JP2005180252A - Injection pump, and liquified gas fuel supply device for diesel engine provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of lubricating performance of lubricating oil caused by mixing liquified gas fuel in the lubricating oil inside a cam chamber. <P>SOLUTION: Three annular grooves 20 are formed in an inner circumferential face of a plunger barrel 25, into which a plunger 26 is inserted, in a circumferential direction of the inner circumferential face of the plunger barrel 25. The annular grooves 20 form spaces 20a in a slide-contact face between the plunger 26 and plunger barrel 25. The liquified gas fuel leaks from an oil reservoir chamber 11 to the slide-contact face between the plunger 26 and the plunger barrel 25, and then the fuel leaks to the cam chamber 15 with a state where the fuel is depressurized stepwise in the three spaces and is gasified. The liquified fuel gas leaking to the cam chamber 15 is separated from the lubricating oil by an oil separator 6 disposed to the cam chamber 15, sucked by a compressor 61, and then is sent to a fuel tank 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an injection pump for a liquefied gas fuel supply device of a diesel engine using a liquefied gas such as LP gas (hereinafter referred to as “high cetane number LP gas”) or DME (dimethyl ether) to which a cetane number improver is added. And a liquefied gas fuel supply apparatus for a diesel engine equipped with the injection pump.

  As a measure against air pollution by diesel engines, attention has been focused on using high-cetane LP gas with clean exhaust gas or DME (dimethyl ether) as fuel instead of diesel oil. These fuels are liquefied gas fuels unlike light oil which is a conventional fuel. That is, the boiling point temperature is lower than that of light oil, and light oil is liquid at normal temperature under atmospheric pressure, whereas high cetane number LP gas and DME have a property of becoming gas at normal temperature. For this reason, when liquefied gas fuel is used in a conventional diesel engine, the liquefied gas fuel is vaporized if the supply pressure to the injection pump is low. Therefore, in order to supply the liquid liquefied gas fuel to the injection pump, it is necessary to increase the supply pressure to the injection pump rather than the light oil fuel (Patent Document 1, etc.).

  Therefore, when liquefied gas fuel is used in a conventional diesel engine, the gap between the plunger barrel and the plunger of the injection pump that sends the liquefied gas fuel to the fuel injection nozzle of the engine due to the high supply pressure to the injection pump, There arises a problem that the amount of fuel leaking into the cam chamber of the injection pump is significantly increased as compared with the case where light oil fuel is used. Moreover, since the liquefied gas fuel has a low viscosity as compared with light oil, the liquefied gas fuel easily leaks from the gap, and the amount thereof increases. And when the liquid liquefied gas fuel leaked from the gap between the plunger barrel and the plunger flows into the cam chamber of the injection pump and enters the lubricating oil in the cam chamber, the viscosity of the lubricating oil decreases, There is a risk of hindering the operation of the injection pump. The liquid liquefied gas fuel mixed in this lubricating oil is difficult to separate and remove, and it takes a long time to escape from the lubricating oil by vaporization. In the injection pump of the apparatus, it is an object to reduce as much as possible the liquid liquefied gas fuel that leaks into the cam chamber from the gap between the plunger barrel and the plunger.

  However, even if the plunger barrel and the plunger are formed with high accuracy and the gap between the plunger barrel and the plunger is made as small as possible, there is a limit to reducing the amount of liquefied gas fuel that leaks. Therefore, as an example of means for solving such a problem, the lubricating oil is separated from the vaporized liquefied gas fuel filled in the gas portion in the cam chamber by an oil separator, and the separated gaseous liquefied gas fuel is sucked. And return it to the fuel tank. As a result, the vaporization of the liquid liquefied gas fuel leaking into the cam chamber is promoted, and the amount of the liquid liquefied gas fuel mixed in the lubricating oil in the liquid state can be reduced, and the liquid liquefied liquid mixed in the lubricating oil can be reduced. Since the vaporization of the gas fuel is promoted and the time for separating the liquid liquefied gas fuel from the lubricating oil can be shortened, the decrease in the lubricating performance of the lubricating oil due to the liquefied gas fuel being mixed into the lubricating oil is reduced. can do.

Japanese Patent Laid-Open No. 2003-206824

  However, as long as the liquid liquefied gas fuel leaks into the cam chamber, it is inevitable that the liquid liquefied gas fuel is mixed into the lubricating oil, and it is impossible to prevent the liquefied gas fuel from being mixed. It was. Therefore, it has not been possible to prevent the liquefied gas fuel from being mixed into the lubricating oil and deteriorating the lubricating performance of the lubricating oil.

  The present invention has been made in view of such a situation, and its problem is to prevent a decrease in the lubricating performance of the lubricating oil due to the liquid liquefied gas fuel being mixed into the lubricating oil in the cam chamber. There is.

  In order to achieve the above object, the invention according to claim 1 of the present application is directed to a fuel tank by a delivery valve that can be opened and closed by a vertical movement of a plunger that engages with a rotating camshaft by transmitting rotation of a drive shaft of a diesel engine. An injection in which the liquefied gas fuel in the oil sump chamber to which liquefied gas fuel (except DME) is supplied via a feed pipe is communicated with the fuel injection nozzle of the diesel engine by a predetermined amount at a predetermined timing. An injection pump of the liquefied gas fuel supply device of the diesel engine having an injection pump element that pressurizes and feeds to a pipe, wherein the injection pump element includes the plunger and the plunger from the oil reservoir chamber toward the cam chamber. Leak on the sliding contact surface with the inserted plunger barrel A liquefied gas fuel vaporization portion formed on a sliding contact surface between the plunger and the plunger barrel, wherein the liquid liquefied gas fuel is decompressed and vaporized before leaking into the cam chamber. This is an injection pump characterized by

  As described above, the oil reservoir chamber of the injection pump is filled with liquefied gas fuel in a high-pressure liquid state, and the liquefied gas fuel supplied from the oil reservoir chamber to each injection pump element is separated from the plunger by the pressure. A slight leak in the sliding contact surface with the plunger barrel will slightly leak into the cam chamber. Therefore, in this way, by providing a space for reducing the pressure of the liquefied gas fuel in a high-pressure liquid state leaking from the oil reservoir chamber on the sliding contact surface between the plunger and the plunger barrel, the property of becoming a gas at room temperature can be obtained. The liquefied gas fuel in a high-pressure liquid state that is contained can be vaporized before leaking into the cam chamber by reducing the pressure below the saturated vapor pressure.

  In other words, the liquefied gas fuel vaporization unit applies the principle of liquefied gas fuel that becomes a gas under atmospheric pressure at normal temperature by reducing the pressure when the liquid expands suddenly and losing its energy, The pressurized liquefied gas fuel in a liquid state is decompressed and vaporized. Accordingly, the liquefied gas fuel in the high-pressure liquid state in the oil reservoir chamber is vaporized by being depressurized in the space before leaking into the cam chamber from the sliding contact surface between the plunger and the plunger barrel. It can prevent mixing with the lubricating oil in a cam chamber.

  Thus, according to the injection pump according to the first aspect of the present invention, the liquefied gas fuel in the liquid state is supplied to the cam chamber by the liquefied gas fuel vaporizing portion having the space for decompressing the liquefied gas fuel in the high pressure liquid state. Therefore, it is possible to prevent deterioration in the lubricating performance of the lubricating oil due to the liquid liquefied gas fuel being mixed into the lubricating oil in the cam chamber. The effect is obtained.

  The invention according to claim 2 of the present application is the injection pump according to claim 1, wherein the space portion is formed by an annular groove formed in a circumferential direction on a peripheral surface of the plunger.

  According to the injection pump according to the second aspect of the present invention, in addition to the function and effect of the first aspect of the present invention, since the space portion of the liquefied gas fuel vaporization portion is formed in the plunger, Since the space part is formed in the outer peripheral surface of the plunger, the effect that the process for forming a space part becomes easy is acquired.

  The invention according to claim 3 of the present application is the injection pump according to claim 1, wherein the space portion is formed by an annular groove formed in a circumferential direction on an inner peripheral surface of the plunger barrel. is there.

  As described above, the space portion may be formed on the inner peripheral surface of the plunger barrel in which the outer peripheral surface of the plunger is in sliding contact, whereby the operation and effect of the invention of claim 1 can be obtained.

  The invention according to claim 4 of the present application is the injection pump according to claim 2 or 3, wherein the liquefied gas fuel vaporization section has a plurality of the annular grooves.

  In this way, a plurality of spaces are formed by forming the space portion by the plurality of annular grooves, whereby the high pressure liquid liquefied gas fuel can be decompressed stepwise. Therefore, since the volume of each space by the annular groove can be set small, the possibility that the accuracy of the sliding contact surface between the plunger and the plunger barrel formed with high accuracy may be reduced.

  Thereby, according to the injection pump which concerns on invention of Claim 4 of this application, in addition to the effect by the invention of Claim 2 or 3 of this application, the plunger and plunger barrel by forming a liquefied gas fuel vaporization part The effect of being able to reduce the influence on accuracy is obtained.

  The invention according to claim 5 of the present application is the liquefied gas fuel vaporization unit according to any one of claims 1 to 4, wherein the space portion is close to the cam chamber of the sliding contact surface between the plunger and the plunger barrel. The injection pump is characterized in that it is formed.

  The pressure of the high-pressure liquid liquefied gas fuel leaking to the sliding contact surface between the plunger and the plunger barrel gradually decreases in the process of leaking toward the cam chamber. Therefore, since the liquefied gas fuel vaporization part is formed closer to the cam chamber, the liquefied gas fuel in a state where the pressure has dropped to some extent is decompressed and vaporized, so that the liquefied gas fuel in the liquid state at high pressure is effectively decompressed. And can be vaporized.

  Thereby, according to the injection pump which concerns on invention of this-application Claim 5, in addition to the effect by the invention of any one of Claims 1-4 of this application, it leaks between a plunger and a plunger barrel. The effect of being able to effectively depressurize and vaporize the liquefied gas fuel in the liquid state at the high pressure that has come out is obtained.

Invention of Claim 6 of this application is the liquefied gas fuel supply apparatus of the diesel engine provided with the injection pump of any one of Claims 1-5.
According to the liquefied gas fuel supply device for a diesel engine according to the invention described in claim 6 of the present application, in the liquefied gas fuel supply device for the diesel engine, according to the invention described in any one of claims 1 to 5 of the present application described above. An effect can be obtained.

  According to the present invention, it is possible to prevent a decrease in the lubricating performance of the lubricating oil due to the liquid liquefied gas fuel being mixed into the lubricating oil in the cam chamber.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, a schematic configuration of a liquefied gas fuel supply device for a diesel engine will be described. FIG. 1 is a system configuration diagram showing a schematic configuration of a liquefied gas fuel supply device for a diesel engine according to the present invention.

  A DME fuel supply device 100 that supplies liquefied gas fuel to a diesel engine 200 includes an injection pump 1 according to the present invention. Here, a case where a high cetane number LP gas (LP gas added with a cetane number improver) having a cetane number of about 40 to 55, desirably 50 or more, is used as the liquefied gas fuel. Examples of the cetane number improver include known nitrate esters, nitrite esters and organic peroxides, and specifically DTBP (Di-tertiary butyl peroxide) or 2HEN (2-Ethylhexylnitrate). Further, since LP gas has lower lubricity than light oil, a known alkyl ester is added as a lubricity improver.

  The injection pump 1 includes the same number of injection pump elements 2 as the number of cylinders 31 included in the diesel engine 200. The feed pump 5 pressurizes the liquefied gas fuel stored in the fuel tank 4 to a predetermined pressure and sends it to the feed pipe 52. The liquefied gas fuel outlet of the fuel tank 4 is provided below the liquid level of the liquefied gas fuel in the fuel tank 4, and the feed pump 5 is disposed in the vicinity of the liquefied gas fuel outlet of the fuel tank 4. Yes. The liquefied gas fuel sent to the feed pipe 52 is filtered by the filter 51 and sent to the injection pump 1 via the three-way electromagnetic valve 71. The three-way solenoid valve 71 is in an ON state in the injection state (during the operation of the diesel engine 200) and communicates in the direction of the arrow indicated by the symbol A.

  The cam chamber (not shown) in the injection pump 1 is a dedicated lubrication system separated from the lubrication system of the diesel engine 200, and the oil separator 6 is liquefied gas leaking into the cam chamber in the injection pump 1. The lubricating oil in the cam chamber mixed with fuel is separated into liquefied gas fuel and lubricating oil, and the lubricating oil is returned to the cam chamber. The liquefied gas fuel separated by the oil separator 6 is sent to a compressor 61 driven by a cam in the cam chamber via a check valve 62 that prevents the pressure in the cam chamber from becoming atmospheric pressure or lower. After being pressurized, the fuel is returned to the fuel tank 4 through the check valve 63 and the cooler 41. The check valve 63 is provided to prevent the liquefied gas fuel from flowing backward from the fuel tank 4 to the cam chamber when the diesel engine 200 is stopped.

  Thus, since the cam chamber of the injection pump 1 is a dedicated lubrication system separated from the lubrication system of the diesel engine 200, the liquefied gas fuel leaked from the injection pump element 2 into the cam chamber is absorbed by the diesel engine 200. There is no risk of entering the lubrication system. Thereby, the risk that the liquefied gas fuel that has entered the lubrication system of the diesel engine 200 is vaporized and the vaporized liquefied gas fuel enters the crank chamber of the diesel engine 200 can be eliminated.

  The liquefied gas fuel pressurized from the fuel tank 4 to a predetermined pressure by the feed pump 5 and sent out from each injection pump element 2 of the injection pump 1 through the injection pipe 3 by a predetermined amount at a predetermined timing. It is pumped to a fuel injection nozzle 32 disposed in each cylinder 31 of the diesel engine 200. The liquefied gas fuel overflowed from the injection pump 1 is returned to the fuel tank 4 via the overflow fuel pipe 8 and the check valve 91 for determining the pressure of the overflow fuel and the cooler 41. The liquefied gas fuel that has overflowed from each fuel injection nozzle 32 is returned to the fuel tank 4 via the overflow fuel pipe 9 and the check valve 91 and the cooler 41 that determine the pressure of the overflow fuel.

  Furthermore, the liquefied gas fuel supply device 100 supplies the liquefied gas fuel remaining in the oil reservoir chamber (not shown), the overflow fuel pipe 8 and the overflow fuel pipe 9 in the injection pump 1 when the diesel engine 200 is stopped. The aspirator 7, the three-way solenoid valve 71, and the two-way solenoid valve 72 are provided as components of the “residual fuel recovery means” that recovers to the fuel tank 4.

  The aspirator 7 has an inlet 7a, an outlet 7b, and a suction port 7c. The inlet 7a and the outlet 7b communicate with each other in a straight line, and the suction port 7c branches off from the communication path between the inlet 7a and the outlet 7b in a substantially vertical direction. The outlet side of the communication path (communication direction indicated by the arrow B) connected to the three-way solenoid valve 71 is connected to the inlet 7a, and the outlet 7b is connected to the path to the fuel tank 4 via the cooler 41. It is connected. The suction port 7c is connected to a two-way electromagnetic valve 72 that is in an OFF state during an injection state (when the diesel engine 200 is in operation).

  In the non-injection state (when the diesel engine 200 is stopped), the three-way solenoid valve 71 is turned off to form a communication path in the direction indicated by the arrow B, and the two-way solenoid valve 72 is turned on. The overflow fuel pipe 8 and the overflow fuel pipe 9 are communicated with the suction port 7c of the aspirator 7 (in the direction indicated by the arrow C). Therefore, the liquefied gas fuel sent from the feed pump 5 is not sent to the injection pump 1 but sent to the aspirator 7, passes through the inlet 7 a to the outlet 7 b, returns to the fuel tank 4 through the cooler 41, and feeds again. It is sent from the pump 5 to the aspirator 7. That is, the liquefied gas fuel liquid circulates through the aspirator 7. The liquefied gas fuel remaining in the oil reservoir, the overflow fuel pipe 8, and the overflow fuel pipe 9 in the injection pump 1 is discharged from the suction port 7c by the flow of the liquefied gas fuel liquid flowing through the inlet 7a and the outlet 7b. It is sucked and collected in the fuel tank 4.

  As described above, the residual fuel recovery means sucks the liquefied gas fuel from the oil reservoir, the overflow fuel pipe 8 and the overflow fuel pipe 9 by the aspirator 7 using the feed pump 5 as a drive source and recovers it to the fuel tank 4. Therefore, it is not necessary to provide a new pump for collecting residual fuel.

  Next, the schematic structure of the injection pump element 2 constituting the injection pump 1 according to the present invention will be described. FIG. 2 is a perspective view of a main part showing a cross section in the vicinity of the injection pump element 2 of the injection pump 1 according to the present invention. 3 is a cross-sectional view of the injection pump 1 according to the present invention. FIG. 3 (a) is an overall side view, and FIG. 3 (b) is an enlarged view of a part of the plunger. is there.

  The delivery valve holder 21 has a shape having a delivery valve insertion hole 211 and is fixed to the base body of the injection pump 1. The injection pipe 3 is connected to the fuel liquid delivery port 212 communicating with the delivery valve insertion hole 211. The delivery valve 23 is inserted into the delivery valve insertion hole 211 so as to be able to reciprocate. The delivery valve 23 is provided integrally with the delivery valve holder 21 by the delivery spring 22. The valve portion 231 is urged so as to contact the valve seat portion 24a.

  The plunger barrel 25 is disposed integrally with the delivery valve seat 24 and has a hydraulic chamber 25 a communicating with the delivery valve seat 24. A plunger 26 is inserted into the hydraulic pressure chamber 25 a so as to be able to reciprocate, and one end side thereof faces the delivery valve 23. The plunger 26 is biased toward the cam 13 by a plunger spring 27. The plunger 26 is connected to the drive shaft of the diesel engine 200 and is driven by the cam 13 of the camshaft 12 rotated by the drive force of the diesel engine 200 via the tappet 28 (the direction indicated by the arrow D). Pushed up. The flange portion 261 of the plunger 26 is engaged with a sleeve 291 that is an integral cylindrical member with a pinion 29 that rotates by engaging with the control rack 14, and the pinion 29 is rotated by reciprocation of the control rack 14. The plunger 26 is configured to rotate in the circumferential direction, and the injection amount of the liquefied gas fuel increases or decreases depending on the rotation position of the plunger 26.

  Three annular grooves 20 as “liquefied gas fuel vaporization portions” according to the present invention are formed in the circumferential direction of the inner peripheral surface of the plunger barrel 25 on the inner peripheral surface of the plunger barrel 25 into which the plunger 26 is inserted. ing. A space 20 a is formed on the sliding contact surface between the plunger 26 and the plunger barrel 25 by the annular groove 20. When the liquefied gas fuel in a high-pressure liquid state in the oil reservoir chamber 11 is filled in the hydraulic pressure chamber 25a and the plunger 25 is raised and sent to the fuel liquid delivery port 212 via the delivery valve 23, the plunger 26 The liquefied gas fuel in a liquid state leaks to the sliding contact surface between the plunger barrel 25 and the plunger barrel 25. The liquefied gas fuel in a liquid state leaking to the sliding contact surface between the plunger 26 and the plunger barrel 25 leaks into the cam chamber 15 in a state where the pressure is gradually reduced and vaporized in the three space portions 20a. The liquefied gas fuel leaked into the cam chamber 15 in the vaporized state is separated from the lubricating oil by the oil separator 6 disposed in the cam chamber 15, sucked by the compressor 61, and sent to the fuel tank 4.

  The volume of the space portion 20a is such that the liquefied gas fuel in a liquid state leaking to the sliding contact surface between the plunger 26 and the plunger barrel 25 is sufficiently decompressed due to the distance between the sliding contact surfaces between the plunger 26 and the plunger barrel 25, Any capacity that can be vaporized is acceptable. Further, since the sliding contact surface between the plunger 26 and the plunger barrel 25 is formed with high accuracy, the width is as narrow as possible and the capacity is small in order to minimize the influence of the annular groove 20 on the accuracy. It can be said that a groove is preferable.

  In this way, the liquefied gas fuel in a high pressure and liquid state leaking from the oil reservoir chamber 11 toward the cam chamber 15 to the sliding contact surface between the plunger 26 and the plunger barrel 25 is depressurized and vaporized in the space portion 20a. In this state, it leaks into the cam chamber 15. Then, the liquefied gas fuel leaked into the cam chamber 15 is sucked by the compressor 61 while being separated by the oil separator 6 and returned to the fuel tank 4, so that the liquefied gas fuel leaks into the cam chamber 15 in the liquid state. Thus, it can be prevented that the oil is mixed into the lubricating oil in the cam chamber 15. Therefore, it is possible to reduce the possibility that the lubricating performance of the lubricating oil is deteriorated due to the liquefied gas fuel mixed in the lubricating oil.

  As another embodiment, an annular groove 20 forming the space 20a is formed near the cam chamber 15 on the sliding contact surface between the plunger 26 and the plunger barrel 25. FIG. 4 is an enlarged cross-sectional view of a part of the injection pump 1 in which the annular groove 20 is formed near the cam chamber 15 of the plunger barrel 25.

  The pressure of the high-pressure liquid liquefied gas fuel leaking to the sliding contact surface between the plunger 26 and the plunger barrel 25 gradually decreases in the process of leaking toward the cam chamber 15. Therefore, since the annular groove 20 is formed closer to the cam chamber 15 and the space portion 20a is formed closer to the cam chamber in this way, the liquefied gas fuel in a state where the pressure has decreased to some extent is reduced and vaporized. The liquefied gas fuel in a liquid state at high pressure can be effectively decompressed and vaporized.

  Furthermore, as other embodiment, what formed the annular groove 20 in the plunger 26 is mentioned. FIG. 5 is an enlarged sectional view showing a part of the injection pump 1 in which the annular groove 20 is formed in the plunger 26.

  Thus, even if the annular groove 20 is provided in the plunger 26 and the space portion 20a is formed on the sliding contact surface between the plunger 26 and the plunger barrel 25, the present invention can be implemented, and the effects of the present invention can be obtained. It is something that can be done. Further, by forming the annular groove 20 in the plunger 26, there is an advantage that the annular groove 20 can be easily formed with high accuracy.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

The present invention relates to an injection pump for a liquefied gas fuel supply device of a diesel engine using a liquefied gas such as LP gas (hereinafter referred to as “high cetane number LP gas”) or DME (dimethyl ether) to which a cetane number improver is added. And a liquefied gas fuel supply device for a diesel engine equipped with the injection pump.

1 is a system configuration diagram showing a schematic configuration of a liquefied gas fuel supply device for a diesel engine according to the present invention. It is the principal part perspective view which showed the cross section of the injection pump element vicinity of the injection pump which concerns on this invention. It is sectional drawing of the injection pump which concerns on this invention, FIG. 3 (a) is a whole side view, FIG.3 (b) expands and shows a part of plunger. It is sectional drawing which expanded and showed a part of injection pump in which the annular groove was formed near the cam chamber of a plunger barrel. It is sectional drawing which expanded and showed a part of injection pump in which the annular groove was formed in the plunger.

Explanation of symbols

1 injection pump, 2 injection pump elements,
6 oil separator, 11 oil reservoir, 15 cam chamber, 20 annular groove, 20a space,
25 plunger barrel, 26 plunger, 61 compressor,
100 liquefied gas fuel supply device, 200 diesel engine

Claims (6)

Liquefied gas fuel (excluding DME) is supplied from the fuel tank via the feed pipe by a delivery valve that can be opened and closed by the vertical movement of the plunger that engages with the rotating camshaft by transmitting the rotation of the drive shaft of the diesel engine. The liquefaction of the diesel engine having an injection pump element that pressurizes and sends out the liquefied gas fuel in the oil reservoir chamber to the injection pipe communicating with the fuel injection nozzle of the diesel engine by a predetermined amount at a predetermined timing An injection pump for a gas fuel supply device,
The injection pump element supplies liquid liquefied gas fuel leaked from the oil reservoir chamber toward the cam chamber into a sliding contact surface between the plunger and a plunger barrel into which the plunger is inserted. An injection pump characterized by comprising a liquefied gas fuel vaporizing portion formed on a sliding contact surface between the plunger and the plunger barrel, wherein a space portion that is decompressed and vaporized before leaking is formed.   2. The injection pump according to claim 1, wherein the space portion is formed by an annular groove formed in a circumferential direction on a peripheral surface of the plunger.   2. The injection pump according to claim 1, wherein the space portion is formed by an annular groove formed in a circumferential direction on an inner peripheral surface of the plunger barrel.   4. The injection pump according to claim 2, wherein the liquefied gas fuel vaporizing section has a plurality of the annular grooves.   5. The liquefied gas fuel vaporization unit according to claim 1, wherein the space is formed near the cam chamber on a sliding contact surface between the plunger and the plunger barrel. Injection pump.   The liquefied gas fuel supply apparatus of the diesel engine provided with the injection pump of any one of Claims 1-5.

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