Drainage structure of exhaust ports

Abstract

To prevent condensed water occurring in exhaust ports from flowing out to the downstream side and spilling over other components.SOLUTION: The invention relates to a drainage structure of exhaust ports in an internal combustion engine including: a plurality of combustion chambers 20 which are arranged at intervals in a cylinder row direction between a cylinder block 11 and a cylinder head 12; a plurality of exhaust ports 23a, 23b which are formed communicating with the respective combustion chambers 20; an exhaust collection part 27 which is integrally formed with the cylinder head 12 and where the exhaust ports 23a, 23b gather; and water jackets 31 to 34 through which a coolant for cooling the exhaust ports 23a, 23b pass. Grooves 41a, 41b, 42 which can capture condensed water by capillary force are formed on wall surfaces of the exhaust ports 23a, 23b.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a drainage structure for an exhaust port. [Background technology]

[0002] An engine cylinder head is provided with an exhaust port for discharging exhaust gas from the combustion chamber to an exhaust pipe. Patent Document 1 discloses a configuration in which an exhaust manifold is integrated with the cylinder head, and the exhaust ports are collected at an exhaust collection section inside the cylinder head. In addition, an exhaust pipe equipped with a catalytic converter or the like is connected downstream of the exhaust collection section.

[0003] As in the cylinder head disclosed in Patent Document 1, by configuring the exhaust ports to gather at an exhaust gathering section inside the cylinder head, it is possible to make the exhaust manifold smaller, and it has the advantage of being able to bring the catalytic converter closer to the combustion chamber, enabling the catalytic converter to warm up more quickly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-139421 A Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, when the engine is started cold, condensation may occur when the temperature of the exhaust port wall drops. The condensed water flows together with the exhaust gas and flows out to the downstream side of the exhaust port. If the condensed water that flows out from the downstream side of the exhaust port comes into contact with the catalyst or sensors such as the air-fuel ratio sensor arranged in the exhaust pipe, it may damage them. In particular, when the engine is started cold, the heat capacity of the adjacent cylinder block is large and a water jacket is arranged around the exhaust port, so the temperature rise in the exhaust port is slow and the condensed water that is generated is difficult to evaporate and is therefore likely to flow out to the downstream side of the exhaust port.

[0006] The present invention has been made in consideration of the problems described above, and aims to prevent condensed water generated in the exhaust port from flowing downstream and causing other components to become wet. [Means for solving the problem]

[0007] The present invention provides a drainage structure for an exhaust port in an internal combustion engine comprising a plurality of combustion chambers arranged at intervals in the cylinder row direction between a cylinder block and a cylinder head, a plurality of exhaust ports formed in communication with each of the plurality of combustion chambers, an exhaust collection section formed integrally with the cylinder head and in which the plurality of exhaust ports are collected, and a water jacket through which cooling water passes to cool the plurality of exhaust ports, wherein a groove capable of collecting condensed water by capillary force is formed on a wall surface of the exhaust port. Effect of the Invention

[0008] According to the present invention, condensed water generated in the exhaust port can be prevented from flowing downstream and becoming wet on other components. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a rear perspective view of the engine as seen diagonally from the left side. [Diagram 2] FIG. 1 is a view of the engine from the left side. [Diagram 3]FIG. 2 is a cross-sectional view showing a configuration of a cylinder head. [Figure 4] FIG. 2 is a cross-sectional view showing a configuration of a cylinder head. [Diagram 5] FIG. 2 is a cross-sectional view showing the configuration of a cylinder block and a cylinder head. [Figure 6] FIG. 2 is a rear perspective view of the cylinder head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The drainage structure of the exhaust port according to the embodiment of the present invention is an exhaust drainage structure for an internal combustion engine including a plurality of combustion chambers 20 arranged at intervals between a cylinder block 11 and a cylinder head 12 in the cylinder row direction, a plurality of exhaust ports 23a, 23b formed in communication with the plurality of combustion chambers 20, an exhaust collection section 27 formed integrally with the cylinder head 12 and in which the plurality of exhaust ports 23a, 23b are collected, and water jackets 31 to 34 through which cooling water for cooling the plurality of exhaust ports 23a, 23b passes. Grooves 41a, 41b, 42 capable of collecting condensed water by capillary force are formed on the wall surfaces of the exhaust ports 23a, 23b. Therefore, it is possible to prevent the condensed water generated in the exhaust ports 23a, 23b from flowing out to the downstream side of the exhaust ports 23a, 23b by the exhaust gas flow, and therefore it is possible to prevent other components such as a catalyst carrier and sensors arranged in the exhaust passage from becoming wet. EXAMPLES

[0011] Hereinafter, a vehicle engine 100 as an internal combustion engine according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the engine 100 as seen from the left rear. FIG. 2 is a view of the engine 100 as seen from the left, omitting the chain cover 17 described later. In each of the figures including the following figures, the chain cover 17 side along the direction of the crankshaft Cr is indicated as the left side by an arrow "left", and the opposite side is indicated as the right side. In addition, the upper side approximately along the cylinder axis Cl is indicated as an arrow "up", and the opposite side is indicated as the lower side. In addition, the intake side of the direction approximately perpendicular to the cylinder axis Cl and the crankshaft Cr is indicated as the front side by an arrow "front", and the exhaust side, which is the opposite side, is indicated as the rear side. The arrangement direction of the engine 100 is not limited to the illustrated example, and can be appropriately selected according to the vehicle model, etc.

[0012] The engine 100 is suspended on a vehicle body frame (not shown) via a plurality of engine mounts, and is integrally connected to and supported by the vehicle body frame, and is mounted in an engine compartment of the vehicle. The engine 100 of this embodiment is a multi-cylinder engine, specifically a three-cylinder DOHC gasoline engine or the like. The engine 100 has an engine body 10. The engine body 10 is configured by integrally joining a cylinder head 12 and a cylinder head cover 13 to the upper part of a cylinder block 11. A crank chamber is formed inside the cylinder block 11. A crankshaft 14 is supported in the crank chamber so as to be rotatable around the crankshaft Cr. In addition, the cylinder block 11 has each cylinder arranged in series in the left-right direction, and each cylinder axis Cl is oriented approximately in the up-down direction. As shown in FIG. 5 described later, a piston 16 is fitted in a cylinder bore 15 of each cylinder of the cylinder block 11, and the piston 16 reciprocates along the cylinder axis Cl in the cylinder bore 15 to rotate the crankshaft 14. In addition, an oil pan 18 for storing engine oil is integrally joined to the lower part of the cylinder block 11.

[0013] As shown in Fig. 1, a chain cover 17 that protects the timing chain is attached to the left side of the engine body 10. The chain cover 17 is fixed to the cylinder block 11 and the cylinder head 12 using fastening bolts while covering the left side surfaces of the cylinder block 11 and the cylinder head 12. The chain cover is omitted in Fig. 2.

[0014] The engine 100 also has intake system parts that draw in air from the outside and supply clean air (intake air) to the combustion chamber 20, fuel system parts that supply fuel, and exhaust system parts that exhaust exhaust gas after combustion from the engine 100. The engine 100 also has valve system parts that drive and control the intake valve and exhaust valve.

[0015] Figures 3 and 4 are cross-sectional views showing the configuration of the cylinder head 12. Figure 3 is a cross-sectional view taken along line II in Figure 2, and Figure 4 is a cross-sectional view taken along line II-II in Figure 2. Figure 5 is a cross-sectional view showing the configuration of the cylinder block 11 and the cylinder head 12. Note that Figure 5 is a cross-sectional view taken along line III-III in Figures 3 and 4, and shows the configuration of the central cylinder out of the three cylinders. Figure 6 is a perspective view of the cylinder head 12 shown in Figure 5, seen from the rear.

[0016] As shown in Figure 5, a combustion chamber 20 is formed between the cylinder block 11 and the cylinder head 12 by joining the cylinder block 11 and the cylinder head 12. An ignition plug is disposed in the cylinder head 12 so that its tip is positioned within the combustion chamber 20. The air-fuel mixture in the combustion chamber 20 is ignited by the spark plug and combusted, causing the piston 16 to reciprocate within the cylinder bore 15.

[0017] As shown in FIG. 3 and FIG. 5, intake ports 21a, 21b communicating with the combustion chamber 20 are formed on the front side of the cylinder head 12. The intake ports 21a, 21b extend from the combustion chamber 20 toward the front side wall surface of the cylinder head 12 diagonally upward toward the front. In this embodiment, two (a pair) of intake ports 21a, 21b separated in the left-right direction are formed for one cylinder. An intake valve is disposed in each of the intake ports 21a, 21b, and the mixture is taken into the combustion chamber 20 by opening the intake valve. The intake ports 21a, 21b have an opening 22 formed in the front side wall surface of the cylinder head 12 opposite the combustion chamber 20 side, and an intake passage formed of an intake pipe or the like is connected to the intake passage. A throttle body equipped with a throttle valve is connected to the intake passage. The flow rate of the intake air taken into the combustion chamber 20 is controlled by opening and closing the throttle valve according to the accelerator opening. A fuel injector is attached downstream of the throttle valve, and fuel pumped from a fuel tank is injected from the fuel injector into intake ports 21a, 21b.

[0018] Meanwhile, exhaust ports 23a, 23b communicating with the combustion chamber 20 are formed on the rear side of the cylinder head 12. The exhaust ports 23a, 23b extend from the combustion chamber 20 toward the rear side wall surface of the cylinder head 12, diagonally upward toward the rear. In this embodiment, two (a pair) exhaust ports 23a, 23b separated in the left-right direction are formed for one cylinder. An exhaust valve is disposed in each of the exhaust ports 23a, 23b, and exhaust gas is discharged from the combustion chamber 20 by opening the valve. 3, the two exhaust ports 23a, 23b are partitioned by a port partition portion 24. The two exhaust ports 23a, 23b join together downstream, more specifically, downstream of the rear end of the port partition portion 24.

[0019] The flow path where the two exhaust ports 23a, 23b join together is called the junction 25. Here, the junction in the left cylinder is called junction 25A, the junction in the center cylinder is called junction 25B, and the junction in the right cylinder is called junction 25C. The junctions 25A and 25B incline to the right as they approach the downstream side. On the other hand, the junction 25C inclines to the left as they approach the downstream side. The junction 25A and the junction 25B are partitioned by the cylinder partition 26A, and the junction 25B and the junction 25C are partitioned by the cylinder partition 26B. The three junctions 25A, 25B, and 25C gather downstream, more specifically, downstream of the rear end of the cylinder partition 26. In other words, the cylinder head 12 of this embodiment is integrated with an exhaust manifold, and the exhaust ports 23a, 23b of the respective cylinders are gathered together inside the cylinder head 12.

[0020] The flow path where the exhaust ports 23a, 23b of the three cylinders are collected via the confluence parts 25A, 25B, 25C is called the exhaust collection part 27. The exhaust collection part 27 has an opening 28 formed on the rear side wall surface of the cylinder head 12 opposite to the combustion chamber 20 side. A flange part 29 is formed on the opening edge of the opening 28 on the rear side wall surface of the cylinder head 12, and an exhaust passage consisting of an exhaust pipe and the like is connected via the flange part 29. As shown in FIG. 1, a catalyst device 30 is connected to the exhaust passage. The catalyst device 30 purifies toxic components contained in the exhaust gas by oxidizing and reducing them. The catalyst device 30 has a cylindrical shape, and a central axis L is approximately aligned along the vertical direction. The catalyst device 30 of this embodiment is arranged close to the cylinder block 11, so that the catalyst carrier can be warmed up early.

[0021] 5, the cylinder block 11 has water jackets 31, 32 arranged to surround each cylinder from the front and rear. The water jacket 31 is arranged in front of the cylinder bore 15, below the intake ports 21a, 21b. The water jacket 32 ​​is arranged in the rear of the cylinder bore 15, below the exhaust ports 23a, 23b. Cooling water flows through the water jackets 31, 32 to cool the areas around the cylinders and the exhaust ports 23a, 23b, which have become hot.

[0022] The cylinder head 12 also has water jackets 33, 34 arranged to surround the exhaust collection portion 27 from above and below. The water jacket 33 is arranged in front of the flange portion 29, above the exhaust collection portion 27. The water jacket 34 is arranged in front of the flange portion 29, below the exhaust collection portion 27. 4, the water jacket 33 is formed long in the left-right direction. The water jacket 33 is arranged so as to overlap the exhaust collecting portion 27 when viewed from above, and also overlap a part of the junction portion (junction portion 25A). The water jacket 34 has the same configuration as the water jacket 33. The exhaust collecting portion 27 and the like that have become hot can be cooled by the flow of cooling water through the water jackets 33 and 34.

[0023] As described above, the cylinder head 12 of this embodiment has an integrated exhaust manifold, and the exhaust ports 23a, 23b of each cylinder are assembled inside the cylinder head 12. In the cylinder head 12 with such an integrated exhaust manifold, the exhaust collection part 27 and the vicinity of the flange part 29, through which the exhaust gas discharged from each exhaust port 23a, 23b always passes, tend to become particularly hot, rather than each individual exhaust port 23a, 23b. Therefore, by arranging water jackets 33, 34 so as to surround the exhaust collection part 27 from above and below, the exhaust collection part 27 can be cooled.

[0024] In the engine 100 configured as above, condensed water may be generated due to a drop in temperature of the wall surfaces of the exhaust ports 23a, 23b during a cold start of the engine 100, etc. The engine 100 of this embodiment is provided with a drainage structure for draining the condensed water generated in the exhaust ports 23a, 23b. Specifically, a groove portion 40 capable of collecting the condensed water by capillary force is formed on the wall surfaces of the exhaust ports 23a, 23b.

[0025] The configuration of the groove portion 40 will be specifically described below. The groove portion 40 has a plurality of grooves 41a, 41b extending along the flow path of the exhaust gas, and a plurality of grooves 42 at least a portion of which extends in a direction intersecting the flow path of the exhaust gas. The grooves 41a, 41b, 42 are fine grooves that can collect condensed water by capillary force (capillary phenomenon). The grooves 41a, 41b, 42 each have a substantially V-shaped cross section with a groove width that decreases toward the bottom of the groove, and the groove width is 1 mm or less. For ease of understanding, the spacing between adjacent grooves 41a, 41b, 42 and the groove width are shown as being large in each drawing.

[0026] As shown in FIG. 3, a plurality of grooves 41a extending along the flow path are formed on the lower surface (lower wall) of each exhaust port 23a, 23b as a wall surface. One end of the groove 41a in the extending direction is located on the combustion chamber 20 side of the exhaust port 23a, 23b, and the other end reaches the vicinity of the flange portion 29, here, to the opening 28 of the exhaust collecting portion 27. That is, the groove 41a is continuously formed from the combustion chamber 20 side of the exhaust port 23a, 23b through the merging portions 25A, 25B, 25C to the opening 28 of the exhaust collecting portion 27. In addition, some of the plurality of grooves 41a can be formed by merging adjacent grooves 41a at the merging portions 25A, 25B, 25C (or the exhaust collecting portion 27). Similarly, a plurality of grooves 41a extending along the flow path are formed on the upper surface (upper wall) of each exhaust port 23a, 23b as a wall surface. Even when line II in Figure 5 is viewed from the opposite side to the direction of the arrow, as in Figure 3, groove 41a is formed continuously from the combustion chamber 20 side of exhaust ports 23a, 23b, via confluences 25A, 25B, 25C, to the opening 28 of the exhaust collection section 27.

[0027] On the other hand, as shown in FIG. 5 and FIG. 6, a plurality of grooves 42 extending in a direction intersecting the flow passage are formed on the side surface (inner side surface) as the wall surface of each exhaust port 23a, 23b, more specifically, the port partition wall portion 24 and the cylinder partition wall portion 26A, 26B. Specifically, the main portion of each groove 42 is formed so that the direction of extension is along the vertical direction. In each groove 42 of this embodiment, one end in the direction of extension is located on the upper wall side, and the other end is located on the lower wall side. Note that, in some of the plurality of grooves 42, the lower wall side and the upper wall side merge with groove 41a (or groove 41b described later) extending along the flow passage. However, all the grooves 42 may be formed so as to merge with groove 41a (and groove 41b).

[0028] Among the side surfaces of the exhaust ports, the side surface serving as the wall surface of exhaust port 23a (the exhaust port located on the leftmost side) in the left cylinder and the side surface serving as the wall surface of exhaust port 23b (the exhaust port located on the rightmost side) in the right cylinder have a plurality of grooves 41b extending along the flow path. One end of groove 41b in the extending direction is located on the combustion chamber 20 side of exhaust ports 23a, 23b, and the other end reaches the vicinity of flange portion 29, here, to opening 28 of exhaust collection portion 27. That is, groove 41b is formed continuously from the combustion chamber 20 side of exhaust ports 23a, 23b through junction portions 25A, 25C to opening 28 of exhaust collection portion 27. Figures 5 and 6 show a plurality of grooves 41b formed up to the vicinity of exhaust collection portion 27 in the exhaust port of the right cylinder.

[0029] Here, the groove portion 40 (grooves 41a, 41b, 42) can be formed by inserting a core provided with protrusions for forming the groove portion 40 into the space that will become the cylinder head 12. Alternatively, the groove portion 40 (grooves 41a, 41b, 42) can be formed by masking the inner surface other than the grooves 41a, 41b, 42, and then dissolving (etching) only the grooves 41a, 41b, 42 using an alkaline solution or the like.

[0030] Next, the function and effect of the groove portion 40 configured as described above will be described. If condensed water occurs on the wall surface of the exhaust ports 23a, 23b, the condensed water is collected by the capillary force of the groove portion 40 (grooves 41a, 41b, 42). This makes it possible to prevent the condensed water generated in the exhaust ports 23a, 23b from flowing out to the downstream side of the exhaust ports 23a, 23b due to the exhaust gas flow. This makes it possible to prevent other parts, such as the catalyst carrier and sensors, arranged in the exhaust passage from becoming wet.

[0031] Furthermore, because one end of grooves 41a, 41b is formed up to the vicinity of flange portion 29, the condensed water collected by grooves 41a, 41b can be moved along grooves 41a, 41b to the vicinity of flange portion 29 (see the black arrows in FIG. 6). As described above, the vicinity of flange portion 29, through which exhaust gas constantly passes, is particularly likely to become hot. Therefore, the condensed water that has moved up to the vicinity of flange portion 29 can be evaporated in the vicinity of flange portion 29, which has become hot. This makes it possible to prevent other parts, such as the catalyst carrier and sensors, arranged in the exhaust passage from becoming wet.

[0032] Furthermore, grooves 42 extend in a direction intersecting the flow path of the exhaust gas, and are capable of holding the collected condensed water. At least a portion of grooves 42 merges with grooves 41a and 41b. Therefore, the condensed water collected by grooves 42 can be moved to grooves 41a and 41b (see the black arrows in FIG. 6), and further moved to the vicinity of flange portion 29. The condensed water that has moved to the vicinity of flange portion 29 can be evaporated in the vicinity of flange portion 29, which has become hot.

[0033] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and modifications and the like are possible within the scope of the present invention.

[0034] In the above embodiment, the case of the three-cylinder engine 100 has been described, but the present invention is not limited to this case, and may be an engine with multiple cylinders other than three cylinders, or may be a single cylinder engine. In the above-described embodiment, a case has been described in which two (a pair) exhaust ports 23a, 23b are formed for one cylinder, spaced apart in the left-right direction, but this is not limited to this case, and one exhaust port may be formed for one cylinder. [Explanation of symbols]

[0035] 100: engine 10: engine body 11: cylinder block 12: cylinder head 13: cylinder head cover 20: combustion chamber 23a, 23b: exhaust port 24: port partition wall portion 26A-26C: cylinder partition wall portion 27: exhaust collection portion 29: flange portion 31-34: water jacket 40: groove portion 41a, 41b, 42: groove

Claims

1. a plurality of combustion chambers arranged at intervals in a cylinder row direction between a cylinder block and a cylinder head; A plurality of exhaust ports formed in communication with the plurality of combustion chambers, respectively; an exhaust collection portion formed integrally with the cylinder head and in which the plurality of exhaust ports are collected; A drainage structure for an exhaust port in an internal combustion engine comprising: a water jacket through which cooling water for cooling the plurality of exhaust ports passes, 1. A drainage structure for an exhaust port, comprising: a wall surface of the exhaust port having a groove formed thereon for collecting condensed water by capillary force.

2. The exhaust collecting portion has a flange portion for connecting an exhaust passage, 2. The drainage structure of an exhaust port according to claim 1, wherein an end of the groove is formed adjacent to the flange portion.

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