JP2022010432A - Cylinder head of internal combustion engine and manufacturing method of the same - Google Patents

Abstract

To improve water conduction resistance of a coolant flowing into a water jacket formed at a cylinder head.SOLUTION: A water jacket 8 is formed in a cylinder head 1. The water jacket 8 has a coolant introduction passage 9 into which a coolant supplied from the outside flows from one end side. The coolant introduction passage 9 has a curved part 10 which is curved at a predetermined curvature. The curved part 10 forms one end part of the coolant introduction passage 9 and opens on a lower deck 5 of the cylinder head 1. The structure allows the cylinder head 1 to reduce passage resistance in the coolant introduction passage 9.SELECTED DRAWING: Figure 1

Description

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

In a water-cooled internal combustion engine, a structure in which cooling water flows from a cylinder block to a cylinder head has been conventionally known.

For example, Patent Documents 1 and 2 disclose a configuration in which the cooling water in the cylinder block flows from the cylinder block side to the cylinder head side along the cylinder axis.

In Patent Documents 1 and 2, the cooling water passage on the cylinder head side has a substantially L-shaped cross section along a plane including the cylinder axis of the introduction portion into which the cooling water from the cylinder block is introduced. Has been done.

Japanese Unexamined Patent Publication No. 5-321662 Jikken Akira 63-323589 Gazette

However, in Patent Documents 1 and 2, the flow of the cooling water introduced into the cylinder head is blocked by the L-shaped wall surface of the introduction portion.

That is, in Patent Documents 1 and 2, the cooling water vigorously collides with the wall surface of the portion where the cooling water has a substantially L-shape at the introduction portion of the cooling water passage on the cylinder head side. Therefore, in Patent Documents 1 and 2, the flow of cooling water may be disturbed at the introduction portion, and the water flow resistance may increase.

The cylinder head of the internal combustion engine according to the present invention has a water jacket formed inside, and the cooling water introduction passage of the water jacket is curved with a predetermined curvature and opens to the lower deck of the cylinder head. It is characterized by having a part.

In the cylinder head of the present invention, the passage resistance in the cooling water introduction passage can be reduced by the curved portion.

Sectional drawing of the main part of the cylinder head of the internal combustion engine which concerns on this invention. Sectional drawing of the cylinder head in the comparative example of this invention. The bottom view of the core used when casting the cylinder head of the internal combustion engine which concerns on this invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of a cylinder head 1 of an internal combustion engine according to the present invention, and is a cross-sectional view of the cylinder head 1 corresponding to a position along the line AA of FIG.

As shown in FIG. 1, the cylinder head 1 of an internal combustion engine has a substantially rectangular cross section, and has one side surface 2 to which an exhaust component (not shown) is attached and another side surface 3 to which an intake component (not shown) is attached. It has a flat upper deck 4 as an upper surface and a flat lower deck 5 as a lower surface.

The cylinder head 1 is made of, for example, an aluminum alloy. The cylinder head 1 is configured to internally combine the exhaust gas from each cylinder so that the combined exhaust gas flows through the exhaust components. That is, the cylinder head 1 is formed inside with an exhaust collecting portion (not shown) that collects the exhaust gas of each cylinder. The exhaust parts are, for example, an exhaust turbo, a manifold catalyst, and the like. The intake component is, for example, an intake manifold. The cylinder head 1 may be, for example, one in which the exhaust from each cylinder is not merged internally and an exhaust manifold is attached to one side surface 2 as an exhaust component.

The upper deck 4 of the cylinder head 1 is formed with a camshaft support portion 6 that rotatably supports the camshaft (not shown) together with the cam bracket (not shown).

The lower deck 5 of the cylinder head 1 is formed with a cavity 7 constituting the upper part of the combustion chamber. The lower deck 5 is attached to the upper surface of a cylinder block (not shown).

The cavities 7 form a part (upper part) of the combustion chamber of the internal combustion engine, and are formed in the lower deck 5 by the same number as the number of cylinders. The cavity 7 covers the upper end of the cylinder (not shown) of the cylinder block (not shown).

Further, the cylinder head 1 is formed with a water jacket 8 through which cooling water flows. The water jacket 8 is located between the upper deck 4 and the lower deck 5 in the direction along the cylinder axis axis C.

The water jacket 8 is formed so as to cover the periphery of the cavity 7 and the like, and the cooling water introduced from the cylinder block side flows through the water jacket 8.

The water jacket 8 has a cooling water introduction passage 9 into which the cooling water supplied from the cylinder block side flows in from one end side.

The cooling water introduction passage 9 has a curved portion 10 curved with a predetermined curvature. The curved portion 10 constitutes one end of the cooling water introduction passage 9 and is open to the lower deck 5 of the cylinder head 1. That is, the cooling water introduction passage 9 is open to the lower deck 5 of the cylinder head 1.

The cooling water introduction passage 9 is open between one side surface 2 of the cylinder head 1 and the cavity 7. The cooling water introduction passage 9 is open at a position adjacent to the cavity 7.

The cooling water introduction passage 9 is connected to a cooling water passage that opens in the upper deck of the cylinder block (not shown), and is an inlet for cooling water that flows into the water jacket 8 from the cylinder block side. The opening 9a of the cooling water introduction passage 9 formed in the lower deck 5 of the cylinder head 1 faces the opening of the cooling water passage formed in the upper deck (not shown) of the cylinder block (not shown).

As shown in FIG. 1, the cooling water introduction passage 9 is formed so as to follow the shape of the bottom surface 7a of the cavity 7. More specifically, the cooling water introduction passage 9 is curved from one side surface 2 side of the cylinder head 1 toward the other side surface 3 side. Further, the cooling water introduction passage 9 is formed to be curved with a predetermined curvature on a plane orthogonal to the cylinder row as shown in FIG. 1.

As shown in FIG. 1, the curved portion 10 has a predetermined curvature on the outer peripheral side inner wall surface 10a on the outer peripheral side (outer side) of the curved portion 10 and the inner peripheral side inner wall surface 10b on the inner peripheral side (inner side) of the curved portion 10. Is formed to have.

As shown in FIG. 1, the inner wall surface 11 of the cooling water introduction passage 9 is formed so as to be smoothly continuous without any angular portion along the direction in which the cooling water flows. In the specification of the present application, the inner wall surface 11 includes the inner wall surfaces 10a and 10b of the curved portion 10.

The cooling water introduction passage 9 is opened with a part of the inner wall surface 11 inclined with respect to the lower deck 5. That is, the cooling water introduction passage 9 is opened in a state where the inner wall surface 10a on the outer peripheral side and the inner wall surface 10b on the inner peripheral side of the curved portion 10 are inclined with respect to the lower deck 5.

The curved portion 10 is formed so that the center of curvature of the curved portion is located below the lower deck 5 (cylinder block side). That is, as shown in FIG. 1, the curved portion 10 is formed so that the center of curvature of the outer peripheral side inner wall surface 10a and the inner peripheral side inner wall surface 10b, which are curved wall surfaces, is located below the lower deck 5 (cylinder block side). Has been done.

Reference numeral 12 in FIG. 1 is a spark plug insertion hole into which the spark plug is inserted. Further, reference numeral 13 in FIG. 1 is a fuel injection valve insertion hole into which the fuel injection valve is inserted.

FIG. 2 is a cross-sectional view of the cylinder head 21 in the comparative example. For convenience, the same components as those in the above-described embodiment of the present invention are designated by the same reference numerals, and duplicate description will be omitted.

The cylinder head 21 of the comparative example has substantially the same configuration as the cylinder head 1 of the embodiment of the present invention described above, but the cooling water introduction passage 22 of the water jacket 8 is bent like a crank.

Therefore, in the cylinder head 21 of the comparative example, the cooling water flowing in from the cylinder block side vigorously collides with the inner wall surface 23 of the cooling water introduction passage 22 at the portion bent like a crank.

If there is a crank-shaped bent portion in the cooling water introduction passage 22 as in such a comparative example, the streamline of the cooling water flow is disturbed at this portion, the flow of the cooling water is obstructed, and the water flow resistance (water flow resistance) ( Passage resistance) will increase.

On the other hand, in the cylinder head 1 of the above-described embodiment, the curved portion 10 of the cooling water introduction passage 9 is formed so as to have a predetermined curvature, and the angle of the wall surface of the cooling water introduction passage 9 is tilted so as to follow the flow of the cooling water. Can be formed.

Therefore, the cylinder head 1 can reduce the passage resistance in the cooling water introduction passage 9.

The cylinder head 1 can increase the flow rate and the flow velocity of the cooling water introduced into the water jacket 8 by reducing the passage resistance in the cooling water introduction passage 9.

Further, the cylinder head 1 can improve (improve) the cooling of the entire cylinder head 1 and the combustion chamber of the internal combustion engine as the flow rate and flow velocity of the cooling water increase.

The cooling water introduction passage 9 is opened in a state where the inner wall surface 10a on the outer peripheral side and the inner wall surface 10b on the inner peripheral side of the curved portion 10 are inclined with respect to the lower deck 5.

As a result, the cooling water introduction passage 9 can reduce the passage resistance and introduce the cooling water from the cylinder block into the cylinder head 1 more smoothly.

The cooling water introduction passage 9 also has an inner wall surface 11 formed so as to be smoothly continuous as a whole along the flow direction of the cooling water, so that the passage resistance in the cooling water introduction passage 9 is reduced, and the water jacket 8 has a water jacket 8. The flow rate and flow velocity of the introduced cooling water can be increased.

FIG. 3 is a bottom view of the core 31 used when casting the cylinder head 1 of the internal combustion engine according to the present invention as viewed from below.

The cylinder head 1 of the above-described embodiment is cast using a core 31 as shown in FIG. The core 31 forms a water jacket 8 in the cylinder head 1. The core 31 shown in FIG. 3 shows a core 31 used when casting a cylinder head when the present invention is applied to an in-line 3-cylinder internal combustion engine. The recessed portion in the core 31 shown in FIG. 3 is a protruding portion in the cylinder head 1.

The core 31 is continuous with the main body portion 32 forming the water jacket 8, the cooling water introduction passage forming portion 33 forming the cooling water introduction passage 9, and the cooling water introduction passage forming portion 33, and the lower deck 5 of the cylinder head 1 is continuous. It has an extension portion 34 located below (cylinder block side) and an outlet portion 35 forming an outlet for cooling water in the water jacket 8.

In the extension portion 34, the portion 34a continuous with the outer peripheral side (outside) of the curve of the cooling water introduction passage forming portion 33 protrudes toward the outer peripheral side of the curve than the portion on the outer peripheral side of the curve of the cooling water introduction passage forming portion 33. It is formed like this. This is because the cooling water introduction passage 9 formed by the cooling water introduction passage forming portion 33 opens to the lower deck 5 of the cylinder head 1 in the middle of the curvature, so that the outer peripheral side of the curvature of the cooling water introduction passage forming portion 33 ( This is because the portion 34a continuous with (outside) protrudes relatively toward the outer peripheral side of the curve.

The cylinder head 1 can form a water jacket 8 having a curved cooling water introduction passage 9 by casting using such a core 31.

That is, the core 31 has an extension portion 34 projecting to the outer peripheral side of the curve with respect to the cooling water introduction passage forming portion 33, thereby setting the curved curved portion 10 for forming the cooling water introduction passage 9. It becomes possible.

At the time of casting, the portion of the cylinder head 1 formed by the extension portion 34 that protrudes from the lower deck 5 is removed by machining, for example, after casting.

1 ... Cylinder head 4 ... Upper deck 5 ... Lower deck 6 ... Camshaft support 8 ... Water jacket 9 ... Cooling water introduction passage 9a ... Opening 10 ... Inner wall surface 10a ... Outer peripheral side inner wall surface 10b ... Inner peripheral side inner wall surface

Claims (5)

In the cylinder head of an internal combustion engine in which a water jacket is formed inside
The water jacket has a cooling water introduction passage through which cooling water supplied from the outside flows in from one end side.
The cooling water introduction passage has a curved portion curved with a predetermined curvature, and has a curved portion.
The curved portion constitutes one end of the cooling water introduction passage, and is a cylinder head of an internal combustion engine characterized by opening to a lower deck of the cylinder head. The cylinder head of an internal combustion engine according to claim 1, wherein the cooling water introduction passage has an inner wall surface formed so as to be smoothly continuous along the direction in which the cooling water flows. The cylinder head of an internal combustion engine according to claim 1 or 2, wherein the cooling water introduction passage opens with a part of the inner wall surface inclined with respect to the lower deck. The cylinder head of an internal combustion engine according to any one of claims 1 to 3, wherein the curved portion has a center of curvature of the curve located below the lower deck. In the method of manufacturing a cylinder head of an internal combustion engine in which a water jacket is formed inside,
The water jacket has a cooling water introduction passage through which cooling water supplied from the outside flows in from one end side.
The cooling water introduction passage has a curved portion curved with a predetermined curvature, and has a curved portion.
The curved portion constitutes one end of the cooling water introduction passage and opens to the lower deck of the cylinder head.
The water jacket is formed using a core during casting and is formed.
The core has a cooling water introduction passage forming portion that forms the cooling water introduction passage, and an extension portion that is continuous with the cooling water introduction passage forming portion and forms a portion located below the lower deck. death,
The extension portion is characterized in that a portion continuous with the outer peripheral side of the curve of the cooling water introduction passage forming portion protrudes toward the outer peripheral side of the curve than the portion on the outer peripheral side of the curve of the cooling water introduction passage forming portion. A method for manufacturing a cylinder head of an internal combustion engine.

Images