KR102032569B1 - Water jacket structure for cylinder head of dual fuel engine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head of a large engine using dual fuel, and more particularly to a water jacket structure that is formed for cooling a cylinder head block and elements such as an injector installed therein against heat of combustion. The water jacket structure of the cylinder head block for a dual fuel engine of the present invention is mounted on the upper portion of the engine block (2a) to form the upper end of the combustion chamber, the oil fuel injector 120, pilot injector 130 and intake, exhaust valve A water jacket structure formed to circulate the cooling water in the cylinder head block 110 for the dual fuel engine in which the 140 and 150 are installed, and the cooling water circulation passage between the intake port 112 and the exhaust port 114. And an upper passage (116a) through which the pilot injector (130) passes through the passage space; A lower passage (116b) partitioned by a partition (118) below the upper passage (116a) and formed adjacent to the combustion chamber; A portion of the coolant formed through the partition 118 partitioning the upper passage 116a and the lower passage 116b and flowing through the upper passage 116a and the lower passage 116b flows across the partition 118 to be mixed. It has a first through hole 119 to make.

Description

WATER JACKET STRUCTURE FOR CYLINDER HEAD OF DUAL FUEL ENGINE}

The present invention relates to a cylinder head of an engine using dual fuel, and more particularly to a water jacket structure formed for cooling a cylinder head block and elements such as an injector installed therein against heat of combustion.

In gas carriers such as LNG, oil fuel is used to easily use the gas fuel stored in the storage tank as a fuel and to use it as a fuel of a ship propulsion engine without re-liquefying the gas vaporized in the tank. And dual fuel engines that selectively and simultaneously use gas fuel. In addition, large diesel engines used in offshore floatation, offshore structures, or plant power generation facilities using gas such as LNG or LPG have introduced dual fuel engines that can use gaseous fuel together.

Dual fuel engines (diesel engines) include gas fuel operation modes using gas fuel, oil fuel operation modes using oil fuels (eg Marine Diesel Oil, Heavy Fuel Oil, etc.), and gas fuel and oil fuels. Has a mixed operation mode that uses simultaneously.

The oil fuel is injected into the combustion chamber by an oil fuel injector provided in each cylinder head, and the gas fuel is distributed from the main feed pipe to the distribution pipe for each cylinder, and then the amount of gas in the gas admission valve (GAV) assembly. It is regulated and injected through the gas injector into the intake port of the cylinder head.

Unlike the gasoline engine that spark-ignites the fuel by the spark plug, the dual fuel engine is based on a diesel engine that compresses the intake to high temperature and high pressure to self ignition, thereby inducing ignition of gas fuel. A small oil fuel injector is further provided with a pilot pilot (Micro Pilot Injector).

Gas fuels such as natural gas have a low flash point but have a high self ignition temperature of around 550 ° C, so that the pilot is just before the main injection of gas fuel in the gas fuel operation mode. A small amount of pilot oil (eg Marine Diesel Oil, Marine Gas Oil, etc.) is injected through the injector to induce ignition (pilot injection process), thereby achieving stable ignition of the gas fuel.

In addition, even in the oil fuel operation mode, a small amount of pilot oil is injected through the pilot injector immediately before the main fuel is injected to improve the combustion environment of the combustion chamber, thereby improving NOx and improving combustion performance.

FIG. 1A is a view illustrating a cylinder head and a gas supply line of a dual fuel engine developed by the inventors of the present invention, and FIG. 1B is an enlarged view of the cylinder head block and the gas supply line of FIG. 1A.

1A and 1B, in a dual fuel engine, a gas fuel supply line includes a connecting pipe 10 connected to a gas supply line piped from a gas fuel supply source, a connecting pipe 10, and a cylinder head ( And a distribution pipe 30 connected to the cylinder head 2 for each cylinder from the main feed pipe 20.

The cylinder head 2 includes the cylinder head block 40 mounted on the upper part of the engine block 2a, and the cylinder head covers 50 and 60 mounted on the upper part of the cylinder head block 40. As shown in FIG. The cylinder head block 40 forms a combustion chamber in the lower part, and an intake / exhaust valve device and a pilot injector are installed.

The cylinder head covers 50 and 60 cover the upper portion of the cylinder head block 40 and a cam device is installed therein. Although the figure shows the engine of the type provided with the cylinder head covers 50 and 60 of a two-layer structure, there exists an engine of the type which is provided with the cylinder head cover of a single layer structure. In addition, in the case of the single-layer structure, the functions and elements of a part of the cylinder head cover are given to the cylinder head block 40. Accordingly, the cylinder head covers 50 and 60 are separately given two reference numerals in this specification, but they may be one element as well as two elements.

The gas inlet valve assembly 32 is installed at the end of the distribution pipe 30, and the gas inlet valve assembly 32 is mounted on the upper surface of the cylinder head block 40 to adjust the amount of fuel injected into the intake port.

In addition, the coolant distribution pipe 72 is connected from the main coolant pipe 70 to the water jacket inlet on the upper surface of the cylinder head block 40, and an exhaust pipe 80 is connected to one side of the cylinder head block 40.

Since the cylinder head block 40 forms a combustion chamber together with the engine block, the cylinder head block 40 is directly exposed to the heat of combustion, while elements such as oil fuel injectors, pilot injectors, and the like installed therein are also easily heated by the heat of combustion. When various injectors and intake air are heated above the normal temperature, it interferes with normal combustion and makes it difficult to control fuel economy or output.

In order to prevent overheating caused by the heat of combustion, a space portion called a water jacket is formed inside the cylinder head block 40, and cooling is performed by circulating or storing the coolant in the water jacket.

For example, after the engine starts, the engine is operated at the normal operating temperature by circulating the coolant when the normal operating temperature is reached without circulating the coolant before the engine reaches the normal operating temperature.

As such, the water jacket of the cylinder head block must be equipped to cool the heat of combustion. In order to obtain a desired cooling effect, the water jacket needs to be designed in such a way that the cooling water can be circulated smoothly.

Published Patent Publication No. 10-2012-0126756 (Published November 21, 2012) Publication No. 10-2008-0078504 (published Aug. 27, 2008) Registered Patent Publication No. 10-0748734 (2007.08.06. Registration)

Accordingly, an object of the present invention is to provide a water jacket structure of a cylinder head block for a double fuel engine that allows the coolant to circulate smoothly.

In order to achieve the above object, the water jacket structure of the cylinder head block for a dual fuel engine according to the present invention, is mounted on the upper portion of the engine block to form an upper end of the combustion chamber, oil fuel injector, pilot injector and intake, exhaust valve The water jacket structure is formed to circulate the coolant inside the cylinder head block for a dual fuel engine is installed, the upper passage for forming a cooling water circulation passage between the intake port and the exhaust port, the pilot injector passes through the passage space With; A lower passage formed at a lower portion of the upper passage and partitioned by a partition wall and formed adjacent to a combustion chamber; And a first through hole formed to penetrate the partition walls defining the upper passage and the lower passage so that a portion of the cooling water flowing through the upper passage and the lower passage flows across the barrier and is mixed with each other.

In one embodiment, it is preferable that the upper passage has a structure extending in the form of wrapping around the oil fuel injector in addition to the pilot injector.

In this case, it is preferable to further connect the upper passage and the lower portion of the lower passage to allow the coolant to pass through, and to further form a second through hole passing through the lower portion of the oil fuel injector and the pilot injector.

In the water jacket structure of a cylinder head block for a dual fuel engine according to the present invention, the upper surface of the partition wall is perpendicular to the central axis of the first through hole in order to contact the drill tool for drilling the first through hole at a right angle. It is preferable to form a seat surface consisting of a plane of.

In addition, in order to enter the drill tool to the first through hole, it is preferable to form an entry passage on the outer wall of the upper passage of the cylinder head block, and to block the entry passage with the plug after the first through hole is formed.

According to the water jacket structure of the cylinder head block for a dual fuel engine according to the present invention, a portion of the coolant flowing through the upper passage by forming a through hole across the partition wall partitioning the upper passage and the lower passage of the water jacket of the cylinder head block By allowing direct mixing into the lower passages, the cooling water flows smoothly and the cooling effect is prevented from falling by the delay of the cooling water flow, thereby improving the overall cooling performance.

1A is a diagram showing the structure of a dual fuel engine.
1B is an enlarged view of a cylinder head portion of a dual fuel engine.
2 is a perspective view showing a cylinder head block assembly according to the present invention.
3 is a front sectional view of FIG. 2.
4 is a cross-sectional view taken along line AA of FIG. 3.

Hereinafter, an embodiment of a combustion pressure sensor mounting structure of a cylinder head for a dual fuel engine according to the present invention will be described in detail with reference to the accompanying drawings.

2 and 3 show a cylinder head block assembly, FIG. 2 is a perspective view, FIG. 3 is a sectional view, and FIG. 4 is a sectional view taken along the line A-A of FIG.

As shown in FIGS. 2 to 4, the cylinder head block assembly 100 of the dual fuel engine includes a cylinder head block 110 mounted on the engine block. The lower end of the cylinder head block 110 forms an upper end of the combustion chamber, and an intake port 112, an exhaust port 114, and a water jacket 116 are formed.

The cylinder head block 110 includes an oil fuel injector 120 for injecting oil fuel into the combustion chamber, a pilot injector 130 for injecting pilot oil fuel, an intake valve 140 and an exhaust valve 150. It is installed.

In addition, the cylinder head block 110 is provided with an air start valve 160 for forcibly pushing the piston by injecting a high pressure air at the first start.

In addition, the upper surface of the cylinder head block 110, the gas inlet valve 170 provided in the interior of the gas inlet valve assembly 32 (see FIG. 2) connected to the end of the gas fuel distribution pipe 30 (see FIG. 2). ) Is installed. The gas inlet valve 170 includes a control mechanism and a gas injector operated by a control signal of the controller, and discharges gas into the intake port 112 through the nozzle of the gas injector.

The cooling water distribution pipe 72 described above with reference to FIG. 1B flows through the water jacket inlet 116 shown in FIG. 2 to the water jacket formed inside the cylinder head block 110.

As shown in FIGS. 3 and 4, the water jacket formed inside the cylinder head block 110 forms a coolant circulation passage between the intake port 112 and the exhaust port 114, and the pilot injector 130. The upper passage 116a passes through the passage space, and the lower passage 116b is partitioned by the partition wall 118 and formed adjacent to the combustion chamber at the lower portion of the upper passage 116a.

The upper passage 116a and the lower passage 116b are formed in such a way that the upper passage 116a and the lower passage 116b are continuously connected to each other when the casting is made, or the cooling water flows thereafter, or after punching the casting, Through-holes are formed through the upper passage 116a and the lower passage 116b to be connected to each other in a form such that the cooling passages flow in the cooling water flow direction. Accordingly, the coolant entering through the water jacket inlet 116 flows sequentially through the upper passage 116a and the lower passage 116b, and then enters the water jacket on the engine block (or cylinder block) side and circulates or enters the radiator.

In addition, in the present invention, the partition 118 partitioning the upper passage 116a and the lower passage 116b is provided with a first through hole 119 having a very small diameter across. Therefore, a part of the cooling water flowing through the upper passage 116a and the lower passage 116b, which are the main passages, flows across the partition 118 through the first through hole 119 and is mixed with each other.

The first through hole 119 may increase or decrease the number as necessary and does not limit the position.

When all of the coolant flows sequentially through the lower passage 116b after passing through the upper passage 116a, the flow of the cooling water may not be fast and may be heated to a high temperature before reaching the lower passage 116b.

In this case, since the first through hole 119 penetrates through the partition wall 118 that divides the upper passage 116a and the lower passage 116b, a part of the cooling water flowing through the upper passage 116a is directly lowered. Since the mixture enters the passage 116b, it is possible to prepare for the above problem.

In addition, in order to form the first through hole 119 as a drill tool, the drill tool must be entered from the outside, and the edge of the drill tool must contact the surface of the partition wall 118 at right angles so that the drill tool does not slip and the correct ruler is cut. Digging into it.

To this end, a seating surface having a plane perpendicular to the central axis of the first through hole 119 in order to allow the drill tool for drilling the first through hole 119 to contact at right angles on the upper surface of the partition wall 118 ( 118a). The seating surface 118a may be formed when casting the cylinder head block 110.

In addition, an entry passage 119a penetrating the outer wall 118b of the upper passage 116a is formed to enter the drill tool up to the first through hole 119. The entry passage 119a is formed by the plug 119b after the first through hole 119 is formed.

In one embodiment, the upper passage 116a is configured to extend to surround not only the pilot injector 130 but also the oil fuel injector 120 so that the pilot injector 130 and the oil fuel injector 120 are simultaneously. Allowing cooling is desirable for simplicity of structure and weight reduction.

In addition, the main cooling water passage connecting the upper passage 116a and the lower passage 116b is preferably configured in the form of a second through hole 116c as shown in FIG. 3.

The second through hole 116c according to the present embodiment passes through the lower portion of the upper passage 116a and the lower passage 116b, and thus, the main portion of the coolant connecting the upper passage 116a and the lower passage 116b. It acts as a pathway.

The second through hole 116c is preferably formed parallel to the lower surface of the cylinder head block 110, that is, the upper surface of the combustion chamber, so that the drilling depth and the process can be simplified.

In addition, the second through hole 116c may be formed to pass both the lower portion of the oil fuel injector 120 and the lower portion of the pilot injector 130 at the same time.

According to this configuration, the coolant flowing through the upper passage 116a flows into the lower passage 116b through the second through hole 116c, and in the process, lower portions of the oil fuel injector 120 and the pilot injector 130 are removed. At the same time cooling can exert a useful effect. In addition, the second through hole 116c may also have an effect of effectively cooling the lower portion of the cylinder head block 110 adjacent to the combustion chamber.

In the above, certain preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims.

100: cylinder head block assembly
110: cylinder head block
112: intake port
114: exhaust port
116: water jacket
116a: upper passage
116b: lower passage
116c: second through hole
118: bulkhead
118a: seat
118b: outer wall
119: first through hole
119a: entry passage
119b: plug
120: oil fuel injector
130: pilot injector
140: intake valve
150: exhaust valve
160: Air Start Valve
170: gas inlet valve

Claims (5)

It is mounted on the upper part of the engine block (2a) to form the upper end of the combustion chamber, the oil fuel injector 120, the pilot injector 130 and the cylinder head block for dual fuel engine is installed, the intake and exhaust valves (140, 150) As a water jacket structure formed to circulate cooling water inside the 110,
An upper passage 116a which forms a cooling water circulation passage between the intake port 112 and the exhaust port 114 and extends together with the pilot injector 130 so that the oil fuel injector 120 passes through the passage space. and;
A lower passage 116b which is partitioned by a partition 118 at the lower portion of the upper passage 116a and formed adjacent to the combustion chamber;
It is formed through the partition 118 partitioning the upper passage 116a and the lower passage 116b, and a part of the coolant flowing from the upper passage 116a to the lower passage 116b crosses the partition 118 in advance. A first through hole 119 for entering and mixing the lower passage 116b;
The oil fuel injector 120 is connected across the lower portion of the upper passage 116a and the lower passage 116b to provide a main cooling water passage through which cooling water flows from the upper passage 116a to the lower passage 116b. ) And a second through hole 116c passing through the lower portion of the pilot injector 130 is formed;
The first through hole 119 is formed in the upper passage 116a rather than the second through hole 116c so that a part of the first through hole 116c is introduced into the lower passage 116b before cooling water reaches the second through hole 116c. The water jacket structure of the cylinder head block for a double fuel engine is formed at an upstream point and the first through hole 119 is smaller in diameter than the second through hole 116c. delete delete The method of claim 1,
A seating surface 118a formed in a plane perpendicular to the central axis of the first through hole 119 so that a drill tool for drilling the first through hole 119 is perpendicularly contacted with an upper surface of the partition 118. The water jacket structure of the cylinder head block for a dual fuel engine, characterized in that formed. The method of claim 4, wherein
In order to enter the drill tool to the first through hole 119, an entry passage 119a is formed in the outer wall 118b of the upper passage 116a of the cylinder head block 110, and the first through hole 119 is formed. And the entry passage (119a) is blocked by a plug (119b) after forming the water jacket structure of the cylinder head block for a dual fuel engine.

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