JPH11101158A - Manufacture of cylinder head for direct injection type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily insert an exhaust port forming core into a specified position so as to improve productivity by devising the tip part shape of the exhaust port forming core at the time of inserting the exhaust port forming core in a cooling water jacket forming core to cast a cylinder head. SOLUTION: Two exhaust ports formed cylinder by cylinder in a cylinder head are so formed as to become a single exhaust port where flow from a throat part of each port joins on the way, and a cooling water passage is formed between each throat part and an injection nozzle fitting boss of each cylinder. In the case of casting such a cylinder head, at the time of inserting an exhaust port forming core 17 in a cooling water jacket forming core 18, a part 17a of the peripheral surface of a tip part 17A to be one exhaust port forming part of the core 17 is cut in plane shape so that the tip part 17A can pass through an injection nozzle fitting boss forming part 18A of the core 18. After casting, a formed plane shape part is cut in curved surface shape 17B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cylinder head of a direct injection type internal combustion engine such as a direct injection type diesel engine and a gasoline engine, and more particularly to a technique for forming a cooling water passage in a cast cylinder head.

[0002]

2. Description of the Related Art Conventionally, a cylinder head has two direct-acting intake valves and two exhaust valves, respectively, and the cylinder head has four intake and exhaust ports which are opened and closed by the four valves. A direct injection type diesel engine of a center nozzle type and a gasoline engine of a center plug type having a fuel injection valve at a portion corresponding to a substantially central portion of the port of the cylinder head are known.

[0003] In such a direct injection type internal combustion engine, conventionally, a structure in which a fuel injection valve or a spark plug is attached to a cylinder head, and a housing in which a nozzle holder as a fuel injection valve body or a mounting hole for a spark plug is formed in the cylinder head. One that is integrally molded is employed.

[0004]

However, for example, in such a conventional cylinder head structure of a direct injection type diesel engine, a housing for mounting a nozzle holder is integrally formed with the cylinder head as described above. Because of this configuration, the outer peripheral wall of the housing and the port wall integrally formed with the cylinder head must be partly connected.

For this reason, it is difficult to form a cooling water passage between the outer peripheral wall of the housing and the port wall, particularly, the exhaust port wall.
In particular, it is difficult to secure a sufficiently large cooling water passage around the exhaust port wall. In addition, if it is attempted to secure a sufficiently large cooling water passage around the nozzle holder and the port wall, the size of each port must be reduced, and this impairs the engine performance. .

For this reason, conventionally, a cooling water jacket forming core is divided into upper and lower parts to secure a sufficiently large cooling water passage around the nozzle holder and the port wall. However, in this method, needless to say, productivity is poor, and burrs are generated at portions corresponding to the mating surfaces of the cooling water jacket forming cores above and below the completed cylinder head. There is a drawback that requires extensive post-processing.

[0007] As a technique for manufacturing a cylinder head, an apparatus for forming a core type for a cooling water jacket in a cylinder head for an internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 6-304696 and Japanese Patent Application Laid-Open No. 8-276243 are disclosed. Although known cores for cylinder head molds are known, none of these techniques can solve the above-mentioned problems. Therefore, the present invention has been made to solve the above-described conventional problems, and at least two exhaust valves for each cylinder are connected to each other.
In a method for manufacturing a cylinder head of a direct injection type internal combustion engine, each of which is arranged so as to be arranged in parallel in a direction substantially perpendicular to a central axis direction of a crankshaft and a mounting boss of a fuel injection nozzle is integrally formed with a cylinder head, It is an object of the invention to facilitate formation of a cooling water passage while improving the performance.

[0008]

For this reason, the invention according to claim 1 is characterized in that a cylinder head made of casting has two cylinders for each cylinder.
One or three intake valves and two exhaust valves, and the cylinder head has four or five ports for intake and exhaust respectively opened and closed by the four or five valves for each cylinder. The two exhaust valves are arranged in parallel in a direction substantially orthogonal to the central axis direction of the crankshaft, and the two exhaust ports are connected to a single port where the flow from the throat portion of each port joins on the way. A fuel injection nozzle is provided on the side wall surface of the cylinder head as an exhaust port, and a fuel injection nozzle is provided upright on a substantially central axis of a cylinder bore of each cylinder of the cylinder head. A method of manufacturing a cylinder head of a direct injection type internal combustion engine, wherein a cooling water passage is formed between each throat portion of two exhaust ports and a mounting boss of the fuel injection nozzle. When the exhaust port forming core used during casting is inserted into the cooling water jacket forming core, one end of the exhaust port forming core, which serves as the exhaust port forming portion, is in the cooling water jacket forming core. So that it passes through the mounting boss forming part of the fuel injection nozzle in the
A part of the peripheral surface of the distal end portion to be one exhaust port forming portion of the exhaust port forming core is cut into a planar shape, and after casting, formed by one exhaust port forming portion of the exhaust port forming core. The flat portion formed on a part of the inner peripheral surface of the exhaust port is cut into a curved shape.

A second aspect of the invention is characterized in that the technology of the first aspect of the invention is applied to an intake port. According to a third aspect of the present invention, in addition to the method for manufacturing a cylinder head of a direct injection internal combustion engine according to the first aspect of the present invention, two or three intake valves for each cylinder are substantially orthogonal to a center axis direction of a crankshaft. And two or three intake ports are opened on the side wall surface of the cylinder head as a single intake port where the flow from the throat portion of each port merges on the way. A method for manufacturing a cylinder head of a direct injection internal combustion engine, wherein a cooling water passage is formed between each throat portion of one or three intake ports and a mounting boss of the fuel injection nozzle, and is used during casting. When the intake port forming core is inserted into the cooling water jacket forming core, the leading end of one of the intake port forming cores serving as one of the intake port forming portions is the cooling water jacket forming core. A part of a peripheral surface of a tip portion to be one of the intake port forming portions of the intake port forming core is cut into a flat shape so as to pass through a mounting boss forming portion of the fuel injection nozzle, and after casting, the suction is performed. The flat portion formed on a part of the inner peripheral surface of the intake port formed by the one intake port forming portion of the port forming core is cut into a curved surface shape.

The operation of the present invention will be described. The exhaust port forming core or the intake port forming core can be inserted at right angles to the longitudinal direction of the cylinder with respect to the cooling water jacket forming core. A cooling water passage can be formed between the nozzle and the mounting boss.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the attached drawings. 2 and 3, a cast cylinder head 11 of a direct-injection diesel engine as a direct-injection internal combustion engine has two direct-acting intake valves and two direct-acting intake valves, respectively.
The cylinder head 11 is provided with four exhaust valves (not shown), and four ports (intake ports 12, 13 and exhaust ports 14A, 14A) opened and closed by the four valves.
B) is formed.

The two intake valves and the two exhaust valves of each cylinder are arranged in parallel in a direction substantially perpendicular to the central axis of the crankshaft. The two intake ports 12 and 13 open to one side surface of the cylinder head 11 and communicate with an intake manifold (not shown). Further, the two exhaust ports 14A and 14B
A single exhaust port 14 where the flows from the throat portions A and 14B join in the middle is opened to the other side surface of the cylinder head 11 and communicates with an exhaust manifold (not shown).

On the other hand, a fuel injection nozzle (not shown) is provided upright on a substantially central axis of a cylinder bore of each cylinder of the cylinder head 11, and a mounting boss 1 of the fuel injection nozzle is provided.
5 is integrally formed when the cylinder head 11 is cast.
A cooling water passage 16 is formed between each throat portion of the exhaust ports 14A and 14B and the mounting boss 15 of the fuel injection nozzle.

In FIG. 2, reference numerals 19 and 20 denote intake port forming cores in this embodiment, respectively. Here, in the method of inserting the exhaust port forming core at the time of casting of the cylinder head 11 into the cooling water jacket forming core at a right angle to the cylinder longitudinal direction, the throat portion of the exhaust port and the fuel injection It is difficult to form a cooling water passage between the nozzle and the mounting boss (all parts where the cooling water passage is to be formed are lost due to the insertion trajectory of the port forming core in the recessed port throat). .

Therefore, in the method of manufacturing a cylinder head according to the present invention, referring to FIG. 1, (1) when inserting the exhaust port forming core 17 used for casting into the cooling water jacket forming core, The exhaust port forming part is formed such that the tip part 17A of the one exhaust port 14B forming part of the port forming core 17 passes through the mounting boss forming part 18A of the fuel injection nozzle in the cooling water jacket forming core 18. A part 17a of the peripheral surface of the tip part 17A of the one exhaust port 14B forming part of the child 17 is cut into a planar shape. FIG. 3 shows the insertion trajectory of the exhaust port forming core 17 into the cooling water jacket forming core 18. (2) After casting, the planar shape portion formed on a part of the inner peripheral surface of the exhaust port 14B formed by the one exhaust port 14B forming portion of the exhaust port forming core 17 is shown by oblique lines in FIGS. It is cut into a curved surface shape like the portion 17b.

Thus, the exhaust port forming core 17 is formed.
Can be inserted into the cooling water jacket forming core 18 at a right angle to the longitudinal direction of the cylinder, and the cooling water is inserted between the throat portions of the exhaust ports 14A, 14B and the mounting boss 15 of the fuel injection nozzle. A passage 16 can be formed. In this way, simply by improving the shape of the exhaust port forming core 17, a cooling water passage can be easily formed between the throat portions of the exhaust ports 14A and 14B and the mounting boss 15 of the fuel injection nozzle. Ports 14A, 14B
It is not necessary to reduce the size of each of them, and there is no hindrance to engine performance.

Further, the conventional casting mold of a cylinder head is divided into upper and lower parts to form a cooling water passage around a nozzle holder and a port wall. However, the disadvantage is that burrs are generated on the mating surfaces of the upper and lower molds. Tedious post-processing is needed to remove). Since the cutting in (2) can be performed simultaneously with the processing of the valve seat, there is no particular problem in the manufacturing process, and the productivity is not reduced.

Since the intake ports 12 and 13 have a smaller heat load than the exhaust ports 14A and 14B, there is no need for a cooling water jacket on the upper portion. However, as in the case of the exhaust ports 14A and 14B described above. Thus, a cooling water passage can be formed between the throat portion of the intake port and the mounting boss of the fuel injection nozzle. That is, in this case, two intake valves for each cylinder are arranged in parallel in a direction substantially orthogonal to the direction of the central axis of the crankshaft.
In addition, the two intake ports are opened on the side wall surface of the cylinder head as a single intake port where the flows from the throat portions of each port join on the way, and each throat portion of the two intake ports and the fuel injection nozzle are attached. A cooling water passage is formed between the cooling water passage and the boss.

And, like the exhaust port forming core,
When the intake port forming core used during casting is inserted into the cooling water jacket forming core, one end of the intake port forming core serving as the intake port forming portion has a cooling water jacket forming core. In order to pass through the mounting boss forming portion of the fuel injection nozzle in the above, a part of the peripheral surface of the leading end portion serving as one of the intake port forming portions of the intake port forming core is cut into a planar shape, and after casting, the The flat portion formed on a part of the inner peripheral surface of the intake port formed by the one intake port forming portion of the intake port forming core may be cut into a curved surface shape.

[0020]

According to the first to third aspects of the present invention, in a direct injection type internal combustion engine, a boss for mounting a fuel injection nozzle integrally formed with a cylinder head is advantageous in production cost while using a cast cylinder head. In this case, the cooling water passage around the fuel injection nozzle mounting portion can be easily secured while improving the productivity, and the cooling performance and the durability can be improved. According to the invention, the cooling water passage can be easily formed between the throat portion of the exhaust port and the mounting boss of the fuel injection nozzle, and the exhaust port is advantageous because the heat load is larger than that of the intake port.

[Brief description of the drawings]

FIG. 1 is a partial schematic plan view of a casting core showing one embodiment of a method for manufacturing a cylinder head of a direct injection internal combustion engine according to the present invention.

FIG. 2 is a plan view of a cylinder head of the direct injection internal combustion engine according to the first embodiment;

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Cylinder head 12, 13 Intake port 14A, 14B Exhaust port 14 Exhaust port 15 Boss for mounting fuel injection nozzle 16 Cooling water passage 17 Core for forming exhaust port 18 Core for forming cooling water jacket

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI F02F 1/42 F02F 1/42 B (72) Inventor Hiroshi Murakoshi 66-6 Kamidaiji, Tanajura-cho, Higashishirakawa-gun, Fukushima Pref.

Claims (3)

[Claims] 1. A cylinder head made of casting is provided with two or three intake valves and two exhaust valves for each cylinder, respectively, and the cylinder head is opened and closed by the four or five valves for each cylinder. It has four or five ports for intake and exhaust respectively, and two exhaust valves for each cylinder are arranged in parallel in a direction substantially orthogonal to the central axis direction of the crankshaft. As a single exhaust port where the flow from the throat portion of each port merges on the way, it opens on the side wall surface of the cylinder head, and stands upright on the substantially central axis of the cylinder bore of each cylinder of the cylinder head to form the fuel injection nozzle. The fuel injection nozzle mounting boss is integrally formed with the cylinder head, and a cooling water passage is formed between each throat portion of the two exhaust ports and the fuel injection nozzle mounting boss. A method for manufacturing a cylinder head of a direct injection type internal combustion engine, comprising: inserting an exhaust port forming core used for casting into a cooling water jacket forming core; The periphery of the distal end portion of one of the exhaust port forming cores is such that the distal end portion serving as the port forming portion passes through the mounting boss forming portion of the fuel injection nozzle in the cooling water jacket forming core. A part of the surface is cut into a plane shape, and after casting, a plane shape part formed on a part of the inner peripheral surface of the exhaust port formed by one exhaust port forming part of the exhaust port forming core is cut. A method for manufacturing a cylinder head of a direct injection type internal combustion engine, wherein the cylinder head is processed into a curved surface shape. 2. A cast cylinder head is provided with two or three intake valves and two exhaust valves for each cylinder, and the cylinder head is opened and closed by the four or five valves for each cylinder. It has four or five ports for intake and exhaust respectively, and arranges two or three intake valves for each cylinder in parallel in a direction substantially orthogonal to the central axis direction of the crankshaft; One or three intake ports are opened on the side wall surface of the cylinder head as a single intake port where the flow from the throat portion of each port joins on the way, and stand upright on the substantially central axis of the cylinder bore of each cylinder of the cylinder head. And a boss for mounting the fuel injection nozzle is integrally formed with the cylinder head, and each throat portion of two or three intake ports and the mounting boss for mounting the fuel injection nozzle are provided. A method of manufacturing a cylinder head of a direct injection internal combustion engine, wherein a cooling water passage is formed between the core and a cooling water jacket forming core used at the time of casting. At this time, the suction port forming core is formed such that a tip portion which becomes one of the intake port forming portions of the intake port forming core passes through a mounting boss forming portion of the fuel injection nozzle in the cooling water jacket forming core. A part of a peripheral surface of a tip portion to be one intake port forming portion of the child is cut into a planar shape, and after casting, an inner peripheral surface of the intake port formed by one intake port forming portion of the intake port forming core. A method of manufacturing a cylinder head for a direct injection internal combustion engine, comprising cutting a planar shape portion formed on a part of the cylinder head into a curved surface shape. 3. A method for manufacturing a cylinder head for a direct injection type internal combustion engine according to claim 1, wherein two or three intake valves for each cylinder are arranged in a direction substantially orthogonal to the central axis direction of the crankshaft. The two or three intake ports are arranged in parallel, and two or three intake ports are opened on the side wall surface of the cylinder head as a single intake port where the flow from the throat portion of each port joins on the way. A method of manufacturing a cylinder head of a direct injection internal combustion engine, wherein a cooling water passage is formed between each throat portion of one intake port and a mounting boss of the fuel injection nozzle, the method comprising forming an intake port used during casting. When the service core is inserted into the cooling water jacket forming core, the leading end serving as one of the suction port forming portions of the suction port forming core has fuel injection in the cooling water jacket forming core. A part of a peripheral surface of a tip portion to be one of the intake port forming portions of the intake port forming core is cut into a planar shape so as to pass through a boss forming portion for mounting the chil. A cylinder for a direct-injection type internal combustion engine, wherein a plane shape portion formed on a part of an inner peripheral surface of an intake port formed by one intake port forming portion of a use core is cut into a curved surface shape. Head manufacturing method.