JP7589183B2 - Cylinder head and internal combustion engine - Google Patents

Description

The present invention relates to a cylinder head and an internal combustion engine.

An internal combustion engine in which a water jacket is formed in the cylinder head is disclosed (see, for example, Patent Document 1).

JP 2021-55622 A

The problem with water jackets is that it is difficult to circulate the coolant to areas that are relatively far away from the water inlet through which the coolant flows from the water pump.

The present invention was made in consideration of the above, and aims to facilitate the flow of coolant to a location in the water jacket of a cylinder head that is relatively far away from the water passage through which the coolant flows.

In order to solve the above-mentioned problems and achieve the object, a cylinder head according to the present invention is a cylinder head formed with a water jacket, the water jacket having a first water passage port through which a coolant flows in, a second water passage port through which the coolant flows out, a first end portion at which the first water passage port is provided, a second end portion opposite 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, and the cylinder head has a main body portion connecting the first water passage port and the second water passage port and through which the coolant flows, the main body portion having two flow paths extending in different directions from the first water passage port, each of the two flow paths being provided with a notch extending upward from a lower surface, at least one of the two flow paths being provided with a plurality of the notches, a recess is formed in the flow path by the plurality of the notches, the recess is a portion between the plurality of the notches, and the notch on the upstream side of the flow path is lower in height than the notch on the downstream side .

With this configuration, the flow rate of the cooling liquid can be increased by the throttle effect of the notches in the portions of the two flow paths where the notches are provided, making it easier for the cooling liquid to flow to a portion relatively far from the first water passage port. Also, with this configuration, since the cooling liquid is likely to stagnate in the portions between the multiple notches in the flow paths, it is possible to prevent the surroundings of those portions from being excessively cooled.

The internal combustion engine according to the present invention is equipped with the cylinder head.

This configuration allows the effects of the cylinder head to be achieved.

The present invention makes it easier for the coolant to flow to a location in the water jacket of the cylinder head that is relatively far from the water passage through which the coolant flows.

FIG. 1 is a plan view that illustrates an internal combustion engine according to an embodiment. FIG. 2 is a perspective view showing a schematic external shape of the water jacket according to the embodiment. FIG. 3 is a cross-sectional view taken along line III-III in FIG.

Below, one embodiment of the present invention will be described with reference to Figures 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 explanations may be described using multiple expressions. The components and their explanations 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.

Figure 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.

As shown in each drawing, for the sake of 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 mutually perpendicular. The X-axis is provided along the width of the internal combustion engine 1. The Y-axis is provided along the depth of the internal combustion engine 1. The Z-axis is provided along the height of the internal combustion engine 1. In this embodiment, the Z-axis is provided along the vertical direction.

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 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 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 the Z axis arrow. The +Z direction is the upward direction. The -Z direction is the downward direction.

The internal combustion engine 1 has a cylinder head 2 and a cylinder block 3. In FIG. 1, only a portion of the cylinder block 3 is shown. Note that the cylinder head 2 and the cylinder block 3 may be separate members, or may be molded integrally to form a single block. The upper surface of the cylinder block 3 is covered by a head cover or the like.

The cylinder block 3 has two cylinder bores 3a that extend in the vertical direction. The cylinder bores 3a are included in the cylinder 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, the reciprocating motion is converted into rotation of the crankshaft by the connecting rod.

The cylinder head 2 is provided on top of the cylinder block 3. The cylinder head 2 is provided with combustion chambers in cylinders C, which are provided corresponding to each cylinder bore 3a, intake valves that open and close the intake ports that communicate with the combustion chambers, exhaust valves that open and close the exhaust ports 4 (see Figure 3) that communicate with the combustion chambers and through which exhaust flows, and spark plugs. The intake valves and exhaust valves are operated by the rotation of a camshaft that is linked to the crankshaft. The exhaust port 4 is also called the exhaust flow passage.

The cylinder head 2 has regions 2a to 2e. Regions 2a to 2d are provided for each cylinder C. Region 2a is provided with an intake valve. Region 2b is provided with an exhaust valve. Region 2c is provided with a spark plug.

The cylinder head 2 also has a mounting surface 2f on which the exhaust manifold 5 is attached. The exhaust manifold 5 is fixed to the cylinder head 2 by fasteners 31 such as bolts. The inside of the exhaust manifold 5 is connected to the outlet 4a of the exhaust port 4 (see FIG. 3).

The cylinder block 3 is also formed with a water jacket 7. Coolant (cooling water) supplied from an electric water pump flows through the water jacket 7. The arrows in Figure 1 show an example of the flow direction of the coolant.

2 is a perspective view showing a schematic external shape of the water jacket 7 according to the embodiment. As shown in FIG. 1 and FIG. 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 an inlet port through which the coolant supplied from the water pump flows. That is, the first water port 11 is an inlet port. The second water port 12 is an outlet port through which the coolant flows. The second water port is provided in the +Z direction, i.e., upward, from the first water port 11. The main body 13 connects the first water port 11 and the second water port 12, through which the coolant flows. The coolant flows into the main body 13 from the first water port 11 and flows out from the second water port 12. As a result, each part of the cylinder head 2 and each part of the cylinder block 3 are cooled by the coolant.

The main body 13 has multiple ends 13a to 13c. End 13a is the end on the +X direction side. End 13b is the end opposite end 13a. In other words, end 13b is the end on the -X direction side. End 13c is the end on the +Y direction side. The main body 13 also has an end (not shown) opposite end 13c. The end opposite end 13c is the end on the -Y direction side.

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 13a. That is, the first water passage port 11 is provided on the opposite side of the main body 13 from the outlet 4a of the exhaust port 4. A second water passage port 12 is provided at end 13c. That is, the second water passage port 12 is provided at end 13c, which is separate from end 13a and end 13b.

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

The main body 13 is formed to surround each of the regions 2a to 2e of the cylinder head 2 and sandwich the exhaust port 4.

As shown in Figures 1 to 3, the main body 13 has a base flow path 21, an upper flow path 22, and a lower flow path 23.

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

As shown in Fig. 2, each of the two flow paths 21a, 21b has two notches 24 extending from the lower surface 21c in the +Z direction, i.e., upward. The portion between the two notches 24 in 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. In addition, each of the two flow paths 21a, 21b has a notch 25 extending downward from the upper surface 21e. The stagnation space 21d is an example of a recess.

As shown in FIG. 1, the main body 13 has a plurality of branching portions 26, 27, and 28 that are points on a straight line L1 that extends 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 branching portions 26, 27, and 28, at least the branching portion 27 is provided between two cylinders C. At the branching portions 26, 27, and 28, the flow paths are branched symmetrically with respect to the straight line L1, for example. The branching portions 26, 27, and 28 are also referred to as flow path branching portions.

The branching section 26 branches the flow path into three flow paths 26a, 26b, and 26c. The flow path 26a extends in the -X direction, the flow path 26b extends in the +Y direction, and the flow path 26c extends in the -Y direction. The flow rate of the flow path 26b and the flow path 26c are approximately the same. The branching section 27 branches the flow path into three flow paths 27a, 27b, and 27c. The flow path 27a extends in the -X direction, the flow path 27b extends in the +Y direction, and the flow path 27c extends in the -Y direction. The flow rate of the flow path 27b and the flow path 27c are approximately the same. The branching section 28 branches the flow path into two flow paths 28a and 28b. The flow path 28a extends in the +Y direction, and the flow path 28b extends in the -Y direction. The flow rate of the flow path 28a and the flow path 28b are approximately the same.

As shown in FIG. 3, the upper flow path 22 extends in the -X and +Z directions from the end of the base flow path 21 on the -X side. The lower flow path 23 is located below the upper flow path 22 and extends in the -X and -Z directions from the end of the base flow path 21 on the -X side. 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.

The thickness of each of the upper flow path 22 and the lower flow path 23 is thinner than the thickness of the connection between the upper flow path 22 and the lower flow path 23 in the base flow path 21.

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

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

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 and 21b where the notches 24 are provided, making it easier for the coolant to flow to a portion relatively far away from the first water port 11 (e.g., the convex portion 13e). This allows the coolant to flow throughout the entire water jacket 7. In addition, 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 and 21b where the notches 24 are provided, ensuring cooling performance for the portion surrounded by the upper portions of the two flow paths 21a and 21b (e.g., the combustion chamber). This makes it possible to suppress the occurrence of knocking.

In addition, at least one of the two flow paths 21a, 21b (for example, both) is provided with a number of notches 24.

According to this configuration, the coolant is likely to stagnate (retain) in the stagnation space 21d, which is a portion between the multiple notches 24 in the flow paths 21a and 21b, so that the periphery of the stagnation space 21d (for example, the cylinder bore 3a) can be prevented from being excessively cooled. Therefore, the heat retention effect of the cylinder bore 3a can reduce cooling loss and friction. Also, as described above, the flow rate of the coolant can be increased by the throttling effect of the notches 24 in the portions where the notches 24 are provided in the two flow paths 21a and 21b, so that the cooling performance for the combustion chamber surrounded by the upper portions of the two flow paths 21a and 21b can be ensured. That is, in this embodiment, the flow paths 21a and 21b are provided with a portion that increases the flow rate of the coolant and a portion that causes the coolant to stagnate, thereby realizing cooling performance according to the cooling target. Note that multiple notches 24 may be provided in only one of the flow paths 21a and 21b.

The flow path also has a notch 25.

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

The first water inlet 11 is provided on the opposite side of the main body 13 from the outlet 4a of the exhaust port 4.

This configuration makes it easier for the coolant flowing in from the first water inlet 11 to flow toward the exhaust port 4, improving the cooling performance of the water jacket 7 for the exhaust port 4.

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.

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

In addition, the angle α between the upper flow path 22 and the lower flow path 23 is an acute angle.

With this configuration, the resistance to the coolant and the turbulence of the coolant flow 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 obtuse, so that the decrease in the flow rate of the coolant can be suppressed, and the cooling performance of the water jacket 7 can be improved.

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.

With this configuration, the flow rate of the lower flow passage 23 can be made greater than the flow rate of the upper flow passage 22. This can improve the cooling performance of the combustion chamber, for example.

The upper flow path 22 extends in the -X direction and the +Z direction from the end of the base flow path 21 on the -X direction side. In other words, the upper flow path 22 extends obliquely upward from the base flow path 21.

This configuration allows the coolant to easily flow from the upper flow passage 22 to the second water passage 12.

In addition, a protrusion 13e is provided on the end 13b (second end) of the main body 13, protruding on the opposite side to the end 13a (first end).

With this configuration, end 13b has a protrusion 13e that protrudes on the opposite side to end 13a, so compared to when end 13b is flat, it is easier to circulate the cooling liquid to the tip of end 13b, i.e., tip 13g of protrusion 13e, which is a location relatively far away from the first water passage 11.

In addition, the end 13f on the end 13a side of the protrusion 13e has a curved shape in which the cross section becomes smaller toward the tip 13g of the protrusion 13e.

With this configuration, the flow rate of the cooling liquid can be increased by the constricting effect of the end 13f. This makes it possible to suppress a decrease in the flow rate of the cooling liquid between the convex portion 13e and the second water passage port 12.

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

This configuration improves the cooling performance of the water jacket 7 for the mounting surface 2f and the exhaust manifold 5. This suppresses thermal expansion of the mounting surface 2f and the exhaust manifold 5, and suppresses exhaust leakage between the mounting surface 2f and the exhaust manifold 5.

The exhaust manifold 5 is also attached to the mounting surface 2f by a fastener 31.

This configuration also suppresses thermal expansion of the fasteners 31 that attach the exhaust manifold 5 to the mounting surface 2f.

The main body 13 also has multiple branching sections 26-28 (locations) on a straight line L1 extending in a direction from the end 13a toward the end 13b, which branch into multiple flow paths 26a-26c, 27a-27c, 28a, and 28b.

With this configuration, the main body 13 has multiple branching sections 26, 27, 28 that branch into multiple 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 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 on the straight line L1. Furthermore, with this configuration, even if the flow rate of the coolant is low, the balance of the flow rates of each section is less likely to be lost.

Furthermore, at least one of the multiple branch sections 26-27 is provided between the two cylinders C.

This configuration can reduce the difference in cooling between the two cylinders C and suppress the occurrence of knocking in cylinder C.

Although the embodiment of the present invention has been described above, the above embodiment is merely an example and is not intended to limit the scope of the invention. The above embodiment 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, etc. (structure, type, direction, format, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

Reference Signs List 1 internal combustion engine 2 cylinder head 2f mounting surface 4 exhaust port 4a outlet 5 exhaust manifold 7 water jacket 11 first water passage port 12 second water passage port 13 main body 13a end portion (first end portion)
13b...end (second end)
13c...end (third end)
13e: protruding portion 13f: end portion 21: base flow passage 21a, 21b: flow passages 21c: lower surface
21d...Stagnation space (recess)
24, 25: notch; 22: upper flow passage; 23: lower flow passage; 26-28: branching portion (location)
26a to 26c, 27a to 27c, 28a, 28b...flow path 29...branch 31...coupling C...cylinder L1...straight line α...angle

Claims (2)

A cylinder head having a water jacket,
The water jacket is
a first water passage port through which the cooling liquid flows;
a second water passage port through which the cooling liquid flows out;
a main body portion having a first end portion in which the first water passage port is provided, 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 in which the second water passage port is provided, the main body portion connecting the first water passage port and the second water passage port and through which the cooling liquid flows;
having
The main body portion has two flow paths extending in different directions from the first water passage port,
Each of the two flow paths is provided with a notch extending upward from the lower surface,
At least one of the two flow paths is provided with a plurality of the notches, and a recess is formed in the flow path by the plurality of the notches ,
the recessed portion is a portion between the plurality of cutouts,
A cylinder head , wherein the notch on an upstream side of the flow passage is lower in height than the notch on a downstream side of the flow passage . An internal combustion engine comprising the cylinder head according to claim 1 .

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