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JP-7856066-B2 - Gas fuel injection valve

JP7856066B2JP 7856066 B2JP7856066 B2JP 7856066B2JP-7856066-B2

Inventors

  • 古川 隆

Assignees

  • 株式会社デンソー

Dates

Publication Date
20260511
Application Date
20230803

Claims (6)

  1. A gas fuel injection valve (10) that directly injects gaseous fuel into the combustion chamber of an internal combustion engine, It comprises a cylindrical body (11, 12) having a fuel passage inside and a nozzle (15) at its tip, The main body has a partition (33) that divides the fuel passage into an upstream first fuel passage (P1) and a downstream second fuel passage (P2), and the partition is provided with a communication hole (34) that connects the first fuel passage and the second fuel passage. The main body is provided with a first on-off valve (13) that opens and closes the communication hole from the first fuel passage side, a second on-off valve (14) that opens and closes the communication hole from the second fuel passage side, and a sealing member (27) that seals the area around the opening of the communication hole between the first on-off valve and the compartment. The first on-off valve is driven to open by the drive unit (25), while the second on-off valve opens when the pressure in the communication hole becomes higher than the biasing force of the biasing member (45) that biases the second on-off valve to the closed side. The system has a configuration in which the gas fuel that flows out from the communication hole and undergoes adiabatic expansion upon opening of the second on-off valve collides with the extensions (35, 38) that extend downstream from the compartment, thereby cooling the extensions . Furthermore, the main body portion has a peripheral wall portion (35) that extends downstream from the outer periphery of the compartment portion and forms the second fuel passage, and a projection portion (38) that protrudes downstream at a position on the downstream end face of the compartment portion that is radially inward of the peripheral wall portion, and these peripheral wall portion and projection portion constitute the extension portion. The partitioned portion is provided with the communication hole between the peripheral wall portion and the protruding portion. The second on-off valve is a gas fuel injection valve having a guide portion (42) that guides the gas fuel that flows out from the communication hole and undergoes adiabatic expansion radially outward and radially inward, respectively, and causes it to collide with the peripheral wall portion and the protruding portion .
  2. In the main body, the diameter of the second fuel passage differs between the uppermost part and the downstream side, and the passage diameter is expanded in the uppermost part to form an annular expansion space (S1). The gas fuel injection valve according to claim 1 , wherein the guide portion of the second on-off valve guides the gas fuel that flows out from the communication hole and undergoes adiabatic expansion radially outward and introduces it into the expanded space.
  3. The second on-off valve has a cylindrical portion (41) that is slidable against the inner circumferential surface of the main body, and the expansion space is formed radially outward of the cylindrical portion. The gas fuel injection valve according to claim 2 , wherein the cylindrical portion has an opening (43) that communicates the expanded space with an inner space radially inside it.
  4. A gas fuel injection valve (10) that directly injects gaseous fuel into the combustion chamber of an internal combustion engine, It comprises a cylindrical body (11, 12) having a fuel passage inside and a nozzle (15) at its tip, The main body has a partition (33) that divides the fuel passage into an upstream first fuel passage (P1) and a downstream second fuel passage (P2), and the partition is provided with a communication hole (34) that connects the first fuel passage and the second fuel passage. The main body is provided with a first on-off valve (13) that opens and closes the communication hole from the first fuel passage side, a second on-off valve (14) that opens and closes the communication hole from the second fuel passage side, and a sealing member (27) that seals the area around the opening of the communication hole between the first on-off valve and the compartment. The first on-off valve is driven to open by the drive unit (25), while the second on-off valve opens when the pressure in the communication hole becomes higher than the biasing force of the biasing member (45) that biases the second on-off valve to the closed side. The system has a configuration in which the gas fuel that flows out from the communication hole and undergoes adiabatic expansion upon opening of the second on-off valve collides with the extensions (35, 38) that extend downstream from the compartment, thereby cooling the extensions . The main body portion extends downstream from the outer periphery of the partition portion and has a peripheral wall portion (35) that forms the second fuel passage, and the peripheral wall portion is the extension portion. The second on-off valve has a guide portion (42) that guides the gas fuel that flows out from the communication hole and undergoes adiabatic expansion radially outward and causes it to collide with the circumferential wall, and also has a cylindrical portion (41) that is slidable against the inner circumferential surface of the main body, In the main body, the diameter of the second fuel passage differs between the uppermost portion and its downstream side, and the passage diameter is expanded in the uppermost portion, thereby forming an annular expansion space (S1) on the radially outer side of the cylindrical portion. The guide portion of the second on-off valve guides the gas fuel that flows out from the communication hole and undergoes adiabatic expansion radially outward, and introduces it into the expanded space. The cylindrical portion has an opening (43) that connects the expanded space with an inner space radially inside it, and is a gas fuel injection valve.
  5. The gas fuel injection valve according to any one of claims 2 to 4 , wherein the expanded space is provided with a biasing member (45) that biases the second on-off valve to the closed side.
  6. A gas fuel injection valve (10) that directly injects gaseous fuel into the combustion chamber of an internal combustion engine, It comprises a cylindrical body (11, 12) having a fuel passage inside and a nozzle (15) at its tip, The main body has a partition (33) that divides the fuel passage into an upstream first fuel passage (P1) and a downstream second fuel passage (P2), and the partition is provided with a communication hole (34) that connects the first fuel passage and the second fuel passage. The main body is provided with a first on-off valve (13) that opens and closes the communication hole from the first fuel passage side, a second on-off valve (14) that opens and closes the communication hole from the second fuel passage side, and a sealing member (27) that seals the area around the opening of the communication hole between the first on-off valve and the compartment. The first on-off valve is driven to open by the drive unit (25), while the second on-off valve opens when the pressure in the communication hole becomes higher than the biasing force of the biasing member (45) that biases the second on-off valve to the closed side. The system has a configuration in which the gas fuel that flows out from the communication hole and undergoes adiabatic expansion upon opening of the second on-off valve collides with the extensions (35, 38) that extend downstream from the compartment, thereby cooling the extensions . A gas fuel injection valve in which the total volume of the communication hole provided in the compartment is the volume of residual gas remaining downstream of the first on-off valve after the first on-off valve has been closed and before the first on-off valve is opened again .

Description

The disclosures in this specification relate to gas fuel injection valves. As a gas fuel injection valve used in direct injection gas engines, for example, the gas metering valve described in Patent Document 1 is known. In this gas metering valve, gas fuel leakage is suppressed by providing an elastomer sealing member on an actuator-driven valve member. At the same time, to suppress damage to the sealing member due to heat and pressure generated during combustion in the gas engine, the sealing position of the valve member is positioned far from the fuel outlet opening. Furthermore, in the gas metering valve, a check valve (passive on-off 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. This suppresses the propagation of flames and combustion pressure in the combustion chamber to the sealing member. This effectively protects the elastomer sealing member. Special Publication No. 2023-513065 Longitudinal cross-sectional view of a fuel injection valve.Perspective view of the second cylindrical section.A close-up vertical cross-sectional view showing the nozzle body and the lower on/off valve.Cross-sectional view of line 4-4 in Figure 3.Perspective view of the lower on/off valve.A longitudinal cross-sectional view showing the fuel injection valve in the open position.A longitudinal cross-sectional view showing an enlarged view of the nozzle body and the lower on/off valve in another example.A longitudinal cross-sectional view showing the configuration of a fuel injection valve in another example. The following describes one embodiment of the gas fuel injection valve according to this disclosure, 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 hydrogen, CNG (Compressed Natural Gas), or LNG (Liquefied Natural Gas) as the gas fuel, and the gas fuel is directly injected into the combustion chamber of the gas engine by the gas fuel injection valve. The gas engine is, for example, an on-board engine. The fuel injection system of this embodiment is a so-called low-pressure direct injection system in which gas fuel compressed to approximately a few MPa is injected into the combustion chamber from the fuel injection valve. The configuration of the fuel injector 10 will be explained using Figure 1. In the following explanation, the axis extending longitudinally along the center of the cross-section of the fuel injector 10 is used as the reference point. The direction in which this axis extends is called the axial direction, the direction radiating from the axis is called the radial direction, and the direction extending circumferentially around the axis is called the circumferential direction. Also, in Figure 1, the right side is the base end (upstream side) of the fuel injector 10, and the left side is the tip end (downstream side). The fuel injector 10 comprises, in general terms, a housing 11, a nozzle body 12 located beyond the housing 11, an upper on-off valve 13 reciprocally mounted within the housing 11, and a lower on-off valve 14 reciprocally mounted within the nozzle body 12. The upper on-off valve 13 is an active upstream on-off valve that opens by electromagnetic drive, while the lower on-off valve 14 is a passive downstream on-off valve that opens due to the pressure difference between the upstream and downstream sides. In the fuel injector 10, the lower on-off valve 14 opens in response to the opening of the upper on-off valve 13, and gaseous fuel is injected from the injection port 15 upon opening of these valves 13 and 14. The housing 11 and nozzle body 12 correspond to the "main body," the upper on-off valve 13 corresponds to the "first on-off valve," and the lower on-off valve 14 corresponds to the "second on-off valve." Although not shown due to its known configuration, the fuel injector 10 is assembled to the gas engine such that its tip (nozzle body 12) is exposed into the combustion chamber, and the fuel injector 10 directly injects gaseous fuel into the combustion chamber. The configuration of each part of the fuel injector 10 will be described in detail below. The housing 11 is formed in a cylindrical shape, and a fixed core 21 is fixed within its hollow portion. The upper on-off valve 13 is housed in a position aligned axially with the fixed core 21, allowing for reciprocating motion. The upper on-off valve 13 consists of a movable core. The fixed core 21 is cylindrical, and a first spring 22, consisting of a compression coil spring, is positioned inside it. The first spring 22 is provided between the spring receiving portion 21a of the fixed core 21 and the axial end face of the upper on-off valve 13. The first spring 22 biases the upper on-off valve 13 toward the tip side of the fuel injection valve 10 (i.e., in the direction that closes the communication hole 34, d