JPH08144846A - Structure of cylinder head for engine - Google Patents

Abstract

PURPOSE: To arrange a water jacket at a proper position, and to easily insert an exhaust port forming core at a proper position. CONSTITUTION: A bending part 9 bent outward in a plane view is provided in the first exhaust port 7 being long in a distance, and the outward projecting position of the bending part 9 is overlapped upon a boss part 10 for a cylinder head fastening bolt located near the outside of an exhaust port joining part 6. At the same time, a space S between the first straight line L1 passing the opening centers O1, O2 of both exhaust port opening parts 4, 5 and the second straight line L2 extending in parallel with the first straight line L1 along the inner periphery of the boss part 10 is set up to a value being about equal to the sum of the wall thickness t1 of the boss part 10, the bore D of the first exhaust port 7 and the thickness t2 of the port wall of the first exhaust port 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a pair of intake port openings and a pair of exhaust port openings arranged in a staggered manner on the lower surface of a cylinder head, and an exhaust port merging section provided on the cylinder head. The present invention relates to a cylinder head structure for an engine, which is provided with an exhaust port that connects the exhaust port openings.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 56-79649, a pair of intake port openings are formed on the lower surface of a cylinder head in order to increase the total area of the intake port openings and increase the volumetric efficiency of the engine. With a section,
By opening both of the intake port openings along the wall surface of the combustion chamber, a swirl is formed by the flow of intake air.

Further, in order to effectively discharge the exhaust gas, a pair of exhaust port openings are formed on the lower surface of the cylinder head, and the both exhaust port openings are formed in a staggered manner so as to correspond to the both intake port openings. The one arranged is known. And in order to simplify the structure of the exhaust port,
An exhaust port merging portion is provided in the cylinder head, and the exhaust port merging portion is connected to both exhaust port openings by a long exhaust port and a short exhaust port.

[0004]

In the cylinder head structure having the above-mentioned structure, the port diameter of the exhaust port formed between the exhaust port opening and the exhaust port merging portion is ensured, and the water jacket between the ports is provided. It is required to secure the volume of On the other hand, when manufacturing the cylinder head, it is necessary to insert the core for forming the exhaust port from the side of the mold. In this case, while satisfying the above requirements,
There is a problem that it is difficult to install the core so as not to interfere with the water jacket molding core installed in the mold and the pins for forming the mounting holes of the cylinder head fastening bolts.

In order to prevent interference between the exhaust port molding core and the water jacket molding core, the water jacket molding core is arranged at a position away from the exhaust port. In the case of the above construction, there is a problem that the thickness of the exhaust port becomes unnecessarily large to increase the weight of the engine and the cooling action of the cooling water passing through the water jacket becomes insufficient.

The present invention has been made in view of the above points, and the water jacket can be disposed at an appropriate position, and the core for forming the exhaust port can be easily inserted into the installation position. It is an object of the present invention to provide a cylinder head structure for an engine that can be used.

[0007]

The invention according to claim 1 is
A pair of intake port openings and a pair of exhaust port openings are arranged in a staggered manner on the lower surface of the cylinder head, and
A cylinder head structure of an engine, wherein a first exhaust port having a long distance and a second exhaust port having a short distance connecting an exhaust port merging portion provided on a cylinder head and the exhaust port openings are formed, The first exhaust port is provided with a curved portion that is curved outward in a plan view, and the outwardly projecting position of this curved portion and the cylinder head fastening bolt located near the outside of the exhaust port confluence portion. The first straight line passing through the center of the opening of both exhaust port openings and the inner peripheral surface of the boss for the cylinder head fastening bolt, and the first straight line that overlaps with the boss for the cylinder axis in the crankshaft direction. And a second straight line extending in parallel with the wall thickness of the cylinder head fastening bolt boss, the inner diameter of the first exhaust port, and the wall thickness of the port wall of the first exhaust port. It is obtained by setting nearly equal to the sum of.

According to a second aspect of the invention, in the engine cylinder head structure according to the first aspect, a straight line passing through an opening center of a pair of intake port openings formed on the lower surface of the cylinder head, and a pair of exhaust ports. Both of the intake port openings are arranged so that the first straight line passing through the opening center of the opening is parallel.

According to a third aspect of the present invention, the pair of intake port openings and the pair of exhaust port openings are arranged in a zigzag pattern on the lower surface of the cylinder head, and the exhaust port confluence section is provided on the cylinder head. A cylinder head structure for an engine, in which a first exhaust port having a long distance and a second exhaust port having a short distance connecting the two exhaust port openings are formed, and a cylinder head structure of The straight portion extending upward is provided on the cylinder head, and the mold splitting surface of the cylinder head molding mold is set at a position higher than the upper surface of the bottom deck.

[0010]

According to the first aspect of the present invention, the opening areas of the first exhaust port and the second exhaust port which are installed adjacent to each other are formed by bending the first exhaust port having a long distance outwardly. And a first straight line passing through the center of the opening of the pair of exhaust port openings and a second straight line extending parallel to the first straight line along the inner peripheral surface of the boss portion for the cylinder head fastening bolt. By setting the interval of the above as described above, the minimum necessary space into which the core for forming the exhaust port can be inserted is formed in the installation portion of the exhaust port.

According to the second aspect of the present invention, the pair of intake port openings and the pair of exhaust port openings, which are installed on the lower surface of the cylinder head, are arranged in parallel. The above-mentioned port openings will be installed at appropriate positions in the space.

According to the third aspect of the present invention, the mold splitting surface of the cylinder head molding mold is arranged at a position corresponding to the installation height of the straight portion extending upward from both the exhaust port openings. The exhaust port molding core is divided into a first core having the exhaust port merging portion and a pair of second cores corresponding to the straight portions.

[0013]

1 and 2 show an embodiment of a cylinder head structure of an engine according to the present invention. A cylinder head 1 of this engine is applied to a multi-cylinder direct injection diesel engine, and has a pair of intake port openings 2 and 3 formed on a lower surface formed at right angles to a cylinder axis.
And a pair of exhaust port openings 4 and 5 are formed. The cylinder head 1 is fastened to the cylinder block with a plurality of cylinder head fastening bolts. Specifically, a total of 6 bolts, which are a pair of bolts located between the adjacent cylinder heads and bolts on both sides of the cylinder bore, are arranged around each cylinder. Part 10,
18 is provided.

The exhaust port openings 4 and 5 have their opening centers O1 and O2 inclined by a predetermined angle θ with respect to a center line L extending in a direction orthogonal to the crankshaft.
The exhaust port opening 4 is disposed on the upper side, and the one exhaust port opening 4 is disposed at a position separated from the installation portion of the exhaust manifold, and the other exhaust port opening 5 is disposed at a position close to the installation portion of the exhaust manifold. Has been done.

Further, the exhaust port openings 4 and 5 are connected to an exhaust port converging portion 6 formed in the cylinder head 1, a first exhaust port 7 having a long distance communicating with one exhaust port opening 4, and It is adapted to be connected to an exhaust manifold (not shown) through a two-fold shaped exhaust port having a second exhaust port 8 having a short distance communicating with the other exhaust port opening 5.

The first exhaust port 7 is provided with a curved portion 9 which is curved outward in a plane. The curved portion 9 is located at the projecting position of the curved portion 9 and in the vicinity of the outer side of the exhaust port merging portion 6. The curved portion 9 is formed so that the boss portion 10 for the cylinder head fastening bolt overlaps in the crankshaft direction.
The overhang amount is set.

A first straight line L1 passing through the center of the exhaust port openings 4 and 5 and a second straight line L2 extending along the inner peripheral surface of the boss portion 10 in parallel with the first straight line L1. The interval S is set to a value approximately equal to the sum of the inner diameter D of the first exhaust port 7, the wall thickness t1 of the boss portion 10 and the wall thickness t2 of the port wall of the first exhaust port 7.

The two exhaust port openings 4 and 5 are related to the arrangement of the intake port openings 2 and 3.
Since the installation interval of No. 5 and the distance from the cylinder axis are regulated so as to be within a preset proper range, the interval S between the first straight line L1 and the second straight line L2 should be set as described above. Thus, the inclination angle of the first straight line L1 passing through the center of the exhaust port openings 4 and 5 with respect to the center line L is set to about 15 °.

Further, straight portions 7a and 8a of a predetermined length extending upward from the exhaust port openings 4 and 5 are formed at the tips of the first and second exhaust ports 7 and 8, and these straight portions 7a are formed. , 8a is set to be located above the installation height DH of the upper surface of the bottom deck of the cylinder head 1.

Both of the intake port openings 2 and 3 are arranged on a third straight line L3 which is installed parallel to the first straight line L1 so that they are parallel to the both exhaust port openings 4 and 5. By being installed, the installation positions of the intake port openings 2 and 3 and the exhaust port openings 4 and 5 are offset in the cylinder width direction, so that the port openings 2 to 5 are provided.
Are arranged in a staggered pattern.

A pair of intake ports 11 and 12 for connecting the intake port openings 2 and 3 and an intake manifold (not shown) are formed in the cylinder head 1. The intake ports 11 and 12 are configured so that their tips are curved so as to be directed to the wall surface of the combustion chamber, and swirls are formed by the flow of intake air.

Further, the cylinder head 1 is provided with water jackets 13 to 15 for cooling the exhaust port, a fuel injection valve installation hole 16 and a glow plug installation hole 17 at predetermined positions. The boss portion 18 for the cylinder head fastening bolt has the exhaust port joining portion 6
Is disposed on the inner side of the.

The cylinder head 1 having such a structure is molded by casting, and the core for forming the exhaust port used in this casting is the second core with a two-fold shape shown in FIG. 3 and the core shown in FIG. The cylindrical second cores 20 and 21 are provided.
The first core 19 has a circular cross-section portion 22 having an outer diameter corresponding to the inner diameter of the exhaust port confluence portion 6, and first and second circular shapes corresponding to the upper portions of the first and second exhaust ports 7 and 8. Tip 2
It consists of 3,24.

The second cores 20 and 21 have outer diameters and heights corresponding to the straight portions 7a and 8a of the first and second exhaust ports 7 and 8, respectively. Then, the mold splitting surface M for the cylinder head mold is the second core 20, 2
1, that is, the straight portions 7a and 8a are disposed at positions corresponding to the installation heights of the straight portions 7a and 8a, so that the positions are set higher than the installation height DH of the bottom deck upper surface.

In order to manufacture the cylinder head 1 having the above-described structure, the second cores 20 and 21 for forming the exhaust port are installed in the cylinder head forming mold, and as shown in FIG. The cores 25 to 27, the pins 28 and 29 for molding the boss portion, and the like are installed.
Then, the first and second tip portions 23, 2 of the first core 19 are
With the tip of the first core 19 facing the inner side of the cylinder (center side of the cylinder) so that 4 does not interfere with the pins 28, 29 for molding the boss, the first core 19 Insert the tip of the into the mold.

After inserting the first core 19 to a position where the first and second tip portions 23, 24 of the first core 19 do not interfere with the pins 28, 29 for molding the boss portion. As shown in FIG. 6, by pivoting the tip of the first core 19 toward the outer side of the cylinder, the first and second tips 23 and 24 are made into cores for water jacket molding. While avoiding interference with 27 and 25 respectively,
The first core 19 is further inserted further.

Next, the first and second tip portions 23 and 24
After inserting the first core 19 to a position where there is no risk of the first core 19 interfering with the water jacket molding cores 27, 25, the first tip portion 23 causes the water jacket molding core 2 to move.
While avoiding interference with the first and second tip portions 23,
The insertion work of the first core 19 is completed by inserting 24 into the installation positions of the first and second exhaust port openings 4 and 5.

After the casting mold is set in this way, casting is performed, and after cooling, the casting mold is opened to remove the cores, pins, and the like, and the necessary finishing process is performed to finish the manufacture of the cylinder head 1.

Of the pair of intake port openings 2 and 3 and exhaust port openings 4 and 5 arranged in a staggered manner on the lower surface of the cylinder head 1 as described above, they communicate with the first exhaust port opening 4. The first exhaust port 7 having a long distance is provided with the curved portion 9 that is curved outward in a plan view, and the protruding position thereof is configured to overlap the boss portion 18 for the cylinder head fastening bolt. It is possible to sufficiently secure the cross-sectional areas of the first exhaust port 7 and the second exhaust port 8 and also secure the volume of the water jacket 15 located between the both exhaust ports 4 and 5.

Then, the first straight line L1 passing through the opening centers O1 and O2 of the exhaust port openings 4 and 5 and the first straight line L1 along the inner peripheral surface of the boss portion 10 for the cylinder head fastening bolt. S between the second straight line L2 extending in parallel with
Is set to a value approximately equal to the sum of the wall thickness t1 of the cylinder head fastening bolt boss portion 10, the inner diameter D of the first exhaust port 7, and the wall thickness t2 of the port wall of the first exhaust port 7. Therefore, the first core 19 for forming the exhaust port is formed.
It is possible to provide the mold with a space part that can be inserted into the installation part and prevent the space part from becoming larger than necessary.

Therefore, the installation space of the water jacket 13 and the first exhaust port 7 which are arranged along the inner surface of the exhaust port confluence portion 6 can be maintained without deteriorating the mountability of the first core 19. A sufficient installation space for the water jacket 14 arranged along the outer surface can be secured, and the installation space for the boss portions 10, 18 for the cylinder head fastening bolts and the exhaust port openings 4, 5 are provided. It is possible to secure a sufficient installation space for the exhaust valve and the like.

The first straight line passing through the pair of intake port openings 2 and 3 installed on the lower surface of the cylinder head 1 as described above and passing through the center O1 and O2 of the pair of exhaust port openings 4 and 5. If the intake port openings 2 and 3 are arranged in parallel with L1, the intake port openings 2 and 3 can be opened at appropriate positions and at appropriate angles in a limited space. The swirl can be effectively formed by the flow of the intake air supplied. Moreover, the opening areas of the intake port openings 2 and 3 can be sufficiently secured to improve the volumetric efficiency of the engine.

Further, the cylinder head 1 is provided with straight portions 7a and 8a extending from the both exhaust port openings 4 and 5 to the upper side of the upper surface of the bottom deck, and the installation height H of the split surface M of the cylinder head molding mold is set. Is set at a position higher than the installation height DH of the upper surface of the bottom deck, so that the water jacket arranged between the first and second exhaust port openings 4 and 5 and the installation hole 16 of the fuel injection valve. A sufficient installation depth of 14 can be secured. In addition, the core for molding the exhaust port is divided into a first core 19 having a two-fold shape and a pair of second cores 20 and 21 corresponding to the straight portions 7a and 8b.
The work of inserting the core 19 can be facilitated.

[0034]

As described above, the invention according to claim 1 has a cylinder head structure in which a pair of intake port openings and exhaust port openings are arranged in a staggered manner on the lower surface of the cylinder head. The first exhaust port, which has a long distance communicating with one of the exhaust port openings, is provided with a curved portion that is curved outward in a plan view, and the protruding position is provided on the cylinder head. Since it is configured to overlap the boss portion for the cylinder head fastening bolt located in the vicinity, it is possible to sufficiently secure the cross-sectional areas of the first exhaust port and the second exhaust port.

A first straight line passing through the center of each of the exhaust port openings and a second straight line extending parallel to the first straight line along the inner peripheral surface of the cylinder head fastening bolt boss portion. Since the interval is set to a value approximately equal to the sum of the wall thickness of the boss portion, the inner diameter of the first exhaust port, and the wall thickness of the port wall of the first exhaust port, the core for forming the exhaust port is formed. It is possible to provide the mold with a space part that can be inserted into the installation part and prevent the space part from becoming larger than necessary.

Therefore, the installation space of the water jacket disposed along the inner side surface of the exhaust port joining portion and the outside of the first exhaust port without deteriorating the mountability of the exhaust port molding core. A sufficient space for installing the water jacket arranged along the side surface can be secured, the cylinder head can be effectively cooled by the cooling water passing through the water jacket, and the weight of the cylinder head can be reduced. There are advantages.

In the invention according to claim 2, the pair of intake port openings formed on the lower surface of the cylinder head are arranged parallel to the first straight line passing through the opening centers of the pair of exhaust port openings. , The intake port opening can be arranged at a proper position in a limited space to ensure a sufficient opening area, thereby improving the volumetric efficiency of the engine and at the same time, increasing the intake port opening. The swirl can be effectively formed by the flow of air sucked into the combustion chamber from.

According to the third aspect of the present invention, a straight portion extending from the exhaust port openings above the bottom deck upper surface is provided, and the mold split surface of the cylinder head molding mold is located at a position higher than the bottom deck upper surface. Therefore, the installation depth of the water jacket arranged between the first and second exhaust port openings and the installation hole of the fuel injection valve is sufficiently secured to effectively cool this part. In addition, it is possible to insert the first core into the exhaust port molding core by dividing the core into a second-shaped mat and a pair of second cores corresponding to the straight portion. Has the advantage that it can be facilitated.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing an embodiment of a cylinder head structure of an engine according to the present invention.

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

FIG. 3 is a plan view showing the structure of a core for forming an exhaust port.

FIG. 4 is a front view showing a configuration of a core for forming an exhaust port.

FIG. 5 is an explanatory diagram showing a first stage of core insertion work.

FIG. 6 is an explanatory diagram showing a second stage of core insertion work.

[Explanation of symbols]

 1 Cylinder Head 2,3 Intake Port Opening 4,5 Exhaust Port Opening 6 Exhaust Port Converging Part 7 First Exhaust Port 8 Second Exhaust Port 7a, 8a Straight Part 9 Curved Part 10 Boss Part for Cylinder Head Fastening Bolt

Front page continued (72) Inventor Manabu Shibakawa 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (3)

[Claims] 1. A pair of intake port openings and a pair of exhaust port openings are arranged in a staggered manner on the lower surface of the cylinder head, and the exhaust port confluence section and the both exhaust port openings provided in the cylinder head are arranged. A cylinder head structure of an engine in which a first exhaust port having a long distance and a second exhaust port having a short distance connecting to and are formed,
The first exhaust port is provided with a curved portion that is curved outward in a plan view, and an outwardly projecting position of this curved portion,
The boss portion for the cylinder head fastening bolt located near the outer side of the exhaust port merging portion overlaps in the crankshaft direction, and the first straight line passing through the opening centers of both the exhaust port opening portions and the cylinder head. The distance from the second straight line that extends in parallel with the first straight line in contact with the inner peripheral surface of the fastening bolt boss is determined by the wall thickness of the cylinder head fastening bolt boss and the inner diameter of the first exhaust port. A cylinder head structure for an engine, wherein the value is set to be approximately equal to the sum of the wall thickness of the first exhaust port and the wall thickness. 2. A straight line passing through the opening centers of the pair of intake port openings formed on the lower surface of the cylinder head and a first straight line passing through the opening centers of the pair of exhaust port openings are parallel to each other. The cylinder head structure for an engine according to claim 1, wherein an intake port opening is provided. 3. A pair of intake port openings and a pair of exhaust port openings are arranged in a staggered manner on the lower surface of the cylinder head, and the exhaust port confluence section and the both exhaust port openings provided in the cylinder head are arranged. A cylinder head structure of an engine in which a first exhaust port having a long distance and a second exhaust port having a short distance connecting to and are formed,
An engine characterized in that the cylinder head is provided with a straight portion extending upwardly from the both exhaust port openings and above the upper surface of the bottom deck, and the molding surface of the cylinder head molding mold is set at a position higher than the upper surface of the bottom deck. Cylinder head structure.