JPH0742612A - Cylinder head of internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the cooling performance in the cylinder head of an internal combustion engine. In a cylinder head of a multi-cylinder internal combustion engine that includes a water jacket 4 that circulates cooling water in the cylinder row direction, a recess is formed in an upper deck portion 16 facing a valve operating chamber 15 and a water jacket 4 is formed. The embossed portion 10 is formed so as to face and protrude in a convex shape.
The oil return passage 5 is opened at the bottom of the embossed portion 10 that faces the.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a cylinder head of an internal combustion engine.

[0002]

2. Description of the Related Art In internal combustion engines mounted on automobiles and the like, the thermal load on the cylinder head tends to increase with the recent increase in output, and high cooling performance is required.

As a cylinder head of a conventional internal combustion engine,
For example, there is one as shown in FIG. 9 and FIG.
6-148647, reference).

To explain this, in the cylinder head 1, the water jacket 4 is defined between the upper deck portion 16 and the lower deck portion 19. In the water jacket 4, the cooling water flows along the cylinder row direction as indicated by the arrow in the figure, and the upper deck portion 16 and the lower deck portion 1
It is designed to absorb the heat of 9.

A valve operating chamber 15 is defined above the upper deck portion 16 with a head cover (not shown). A combustion chamber 17 is defined below the lower deck portion 19 with a piston (not shown).

The cylinder head 1 has two intake ports 6 for each cylinder, two exhaust ports, four valve guide bosses 2, and a plug post for accommodating an ignition plug located between the ports. 3 are integrally formed.

The upper deck portion 16 facing the valve operating chamber 15
A plurality of oil return passages 5 for returning the lubricating oil to the oil pan are opened in the.

Upper deck portion 16 of cylinder head 1
A projection 50 is formed on the surface of the water jacket 4 so as to face the water jacket 4. An air vent hole 51 that penetrates the root portion of the protrusion 50 is formed.

The projection 50 which is raised in a convex shape bends the flow of the cooling water downward and enhances the flow velocity distribution in the vicinity of the lower deck portion 19. As a result, the amount of heat radiated from the combustion chamber wall portion 35 having a high heat load facing the combustion chamber 17 in the lower deck portion 19 to the cooling water is increased.

[0010]

However, in such a conventional cylinder head 1 for an internal combustion engine, since the projection 50 increases the wall thickness of the upper deck portion 16, the upper deck portion 16 is not supported. Radiation from the flowing lubricating oil to the cooling water flowing through the water jacket 4 causes the protrusions 5
There is a possibility that the temperature of the lubricating oil rises excessively because it is suppressed at the portion where 0 is provided.

In view of the above problems, the present invention aims to improve the cooling performance in the cylinder head of an internal combustion engine.

[0012]

The invention according to claim 1 is
In a cylinder head of a multi-cylinder internal combustion engine that defines a water jacket that circulates cooling water along the cylinder row direction between an upper deck portion that defines a valve operating chamber and a lower deck portion that defines a combustion chamber, An embossed portion is formed in the upper deck portion so as to face the valve operating chamber and be concavely recessed, and to protrude toward the water jacket in a convex shape,
An oil return passage for returning the lubricating oil to the oil pan is opened at the bottom of the embossed portion facing the valve operating chamber.

According to a second aspect of the present invention, a plurality of the embossed portions are provided in a direction orthogonal to the cylinder row direction, and an air vent passage is defined between adjacent embossed portions.

According to a third aspect of the present invention, an oil return passage wall that defines the oil return passage divides the water jacket into a lateral flow passage and a central flow passage, and a guide rib that divides cooling water into both flow passages. Make it protrude from the oil return passage wall.

According to a fourth aspect of the present invention, the projecting height of the guide rib located on the downstream side of the water jacket is made larger than that of the guide rib located on the upstream side of the water jacket.

[0016]

In the invention according to claim 1, since the embossed portion is convexly bulged facing the water jacket, the flow of the cooling water in the water jacket is bent downward by the embossed portion to the combustion chamber in the lower deck portion. The flow velocity distribution of the cooling water along the adjacent portions is enhanced. As a result, the amount of heat radiated from the combustion chamber wall of the lower deck, which has a high heat load, the exhaust port wall connected to this combustion chamber wall, the plug post, etc., to the cooling water is increased, and the cylinder head is overheated at these parts. Can be prevented.

In the valve operating chamber, the lubricating oil that lubricates the intake / exhaust valves, the cam shaft, etc. flows down to the embossed portion that is concavely recessed on the upper deck portion, and passes from the oil return passage to the oil pan via the embossed portion. Run down. The lubricating oil radiates heat to the cooling water of the water jacket through the embossed portion while passing through the embossed portion. Since the embossed portion is raised in a convex shape with respect to the water jacket, the flow rate of the cooling water flowing along the embossed portion in the water jacket is increased, and the amount of heat released from the lubricating oil to the cooling water increases, It is possible to prevent the lubricating oil from being overheated.

According to the second aspect of the present invention, a plurality of embossed portions are provided in the direction orthogonal to the cylinder row direction, and the air vent passage is defined between the adjacent embossed portions. Therefore, the air component contained in the cooling water forms the air vent passage. It is prevented from passing through the embossed part and being dammed by the convex embossed part facing the water jacket. Accordingly, it is possible to prevent the heat from being radiated from the upper deck portion to the cooling water being hindered without the air component being accumulated between the upper deck portion and the embossed portion.

In the invention according to claim 3, the water jacket is divided into a lateral flow passage and a central flow passage by an oil return passage wall defining an oil return passage, and a guide rib for dividing the cooling water into both passages is formed by an oil. Since it is projected from the return passage wall, the cooling water flowing through the water jacket is increased in amount by increasing the amount of cooling water guided to the central portion of the water jacket through the central flow path via the guide ribs.
The amount of heat radiated from the exhaust port wall, the plug post, and the like connected to the combustion chamber wall having a high heat load to the cooling water is increased, and the cylinder head can be prevented from being overheated at these portions.

In the invention of claim 4, since the protruding height of each guide rib is formed to be large from the upstream side to the downstream side of the water jacket, the cooling water flowing through the water jacket is transferred from the upstream side by heat transfer from the cylinder head 1. Although it gradually rises toward the downstream side, the amount of cooling water introduced to the central part of the water jacket via the guide ribs with different protruding heights gradually increases from the upstream side to the downstream side, so that combustion with a high heat load in each cylinder The amount of heat radiated from the exhaust port wall connected to the chamber wall, the plug post, and the like to the cooling water is ensured uniformly, and the cylinder head can be cooled uniformly in the cylinder row direction.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the cylinder head 1 is
A water jacket 4 that circulates cooling water in the cylinder column direction is defined between the upper deck portion 16 and the lower deck portion 19.

A valve operating chamber 15 is defined above the upper deck portion 16 with a head cover (not shown). The valve operating chamber 15 is provided with two cam shafts and rocker arms for opening and closing intake and exhaust valves.

As shown in FIG. 6, the lower deck portion 19 is
A combustion chamber wall portion 35 that defines the combustion chamber 17 is provided between the piston and a piston (not shown), and an intake port wall 28, an exhaust port wall 29, and a plug post 3 are formed so as to be connected to the combustion chamber wall portion 35. There is.

As shown in FIG. 4, the engine has four cylinders arranged side by side in the crankshaft direction, and the cylinder head 1 has two intake ports 6 and two exhaust ports 7 for each cylinder. The four valve guide bosses 2 and one plug post 3 that is located between the ports 6 and 7 and accommodates the spark plug are integrally formed.

The cylinder head 1 is provided at its front portion with a cooling water inlet 21 communicating with the discharge side of a water pump (not shown), and at its rear portion with a cooling water outlet 22 communicating with the suction side of the water pump. In the jacket 4, the cooling water flows along the cylinder column direction as shown by the arrow in the figure.

As shown in FIGS. 2 and 3, the upper deck portion 16 of the cylinder head 1 is integrally formed with an embossed portion 10 having a V-shaped cross section and curved. The embossed portion 10 is recessed in a concave shape facing the valve operating chamber 15 and is protruded in a convex shape facing the water jacket 4.

The embossed portion 10 is located between the cylinders and is provided across the left and right side wall portions 13 and 14 so as to be orthogonal to the cylinder row direction (crankshaft axial direction).

The cylindrical oil return passage walls 25 and 26 which define the oil return passage 5 are connected to the respective embossed portions 10. Each embossed portion 10 defines an oil reservoir chamber 9 that faces the valve operating chamber 15 and is recessed in a concave shape. An oil return passage 5 for returning the lubricating oil in the valve operating chamber 15 to an oil pan (not shown) is opened at the bottom of the oil reservoir 9.

On the left side (intake side) of the cylinder head 1, there are two oil return passage walls 25 formed between the first cylinder and the second cylinder and between the third cylinder and the fourth cylinder. Is formed by connecting to. The oil return passage walls 25 formed at the front and rear of the cylinder head 1 are the right side wall 1
It is formed by connecting to 4.

On the right side (exhaust side) of the cylinder head 1, there are three oil return passage walls 26 located between the cylinders.
Are formed apart from the right side wall portion 14. Each oil return passage wall 26 and the exhaust port wall 29 have a central flow passage 31 between them.
And a lateral flow path 32 is defined between the side wall 32 and the right side wall portion 14.

Guide ribs 41, 42, 43 are formed so as to project from the oil return passage wall 26 partitioning the flow passages 31, 32. Each of the guide ribs 41, 42, 43 is formed so as to incline toward the upstream side with respect to the flow of the cooling water and incline toward the outside at a predetermined angle with respect to the crankshaft axial direction. As a result, each of the guide ribs 41, 42, 43 has a central flow passage 31 of the water jacket 4 as shown by an arrow in FIG.
And the amount of cooling water branched to the side flow passage 32 is adjusted to a predetermined ratio.

In this embodiment, each guide rib 41, 4
The protruding heights of 2, 43 are formed to be equal.

With the above construction, the operation will be described below.

The cooling water sent from the water pump is shown in FIG.
In the process of flowing in from the inlet 21 and flowing through the water jacket 4 as indicated by an arrow, heat of the upper deck portion 16, the lower deck portion 19, the exhaust port wall 29, the plug post 3 is absorbed, and a radiator (not shown) from the outlet 22 is provided. Be led to.

Since the embossed portion 10 is raised in a convex shape facing the water jacket 4, the flow of cooling water is bent downward as indicated by the arrow in FIGS. 2 and 3.
The flow velocity distribution near the lower deck portion 19 is enhanced. As a result, the heat radiation amount from the combustion chamber wall portion 35 facing the combustion chamber 17 in the lower deck portion 19 and having a high heat load, the exhaust port wall 29 connected to the combustion chamber wall portion 35, and the plug post 3 to the cooling water is reduced. It is possible to prevent the cylinder head 1 from being overheated at these portions by increasing the height.

The cooling water flowing through the water jacket 4 is
The guide ribs 41, 42, 43 divide the flow into the lateral flow passage 32 and the central flow passage 31. Each guide rib 41, 42, 43
As a result, the amount of cooling water introduced from the central flow passage 31 to the central portion of the water jacket 4 is increased, so that the exhaust port wall 29 connected to the combustion chamber wall portion 35 having a high heat load in the second, third, and fourth cylinders, The amount of heat radiated from the plug post 3 to the cooling water is increased, and the cylinder head 1 can be prevented from being overheated at these portions.

In the first cylinder, the cooling water flowing from the inlet 21 into the water jacket 4 is guided to the central portion of the water jacket 4, so that the cooling water flows from the exhaust port wall 29 connected to the combustion chamber wall 35 and the plug post 3. The amount of heat released to

By thus guiding the flow of the cooling water through the embossing portion 10 and the guide ribs 41, 42, 43, the cooling performance of the combustion chamber wall portion 35 is sufficiently increased without increasing the discharge flow rate of the water pump. Therefore, the occurrence of knocking and the like can be suppressed, and high output can be achieved while reducing fuel consumption.

In the valve operating chamber 15, the lubricating oil that has lubricated the intake / exhaust valves, rocker arms, cam shafts, etc. is recessed on the upper deck portion 16 to form an oil reservoir chamber 9 in the embossed portion 10.
To the oil pan (not shown) through the oil reservoir 9 and the oil return passage 5. The lubricating oil radiates heat to the cooling water of the water jacket 4 via the embossed portion 10 while passing through the oil reservoir 9. Since the embossed portion 10 is raised in a convex shape facing the water jacket 4, the flow velocity of the cooling water flowing along the embossed portion 10 in the water jacket 4 is increased, so that the lubricating oil is carried away to the cooling water. The amount of heat is increased, and it is possible to prevent the lubricating oil from overheating.

Since the three oil return passage walls 26 located between the cylinders on the right side of the cylinder head 1 are formed apart from the right side wall portion 14, each oil return passage wall 26 is covered with water over its entire circumference. By facing the jacket 4,
The amount of heat released from the lubricating oil to the cooling water is increased, and the lubricating oil can be prevented from being overheated.

Further, since the guide ribs 41, 42, 43 are formed so as to project from each oil return passage wall 26, the rigidity of the cylinder head 1 is enhanced.

Next, another embodiment shown in FIG. 7 will be described. It should be noted that the same reference numerals are used for the portions corresponding to those in FIGS.

Upper deck portion 16 of cylinder head 1
Two embossed portions 10, which have a V-shaped cross section and are curved, are formed side by side between the left and right side wall portions 13 and 14.

The air vent passage 12 is provided between the two embossed portions 10 and the upper deck portion 16 which are provided side by side.
Is defined.

In this case, two adjacent embossed portions 10
Since the air vent passage 12 is defined between the upper deck portion 16 and the upper deck portion 16, the air component contained in the cooling water tends to flow along the upper deck portion 16, but has a convex shape facing the water jacket 4. It passes through the water jacket 4 through the air vent passage 12 without being dammed by the raised embossed portion 10. As a result, it is possible to prevent the heat from being radiated from the upper deck portion 16 to the cooling water being hindered without accumulating the air component between the upper deck portion 16 and the embossing portion 10.

Next, another embodiment shown in FIG. 8 will be described. It should be noted that the same reference numerals are used for the portions corresponding to those in FIGS.

Guide ribs 41, 42, 43 are formed so as to project from the oil return passage wall 26 partitioning the flow paths 31, 32, and the projecting height of the guide ribs 41, 42, 43 gradually increases from the upstream side to the downstream side of the water jacket 4. It is formed to be large. Each guide rib 41, 42, 43
The cross-sectional area of the lateral flow passage 32 defined between the right side wall portion 14 and the right side wall portion 14 is formed to gradually decrease from the upstream side to the downstream side of the water jacket 4.

In this case, the temperature of the cooling water flowing through the water jacket 4 gradually rises from the upstream side to the downstream side due to the heat transfer from the cylinder head 1, but the guide ribs 41, 42, 43 having different projecting heights from each other. ,
By gradually increasing the amount of cooling water introduced to the central portion of the water jacket 4 in the order of the second, third, and fourth cylinders,
In each cylinder, the amount of heat released from the exhaust port wall 29 connected to the combustion chamber wall portion 35 having a high heat load, the plug post 3 and the like to the cooling water is evenly secured. As a result, even in the fourth cylinder located on the most downstream side of the water jacket 4, the cooling property of the combustion chamber wall portion 35 is sufficiently secured, and knocking and the like can be suppressed.

[0050]

As described above, according to the first aspect of the present invention, cooling water is provided in the cylinder row direction between the upper deck portion defining the valve operating chamber and the lower deck portion defining the combustion chamber. In a cylinder head of a multi-cylinder internal combustion engine that defines a water jacket for circulation, an embossed portion that is concavely recessed in the upper deck portion facing the valve operating chamber and is convexly raised facing the water jacket. Since the oil return passage for returning the lubricating oil to the oil pan is opened at the bottom of the embossed portion that faces the valve operating chamber, heat dissipation to the cooling water is promoted from the portion of the lower deck portion close to the combustion chamber, It is possible to improve the knocking resistance of the engine and to prevent the lubricating oil from radiating heat to the cooling water via the embossed portion, thereby preventing the lubricating oil from being overheated.

According to the second aspect of the present invention, a plurality of embossed portions are provided in the direction orthogonal to the cylinder row direction, and the air vent passage is defined between the adjacent embossed portions. Therefore, the air component contained in the cooling water forms the air vent passage. Through the embossing section,
It is possible to prevent the heat from being dissipated from the lubricating oil to the cooling water via the upper deck portion, and to prevent the lubricating oil from being overheated, without collecting the air component between the upper deck portion and the embossed portion.

According to a third aspect of the present invention, the water jacket is divided into a lateral flow passage and a central flow passage by an oil return passage wall defining an oil return passage, and a guide rib for dividing the cooling water into both flow passages is formed by an oil. Since it is projected from the return passage wall, the cooling water flowing through the water jacket 4 increases in the amount of the cooling water that is guided to the central portion of the water jacket through the central flow path through the guide ribs, so that the combustion chamber wall with a high heat load is introduced. Radiation from the exhaust port wall, plug post, etc. connected to the section to the cooling water is promoted, and the knocking resistance of the engine is enhanced.

According to the fourth aspect of the present invention, since the protruding height of the guide ribs located on the downstream side of the water jacket is made larger than that of the guide ribs located on the upstream side of the water jacket, the portion of the cylinder head close to the combustion chamber is covered with water. The jacket can be cooled uniformly from the upstream side to the downstream side.

[Brief description of drawings]

FIG. 1 is a perspective view of a cylinder head showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line CC of FIG. 5 and taken along line FF of FIG.

FIG. 5 is a sectional view taken along line D-D of FIG.

FIG. 6 is a sectional view taken along line EE of FIG.

FIG. 7 is a perspective view of a cylinder head showing another embodiment.

FIG. 8 is a sectional view taken along the line C-C in FIG. 5, showing still another embodiment.

FIG. 9 is a perspective view of a cylinder head showing a conventional example.

FIG. 10 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 Cylinder Head 4 Water Jacket 5 Oil Return Passage 6 Intake Port 7 Exhaust Port 9 Oil Storage Chamber 10 Embossing 12 Air Venting Passage 15 Valve Chamber 16 Upper Deck 17 Combustion Chamber 19 Lower Deck 26 Oil Return Passage Wall 31 Central Passage 32 Side flow passage 41 Guide rib 42 Guide rib 43 Guide rib

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02F 1/38 B 8503-3G (72) Inventor Yasuyuki Iwade 2 Takaracho, Kanagawa-ku, Kanagawa Prefecture Within Nissan Motor Co., Ltd.

Claims (4)

[Claims] 1. An upper deck portion that defines a valve operating chamber,
In a cylinder head of a multi-cylinder internal combustion engine that defines a water jacket that circulates cooling water along the cylinder row direction between the lower deck part that defines a combustion chamber, the upper deck part, and the valve operating chamber. An oil return passage is formed at the bottom of the embossed portion facing the water jacket, forming an embossed portion facing the water jacket and protruding in a convex shape facing the water jacket. A cylinder head of an internal combustion engine characterized by being made. 2. The cylinder head for an internal combustion engine according to claim 1, wherein a plurality of the embossed portions are provided in a direction orthogonal to the cylinder row direction, and an air vent passage is defined between adjacent embossed portions. 3. An oil return passage wall defining the oil return passage divides the water jacket into a lateral flow passage and a central flow passage, and a guide rib for dividing cooling water into both flow passages is projected from the oil return passage wall. The cylinder head for an internal combustion engine according to claim 1 or 2, wherein 4. The cylinder head for an internal combustion engine according to claim 3, wherein the projecting height of the guide rib located on the downstream side of the water jacket is made larger than that of the guide rib located on the upstream side of the water jacket.