Cylinder head and internal combustion engine

Abstract

To easily circulate a cooling liquid to a part comparatively far away from a water passing port in which the cooling liquid flows in a water jacket of a cylinder head.SOLUTION: A water jacket 7 has a first water passing port 11 in which a cooling liquid flows, a second water passing port 12 from which the cooling liquid flows out, and a body portion 13 that connects the first water passing port 11 and the second water passing port 12, and in which the cooling liquid flows. The body portion 13 has a first end portion 13a provided with a first water passing port 11, a second end portion 13b on the opposite side to the first end portion 13a, and a third end portion 13c provided with a second water passing port 12. The second end portion 13b is provided with a projecting portion 13e projecting out to the opposite side to the first end portion 13a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cylinder head and an internal combustion engine. [Background technology]

[0002] An internal combustion engine in which a water jacket is formed in a cylinder head is disclosed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-55622 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem with the water jacket is that it is difficult to circulate the coolant from the water pump to a location that is relatively far away from the water inlet through which the coolant flows.

[0005] The present invention has been made in view of the above, and aims to make it easier for coolant to flow to a location in a water jacket of a cylinder head that is relatively far away from the water passage port through which the coolant flows. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the cylinder head of the present invention is a cylinder head formed with a water jacket, wherein the water jacket has a first water passage through which coolant flows in, a second water passage through which the coolant flows out, a first end at which the first water passage is provided, a second end opposite the first end, and a third end separate from the first end and the second end and at which the second water passage is provided, and has a main body portion connecting the first water passage and the second water passage and through which the coolant flows, and wherein the second end is provided with a protrusion protruding opposite to the first end.

[0007] With this configuration, the second end has a convex portion that protrudes on the opposite side from the first end, making it easier for the coolant to flow to the tip of the second end, i.e., the tip of the convex portion, which is a location relatively far from the first water passage, compared to when the second end is flat.

[0008] In the cylinder head, for example, the end of the convex portion on the side of the first end portion has a curved shape whose cross section becomes smaller toward the tip of the convex portion.

[0009] According to this configuration, the flow rate of the coolant can be increased by the throttling effect of the end portion, and therefore a decrease in the flow rate of the coolant from the convex portion to the second water passage port can be suppressed.

[0010] The cylinder head is located on the opposite side of the second end from the first end, and has a mounting surface to which an exhaust manifold is attached, and the protrusion protrudes toward the mounting surface.

[0011] With this configuration, the cooling performance of the water jacket for the mounting surface and the exhaust manifold can be improved.

[0012] In the cylinder head, for example, the exhaust manifold is attached to the mounting surface by a fastener.

[0013] With this configuration, thermal expansion of the fasteners that attach the exhaust manifold to the mounting surface can also be suppressed.

[0014] An internal combustion engine according to the present invention includes the cylinder head.

[0015] With this configuration, the effects of the cylinder head can be achieved. [Effects of the Invention]

[0016] According to the present invention, it is possible to facilitate the flow of coolant to a portion of the water jacket of the cylinder head that is relatively far away from the water passage port through which the coolant flows. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a plan view that schematically shows an internal combustion engine according to an embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing the outer shape of the water jacket according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In this specification, the vertically upward direction is basically defined as the upward direction, and the vertically downward direction is basically defined as the downward direction. In addition, in this specification, components according to the embodiment and their descriptions may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. The components may also be described using expressions different from those in this specification.

[0019] 1 is a schematic plan view of an internal combustion engine 1 according to an embodiment. The internal combustion engine 1 is, for example, a two-cylinder reciprocating engine mounted on a vehicle. Note that the internal combustion engine 1 may be another type of internal combustion engine, or may be mounted on another device.

[0020] As shown in the drawings, for convenience, an X-axis, a Y-axis, and a Z-axis are defined in this specification. The X-axis, the Y-axis, and the Z-axis are perpendicular to one another. The X-axis is set along the width of the internal combustion engine 1. The Y-axis is set along the depth of the internal combustion engine 1. The Z-axis is set along the height of the internal combustion engine 1. In this embodiment, the Z-axis is set along the vertical direction.

[0021] Furthermore, in this specification, the X direction, Y direction, and Z direction are defined. The X direction is a direction along the X axis, and includes the +X direction indicated by the X axis arrow and the -X direction opposite to the X axis arrow. The Y direction is a direction along the Y axis, and includes the +Y direction indicated by the Y axis arrow and the -Y direction opposite to the Y axis arrow. The Z direction is a direction along the Z axis, and includes the +Z direction indicated by the Z axis arrow and the -Z direction opposite to the Z axis arrow. The +Z direction is the upward direction. The -Z direction is the downward direction.

[0022] The internal combustion engine 1 has a cylinder head 2 and a cylinder block 3. Only a portion of the cylinder block 3 is shown in Fig. 1. The cylinder head 2 and the cylinder block 3 may be separate members, or may be molded integrally to form a single block. The top surface of the cylinder block 3 is covered by a head cover or the like.

[0023] The cylinder block 3 has two cylinder bores 3a extending in the vertical direction. The cylinder bores 3a are included in cylinders C. A piston is provided in each cylinder bore 3a so that it can slide vertically. A connecting rod is connected to the piston. When the piston reciprocates within the cylinder bore 3a, this reciprocating motion is converted into rotation of the crankshaft by the connecting rod.

[0024] The cylinder head 2 is provided on top of the cylinder block 3. The cylinder head 2 is provided with combustion chambers included in the cylinders C, each corresponding to a cylinder bore 3a, intake valves that open and close intake ports leading to the combustion chambers, exhaust valves that open and close exhaust ports 4 (see Figure 3) that connect to the combustion chambers and through which exhaust flows, spark plugs, etc. The intake valves and exhaust valves operate in response to the rotation of a camshaft that is linked to the crankshaft. The exhaust port 4 is also referred to as an exhaust flow path.

[0025] The cylinder head 2 has regions 2a to 2e. Regions 2a to 2d are provided for each cylinder C. An intake valve is provided in region 2a. An exhaust valve is provided in region 2b. A spark plug is provided in region 2c.

[0026] The cylinder head 2 also has a mounting surface 2f to which the exhaust manifold 5 is attached. The exhaust manifold 5 is fixed to the cylinder head 2 with fasteners 31 such as bolts. The inside of the exhaust manifold 5 communicates with the outlet 4a of the exhaust port 4 (see Figure 3).

[0027] A water jacket 7 is also formed in the cylinder block 3. Coolant (cooling water) supplied from an electric water pump flows through the water jacket 7. The arrows in Fig. 1 schematically show an example of the flow direction of the coolant.

[0028] FIG. 2 is a perspective view schematically showing the outer shape of the water jacket 7 according to the embodiment. As shown in FIGS. 1 and 2, the water jacket 7 has a first water port 11, a second water port 12, and a main body 13. The first water port 11 is the inlet through which coolant supplied from the water pump flows. That is, the first water port 11 is the inlet. The second water port 12 is the outlet through which coolant flows. The second water port 12 is located in the +Z direction, i.e., above the first water port 11. The main body 13 connects the first water port 11 and the second water port 12, through which coolant flows. The coolant flows from the first water port 11 into the main body 13 and flows out from the second water port 12. This allows the coolant to cool various parts of the cylinder head 2 and the cylinder block 3.

[0029] The main body 13 has a plurality of end portions 13a to 13c. The end portion 13a is the end portion on the +X direction side. The end portion 13b is the end portion opposite the end portion 13a. That is, the end portion 13b is the end portion on the -X direction side. The end portion 13c is the end portion on the +Y direction side. The main body 13 also has an end portion (not shown) opposite the end portion 13c. The end portion opposite the end portion 13c is the end portion on the -Y direction side.

[0030] Figure 3 is a cross-sectional view taken along line III-III in Figure 1. As shown in Figures 1 to 3, a first water passage port 11 is provided at end portion 13a. That is, first water passage port 11 is provided on the opposite side of main body portion 13 from outlet 4a of exhaust port 4. A second water passage port 12 is provided at end portion 13c. That is, second water passage port 12 is provided at end portion 13c, which is different from end portions 13a and 13b.

[0031] Further, the end 13b is provided with a protrusion 13e that protrudes on the opposite side from the end 13a. The protrusion 13e protrudes from the periphery of the protrusion 13e of the end 13b toward the mounting surface 2f. The end 13f of the protrusion 13e on the end 13a side has a curved shape whose cross section becomes smaller toward the tip 13g of the protrusion 13e. That is, the end 13f of the protrusion 13e has a pair of curved portions 13fa. In other words, a recessed shape (concave portion) is formed on both sides of the protrusion 13e in the Y direction.

[0032] The main body 13 is formed so as to surround the regions 2a to 2e of the cylinder head 2 and to sandwich the exhaust port 4 therebetween.

[0033] As shown in FIGS. 1 to 3, the main body 13 has a base flow path 21, an upper flow path 22, and a lower flow path .

[0034] The base flow passage 21 is connected to the first water passage 11 and the second water passage 12. The base flow passage 21 has multiple flow passages facing each of the regions 2a to 2e. For example, when the first water passage 11 is used as the reference, the base flow passage 21 has two flow passages 21a and 21b extending in different directions from the first water passage 11. One flow passage 21a runs from the first water passage 11 through the outer edge of the base flow passage 21 on the +Y direction side of the first water passage 11 to the second water passage 12. The flow passage 21a is provided around one cylinder bore 3a and the combustion chamber (on the +Y direction side). The other flow passage 21b runs from the first water passage 11 through the outer edge of the base flow passage 21 on the -Y direction side of the first water passage 11 to the end of the base flow passage 21 on the -X direction side. The flow passage 21b is provided around the other cylinder bore 3a and the combustion chamber (on the -Y direction side).

[0035] As shown in FIG. 2, each of the two flow paths 21a, 21b has two notches 24 extending upward from the lower surface 21c in the +Z direction. The portion between the two notches 24 in each of the flow paths 21a, 21b is a stagnation space 21d. The stagnation space 21d is also referred to as a region or a portion. The notches 24 are also referred to as a notch, a recess, or a hollow. Each of the two flow paths 21a, 21b has a notch 25 extending downward from the upper surface 21e.

[0036] As shown in FIG. 1 , the main body 13 has a plurality of branch portions 26, 27, and 28, which are locations on a straight line L1 extending from the end 13a toward the end 13b, i.e., in the −X direction, where the main body 13 branches into a plurality of flow paths. The straight line L1 passes through, for example, approximately the center of the main body 13 in the +Y direction. The straight line L1 passes through approximately the center between two cylinders C. Of the plurality of branch portions 26, 27, and 28, at least the branch portion 27 is provided between the two cylinders C. At the branch portions 26, 27, and 28, the flow paths are branched symmetrically with respect to the straight line L1, for example. The branch portions 26, 27, and 28 are also referred to as flow path branch portions.

[0037] Branching unit 26 branches the flow path into three flow paths 26a, 26b, and 26c. Flow path 26a extends in the -X direction, flow path 26b extends in the +Y direction, and flow path 26c extends in the -Y direction. The flow rate of flow path 26b and the flow path 26c are approximately the same. Branching unit 27 branches the flow path into three flow paths 27a, 27b, and 27c. Flow path 27a extends in the -X direction, flow path 27b extends in the +Y direction, and flow path 27c extends in the -Y direction. The flow rate of flow path 27b and the flow path 27c are approximately the same. Branching unit 28 branches the flow path into two flow paths 28a and 28b. Flow path 28a extends in the +Y direction, and flow path 28b extends in the -Y direction. The flow rate of flow path 28a and the flow path 28b are approximately the same.

[0038] 3, the upper flow path 22 extends in the −X direction and the +Z direction from the −X direction end of the base flow path 21. The lower flow path 23 is located below the upper flow path 22 and extends in the −X direction and the −Z direction from the −X direction end of the base flow path 21. In other words, the upper flow path 22 and the lower flow path 23 branch off from the base flow path 21. The lower flow path 23 has a first region 23a connected to the base flow path 21 and a second portion 23b extending in the −X direction from the first region 23a.

[0039] The thickness of each of the upper flow passage 22 and the lower flow passage 23 is thinner than the thickness of the base flow passage 21 at the connection portion between the upper flow passage 22 and the lower flow passage 23 .

[0040] The angle α between the upper flow path 22 and the lower flow path 23 is an acute angle. Specifically, the angle α between the portion of the upper flow path 22 on the branching portion 29 side and the portion of the lower flow path 23 on the branching portion 29 side is an acute angle. In addition, the branching portion 29 where the upper flow path 22 and the lower flow path 23 branch off is located above the exhaust port 4.

[0041] As described above, in this embodiment, the main body 13 of the water jacket 7 has two flow paths 21a, 21b extending in different directions from the first water inlet 11, and each of the two flow paths 21a, 21b has a notch 24 extending upward from the lower surface 21c.

[0042] With this configuration, the flow rate of the coolant can be increased by the throttling effect of the notches 24 in the portions of the two flow paths 21a, 21b where the notches 24 are provided, making it easier for the coolant to flow to a location relatively far away from the first water port 11 (e.g., the protrusion 13e). This allows the coolant to flow throughout the entire water jacket 7. Furthermore, the flow rate of the coolant can be increased by the throttling effect of the notches 24 in the portions of the two flow paths 21a, 21b where the notches 24 are provided, ensuring cooling performance for the area surrounded by the upper portions of the two flow paths 21a, 21b (e.g., the combustion chamber). This makes it possible to suppress knocking.

[0043] Furthermore, at least one of the two flow paths 21a, 21b (for example, both) has a plurality of notches 24 formed therein.

[0044] With this configuration, stagnation (retention) of the coolant is likely to occur in the stagnation space 21d, which is a portion between the multiple cutouts 24 in the flow paths 21a and 21b. This prevents excessive cooling of the periphery of the stagnation space 21d (e.g., the cylinder bore 3a). Therefore, the heat retention effect of the cylinder bore 3a reduces cooling loss and friction. Furthermore, as described above, the throttling effect of the cutouts 24 in the portions of the two flow paths 21a and 21b where the cutouts 24 are provided increases the flow rate of the coolant, thereby ensuring cooling performance for the combustion chamber surrounded by the upper portions of the two flow paths 21a and 21b. In other words, in this embodiment, the flow paths 21a and 21b are provided with portions that increase the flow rate of the coolant and portions that allow the coolant to stagnate, thereby achieving cooling performance appropriate for the cooling target. Note that multiple cutouts 24 may be provided in only one of the flow paths 21a and 21b.

[0045] In addition, a notch 25 is provided in the flow path.

[0046] With this configuration, the flow rate of the cooling liquid can be increased by the throttle effect of the notch 25.

[0047] The first water passage port 11 is provided on the opposite side of the main body 13 to the outlet 4a of the exhaust port 4.

[0048] According to this configuration, the coolant that has flowed in from the first water passage port 11 can be easily circulated toward the exhaust port 4, and therefore the cooling performance of the water jacket 7 for the exhaust port 4 can be improved.

[0049] The main body 13 also has a base flow path 21 connected to the first water port 11 and the second water port 12, an upper flow path 22 extending from the base flow path 21, and a lower flow path 23 located below the upper flow path 22 and extending from the base flow path 21. The exhaust port 4 is located between the upper flow path 22 and the lower flow path 23.

[0050] According to this configuration, the exhaust port 4 is located between the upper flow passage 22 and the lower flow passage 23, so that the cooling performance of the water jacket 7 for the exhaust port 4 can be improved.

[0051] Moreover, the angle α between the upper flow passage 22 and the lower flow passage 23 is an acute angle.

[0052] With this configuration, the resistance to the coolant and the turbulence of the flow of the coolant at the branch point 29 between the upper flow path 22 and the lower flow path 23 are smaller than in a configuration in which the angle α between the upper flow path 22 and the lower flow path 23 is an obtuse angle, so that a decrease in the flow rate of the coolant can be suppressed, and ultimately the cooling performance of the water jacket 7 can be improved.

[0053] Furthermore, a branching portion 29 where the upper flow passage 22 and the lower flow passage 23 branch off is located above the exhaust port 4 .

[0054] With this configuration, the flow rate of the lower flow passage 23 can be made larger than the flow rate of the upper flow passage 22. Therefore, for example, the cooling performance for the combustion chamber can be improved.

[0055] The upper flow path 22 extends in the −X direction and the +Z direction from the −X direction end of the base flow path 21. That is, the upper flow path 22 extends obliquely upward from the base flow path 21.

[0056] With this configuration, the coolant flows easily from the upper flow passage 22 to the second water passage port 12.

[0057] Furthermore, the end 13b (second end) of the main body 13 is provided with a protrusion 13e that protrudes on the opposite side to the end 13a (first end).

[0058] With this configuration, end 13b has a protrusion 13e that protrudes on the opposite side from end 13a, making it easier for the coolant to flow to the tip of end 13b, i.e., tip 13g of protrusion 13e, which is a location relatively far from the first water passage 11, compared to when end 13b is flat.

[0059] Further, the end 13f of the protrusion 13e on the end 13a side has a curved shape whose cross section becomes smaller toward the tip 13g of the protrusion 13e.

[0060] With this configuration, the flow rate of the coolant can be increased by the throttling effect of the end portion 13f, and therefore, a decrease in the flow rate of the coolant between the convex portion 13e and the second water passage port 12 can be suppressed.

[0061] The cylinder head 2 has a mounting surface 2f located on the opposite side of the end 13b from the end 13a, to which the exhaust manifold 5 is attached, and the protrusion 13e protrudes toward the mounting surface 2f.

[0062] This configuration improves the cooling performance of the water jacket 7 for the mounting surface 2f and the exhaust manifold 5. This makes it possible to suppress thermal expansion of the mounting surface 2f and the exhaust manifold 5, and to suppress exhaust leakage between the mounting surface 2f and the exhaust manifold 5.

[0063] The exhaust manifold 5 is attached to the attachment surface 2f by a fastener 31.

[0064] With this configuration, it is also possible to suppress thermal expansion of the fasteners 31 that attach the exhaust manifold 5 to the attachment surface 2f.

[0065] Furthermore, the main body 13 has a plurality of branching portions 26-28 (locations) that branch into a plurality of flow paths 26a-26c, 27a-27c, 28a, 28b on a straight line L1 that extends in a direction from the end 13a toward the end 13b.

[0066] With this configuration, the main body 13 has a plurality of branching portions 26, 27, 28 that branch into a plurality of flow paths 26a-26c, 27a-27c, 28a, 28b on a straight line L1 that extends in a direction from the end 13a toward the end 13b, so that a wide area of ​​the cylinder head 2 can be cooled in a balanced manner compared to a case where there is no or only one branching point into a plurality of flow paths on the straight line L1. Furthermore, with this configuration, the balance of the flow rates of the coolant in each portion is less likely to be lost even when the flow rate of the coolant is low.

[0067] At least one of the plurality of branch portions 26 to 27 is provided between two cylinders C.

[0068] According to this configuration, the difference in cooling for the two cylinders C can be reduced, and the occurrence of knocking in the cylinder C can be suppressed.

[0069] Although the embodiments of the present invention have been described above, the above embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, format, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate. [Explanation of symbols]

[0070] 1...Internal combustion engine 2...Cylinder head 2f...Mounting surface 4...Exhaust port 4a...Exit 5...Exhaust manifold 7...Water jacket 11…1st water outlet 12…Second water outlet 13...Main body 13a...End (first end) 13b...End (second end) 13c...End (third end) 13e…Convex part 13f...end 21...Base channel 21a, 21b...flow path 21c…Bottom surface 24,25...Notch 22...Upper flow path 23…Lower flow path 26~28...Branch (location) 26a-26c, 27a-27c, 28a, 28b...flow path 29...Branch 31...Connector C...cylinder L1…straight line α…Angle

Claims

1. A cylinder head having a water jacket formed therein, The water jacket is a first water passage port through which the coolant flows; a second water passage port through which the cooling liquid flows out; a main body portion having a first end portion provided with the first water passage port, a second end portion opposite to the first end portion, and a third end portion separate from the first end portion and the second end portion and provided with the second water passage port, the main body portion connecting the first water passage port and the second water passage port and through which the cooling liquid flows; and the main body portion has a plurality of branch portions that branch the flow of the cooling liquid, a protrusion protruding from the second end portion toward the opposite side to the first end portion; a center of the convex portion and a center of the branch portion closest to the convex portion among the plurality of branch portions are coaxially positioned, In the convex portion, the flow path width is narrowest at the center of the convex portion, Cylinder head.

2. 2. The cylinder head according to claim 1, wherein an end of the protrusion on the side of the first end has a curved shape in which a cross section becomes smaller toward a tip of the protrusion.

3. a mounting surface located on the opposite side of the second end from the first end, to which an exhaust manifold is attached; The cylinder head according to claim 1 or 2, wherein the protrusion protrudes toward the mounting surface.

4. 4. The cylinder head of claim 3, wherein the exhaust manifold is attached to the mounting surface by a fastener.

5. An internal combustion engine comprising the cylinder head according to any one of claims 1 to 4.

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