Fuel injector and engine

Abstract

The invention provides a fuel injector and an engine. Wherein the fuel injector comprises a needle valve matching part, the needle valve matching part comprises a needle valve body, a clean fuel needle valve and a first fuel needle valve, the clean fuel needle valve and the first fuel needle valve are arranged on the needle valve body, and the clean fuel needle valve and the first fuel needle valve are mutually independent; the pilot control valve assembly is used for controlling opening and closing of the clean fuel needle valve; a clean fuel pressure storage cavity; the clean fuel pressure storage cavity is communicated with the needle valve matching part in a fluid mode, so that clean fuel can be subjected to pressure storage in the clean fuel pressure storage cavity firstly, and then flows out of the needle valve matching part to be injected. Moreover, the needle valve matching part is located at the end of one side of the fuel injector, the clean fuel pressure storage cavity is located at the end of the other side of the fuel injector, and the pilot control valve assembly is located in the middle of the fuel injector.

Description

Technical Field

[0001] The present application relates to a fuel injector and an engine. Background Art

[0002] As the core development direction of modern engine technology, the high-pressure clean fuel in-cylinder direct injection technology has significant advantages in improving efficiency and reducing pollutant emissions. Since using clean fuel as the main fuel generally requires the use of pilot fuel for auxiliary combustion and the need to provide a working mode with traditional fuel as the main fuel, it is necessary to carry out the design of an injector that supports dual-fuel injection.

[0003] However, the inventors of the present application have found that when the 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 layout space of the dual-fuel injector and the need to arrange independent clean fuel flow channels and pilot fuel flow channels inside the dual-fuel injector, the internal space is further limited and the internal structure is complex, making the compact design of the dual-fuel injector a difficult problem.

[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 object of the present application is to provide a fuel injector.

[0006] Another object of the present application is to provide an engine.

[0007] A fuel injector according to the first aspect of the present application includes: a needle valve pair, 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; a clean fuel accumulator chamber; wherein, the clean fuel accumulator chamber is fluidly connected to the needle valve pair, so that clean fuel can be pressurized inside the clean fuel accumulator chamber first and then flow out from the needle valve pair for injection; and, the needle valve pair 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 the clean fuel accumulator chamber, it is possible to effectively reduce the pressure fluctuation of the clean fuel during injection, improve the injection stability of the clean fuel, and improve the combustion effect. The principle is that, compared with traditional fuels, clean fuels generally have characteristics such as low calorific value, low viscosity, and low density, which makes the fuel injector face a greater injection volume demand when injecting clean fuel. Furthermore, a large-flow injection requires larger sizes for the internal flow channels and accumulator volume of the injector. Therefore, the clean fuel accumulator chamber is set to increase the accumulator volume, so that the clean fuel flows into the interior of the clean fuel accumulator chamber before injection, and the pressure fluctuation is reduced through pressure accumulation. On the other hand, since the injector structure supporting dual-fuel injection is complex and the internal space is extremely limited, and the pilot control valve assembly needs to act on the needle valve pair to control the opening and closing of the clean fuel needle valve, the pilot control valve assembly is arranged in the middle of the injector. Compared with the arrangement scheme in which the pilot control valve assembly and the needle valve pair are isolated by the clean fuel accumulator chamber, the pilot control valve assembly is closer to the needle valve pair, which is more conducive to the compact design of the pilot control valve assembly and can also provide a basis for the integrated design between the structures of the pilot control valve assembly and the needle valve pair to make more full use of the space, etc.

[0009] In one or more embodiments of the fuel injector, the clean fuel needle valve includes a first cavity provided 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 is connected to the needle valve body, and a guiding section is provided between the first cavity and the control cavity, and the control oil inside the control cavity provides a force for the first valve stem to tend to close the clean fuel needle valve.

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

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

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

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

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

[0015] In one or more embodiments of the fuel injector, a guiding section is provided between the first cavity and the first valve stem; in the guiding section, the wall surface of the first cavity fits the first valve stem to guide the movement direction of the first valve stem; the guiding section is located between the control cavity and the clean fuel storage tank; and the guiding section is configured such that when the clean fuel needle valve is opened, the control cavity is sealed for the 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 a magnetic force, and the armature moves under the action of the magnetic force, so that the pilot control valve assembly is opened, and the control oil flows out from the inside of the control cavity to relieve pressure, so that the force tending to close the clean fuel needle valve decreases until it is overcome by the force tending to open the clean fuel needle valve, and then the clean fuel needle valve is opened, and the clean fuel flows out from the first cavity for injection; in the second state, the electromagnet is de-energized, and the armature moves to close the pilot control valve assembly, and the control oil flows into the inside of the control cavity to build pressure, so that the force tending to close the clean fuel needle valve increases until it overcomes the force tending to open the clean fuel needle valve, and then the clean fuel needle valve is closed, and the first cavity is closed to the outside.

[0017] In one or more embodiments of the fuel injector, the outer side wall surface of the needle valve body is provided with an arc surface 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 cavity, and the clean fuel inlet is fluidly connected to the clean fuel accumulator cavity.

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

[0020] The above and other features, properties, and advantages of the present application will become more apparent from the following description in conjunction with the drawings and embodiments, in which the same reference numerals always represent the same features. It should be noted that these drawings are only examples and are not drawn under the condition of equal scale, and should not be used as a limitation on the actual scope of protection required by the present application, where:

[0021] Figure 1 It is a schematic structural diagram of a fuel injector according to an embodiment of the present application.

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

[0023] Figure 3 It is a schematic structural diagram of a needle valve pair according to an embodiment of the present application.

[0024] Figure 4 It is a schematic structural diagram of a needle valve pair according to an embodiment of the present application.

[0025] Reference Numerals:

[0026] 1. Fuel injector;

[0027] 10. Needle valve pair; 110. Needle valve body; 111. Arc surface structure; 120. Clean fuel needle valve; 1210. First cavity; 1211. Clean fuel storage tank; 122. First valve stem; 123. Guide section; 130. First fuel needle valve; 1310. Second cavity; 1311. First fuel storage tank; 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 discharge hole; 215. Oil inlet hole; 216. Pressure relief cavity; 217. Oil inlet channel; 220. Pilot control drive part; 221. Electromagnet; 222. Armature; 223. Return spring;

[0029] 30. Clean fuel accumulator cavity;

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

[0031] The various embodiments of the present application will now be described in detail. Examples of these embodiments are shown in the accompanying drawings and are described as follows. Although the present application will be described in conjunction with exemplary embodiments, it should be appreciated that the present application is not intended to be limited to those exemplary embodiments. On the contrary, the present application is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the present application as defined by the appended claims.

[0032] The present application uses specific terms to describe the embodiments of the present application. For example, "an embodiment" and / or "one embodiment" mean a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" mentioned twice or more at different positions in the present application does not necessarily refer to the same embodiment; in addition, certain features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined. In the present application, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying a positional relationship or an importance ranking, etc. In the following description, unless otherwise clearly specified or limited, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", or other orientation terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and / or implemented in a specific orientation, and therefore cannot be understood as a limitation of the present application. In the following description, unless otherwise clearly specified or limited, terms such as "connected", "coupled", "communicated", etc. should be understood in a broad sense; for example: it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0033] It can be understood that the fuel injector and engine provided by the present application are particularly applicable to marine engines, and can also be applied to other applicable occasions that require dual-fuel injection, such as vehicles, railway trains, power generation equipment, etc., without being limited thereto.

[0034] See Figures 1 to 4A fuel injector 1 as shown includes: a needle valve pair 10, comprising a needle valve body 110, and a clean fuel needle valve 120 and a first fuel needle valve 130 disposed in 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; a clean fuel accumulator chamber 30; wherein, the clean fuel accumulator chamber 30 is in fluid communication with the needle valve pair 10, such that clean fuel can be pressurized inside the clean fuel accumulator chamber 30 and then flow out from the needle valve pair 10 for injection; and, the needle valve pair 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 approximately arranged between the needle valve pair 10 and the clean fuel accumulator chamber 30.

[0035] Specifically, the clean fuel needle valve 120 is used for injecting clean fuel (such as methanol fuel), and the first fuel needle valve 130 is used for injecting first fuel; the first fuel is a conventional fuel different from the clean fuel, such as diesel, etc., 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 independently build pressure 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 simultaneously inject clean fuel and first fuel through the clean fuel needle valve 120 and the first fuel needle valve 130 respectively, and 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 only inject the first fuel through the first fuel needle valve 130, and in this mode, the first fuel can be used as the main fuel for providing 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, which are respectively used for clean fuel, control oil, and first fuel from the outside to flow into the fuel injector 1.

[0036] By adopting the fuel injector 1 described above, by providing the clean fuel accumulator chamber 30, the pressure fluctuation of the clean fuel during injection is effectively reduced, the injection stability of the clean fuel is improved, and the combustion effect is improved. The principle is that, compared with traditional fuels, clean fuels generally have characteristics such as low calorific value, low viscosity, and low density, which makes the fuel injector 1 face a greater injection volume demand when injecting clean fuel. Furthermore, a large-flow injection requires larger sizes for the flow channels and accumulator volumes inside the injector. Therefore, the clean fuel accumulator chamber 30 is provided to increase the accumulator volume of the clean fuel, so that the clean fuel first flows into the inside of the clean fuel accumulator chamber 30 before injection, and the pressure fluctuation is suppressed by accumulator pressure to make the injection stable. On the other hand, as described above, since the injector structure supporting dual-fuel injection is complex and its internal space is extremely limited, and the pilot control valve assembly 20 needs to act on the needle valve pair 10 to control the opening and closing of the clean fuel needle valve 120, the pilot control valve assembly 20 is arranged in the middle of the injector. Compared with the arrangement scheme in which the pilot control valve assembly 20 and the needle valve pair 10 are separated by the clean fuel accumulator chamber 30, the pilot control valve assembly 20 is closer to the needle valve pair 10, which is more conducive to the compact design of the pilot control valve assembly 20, and can also provide a basis for the integrated structure design between the pilot control valve assembly 20 and the needle valve pair 10 to make more full use of the space, etc.

[0037] As Figures 2 to 4 shown, in one or more embodiments of the fuel injector 1, the clean fuel needle valve 120 includes a first cavity 1210 provided 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 is connected to the needle valve body 110, the first cavity 1210 communicates with the control cavity, and the control oil inside the control cavity provides a force for the first valve stem 122 to make the clean fuel needle valve 120 tend to close.

[0038] By setting the connection between the pilot control valve body 210 and the needle valve body 110, and providing a guiding section 123 between the first cavity 1210 and the control cavity, the first valve stem 122 can be accommodated inside the accommodation space formed by the first cavity 1210 and the control cavity, realizing the structural integration of the needle valve pair 10 and the pilot control valve assembly 20, which is beneficial to the compactness of the fuel injector 1. Moreover, by arranging the control cavity in the pilot control valve body 210, compared with the solution where the control cavity and the pilot control valve assembly 20 are separately formed, there is no need to additionally arrange an oil delivery channel for controlling the flow of oil between the control cavity and the pilot control valve assembly 20, which is beneficial to reducing the oil delivery distance of the control oil and the volume of the control cavity, and further reducing the control oil flow inside the control cavity to ensure rapid pressure relief, etc., and can effectively shorten the response time for controlling the injection of clean fuel.

[0039] Optionally, the fuel injector 1 is configured to use the control oil as a fluid different from the clean fuel to avoid the gasification of the clean fuel under a large pressure gradient, which affects 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 arranged inside the first cavity 1210 and is configured with a sealing structure that can cooperate with the nozzle in a sealed manner, so that the opening and closing of the clean fuel needle valve 120 are realized through the movement of the first valve stem 122. The first valve stem 122 can 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 orifice 215, so that the control oil can flow from the oil inlet channel 217 through the oil inlet orifice 215 to the spring cavity 211 to build pressure inside the control cavity.

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

[0041] Specifically, the pilot control driving part 220 may include an electromagnet 221 and an armature 222; the electromagnet 221 is disposed inside the injector housing 40 and is fixedly connected to the pilot control valve body 210, and the pilot control valve body 210 provides an accommodation space for the armature 222 such that the armature 222 can move under the drive of the electromagnet 221; when the electromagnet 221 is energized to generate a magnetic force, the armature 222 moves under the action of the magnetic force, causing the pilot control valve assembly 20 to open, and the control oil flows out from inside the control chamber to relieve pressure; the armature 222 may also be connected to a return spring 223, for example, the return spring is disposed between the electromagnet 221 and the armature 222; when the electromagnet 221 is de-energized, the armature 222 resets under the elastic force of the return spring 223, causing the pilot control valve assembly 20 to close, and the control oil is enclosed inside the control chamber to build pressure; the pilot control driving part 220 controls the opening and closing of the pilot control valve assembly 20 to achieve control of the pressure of the control oil inside the control chamber.

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

[0043] Optionally, one end of the first valve stem 122 extends into the spring accommodation cavity 211 and is provided with a convex portion; one end of the spring 14 is connected to the end face of the spring accommodation cavity 211, and one end is sleeved on the convex portion to stabilize the spring 14; the control oil inside the spring accommodation 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 shown as being pressed downward.

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

[0045] Specifically, the clean fuel storage tank 1211 may be disposed in the middle of the first cavity 1210. The first valve stem 122 may have a change in cross-sectional area at a position corresponding to the first cavity 1210 to generate a force that tends to open the clean fuel needle valve 120 under the action of the clean fuel pressure. For example Figure 3 as shown in Figure 3 , the first valve stem 122 is pressed upwardly; optionally, the clean fuel storage tank 1211 is fluidly connected to the clean fuel pressure accumulator chamber 30, and a flow path for the clean fuel is provided between the clean fuel storage tank 1211 and the clean fuel nozzle so that the clean fuel can flow to the nozzle for injection; optionally, the clean fuel flows into the clean fuel pressure accumulator chamber 30 and the clean fuel storage tank 1211 respectively after passing through the clean fuel inlet 41. By providing the clean fuel storage tank 1211, a compact and reliable clean fuel injection control structure is provided, which is beneficial to the compactness of the fuel injector 1.

[0046] As Figure 3 shown in Figure 3 , it can be understood that the first fuel needle valve 130 may 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 storage tank 1311, etc., which will not be elaborated here.

[0047] As Figure 2As shown, in one or more embodiments of the fuel injector 1, the pilot control valve body 210 is provided with a guiding hole 2120; the guiding hole 2120 is adapted to the armature 222 to guide the movement direction of the armature 222; the guiding 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 in fluid communication with each other, jointly constituting the control cavity; by arranging the guiding hole 2120 and the spring cavity 211 both in the pilot control valve body 210, the oil outlet hole 214 can be configured as a shorter flow path, thereby facilitating reducing the oil delivery distance and improving the control response speed, etc.; the control oil cavity 213 is further connected to a pressure relief cavity 216, and the fluid communication between the control oil cavity 213 and the pressure relief cavity 216 is realized through the opening and closing of the pilot control valve assembly 20; for example, the armature 222 and the valve port can be sealingly matched, and by controlling the movement of the armature 222, the valve port between the control oil cavity 213 and the pressure relief cavity 216 is opened or closed; when the pilot control valve assembly 20 is opened, the control oil cavity 213 and the pressure relief cavity 216 are in fluid communication, and the control oil flows out from the spring cavity 211 through the oil outlet hole 214 and the control oil cavity 213 and out from the pressure relief cavity 216, so that the inside of the control cavity is depressurized; specifically, it can also be configured that the pressure relief cavity 213 is jointly constituted by the end faces of the pilot control valve body 210 and the needle valve body 110, so that the pilot control valve assembly 20 and the needle valve pair 10 are further integrated and are easy to process and manufacture, etc.; compared with the traditional pilot valve assembly configured with an independent guiding structure and an orifice plate, by arranging the control oil cavity 213 in the guiding hole 2120 and opening the oil outlet hole 214, the structures and functions of the traditional guiding structure and the orifice plate are integrated into one, the structure is simplified, which is beneficial to the compact design of the fuel injector 1 and the cost is lower.

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

[0049] It can be understood that since the first valve stem 122 is movably received inside the first cavity 1210, there is a certain gap between it and the wall surface of the first cavity 1210, so that 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 be always greater than the clean fuel pressure inside the first cavity 1210, it effectively avoids the leakage of clean fuel from this gap to the control cavity, and further effectively avoids the corrosion of components (such as the electromagnet 221) by clean fuel and the pollution of the control oil return, etc.

[0050] As Figure 3 , Figure 4 shown, in one or more embodiments of the fuel injector 1, a guiding section 123 is provided between the first cavity 1210 and the first valve stem 122; in the guiding section 123, the wall surface 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 guiding section 123 is located between the control cavity and the clean fuel storage tank 1211; the guiding section 123 is configured such that when the clean fuel needle valve 120 is opened, the control cavity is sealed for the clean fuel; specifically, it can be achieved by appropriately configuring at least one of the length of the guiding section 123 and the gap between the wall surface of the first cavity 1210 and the first valve stem 122 in the guiding section 123. Such a design is beneficial to ensure that the clean fuel does not leak into the control cavity and improve 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 a magnetic force, and the armature 222 moves under the action of the magnetic force, causing the pilot control valve assembly 20 to open, controlling the oil to flow out from inside the control chamber to relieve pressure; for example, the armature 222 moves (upward movement as shown in the figure), causing the control oil chamber 213 and the pressure relief chamber 216 to be in fluid communication, the control oil flowing out from inside the spring chamber 211, then through the oil discharge orifice 214, flowing to the control oil chamber 213, and then flowing out through the pressure relief chamber 216 and returning oil, etc., to relieve pressure in the control chamber; when the force provided by the clean fuel in the clean fuel storage tank 1211 overcomes the force provided by the control oil inside the control chamber and the spring 14 on the first valve stem 122, the first valve stem 122 moves (upward movement as shown in the figure), causing the clean fuel needle valve 120 to open, and the clean fuel flows from the clean fuel storage tank 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 between the control oil chamber 213 and the pressure relief chamber 216, the control oil flowing from the oil inlet passage 216 to inside the spring chamber 211 to build pressure, and the force provided by the control oil inside the control chamber and the spring 14 on the first valve stem 122 overcomes the force provided by the clean fuel in the clean fuel storage tank 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 to stop.

[0052] As Figure 3 shown, in one or more embodiments of the fuel injector 1, an arc surface structure 111 is provided on the outer side wall surface of the needle valve body 110; specifically, the arc surface structure 111 can be configured to entirely surround the outer side wall surface of the needle valve body 110. The arc surface structure 111 can be used to form a sealing fit with a support structure on the outer peripheral side of the fuel injector 1, etc., to prevent fuel inside the cylinder block from leaking to the outside; compared with the fuel injector 1 without the arc surface structure 111 (as Figure 4 shown), there is no need to configure a separate sealing gasket, 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 chamber 30, and the clean fuel inlet 41 is in fluid communication with the clean fuel accumulator chamber 30. Such a design facilitates the structural arrangement of the cylinder head and the fuel injector 1, as well as the flow path arrangement for the clean fuel to enter the fuel injector 1, making the overall structure of the engine more compact.

[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 only the first fuel 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 only the first fuel 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 pilot fuel for the clean fuel.

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

[0057] By setting the clean fuel accumulator chamber, the pressure fluctuation of the clean fuel during injection can be effectively reduced, the injection stability of the clean fuel can be improved, and the combustion effect can be improved. The principle is that, compared with traditional fuels, clean fuels generally have characteristics such as low calorific value, low viscosity, and low density, which makes the fuel injector face a greater injection volume demand when injecting clean fuel. Furthermore, a large-flow injection requires larger sizes for the internal flow channels and accumulator volume of the injector. Therefore, the clean fuel accumulator chamber is set to increase the accumulator volume of the clean fuel, so that the clean fuel first flows into the interior of the clean fuel accumulator chamber before injection, and the pressure fluctuation is suppressed through accumulation to make the injection stable. On the other hand, as described above, since the injector structure supporting dual-fuel injection is complex and its internal space is extremely limited, and the pilot control valve assembly needs to act on the needle valve pair to control the opening and closing of the clean fuel needle valve, the pilot control valve assembly is arranged in the middle of the injector. Compared with the arrangement scheme where the pilot control valve assembly and the needle valve pair are separated by the clean fuel accumulator chamber, it makes the pilot control valve assembly closer to the needle valve pair, which is more conducive to the compact design of the pilot control valve assembly and can also provide a basis for the integrated structural design between the pilot control valve assembly and the needle valve pair to make more full use of the space, etc.

[0058] Although this application is disclosed above in a preferred embodiment, it is not used to limit this application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of this application. Therefore, all modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of this application without departing from the technical solution of this application shall fall within the protection scope defined by the claims of this application.

Claims

1. A fuel injector (1), characterized in that, Comprising: A needle valve pair (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); A clean fuel accumulator chamber (30); wherein, The clean fuel accumulator chamber (30) is fluidly connected to the needle valve pair (10), such that clean fuel can be pressurized inside the clean fuel accumulator chamber (30) first and then flow out from the needle valve pair (10) for injection; and, the needle valve pair (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).

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

3. The fuel injector (1) according to claim 2, characterized in that, The pilot control valve assembly (20) further includes a pilot control driving part (220) for controlling the pressure of the control oil inside the control cavity; the pilot control driving part (220) includes an electromagnet (221) and an armature (222); when the electromagnet (221) is energized to generate a magnetic force, the armature (222) moves under the action of the magnetic force, such that the pilot control valve assembly (20) is opened, and the control oil flows out from inside the control cavity 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 storage tank (1211); the clean fuel inside the clean fuel storage tank (1211) provides a force for the first valve stem (122) to tend to open the clean fuel needle valve (120).

5. The fuel injector (1) according to claim 1, characterized in that, The needle valve pair (10) further 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 a force for the first valve stem (122).

6. The fuel injector (1) according to claim 3, characterized in that, 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 the control oil cavity (213) and the spring cavity (211) are fluidly connected through an oil discharge amount hole (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 the control oil flows from the spring cavity (211) through the oil discharge amount hole (214) and the control oil cavity (213) to the pressure relief cavity (216), so that the inside of the control cavity is depressurized.

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

8. 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 surface 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 storage tank (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 the clean fuel.

9. 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 a magnetic force, and the armature (222) moves under the action of the magnetic force, so that the pilot control valve assembly (20) is opened, and the control oil flows out from inside the control cavity for pressure relief. When the force tending to close the clean fuel needle valve (120) is reduced until it is overcome by the force tending to open the clean fuel needle valve (120), the clean fuel needle valve (120) is opened, and the 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), and the control oil flows into the control cavity for pressure build-up. When the force tending to close the clean fuel needle valve (120) increases until it overcomes the force tending to open the clean fuel needle valve (120), the clean fuel needle valve (120) is closed, and the first cavity (1210) is closed to the outside.

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

11. The fuel injector (1) according to claim 1, characterized in that, It further includes a clean fuel inlet (41), located at the end of the clean fuel accumulator cavity (30), and the clean fuel inlet (41) is fluidly connected to the clean fuel accumulator cavity (30).

12. An engine, characterized in that, Comprising a fuel injector (1) as described in any one of claims 1 to 11; the fuel injector (1) injects the clean fuel and the 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).

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