Cylinder head of internal combustion engine

Abstract

The first water jacket (12) has a plurality of first cooling water inlet portions (16) at the center and two first cooling water outlet portions (17) on a side surface of a cylinder head on which an exhaust component is mounted. The interval between the first cooling water outlet portions (17) located on both sides in the cylinder row direction is greater than the interval between the first cooling water inlet portions (16) located on both sides in the cylinder row direction. The first internal thread portion (19) is formed to protrude into the first water jacket (12) and is located on the inner side of the two first cooling water outlet portions (17) in the cylinder row direction. A bulge portion (21) extending from the front end of the first internal thread portion (19) toward the side where the first cooling water inlet portion (16) is located is formed on the cylinder head (11) and protrudes into the first water jacket (12).

Description

Technical Field

[0001] The invention relates to a cylinder head of an internal combustion engine. Background Art

[0002] For example, Patent Document 1 discloses a cylinder head in which a mounting flange of an exhaust pipe is fixed by bolts. The cylinder head disclosed in Patent Document 1 has a water jacket formed inside along the cylinder row. The cylinder head of Patent Document 1 is formed so that a boss portion for mounting the exhaust pipe protrudes into the water jacket.

[0003] However, the flow pattern of the cooling water in the water jacket is not fixed in the cylinder head disclosed in Patent Document 1. Therefore, the flow of the cooling water around the boss portion is weak in the cylinder head disclosed in Patent Document 1. When the cooling water around the boss portion settles, the boss portion may not be sufficiently cooled.

[0004] That is, with the cylinder head disclosed in Patent Document 1, if the exhaust pipe becomes hot during operation and the boss portion becomes hot, fatigue occurs in the threaded portion between the boss portion and the bolt, and the bolt may become loose.

[0005] That is, there is room for further improvement in the cylinder head in terms of cooling the boss portion on which the high-temperature exhaust components are mounted.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-161129 Summary of the invention

[0007] The cylinder head of the internal combustion engine involved in the present invention comprises: a water jacket, which discharges cooling water introduced from multiple inlet portions in the center from multiple outlet portions on a side of the cylinder head on which the exhaust component is installed; multiple internal threaded portions, which are formed on one side of the above-mentioned cylinder head; and multiple bulging portions, which protrude into the above-mentioned water jacket.

[0008] The outlet portion is formed so that a distance between the outlet portions located on both sides in the cylinder bank direction is larger than a distance between the inlet portions located on both sides in the cylinder bank direction.

[0009] The internal thread portion protrudes into the water jacket and is formed between outlet portions located on both sides of the outlet portions in the cylinder row direction.

[0010] The bulging portion is formed to extend from a front end of the internal thread portion toward a side where the inlet portion is located.

[0011] Thus, the cylinder head can guide a portion of the cooling water flowing in from the inlet of the water jacket to the periphery of the internal threaded portion, and can enhance the flow of the cooling water around the internal threaded portion. Therefore, the cylinder head of the internal combustion engine involved in the present invention can efficiently cool the internal threaded portion where the exhaust component is mounted. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a bottom view of a core used when casting the cylinder head of the internal combustion engine according to the present invention.

[0013] Figure 2 It is a perspective view of a core used when casting a cylinder head of an internal combustion engine according to the present invention.

[0014] Figure 3 It is a perspective view of the first core forming the first water jacket on the cylinder block side.

[0015] Figure 4 It is along Figure 1 Cross-sectional view of the first core along line AA.

[0016] Figure 5 It is a cross-sectional view of a main part of a cylinder head of an internal combustion engine according to the present invention. DETAILED DESCRIPTION

[0017] Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

[0018] Figure 1 This is a bottom view of a core 1 used when casting a cylinder head 11 of an internal combustion engine according to the present invention, as seen from below. Figure 2 This is a perspective view of a core 1 used when manufacturing a cylinder head 11 of an internal combustion engine according to the present invention, as seen from obliquely below. Figure 3 It is a perspective view of a first core 2 for forming a first water jacket 12 on the cylinder block side, among cores 1 used when casting a cylinder head 11 of an internal combustion engine according to the present invention. Figure 4 It is along Figure 1 A cross-sectional view of the first core 2 taken along line AA. Figure 5 1 is a cross-sectional view of a main part of a cylinder head 11 of an internal combustion engine according to the present invention, and is equivalent to a cross-sectional view taken along Figure 1 A cross-sectional view of the cylinder head 11 taken along line AA.

[0019] In addition, the internal combustion engine of the embodiment is an inline 3-cylinder engine. Figure 1 to Figure 4 The core 1 shown is a structure used when the internal combustion engine is an inline three-cylinder engine.

[0020] In addition, for the sake of convenience, when describing the cylinder head 11, Figure 1 to Figure 4 The corresponding positions of the core 1 shown are marked with reference numerals for explanation. Figure 1 to Figure 4 For convenience, the parts of the core 1 marked with the second digit of the reference numerals are described as parts corresponding to the cylinder head 11. For example, Figure 1 The portion denoted by reference numeral 12 corresponds to the first water jacket 12 of the cylinder head 11 . Figure 1 to Figure 4 The recessed portion of the core 1 shown is the protruding portion of the cylinder head 11 .

[0021] The cylinder head 11 of the internal combustion engine is made of, for example, aluminum alloy, and an exhaust component (not shown) is mounted on one side (one side of the cylinder head) and an intake component (not shown) is mounted on the other side (the other side of the cylinder head).

[0022] The cylinder head 11 is configured so that the exhaust gas from each cylinder merges therein and the merged exhaust gas flows through the exhaust member. That is, the cylinder head 11 has an exhaust converging portion formed therein for merging the exhaust gas from each cylinder.

[0023] The exhaust component is, for example, an exhaust turbine, a manifold catalyst, etc. The intake component is, for example, an intake manifold.

[0024] use Figure 1 to Figure 4 The core 1 shown is used to cast a cylinder head 11 of an internal combustion engine. The core 1 forms a first water jacket 12 and a second water jacket 13 in the cylinder head 11, and is a general term for the first core 2 and the second core 3 in the present specification.

[0025] The first core 2 forms a first water jacket 12 as a water jacket. Figure 5 As shown, the first water jacket 12 cools the cylinder block side, which is the lower cover 14 side (lower surface side) of the cylinder head 11 .

[0026] The second core 3 forms the second water jacket 13. Figure 5 As shown, the second water jacket 13 cools the upper cover 15 side (upper surface side) of the cylinder head 11 which is farther from the cylinder block (not shown).

[0027] like Figure 2 As shown, the first core 2 and the second core 3 are arranged inside the mold in a manner separated in the vertical direction when casting the cylinder head 11. That is, the first water jacket 12 on the lower cover 14 side and the second water jacket 13 on the upper cover 15 side located above the first water jacket 12 are formed inside the cylinder head 11 in a manner of stacking in a separated state. In other words, the first water jacket 12 and the second water jacket 13 form a two-layer water jacket in the cylinder head 11.

[0028] The first water jacket 12 has two first cooling water inlet portions 16 and two first cooling water outlet portions 17 .

[0029] like Figure 1 , Figure 2 and Figure 4 As shown, the first cooling water inlet portion 16 as an inlet portion is formed in a straight line along the cylinder row direction of the first water jacket 12 (cylinder head 11). The first cooling water inlet portion 16 is located between the cylinders of the cylinder head 11. The first cooling water inlet portion 16 is formed at a central position of the first water jacket 12 (cylinder head 11) in a direction perpendicular to the cylinder row. The first cooling water inlet portion 16 opens at the lower cover 14 of the cylinder head 11 opposite to the upper cover (not shown) of the cylinder block (not shown). The first cooling water inlet portion 16 allows cooling water to flow in from a cooling water passage (cylinder block side water jacket) formed in the cylinder block (not shown).

[0030] like Figure 1 and Figure 2 As shown, the first cooling water outlet 17 as an outlet is located on one side of the cylinder head 11 and is formed in a straight line along the cylinder row direction. The first cooling water outlet 17a is formed at one end side of the cylinder head 11 in the cylinder row direction. The first cooling water outlet 17b is formed at the other end side of the cylinder head 11 in the cylinder row direction.

[0031] The interval between the two first cooling water outlet portions 17 is formed to be larger than the interval between the two first cooling water inlet portions 16 along the cylinder row direction. In other words, the first cooling water outlet portions 17 are formed so that the interval between the first cooling water outlet portions 17 located on both sides in the cylinder row direction is larger than the interval between the first cooling water inlet portions 16 located on both sides in the cylinder row direction. In addition, the two first cooling water outlet portions 17 are formed so as to be located on both sides of the two first cooling water inlet portions 16 in the cylinder row direction.

[0032] That is, the two first cooling water inlet portions 16 are formed to be located between the two first cooling water outlet portions 17 in the cylinder row direction. In other words, the first cooling water inlet portion 16 is formed to be located between the first cooling water outlet portions 17 located on both sides in the cylinder row direction.

[0033] The second water jacket 13 has two second cooling water inlet portions 18 and a second cooling water outlet portion (not shown). The cooling water passing through the first cooling water outlet portion 17 is introduced into the second cooling water inlet portion 18 .

[0034] Specifically, the cooling water passing through the first cooling water outlet portion 17 directly below is introduced into the second cooling water inlet portion 18. That is, the cooling water passing through the first cooling water outlet portion 17a is introduced into the second cooling water inlet portion 18a, and the cooling water passing through the first cooling water outlet portion 17b is introduced into the second cooling water inlet portion 18b.

[0035] The cooling water introduced into the second water jacket 13 is discharged to the outside from the second cooling water outlet portion.

[0036] A plurality of internal threads for mounting the exhaust components are formed on one side of the cylinder head 11. The plurality of internal threads are formed as two boss-shaped first internal threads 19 formed on the lower cover 14 side of the cylinder head 11, and a plurality of boss-shaped second internal threads (not shown) formed on the upper cover 15 side of the cylinder head 11.

[0037] During operation of the internal combustion engine, the heat of the high-temperature exhaust component is conducted to the internal thread for mounting the exhaust component. In particular, the first internal thread portion 19 on the lower cover 14 side close to the combustion chamber is more likely to become hotter than the second internal thread portion on the upper cover 15 side. The exhaust component is mounted on the cylinder head 11 using bolts (not shown) inserted into the internal thread.

[0038] like Figure 1 to Figure 3 and Figure 5 As shown, the first internal thread portion 19 as the internal thread portion is formed so that the front end thereof points to the other side surface of the cylinder head 11 and protrudes into the first water jacket 12. Figure 1 to Figure 3 The core 1 is shown, and therefore the recessed portion of the core 1 becomes the first internal thread portion 19 of the cylinder head 11 .

[0039] The first internal thread portion 19 is formed to be located inside the two first cooling water outlet portions 17 in the cylinder row direction. In other words, the first internal thread portion 19 is formed between (inside) the first cooling water outlet portions 17 located on both sides in the cylinder row direction.

[0040] like Figure 1 to Figure 3 As shown, the cylinder head 11 has a boss-shaped cylinder head bolt boss portion 20 at a position adjacent to the first cooling water inlet portion 16. Figure 1 to Figure 3 The core 1 is shown, and thus the hole portion of the core 1 becomes the cylinder head bolt boss portion 20 of the cylinder head 11 .

[0041] The cylinder head bolt boss portion 20 is located on one side of the cylinder head 11 of the first cooling water inlet portion 16. A cylinder head bolt (not shown) for fixing the cylinder head 11 to a cylinder block (not shown) passes through the inside (inner side) of the cylinder head bolt boss portion 20. The cylinder head bolt (not shown) passes through a boss hole (not shown) formed in the cylinder head bolt boss portion 20. The boss hole is formed by, for example, machining (drilling) after casting the cylinder head 11.

[0042] like Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, the cylinder head 11 has two bulging portions 21 adjacent to the first internal thread portion 19 and protruding into the first water jacket 12. Figure 1 , Figure 2 and Figure 4 The core 1 is shown, and thus the recessed portion of the core 1 becomes the bulged portion 21 of the cylinder head 11 .

[0043] The bulged portion 21 extends from the front end of the first internal thread portion 19 toward the first cooling water inlet portion 16. The bulged portion 21 is formed so as to be located between the cylinder head bolt boss portion 20 and the first internal thread portion 19.

[0044] like Figure 5 As shown, the bulge 21 is formed so that the first water jacket 12 has a predetermined passage cross-sectional area at the position where the bulge 21 is formed. That is, the upper end of the bulge 21 is not connected to the upper wall surface of the first water jacket 12.

[0045] The cooling water flowing into the first water jacket 12 flows from the first cooling water inlet 16 toward the first cooling water outlet 17. Figure 1 As shown by arrows P1, P2, and P3 in FIG. 1 , a portion of the cooling water flowing into the first water jacket 12 flows from the first cooling water inlet portion 16 toward one side of the cylinder head, crosses the periphery of the first internal thread portion 19 in the cylinder row direction, and flows toward the first cooling water outlet portion 17 .

[0046] like Figure 1 As shown by the middle arrow P1, a part of the cooling water flowing into the first water jacket 12 flows from the first cooling water inlet 16 toward one side of the cylinder head. That is, a flow of cooling water from the first cooling water inlet 16 toward a direction orthogonal to the cylinder bank (the short side direction of the cylinder head 11) occurs in the first water jacket 12. This is because the first cooling water inlet 16 and the first cooling water outlet 17 are formed to be offset in a direction orthogonal to the cylinder bank.

[0047] Here, in the cylinder head 11 of the present embodiment, the bulged portion 21 extending from the front end of the first internal thread portion 19 toward the side where the first cooling water inlet portion 16 is located is formed to protrude into the first water jacket 12 .

[0048] Therefore, if Figure 1As shown by the middle arrow P2, the cylinder head 11 can guide the cooling water bypassing the bulge 21 to the periphery of the first internal thread portion 19, so that the flow of the cooling water around the first internal thread portion 19 is enhanced. That is, the cylinder head 11 has the bulge 21, thereby reducing the flow of the cooling water (cooling water directly from the first cooling water inlet portion 16 to the first cooling water outlet portion 17 (arrow P4)) flowing at the portion where the bulge 21 is formed, and relatively increasing the flow of the cooling water (arrow P2) flowing around the first internal thread portion 19. In addition, the cylinder head 11 can efficiently cool the first internal thread portion 19, which is more likely to become high temperature than the second internal thread portion.

[0049] like Figure 1 As shown by the middle arrow P3, the cooling water introduced into the periphery of the first internal thread portion 19 flows toward the first cooling water outlet portion 17. This is because the two first cooling water outlet portions 17 are formed to be located on both sides (outside) of the first cooling water inlet portion 16 in a manner that sandwiches all (two) first cooling water inlet portions 16 in the cylinder row direction.

[0050] If the first internal thread portion 19 is heated to a high temperature, fatigue may occur in the internal thread formed in the first internal thread portion 19 and the external thread of the bolt inserted in the first internal thread portion 19 .

[0051] The cylinder head 11 can efficiently cool the first internal thread portion 19 which is more likely to become hotter than the second internal thread portion, so that the first internal thread portion 19 can be prevented from becoming hot, and fatigue of the internal thread of the first internal thread portion 19 can be prevented. In addition, the cylinder head 11 can prevent the bolt inserted into the first internal thread portion 19 from becoming hot, and fatigue of the external thread of the bolt can be prevented. That is, the cylinder head 11 can efficiently cool the first internal thread portion 19 for mounting the exhaust component, and loosening of the bolt of the first internal thread portion 19 can be prevented.

[0052] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.

[0053] For example, the number of the first internal thread portions 19 on the lower cover 14 side is not limited to 2, and may be greater than or equal to 3. The number of the bulging portions 21 is not limited to 2, and may be increased according to the number of the first internal thread portions 19.

[0054] Furthermore, the present invention is also applicable to a cylinder head of a multi-cylinder internal combustion engine having three or more cylinders, or a cylinder head having three or more first cooling water inlet portions 16 .

[0055] Furthermore, the present invention can also be applied to a cylinder head in which one (one layer) water jacket is provided inside.

Claims

1. A cylinder head for an internal combustion engine, wherein: The cylinder head of the internal combustion engine has: A water jacket in the cylinder head, which discharges cooling water introduced from a plurality of inlet portions through a plurality of outlet portions; a plurality of internal thread portions, which are formed with internal threads for mounting exhaust components; and a plurality of bulging portions, which protrude into the water jacket. The inlet portion is arranged along the cylinder row direction and formed at the center of the water jacket. The outlet portions are arranged along the cylinder row direction and formed on one side of the cylinder head on which the exhaust component is mounted, and the intervals between the outlet portions located on both sides in the cylinder row direction are larger than the intervals between the inlet portions located on both sides in the cylinder row direction. The internal threaded portion is provided on one side of the cylinder head, protrudes into the water jacket, and is formed between the outlet portions located on both sides in the cylinder row direction of the outlet portion. The bulging portion is formed to extend from the front end of the internal thread portion toward the side where the inlet portion is located. The water jacket exists around the internal thread portion.

2. The cylinder head of an internal combustion engine according to claim 1, wherein: A cylinder head bolt boss portion is provided at a position adjacent to the inlet portion. The bulging portion is located between the boss portion of the cylinder head bolt and the internal thread portion.

3. The cylinder head of an internal combustion engine according to claim 1 or 2, wherein: The bulging portion is formed such that an upper end of the bulging portion is not connected to an upper wall surface of the water jacket.

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