Dual-fuel premixing type ejector

Abstract

The invention relates to a dual-fuel premixing type ejector. The valve comprises a valve body. The outer needle is movably connected into an inner cavity of the valve body, a pressure chamber is formed between the head of the outer needle and the end of the inner cavity of the valve body, a first fuel spraying hole used for spraying first fuel is formed in the head of the outer needle, and a second fuel spraying hole used for spraying second fuel is formed in the end of the valve body. The first fuel spray hole and the second fuel spray hole extend into the pressure chamber, and the outer needle head can make contact with or be separated from the end of an inner cavity of the valve body so as to open or close the second fuel spray hole. And the inner needle is movably connected to the interior of the inner cavity of the outer needle, and the head of the inner needle can make contact with or be separated from the end of the inner cavity of the outer needle so as to open or close the first fuel spray hole. The temperature of the head of the fuel nozzle can be effectively reduced, formation of carbon deposition of the nozzle hole is inhibited, and the design and process difficulty is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of injectors, in particular to a dual-fuel premixing injector. Background Art

[0002] As one of the alternative fuels, natural gas has developed rapidly in the transportation field in recent years due to its good cleanliness and economy, and the sales of gas vehicles have increased year by year. The existing natural gas engines on the market mainly use low-pressure manifold injection technology, which injects natural gas into the intake manifold at a pressure below 10 bar and ignites it through spark plugs, but its calorific value efficiency is low and the exhaust temperature is high. In order to solve the above problems, Westport Innovations in Canada proposed HPDI technology, which uses a dual-fuel injector to directly inject diesel and natural gas into the combustion chamber at a high pressure of 300 bar, injects a small amount of diesel to ignite it, and then injects 95% of natural gas as the main fuel to burn and do work.

[0003] Most of the existing dual-fuel injectors use two sets of spray holes to directly spray two fuels into the combustion chamber. In order to ensure efficient combustion, the axial and circumferential relative positions of the two sets of fuel spray holes need to be designed according to the structure of the engine combustion chamber, which has high requirements for design and process. At the same time, since the fuel spray hole that plays the role of ignition requires a small injection volume, it is inevitable to use a smaller diameter size, which is very easy to form carbon deposits in the high temperature environment of the engine combustion chamber and block the spray hole. Summary of the invention

[0004] To this end, the present invention provides a dual-fuel premixing injector, which can effectively reduce the temperature of the fuel nozzle head, inhibit the formation of carbon deposits in the spray hole, and reduce the difficulty of design and process.

[0005] In order to solve the above technical problems, the present invention provides a dual-fuel premixing injector, comprising: Valve body; an outer needle, movably connected to the inner cavity of the valve body, a pressure chamber is formed between the head of the outer needle and the inner cavity end of the valve body, the head of the outer needle is provided with a first fuel injection hole for injecting a first fuel, and the end of the valve body is provided with a second fuel injection hole for injecting a second fuel, the first fuel injection hole and the second fuel injection hole both extend into the pressure chamber, and the head of the outer needle can contact or separate from the inner cavity end of the valve body to open or close the second fuel injection hole; The inner needle is movably connected to the inner cavity of the outer needle, and the head of the inner needle can contact or separate from the inner cavity end of the outer needle to open or close the first fuel injection hole.

[0006] In one embodiment of the present invention, it further comprises an injection body and an intermediate body, wherein the intermediate body is arranged between the injection body and the valve body; The injection body is provided with a first fuel inlet and a second fuel inlet; A first fuel channel and a second fuel channel are respectively provided between the injection body, the intermediate body and the valve body; A first fuel injection chamber is formed between the inner needle and the outer needle, and a second fuel injection chamber is formed between the outer needle and the valve body; The first fuel injection chamber is communicated with the first fuel inlet through a first fuel passage, and the first fuel inlet is connected to a first fuel rail. The second fuel injection chamber is communicated with the second fuel inlet through a second fuel passage, and the second fuel inlet is connected to a second fuel rail.

[0007] In one embodiment of the present invention, it further comprises an inner needle spring, a travel screw and an outer needle spring, wherein the travel screw is threadedly connected to the tail of the outer needle; The inner needle spring is arranged between the inner needle and one end of the travel screw to provide a force for the inner needle to move away from the travel screw; The outer needle spring is disposed between the intermediate body and the other end of the travel screw to provide a force for the travel screw to move away from the intermediate body.

[0008] In one embodiment of the present invention, the inner needle side wall is provided with a limiting step, an inner needle spring adjustment gasket is provided on the limiting step, and two ends of the inner needle spring are respectively against the travel screw and the inner needle spring adjustment gasket.

[0009] In one embodiment of the present invention, a first control chamber is formed between the tail of the inner needle and the travel screw; The intermediate body is provided with a first oil inlet hole, and the first control chamber is communicated with the first fuel inlet through the first oil inlet hole.

[0010] In one embodiment of the present invention, a first fuel actuating mechanism is disposed on the injection body, a first oil outlet channel is disposed between the intermediate body and the injection body, and the first control chamber is connected to the first fuel actuating mechanism through the first oil outlet channel.

[0011] In one embodiment of the present invention, the travel screw radially extends to have a limiting boss that can abut against the tail of the outer needle, the intermediate body is provided with a accommodating groove, an outer needle spring adjustment gasket is arranged on the limiting boss, and the two ends of the outer needle spring respectively abut against the bottom wall of the accommodating groove and the outer needle spring adjustment gasket.

[0012] In one embodiment of the present invention, a second control chamber is formed between the travel screw and the accommodation groove; The intermediate body is provided with a second oil inlet hole, and the second control chamber is communicated with the second fuel inlet through the second oil inlet hole.

[0013] In one embodiment of the present invention, a second fuel actuating mechanism is disposed on the injection body, a second oil outlet passage is disposed between the intermediate body and the injection body, and the second control chamber is connected to the second fuel actuating mechanism through the second oil outlet passage.

[0014] In one embodiment of the present invention, it further includes a hydraulic fluid exhaust passage connected to the first fuel actuating mechanism and the second fuel actuating mechanism, respectively.

[0015] The above technical solution of the present invention has the following advantages compared with the prior art: The dual-fuel premixing injector of the present invention places the spray hole of the first fuel in the pressure chamber of the second fuel, so that the spray hole of the first fuel is far away from the burning flame, which helps to reduce the temperature of the nozzle head of the first fuel and inhibits the formation of carbon deposits in the spray hole; When designing the injector for engine matching, only the matching relationship between a set of nozzle holes and the combustion chamber needs to be considered, which effectively reduces the difficulty of design and process.

[0016] Although the first fuel of the injector is located in the pressure chamber of the second fuel, an independent injection device is still used, and the injection amount can be accurately controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0018] Figure 1 It is a structural schematic diagram of the dual-fuel premixing injector of the present invention.

[0019] Description of the Figures in the Specification: 1. Injector body; 2. Intermediate body; 3. Valve body; 4. Outer needle; 5. Inner needle; 6. Inner needle spring adjustment gasket; 7. Inner needle spring; 8. Stroke screw; 9. Outer needle spring adjustment gasket; 10. Outer needle spring; 11. First fuel actuation mechanism; 12. Second fuel actuation mechanism; 13. First fuel inlet; 14. Second fuel inlet; 15. Hydraulic fluid discharge channel; 16. First fuel spray hole; 17. Second fuel spray hole; 18. Pressure chamber; 19. First control chamber; 20. First oil inlet; 21. First fuel injection chamber; 22. First fuel channel; 23. Second control chamber; 24. Second oil inlet; 25. Second fuel injection chamber; 26. Second fuel channel; 27. First oil outlet channel; 28. Second oil outlet channel. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0021] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0022] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0023] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0024] Reference Figure 1 As shown, a dual-fuel premixing injector of the present invention comprises: Valve body 3; An outer needle 4 is movably connected to the inner cavity of the valve body 3, a pressure chamber 18 is formed between the head of the outer needle 4 and the inner cavity end of the valve body 3, a first fuel injection hole 16 for injecting a first fuel is provided at the head of the outer needle 4, and a second fuel injection hole 17 for injecting a second fuel is provided at the end of the valve body 3, the first fuel injection hole 16 and the second fuel injection hole 17 both extend into the pressure chamber 18, and the head of the outer needle 4 can contact or separate from the inner cavity end of the valve body 3 to open or close the second fuel injection hole 17; The inner needle 5 is movably connected to the inner cavity of the outer needle 4 , and the head of the inner needle 5 can contact or separate from the inner cavity end of the outer needle 4 to open or close the first fuel injection hole 16 .

[0025] Through the above arrangement, the nozzle of the first fuel is placed in the pressure chamber 18 of the second fuel, so that the first fuel nozzle 16 is away from the burning flame, which helps to reduce the temperature of the first fuel nozzle head. From a functional point of view, the first fuel is injected into the pressure chamber 18 of the second fuel. When the second fuel enters the pressure chamber 18, the two fuels are premixed and ejected together with the injection of the second fuel. When matching the design with the engine, only one set of nozzles and the combustion chamber need to be considered, which can effectively reduce the difficulty of design and process.

[0026] Specifically, it also includes an injection body and an intermediate body 2, the intermediate body 2 is arranged between the injection body and the valve body 3; the injection body is provided with a first fuel inlet 13 and a second fuel inlet 14; the injection body, the intermediate body 2 and the valve body 3 are respectively provided with a first fuel channel 22 and a second fuel channel 26; a first fuel injection chamber 21 is formed between the inner needle 5 and the outer needle 4, and a second fuel injection chamber 25 is formed between the outer needle 4 and the valve body 3; the first fuel injection chamber 21 is connected to the first fuel inlet 13 through the first fuel channel 22, and the first fuel inlet 13 is connected to the first fuel rail, and the second fuel injection chamber 25 is connected to the second fuel inlet 14 through the second fuel channel 26, and the second fuel inlet 14 is connected to the second fuel rail.

[0027] Specifically, it also includes an inner needle spring 7, a travel screw 8 and an outer needle spring 10. The travel screw 8 is threadedly connected to the tail of the outer needle 4; the inner needle spring 7 is arranged between the inner needle 5 and one end of the travel screw 8 to provide a force for the inner needle 5 to move away from the travel screw 8; the outer needle spring 10 is arranged between the intermediate body 2 and the other end of the travel screw 8 to provide a force for the travel screw 8 to move away from the intermediate body 2.

[0028] Specifically, a limiting step is provided on the side wall of the inner needle 5 , an inner needle spring adjusting gasket 6 is provided on the limiting step, and two ends of the inner needle spring 7 are respectively against the travel screw 8 and the inner needle spring adjusting gasket 6 .

[0029] Specifically, a first control chamber 19 is formed between the tail of the inner needle 5 and the travel screw 8; the intermediate body 2 is provided with a first oil inlet hole 20, and the first control chamber 19 is connected to the first fuel inlet 13 through the first oil inlet hole 20. Optionally, a first oil outlet hole is provided at any position between the first control chamber 19 and the first fuel actuating mechanism 11.

[0030] Specifically, a first fuel actuating mechanism 11 is disposed on the injection body, a first oil outlet passage 27 is disposed between the intermediate body 2 and the injection body, and the first control chamber 19 is connected to the first fuel actuating mechanism 11 through the first oil outlet passage 27 .

[0031] Specifically, the travel screw 8 radially extends with a limiting boss that can abut against the tail of the outer needle 4, the intermediate body 2 is provided with a accommodating groove, and an outer needle spring adjustment gasket 9 is arranged on the limiting boss, and the two ends of the outer needle spring 10 respectively abut against the bottom wall of the accommodating groove and the outer needle spring adjustment gasket 9.

[0032] Specifically, a second control chamber 23 is formed between the travel screw 8 and the accommodating groove; the intermediate body 2 is provided with a second oil inlet hole 24, and the second control chamber 23 is connected with the second fuel inlet 14 through the second oil inlet hole 24. Optionally, a second oil outlet hole is provided at any position between the second control chamber 23 and the second fuel actuating mechanism 12.

[0033] Specifically, the injection body is provided with a second fuel actuating mechanism 12 , a second oil outlet passage 28 is provided between the intermediate body 2 and the injection body, and the second control chamber 23 is connected with the second fuel actuating mechanism 12 through the second oil outlet passage 28 .

[0034] Specifically, it also includes a hydraulic fluid discharge passage 15 connected to the first fuel actuating mechanism 12 and the second fuel actuating mechanism 12 respectively.

[0035] Working principle: This is a dual fuel premixed injection dual fuel injector, the first fuel is injected into the pressure chamber 18 of the second fuel, when the second fuel enters the pressure chamber 18, the two fuels are premixed and ejected together with the injection of the second fuel. The opening and closing of the outer needle 4 is controlled by the change of the liquid pressure in the second control chamber 23, and the opening and closing of the inner needle 5 is controlled by the change of the liquid pressure in the first control chamber 19.

[0036] When the first fuel actuating mechanism 11 is not working, the pressure in the first control chamber 19 is equal to the first fuel rail pressure. Under the combined force of the spring preload of the inner needle spring 7, the downward hydraulic pressure of the control chamber and the upward hydraulic pressure of the first fuel injection chamber 21, the lower end of the inner needle 5 is pressed against the outer needle 4.

[0037] When the first fuel actuator 11 is working, the discharge channel opens, and the hydraulic fluid in the first control chamber 19 flows out from the hydraulic fluid discharge channel 15, and the pressure in the first control chamber 19 drops. When the pressure in the first control chamber 19 drops to a certain critical value, the upward liquid pressure of the first fuel injection chamber 21 on the inner needle 5 is greater than the combined force of the downward liquid pressure of the first control chamber 19 and the downward preload of the inner needle spring 7, so that the inner needle 5 moves upward, the first fuel injection valve opens, and the dual fuel injector injects the first fuel into the pressure chamber 18 through the first fuel nozzle 16.

[0038] When the first fuel actuating mechanism 11 stops working, the hydraulic fluid discharge passage 15 is closed, and the pressure in the first control chamber 19 is re-established to be equivalent to the first fuel rail pressure. When the upward hydraulic pressure of the first fuel injection chamber 21 on the inner needle 5 is less than the combined force of the downward hydraulic pressure of the first control chamber 19 and the downward preload of the inner needle spring 7, the inner needle 5 moves downward, the first fuel injection valve is closed, and fuel injection ends.

[0039] When the second fuel actuating mechanism 12 is not working, the pressure in the second control chamber 23 is equal to the first fuel rail pressure. Under the combined force of the spring preload of the outer needle spring 10, the downward hydraulic pressure of the second control chamber 23 and the upward hydraulic pressure of the second fuel injection chamber 25, the lower end of the outer needle 4 is pressed against the valve body 3.

[0040] When the second fuel actuator 12 is working, the discharge channel opens, the liquid in the second control chamber 23 flows out from the hydraulic fluid discharge channel 15, and the pressure in the second control chamber 23 drops. When the pressure in the second control chamber 23 drops to a certain critical value, the upward liquid pressure of the second fuel injection chamber 25 on the outer needle 4 is greater than the combined force of the downward liquid pressure of the second control chamber 23 and the downward preload of the outer needle spring 10, so that the outer needle 4 moves upward, the second fuel injection valve opens, and the second fuel enters the pressure chamber 18 to be premixed with the first fuel in the pressure chamber 18. The premixed fuel is sprayed into the engine combustion chamber through the second fuel nozzle 17.

[0041] When the second fuel actuation mechanism 12 stops working, the hydraulic fluid discharge passage 15 is closed, and the pressure in the control chamber is re-established to be equivalent to the first fuel rail pressure. When the upward hydraulic pressure of the second fuel injection chamber 25 on the outer needle 4 is less than the combined force of the downward hydraulic pressure of the second control chamber 23 and the downward preload of the outer needle spring 10, the outer needle 4 moves downward, the second fuel injection valve is closed, and fuel injection ends.

[0042] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A dual fuel premixing injector, characterized in that: include: Valve body (3); An outer needle (4) is movably connected to the inner cavity of the valve body (3), a pressure chamber (18) is formed between the head of the outer needle (4) and the inner cavity end of the valve body (3), the head of the outer needle (4) is provided with a first fuel spray hole (16) for spraying a first fuel, and the end of the valve body (3) is provided with a second fuel spray hole (17) for spraying a second fuel, the first fuel spray hole (16) and the second fuel spray hole (17) both extend into the pressure chamber (18), and the head of the outer needle (4) can contact or separate from the inner cavity end of the valve body (3) to open or close the second fuel spray hole (17); An inner needle (5) is movably connected to the inner cavity of the outer needle (4), and the head of the inner needle (5) can contact or separate from the inner cavity end of the outer needle (4) to open or close the first fuel injection hole (16).

2. A dual fuel premixing injector according to claim 1, characterized in that: It also comprises an injection body and an intermediate body (2), wherein the intermediate body (2) is arranged between the injection body and the valve body (3); The injection body is provided with a first fuel inlet (13) and a second fuel inlet (14); A first fuel channel (22) and a second fuel channel (26) are respectively provided between the injection body, the intermediate body (2) and the valve body (3); A first fuel injection chamber (21) is formed between the inner needle (5) and the outer needle (4), and a second fuel injection chamber (25) is formed between the outer needle (4) and the valve body (3); The first fuel injection chamber (21) is connected to the first fuel inlet (13) through a first fuel channel (22), and the first fuel inlet (13) is connected to a first fuel rail. The second fuel injection chamber (25) is connected to the second fuel inlet (14) through a second fuel channel (26), and the second fuel inlet (14) is connected to a second fuel rail.

3. A dual fuel premixing injector according to claim 2, characterized in that: It also includes an inner needle spring (7), a travel screw (8) and an outer needle spring (10), wherein the travel screw (8) is threadedly connected to the tail of the outer needle (4); The inner needle spring (7) is arranged between the inner needle (5) and one end of the travel screw (8) to provide a force for the inner needle (5) to move away from the travel screw (8); The outer needle spring (10) is arranged between the intermediate body (2) and the other end of the travel screw (8) to provide a force for the travel screw (8) to move away from the intermediate body (2).

4. A dual fuel premixing injector according to claim 3, characterized in that: The side wall of the inner needle (5) is provided with a limit step, and an inner needle spring adjustment gasket (6) is provided on the limit step. The two ends of the inner needle spring (7) are respectively against the travel screw (8) and the inner needle spring adjustment gasket (6).

5. A dual fuel premixing injector according to claim 3, characterized in that: A first control chamber (19) is formed between the tail of the inner needle (5) and the travel screw (8); The intermediate body (2) is provided with a first oil inlet hole (20), and the first control chamber (19) is connected to the first fuel inlet (13) through the first oil inlet hole (20).

6. A dual fuel premixing injector according to claim 5, characterized in that: A first fuel actuating mechanism (11) is provided on the injection body, a first oil outlet passage (27) is provided between the intermediate body (2) and the injection body, and the first control chamber (19) is connected to the first fuel actuating mechanism (11) via the first oil outlet passage (27).

7. A dual fuel premixing injector according to claim 6, characterized in that: The travel screw (8) is radially extended with a limiting boss capable of abutting against the tail of the outer needle (4), the intermediate body (2) is provided with a receiving groove, an outer needle spring adjustment gasket (9) is arranged on the limiting boss, and the two ends of the outer needle spring (10) are respectively abutted against the bottom wall of the receiving groove and the outer needle spring adjustment gasket (9).

8. A dual fuel premixing injector according to claim 7, characterized in that: A second control chamber (23) is formed between the travel screw (8) and the accommodating groove; The intermediate body (2) is provided with a second oil inlet hole (24), and the second control chamber (23) is connected to the second fuel inlet (14) through the second oil inlet hole (24).

9. A dual fuel premixing injector according to claim 8, characterized in that: A second fuel actuating mechanism (12) is provided on the injection body, a second oil outlet passage (28) is provided between the intermediate body (2) and the injection body, and the second control chamber (23) is connected to the second fuel actuating mechanism (12) via the second oil outlet passage (28).

10. A dual fuel premixing injector according to claim 9, characterized in that: It also includes a hydraulic fluid discharge passage (15) connected to the first fuel actuating mechanism (12) and the second fuel actuating mechanism (12), respectively.

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