JP4376275B2 - Cooled fuel injection valve structure for gas engine - Google Patents

Description

  The present invention relates to a fuel injection valve structure for 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. 6 shows a cross section of the fuel injection valve mounting structure in the gas engine disclosed in Patent Document 1. In FIG. 6, 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 a communication hole for communicating the main combustion chamber 4 and the sub-chamber 7, and 9 a glow plug for preheating at start-up. Further, the fuel injection valve 3 includes a nozzle tip 10, a plurality of nozzle holes 11 (see FIG. 7) drilled at the tip of the nozzle tip 10, and a needle valve 12 fitted in the nozzle tip 10 so as to be slidable back and forth. , A nozzle nut 13 and a nozzle body 14.

  During operation of the gas engine, pilot liquid fuel is injected from the injection hole 11 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 done. In that case, the vicinity of the tip of the nozzle tip 10 of the fuel injection valve 3 is heated to a high temperature by the combustion gas in the sub chamber 7 due to the ignition combustion. However, the nozzle tip 10 has a sheet portion 15 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 15a and the base side sheet surface 15b 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 15, 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.

  Further, the micropilot gas engine has poor ignitability when it is in a cold state such as at the time of startup. Therefore, as shown in FIG. 6, the upper sub-chamber base 6 penetrates in substantially the same direction as the fuel injection valve 3, and the glow plug 9 is installed with its tip end exposed in the sub-chamber 7. In the sub chamber 7, the gas fuel in the vicinity where the pilot liquid fuel is sprayed is warmed by the glow plug 9 to improve the ignitability of the air-fuel mixture.

  However, the conventional fuel injection valve mounting structure disclosed in Patent Document 1 has the following problems.

  That is, the fuel injection valve 3 used in the micropilot gas engine is structurally directly facing the sub chamber 7 (or the main combustion chamber 4), and directly receives the combustion heat generated by the combustion. Become. Further, the pilot liquid fuel injected from the fuel injection valve 3 into the sub chamber 7 is compressed to about 1000 bar in advance by a common rail system or the like. The compression of the pilot liquid fuel is accompanied by an increase in temperature. Further, since the pilot liquid fuel compressed to a high pressure passes through a pilot liquid fuel inflow hole (not shown) of the nozzle body 14 at a high speed, frictional heat is generated at that time. Further, the injection amount of the pilot liquid fuel is small, and therefore the cooling effect by the pilot liquid fuel itself is small. When subjected to the thermal influence as described above, there is a high possibility that problems such as irregular injection due to the occurrence of coking of the pilot liquid fuel and seizure of the needle valve 12 due to high temperature in the vicinity of the nozzle head will occur.

  Therefore, in order to solve the problems associated with the high temperature of the fuel injection valve 3 as described above, in the conventional fuel injection valve mounting structure disclosed in Patent Document 1, the fuel injection valve 3 is shown in FIG. As described above, the sheet portion 15 of the nozzle tip 10 and the upper sub-chamber base 6 is formed in a conical surface (cone surface) symmetrical to the axis of the fuel injection valve 3 and is formed in the vicinity of the tip of the nozzle tip 10. The nozzle-side sheet surface 15a and the base-side sheet surface 15b formed on the upper sub-chamber base 6 are brought into direct contact with each other in a fluid-tight manner and are brought into pressure contact with the upper sub-chamber base 6. Thus, 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 15, and is transmitted from the outer surface of the upper sub chamber base 6 to the cooling water in the cooling water chamber 2. The chip 10 is indirectly cooled through the upper sub chamber base 6.

  However, the cooling water chamber 2 is formed in the cylinder head 1, and indirect cooling through the upper sub-chamber base 6 by the cooling water flowing through the cooling water chamber 2 is somewhat more effective than nothing. Is obtained, but there is a problem that it has not reached a complete countermeasure for the above-mentioned problem.

  In the conventional fuel injection valve mounting structure disclosed in Patent Document 1, the glow plug 9 is installed separately from the fuel injection valve 3 through the upper sub-chamber base 6 in a substantially vertical direction. is doing. Therefore, it is inevitably necessary to offset the fuel injection valve 3, that is, the injection hole 11 with respect to the center of the sub chamber 7, as shown in FIG. As a result, the injection position of the pilot liquid fuel is offset, which affects the injection / combustion performance, and the engine performance as expected cannot be obtained.

Furthermore, it is necessary to form a hole for inserting the fuel injection valve 3 and a hole for inserting the glow plug 9 in the upper sub chamber base 6, and there is a problem that the strength of the upper sub chamber base 6 is lowered. Further, when the diameter of the upper sub-chamber base 6 is increased in order to maintain the strength of the upper sub-chamber base 6, the diameter of the upper sub-chamber base 6 insertion hole formed in the cylinder head 1 must be increased. There arises a problem that the strength of the cylinder head 1 is lowered.
Japanese Patent Laid-Open No. 2003-254195

  Therefore, an object of the present invention is to provide a cooling type fuel injection valve structure for a gas engine that can directly cool the nozzle head in the fuel injection valve of the gas engine with cooling water and does not need to offset the injection position of the pilot liquid fuel. It is to provide.

In order to solve the above problems, a cooling type fuel injection valve structure for a gas engine according to the present invention comprises:
A fuel injection valve body for supplying liquid fuel into the pre-combustion chamber of the micro-pilot type gas engine,
Together is attached to the tip of the fuel injection valve body, a nozzle tip nozzle is provided for injecting the liquid fuel supplied from the fuel injection valve body to the pre-combustion chamber,
A holder guide for internally fitting the fuel injection valve body and the nozzle tip;
A cylinder head to which the holder guide is attached,
The nozzle tip has a nozzle seat at the tip thereof and a valve seat on which a needle valve for opening and closing the nozzle is seated,
An annular cooling liquid passage formed to surround the valve seat immediately adjacent to the valve seat at the tip of the nozzle tip;
A cooling liquid supply passage formed in the holder guide, the fuel injection valve main body, and the nozzle tip for supplying a cooling liquid to the cooling liquid passage;
A cooling liquid recovery passage formed in the holder guide, the fuel injection valve main body, and the nozzle tip for recovering the cooling liquid from the cooling liquid passage;
Cooling liquid introduction that is formed in the cylinder head in a direction intersecting the central axis of the fuel injection valve body and the nozzle tip, and communicates with the cooling liquid supply passage to introduce the cooling liquid into the cooling liquid supply passage. Holes,
A cooling liquid that is formed in the cylinder head in a direction intersecting with the central axis of the fuel injection valve main body and the nozzle tip and communicates with the cooling liquid recovery passage to draw out the cooling liquid from the cooling liquid recovery passage In the cooling type fuel injection valve structure of the gas engine further comprising a lead-out hole ,
Along the central axis of the fuel injection valve main body and the nozzle tip attached to the tip of the fuel injection valve main body, the fuel injection valve main body and the nozzle tip are penetrated, and the nozzle hole in the nozzle tip is A glow plug insertion hole provided with an opening on the provided end surface;
A glow plug that is inserted into and attached to the glow plug insertion hole so that the tip protrudes from the opening provided on the end face of the nozzle tip and warms the gas in the vicinity of which fuel is injected from the nozzle port of the nozzle tip;
It is characterized by comprising a.

  According to the above configuration, the annular cooling liquid formed surrounding the valve seat immediately adjacent to the valve seat of the needle valve that opens and closes the nozzle nozzle at the tip of the nozzle tip attached to the tip of the fuel injection valve body. The cooling liquid can be supplied to and recovered from the passage through the cooling liquid supply passage, the cooling liquid introduction hole, the cooling liquid recovery passage, and the cooling liquid outlet hole. Therefore, the needle valve and its valve seat located in the immediate vicinity of the annular cooling liquid passage can be directly cooled.

  Therefore, the tip of the fuel injection valve body and the nozzle tip can be protected from thermal influences. As a result, it is possible to suppress problems such as irregular injection due to the occurrence of coking of fuel oil and seizure of the needle valve due to high temperature near the tip of the nozzle tip.

Further, the cooling liquid introduction hole and the cooling liquid lead-out hole are formed in the cylinder head in a direction crossing the central axes of the fuel injection valve body and the nozzle tip. Therefore, when carrying out periodic inspections on the fuel supply / discharge system, it is only necessary to pull the holder guide upward from the cylinder head, and supply / discharge the cooling liquid to / from the cooling liquid supply passage and the cooling liquid recovery passage. It can be done easily without being disturbed by the piping. Further, even when a leak occurs in the pipe connected to the cooling liquid introduction hole and the cooling liquid outlet hole, the pipe is located on the side surface of the cylinder head, so that the valve operating mechanism disposed on the cylinder head. Can be prevented from affecting the lubricity of the valve operating mechanism .

Further , a glow plug for warming a gas in the vicinity of the nozzle where the fuel is injected from the nozzle hole is inserted into a glow plug insertion hole penetrating the fuel injection valve body and the nozzle chip and attached. Therefore, unlike the prior art, it is not necessary to offset the fuel injection valve composed of the fuel injection valve body and the nozzle tip, that is, the nozzle nozzle, with respect to the center of the combustion chamber. As a result, the expected engine performance can be obtained without affecting the injection / combustion performance.

Further, it is not necessary to form the glow plug insertion hole in addition to the fuel injection valve insertion hole in the holder guide, and the strength of the holder guide does not decrease. Therefore, it is not necessary to increase the diameter of the holder guide, and the strength of the cylinder head does not decrease .

Furthermore , in the micropilot gas engine, the tip of the fuel injection valve body and the nozzle tip can be protected from the thermal influence of liquid fuel combustion in the pre-combustion chamber.

  As is clear from the above, the cooling type fuel injection valve structure for a gas engine according to the present invention forms an annular cooling liquid passage surrounding the valve seat in the vicinity of the valve seat for the needle valve in the nozzle tip. Since the cooling liquid is supplied to and recovered from the cooling liquid passage through the cooling liquid supply passage, the cooling liquid introduction hole, the cooling liquid recovery passage, and the cooling liquid outlet hole, the needle positioned in the immediate vicinity of the annular cooling liquid passage The valve and its seat can be cooled directly.

  Therefore, the tip of the fuel injection valve main body and the nozzle tip can be protected from thermal influences, such as irregular injection due to the occurrence of coking of fuel oil, and seizure of the needle valve due to high temperature near the tip of the nozzle tip. Can be suppressed.

  Further, the cooling liquid introduction hole and the cooling liquid lead-out hole are formed in the cylinder head in a direction crossing the central axes of the fuel injection valve body and the nozzle tip. Therefore, when carrying out periodic inspections on the fuel supply / discharge system, it is only necessary to pull the holder guide upward from the cylinder head, and supply / discharge the cooling liquid to / from the cooling liquid supply passage and the cooling liquid recovery passage. It can be done easily without being disturbed by the piping. Further, even when a leak occurs in the piping connected to the cooling liquid introduction hole and the cooling liquid outlet hole, the valve mechanism arranged on the cylinder head does not get wet, and the valve mechanism is lubricated. It is possible to prevent the influence on the sex and the like.

Furthermore, since the glow plug that warms the gas in the vicinity where the fuel is injected from the nozzle hole of the nozzle tip is inserted into and attached to the glow plug insertion hole that penetrates the fuel injection valve body and the nozzle tip, As in the prior art, it is not necessary to offset the fuel injection valve comprising the fuel injection valve body and the nozzle tip, that is, the nozzle nozzle, with respect to the center of the combustion chamber. As a result, the expected engine performance can be obtained without affecting the injection / combustion performance.

Further, it is not necessary to form the glow plug insertion hole in addition to the fuel injection valve insertion hole in the holder guide, and the strength of the holder guide does not decrease. Therefore, it is not necessary to increase the diameter of the holder guide, and the strength of the cylinder head does not decrease.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 shows a cross section of a cylinder head portion provided with a cooling type fuel injection valve structure for a gas engine of the present embodiment.

  In FIG. 1, a gas engine 21 includes a cylinder liner 22, a piston 23 that reciprocates up and down in the cylinder liner 22, and a fuel injection valve 24. And a cylinder head 27 provided with a holder guide 26 having a sub-chamber 25 as a pre-combustion chamber.

  The holder guide 26 is disposed at a substantially central portion of the cylinder head 27 so as to face the central portion of the cylinder liner 22. The holder guide 26 is provided with a sub chamber nozzle 28 having a smaller diameter than the sub chamber 25 and communicating with the sub chamber 25 at the tip of the sub chamber 25. The tip of the sub chamber nozzle 28 is exposed to the main combustion chamber 29 defined by the cylinder liner 22, the piston 23, and the cylinder head 27, and the sub chamber 25 communicates with the exposed portion of the sub chamber 25 into the main combustion chamber 29. A plurality of nozzle holes 28a are provided radially.

  The fuel injection valve 24 includes an injection body 30 as the fuel injection valve main body and a nozzle tip 31 that is tightly fixed to the end surface of the tip of the injection body 30. A needle valve 32 for injecting and stopping liquid fuel into the sub chamber 25 is disposed along the central axis in the injection body 30 and the nozzle tip 31, and in the vicinity of the needle valve 32, A glow plug 33 is installed substantially parallel to the needle valve 32. Further, with respect to the injection body 30, a cooling water introduction hole 34 and a cooling water outlet hole 35 formed in the radial direction in the cylinder head 27, and an engine inlet portion of the cooling water system connected to both the holes 34 and 35. Cooling water is supplied and discharged through pipes 36 and 37 branched from the pump outlet.

  FIG. 2 shows a longitudinal section including the central axis of the fuel injection valve 24. 2A shows a cross section at the same position as in FIG. FIG. 2 (b) shows a cross section at a position rotated by 90 ° with respect to the cross sectional position in FIG. 2 (a). 3 shows a view of the fuel injection valve 24 as viewed from above with the cylinder head 27 attached, that is, from the left in the state of FIG. 2A is a cross-sectional view taken along the line AA ′ in FIG. FIG. 2B is a cross-sectional view taken along the line BB ′ in FIG.

  As shown in FIGS. 2 and 3, in the fuel injection valve 24, the injection body 30 and the nozzle tip 31 are connected to the end face 30 a on the distal end side of the injection body 30 and the end face 31 a of the nozzle tip 31 by a cap nut 41. It is configured to be in close contact and fixed. Needle valve insertion holes 42 and 43 for needle valve insertion are formed in the injection body 30 and the nozzle tip 31 along the central axis. The needle valve insertion hole 42 formed in the injection body 30 has an injection The liquid fuel is supplied through a liquid fuel supply hole 44 provided in the body 30 in the radial direction. The needle valve 32 is inserted into the needle valve insertion holes 42 and 43 so as to be able to advance and retract in the direction of the central axis. In FIG. 2, only the tip of the needle valve 32 is depicted.

  Further, as shown in FIG. 2 (a), a glow plug insertion hole 45 for inserting a glow plug is formed in the injection body 30 and the nozzle tip 31 substantially in parallel with the needle valve insertion holes 42 and 43. The glow plug 33 is inserted and fixed in the glow plug insertion hole 45 as shown in FIG.

  Further, as shown in FIG. 2B, a first cooling water supply passage 46 is formed on the distal end side of the injection body 30 in parallel with the central axis. As shown in FIG. 1, one end of the first cooling water supply passage 46 communicates with a cooling water inflow hole 47 that is formed in the injection body 30 in the radial direction and communicates with the cooling water introduction hole 34 of the cylinder head 27. ing. On the other hand, the other end of the first cooling water supply passage 46 is open to the end face 30 a of the injection body 30. Similarly, a first coolant recovery passage 48 is formed on the distal end side of the injection body 30 in parallel with the central axis. As shown in FIG. 1, one end of the first cooling water recovery passage 48 communicates with a cooling water outflow hole 49 that is formed in the injection body 30 in the radial direction and communicates with the cooling water outlet hole 35 of the cylinder head 27. ing. On the other hand, the other end of the first cooling water recovery passage 48 opens to the end face 30 a of the injection body 30.

  Further, the nozzle tip 31 is formed with a second cooling water supply passage 50 and a second cooling water recovery passage 51 that are inclined so as to approach the central axis toward the tip side. The end of the second cooling water supply passage 50 on the injection body 30 side is open to the end surface 31 a and can communicate with the other end of the first cooling water supply passage 46. Similarly, the end of the second cooling water recovery passage 51 on the injection body 30 side is open to the end surface 31 a and can communicate with the other end of the first cooling water recovery passage 48.

  FIG. 4 is an enlarged view of a portion C in FIG. However, FIG. 4 (a) shows a cross section in the same direction as FIG. 2 (b). FIG. 4B is a cross-sectional view corresponding to the cross section taken along the line DD ′ in FIG. As shown in FIG. 4 (a), an injection hole 52 communicating with the tip of the needle valve insertion hole 43 is formed along the central axis at the center of the end surface 31 b on the tip side of the nozzle tip 31. As the valve advances and retreats in the direction of the central axis, the nozzle 52 is opened and closed, and liquid fuel is injected and stopped.

  4B, the tip of the nozzle tip 31 is connected to the other ends of the second cooling water supply passage 50 and the second cooling water recovery passage 51, and the needle valve 32. An annular cooling water passage 54 is provided so as to surround the immediate vicinity of the valve seat 53 on which is seated. The cooling water passage 54 is covered with a cooling water passage lid 55 that is laser welded or brazed to prevent leakage of the cooling water.

  In the above configuration, when the cooling water is supplied to the cooling water introduction hole 34 via the piping 36 of the cooling water system, the cooling water inflow hole 47 formed in the radial direction in the injection body 30 and the cooling water inflow hole Cooling water is supplied to the annular cooling water passage 54 via the first cooling water supply passage 46 and the second cooling water supply passage 50 communicated with 47. In this way, the cooling water supplied to the cooling water passage 54 cools the valve seat 53 of the needle valve 32 positioned closest to the annular cooling water passage 54 while rotating in the annular cooling water passage 54. At that time, the annular cooling water passage 54 is formed on the tip side of the nozzle tip 31 so as to surround the vicinity of the valve seat 53 of the needle valve 32. Therefore, instead of indirect cooling via the holder guide 26 (upper sub-chamber base) as in the conventional fuel injection valve mounting structure disclosed in Patent Document 1, cooling water is forced to the tip of the nozzle tip 31. The needle valve 32 and its valve seat 53 can be directly cooled.

  Therefore, when directly receiving the combustion heat generated by the combustion in the sub chamber 25 facing the nozzle tip 31, the liquid fuel compressed to a high pressure by the common rail method or the like passes through the liquid fuel supply hole 44 at a high speed. Thus, the fuel injection valve 24 can be protected from thermal influences such as the generation of frictional heat and the small amount of the liquid fuel injected, so that the cooling effect of the liquid fuel itself is small. As a result, it is possible to suppress the occurrence of problems such as irregular injection due to the occurrence of fuel oil coking and seizure of the needle valve 32 due to high temperatures near the tip of the nozzle tip.

  Thus, the cooling water that has been cooled while circulating in the annular cooling water passage 54 flows into the second cooling water recovery passage 51 when reaching the other end of the second cooling water recovery passage 51, and A piping 37 of the cooling water system is provided via a cooling water outlet hole 49 formed in the cooling water recovery passage 48 and the injection body 30 in the radial direction and a cooling water outlet hole 35 communicated with the cooling water outlet hole 49. It will be recovered.

  In this case, the cooling water is supplied to the first cooling water supply passage 46 in the injection body 30 by cooling water introduction holes 34 formed in the radial direction in the cylinder head 27 and cooling formed in the injection body 30 in the radial direction. This is performed through the water inflow hole 47. In addition, cooling water recovery from the first cooling water recovery passage 48 in the injection body 30 is performed by cooling water discharge holes 35 formed in the radial direction in the cylinder head 27 and cooling water outflow formed in the injection body 30 in the radial direction. Through hole 49. Therefore, when carrying out periodic inspections on the fuel supply / discharge system, it is only necessary to pull the holder guide 26 upward from the cylinder head 27, and the coolant for the first coolant supply passage 46 and the first coolant recovery passage 48. This can be done easily without being obstructed by the piping that supplies and drains the water. Further, even when water leakage occurs in the pipes including the pipes 36 and 37 connected to the cooling water introduction hole 34 and the cooling water outlet hole 35, the pipe is located on the side surface of the cylinder head 27. The arranged valve mechanism does not get wet and does not affect the lubricity and the like of the valve mechanism.

  FIG. 5 shows a circulation system of liquid fuel and cooling water for the cooling type fuel injection valve having the above-described configuration. The liquid fuel as the pilot oil from the fuel tank 61 is compressed to about 1000 bar by the pump 62, and then the plurality of fuel injection valves 24 of the gas engine 21 by the pilot fuel supply line 63 and the plurality of branch lines 64 of the common rail system. To be supplied. In this way, the liquid fuel supplied to the fuel injection valve 24 is controlled to be injected / stopped into the sub chamber 25 by the needle valve 32, and is injected into the sub chamber 25 in the second half of the compression stroke by the piston 23 to be compressed and ignited. The air-fuel mixture in the main combustion chamber 29 is combusted using this as an ignition source.

  Excess liquid fuel that has not been injected by the fuel injection valves 24 is returned to the fuel tank 61 by a return branch line 65 and a pilot fuel return line 66.

  On the other hand, the cooling water cooled to a predetermined temperature by the fresh water cooler 67 is supplied to the gas engine 21 by the temperature control valve 68 and the cooling water pump 69 to cool each part of the gas engine 21. At that time, the cooling water branched to the nozzle cooling line 70 at the inlet of the gas engine 21 is provided with annular cooling water passages 54 provided at the front ends of the plurality of nozzle chips 31 in the gas engine 21 by the plurality of branch lines 71. To be supplied. Thus, the liquid fuel supplied to the cooling water passage 54 directly cools the needle valve 32 and its valve seat 53 in the nozzle head.

  The cooling water after cooling in the annular cooling water passage 54 is returned to the cooling water pump 69 by the return branch line 72 and the nozzle cooling return line 73 to the suction port.

  As described above, by using the cooling water circulation system that returns the cooling water branched and supplied from the cooling water pump 69 to the suction port of the cooling water pump 69, the discharge port and the suction port of the cooling water pump 69 are sucked. The cooling water can be forcibly supplied to the tip of the nozzle tip 31 by the pressure difference with the mouth. Therefore, the needle valve 32 and its valve seat 53 can be directly cooled by the cooling water forcibly supplied to the cooling water passage 54.

  In the present embodiment, cooling water is used as a heat medium supplied to the cooling water passage 54 at the tip of the nozzle tip 31. However, a refrigerant may be used. Further, pilot oil may be used as the refrigerant. You may utilize the liquid fuel to be used.

  By the way, as described above, in the conventional fuel injection valve mounting structure disclosed in Patent Document 1, the glow plug for eliminating the poor ignitability in the cold state such as the start-up is provided in the present embodiment. The upper sub-chamber base corresponding to the holder guide 26 in the form is installed separately from the fuel injection valve. Therefore, it is necessary to offset the fuel injection valve with respect to the center of the sub chamber. The offset of the injection position of the liquid fuel affects the injection / combustion performance, and the engine performance as expected cannot be obtained. Furthermore, it is necessary to form holes for fuel injection valve insertion and glow plug insertion in the holder guide (upper sub-chamber base), and the strength of the holder guide is reduced. In addition, when the diameter of the holder guide is increased in order to maintain the strength of the holder guide (upper sub chamber cap), the diameter of the hole for inserting the holder guide is also increased, and the strength of the cylinder head is reduced. End up.

  However, in the present embodiment, as shown in FIG. 2, a glow plug insertion hole 45 is formed in the injection body 30 and the nozzle tip 31 constituting the fuel injection valve 24, and a glow plug insertion hole 45 is formed in the glow plug insertion hole 45. The plug 33 is inserted and fixed. Therefore, it is not necessary to offset the injection port 52 in the nozzle tip 31, that is, the injection position of the liquid fuel from the center of the sub chamber 25. As a result, the injection position of the liquid fuel does not affect the injection / combustion performance, and the expected engine performance can be obtained.

  Further, it is not necessary to form a hole for inserting the glow plug 33 in addition to the hole for inserting the fuel injection valve 24 into the holder guide 26, and the strength of the holder guide 26 does not decrease. Therefore, it is not necessary to increase the diameter of the holder guide 26, and the strength of the cylinder head 27 does not decrease.

It is a figure which shows the cross section of the cylinder head part provided with the cooling type fuel injection valve structure of the gas engine of this invention. It is a figure which shows the longitudinal cross-section containing the center axis | shaft of the fuel injection valve in FIG. It is the figure which looked at the fuel injection valve shown in FIG. 2 from the left side in the figure. FIG. 3 is an enlarged view of a portion C in FIG. It is a figure which shows the circulation system of the liquid fuel and cooling water with respect to the said cooling type fuel injection valve. It is a figure which shows the cross section of the fuel injection valve attachment structure of the conventional gas engine. It is the Z section enlarged view in FIG.

21 ... Gas engine,
22 ... Cylinder liner,
23 ... Piston,
24 ... Fuel injection valve,
25 ... Subroom,
26 ... Holder guide,
27 ... Cylinder head,
28 ... Sub chamber nozzle,
29 ... main combustion chamber,
30 ... Injection body,
31 ... Nozzle tip,
32 ... Needle valve,
33 ... Glow plug,
34 ... cooling water introduction hole,
35 ... cooling water outlet hole,
41 ... Cap nut,
42, 43 ... Needle valve insertion hole,
44 ... Liquid fuel supply hole,
45 ... Glow plug insertion hole,
46: first cooling water supply passage,
47. Cooling water inflow hole,
48 ... first cooling water recovery passageway,
49. Cooling water outflow hole,
50. Second cooling water supply passage,
51 ... second cooling water recovery passageway,
52 ...
53 ... valve seat,
54. Cooling water passage,
55. Cooling water passage lid,
61 ... Fuel tank,
62 ... pump,
63 ... pilot fuel supply line,
64, 71 ... branch line,
65,72 ... return branch line,
66 ... pilot fuel return line,
67 ... Shimizu cooler,
69 ... Cooling water pump,
70: Nozzle cooling line,
73 ... Nozzle cooling return line

Claims (1)

A fuel injection valve body for supplying liquid fuel into the pre-combustion chamber of the micro-pilot type gas engine,
Together is attached to the tip of the fuel injection valve body, a nozzle tip nozzle is provided for injecting the liquid fuel supplied from the fuel injection valve body to the pre-combustion chamber,
A holder guide for internally fitting the fuel injection valve body and the nozzle tip;
A cylinder head to which the holder guide is attached,
The nozzle tip has a nozzle seat at the tip thereof and a valve seat on which a needle valve for opening and closing the nozzle is seated,
An annular cooling liquid passage formed to surround the valve seat immediately adjacent to the valve seat at the tip of the nozzle tip;
A cooling liquid supply passage formed in the holder guide, the fuel injection valve main body, and the nozzle tip for supplying a cooling liquid to the cooling liquid passage;
A cooling liquid recovery passage formed in the holder guide, the fuel injection valve main body, and the nozzle tip for recovering the cooling liquid from the cooling liquid passage;
Cooling liquid introduction that is formed in the cylinder head in a direction intersecting the central axis of the fuel injection valve body and the nozzle tip, and communicates with the cooling liquid supply passage to introduce the cooling liquid into the cooling liquid supply passage. Holes,
A cooling liquid that is formed in the cylinder head in a direction intersecting with the central axis of the fuel injection valve main body and the nozzle tip and communicates with the cooling liquid recovery passage to draw out the cooling liquid from the cooling liquid recovery passage In the cooling type fuel injection valve structure of the gas engine further comprising a lead-out hole ,
Along the central axis of the fuel injection valve main body and the nozzle tip attached to the tip of the fuel injection valve main body, the fuel injection valve main body and the nozzle tip are penetrated, and the nozzle hole in the nozzle tip is A glow plug insertion hole provided with an opening on the provided end surface;
A glow plug that is inserted into and attached to the glow plug insertion hole so that the tip protrudes from the opening provided on the end face of the nozzle tip and warms the gas in the vicinity of which fuel is injected from the nozzle port of the nozzle tip;
Cooling type fuel injection valve structure for a gas engine, comprising the.

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