JP4559503B2 - Fuel injection valve cooling system - Google Patents

Description

  The present invention relates to a cooling device for a fuel injection valve used in an internal combustion engine such as a gas engine.

  Conventionally, as a gas engine, an air-fuel mixture (a gas in which a gas fuel such as city gas and air is mixed in an appropriate ratio before being introduced into the combustion chamber) is supplied into the main combustion chamber, and a small amount of heavy oil or light oil is supplied. There is a gas engine in which liquid fuel is injected to ignite and burn the mixture. In some cases, a sub-chamber called a pre-combustion chamber or the like into which the liquid fuel is injected is installed. In this case, the air-fuel mixture in the main combustion chamber is introduced into the sub-chamber communicated with the main combustion chamber. A part is introduced, and a liquid fuel such as a minute amount of heavy oil or light oil is injected into the sub-chamber in that state, and the mixture is ignited and burned. Both types of gas engines are called micropilot gas engines.

  As a fuel injection valve of a gas engine used for a micropilot type gas engine having such a sub chamber, there is a “fuel injection valve mounting structure” disclosed in Japanese Patent Laid-Open No. 2003-254195 (Patent Document 1). . FIG. 5 shows a cross section of the fuel injection valve mounting structure in the gas engine disclosed in Patent Document 1. In FIG. 5, 1 is a cylinder head, 2 is a cooling water chamber in the cylinder head 1, 3 is a fuel injection valve, 4 is a main combustion chamber, 5 is a lower sub-chamber base, 6 is an upper sub-chamber base, and 7 is a lower part A sub-chamber formed inside the sub-chamber base 5 and the upper sub-chamber base 6, 8 is a communication hole for communicating the main combustion chamber 4 and the sub-chamber 7, and 9 is a glow plug for preheating at start-up. Further, the fuel injection valve 3 includes a nozzle tip 10, a plurality of nozzle holes (not shown) perforated at the tip of the nozzle tip 10, a needle valve 12 fitted in the nozzle tip 10 so as to be slidable back and forth, It consists of a nozzle nut 13 and a nozzle body 14.

  During operation of the gas engine, pilot liquid fuel is injected from the injection hole of the fuel injection valve 3 into the gas introduced into the sub chamber 7 through the communication hole 8 at a predetermined injection timing, and ignition occurs in the sub chamber 7. Combustion is performed, and the vicinity of the tip of the nozzle tip 10 of the fuel injection valve 3 is heated to a high temperature. Here, the nozzle tip 10 has a sheet portion with the upper sub chamber base 6 in the vicinity of the tip thereof formed in a conical surface, and the nozzle side sheet surface and the base side sheet surface are in direct contact with each other in a fluid-tight manner, The upper sub-chamber base 6 is fastened and fixed by a fastening force of a fuel injection valve fastening bolt (not shown). Therefore, the heat of the nozzle tip 10 heated to a high temperature is transmitted to the upper sub chamber base 6 through the sheet portion, and further, the cooling water chamber 2 provided in the cylinder head 1 from the outer surface of the upper sub chamber base 6. It is transmitted to the cooling water inside. Thus, the nozzle tip 10 is cooled.

  By the way, in the cooling water system of the fuel injection valve 3 in such a fuel injection valve mounting structure, there is no outlet pipe for the fuel injection valve cooling water, and the fuel injection valve 3 is cooled by natural convection of the cooling water. Therefore, there is a problem that a high cooling effect of the fuel injection valve 3 cannot be obtained. Further, as described above, there is no outlet pipe for the fuel injection valve cooling water, and the cooling water that has cooled the fuel injection valve 3 merges with the cooling water that has cooled other than the fuel injection valve 3 at the center in the cylinder head 1. ing. For this reason, there is a problem that the state of the cooling water (for example, the water temperature) immediately after cooling the fuel injection valve 3 cannot be measured.

  Therefore, in order to solve the above-described problem of fuel injection valve cooling by natural convection, the “cooling device for pilot fuel injection valve for gas engine” disclosed in Japanese Patent Application Laid-Open No. 2007-205295 (Patent Document 2) is disclosed. Thus, a method of cooling the fuel injection valve by forced convection has been proposed. FIG. 6 schematically shows a “cooling device for a pilot fuel injection valve for a gas engine” disclosed in Patent Document 2, and is a cross section of a portion of cylinder # 1 among six cylinders # 1 to # 6. Indicates.

  In FIG. 6, a mounting hole 23 for the fuel injection valve 22 is formed in the cylinder head 21, and a cooling jacket 25 and an annular chamber 26 are provided between the inner peripheral surface of the mounting hole 23 and the outer peripheral surface of the valve holder 24. And the cooling jacket 25 extends in the axial direction of the valve holder 24, that is, in the axial direction of the fuel injection valve 22, and communicates with the branch path 28 from the cooling water path 27 in the cylinder head 21. is doing. As described above, the cooling jacket 25 cools the fuel injection valve 22 via the valve holder 24.

  An annular portion 30 is formed at the distal end portion of the valve holder 24 so as to surround the distal end portion of the nozzle body 29 of the fuel injection valve 22. A valve holder cooling passage 31 a that communicates the lower end of the cooling jacket 25 and the annular portion 30 and a valve holder cooling passage 31 b that communicates the annular portion 30 and the annular chamber 26 are formed.

  Further, an internal connection path 32 extending outward from the annular chamber 26 is formed in the cylinder head 21, and the internal connection path 32 is connected via a connection branch pipe 33 attached to the outside of the cylinder head 21. The valve holder cooling water collecting pipe 34 is connected. Further, connecting branch pipes 33 extending from the annular chambers 26 of the other cylinders # 2 to # 6 via the internal connection path 32 are also connected to the valve holder cooling water collecting pipe 34, respectively.

  On the other hand, the upper end of the cooling jacket 25 communicates with the upper cylinder head cooling chamber 35, and the cylinder head cooling chamber 35 is connected to a cylinder outlet branch pipe 36. Further, the cylinder outlet branch pipes 36 from the respective cylinders # 1 to # 6 are commonly connected to the cooling water outlet main pipe 37. A cooling water engine inlet 20a of the cooling water passage 27 and a cooling water engine outlet 20b of the cooling water outlet main pipe 37 are provided with a cooler (not shown) and a pump 38 for cooling the cooling water. These are connected by an external cooling path 39 arranged outside the gas engine 20. Thus, the cooling water cooled by the cooler enters the gas engine 20 from the cooling water engine inlet 20a, and enters the cooling water passage 27, branch passage 28, cooling jacket 25, cylinder head cooling chamber 35, cylinder outlet branch pipe 36. And is forcedly circulated by the pump 38 so as to pass through the cooling water outlet main pipe 37, exit from the gas engine 20 through the cooling water engine outlet 20b, and return to the cooler.

  Furthermore, an orifice 40 is interposed between the cooling water engine outlet 20b of the cooling water outlet main pipe 37 in the external cooling passage 39 and the cooler. By restricting the flow rate of the cooling water flowing in the external cooling passage 39 by the orifice 40, the internal pressure of the external cooling passage 39 on the downstream side of the orifice 40 is kept lower than the internal pressure of the cooling passage in the gas engine 20. .

  The valve holder cooling water collecting pipe 34 is connected to an external connecting pipe 41 arranged outside the gas engine 20, and the external connecting pipe 41 is connected between the orifice 40 in the external cooling path 39 and the cooler. Has been. That is, the external connection pipe 41 is connected to the low pressure part provided in the above-mentioned cooling water circulation path.

  In the cooling device for the fuel injection valve 22, the valve holder cooling path 31 a is the cooling jacket 25 among the valve holder cooling path 31 a and the valve holder cooling path 31 b communicating with the annular portion 30 formed in the distal end portion of the valve holder 24. On the other hand, the valve holder cooling passage 31 b is connected to the low pressure portion downstream of the orifice 40 through the annular chamber 26, the internal connection passage 32, the connection branch pipe 33 and the external connection pipe 41. Accordingly, a pressure difference is generated between the connection end of the cooling jacket 25 and the connection end of the annular chamber 26 in the valve holder cooling path 31a and the valve holder cooling path 31b sandwiching the annular portion 30. As a result, a part of the cooling water flowing in the cooling water passage 27 flows in from one end of the valve holder cooling passage 31a and is forced out of the other end of the valve holder cooling passage 31b through the annular portion 30. It will be washed away.

  Therefore, the temperature of the tip portion of the nozzle body 29 can be greatly improved as compared with the cooling of the fuel injection valve by natural convection as in the “fuel injection valve mounting structure” disclosed in Patent Document 1.

  However, the “cooling device for pilot fuel injection valve for gas engine” disclosed in the above-mentioned conventional Patent Document 2 has the following problems.

  That is, in the cooling device for the pilot fuel injection valve for the gas engine, the valve holder cooling path 31a and the valve holder cooling path 31b are provided in the valve holder 24. Therefore, when forming the valve holder cooling passages 31a and 31b, it is necessary to form a hole at the tip of the valve holder 24 so as to reach the annular portion 30 by direct drilling or the like. There is a limit to securing a water channel that can supply a cooling amount of cooling water. Therefore, there is a problem that a higher cooling effect cannot be obtained.

Furthermore, a pressure difference is generated between the connection end of the cooling jacket 25 and the connection end of the annular chamber 26 in each of the valve holder cooling passages 31a and the valve holder cooling passages 31b of the six cylinders # 1 to # 6. The orifice 40 is provided in an external cooling path 39 to which cylinder outlet branch pipes 36 from the cylinders # 1 to # 6 are connected in common via a cooling water outlet main pipe 37. Therefore, for example, based on the cooling water temperature in each cylinder outlet branch pipe 36, it flows in from one end of the valve holder cooling path 31a of each cylinder # 1 to # 6, and passes through the annular part 30 to If adjustment of the cooling water for each of the cylinders # 1 to # 6 cannot be performed independently of each other, such as adjusting the flow rate of the cooling water flowing out from the other end independently of each of the cylinders # 1 to # 6 There is also a problem to say.
Japanese Patent Laid-Open No. 2003-254195 JP 2007-205295 A

  Accordingly, an object of the present invention is to provide a fuel injection valve cooling device that can obtain a further high cooling effect of the fuel injection valve and can adjust the cooling water of each cylinder independently of each other. is there.

In order to solve the above problems, a cooling device for a fuel injection valve according to the present invention comprises:
A fuel injection valve attached to a cylinder head of the internal combustion engine via a valve holder and supplying fuel to the combustion chamber of the internal combustion engine;
A cooling water supply passage for supplying cooling water into the cylinder head; a cooling jacket for passing the cooling water around the valve holder; and cooling water after passing through the cooling jacket from the cylinder head to the cylinder head An engine cooling path that forcibly flows cooling water from the cooling water supply path to the cooling water discharge path.
An annular cooling portion provided at a tip portion in the valve holder so as to surround the tip portion of the fuel injection valve, and in which cooling water for cooling the tip portion of the fuel injection valve is circulated;
A first valve holder cooling path for communicating the annular cooling portion provided in the valve holder to a location where the pressure is lower than the cooling jacket in the engine cooling path;
A second valve holder cooling passage that communicates the annular cooling portion provided in the valve holder with the cooling jacket;
The valve holder includes a first valve holder to which the tip of the fuel injection valve is closely attached and a second valve holder to which the tip of the first valve holder is closely attached,
The annular cooling section, the first valve holder cooling path, and the second valve holder cooling path are grooves formed by plane machining on one of the outer peripheral surface of the first valve holder and the inner peripheral surface of the second valve holder. Alternatively, the concave portion is formed by closing the concave portion with the other.

  According to the above configuration, the cooling water supplied from the cooling water supply passage into the cylinder head passes around the valve holder by the cooling jacket and cools the fuel injection valve via the valve holder. Then, the cooling water that has passed through the cooling jacket is guided from the inside of the cylinder head to the outside of the cylinder head by the cooling water discharge passage. At that time, since the cooling water is forced to flow from the cooling water supply passage to the cooling water discharge passage, a pressure difference is generated between the upstream side and the downstream side of the fuel injection valve.

  An annular cooling section provided in the valve holder is communicated with the cooling jacket by a second valve holder cooling path, while the annular cooling section is connected to the cooling jacket in the engine cooling path by the first valve holder cooling path. Is also communicated to a location where the pressure is low. Therefore, a pressure difference is generated between the communication position of the annular cooling section with the cooling jacket and the communication position of the annular cooling section with a location where the pressure is lower than that of the cooling jacket. The part is taken into the annular cooling part and circulates in the annular cooling part provided in the valve holder to cool the tip of the fuel injection valve. Thus, the cooling water that has cooled the tip of the fuel injection valve flows out to a location where the pressure is lower than that of the cooling jacket.

  At that time, by utilizing a pressure difference generated between the upstream side and the downstream side of the fuel injection valve, a part of the cooling water in the cooling jacket is taken into the annular cooling part, and the tip part of the fuel injection valve Therefore, a dedicated pump for forcibly introducing cooling water is not required, and the tip of the fuel injection valve can be effectively cooled with a simple configuration and at a low cost.

Further, the annular cooling section, the first valve holder cooling path and the second valve holder cooling path are flat on any one of the outer peripheral surface of the first valve holder and the inner peripheral surface of the second valve holder constituting the valve holder. It is formed by closing a groove or a recess formed by processing on the other side. Therefore, the annular cooling section, the first valve holder cooling path, and the first valve holder cooling path can be obtained simply by forming the groove or the concave portion by plane machining on one of the outer peripheral surface of the first valve holder and the inner peripheral surface of the second valve holder. The second valve holder cooling path can be formed, and a groove or a recess having a sufficient area can be secured with respect to the outer peripheral surface of the first valve holder or the inner peripheral surface of the second valve holder. That is, it is possible to easily create a cooling water channel capable of obtaining a high cooling effect.

In the fuel injection valve cooling device according to the embodiment,
The fuel injection valve, the cooling jacket, the annular cooling section, the first valve holder cooling path and the second valve holder cooling path are provided for each cylinder of the internal combustion engine,
For each cylinder above,
A cylinder outlet branch pipe that connects the cooling jacket and the cooling water discharge passage and is provided with a throttle means;
A connecting branch pipe that connects the first valve holder cooling passage and the downstream side of the throttle means in the cylinder outlet branch pipe.

  According to this embodiment, the throttle means is interposed in the cylinder outlet branch pipe connecting the cooling jacket and the cooling water discharge passage, and more than the throttle means in the first valve holder cooling path and the cylinder outlet branch pipe. The downstream side is connected with a connecting branch pipe. Therefore, it is possible to positively provide a pressure difference between the cooling jacket and the first valve holder cooling path, and to forcibly take cooling water into the annular cooling portion.

  Further, since the throttle means is provided in the cylinder outlet branch pipe for each cylinder of the internal combustion engine, the temperature and flow rate of the cooling water in the cylinder outlet branch pipe can be measured for each cylinder. For example, it is possible to easily change the state of the cooling water in each cylinder independently of each other by adjusting the degree of throttling of the throttling means for each cylinder.

In the fuel injection valve cooling device according to the embodiment,
The throttle means provided in the cylinder outlet branch pipe is an orifice.

  According to this embodiment, the throttle means can be easily realized by an orifice.

  As is apparent from the above, the fuel injection valve cooling device according to the present invention cools from the cooling water supply passage to the cooling water discharge passage in an engine cooling passage including a cooling water supply passage, a cooling jacket, and a cooling water discharge passage. Since water is forced to flow, a pressure difference is generated between the upstream side and the downstream side of the fuel injection valve. And while the annular cooling part provided in the valve holder is communicated with the cooling jacket by the second valve holder cooling path, the annular cooling part is more than the cooling jacket in the engine cooling path by the first valve holder cooling path. Since the pressure is communicated to a location where the pressure is low, a pressure difference occurs between the communication position of the annular cooling portion with the cooling jacket and the communication location of the annular cooling portion where the pressure is lower than the cooling jacket, A part of the cooling water in the cooling jacket is forcibly taken into the annular cooling part provided in the valve holder, and the tip part of the fuel injection valve is effectively cooled.

At that time, the annular cooling part, the first valve holder cooling path, and the second valve holder cooling path are any one of the outer peripheral surface of the first valve holder and the inner peripheral surface of the second valve holder constituting the valve holder. Is formed by closing the groove or recess formed by plane machining on the other side, so that the groove is formed by plane machining on either the outer peripheral surface of the first valve holder or the inner peripheral surface of the second valve holder. The annular cooling section, the first valve holder cooling path, and the second valve holder cooling path can be formed simply by forming a recess or a recess, and the inner surface of the first valve holder or the second valve holder can be formed. A sufficiently large groove or recess can be secured with respect to the peripheral surface. Therefore, it is possible to easily create a cooling water channel that can obtain a high cooling effect.

  In the cooling device for a fuel injection valve according to an embodiment, the fuel injection valve, the cooling jacket, the annular cooling portion, the first valve holder cooling path, and the second valve holder cooling path are connected to the internal combustion engine. Provided for each cylinder, and in each cylinder, a throttle means is provided in a cylinder outlet branch pipe connecting the cooling jacket and the cooling water discharge passage, and the first valve holder cooling path and the cylinder outlet branch pipe Since the downstream side of the throttle means is connected by a connecting branch pipe, a positive pressure difference is positively provided between the cooling jacket and the first valve holder cooling path, and the cooling water is more forcibly cooled. It can be taken into the department.

  Further, since the throttle means is provided in the cylinder outlet branch pipe for each cylinder of the internal combustion engine, the temperature and flow rate of the cooling water in the cylinder outlet branch pipe can be measured for each cylinder. For example, it is possible to easily change the state of the cooling water in each cylinder independently of each other by adjusting the degree of throttling of the throttling means for each cylinder.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a diagram showing a cooling water path in a gas engine to which the fuel injection valve cooling device of the present embodiment is applied.

  A gas engine 51 shown in FIG. 1 is used as a drive source of a power generation system, and an output shaft of the gas engine 51 is connected to a generator 52. The gas engine 51 is, for example, 6 cylinders # 1 to # 6, and each of the cylinders # 1 to # 6 is used at the time of ignition of the gas fuel in addition to a gas fuel such as natural gas as a main fuel. Received liquid fuel supply. This liquid fuel is injected into each cylinder # 1 to # 6 from a fuel injection valve (see FIG. 2), and the injected liquid fuel ignites itself stably by igniting the gas fuel as the main fuel. .

  In FIG. 1, reference numeral 53 denotes a cooling water circulation path for circulating cooling water through the cylinder head of the gas engine 51. This cooling water circulation path 53 includes an engine cooling path 54 that exists in the gas engine 51 and passes through the cylinder heads of the cylinders # 1 to # 6, and a cooler 56 and a pump 57 that exist outside the gas engine 51. It is comprised with the external cooling path 55 interposed.

  The engine cooling passage 54 branches from the cooling water passage 58 as the cooling water supply passage passing through the inside of the engine frame and the cylinder heads of the cylinders # 1 to # 6. A branch path 59 that leads, a cylinder outlet branch pipe 60 that is attached to the outside of the cylinder head for each of the cylinders # 1 to # 6 and discharges cooling water from the cylinders # 1 to # 6, and each cylinder outlet branch pipe And a cooling water outlet main pipe 61 as a cooling water discharge passage that is connected in common to 60 and collects cooling water from each cylinder outlet branch pipe 60.

  The external cooling passage 55 connects the cooling water engine inlet 51a of the cooling water passage 58 and the cooling water engine outlet 51b of the cooling water outlet main pipe 61, and cools the cooling water sequentially from the cooling water engine outlet 51b side. For this purpose, a cooler 56 and a pump 57 for discharging cooling water toward the cooling water engine inlet 51a are provided. Therefore, the cooling water in the cooling water circulation path 53 is forcibly circulated by the pump 57 so as to flow from the cooling water path 58 to the cooling water outlet main pipe 61 through the branch path 59 and the cylinder outlet branch pipe 60. is there.

  Furthermore, a temperature regulating valve 62 comprising a three-way valve is interposed between the cooler 56 and the cooling water engine outlet 51b in the external cooling path 55, and the temperature regulating valve 62 is connected via the bypass path 63. It is connected to an external cooling path 55 between the cooler 56 and the pump 57. Thus, the distribution of the amount of cooling water flowing to the inlet side of the cooler 56 and the amount of cooling water flowing to the suction side of the pump 57 can be adjusted by the temperature adjustment valve 62. By doing so, the temperature of the cooling water discharged from the pump 57 can be adjusted.

  FIG. 2 is a sectional view of the cylinder head 64 in the gas engine 51. However, FIG. 2A is a cross-sectional view in a direction perpendicular to the extending direction of the cooling water passage 58 and the cooling water outlet main pipe 61, and FIG. 2B is a sectional view of the cooling water passage 58 and the cooling water outlet main pipe 61. It is sectional drawing to an extension direction. Here, since the fuel injection valve, the valve holder for holding the fuel injection valve, and the peripheral portion thereof for the cylinders # 1 to # 6 have the same configuration, one cylinder (for example, cylinder # 1) will be described below. This will be explained as a representative.

  In FIG. 2, the branch path 59 is disposed on both sides of the fuel injection valve 65 so as to sandwich the fuel injection valve 65. Then, the cooling water supplied from the branch path 59 passes through the periphery of the tip of the fuel injection valve 65 and enters the upper cylinder head cooling chamber 66 to cool the cylinder head 64, and then is attached to the outside of the cylinder head 64. The discharged cylinder outlet branch pipe 60 (see FIG. 1) is discharged.

  The fuel injection valve 65 is attached to the cylinder head 64 via a first valve holder 67 and a second valve holder 68, and the first valve holder 67 and the second valve holder 68 are connected to the tip of the fuel injection valve 65. Surrounding.

  FIG. 3 shows an enlarged view of the tip portion of the fuel injection valve 65 and the first valve holder 67 and the second valve holder 68. 3A is an enlarged cross-sectional view in the same direction as FIG. 2A, and FIG. 3B is an enlarged cross-sectional view in the same direction as FIG. 2B. Hereinafter, the fuel injection valve 65, the first valve holder 67, the second valve holder 68, and their peripheral parts will be described with reference to FIG.

  The second valve holder 68 is fitted with a tip portion of a first valve holder 67, and the second valve holder 68 surrounds the tip portion of the first valve holder 67. A mounting hole 69 in which the fuel injection valve 65 is mounted via the second valve holder 68 and the first valve holder 67 is formed in the cylinder head 64, and the inner peripheral surface of the mounting hole 69 and the second valve holder 68. A cooling jacket 70 communicating with the cylinder head cooling chamber 66 and the branch path 59 is formed between the outer peripheral surface. The cooling jacket 70 extends in the axial direction of the second valve holder 68, that is, in the axial direction of the fuel injection valve 65, and crosses the branch path 59. Thus, the cooling jacket 70 cools the fuel injection valve 65 via the second and first valve holders 68 and 67.

  Between the inner peripheral surface of the second valve holder 68 and the outer peripheral surface of the first valve holder 67 at the front end portion of the fuel injection valve 65, the vicinity of the front end portion of the nozzle (not shown) of the fuel injection valve 65 is provided. An annular cooling part 71 is formed so as to surround it. An annular groove 72 is formed on the outer peripheral surface of the first valve holder 67 surrounded by the second valve holder 68, and the second valve holder 68 communicates with the cooling jacket 70 in the second valve holder 68. A first opening 73 is formed. In the cross section shown in FIG. 3 (b), the annular cooling portion 71 is communicated with the annular groove 72 of the first valve holder 67 by the first valve holder cooling path 74, while the second valve holder cooling path 75 The two-valve holder 68 communicates with the first opening 73.

  Here, the annular cooling part 71, the annular groove 72, the first valve holder cooling path 74 and the second valve holder cooling path 75 have grooves and recesses formed on the surface of the first valve holder 67, and the second valve holder For example, it is formed by closing with 68 by welding. Accordingly, when forming the annular cooling part 71, the annular groove 72, the first valve holder cooling path 74 and the second valve holder cooling path 75, the surface of the first valve holder 67 is flattened to form grooves and recesses. It is only necessary to form a groove or recess having a sufficient area with respect to the surface of the first valve holder 67. That is, as compared with the case where the cooling water hole is formed by directly drilling or the like at the tip of the valve holder as in the case of the “cooling device for pilot fuel injection valve for gas engine” disclosed in Patent Document 2 above. Thus, a high cooling effect can be easily obtained.

  On the other hand, the second valve holder 68 is formed with a second opening 76 that allows the annular groove 72 to communicate with the outside of the second valve holder 68. The cylinder head 64 is formed with an internal connection path 77 extending outward from a position facing the second opening 76, and the internal connection path 77 is attached to the outside of the cylinder head 64. The cylinder outlet branch pipe 60 (see FIG. 1) is connected via a connection branch pipe 78. At that time, the connecting branch pipe 78 is connected to a low pressure portion provided in the cooling water circulation path 53. Specifically, as shown in FIG. 1 and FIG. 2 (a), an orifice 79 is interposed at a position located on the upper surface of the cylinder head 64 in the cylinder outlet branch pipe 60 of each of the cylinders # 1 to # 6. The internal pressure of the cooling water outlet main pipe 61 on the downstream side of the orifice 79 is kept lower than the internal pressure of the cooling water passage 58 by reducing the flow rate of the cooling water flowing in the cylinder outlet branch pipe 60. The connection branch pipe 78 is connected to the downstream side (low pressure side) of the orifice 79 in the cylinder outlet branch pipe 60.

  That is, the annular groove 72, the second opening 76, the internal connection path 77, and the connection branch pipe 78 are connected to the first opening 73 of the second valve holder 68 and the first valve holder cooling path 74 in the first valve holder 67. Thus, a connection path that connects the annular cooling part 71 and the second valve holder cooling path 75 to the low pressure part of the cylinder outlet branch pipe 60 is formed.

  In addition, the structure of this connection path is the same structure regarding each cylinder # 1- # 6.

  In the above configuration, the cooling water passage 58 is more specifically formed by a drill hole provided in the engine frame (not shown) in the gas engine 51, and the cooling water supplied from the pump 57. First flows into the cooling water passage 58 of the engine frame, and is branched into the cylinder heads, engine jackets and the like for the respective cylinders # 1 to # 6 in the engine frame. Then, for example, the cooling water branched to the cylinder head 64 of the cylinder # 1 passes through a hole 80 formed downward on the lower surface of the cylinder head 64 in FIGS. 2 (a) and 2 (b). It is supplied to the branch path 59 in the cylinder head 64 of the cylinder # 1.

  On the other hand, as shown in FIG. 2 (a), the cylinder outlet branch pipe 60, the connecting branch pipe 78 and the cooling water outlet main pipe 61 for guiding the cooling water discharged from the cylinder heads of the respective cylinders # 1 to # 6 The cylinder heads of the cylinders # 1 to # 6 communicate with an external cooling path 55 outside the gas engine 51 without passing through the engine frame.

  Moreover, the other structure of the said fuel injection valve 65 is the system similar to the conventional diesel engine engine automatic fuel valve and a common rail system electronically controlled fuel injection valve, for example, The detailed description is abbreviate | omitted.

  According to the cooling device for the fuel injection valve 65 having the above configuration, the annular cooling portion 71 formed in the tip portion of the first valve holder 67 is connected to the engine cooling passage 54 of the cooling water circulation passage 53, specifically, the cooling jacket 70. Is connected to the cooling jacket 70 via the annular groove 72, the second opening 76, the internal connection passage 77 and the connection branch pipe 78, and the low pressure downstream of the orifice 79 of the cylinder outlet branch pipe 60. Connected to the department. Therefore, a pressure difference is generated between both upper ends of the first valve holder cooling path 74 and the second valve holder cooling path 75 that sandwich the fuel injection valve 65. Therefore, as shown in FIG. 3, a part of the cooling water flowing in the branch passage 59 flows into the second valve holder cooling passage 75 from the upper end thereof, passes through the annular cooling portion 71, and the upper end of the first valve holder cooling passage 74. It will be forced to flow out from.

  4 is a sectional view taken along the line DD ′ in FIG. 3 (FIG. 4A), a sectional view taken along the line CC ′ (FIG. 4B), and a sectional view taken along the line BB ′ (FIG. 4). (c)), AA 'arrow sectional drawing (FIG.4 (d)) is shown. Hereinafter, the cooling water circulation system will be described in detail with reference to FIGS. 3 and 4.

  First, as shown in FIGS. 3 and 4C, the cooling water supplied from the branch path 59 flows into the lower part of the cooling jacket 70 formed around the second valve holder 68. Then, as shown in FIGS. 3 and 4B, the fuel injection valve 65 is cooled via the second valve holder 68 and the first valve holder 67 while rising in the cooling jacket 70. Thus, the cooling water reaching the upper portion of the cooling jacket 70 flows out into the cylinder head cooling chamber 66 as shown in FIGS. 3 and 4 (a), and the orifice 79 and the cylinder outlet as shown in FIG. 2 (a). The water is discharged to the cooling water outlet main pipe 61 through the branch pipe 60.

  On the other hand, a part of the cooling water supplied from the branch path 59 is caused by a pressure difference generated between the upper end of the first valve holder cooling path 74 and the upper end of the second valve holder cooling path 75 as shown in FIGS. As shown in c), the air is taken into the upper part of the second valve holder cooling path 75 through the first opening 73 of the second valve holder 68. Then, the fuel injection valve 65 is cooled via the first valve holder 67 while descending in the second valve holder cooling path 75. Thus, the cooling water that has reached the annular cooling section 71 effectively cools the tip of the nozzle of the fuel injection valve 65, as shown in FIGS. 3 and 4 (d). The cooling water flowing in the annular cooling unit 71 is taken into the lower part of the first valve holder cooling path 74 due to the pressure difference between the upper part and the lower part of the first valve holder cooling path 74. Then, as shown in FIG. 3 and FIG. 4 (c), the fuel injection valve 65 is cooled via the first valve holder 67 while rising in the first valve holder cooling path 74. Thus, the cooling water that has reached the annular groove 72 of the first valve holder 67 is, as shown in FIGS. 2A and 4B, the second opening 76 and the internal connection path 77 of the second valve holder 68. Then, the gas is discharged to the low pressure portion downstream from the orifice 79 through the connection branch pipe 78.

  As described above, according to the present embodiment, a large amount of cooling water can flow through the annular cooling portion 71 in the tip portion of the first valve holder 67. Therefore, this cooling water can effectively prevent overheating of the front end portion of the first valve holder 67, that is, the front end portion of the fuel injection valve 65. As a result, even if the needle valve collides with the valve seat of the nozzle when the fuel injection valve 65 is closed, the impact does not cause plastic deformation at the tip of the nozzle. Further, the nozzle hole of the nozzle is not blocked by fuel coking, and the needle valve is not seized against the nozzle.

  Further, the pressure difference between the connection end of the first valve holder cooling path 74 with the annular groove 72 and the connection end of the second valve holder cooling path 75 with the cooling jacket 70 causes an orifice 79 in the cylinder outlet branch pipe 60. It can be obtained simply by interposing. Therefore, a dedicated pump for forcibly introducing the cooling water into the second valve holder cooling path 75 is not required, the tip portion of the fuel injection valve 65 can be effectively cooled with a simple configuration and low cost, and the fuel injection Longer life of the valve 65 can be achieved.

  The annular cooling part 71 of the first valve holder 67 surrounds the tip of the nozzle of the fuel injection valve 65, and the outlet to the first valve holder cooling path 74 and the second valve for the annular cooling part 71. Since the inlets from the holder cooling path 75 are spaced apart from each other in the diameter direction of the annular cooling part 71, the cooling water in the annular cooling part 71 flows uniformly in the circumferential direction of the nozzle, and the nozzle Can be uniformly cooled in the circumferential direction.

  In the present embodiment, in each of the six cylinders # 1 to # 6, the connection end of the second valve holder cooling path 75 to the cooling jacket 70 and the annular groove 72 in the first valve holder cooling path 74 are connected. An orifice 79 for generating a pressure difference between the cylinder ends is provided in the cylinder outlet branch pipe 60 for each of the cylinders # 1 to # 6. Therefore, in the present embodiment, the temperature and flow rate of the cooling water in the cylinder outlet branch pipe 60 can be measured for each of the cylinders # 1 to # 6. Then, based on the measured value, for example, the diameter of the orifice 79 is adjusted for each of the cylinders # 1 to # 6, flows into the second valve holder cooling path 75 from its upper end, and passes through the annular cooling unit 71. The flow rate of the cooling water flowing out from the upper end of the first valve holder cooling path 74 is adjusted independently for each of the cylinders # 1 to # 6. Each of # 1 to # 6 can be easily changed independently of each other.

  In the present embodiment, the annular cooling part 71, the first valve holder cooling path 74, and the second valve holder cooling path 75 are provided with grooves and recesses formed in the outer peripheral surface of the first valve holder 67 as the second. It is formed by closing with a valve holder 68 and welding. Therefore, the annular cooling part 71, the first valve holder cooling path 74, and the second valve holder cooling path 75 can be formed simply by forming the groove and the concave portion on the surface of the first valve holder 67 by plane machining. A groove or recess having a sufficient area with respect to the outer peripheral surface of the one-valve holder 67 can be secured. That is, according to the present embodiment, it is possible to easily create a cooling water channel that can obtain a high cooling effect.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, the cooling device may include a pressure reducing valve instead of the orifice 79, and the specific layout of the first valve holder cooling path 74 and the second valve holder cooling path 75 can be arbitrarily changed.

  Moreover, in the said embodiment, the case where this invention is applied to a gas engine is mentioned as an example, and is demonstrated. However, the present invention is not limited to a gas engine, and can be applied to any internal combustion engine such as a diesel engine.

It is a figure which shows the cooling water path | route in the gas engine to which the cooling device of the fuel injection valve of this invention was applied. It is sectional drawing of the cylinder head of the gas engine in FIG. It is an enlarged view of the front-end | tip part of a fuel injection valve in FIG. 2, and a 1st valve holder and a 2nd valve holder. It is a cross-sectional view in FIG. It is a figure which shows the cross section of the fuel injection valve attachment structure in the conventional gas engine. It is a figure which shows the cooling device of the conventional pilot fuel injection valve for gas engines.

51 ... Gas engine,
51a ... cooling water engine inlet,
51b ... Cooling water engine outlet,
52 ... Generator,
53. Cooling water circuit,
54 ... Engine cooling path,
55 ... External cooling path,
56 ... Cooler,
57 ... pump,
58. Cooling water passage,
59 ... Branch,
60 ... Cylinder outlet branch pipe,
61. Cooling water discharge passage,
62 ... temperature control valve,
63 ... Bypass road,
64 ... Cylinder head,
65 ... fuel injection valve,
66 ... Cylinder head cooling chamber,
67 ... first valve holder,
68 ... second valve holder,
69 ... Fuel injection valve mounting hole,
70 ... Cooling jacket,
71 ... An annular cooling section,
72: An annular groove,
73 ... 1st opening part,
74 ... 1st valve holder cooling path,
75 ... second valve holder cooling path,
76 ... the second opening,
77. Internal connection path,
78 ... Connecting branch pipe,
79: Orifice.

Claims (3)

A fuel injection valve attached to a cylinder head of the internal combustion engine via a valve holder and supplying fuel to the combustion chamber of the internal combustion engine;
A cooling water supply passage for supplying cooling water into the cylinder head; a cooling jacket for passing the cooling water around the valve holder; and cooling water after passing through the cooling jacket from the cylinder head to the cylinder head An engine cooling path that forcibly flows cooling water from the cooling water supply path to the cooling water discharge path.
An annular cooling portion provided at a tip portion in the valve holder so as to surround the tip portion of the fuel injection valve, and in which cooling water for cooling the tip portion of the fuel injection valve is circulated;
A first valve holder cooling path for communicating the annular cooling portion provided in the valve holder to a location where the pressure is lower than the cooling jacket in the engine cooling path;
A second valve holder cooling passage that communicates the annular cooling portion provided in the valve holder with the cooling jacket;
The valve holder includes a first valve holder to which the tip of the fuel injection valve is closely attached and a second valve holder to which the tip of the first valve holder is closely attached,
The annular cooling section, the first valve holder cooling path, and the second valve holder cooling path are grooves formed by plane machining on one of the outer peripheral surface of the first valve holder and the inner peripheral surface of the second valve holder. Alternatively, the cooling device for the fuel injection valve is formed by closing the concave portion with the other. The fuel injection valve cooling device according to claim 1,
The fuel injection valve, the cooling jacket, the annular cooling section, the first valve holder cooling path and the second valve holder cooling path are provided for each cylinder of the internal combustion engine,
For each cylinder above,
A cylinder outlet branch pipe that connects the cooling jacket and the cooling water discharge passage and is provided with a throttle means;
A cooling device for a fuel injection valve, comprising: a connecting branch pipe that connects the first valve holder cooling path and a downstream side of the throttle means in the cylinder outlet branch pipe. The cooling device for a fuel injection valve according to claim 2,
The fuel injection valve cooling apparatus according to claim 1, wherein the throttle means provided in the cylinder outlet branch pipe is an orifice.

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