A fuel injector and engine

Abstract

The application provides a fuel injector and an engine. The fuel injector comprises a needle valve pair, a clean fuel needle valve and a first fuel needle valve which are arranged on a needle valve body and are independent of each other, a pilot control valve assembly for controlling the opening and closing of the clean fuel needle valve, and a clean fuel pressure chamber. The clean fuel pressure chamber is in fluid communication with the needle valve pair, so that the clean fuel can be pressurized in the clean fuel pressure chamber and then flow out of the needle valve pair for injection. The needle valve pair is arranged at one end of the fuel injector, the clean fuel pressure chamber is arranged at the other end of the fuel injector, and the pilot control valve assembly is arranged in the middle of the fuel injector.

Description

Technical Field

[0001] This application relates to a fuel injector and an engine. Background Technology

[0002] High-pressure clean fuel direct injection technology, as a core development direction of modern engine technology, has significant advantages in improving efficiency and reducing pollutant emissions. Since using clean fuel as the primary fuel generally requires the use of ignition fuel to assist combustion, and also necessitates the provision of conventional fuel as the primary fuel, injector designs that support dual-fuel injection are needed.

[0003] However, the inventors of this application have discovered that when a dual-fuel injector injects clean fuel, the pressure fluctuation of the clean fuel affects the injection stability and combustion effect. On the other hand, due to the limited space for the arrangement of the dual-fuel injector, and the need to arrange independent clean fuel flow channels and ignition fuel flow channels inside the dual-fuel injector, its internal space is further restricted, and its internal structure is complex, making the compact design of the dual-fuel injector a challenge.

[0004] In view of this, the inventors propose a fuel injector and an engine to solve at least one or a combination of the above technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a fuel injector.

[0006] Another objective of this application is to provide an engine.

[0007] A fuel injector according to a first aspect of this application includes: a needle valve assembly including a needle valve body, and a clean fuel needle valve and a first fuel needle valve disposed on the needle valve body, the clean fuel needle valve and the first fuel needle valve being independent of each other; a pilot control valve assembly for controlling the opening and closing of the clean fuel needle valve; and a clean fuel accumulator chamber; wherein the clean fuel accumulator chamber is fluidly connected to the needle valve assembly, such that clean fuel can first be pressurized inside the clean fuel accumulator chamber and then flow out from the needle valve assembly for injection; and the needle valve assembly is located at one end of the fuel injector, the clean fuel accumulator chamber is located at the other end of the fuel injector, and the pilot control valve assembly is located in the middle of the fuel injector.

[0008] By setting up the clean fuel accumulator chamber, pressure fluctuations during clean fuel injection are effectively reduced, improving injection stability and combustion efficiency. The principle is that, compared to traditional fuels, clean fuels generally have lower calorific value, lower viscosity, and lower density, resulting in a greater injection volume requirement for the fuel injector. This high-flow-rate injection necessitates larger dimensions for the injector's internal flow channels and accumulator volume. Therefore, the clean fuel accumulator chamber is designed to increase the accumulator volume, allowing the clean fuel to flow into the chamber before injection, thus reducing pressure fluctuations through accumulation. Furthermore, the clean fuel accumulator chamber... The injector supporting dual-fuel injection has a complex structure and extremely limited internal space. Furthermore, the pilot control valve assembly needs to act on the needle valve assembly to control the opening and closing of the clean fuel needle valve. Therefore, arranging the pilot control valve assembly in the middle of the injector, compared to an arrangement where the pilot control valve assembly and the needle valve assembly are isolated by the clean fuel accumulator, allows the pilot control valve assembly to be closer to the needle valve assembly, which is more conducive to the compact design of the pilot control valve assembly. It also provides a basis for the integrated design between the structures of the pilot control valve assembly and the needle valve assembly, so as to make better use of space.

[0009] In one or more embodiments of the fuel injector, the clean fuel needle valve includes a first cavity disposed in the needle valve body and a first valve stem adapted to the first cavity; the pilot control valve assembly includes a pilot control valve body; the pilot control valve body is provided with a control cavity; the pilot control valve body and the needle valve body are connected, a guide section is provided between the first cavity and the control cavity, and control oil inside the control cavity provides a force to the first valve stem to cause the clean fuel needle valve to close.

[0010] In one or more embodiments of the fuel injector, the pilot control valve assembly further includes a pilot control drive unit for controlling the control oil pressure inside the control chamber; the pilot control drive unit includes an electromagnet and an armature; when the electromagnet is energized to generate magnetic force, the armature moves under the action of the magnetic force, causing the pilot control valve assembly to open, and the control oil flows out from inside the control chamber to relieve pressure.

[0011] In one or more embodiments of the fuel injector, the first cavity is provided with a clean fuel reservoir; the clean fuel inside the clean fuel reservoir provides a force to the first valve stem that tends to open the clean fuel needle valve.

[0012] In one or more embodiments of the fuel injector, the needle valve assembly further includes a spring; the control chamber is provided with a spring cavity; the spring is located inside the spring cavity and one end is connected to the first valve stem to provide force to the first valve stem.

[0013] In one or more embodiments of the fuel injector, the pilot control valve body is provided with a guide hole; the guide hole is adapted to the armature to guide the movement direction of the armature; the guide hole is provided with a control oil cavity, the control oil cavity and the spring cavity are fluidly connected through an oil outlet orifice; when the pilot control valve assembly is opened, the control oil cavity and the pressure relief cavity are fluidly connected, and control oil flows from the spring cavity through the oil outlet orifice and the control oil cavity to the pressure relief cavity, thereby relieving pressure inside the control cavity.

[0014] In one or more embodiments of the fuel injector, the control oil pressure inside the control chamber is always greater than the clean fuel pressure inside the first chamber.

[0015] In one or more embodiments of the fuel injector, a guide section is provided between the first cavity and the first valve stem; in the guide section, the wall of the first cavity is adapted to the first valve stem to guide the movement direction of the first valve stem; the guide section is located between the control cavity and the clean fuel reservoir; and the guide section is configured such that when the clean fuel needle valve is opened, the control cavity is sealed for clean fuel.

[0016] In one or more embodiments of the fuel injector, the fuel injector is configured with a first state and a second state; in the first state, the electromagnet is energized to generate magnetic force, and the armature moves under the action of the magnetic force, causing the pilot control valve assembly to open, and control oil flows out from the control chamber to relieve pressure, reducing the force that tends to close the clean fuel needle valve until it is overcome by the force that tends to open the clean fuel needle valve, at which point the clean fuel needle valve opens, and clean fuel flows out from the first cavity for injection; in the second state, the electromagnet is de-energized, and the movement of the armature causes the pilot control valve assembly to close, and control oil flows into the control chamber to build up pressure, increasing the force that tends to close the clean fuel needle valve until it overcomes the force that tends to open the clean fuel needle valve, at which point the clean fuel needle valve closes, and the first cavity is sealed from the outside.

[0017] In one or more embodiments of the fuel injector, the outer wall surface of the needle valve body is provided with an arcuate structure.

[0018] In one or more embodiments of the fuel injector, it further includes a clean fuel inlet located at the end of the clean fuel accumulator, the clean fuel inlet being in fluid communication with the clean fuel accumulator.

[0019] An engine according to a second aspect of this application includes the fuel injector described in the above embodiments; the fuel injector injects clean fuel and first fuel through the clean fuel needle valve and the first fuel needle valve, or injects first fuel only through the first fuel needle valve. Attached Figure Description

[0020] The above and other features, properties, and advantages of this application will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features. It should be noted that these drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the scope of protection actually claimed by this application, wherein:

[0021] Figure 1 This is a schematic diagram of the structure of a fuel injector according to an embodiment of this application.

[0022] Figure 2 This is a partial structural schematic diagram of a fuel injector according to an embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the structure of a needle valve assembly according to an embodiment of this application.

[0024] Figure 4 This is a schematic diagram of the structure of a needle valve assembly according to an embodiment of this application.

[0025] Figure label:

[0026] 1. Fuel injector;

[0027] 10. Needle valve assembly; 110. Needle valve body; 111. Arc-shaped structure; 120. Clean fuel needle valve; 1210. First cavity; 1211. Clean fuel reservoir; 122. First valve stem; 123. Guide section; 130. First fuel needle valve; 1310. Second cavity; 1311. First fuel reservoir; 132. Second valve stem; 14. Spring;

[0028] 20. Pilot control valve assembly; 210. Pilot control valve body; 211. Spring cavity; 2120. Guide hole; 213. Control oil cavity; 214. Oil outlet orifice; 215. Oil inlet orifice; 216. Pressure relief chamber; 217. Oil inlet passage; 220. Pilot control drive unit; 221. Electromagnet; 222. Armature; 223. Return spring;

[0029] 30. Clean the fuel accumulator chamber;

[0030] 40. Shell; 41. Clean fuel inlet; 42. Control oil inlet; 43. First fuel inlet. Detailed Implementation

[0031] Various embodiments of this application will now be described in detail, examples of which are shown in the accompanying drawings and described below. Although this application will be described in conjunction with exemplary embodiments, it should be understood that this application is not intended to be limited to those exemplary embodiments. Rather, this application is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of this application as defined by the appended claims.

[0032] This application uses specific terms to describe its embodiments. For example, "an embodiment" and / or "one embodiment" refers to a feature, structure, or characteristic associated with at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" mentioned twice or more in different locations in this application does not necessarily refer to the same embodiment; furthermore, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined. In this application, the terms "first," "second," etc., are only for distinguishing descriptions and should not be construed as indicating or implying positional relationships or order of importance. In the following description, unless otherwise expressly specified or limited, the orientation terms "upper," "lower," "left," "right," "front," "rear," or other directional terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and / or implemented in a specific orientation, and therefore should not be construed as a limitation of this application. In the following description, unless otherwise expressly specified or limited, the terms "connection," "linked," "connected," etc., should be interpreted broadly; for example, they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0033] It is understood that the fuel injector and engine provided in this application are particularly suitable for marine engines, and can also be applied to other applications requiring dual-fuel injection, such as vehicles, railway trains, power generation equipment, etc., without limitation.

[0034] See Figures 1 to 4A fuel injector 1 is shown, comprising: a needle valve assembly 10, including a needle valve body 110, and a clean fuel needle valve 120 and a first fuel needle valve 130 disposed on the needle valve body 110, the clean fuel needle valve 120 and the first fuel needle valve 130 being independent of each other; a pilot control valve assembly 20 for controlling the opening and closing of the clean fuel needle valve 120; and a clean fuel accumulator chamber 30; wherein the clean fuel accumulator chamber 30 is fluidly connected to the needle valve assembly 10, so that clean fuel can be pressurized inside the clean fuel accumulator chamber 30 and then flow out from the needle valve assembly 10 for injection; and the needle valve assembly 10 is located at one end of the fuel injector 1, the clean fuel accumulator chamber 30 is located at the other end of the fuel injector 1, and the pilot control valve assembly 20 is located in the middle of the fuel injector 1, that is, the pilot control valve assembly 20 is generally arranged between the needle valve assembly 10 and the clean fuel accumulator chamber 30.

[0035] Specifically, the clean fuel needle valve 120 is used to inject clean fuel (e.g., methanol fuel), and the first fuel needle valve 130 is used to inject a first fuel; the first fuel is a conventional fuel different from the clean fuel, such as diesel, but not limited thereto; optionally, the clean fuel needle valve 120 and the first fuel needle valve 130 are respectively connected to different flow channels and pressurize independently to achieve independent operation; optionally, the fuel injector 1 is configured to have a first mode and a second mode; in the first mode, the fuel injector 1 can inject clean fuel through the clean fuel needle valve 120 and the first fuel respectively. The needle valve 130 simultaneously injects clean fuel and first fuel. In this mode, the first fuel can be used as the ignition fuel for the clean fuel. In the second mode, the fuel injector 1 can inject the first fuel only through the first fuel needle valve 130. In this mode, the first fuel can be used as the main fuel to provide engine power. Optionally, the clean fuel accumulator chamber 30 is provided by the housing 40 of the fuel injector 1. The housing 40 can also be configured to have a clean fuel inlet 41, a control oil inlet 42, and a first fuel inlet 43, for external clean fuel, control oil, and first fuel to flow into the fuel injector 1, respectively.

[0036] By employing the fuel injector 1 described above and setting the clean fuel accumulator chamber 30, pressure fluctuations of the clean fuel during injection are effectively reduced, thereby improving the injection stability and combustion performance. The principle is that, compared to traditional fuels, clean fuels generally have lower calorific value, lower viscosity, and lower density, resulting in a greater injection volume requirement for the fuel injector 1 when injecting clean fuel. This, in turn, places greater demands on the size of the flow channels and accumulator volume within the injector. Therefore, the clean fuel accumulator chamber 30 is set up to increase the accumulator volume of the clean fuel, allowing the clean fuel to flow into the chamber before injection. This accumulator suppresses pressure fluctuations, thus stabilizing the injection. On the other hand… As mentioned above, due to the complex structure of the injector supporting dual-fuel injection and its extremely limited internal space, and because the pilot control valve assembly 20 needs to act on the needle valve assembly 10 to control the opening and closing of the clean fuel needle valve 120, the pilot control valve assembly 20 is located in the middle of the injector. Compared to the arrangement in which the pilot control valve assembly 20 and the needle valve assembly 10 are isolated by the clean fuel accumulator 30, this arrangement allows the pilot control valve assembly 20 to be closer to the needle valve assembly 10, which is more conducive to the compact design of the pilot control valve assembly 20. It also provides a basis for the structural integration design between the pilot control valve assembly 20 and the needle valve assembly 10, so as to make fuller use of space.

[0037] like Figures 2 to 4 As shown, in one or more embodiments of the fuel injector 1, the clean fuel needle valve 120 includes a first cavity 1210 disposed in the needle valve body 110, and a first valve stem 122 adapted to the first cavity 1210; the pilot control valve assembly 20 includes a pilot control valve body 210; the pilot control valve body 210 is provided with a control cavity, for example, the control cavity includes a spring cavity 211; the pilot control valve body 210 and the needle valve body 110 are connected, the first cavity 1210 and the control cavity are in communication, and the control oil inside the control cavity provides a force to the first valve stem 122 that causes the clean fuel needle valve 120 to tend to close.

[0038] By connecting the pilot control valve body 210 and the needle valve body 110, and providing a guide section 123 between the first cavity 1210 and the control cavity, the first valve stem 122 can be housed within the accommodating space formed by the first cavity 1210 and the control cavity, thus achieving structural integration of the needle valve assembly 10 and the pilot control valve assembly 20, which facilitates the compactness of the fuel injector 1. Furthermore, by providing the control cavity in the pilot control valve body 210, compared to a separate configuration of the control cavity and the pilot control valve assembly 20, there is no need to provide an additional oil flow channel for controlling the flow of oil between the control cavity and the pilot control valve assembly 20. This helps to reduce the oil delivery distance and the volume of the control cavity, thereby reducing the control oil flow rate inside the control cavity to ensure rapid pressure relief, and effectively shortening the response time for controlling clean fuel injection.

[0039] Optionally, the fuel injector 1 is configured to use a control oil that is different from the clean fuel, in order to avoid the clean fuel from vaporizing under a large pressure gradient, which would affect the reliability and injection stability of the pilot control valve assembly 20; the first cavity 1210 is provided with a nozzle; the first valve stem 122 is movably disposed inside the first cavity 1210 and is provided with a sealing structure that can seal with the nozzle, so that the movement of the first valve stem 122 realizes the opening and closing of the clean fuel needle valve 120; the first valve stem 122 may also be provided with a shoulder, so that it can abut against the end face of the pilot control valve body 210 to limit the movable stroke of the first valve stem 122; the oil inlet channel 217 is fluidly connected to the spring cavity 211 through the oil inlet metering hole 215, so that the control oil can flow from the oil inlet channel 217 through the oil inlet metering hole 215 to the spring cavity 211 to build pressure inside the control cavity.

[0040] like Figure 2 As shown, in one or more embodiments of the fuel injector 1, the pilot control valve assembly 20 further includes a pilot control drive unit 220 for controlling the control oil pressure inside the control chamber.

[0041] Specifically, the pilot control drive unit 220 may include an electromagnet 221 and an armature 222. The electromagnet 221 is disposed inside the injector housing 40 and fixedly connected to the pilot control valve body 210. The pilot control valve body 210 provides a accommodating space for the armature 222, allowing the armature 222 to move under the drive of the electromagnet 221. When the electromagnet 221 is energized and generates magnetic force, the armature 222 moves under the action of the magnetic force, causing the pilot control valve assembly 20 to open, and control oil flows from the control chamber. The oil flows out to relieve pressure; the armature 222 can also be connected to the return spring 223, for example, the return spring is located between the electromagnet 221 and the armature 222; when the electromagnet 221 is de-energized, the armature 222 is reset under the elastic force of the return spring 223, so that the pilot control valve assembly 20 is closed, and the control oil is sealed inside the control chamber to build up pressure; the pilot control drive unit 220 controls the control oil pressure inside the control chamber by controlling the opening and closing of the pilot control valve assembly 20.

[0042] like Figure 2 As shown, in one or more embodiments of the fuel injector 1, the needle valve assembly 10 further includes a spring 14; the control cavity is provided with the spring cavity 211; the spring 14 is located inside the spring cavity 211, and one end is connected to the first valve stem 122 to provide force to the first valve stem 122.

[0043] Optionally, one end of the first valve stem 122 extends into the spring cavity 211 and has a protrusion; one end of the spring 14 is connected to the end face of the spring cavity 211, and the other end is fitted onto the protrusion to stabilize the spring 14; the control oil inside the spring cavity 211 and the spring 14 can jointly provide a force to the end of the first valve stem 122, causing the first valve stem 122 to be pressed in a direction tending to close the clean fuel needle valve, for example... Figure 2 The image shows something being pressed downwards.

[0044] like Figure 3 , Figure 4 As shown, in one or more embodiments of the fuel injector 1, the first cavity 1210 is provided with a clean fuel holding tank 1211; the clean fuel inside the clean fuel holding tank 1211 acts on the first valve stem 122 to provide a force that tends to open the clean fuel needle valve 120.

[0045] Specifically, the clean fuel holding tank 1211 can be located in the middle of the first cavity 1210, and the first valve stem 122 can have a change in cross-sectional area at the position corresponding to the first cavity 1210, so as to generate a force under the action of clean fuel pressure that tends to open the clean fuel needle valve 120, for example... Figure 3 The design causes the first valve stem 122 to be pressed upwards. Optionally, the clean fuel reservoir 1211 is fluidly connected to the clean fuel accumulator 30, and a clean fuel flow channel is provided between the clean fuel reservoir 1211 and the clean fuel nozzle, allowing the clean fuel to flow to the nozzle for injection. Optionally, the clean fuel flows into the clean fuel accumulator 30 and the clean fuel reservoir 1211 respectively after passing through the clean fuel inlet 41. By providing the clean fuel reservoir 1211, a simplified and reliable clean fuel injection control structure is provided, which is beneficial for the compactness of the fuel injector 1.

[0046] like Figure 3 As shown, it can be understood that the first fuel needle valve 130 can be configured with a structure similar to that of the clean fuel needle valve 120; for example, it includes a second cavity 1310, a second valve stem 132, a first fuel holding tank 1311, etc., which will not be described in detail here.

[0047] like Figure 2As shown, in one or more embodiments of the fuel injector 1, the pilot control valve body 210 is provided with a guide hole 2120; the guide hole 2120 is adapted to the armature 222 to guide the movement direction of the armature 222; the guide hole 2120 is provided with a control oil cavity 213, and an oil outlet hole 214 is provided between the control oil cavity 213 and the spring cavity 211 to achieve fluid communication; the spring cavity 211 and the control oil cavity 213 are fluidly connected, together forming The control chamber is formed; by setting the guide hole 2120 and the spring cavity 211 to be located in the pilot control valve body 210, the oil outlet orifice 214 can be configured as a shorter flow channel, which is beneficial to reduce the oil delivery distance and improve the control response speed; the control oil cavity 213 is also connected to the pressure relief cavity 216, and the fluid flow between the control oil cavity 213 and the pressure relief cavity 216 is realized by the opening and closing of the pilot control valve assembly 20; for example, the armature 222 and the valve port can be sealed together, through The armature 222 is controlled to move, opening or closing the valve port between the control oil chamber 213 and the pressure relief chamber 216. When the pilot control valve assembly 20 is open, the control oil chamber 213 and the pressure relief chamber 216 are fluidly connected, and control oil flows out from the spring chamber 211 through the oil outlet orifice 214, the control oil chamber 213, and out of the pressure relief chamber 216, thereby relieving pressure inside the control chamber. Specifically, it can also be configured to consist of the pilot control valve body 210 and the needle valve body 11. The end faces of 0 together form the pressure relief chamber 213, which further integrates the pilot control valve assembly 20 and the needle valve assembly 10, and makes them easier to process and manufacture. Compared with the traditional pilot valve assembly with independent guide structures and orifice plates, by setting the control oil chamber 213 in the guide hole 2120 and opening the oil outlet orifice 214, the structure and function of the traditional guide structure and orifice plate are integrated into one, which simplifies the structure, facilitates the compact design of the fuel injector 1, and reduces the cost.

[0048] In one or more embodiments of the fuel injector 1, the control oil pressure inside the control chamber is always greater than the clean fuel pressure inside the first cavity 1210, where the control oil pressure and clean fuel pressure refer to the pressures of the control oil and clean fuel, respectively.

[0049] It can be understood that, since the first valve stem 122 is movably housed inside the first cavity 1210, and there is a certain gap between it and the wall of the first cavity 1210, the space formed by the first cavity 1210 and the control cavity is connected. Therefore, by setting the control oil pressure inside the control cavity to always be greater than the clean fuel pressure inside the first cavity 1210, the clean fuel is effectively prevented from leaking into the control cavity through the gap, thereby effectively preventing the clean fuel from corroding components (such as electromagnet 221) and contaminating the control oil return.

[0050] like Figure 3 , Figure 4 As shown, in one or more embodiments of the fuel injector 1, a guide section 123 is provided between the first cavity 1210 and the first valve stem 122; in the guide section 123, the wall of the first cavity 1210 and the first valve stem 122 are adapted to guide the movement direction of the first valve stem 122; the guide section 123 is located between the control cavity and the clean fuel reservoir 1211; the guide section 123 is configured such that when the clean fuel needle valve 120 is opened, the control cavity is sealed to clean fuel; specifically, this can be achieved by appropriately configuring at least one of the length of the guide section 123 and the gap between the wall of the first cavity 1210 and the first valve stem 122 in the guide section 123. This design helps to ensure that clean fuel does not leak into the control cavity, improving the reliability of the fuel injector 1, etc.

[0051] In one or more embodiments of the fuel injector 1, the fuel injector 1 is configured with a first state and a second state. In the first state, the electromagnet 221 is energized to generate magnetic force, and the armature 222 moves under the action of the magnetic force, causing the pilot control valve assembly 20 to open, and control oil flows out from the control chamber to relieve pressure. For example, the armature 222 moves under the action of the magnetic force (moving upward as shown in the figure), so that the control oil cavity 213 and the pressure relief cavity 216 are fluidly connected. The control oil flows out from the spring cavity 211, then through the oil outlet orifice 214, flows to the control oil cavity 213, then flows out through the pressure relief cavity 216, and returns, etc., to relieve pressure in the control chamber. When the clean fuel in the clean fuel reservoir 1211 exerts a force on the first valve stem 122, it overcomes the force exerted by the control oil in the control chamber and the force exerted by the spring 14 on the first valve stem 122. In the first state, the first valve stem 122 moves (as shown in the figure, upward movement) to open the clean fuel needle valve 120, and clean fuel flows from the clean fuel reservoir 1211 in the clean fuel chamber to the nozzle for injection. In the second state, the electromagnet 221 is de-energized, and the armature 222 moves, for example, driven by the return spring 223, causing the pilot control valve assembly 20 to close, sealing the control oil chamber 213 and the pressure relief chamber 216. Control oil flows from the oil inlet channel 216 to the inside of the spring chamber 211 to build pressure. The control oil inside the control chamber and the spring 14 provide a force on the first valve stem 122 to overcome the force provided by the clean fuel in the clean fuel reservoir 1211 on the first valve stem 122, causing the clean fuel needle valve 120 to close, the first chamber 1210 to be sealed from the outside, and the clean fuel injection stops.

[0052] like Figure 3 As shown, in one or more embodiments of the fuel injector 1, the outer wall surface of the needle valve body 110 is provided with an arcuate structure 111; specifically, the arcuate structure 111 can be configured to surround the outer wall surface of the needle valve body 110 in a complete circumference. The arcuate structure 111 can be used to form a sealing fit with the support structure on the outer periphery of the fuel injector 1, so as to prevent fuel or the like inside the cylinder from leaking to the outside; compared with the fuel injector 1 without this arcuate structure 111 (such as... Figure 4 As shown in the figure, no separate sealing gasket is required, making the overall structure of the engine simple and compact.

[0053] In one or more embodiments of the fuel injector 1, it further includes a clean fuel inlet 41 located at the top of the clean fuel accumulator 30, the clean fuel inlet 41 being in fluid communication with the clean fuel accumulator 30. This design facilitates the structural arrangement of the cylinder head and the fuel injector 1, as well as the flow path arrangement for clean fuel to enter the fuel injector 1, resulting in a more compact overall engine structure.

[0054] This application also provides a fuel injection system, which includes the fuel injector 1 described in the above embodiments; the fuel injector 1 injects clean fuel and first fuel through the clean fuel needle valve 120 and the first fuel needle valve 130, or injects the first fuel only through the first fuel needle valve 130.

[0055] This application also provides an engine, such as a marine engine, which includes the fuel injector 1 described in the above embodiments; the fuel injector 1 injects clean fuel and first fuel through the clean fuel needle valve 120 and the first fuel needle valve 130, or injects the first fuel only through the first fuel needle valve 130; optionally, the first fuel is different from the clean fuel, and when the clean fuel and the first fuel are injected simultaneously, the first fuel serves as the ignition fuel for the clean fuel.

[0056] In summary, the beneficial effects of using the fuel injector and engine described in the above embodiments include, but are not limited to, at least one of the following:

[0057] By setting up the clean fuel accumulator chamber, pressure fluctuations during clean fuel injection are effectively reduced, improving injection stability and combustion performance. The principle is that, compared to traditional fuels, clean fuels generally have lower calorific value, lower viscosity, and lower density, resulting in a greater injection volume requirement for fuel injectors. This high-flow-rate injection necessitates larger dimensions for the injector's internal flow channels and accumulator volume. Therefore, the clean fuel accumulator chamber increases the accumulator volume, allowing the clean fuel to flow into the chamber before injection, suppressing pressure fluctuations and stabilizing injection. In this regard, as mentioned above, due to the complex structure of the injector supporting dual-fuel injection and its extremely limited internal space, and because the pilot control valve assembly needs to act on the needle valve assembly to control the opening and closing of the clean fuel needle valve, arranging the pilot control valve assembly in the middle of the injector, compared to an arrangement where the pilot control valve assembly and the needle valve assembly are isolated by the clean fuel accumulator, allows the pilot control valve assembly to be closer to the needle valve assembly, which is more conducive to the compact design of the pilot control valve assembly. It also provides a basis for the structural integration design between the pilot control valve assembly and the needle valve assembly, so as to make fuller use of space.

[0058] While this application discloses preferred embodiments as described above, it is not intended to limit the scope of this application. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this application. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application, without departing from the content of the technical solution of this application, fall within the protection scope defined by the claims of this application.

Claims

1. A fuel injector (1), characterized in that, include: The needle valve assembly (10) includes a needle valve body (110), and a clean fuel needle valve (120) and a first fuel needle valve (130) disposed on the needle valve body (110), wherein the clean fuel needle valve (120) and the first fuel needle valve (130) are independent of each other; A pilot control valve assembly (20) is used to control the opening and closing of the clean fuel needle valve (120); Clean fuel accumulator chamber (30); wherein, The clean fuel accumulator (30) is fluidly connected to the needle valve assembly (10), so that the clean fuel can be pressurized inside the clean fuel accumulator (30) and then flow out from the needle valve assembly (10) for injection; and the needle valve assembly (10) is located at one end of the fuel injector (1), the clean fuel accumulator (30) is located at the other end of the fuel injector (1), and the pilot control valve assembly (20) is located in the middle of the fuel injector (1); The pilot control valve assembly (20) includes a pilot control valve body (210) having a control chamber; the pilot control valve assembly (20) also includes a pilot control drive unit (220) for controlling the control oil pressure inside the control chamber; the pilot control drive unit (220) includes an armature (222). The pilot control valve body (210) is provided with a guide hole (2120); the guide hole (2120) is adapted to the armature (222) to guide the movement direction of the armature (222); the guide hole (2120) is provided with a control oil cavity (213), the control oil cavity (213) and the spring cavity (211) are fluidly connected through an oil outlet orifice (214); when the pilot control valve assembly (20) is opened, the control oil cavity (213) and the pressure relief cavity (216) are fluidly connected, and control oil flows from the spring cavity (211) through the oil outlet orifice (214) and the control oil cavity (213) to the pressure relief cavity (216), thereby relieving pressure inside the control cavity.

2. The fuel injector (1) according to claim 1, characterized in that, The clean fuel needle valve (120) includes a first cavity (1210) disposed in the needle valve body (110) and a first valve stem (122) adapted to the first cavity (1210); the pilot control valve body (210) is connected to the needle valve body (110), a guide section (123) is provided between the first cavity (1210) and the control cavity, and the control oil inside the control cavity provides a force to the first valve stem (122) to make the clean fuel needle valve (120) tend to close.

3. The fuel injector (1) according to claim 2, characterized in that, The pilot control drive unit (220) includes an electromagnet (221); when the electromagnet (221) is energized to generate magnetic force, the armature (222) moves under the action of magnetic force, causing the pilot control valve assembly (20) to open, and control oil flows out from the inside of the control chamber to relieve pressure.

4. The fuel injector (1) according to claim 2, characterized in that, The first cavity (1210) is provided with a clean fuel holding tank (1211); the clean fuel inside the clean fuel holding tank (1211) provides a force to the first valve stem (122) that tends to open the clean fuel needle valve (120).

5. The fuel injector (1) according to claim 2, characterized in that, The needle valve assembly (10) also includes a spring (14); the control cavity is provided with a spring cavity (211); the spring (14) is located inside the spring cavity (211), and one end is connected to the first valve stem (122) to provide force to the first valve stem (122).

6. The fuel injector (1) according to claim 2, characterized in that, The control oil pressure inside the control chamber is always greater than the clean fuel pressure inside the first cavity (1210).

7. The fuel injector (1) according to claim 4, characterized in that, A guide section (123) is provided between the first cavity (1210) and the first valve stem (122); in the guide section (123), the wall of the first cavity (1210) is adapted to the first valve stem (122) to guide the movement direction of the first valve stem (122); the guide section (123) is located between the control cavity and the clean fuel container (1211); and the guide section (123) is configured such that when the clean fuel needle valve (120) is opened, the control cavity is sealed for clean fuel.

8. The fuel injector (1) according to claim 3, characterized in that, The fuel injector (1) is configured with a first state and a second state; In the first state, the electromagnet (221) is energized to generate magnetic force, and the armature (222) moves under the action of magnetic force, causing the pilot control valve assembly (20) to open. Control oil flows out from the control chamber to relieve pressure, reducing the force that tends to close the clean fuel needle valve (120) until it is overcome by the force that tends to open the clean fuel needle valve (120). Then the clean fuel needle valve (120) opens, and clean fuel flows out from the first cavity (1210) for injection. In the second state, the electromagnet (221) is de-energized, and the armature (222) moves to close the pilot control valve assembly (20). Control oil flows into the control chamber to build pressure, increasing the force that tends to close the clean fuel needle valve (120) until it overcomes the force that tends to open the clean fuel needle valve (120). At this point, the clean fuel needle valve (120) closes, and the first cavity (1210) is sealed off from the outside.

9. The fuel injector (1) according to claim 1, characterized in that, The outer wall of the needle valve body (110) is provided with an arc-shaped structure (111).

10. The fuel injector (1) according to claim 1, characterized in that, It also includes a clean fuel inlet (41) located at the end of the clean fuel accumulator (30), the clean fuel inlet (41) being in fluid communication with the clean fuel accumulator (30).

11. An engine, characterized in that, Includes a fuel injector (1) as described in any one of claims 1 to 10; the fuel injector (1) injects clean fuel and first fuel through the clean fuel needle valve (120) and the first fuel needle valve (130), or injects first fuel only through the first fuel needle valve (130).

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