JP2005273492A - Sub-chamber internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an indirect injection type internal combustion engine which favorably retains cooling function of a cooling part for a high-temperature part surrounding a sub-chamber and for members attached to a sub-chamber body such as fuel injection valves, ignition plugs or the like, and simplifies the structure of the cooling part, thus reduces the number of working man-hours and working cost. <P>SOLUTION: The ignition flame generated by firing combustion inside the sub-chamber, which is formed inside the sub-chamber body fixed to a cylinder head, is issued into a main combustion chamber of the indirect injection type internal combustion engine, and the gaseous fuel inside the main combustion chamber is combusted. A cooling passage is formed in the interior of the sub-chamber body, directly connected to a cylinder head cooling chamber. Then the cooling water inside the cylinder head cooling chamber is flowed through the cooling passage. Thus, the indirect injection type internal combustion engine is constituted so that the sub-chamber body and/or the members attached to the sub-chamber body can be cooled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is applied to a sub-chamber diesel engine and a sub-chamber gas engine, and main combustion is performed on an ignition flame generated by igniting and burning in a sub-chamber formed inside a sub-chamber body fixed to a cylinder head. The present invention relates to a cooling structure for a sub-chamber internal combustion engine which is jetted into a chamber and combusts gaseous fuel in the main combustion chamber.

  An ignition flame generated by injecting fuel from a fuel injection valve mounted on the sub chamber main body into a sub chamber main body having a sub chamber main body fixed to the cylinder head and having a sub chamber formed therein. Is injected into the main combustion chamber to inject the fuel for ignition in the main combustion chamber, and the fuel gas in the sub chamber formed in the sub chamber main body fixed to the cylinder head is injected into the fuel. In a sub-chamber type gas engine in which a torch ignition flame generated by ignition and combustion by a fuel spray injected from a valve or a spark discharge from an ignition plug is injected into a main combustion chamber to burn gaseous fuel in the main combustion chamber When the mounting member around the sub chamber, particularly the fuel injection valve, becomes hot, the injection hole of the fuel injection valve is clogged with fuel carbides, which tends to induce injection failure of the fuel injection valve. In addition, when the spark plug in the sub-chamber gas engine becomes high in temperature, exhaustion of the discharge part of the spark plug is promoted, and the durability of the spark plug is significantly deteriorated.

When such an injection failure occurs, the required ignition flame cannot be generated in the sub chamber, leading to the occurrence of a combustion failure in the main combustion chamber.
In order to avoid the occurrence of such a problem, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2003-120429), a cooling chamber is formed in the nozzle of the fuel injection valve and provided at the upper part of the nozzle body. A technology that is connected to the cooling water inlet and the cooling water outlet, and cools the high temperature part of the nozzle by passing the cooling water from the cooling water inlet into the cooling chamber, and takes out the cooling water from the cooling water outlet. In addition, a technology is provided in which a cooling chamber is formed in a sub-chamber base that is heated to circulate cooling water in the cooling chamber.

Japanese Patent Laid-Open No. 2003-120429

However, in the technique of forming a cooling chamber in the nozzle of the fuel injection valve and circulating the cooling water as disclosed in Patent Document 1, the cooling effect of the fuel injection valve is great. In order to form a cooling chamber, it is necessary to configure the nozzle in a welded structure, and the structure of the fuel injection valve becomes complicated, requiring a large number of processing steps and increasing the processing cost.
In addition, it is necessary to provide a dedicated cooling water inlet and cooling water outlet in the nozzle body. From this aspect, the structure becomes complicated, and processing of the cooling water inlet and cooling water outlet is required, so that the number of processing steps increases.

  In view of the problems of the prior art, the present invention maintains the cooling function of the cooling part of the mounting part to the high temperature part around the sub chamber and the main body of the sub chamber such as the fuel injection valve and the spark plug, It is an object of the present invention to provide a sub-chamber internal combustion engine having a simplified structure and reduced processing man-hours and processing costs.

The present invention achieves such an object, and is produced by igniting and burning an ignition fuel introduced into a sub chamber formed inside a sub chamber main body fixed to a cylinder head in the sub chamber. In a sub-chamber internal combustion engine in which an ignition flame is jetted into the main combustion chamber to burn the gaseous fuel in the main combustion chamber, a cooling passage that is directly communicated with the cylinder head cooling chamber is formed inside the sub-chamber body, The sub-chamber main body and / or the mounting member to the sub-chamber main body is cooled by causing the cooling water in the cylinder head cooling chamber to flow through the cooling passage.
Here, the fuel for ignition is petroleum fuel (kerosene, light oil, gasoline, heavy oil (A, B, C)), alcohol fuel (methanol), DME (dimethyl ether), GTL fuel (natural gas is decomposed and synthesized) Synthetic oils that are made in this way, including kerosene, light oil, and gasoline equivalents).
In addition, the gaseous fuel contains or contains combustible components such as methane, ethane, propane, butane, hydrogen, carbon monoxide (more specifically, natural gas, city gas containing methane as the main component). (13A, 12A)), propane gas mainly containing propane or butane, coal gas containing hydrogen, digestion gas containing methane and carbon monoxide, biogas, and the like.

  The present invention also includes a sub chamber main body fixed to the cylinder head and having a fuel injection valve mounted therein and a sub chamber formed therein, and fuel is injected from the fuel injection valve into the air in the sub chamber. This is applied to a sub-chamber type diesel engine in which the ignition flame generated by this is ejected into the main combustion chamber and the ignition fuel in the main combustion chamber is combusted, and is directly communicated with the cylinder head cooling chamber inside the sub chamber main body. A cooling passage is formed, and the sub-chamber body and the fuel injection valve are cooled by flowing cooling water in the cylinder head cooling chamber through the cooling passage.

  Further, the present invention is produced by igniting and burning gaseous fuel in the sub chamber formed inside the sub chamber main body fixed to the cylinder head by fuel spray injected from the fuel injection valve or spark discharge from the spark plug. This is applied to a sub-chamber type gas engine in which a torch ignition flame is jetted into the main combustion chamber to burn the gaseous fuel in the main combustion chamber, and a cooling passage directly communicating with the cylinder head cooling chamber is formed inside the sub-chamber body. The sub-chamber main body and the fuel injection valve or the spark plug are cooled by flowing cooling water in the cylinder head cooling chamber through the cooling passage.

  According to this invention, the cooling passage directly communicating with the cylinder head cooling chamber is formed inside the sub chamber main body fixed to the cylinder head, and the cooling water in the cylinder head cooling chamber is cooled in the cylinder head cooling chamber. The cooling passage is caused to flow by the flow energy of water to cool the high temperature portion of the sub chamber main body, and the mounting member to the sub chamber main body, that is, the fuel injection valve in the sub chamber diesel engine is cooled, In the sub-chamber type gas engine, it becomes possible to cool the fuel injection valve or spark plug for torch ignition.

Therefore, according to such an invention, the high temperature of the sub chamber main body can be obtained with an apparatus having a very simple structure and a small number of processing steps, in which a cooling passage directly communicating with the cylinder head cooling chamber is processed inside the sub chamber main body. And the mounting member to the sub chamber main body (that is, the fuel injection valve in the sub chamber type diesel engine and the fuel injection valve or spark plug for torch ignition in the sub chamber type gas engine) can be cooled at the same time. it can.
Further, the high temperature portion of the sub chamber main body and the mounting member to the sub chamber main body can be obtained simply by passing the cooling water through the cooling passage processed in the sub chamber main body by the flow energy of the cooling water in the cylinder head cooling chamber. Since cooling is possible, it is not necessary to provide a cooling water inlet / outlet for cooling the sub-chamber main body and the mounting member to the sub-chamber main body in the cylinder head as in the prior art. The structure becomes simple.
Thereby, the processing man-hour and processing cost of the cooling structure of the sub chamber main body and the mounting member to the sub chamber main body can be reduced.

In the present invention, preferably, the cooling passage is constituted by a straight cooling hole which is drilled through the sub chamber main body on both sides of the axis of the sub chamber main body.
If comprised in this way, since a cooling channel | path can be formed by penetrating a straight cooling hole in a subchamber main body, the process of a cooling channel | path becomes easy.
Further, the cooling holes are provided in a plurality of stages in the axial direction of the sub chamber main body, or the cooling passages are drilled through the sub chamber main body so as to cross each other in a plane perpendicular to the axis of the sub chamber and not to communicate with each other. If constituted by a plurality of straight cooling holes, the cooling effect of the sub chamber main body and the mounting member to the sub chamber main body can be further improved by the simple processing as described above.

Preferably, in this invention, the sub chamber main body is fixed to the cylinder head and has a holder portion in which either a fuel injection valve or a spark plug is mounted, and is connected to the holder portion so as to be inside the sub chamber. And a connecting portion side of the holder portion to the base portion is exposed in the cylinder head cooling chamber, and the cooling passage is formed through the holder portion. The first cooling hole and the second cooling hole formed through the base part are configured.
If comprised in this way, in addition to cooling by the 1st cooling hole of a holder part and the fuel injection valve or spark plug in this holder part, a high-temperature nozzle | cap | die part can be cooled by a 2nd cooling hole, Therefore The entire component can be effectively cooled, and the durability of the component is improved.

In the present invention, preferably, the cooling passage is configured by a plurality of cooling fins formed in an exposed portion of the outer periphery of the sub chamber main body into the cylinder head cooling chamber, and the cooling water in the cylinder head cooling chamber is supplied to the cooling chamber. By passing between the cooling fins, the sub chamber main body and / or the mounting member to the sub chamber main body are cooled via the cooling fin.
If comprised in this way, since a subchamber main body and the mounting member to this subchamber main body are cooled by heat exchange with the cooling water in a cylinder head cooling chamber by the several cooling fin formed in the subchamber main body outer periphery, heat exchange Thus, the cooling effect of the sub chamber main body and the mounting member to the sub chamber main body is further improved.

As described above, according to the present invention, the cooling passage is made to flow by the flow energy of the cooling water in the cylinder head cooling chamber to cool the high temperature portion of the sub chamber main body and to attach the sub member main body to the sub chamber main body. It is possible to cool the fuel injection valve in the chamber type diesel engine and the fuel injection valve or spark plug for torch ignition in the sub chamber type gas engine, and directly into the cylinder head cooling chamber inside the sub chamber main body. Both the high temperature portion of the sub chamber main body and the mounting member to the sub chamber main body can be cooled at the same time with an apparatus having an extremely simple structure and a small number of processing steps for processing the cooling passage communicated. .
Further, since there is no need to provide the sub-chamber main body and the cooling water inlet / outlet for cooling the mounting member to the sub-chamber main body as in the prior art, the structure can be simplified from this aspect as compared with the prior art. .
Thereby, the processing man-hour and processing cost of the cooling structure of the sub chamber main body and the mounting member to the sub chamber main body can be reduced.

  Hereinafter, the present invention will be described in detail using embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.

  1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a cross-sectional view taken along a sub-chamber axial center line around a sub-chamber in a sub-chamber diesel engine, and FIG. FIG. 2A and 2B show a second embodiment, in which FIG. 2A is a partial cross-sectional view of a tip portion of an injection valve holder, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 3A and 3B show a third embodiment, in which FIG. 3A is a partial cross-sectional view of a tip portion of an injection valve holder, and FIG. 3B is a cross-sectional view taken along line CC in FIG. 4A and 4B show a fourth embodiment, in which FIG. 4A is a partial cross-sectional view of a tip portion of an injection valve holder, and FIG. 4B is a cross-sectional view taken along line DD in FIG.

In FIGS. 1A and 1B showing the first embodiment of the present invention, 5 is a cylinder head, 8 is a cylinder head cooling chamber formed in the cylinder head 5, and cooling water flows through the inside. The cylinder head 5 is cooled. An injection valve holder 1 is fitted and fixed in a mounting hole 5 a formed in the cylinder head 5, and a fuel injection valve 2 is fixed at the center of the injection valve holder 1. Reference numeral 9 denotes an O-ring for sealing a cooling water fitted on the outer periphery of the injection valve holder 1.
Reference numeral 3 denotes a sub-chamber base connected to the end of the injection valve holder 1. The gasket 12 is fixed by tightening the injection valve holder 1 with a fixing bolt (not shown) for fixing the injection valve holder 1. It is fastened and fixed to the cylinder head 5.

Reference numeral 4 denotes a sub chamber formed in the sub chamber base 3. The fuel injected from the nozzle tip 2a of the fuel injection valve 2 into the sub chamber 4 is ignited and combusted. The sub chamber 4 communicates with the main combustion chamber 7 through a plurality of communication holes 6.
Reference numeral 10 denotes a cooling hole drilled in a portion exposed in the cylinder head cooling chamber 8 of the injection valve holder 1. The cooling hole 10 is a straight hole that is formed in both sides of the shaft center 1 a of the injection valve holder 1 so as to penetrate the injection valve holder 1 in a substantially parallel manner, and opens directly into the cylinder head cooling chamber 8. ing.
Reference numeral 20 denotes a cooling hole formed through the sub-chamber base 3, which is drilled on both sides of the shaft center 1 a of the injection valve holder 1 and directly opens into the cylinder head cooling chamber 8.
About this cooling hole 20, it is also omissible as needed.

  During the operation of the sub chamber type diesel engine, the compressed air in the main combustion chamber 7 is filled into the sub chamber 4 through the communication hole 6 during the compression stroke, and the fuel injection valve 2 is set at the set injection timing. The fuel is injected from the nozzle tip 2a into the pressurized air in the sub chamber 4 and ignited and combusted, and the ignition flame generated thereby is injected into the main combustion chamber 7 through the communication hole 6. Thus, the pressurized air in the main combustion chamber 7 is ignited and burned.

Further, during the operation of the sub-chamber type diesel engine, the cooling water flowing in the cylinder head cooling chamber 8 cools the high temperature portion of the cylinder head 5 and the injection valve holder by the flow energy of the cooling water. 1, the fuel injection valve 2, particularly the nozzle tip 2 a of the fuel injection valve 2 is passed through the exposed portion of the injection valve holder 1 into the cylinder head cooling chamber 8. Cooling.
As a result, the fuel injection valve 2 is sufficiently cooled and its temperature rise is suppressed, and it is possible to avoid clogging due to fuel carbide in the nozzle hole of the nozzle tip 2a as the temperature of the fuel injection valve 2 increases. In addition, it is possible to prevent the occurrence of injection failure of the fuel injection valve.

  Therefore, according to the first embodiment, since the cooling hole 10 directly communicating with the cylinder head cooling chamber 8 is formed in the injection valve holder 1 fixed to the cylinder head 5, the inside of the cylinder head cooling chamber 8 is formed. The cooling water is caused to flow through the cooling hole 10 by the flow energy of the cooling water in the cylinder head cooling chamber 8 to cool the high temperature portion of the injection valve holder 1 and the fuel attached to the injection valve holder 1. The injection valve 2 can be cooled.

As a result, the injection valve holder 1 is machined with a very simple structure and a small number of processing steps, such as machining the straight cooling hole 10 directly communicating with the cylinder head cooling chamber 8 inside the injection valve holder 1. Both the high temperature part 1 and the fuel injection valve 2 can be cooled simultaneously.
Further, only by flowing the cooling water into the cooling hole 10 machined inside the injection valve holder 1 by the flow energy of the cooling water in the cylinder head cooling chamber 8, the high temperature portion of the injection valve holder 1 and the fuel injection Since the valve 2 can be cooled, it is not necessary to provide the high temperature portion of the injection valve holder 1 and the cooling water inlet / outlet for cooling the fuel injection valve 2 on the cylinder head side, and the structure is simplified from this aspect.
Further, in addition to the cooling of the high temperature portion of the injection valve holder 1 and the fuel injection valve 2 as described above, the high temperature sub-chamber base 3 is cooled by the cooling water flowing through the cooling hole (second cooling hole) 20. If comprised so, the whole structural member around the subchamber 4 can be cooled effectively, and durability of this structural member will improve.

In the second embodiment shown in FIGS. 2 (A) and 2 (B), a straight shape that is directly communicated with the cylinder head cooling chamber 8 inside the injection valve holder 1 is the same as in the first embodiment. Two cooling holes 10 are provided in the axial direction of the injection valve holder 1 (or three or more stages).
With this configuration, as in the first embodiment, a simple cooling hole 10 that directly communicates with the cylinder head cooling chamber 8 is drilled inside the injection valve holder 1. Further, the cooling effect of the high temperature portion of the injection valve holder 1 and the fuel injection valve 2 can be further improved as compared with the first embodiment.

In the third embodiment shown in FIGS. 3A and 3B, the injection valve holder 1 has a plurality of straight cooling holes 10 communicating directly with the cylinder head cooling chamber 8. The injection valve holder 1 is perforated so as to cross each other in a plane perpendicular to the axis of the holder 1 and not to communicate with each other.
If comprised in this way, the high temperature of the injection valve holder 1 will be carried out by the simple process of drilling a plurality of straight cooling holes 10 directly communicating with the cylinder head cooling chamber 8 inside the injection valve holder 1. The cooling effect of the part and the fuel injection valve 2 can be further improved as compared with the first embodiment.

In the fourth embodiment shown in FIGS. 4 (A) and 4 (B), a plurality of portions along the axial direction of the injection valve holder 1 are disposed at portions exposed in the cylinder head cooling chamber 8 of the injection valve holder 1. The cooling fins 15 are formed, and the cooling water in the cylinder head cooling chamber 8 is passed between the cooling fins 15 so that the high-temperature portion of the injection valve holder 1 and the fuel injection valve 2 pass through the cooling fins 15. Is configured to cool.
According to the fourth embodiment, since the high temperature portion of the injection valve holder 1 and the fuel injection valve 2 are cooled by heat exchange with the cooling water in the cylinder head cooling chamber 8 by the cooling fins 15, the heat exchange is transferred. The heat area is increased, and the cooling effect of the high temperature portion of the injection valve holder 1 and the fuel injection valve 2 is further improved.

In the above embodiment, the present invention is applied to the sub-chamber diesel engine. However, the present invention is applied to the inside of the sub-chamber main body (corresponding to the injection valve holder 1 in the above embodiment) fixed to the cylinder head 5. The torch ignition flame generated by igniting and burning the gaseous fuel in the sub chamber 4 formed by the fuel spray injected from the fuel injection valve or the spark discharge from the spark plug is injected into the main combustion chamber 7. The present invention can also be applied to a sub-chamber type gas engine configured to combust gas fuel in the main combustion chamber 7.
In this case, the cooling hole 10 is provided in the sub chamber main body (corresponding to the injection valve holder 1) as in the first to third embodiments, or the sub chamber main body (injection valve holder 1) as in the fourth embodiment. A plurality of cooling fins 15 are formed in a portion exposed in the cylinder head cooling chamber 8) to cool the high temperature portion of the sub chamber main body and the fuel injection valve or spark plug mounted in the sub chamber main body.

  According to the present invention, the structure of the cooling unit can be simplified while maintaining the cooling function of the cooling unit of the high temperature portion around the sub chamber and the auxiliary chamber main body such as the fuel injection valve and the spark plug. It is possible to provide a sub-chamber diesel engine and a sub-chamber internal combustion engine with reduced processing man-hours and processing costs.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a first embodiment of the present invention, wherein (A) is a cross-sectional view taken along a sub-chamber axial center line around a sub-chamber in a sub-chamber diesel engine, and (B) is a cross-sectional view taken along line AA in (A). . A 2nd Example is shown, (A) is a fragmentary sectional view of a tip part of an injection valve holder, and (B) is a BB line sectional view in (A). (A) is a fragmentary sectional view of an injection valve holder front-end | tip part, (B) is CC sectional view taken on the line in (A). (A) is a fragmentary sectional view of a tip part of an injection valve holder, and (B) is a DD line sectional view in (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection valve holder 2 Fuel injection valve 2a Nozzle tip 3 Subchamber cap 4 Subchamber 5 Cylinder head 6 Communication hole 7 Main combustion chamber 8 Cylinder head cooling chamber 10 Cooling hole 15 Cooling fin 20 Cooling hole of subchamber cap

Claims (8)

  An ignition flame generated by igniting and burning the ignition fuel introduced into the sub chamber formed inside the sub chamber main body fixed to the cylinder head is injected into the main combustion chamber In the sub-chamber internal combustion engine that burns gaseous fuel in the main combustion chamber, a cooling passage that is directly communicated with the cylinder head cooling chamber is formed inside the sub-chamber body, and cooling water in the cylinder head cooling chamber is supplied to the cooling passage. A sub-chamber internal combustion engine configured to cool the sub-chamber main body and a member attached to the sub-chamber main body by flowing the sub-chamber.   2. The sub-chamber internal combustion engine according to claim 1, wherein the cooling passage is configured by a straight cooling hole drilled through the sub-chamber body on both sides of the axis of the sub-chamber body. .   The sub-chamber internal combustion engine according to claim 2, wherein the cooling hole is provided in a plurality of stages in the axial direction of the sub-chamber body.   The cooling passage is constituted by a plurality of straight cooling holes that are perforated through the sub chamber main body so as to cross each other in a plane perpendicular to the axis of the sub chamber main body and not to communicate with each other. 2. The sub-chamber internal combustion engine according to claim 1, wherein   The sub-chamber main body is fixed to the cylinder head by a holder portion in which either a fuel injection valve or a spark plug is mounted, and a base portion connected to the holder portion to form the sub-chamber therein. A first cooling hole formed by penetrating the holder portion, the connecting portion side of the holder portion connected to the base portion being exposed in the cylinder head cooling chamber. 2. The sub-chamber internal combustion engine according to claim 1, wherein the sub-chamber internal combustion engine is constituted by a second cooling hole formed so as to penetrate through the base portion.   The cooling passage is constituted by a plurality of cooling fins formed on the outer periphery of the sub chamber main body and exposed to the cylinder head cooling chamber, and the cooling water in the cylinder head cooling chamber is passed between the cooling fins. 2. A sub-chamber internal combustion engine according to claim 1, wherein the sub-chamber main body and / or a member attached to the sub-chamber main body is cooled via the cooling fin.   An ignition flame generated by injecting fuel from a fuel injection valve mounted on the sub chamber main body into a sub chamber main body having a sub chamber main body fixed to the cylinder head and having a sub chamber formed therein. In the sub-combustion type diesel engine in which the fuel for ignition in the main combustion chamber is combusted to form a cooling passage directly communicating with the cylinder head cooling chamber in the sub-chamber body, A sub-chamber type diesel engine configured to cool the sub-chamber body and the fuel injection valve by causing cooling water in a cylinder head cooling chamber to flow through the cooling passage.   A torch produced by igniting and burning a fuel for ignition injected from a fuel injection valve by a fuel injection valve or a spark discharge from a spark plug formed in the sub chamber main body fixed to the cylinder head In a sub-chamber type gas engine in which an ignition flame is jetted into the main combustion chamber to burn the gaseous fuel in the main combustion chamber, a cooling passage is formed in the sub-chamber body and communicates directly with the cylinder head cooling chamber, A sub-chamber type gas engine configured to cool the sub-chamber main body and the fuel injection valve or the spark plug by flowing cooling water in a cylinder head cooling chamber through the cooling passage.

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