Single needle valve main auxiliary multi-hole nozzle fuel injector, fuel supply system and engine

Abstract

A single-needle valve multi-orifice fuel injector is provided, comprising a needle valve and a first piston. The first piston moves axially along the needle valve. The injector also includes a main injection orifice, an auxiliary injection orifice, a control oil circuit, and a needle valve limiting structure. The main injection orifice and the auxiliary injection orifice are sequentially arranged at the injector nozzle with a height difference. The first control chamber of the needle valve limiting structure is located above the first piston and is closably connected to the control oil circuit. The storage state of the control oil in the first control chamber determines the lift position of the first piston, which in turn determines the lift position of the needle valve, thereby enabling parallel or single release of the main injection orifice and the auxiliary injection orifice. The above-mentioned single-needle valve multi-orifice fuel injector can simultaneously achieve parallel or single release of main fuel injection and micro-ignition fuel injection under single-needle valve conditions. A fuel supply system and an engine are also provided.

Description

Technical Field

[0001] This invention relates to the field of engines, and more specifically to the field of multi-hole fuel injectors. Background Technology

[0002] The combustion systems of existing intake manifold premixed dual-fuel engines are mainly divided into two categories. The first category, exemplified by the MAN L23 / 30DF and L28 / 32DF, involves fuel injection via the main injection valve in fuel mode. In gas mode, the same injection valve is used to inject pilot fuel, meaning that no additional injectors, pumps, or piping are required in gas mode. The second category consists of a main injector / needle valve with a larger flow rate and a separate micro-ignition injector / needle valve with a smaller flow rate.

[0003] However, existing dual-fuel engine fuel systems have some drawbacks. In the single injector / single needle valve mode, the nozzle is designed for full-power operation in fuel mode, which is unstable at low injection volumes, so it cannot achieve stable operation of low-carbon fuel in gas fuel mode under all operating conditions. In the dual injector / dual needle valve mode, stable operation of gas mode under all operating conditions can be achieved due to the use of separate micro-ignition injectors / needle valves, but additional needle valve structures are required inside the injectors, and additional pumps and pipes are required externally, which increases the cost of engine use and maintenance. Summary of the Invention

[0004] One object of the present invention is to provide a single needle valve main and auxiliary multi-hole fuel injector that can achieve parallel release or single release of main fuel injection and micro-ignition fuel injection under the condition of a single needle valve.

[0005] To achieve the above objectives, a single-needle valve multi-orifice injector includes a needle valve and a first piston. The first piston moves axially along the needle valve. The injector also includes a main injection orifice, an auxiliary injection orifice, a control oil circuit, and a needle valve limiting structure. The main injection orifice and the auxiliary injection orifice are sequentially arranged at the injector nozzle with a height difference. The first control chamber of the needle valve limiting structure is located above the first piston and is closably connected to the control oil circuit. The storage state of the control oil in the first control chamber determines the lift position of the first piston, which in turn determines the lift position of the needle valve, thereby enabling the parallel release or single release of the main injection orifice and the auxiliary injection orifice.

[0006] In one or more embodiments, the needle valve limiting structure further includes a second control chamber, a first elastic element, and an oil drain passage, wherein the first piston and a portion of the needle valve are located in the second control chamber, the second control chamber is connected to the oil drain passage, and the first elastic element connects the needle valve and the first piston.

[0007] In one or more embodiments, the needle valve limiting structure further includes a second elastic element for connecting the first piston and the first control chamber, wherein the force exerted by the second elastic element on the first piston is less than the force exerted by the first elastic element on the first piston.

[0008] In one or more embodiments, the control oil circuit includes a first control oil circuit, a second control oil circuit, and a control oil drain circuit. The injector also includes a second piston. The first control chamber is closably connected to the first control oil circuit and closably connected to the control oil drain circuit.

[0009] In one or more embodiments, the injector further includes a second piston and a third elastic element, the third elastic element being used to apply a thrust in a first direction to the second piston, the second piston being configured to be pushed by controlled oil pressure to overcome the elastic force of the third elastic element and move in a direction opposite to the first direction, thereby blocking the first control chamber and the control oil drain passage.

[0010] In one or more embodiments, the first control chamber is closably connected to the first control oil passage and the control oil drain passage via a valve or electromagnetic component.

[0011] In one or more embodiments, the injector further includes a needle valve pressure chamber for receiving high-pressure oil, which in turn pushes the needle valve upward by means of the high pressure within the chamber.

[0012] In one or more embodiments, the needle valve is a hollow needle valve, and the outer wall surface of the hollow needle valve is in a relatively sealing fit with the injector nozzle.

[0013] In one or more embodiments, the main injection port is located above the auxiliary injection port and is used to provide a large volume of main fuel injection, while the auxiliary injection port is used to provide a spray.

[0014] Another object of the present invention is to provide a fuel supply system using the above-described single needle valve main and auxiliary multi-hole injector.

[0015] Another object of the present invention is to provide an engine using the above-described fuel supply system.

[0016] The aforementioned single-needle valve main and auxiliary multi-hole injector, by setting a main and auxiliary injection hole structure and utilizing the multi-lift structure design of the first piston, achieves parallel or single release of the main and auxiliary injection holes under the condition of a single-needle valve injector by adjusting the lift position of the single needle valve. This allows the injector to balance the injection stability of large main injection volume and small micro-ignition volume, improve the substitution rate of low-carbon fuels, and thus reduce carbon emissions. At the same time, the structure is simple, does not require many auxiliary parts, and is easy to manufacture. Attached Figure Description

[0017] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0018] Figure 1 This is a structural cross-sectional view of an embodiment of a needle valve main and auxiliary multi-hole injector;

[0019] Figure 2 This is a schematic diagram showing the position of the main and auxiliary nozzles when the first piston is in the first lift position and the nozzles are in the closed state.

[0020] Figure 3 This is a schematic diagram showing the positions of the main and auxiliary nozzles when they are fully open;

[0021] Figure 4 This is a schematic diagram showing the position of the main and auxiliary nozzles when the first piston is in the second stroke position and the nozzles are closed.

[0022] Figure 5 This is a schematic diagram showing the positions of the main and auxiliary nozzles when they are fully open.

[0023] Symbol marking explanation

[0024] 10. Needle valve

[0025] 11. Needle valve pressure chamber

[0026] 12. Check valve

[0027] 13. Third elastic element

[0028] 14. Second Piston

[0029] 15. First control chamber

[0030] 16. Second control chamber

[0031] 17. First elastic element

[0032] 18. Oil drain line

[0033] 19. Second elastic element

[0034] 20. First Piston

[0035] 23. High-pressure oil inlet hole

[0036] 31. Main nozzle hole

[0037] 32. Auxiliary spray nozzle

[0038] 40. Control the oil circuit

[0039] 41. Control oil first oil circuit

[0040] 42. Control oil second oil circuit

[0041] 43. Control the oil drain circuit Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0043] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0044] Combination Figure 1 As shown, the single-needle valve main and auxiliary multi-hole nozzle injector includes a needle valve 10 and a first piston 20, which moves along the axial direction of the needle valve 10. Similar to the structure of a conventional injector, this injector also includes a needle valve pressure chamber 11, which receives high-pressure oil from the high-pressure oil inlet 23 and then applies force to the conical surface of the needle valve by the hydraulic pressure inside the chamber, pushing the needle valve 10 upward.

[0045] The injector also includes a main injection hole 31 and an auxiliary injection hole 32, a control oil passage 40, and a needle valve limiting structure. The main injection hole 31 and the auxiliary injection hole 32 are arranged sequentially at the injector nozzle with a height difference. The main injection hole 31 provides a large volume of main fuel injection, offering advantages such as a long spray penetration distance and high cylinder space utilization. The auxiliary injection hole 32 provides a micro-injection of fuel, offering advantages such as excellent atomization quality and a short ignition delay. The main and auxiliary injection holes are not limited to the two rows shown in the figure; those skilled in the art will understand that multiple rows of injection holes with a height difference can also be configured. In some embodiments, the main injection hole 31 is positioned above the auxiliary injection hole 32.

[0046] The needle valve limiting structure is used to control the lift of the needle valve. It includes a first control chamber 15, which is located above the first piston 20 and is closably connected to the control oil circuit 40. The storage state of the control oil in the first control chamber 15 determines the lift position of the first piston 20, and thus the lift position of the needle valve 10, thereby enabling the parallel or single release of the main nozzle 31 and the auxiliary nozzle 32. By using the control oil circuit to control the lift position of the first piston 20, the lifting position of the needle valve 10 is controlled, thus determining the opening state of the main nozzle 31 and the auxiliary nozzle 32 with different heights.

[0047] In some embodiments, the needle valve limiting structure further includes a second control chamber 16, a first elastic element 17, and an oil drain passage 18. A portion of the first piston 20 and the needle valve 10 are located within the second control chamber 16, which communicates with the oil drain passage 18. The first elastic element 17 connects the needle valve 10 and the first piston 20. The needle valve limiting structure also includes a second elastic element 19 connecting the first piston 20 and the first control chamber 15. The force exerted by the second elastic element 19 on the first piston 20 is less than the force exerted by the first elastic element 17 on the first piston 20, thereby ensuring that the first piston 20 is at a higher stroke when control oil is not flowing into the control oil passage 40.

[0048] The control oil circuit 40 includes a first control oil circuit 41, a second control oil circuit 42, and a control oil drain circuit 43. The first control chamber 15 is closably connected to the first control oil circuit 41 and closably connected to the control oil drain circuit 43.

[0049] If passed Figure 1 The cooperation between the second piston 14 and the third elastic element 13 controls the opening and closing of the first control chamber and the control oil drain passage 43. The third elastic element 13 applies a thrust in a first direction to the second piston 14. The second piston 14 is configured to be pushed by the control oil pressure to overcome the elastic force of the third elastic element 13 and move in the opposite direction to the first direction, thereby blocking the first control chamber 15 and the control oil drain passage 43. When pressurized control oil is introduced into the control oil passage, firstly, the second control oil passage 42 acts on the large-area piston surface on the right side of the second piston. The force of the oil pressure on the second piston 14 is greater than the elastic force of the third elastic element 13, and the second piston 14 moves to the left. The small cylindrical surface of the second piston 14 blocks the control oil drain passage 14, thus closing the first control chamber 15. At the same time, the control oil enters the first control chamber 15 through the second control oil circuit, through the one-way valve 12, through the flow channel of the first piston 20 and the top surface of the injector body. Due to the presence of control oil pressure, the combined force formed by the control oil pressure and the second elastic element 19 moves the first piston 20 down to the second limit L2.

[0050] In other embodiments, the first control chamber 15 is closably connected to the first control oil passage 41 and the control oil drain passage 43 via a valve or electromagnetic assembly, such as through an electromagnetic armature to achieve on / off connectivity. In some embodiments, the first control oil passage 41 is connected via... Figure 1 The one-way valve 12 shown includes a ball, a sealing cone, a spring, and an associated washer, which allows control oil to flow into the first control chamber 15 through the first control oil passage 41 and does not allow backflow.

[0051] To ensure that the lift position of the needle valve can control the selective release of the main injection port 31 and the auxiliary injection port 32, in some embodiments, the needle valve is a hollow needle valve. The outer wall of the hollow needle valve is in a relatively sealed fit with the injector nozzle to ensure that fuel flows only below the needle valve.

[0052] The influence of the control oil circuit on the first piston 20 and needle valve 10 is referenced. Figures 2 to 5 understand.

[0053] Figure 2 In the indicated state, control oil is not supplied to the first control oil passage 41 and the second control oil passage 42, and control oil does not exert force on the second piston 14 and the first piston 20. The second piston 14 is subjected to the elastic force of the third elastic element 13, and... Figure 2 As shown in the right-hand movement, the second piston 14 does not block the control oil drain hole. No force is applied to the control oil in the first control chamber 15, and the force on the first piston 20 is relatively small. At this time, the first piston 20 is simultaneously subjected to the elastic forces of the first elastic element 17 and the second elastic element 19, but the force exerted by the second elastic element 19 on the first piston 20 is less than the force exerted by the first elastic element 17 on the first piston 20. Therefore, the first piston 20 is located in a higher lift position, such as... Figure 2 The first lift position L1 is shown.

[0054] When high-pressure oil does not flow into the pressure chamber 11 of the needle valve, the lower conical surface of the needle valve 10 experiences relatively little force. The force applied to the needle valve 10 by the first elastic element 17 is balanced with the force applied to the conical surface of the needle valve by the hydraulic pressure in the pressure chamber 11. The combined force of the elastic force applied to the first piston 20 by the second elastic element 19 and the force applied to the first piston 20 by the hydraulic pressure in the first control chamber 15 is balanced with the force applied to the first piston 20 by the first elastic element 17. At this time, both the main nozzle 31 and the auxiliary nozzle 32 are closed.

[0055] Figure 3 The diagram shows that after the high-pressure fuel enters, the high-pressure fuel in the needle valve pressure chamber 11 exerts an upward thrust on the needle valve, causing the needle valve 10 to rise against the elastic force of the first elastic element 17, and the fuel in the second control chamber 16 to be compressed. The drain oil passage 18 is used to discharge the fuel in the second control chamber 16. Since no control oil is supplied, the first piston 20 is in the first lift position L1. After the top of the needle valve 10 gradually rises and contacts the first piston 20, the top of the needle valve 10 is in the first lift position H1, and the end of the needle valve 10 is in position h1. The end lift position h1 of the needle valve 10 is relatively high, thus achieving simultaneous opening of the main injection port 31 and the auxiliary injection port 32. High-pressure fuel flows from the fuel passage in the lower part of the needle valve into the lower pressure chamber, and from the pressure chamber, through the main injection port 31 and the auxiliary injection port 32, is injected outwards. When the main injection port 31 injects the main liquid fuel, the jet flame from the auxiliary injection port 32 can play a role in combustion assistance, improving combustion efficiency.

[0056] Figure 4 and Figure 5 This diagram shows the positions of components when the control oil circuit is open. Figure 4 In the middle, control oil is supplied to the first control oil passage 41 and the second control oil passage 42. Under the influence of the control oil pressure, the second piston 14 moves along... Figure 4 The piston moves to the left and overcomes the elastic force of the third elastic element 13, thereby blocking the oil drain hole and preventing the control oil in the first control chamber 15 from flowing into the control oil drain passage 43. The control oil flows through the first control oil passage 41, through the one-way valve 12, through the flow channel on the top surface of the first piston 20 and the injector body, and then into the first control chamber 15, filling the first control chamber 15. The influence of hydraulic pressure on the first piston 20 increases, and the combined force of the hydraulic thrust on the first piston 20 and the elastic force of the second elastic element 19 on the first piston 20 gradually exceeds the force of the first elastic element 17 on the hydraulic pressure on the first piston 20, pushing the first piston 20 to move downwards. The first piston 20 stops moving after moving downwards to the limit position of the injector body. Figure 4 As shown, at this time, the first piston 20 maintains a position relative to... Figure 2 and Figure 3 The other equilibrium position, which is different from the state shown, has reduced the maximum lift to the second lift position L2.

[0057] Understandably, after the high-pressure fuel is turned on, the high-pressure fuel in the needle valve's pressure chamber 11 exerts an upward thrust on the needle valve, causing the needle valve 10 to rise against the elastic force of the first elastic element 17. For example... Figure 5 As shown, since the first piston 20 is in the lift position L2, and the flow direction of the control oil in the first control chamber via the one-way valve 12 is unidirectional from the control oil circuit 41 to the first chamber 15, the control oil in the first control chamber 15, due to the incompressible nature of liquids, maintains the first piston 20 in the lift position L2. Therefore, the top of the needle valve 10 is at the second lift position H2, and the bottom of the needle valve is at the lift position h2. The lift position h2 is located between the main injection port 31 and the auxiliary injection port 32, achieving a structure where only the lower auxiliary injection port 32 is open while the main injection port 31 is closed. When the dual-fuel engine needs to perform a small amount of diesel injection, the jet flame formed by the diesel fuel ejected from the auxiliary injection port 32 will ignite other fuels in the engine cylinder.

[0058] Therefore, the aforementioned structure controls the position of the first piston to achieve a double lift of the needle valve, thereby enabling the double-layer injection orifice to open as needed. During the entire engine operating cycle, high-pressure fuel is supplied to the high-pressure fuel inlet once, and the needle valve 10 opens and closes once. The control of the main injection orifice 31 and auxiliary injection orifice 32 during the fuel injection process is determined based on the actual fuel combustion requirements and engine operating conditions. When both layers of injection are required, control oil is not supplied; when only the lower layer injection orifice needs to be opened, control oil is supplied.

[0059] Preferably, in the moving parts of the injector, the needle valve 10, the first piston 20, and the second piston 14 are precision pairs with their corresponding mating static parts.

[0060] When the needle valve 10 is in the closed position, in order to prevent fuel leakage, the lower sliding part of the needle valve 10 blocks the main injection hole 31 and the auxiliary injection hole 32. At the same time, the sealing cone surface of the lower part of the needle valve 10 and the sealing seat surface that mates with the fuel nozzle can also ensure that fuel does not leak.

[0061] Currently, the fuel injector is mounted on the engine cylinder head, preferably with the nozzle outlet at the center of the combustion chamber.

[0062] Preferably, the number of main nozzles 31 and auxiliary nozzles 32, the nozzle diameter, and the nozzle angle are designed according to the actual situation of the engine.

[0063] Preferably, the oil pressure of the control oil circuit 40 is selected according to the actual application.

[0064] This structure, when the engine uses fuels other than diesel, utilizes the excellent atomization quality and short ignition delay of the auxiliary nozzle's small orifice to act as pilot fuel in the cylinder of a dual-fuel engine. When diesel is the primary fuel, it leverages the long spray penetration distance and high cylinder space utilization of the main nozzle, supplemented by the short spray penetration distance and excellent atomization of the auxiliary nozzle, thus improving the combustion state of diesel in the cylinder. It simultaneously ensures injection stability for both the large volume of main injection and the small volume of pilot fuel. The multi-orifice composite injector optimizes in-cylinder combustion while fully utilizing the combustion space, thereby improving combustion efficiency and reducing carbon emissions. Furthermore, the structure is relatively simple and requires minimal auxiliary components.

[0065] Based on the above introduction to the single-needle valve main and auxiliary multi-hole fuel injector, it can be understood that a fuel supply system with better combustion effect using the single-needle valve main and auxiliary multi-hole fuel injector, and an engine including the above-mentioned fuel supply system.

[0066] It should be noted that the use of terms such as "first" and "second" to define components in the above description is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning, do not represent primary or secondary, and therefore should not be construed as limiting the scope of protection of this application.

[0067] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0068] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A single-needle valve main and auxiliary multi-hole nozzle injector, comprising a needle valve (10) and a first piston (20), wherein the first piston (20) moves along the axial direction of the needle valve (10), characterized in that, The injector also includes: The main nozzle (31) and the auxiliary nozzle (32) are arranged sequentially at the injector nozzle with a height difference; Control the oil circuit (40); The needle valve limiting structure includes a first control chamber (15), which is located above the first piston (20) and is closably connected to the control oil circuit (40). The storage state of the control oil in the first control chamber (15) determines the lift position of the first piston (20), and thus determines the lift position of the needle valve (10), thereby realizing the parallel release or single release of the main nozzle (31) and the auxiliary nozzle (32). The needle valve (10) is a hollow needle valve, and the outer wall surface of the hollow needle valve is in a relatively sealed fit with the injector nozzle; The control oil circuit (40) includes a first control oil circuit (41), a second control oil circuit (42), and a control oil drain circuit (43). The first control chamber (15) is closably connected to the first control oil circuit (41) and closably connected to the control oil drain circuit (43). The injector also includes a second piston (14) and a third elastic element (13), the third elastic element (13) being used to apply a thrust in a first direction to the second piston (14), the second piston (14) being configured to be pushed by controlled oil pressure to overcome the elastic force of the third elastic element (13) and move in a direction opposite to the first direction, thereby blocking the first control chamber (15) and the control oil drain passage (43).

2. The single-needle valve main and auxiliary multi-hole nozzle injector as described in claim 1, characterized in that, The needle valve limiting structure further includes a second control chamber (16), a first elastic element (17), and an oil drain passage (18). The first piston (20) and a portion of the needle valve (10) are located in the second control chamber (16). The second control chamber (16) is connected to the oil drain passage (18). The first elastic element (17) connects the needle valve (10) and the first piston (20).

3. The single-needle valve main and auxiliary multi-hole nozzle injector as described in claim 2, characterized in that, The needle valve limiting structure also includes a second elastic element (19) connecting the first piston (20) and the first control chamber (15). The force exerted by the second elastic element (19) on the first piston (20) is less than the force exerted by the first elastic element (17) on the first piston (20).

4. The single-needle valve main and auxiliary multi-hole nozzle injector as described in claim 1, characterized in that, The first control chamber (15) is closably connected to the first control oil passage (41) and the control oil drain passage (43) via a valve or electromagnetic component.

5. The single-needle valve main and auxiliary multi-hole nozzle injector as described in claim 1, characterized in that, The injector also includes a needle valve pressure chamber (11), which is used to receive high-pressure oil and then push the needle valve (10) upward by means of the high pressure in the chamber.

6. The single-needle valve main and auxiliary multi-hole nozzle injector as described in claim 1, characterized in that, The main nozzle (31) is located above the auxiliary nozzle and is used to provide a large amount of main fuel injection, while the auxiliary nozzle (32) is used to provide a spray.

7. A fuel supply system, characterized in that, Use the single needle valve main and auxiliary multi-hole nozzle injector as described in any one of claims 1-6.

8. An engine, characterized in that, Use the fuel supply system as described in claim 7.

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