Gas fuel injection valve

Abstract

To protect a seal member while ensuring the injection performance of gas fuel.SOLUTION: In a fuel injection valve, a nozzle body 12 has an end plate portion 33 that divides upstream and downstream fuel passages P1, P2, and a communication hole 34 is provided in the end plate portion 33 to provide communication between the fuel passages P1, P2. The fuel injection valve is provided with an upper stage opening / closing valve 13 that opens and closes the communication hole 34 from the upstream side, a lower stage opening / closing valve 14 that opens and closes the communication hole 34 from the downstream side, and a seal member 27 that seals the communication hole 34 between the upper stage opening / closing valve 13 and an end plate portion 33. The upper stage opening / closing valve 13 is driven to open by a coil 25, while the lower stage opening / closing valve 14 is opened when the pressure in the communication hole 34 becomes higher than the biasing force of a second spring 45. In addition, the fuel injection valve has a configuration in which gas fuel that flows out of the communication hole 34 and adiabatically expands when the lower stage opening / closing valve 14 is opened is collided with an extension portion extending downstream from the end plate portion 33, thereby cooling the extension portion.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The disclosure herein relates to gas fuel injectors. [Background technology]

[0002] As a gas fuel injection valve used in a direct injection gas engine, for example, a gas metering valve described in Patent Document 1 is known. In this gas metering valve, an actuator-driven valve member is provided with an elastomer seal member to suppress leakage of gas fuel, while the seal position of the valve member is set far away from the fuel outlet opening to suppress damage to the seal member due to heat and pressure generated during combustion in the gas engine. In addition, a check valve (passive open / close valve) that opens due to the pressure difference between the upstream and downstream sides is provided between the actuator-driven valve member and the outlet opening in the gas metering valve to suppress the flame and combustion pressure in the combustion chamber from propagating to the seal member. This is said to effectively protect the elastomer seal member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-513065 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in the above Patent Document 1 increases the distance between the valve member provided with the seal member and the check valve downstream thereof, and the volume between these valve members and the check valve is large. Therefore, it is considered that the closing response of the check valve is low when the upstream valve member is closed, and there is a concern that the reduced response will cause gas leakage from the fuel injection valve and, ultimately, abnormal combustion in the gas engine. However, on the other hand, if the upstream valve member having a sealing function is installed close to the check valve, there is a concern that the seal member of the valve member will be damaged by heat.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a gas fuel injection valve that can protect a sealing member while ensuring the injection performance of gas fuel. [Means for solving the problem]

[0006] The present disclosure relates to A gas fuel injection valve that directly injects gas fuel into a combustion chamber of an internal combustion engine, The fuel injection nozzle has a main body portion having a cylindrical shape, a fuel passage therein, and a nozzle hole at a tip portion thereof. the main body has a partition portion that partitions the fuel passage into a first fuel passage on an upstream side and a second fuel passage on a downstream side, and the partition portion is provided with a communication hole that communicates the first fuel passage with the second fuel passage, a first on-off valve that opens and closes the communication hole from the first fuel passage side, a second on-off valve that opens and closes the communication hole from the second fuel passage side, and a seal member that seals a periphery of an opening of the communication hole between the first on-off valve and the partition portion, the first on-off valve is driven to open by a drive unit, while the second on-off valve is opened when the pressure in the communication hole becomes higher than the biasing force of a biasing member that biases the second on-off valve to a valve closing side, The gas fuel that flows out of the communication hole and adiabatically expands as the second on-off valve opens is caused to collide with an extension portion extending downstream from the partition portion, thereby cooling the extension portion.

[0007] In the fuel injection valve having the above-mentioned configuration, the upstream side of the partitioning portion in the cylindrical main body portion is the first fuel passage, and the downstream side is the second fuel passage, and the first fuel passage and the second fuel passage are communicated with each other through a communication hole. Then, the communication hole is opened from the first fuel passage side as the drive portion drives the first on-off valve to open, and when the pressure in the communication hole increases due to the opening of the first on-off valve, the passive second on-off valve is opened, and the communication hole is also opened on the second fuel passage side. When the communication holes are opened on the upstream side and the downstream side, the gas fuel is injected from the fuel injection valve. In this case, a seal member that seals around the opening of the communication hole is provided between the first on-off valve and the partitioning portion, and it is possible to improve the gas sealing performance compared to a configuration in which the first on-off valve and the partitioning portion are in direct contact with each other when the first on-off valve is in a closed state.

[0008] In addition, when the gas fuel flows out of the communication hole with the opening of the second on-off valve, adiabatic expansion of the gas fuel occurs, and the gas fuel whose temperature has been reduced by the adiabatic expansion cools the partition. That is, the gas fuel that flows out of the communication hole with the opening of the second on-off valve and has been adiabatically expanded collides with the extension extending from the partition toward the downstream side, thereby cooling the extension, and further cooling the partition. Then, with the cooling of the extension, the seal member provided on the opposite side (the first on-off valve side) of the second on-off valve across the partition is cooled. In this case, the seal member is provided in a relatively close position to the second on-off valve, separated only by the partition, but an excessive temperature rise of the seal member is suppressed. In addition, since the upstream and downstream on-off valves are provided in a relatively close position with the partition between them, a decrease in responsiveness is suppressed in the passive second on-off valve. As a result, the injection performance of the gas fuel can be ensured while protecting the seal member. [Brief description of the drawings]

[0009] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] FIG. 4 is an enlarged vertical cross-sectional view showing a nozzle body and a lower stage on-off valve. [Figure 4]A cross-sectional view taken along line 4-4 in Figure 3. [Diagram 5] FIG. [Figure 6] FIG. 4 is a vertical cross-sectional view showing a fuel injection valve in an open state. [Figure 7] FIG. 11 is an enlarged longitudinal sectional view showing a nozzle body and a lower on-off valve in a further embodiment. [Figure 8] FIG. 11 is a vertical cross-sectional view showing the configuration of a fuel injection valve according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a gas fuel injection valve according to the present disclosure will be described with reference to the drawings. The gas fuel injection valve of this embodiment is applied to a direct injection gas engine (internal combustion engine) that uses any one of hydrogen, CNG (Compressed Natural Gas), and LNG (Liquefied Natural Gas) as gas fuel, and the gas fuel injection valve directly injects the gas fuel into the combustion chamber of the gas engine. The gas engine is, for example, an engine mounted on a vehicle. The fuel injection system of this embodiment is a so-called low-pressure direct injection system in which gas fuel compressed to about several MPa is injected into the combustion chamber from the fuel injection valve.

[0011] The configuration of the fuel injection valve 10 will be described with reference to Fig. 1. In the following description, the axis extending in the longitudinal direction of the fuel injection valve 10 and at the center of the cross section is taken as a reference, the direction in which the axis extends is taken as the axial direction, the direction extending radially from the axis is taken as the radial direction, and the direction extending circumferentially around the axis is taken as the circumferential direction. In Fig. 1, the right side is taken as the base end side (upstream side) of the fuel injection valve 10, and the left side is taken as the tip side (downstream side).

[0012] The fuel injection valve 10 generally includes a housing 11, a nozzle body 12 located at the tip side of the housing 11, an upper stage opening / closing valve 13 provided in the housing 11 so as to be capable of reciprocating motion, and a lower stage opening / closing valve 14 provided in the nozzle body 12 so as to be capable of reciprocating motion. The upper stage opening / closing valve 13 is an active type upstream opening / closing valve that opens by electromagnetic drive, and the lower stage opening / closing valve 14 is a passive type downstream opening / closing valve that opens by a pressure difference between the upstream side and the downstream side. In the fuel injection valve 10, the lower stage opening / closing valve 14 opens in response to the opening of the upper stage opening / closing valve 13, and gas fuel is injected from a nozzle hole 15 by the opening of the opening / closing valves 13, 14. The housing 11 and the nozzle body 12 correspond to a "main body", the upper stage opening / closing valve 13 corresponds to a "first opening / closing valve", and the lower stage opening / closing valve 14 corresponds to a "second opening / closing valve".

[0013] Although not shown because it is a known configuration, the fuel injection valve 10 is attached to the gas engine so that its tip (nozzle body 12) is exposed inside the combustion chamber, and the fuel injection valve 10 directly injects gas fuel into the combustion chamber. The configuration of each part of the fuel injection valve 10 will be described in detail below.

[0014] The housing 11 is formed in a cylindrical shape, and a fixed core 21 is fixed in its hollow portion, and the upper stage opening / closing valve 13 is accommodated in a reciprocating state at a position aligned with the fixed core 21 in the axial direction. The upper stage opening / closing valve 13 is made of a movable core. The fixed core 21 is cylindrical, and a first spring 22 made of a compression coil spring is arranged inside the fixed core 21. The first spring 22 is provided between a spring receiving portion 21a of the fixed core 21 and an axial end face of the upper stage opening / closing valve 13. The first spring 22 biases the upper stage opening / closing valve 13 toward the tip side of the fuel injection valve 10 (i.e., in a direction to close a communication hole 34 described later from the base end side).

[0015] The fixed core 21 has a hollow portion 21b, and the upper stage on-off valve 13 has a hollow portion 13a. These hollow portions 21b, 13a extend in the axial direction and communicate with each other. When gas fuel is supplied from a fuel pipe provided on the base end side of the fixed core 21, the gas fuel is introduced to the tip side of the upper stage on-off valve 13 through an upstream fuel passage P1 consisting of the hollow portions 21b, 13a of the fixed core 21 and the upper stage on-off valve 13. In this embodiment, for example, hydrogen gas is used as the gas fuel, and the gas fuel compressed to about 3 MPa is introduced into the fuel passage P1.

[0016] Further, a coil 25 is provided in the housing 11 as a drive unit for the fuel injection valve 10. An energization signal is input to the coil 25 from a power supply device (not shown) via a harness 26. When the coil 25 is energized, magnetic energy is generated, and the upper opening / closing valve 13 is displaced to the valve opening side against the biasing force of the first spring 22 by the magnetic energy.

[0017] The nozzle body 12 is provided downstream of the upper stage on-off valve 13. The nozzle body 12 has a first cylindrical portion 31 at the tip end and a second cylindrical portion 32 at the base end, and the inner circumferential sides of these cylindrical portions 31, 32 form a downstream fuel passage P2. One axial end of the first cylindrical portion 31 forms the injection hole 15. The second cylindrical portion 32 has an end plate portion 33 provided at the base end end. The end plate portion 33 has a plurality of communication holes 34 extending in the axial direction. The end plate portion 33 is a partition portion that partitions the upstream fuel passage P1 formed by the fixed core 21 and the upper stage on-off valve 13 and the downstream fuel passage P2 formed by the nozzle body 12 in the fuel injection valve 10, and the communication hole 34 is a communication passage that communicates the upstream and downstream fuel passages P1, P2. The end plate portion 33 is a pressure partition that prevents the pressure generated by the combustion in the engine combustion chamber from being transmitted to the upstream fuel passage P1.

[0018] Fig. 2 is a perspective view of the second tubular portion 32. As shown in Fig. 2, the second tubular portion 32 is provided with a peripheral wall portion 35 extending toward the downstream side (the left side in the figure) on the outer periphery of the end plate portion 33. The end plate portion 33 is provided with a plurality of communication holes 34 circumferentially arranged along the peripheral wall portion 35. Each of the communication holes 34 is formed in an arc shape extending in the circumferential direction. However, the opening shape of each communication hole 34 may be any shape, and may be, for example, a circular opening shape.

[0019] Returning to the explanation of FIG. 1, a ring-shaped seal member 27 is fixed to the axial end face of the upper stage opening / closing valve 13 at a position facing the opening of each communication hole 34. When the upper stage opening / closing valve 13 is closed by the biasing force of the first spring 22 (the state of FIG. 1), the seal member 27 abuts against the seat surface 33a which is the axial end face of the end plate portion 33, and the seal member 27 closes the first opening which is the upstream opening of the communication hole 34. When the upper stage opening / closing valve 13 is displaced to the valve opening side, the seal member 27 separates from the seat surface 33a of the end plate portion 33, and the first opening is opened. The seal member 27 is made of any of elastic materials having elasticity such as rubber, resin, elastomer, etc., and more specifically, fluororubber, EPDM (ethylene propylene diene rubber), etc. may be used as the seal material.

[0020] The nozzle body 12 is provided with a lower stage opening / closing valve 14 for opening and closing the communication hole 34 from the fuel passage P2 side. The lower stage opening / closing valve 14 has a cylindrical portion 41 and a flange-shaped opening closing portion 42 that is provided on one axial end side of the cylindrical portion 41 and extends in the radial direction. The cylindrical portion 41 is a sliding portion that can slide in the axial direction along the inner circumferential surface of the first tubular portion 31, and the opening closing portion 42 is a closing plate portion that closes the second opening, which is the downstream opening of the communication hole 34. The opening closing portion 42 is capable of lifting between a position for closing the second opening (downstream opening) of the communication hole 34 and a position for opening it. In this embodiment, the opening closing portion 42 is in the shape of an annular plate and is provided in a direction extending radially outward from the cylindrical portion 41.

[0021] A second spring 45 made of a compression coil spring is disposed between the opening closing portion 42 and the axial end face of the first cylindrical portion 31. The second spring 45 biases the lower stage opening / closing valve 14 toward the base end side of the fuel injection valve 10 (i.e., in a direction to close the communication hole 34 from the tip end side). The lower stage opening / closing valve 14 opens when the pressure in the communication hole 34 becomes greater than the biasing force of the second spring 45. The second spring 45 corresponds to the "biasing member."

[0022] The lower on-off valve 14 may be made of a metal material, a nonmetal material, or other non-elastomer material having excellent heat resistance. The opening closing portion 42 is pressed against the downstream opening of the communication hole 34, thereby suppressing leakage of gas fuel from the communication hole 34 and also suppressing the inflow of flames and combustion pressure into the combustion chamber.

[0023] In the end plate portion 33, the communication hole 34 is closed from the fuel passage P1 side, which is one axial side, by the upper stage on-off valve 13, and the communication hole 34 is closed from the fuel passage P2 side, which is the other axial side, by the lower stage on-off valve 14. The upper stage on-off valve 13 is an inward opening valve that opens on the base end side of the fuel injection valve 10, and the lower stage on-off valve 14 is an outward opening valve that opens on the tip side of the fuel injection valve 10.

[0024] In the fuel injection valve 10, when the upper on-off valve 13 is displaced to the valve opening side as a result of energization of the coil 25, the gas fuel in the upstream fuel passage P1 flows into the communication hole 34, and the pressure in the communication hole 34 rises. Then, when the pressure in the communication hole 34 exceeds the biasing force of the second spring 45, the lower on-off valve 14 is displaced to the valve opening side. In this case, when the on-off valves 13, 14 on both sides of the communication hole 34 are both in the open state, the gas fuel flows from the upstream fuel passage P1 to the downstream fuel passage P2, and the gas fuel is further injected from the nozzle hole 15 at the tip of the fuel passage P2.

[0025] In the fuel injection valve 10 of this embodiment, after the upper stage on-off valve 13 is closed, gas fuel remains in the communication hole 34 provided in the end plate portion 33 until the upper stage on-off valve 13 is opened again. In this case, the total volume of the multiple communication holes 34 provided in the end plate portion 33 is the residual gas volume remaining downstream of the upper stage on-off valve 13 after the upper stage on-off valve 13 is closed, until the upper stage on-off valve 13 is opened again.

[0026] Next, a configuration regarding the outflow of gas fuel from the communication hole 34 when the lower stage on-off valve 14 is opened will be described in detail. Fig. 3 is an enlarged longitudinal sectional view showing the nozzle body 12 and the lower stage on-off valve 14, and Fig. 4 is a transverse sectional view taken along line 4-4 in Fig. 3. In Fig. 4, the communication hole 34 of the end plate portion 33 is shown by a dashed line. Fig. 5 is a perspective view of the lower stage on-off valve 14.

[0027] As shown in FIG. 3, in the nozzle body 12, the inner periphery of the first cylindrical portion 31 is formed with a sliding surface 36 for sliding the cylindrical portion 41 of the lower stage opening / closing valve 14, and the inner periphery of the first cylindrical portion 31 and the second cylindrical portion 32 is formed with an expanded inner periphery 37 having a larger diameter than the sliding surface 36. As a result, the inner periphery of the peripheral wall portion 35 becomes an expansion space S1 expanded radially outward at the most upstream portion of the fuel passage P2 (i.e., a predetermined range on the most upstream side). In other words, the passage diameter dimension is different between the most upstream portion of the fuel passage P2 and its downstream side in the nozzle body 12, and the passage diameter dimension is expanded at the most upstream portion to form an annular expansion space S1. In terms of the relationship with the lower stage opening / closing valve 14, the expansion space S1 is formed radially outward of the cylindrical portion 41.

[0028] The second spring 45 is housed in the expansion space S1. The expanded inner circumferential surface 37 and the expansion space S1 formed by the expanded inner circumferential surface 37 may be formed by the first cylindrical portion 31 and the second cylindrical portion 32, or may be formed by only the second cylindrical portion 32, so long as the expanded inner circumferential surface 37 is located downstream of the end plate portion 33 in the nozzle body 12.

[0029] Further, a protrusion 38 is provided at the center of the downstream end face of the end plate portion 33, protruding toward the downstream side. The protrusion 38 is provided on the radially inner side of the peripheral wall portion 35, and more specifically, on the radially inner side of the peripheral wall portion 35, on the radially inner side of the cylindrical portion 41 of the lower on-off valve 14. The protrusion 38 is formed in a cone shape. However, the shape of the protrusion 38 is arbitrary, and may be a cylinder, a prism, a pyramid, or the like, and a plurality of protrusions 38 may be provided. The peripheral wall portion 35 and the protrusion 38 correspond to the "extension portion."

[0030] Here, as shown in FIG. 4, if the outer diameter dimension of the cylindrical portion 41 of the lower stage opening / closing valve 14 (in other words, the inner diameter dimension of the sliding surface 36 of the first cylindrical portion 31) is D1, the inner diameter dimension of the expanded inner circumferential surface 37 is D2, and the outer diameter dimension of the opening / closing portion 42 of the lower stage opening / closing valve 14 is D3, then each of these dimensions is expressed as D1.<D3、D2> In other words, the inside diameter dimension D2 of the expanded inner circumferential surface 37 is larger than the outside diameter dimension D1 (the inside diameter dimension of the sliding surface 36) of the cylindrical portion 41, thereby forming an expanded space S1. Also, the inside diameter dimension D2 of the expanded inner circumferential surface 37 is larger than the outside diameter dimension D3 of the opening closing portion 42, thereby making it possible to form a radial gap between the expanded inner circumferential surface 37 and the outer periphery of the opening closing portion 42.

[0031] Therefore, when the lower stage opening / closing valve 14 is displaced to the open position, the gas fuel flowing out from the communication hole 34 to the downstream side flows along the radially outer side and the radially inner side through the gap between the downstream end face of the end plate portion 33 and the opening closing portion 42. That is, the opening closing portion 42 has a portion protruding radially outward from the opening of the communication hole 34 and a portion protruding radially inward, and these protruding portions guide the gas fuel flowing out from the communication hole 34 to the radially inner side and the radially outer side, respectively. The opening closing portion 42 corresponds to a "guide portion." At this time, the gas fuel flowing in the radially outer direction advances so as to collide with the expanded diameter inner circumferential surface 37 (the inner circumferential surface of the peripheral wall portion 35) and is introduced into the expansion space S1 through the gap between the expanded diameter inner circumferential surface 37 and the outer circumferential portion of the opening closing portion 42. The gas fuel flowing in the radially inner direction advances so as to collide with the protruding portion 38 of the end plate portion 33.

[0032] Further, a plurality of openings 43 are provided at predetermined intervals in the circumferential direction in the cylindrical portion 41 of the lower on-off valve 14 (see FIG. 5). Therefore, the openings 43 are configured to communicate with the inside and outside of the cylindrical portion 41, i.e., the expansion space S1 and the inner space located radially inside the expansion space S1.

[0033] Fig. 6 is a diagram for explaining the flow of gas fuel when the fuel injection valve 10 is open. In Fig. 6, in the fuel injection valve 10, both the upper stage opening / closing valve 13 and the lower stage opening / closing valve 14 are in an open state, and the flow of gas fuel is indicated by arrows.

[0034] When the opening closing portion 42 moves away from the downstream end face (downstream seat face) of the end plate portion 33 during the opening of the lower stage opening / closing valve 14, the gas fuel flows out from the communication hole 34, and at that time, the temperature of the gas fuel drops due to adiabatic expansion of the gas fuel. Specifically, in a gas engine, the gas fuel is injected from the fuel injection valve 10 during at least one of the intake stroke and the compression stroke, and at the time of fuel injection, when the gas fuel flows out from the communication hole 34 as the lower stage opening / closing valve 14 opens, the gas fuel is decompressed from several MPa to near atmospheric pressure. For example, when the gas supply pressure is 2 MPa or more, it is considered that the gas temperature drops by 100°C or more due to adiabatic expansion.

[0035] The gas fuel flowing out from the communication hole 34 hits the flat opening closing portion 42, and flows down while being divided into the radially outward and radially inward directions. That is, the gas fuel flowing out from the communication hole 34 is guided radially outward and radially inward by the opening closing portion 42 of the lower stage opening / closing valve 14. The gas fuel guided radially outward collides with the inner circumferential surface of the peripheral wall portion 35, and then flows downstream in the fuel passage P2 via the expansion space S1 and the opening 43 of the lower stage opening / closing valve 14. At this time, the gas fuel whose temperature has been reduced by adiabatic expansion when flowing out from the communication hole 34 is introduced into the expansion space S1, and heat exchange in the expansion space S1 is promoted. This promotes cooling of the end plate portion 33, and suppresses a temperature rise of the seal member 27. In particular, the gas fuel is guided radially outward immediately after flowing out from the communication hole 34, and then the flow direction changes to the radially inward direction, and the course of the gas fuel meanders in the radial direction. Therefore, heat exchange with the second cylindrical portion 32 is promoted.

[0036] In addition, the second spring 45 is provided in the expansion space S1, and the second spring 45 is cooled by the gas fuel whose temperature has been reduced by adiabatic expansion. This makes it possible to reduce the thermal load on the second spring 45 exposed to the flames in the engine combustion chamber.

[0037] In addition, the gas fuel guided radially inward after the lower on-off valve 14 opens collides with the protruding portion 38 at the center of the end plate portion 33. As a result, the end plate portion 33 is cooled by the adiabatically expanded gas fuel, and the temperature rise of the seal member 27 is suppressed.

[0038] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0039] In the fuel injection valve 10, a seal member 27 that seals around the opening of the communication hole 34 is provided between the upper stage on-off valve 13 and the end plate portion 33. This makes it possible to improve the gas sealing performance compared to a configuration in which the upper stage on-off valve 13 and the end plate portion 33 are in direct contact when the upper stage on-off valve 13 is in a closed state.

[0040] In addition, when the gas fuel flows out from the communication hole 34 with the opening of the lower stage on-off valve 14, adiabatic expansion of the gas fuel occurs, and the end plate portion 33 is cooled by the gas fuel whose temperature has been reduced by the adiabatic expansion. With the cooling of the end plate portion 33, the seal member 27 provided on the opposite side (the upper stage on-off valve 13 side) of the lower stage on-off valve 14 across the end plate portion 33 is cooled. In this case, the seal member 27 is provided in a relatively close position to the lower stage on-off valve 14, separated only by the end plate portion 33, but an excessive temperature rise of the seal member 27 is suppressed. In addition, since the upstream and downstream on-off valves 13, 14 are provided in a relatively close position across the end plate portion 33, a decrease in responsiveness is suppressed in the passive type lower stage on-off valve 14. As a result, the seal member 27 can be protected while ensuring the injection performance of the gas fuel.

[0041] A communication hole 34 is provided between the peripheral wall portion 35 and the protruding portion 38 in the end plate portion 33 of the second cylindrical portion 32, and the opening closing portion 42 of the lower opening / closing valve 14 guides the gas fuel that flows out of the communication hole 34 and is adiabatically expanded radially outward and radially inward, respectively, and causes it to collide with the peripheral wall portion 35 and the protruding portion 38. In this case, the gas fuel whose temperature has been reduced by the adiabatic expansion collides with the peripheral wall portion 35 and the protruding portion 38, respectively, to cool the second cylindrical portion 32. This promotes cooling of the end plate portion 33 and suppresses a rise in temperature of the seal member 27.

[0042] According to the configuration of this embodiment, the desired cooling effect is achieved by optimizing the flow direction of the cooling gas (gas fuel after adiabatic expansion) using the lower on-off valve 14, and the sealing member 27 can be properly cooled while using a simple configuration.

[0043] In the nozzle body 12, a circular expansion space S1 is formed by expanding the passage diameter dimension at the most upstream side of the fuel passage P2, and the opening closing portion 42 of the lower stage on-off valve 14 guides the gas fuel flowing out from the communication hole 34 toward the expansion space S1. In this case, the gas fuel whose temperature has been reduced by adiabatic expansion when the lower stage on-off valve 14 is opened is introduced into the expansion space S1, and heat exchange within the expansion space S1 is promoted. This promotes cooling of the end plate portion 33, and suppresses a temperature rise of the seal member 27.

[0044] The cylindrical portion 41 of the lower stage on-off valve 14 is provided with an opening 43 that communicates with the expansion space S1 and an inner space located radially inside the expansion space S1. In this case, the gas fuel whose temperature has been reduced by adiabatic expansion when the lower stage on-off valve 14 is opened flows in such a way that the gas fuel is introduced into the expansion space S1 and then proceeds to the inner space via the opening 43 of the cylindrical portion 41. This allows the gas fuel to meander radially in the fuel passage P2, facilitating heat exchange with the second cylindrical portion 32.

[0045] A second spring 45 that biases the lower on-off valve 14 to the valve closing side is provided in the expansion space S1. In this case, the second spring 45 is cooled by the gas fuel whose temperature has been reduced by adiabatic expansion. This makes it possible to reduce the thermal load on the second spring 45 that is exposed to the flames in the engine combustion chamber.

[0046] The total volume of the multiple communication holes 34 provided in the end plate portion 33 of the second cylindrical portion 32 is the residual gas volume remaining downstream of the upper stage on-off valve 13 from when the upper stage on-off valve 13 is closed until when the upper stage on-off valve 13 is opened again. In other words, the end plate portion 33 only needs to have a plate thickness that divides the upstream and downstream fuel passages P1, P2 and can withstand pressure waves from the engine combustion chamber, and only the volume of the communication holes 34 according to the plate thickness is the residual gas volume downstream of the upper stage on-off valve 13. In this case, unlike an existing separate structure in which a spring or the like is interposed between the upper stage on-off valve 13 and the lower stage on-off valve 14, it is possible to reduce the residual gas volume and thereby improve the responsiveness of the fuel injection valve 10.

[0047] (Other embodiments) The above embodiment may be modified, for example, as follows.

[0048] In the above embodiment, the peripheral wall portion 35 and the protruding portion 38 of the nozzle body 12 are the objects (extending portions) against which the gas fuel after adiabatic expansion collides, but this configuration may be changed. For example, only the peripheral wall portion 35 may be the object (extending portion) against which the gas fuel after adiabatic expansion collides. Specifically, as shown in FIG. 7, the opening closing portion 42 of the lower stage opening / closing valve 14 is made to have a disk shape without an opening in the center, and the protruding portion 38 of the end plate portion 33 is deleted. In this case, the opening closing portion 42 of the lower stage opening / closing valve 14 guides the gas fuel that has flowed out of the communication hole 34 and has expanded adiabatically toward the outside in the radial direction and collides with the peripheral wall portion 35. As a result, the peripheral wall portion 35 and the end plate portion 33 are cooled, and the temperature rise of the seal member 27 is suppressed.

[0049] The fuel injection valve 10 may be configured as shown in Fig. 8. In Fig. 8, the main body is a cylindrical body, and an end plate portion 33 (partition portion) is fixed to the middle portion. Fig. 8 shows a state in which the upper stage opening / closing valve 13 and the lower stage opening / closing valve 14 are both open.

[0050] In FIG. 8, a communication hole 34 is provided in the center of the disk-shaped end plate portion 33, and the communication hole 34 is opened and closed by the upper stage opening / closing valve 13 from the upstream side, and is opened and closed by the lower stage opening / closing valve 14 from the downstream side. The lower stage opening / closing valve 14 is biased by a second spring 45 in a direction to close the downstream opening of the communication hole 34. In this configuration, as in the above, the lower stage opening / closing valve 14 guides the gas fuel that flows out from the communication hole 34 and adiabatically expands toward the outside in the radial direction, and the end plate portion 33 is cooled together with the peripheral wall portion 35 by the collision between the gas fuel and the peripheral wall portion 35, thereby suppressing the temperature rise of the seal member 27. Note that the surface of the lower stage opening / closing valve 14 facing the end plate portion 33 corresponds to the "guide portion."

[0051] In the above embodiment, the seal member 27 is provided between the upper stage opening / closing valve 13 and the end plate portion 33 by fixing the seal member 27 to the axial end face of the upper stage opening / closing valve 13, but this may be modified. For example, the seal member 27 may be fixed to the end plate portion 33 side.

[0052] As a drive unit for driving the upper stage opening / closing valve 13, a motor may be used instead of the coil 25.

[0053] The technical ideas extracted from the above-described embodiments will be described below. [Configuration 1] A gas fuel injection valve (10) that directly injects gas fuel into a combustion chamber of an internal combustion engine, The nozzle includes a main body (11, 12) having a cylindrical shape, a fuel passage therein, and a nozzle hole (15) at a tip end thereof, the main body portion has a partition portion (33) that partitions the fuel passage into a first fuel passage (P1) on an upstream side and a second fuel passage (P2) on a downstream side, and the partition portion is provided with a communication hole (34) that communicates the first fuel passage with the second fuel passage, a first on-off valve (13) for opening and closing the communication hole from the first fuel passage side, a second on-off valve (14) for opening and closing the communication hole from the second fuel passage side, and a seal member (27) for sealing a periphery of an opening of the communication hole between the first on-off valve and the partition portion are provided in the main body, The first on-off valve is driven to open by a drive unit (25), while the second on-off valve is opened when the pressure in the communication hole becomes higher than the biasing force of a biasing member (45) which biases the second on-off valve to a closing side. The gas fuel injection valve has a configuration in which gas fuel that flows out of the communication hole and adiabatically expands as the second opening / closing valve is opened is collided with an extension portion (35, 38) extending downstream from the partition portion, thereby cooling the extension portion. [Configuration 2] the main body portion has a peripheral wall portion (35) extending downstream from an outer periphery of the partition portion and forming the second fuel passage, and a protruding portion (38) protruding downstream from a downstream end surface of the partition portion at a position radially inward of the peripheral wall portion, the peripheral wall portion and the protruding portion being the extension portion, The partition portion has the communication hole between the peripheral wall portion and the protruding portion, 2. The gas fuel injection valve according to claim 1, wherein the second opening / closing valve has a guide portion (42) that guides the gas fuel that has flowed out of the communication hole and has been adiabatically expanded radially outward and radially inward, respectively, and causes the gas fuel to collide with the peripheral wall portion and the protruding portion. [Configuration 3] the main body portion has a peripheral wall portion (35) that extends downstream from an outer periphery of the partition portion and forms the second fuel passage, the peripheral wall portion being the extension portion, 2. The gas fuel injection valve according to claim 1, wherein the second opening / closing valve has a guide portion (42) that guides the gas fuel that has flowed out of the communication hole and has been adiabatically expanded radially outward and causes it to collide with the peripheral wall portion. [Configuration 4] a passage diameter dimension differs between an upstream-most portion and a downstream side of the second fuel passage in the main body, and the passage diameter dimension is expanded in the upstream-most portion to form an annular expansion space (S1), 4. The gas fuel injection valve according to claim 2, wherein the guide portion of the second opening / closing valve guides the gas fuel that has flowed out of the communication hole and has been adiabatically expanded radially outward and introduces it into the expansion space. [Configuration 5] the second on-off valve has a cylindrical portion (41) that is slidable along an inner circumferential surface of the main body portion, and the expansion space is formed on the radially outer side of the cylindrical portion, 5. The gas fuel injection valve according to claim 4, wherein the cylindrical portion has an opening (43) that communicates the expansion space with an inner space located radially inside the expansion space. [Configuration 6] 6. The gas fuel injection valve according to configuration 4 or 5, wherein a biasing member (45) that biases the second on-off valve to a valve closing side is provided in the expansion space. [Configuration 7] A gas fuel injection valve as described in any one of configurations 1 to 6, wherein a total volume of the multiple communicating holes provided in the partition portion is a residual gas volume remaining downstream of the first on-off valve after the first on-off valve is closed until the first on-off valve is opened again. [Explanation of symbols]

[0054] 10... fuel injection valve, 11... housing, 12... nozzle body, 13... upper stage opening / closing valve, 14... lower stage opening / closing valve, 15... injection hole, 25... coil, 27... sealing member, 33... end plate portion, 34... communication hole, 35... peripheral wall portion, 38... protrusion, P1, P2... fuel passage.

Claims

1. A gas fuel injection valve (10) for directly injecting gas fuel into a combustion chamber of an internal combustion engine, The nozzle includes a main body (11, 12) having a cylindrical shape, a fuel passage therein, and a nozzle hole (15) at a tip end thereof. the main body portion has a partition portion (33) that partitions the fuel passage into a first fuel passage (P1) on an upstream side and a second fuel passage (P2) on a downstream side, and the partition portion is provided with a communication hole (34) that communicates the first fuel passage with the second fuel passage, a first on-off valve (13) for opening and closing the communication hole from the first fuel passage side, a second on-off valve (14) for opening and closing the communication hole from the second fuel passage side, and a seal member (27) for sealing a periphery of an opening of the communication hole between the first on-off valve and the partition portion are provided within the main body, The first on-off valve is driven to open by a drive unit (25), while the second on-off valve is opened when the pressure in the communication hole becomes higher than the biasing force of a biasing member (45) that biases the second on-off valve to a valve closing side. a gas fuel injection valve configured to cause gas fuel that flows out of the communicating hole and adiabatically expands when the second opening / closing valve is opened to collide with an extension portion (35, 38) extending downstream from the partition portion, thereby cooling the extension portion.

2. the main body portion has a peripheral wall portion (35) extending downstream from an outer periphery of the partition portion and forming the second fuel passage, and a protruding portion (38) protruding downstream at a position radially inward of the peripheral wall portion on a downstream end surface of the partition portion, the peripheral wall portion and the protruding portion being the extension portion, The partition portion has the communication hole between the peripheral wall portion and the protruding portion, 2. The gas fuel injection valve according to claim 1, wherein the second opening / closing valve has a guide portion (42) that guides the gas fuel that has flowed out of the communication hole and has been adiabatically expanded radially outward and radially inward, respectively, and causes the gas fuel to collide with the peripheral wall portion and the protruding portion.

3. the main body portion has a peripheral wall portion (35) that extends downstream from an outer periphery of the partition portion and forms the second fuel passage, the peripheral wall portion being the extension portion, 2. The gas fuel injection valve according to claim 1, wherein the second opening / closing valve has a guide portion that guides the gas fuel that has flowed out of the communication hole and has been adiabatically expanded radially outward and causes it to collide with the peripheral wall portion.

4. a passage diameter dimension of the second fuel passage differs between an upstream-most portion and a downstream side thereof in the main body, and the passage diameter dimension is expanded in the upstream-most portion to form an annular expansion space (S1), 4. The gas fuel injection valve according to claim 2, wherein the guide portion of the second on-off valve guides the gas fuel that has flowed out of the communication hole and has been adiabatically expanded radially outward and introduces it into the expansion space.

5. The second on-off valve has a cylindrical portion (41) that is slidable against an inner circumferential surface of the main body portion, and the expansion space is formed on the radially outer side of the cylindrical portion, 5. The gas fuel injection valve according to claim 4, wherein the cylindrical portion has an opening (43) that communicates the expansion space with an inner space located radially inside the expansion space.

6. 5. The gas fuel injection valve according to claim 4, wherein a biasing member (45) for biasing the second opening / closing valve to a valve closing side is provided in the expansion space.

7. 2. A gas fuel injection valve as described in claim 1, wherein a total volume of the multiple communicating holes provided in the partition portion is a residual gas volume remaining downstream of the first opening / closing valve after the first opening / closing valve is closed until the next time the first opening / closing valve is opened.

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