6 can be cooled to lower temperatures. Furthermore, since there is no need to supply cooling water from the cylinder head cooling path 6a to the cooling path 10, there is no need to provide a path in the cylinder head 6 for supplying cooling water to the cooling path 10.

[0041] The heat exchanger passage Ht is a passage for supplying the coolant to a heat exchanger that uses the heat of the coolant. In this embodiment, the heat exchanger passage Ht is a passage for supplying the coolant to a heat exchanger (not shown, for example, a heater core) of a heater (not shown) that functions as a heater using the coolant.

[0042] The heat exchanger passage Ht is provided downstream of the cooling passage 10 of the second cooling path 44. Such a heat exchanger may pass the cooling water through a labyrinth structure. As a result, the water pressure of the cooling water is likely to decrease. Therefore, by providing the heat exchanger passage Ht downstream of the cooling passage 10, the decrease in pressure of the cooling water flowing through the cooling passage 10 can be suppressed. Furthermore, the cooling water in the cooling passage 10 always receives heat from the exhaust gas while the internal combustion engine E is operating. Therefore, the cooling water flowing through the heat exchanger passage Ht provided downstream of the cooling passage 10 is in a state where it is warmed by the cooling passage 10. As a result, the heater functions easily, and the time until heating is completed can be shortened. That is, the heater performance is improved.

[0043] The radiator Rd cools the cooling water flowing through the cooling circuit 40. The radiator path 46 branches off from the first cooling path 42 downstream of the cylinder head cooling passage 6a, passes through the radiator Rd, and returns to the on-off valve Tms.

[0044] The exhaust recirculation cooling passage EGRC is a passage for cooling an exhaust recirculation device that circulates the exhaust gas flowing through the exhaust port 8 (see FIG. 1). The exhaust recirculation cooling passage EGRC is connected to the second cooling path 44 upstream of the cooling passage 10. In the high-load, high-speed operating region, the exhaust recirculation device is often not used. For this reason, in the high-load, high-speed operating region, the cooling water flows into the cooling passage 10 without receiving heat from the exhaust recirculation cooling passage EGRC. As a result, even if the exhaust recirculation cooling passage EGRC is provided upstream of the cooling passage 10, the cooling effect of the cooling passage 10 for the exhaust gas is not impaired, and the cooling circuit 40 does not become complicated.

[0045] The on-off valve Tms is a valve that takes in the cooling water from the radiator path 46 when the cooling water reaches a predetermined temperature, and allows the cooling water to flow into the radiator path 46. The on-off valve Tms is, for example, a thermostat that opens in response to the temperature of the cooling water. The downstream of the on-off valve Tms is connected to the water pump WP. Therefore, while the water pump WP is operating and before the on-off valve Tms opens, the cooling water flows only through the first cooling path 42 and the second cooling path 44, and the temperature of the cooling water rises.

[0046] The bypass path 48 is a path that branches off from the cooling path 10 and the downstream of the heat exchanger path Ht, and connects to the downstream of the on-off valve Tms and the upstream of the downstream of the water pump WP. When the internal combustion engine E is started and warmed up, the coolant heated by the cooling path 10 flows through the bypass path 48, thereby shortening the warm-up time of the internal combustion engine E. This makes it possible to suppress deterioration of exhaust gas when the internal combustion engine E is started.

[0047] The throttle hot water passage ThB is a passage for preventing freezing of a throttle valve that adjusts the amount of intake air of the internal combustion engine E. The throttle passage 50 is a passage that branches off from the first cooling passage 42 downstream of the cylinder head cooling passage 6a, passes through the throttle hot water passage ThB, and returns to the first cooling passage 42.

[0048] As described above, according to the cooling circuit 40 of the internal combustion engine E of the present disclosure, the cooling water flowing through the cooling passage 10 and the cooling water flowing through the cylinder head cooling passage 6a can flow independently. This makes it easier to cool the exhaust gas flowing through the exhaust manifold M.

[0049] <Other embodiments> Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0050] (a) In the above embodiment, the internal combustion engine E in which the first cylinder #1 to the fourth cylinder #4 are arranged in series has been described as an example, but the present disclosure is not limited thereto. The internal combustion engine E may be, for example, a three-cylinder in-line type, or a V-type or horizontally opposed type with six or more cylinders. In this case, the first partition 20 may be provided along the connection port 2 connected to the middle cylinder.

[0051] (b) The cooling circuit 40 in the above embodiment is just an example, and a cooling path of the device used in the above embodiment may be added to the cooling circuit 40. For example, in the case where a turbocharger is used in the internal combustion engine E, a path for cooling the turbocharger may be added to the first cooling path 42 or the second cooling path 44. [Explanation of symbols]

[0052] 1: cooling structure, 2: connection port, 2a: first connection port, 2b: second connection port 4: Collector, 6: Cylinder head, 6a: Cylinder head cooling passage 8: exhaust port, 8a: first exhaust port, 8b: second exhaust port 10: Cooling passage, 10a: First cooling passage, 10b: Second cooling passage 16: Upstream wall, 18: Downstream wall 20: First partition wall, 22: Second partition wall, 24: Dividing wall 26: Communication path, 28: Cooling water inlet, 30: Cooling water outlet 40: Cooling circuit 42: First cooling path, 44: Second cooling path 46: Radiator route, 48: Bypass route Rd: Radiator, Tms: On-off valve, WP: Water pump E: Internal combustion engine, Ht: Heat exchanger passage, EGRC: Exhaust gas recirculation cooling passage L: Longitudinal direction, S: Shortitudinal direction M: Exhaust manifold

Claims

1. A cooling structure for an exhaust manifold having a plurality of exhaust ports provided in a cylinder head extending in a longitudinal direction, a plurality of connection ports connected to the plurality of exhaust ports, and a collecting section provided downstream of the connection ports in an exhaust flow direction and collecting the plurality of connection ports, a cooling passage covering the connection port and the collection portion; the cooling passage includes a first cooling passage covering an upper portion of the exhaust manifold, a second cooling passage covering a lower portion of the exhaust manifold, and a dividing wall provided at a boundary between the first cooling passage and the second cooling passage, The volume of the first cooling passage is larger than the volume of the second cooling passage. Cooling structure for exhaust manifold.

2. the cooling passage includes a communication passage that connects the first cooling passage and the second cooling passage, The communication passage is provided at an end of the cooling passage in the longitudinal direction. The cooling structure of the exhaust manifold according to claim 1 .

3. The cooling passage has an upstream wall provided at an end of the cooling passage on the cylinder head side and extending in the longitudinal direction, The partition wall is provided with a gap between it and the upstream wall. The cooling structure of the exhaust manifold according to claim 1 .

4. The cooling passage has a cooling water inlet for taking in cooling water into the cooling passage and a cooling water outlet for discharging the cooling water from the cooling passage, The cooling water inlet is provided at one end of the cooling passage in the longitudinal direction, the cooling water outlet is provided at the other end of the cooling passage in the longitudinal direction, The cooling water in the cooling passage flows from the one side to the other side. The cooling structure of the exhaust manifold according to claim 1 .

5. The cylinder head has a cylinder head cooling passage through which the cooling water flows from the other side to the one side. The cooling structure of an exhaust manifold according to claim 4.

6. The cooling passage has a cooling water inlet for taking in cooling water into the cooling passage and a cooling water outlet for discharging the cooling water from the cooling passage, The cooling water inlet is provided in the second cooling passage, The cooling water outlet is provided in the first cooling passage. The cooling structure of the exhaust manifold according to claim 1 .

7. The cooling passage includes a partition wall extending from the dividing wall along the connection port and separating the cooling passages in the longitudinal direction. The cooling structure for an exhaust manifold according to any one of claims 1 to 6.

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