A double needle valve injector

Abstract

The present invention belongs to the technical field of marine oil supply equipment, and discloses a double needle valve injector, which includes a body, the body has a working chamber, a needle valve assembly is arranged in the working chamber, the needle valve assembly includes an inner needle valve and an outer needle valve slidably sleeved on the inner needle valve, the inner needle valve can slide against the working chamber and form an adjustment chamber together with the device, the body is respectively provided with a first through hole and a second through hole, the outer needle valve has a sleeve chamber, the sleeve chamber is provided with a through hole, the sleeve chamber is connected with the first oil injection hole through the through hole, the outer needle valve can be slidably sleeved on the inner needle valve through the sleeve chamber and form a first inner chamber together with the inner needle valve, the first inner chamber can be connected with the first oil injection hole through the through hole, the outer needle valve can slide against the working chamber and form a second inner chamber together with the inner needle valve, the second inner chamber can be connected with the first oil injection hole, and the body is provided with a fifth through hole connected with the second inner chamber. The double needle valve injector provided by the present invention can effectively avoid the mixing of two fuels, and ensure the stable and reliable injection supply of the corresponding fuel.

Description

Technical Field

[0001] The invention relates to the technical field of marine oil supply equipment, in particular to a double needle valve injector. Background Art

[0002] As ship emission standards become increasingly stringent, research on alternative energy sources for marine engines becomes increasingly important. Low-carbon fuel methanol and zero-carbon fuel ammonia, as emerging fuels, can effectively reduce emissions. The preparation technology is relatively mature, the refining process is clean and environmentally friendly, and the market prospects are broad. Relying on the original diesel engine injector structure, the development of dual-fuel injectors that can inject both diesel fuel and alternative fuels such as methanol and ammonia is an important way to use new energy for marine engines.

[0003] At present, when the double-needle valve injector switches the injection fuel, diesel and alternative fuels will be mixed when they share a set of injection pipeline structures, and the mixing ratio cannot be accurately determined. The fuel components injected during the switching are complex, the components injected in each cycle are uneven and inconsistent, the combustion conditions are difficult to predict, and the switching state stability is poor, which in turn leads to difficulties in engine speed regulation. Summary of the invention

[0004] The object of the present invention is to provide a double needle valve injector with a simple structure, which can effectively avoid the mixing of two fuels when switching the injection fuel, and ensure that the injection supply amount of the corresponding fuel is stable and reliable.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A double needle valve injector, comprising:

[0007] The main body has a working chamber, and a first oil injection hole is opened at the bottom of the working chamber;

[0008] A needle valve assembly is arranged in the working chamber, and the needle valve assembly comprises an inner needle valve and an outer needle valve slidably sleeved on the lower end of the inner needle valve; wherein,

[0009] The upper end of the inner needle valve can be slidably abutted against the working chamber and form an adjustment chamber together with the working chamber, and the main body is respectively provided with a first through hole and a second through hole connected to the adjustment chamber; the outer needle valve has a sleeve chamber, and the bottom end of the sleeve chamber is provided with a through hole connected to the working chamber, and the sleeve chamber is connected to the first oil injection hole through the through hole, and the outer needle valve can be slidably sleeved on the lower end of the inner needle valve through the sleeve chamber and form a first inner chamber together with the inner needle valve, the first inner chamber can be connected to the first oil injection hole through the through hole, the sleeve chamber is provided with a third through hole connected to the first inner chamber, and the main body is provided with a fourth through hole connected to the third through hole; the outer needle valve can be slidably abutted against the working chamber and form a second inner chamber together with the working chamber, the second inner chamber can be connected to the first oil injection hole, and the main body is provided with a fifth through hole connected to the second inner chamber;

[0010] The double needle valve injector has a preparatory working condition, a first injection working condition and a second injection working condition; wherein,

[0011] When in the preparatory working condition, the inner needle valve is pressed against the bottom end of the sleeve cavity and blocks the through hole, and the outer needle valve is pressed against the bottom end of the working cavity to block the communication between the second inner cavity and the first oil injection hole;

[0012] When in the first injection working condition, the inner needle valve releases the contact with the sleeve cavity so that the first inner cavity, the through hole and the first oil injection hole are connected, and the outer needle valve is tightly against the bottom end of the working cavity to block the communication between the second inner cavity and the first oil injection hole;

[0013] When in the second injection working state, the inner needle valve is tightly against the bottom end of the sleeve cavity and blocks the through hole, and the outer needle valve is released from the abutment with the working cavity to make the second inner cavity communicate with the first injection hole.

[0014] Preferably, a side wall of the inner needle valve extending into the sleeve cavity has a molding groove, and the molding groove and the sleeve cavity together form the first inner cavity.

[0015] Preferably, the groove wall on the side of the cavity wall of the molding groove facing the sleeve cavity includes a first molding surface and a second molding surface, the first molding surface extends inwardly from the side wall surface of the inner needle valve toward the central axis of the inner needle valve, and the second molding surface is arranged at the inclined end of the first molding surface and extends along the central axis of the inner needle valve.

[0016] Preferably, the bottom end of the inner needle valve is provided with a first conical abutment surface along its own axial direction, and the first conical abutment surface extends inwardly obliquely from the side wall surface of the inner needle valve toward the central axis of the inner needle valve, and the bottom end of the sleeve cavity is provided with a second conical abutment surface along its own axial direction, and the second conical abutment surface extends inwardly obliquely from the cavity wall of the sleeve cavity toward the central axis of the outer needle valve to the port of the through hole; the downward sliding of the inner needle valve can make the first conical abutment surface tightly abut against the second conical abutment surface to seal the through hole.

[0017] Preferably, the working chamber includes a first working chamber, a second working chamber and a third working chamber which are connected in sequence from top to bottom; wherein, the upper end of the inner needle valve can slide against the first working chamber and form the adjustment chamber together with the first working chamber, the outer needle valve can slide against the second working chamber and form the second inner chamber together with the second working chamber, and the first oil injection hole is opened on the third working chamber.

[0018] Preferably, the bottom end of the outer needle valve is provided with a third conical abutment surface along its own axial direction, and the third conical abutment surface extends inwardly from the side wall surface of the outer needle valve toward the central axis of the outer needle valve, and a fourth conical abutment surface is connected between the cavity wall of the second working chamber and the cavity wall of the third working chamber; the inner needle valve drives the outer needle valve to slide downward together, so that the third conical abutment surface can be tightly abutted against the fourth conical abutment surface to block the connection between the second inner cavity and the first oil injection hole.

[0019] Preferably, a second oil injection hole is formed on the fourth conical abutting surface, and the third conical abutting surface is tightly abutted against the fourth conical abutting surface to block the second oil injection hole.

[0020] Preferably, it also includes an elastic member, which is arranged in the working chamber and sleeved on the inner needle valve. The inner needle valve is provided with an abutment portion protruding in the radial direction. The upper end of the elastic member abuts against the inner wall of the working chamber, and the lower end of the elastic member abuts against the abutment portion.

[0021] Preferably, a reversing valve is provided on one side of the fifth through hole, the second fuel source and the inert gas source are respectively connected to two working oil ports of the reversing valve, and the fifth through hole is connected to the oil outlet of the reversing valve.

[0022] Preferably, a first fuel source is disposed on one side of the first through hole, and the first fuel source is connected to the first through hole and the fourth through hole.

[0023] Beneficial effects:

[0024] The double needle valve injector provided by the present invention has a simple and reliable structure. In addition to being injected through the first injection hole, the first fuel and the second fuel each use a set of independent pipeline structures and fuel supply paths, which can effectively avoid the two fuels from mixing when switching the injection fuel, avoid affecting the fuel mixing ratio, ensure that the injection supply amount of the corresponding fuel is stable and reliable, and further ensure the reliable operation of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the double needle valve injector provided by the present invention;

[0026] Figure 2 It is a structural schematic diagram of the main body of the double needle valve injector provided by the present invention;

[0027] Figure 3 It is a structural schematic diagram of the inner needle valve and the outer needle valve of the double needle valve injector provided by the present invention;

[0028] Figure 4 It is a schematic diagram of the structure of the double needle valve injector provided by the present invention after being connected to the working components;

[0029] Figure 5 is a schematic diagram of the double needle valve injector provided by the present invention in a first working state;

[0030] Figure 6 is a schematic diagram of the double needle valve injector provided by the present invention in a second working state;

[0031] Figure 7 is a schematic diagram of the double needle valve injector provided by the present invention in a third working state;

[0032] Figure 8 Schematic diagram of the double needle valve injector provided by the present invention in the fourth working state.

[0033] In the figure:

[0034] 1. Body; 101. First through hole; 1011. First hole portion; 1012. Second hole portion; 1013. Third hole portion; 102. Second through hole; 103. Fourth through hole; 104. Fifth through hole; 11. Working chamber; 111. First working chamber; 112. Second working chamber; 113. Third working chamber; 12. First oil injection hole; 13. Second oil injection hole; 14. Fourth conical abutting surface; 15. Discharge hole;

[0035] 2. inner needle valve; 201. adjustment cavity; 202. first inner cavity; 21. molding groove; 211. first molding surface; 212. second molding surface; 22. first conical abutting surface; 23. abutting portion;

[0036] 3. outer needle valve; 301. second inner cavity; 31. sleeve cavity; 32. through hole; 33. third through hole; 34. second conical abutment surface; 35. third conical abutment surface; 36. lubrication hole;

[0037] 4. Elastic parts;

[0038] 51. First fuel source; 52. Second fuel source; 53. Inert gas source; 54. Reversing valve; 55. Switching valve; 56. Fuel tank. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0040] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0043] Reference Figures 1 to 8As shown, this embodiment provides a double needle valve injector. The double needle valve injector can inject both the first fuel and the second fuel. In this embodiment, the first fuel is set to diesel, and the second fuel is set to clean fuel such as methanol, ammonia, dimethyl ether, etc.

[0044] The double needle valve injector comprises a body 1 and a needle valve assembly, the body 1 having a working chamber 11, a first oil injection hole 12 being provided at the bottom end of the working chamber 11, the needle valve assembly being arranged in the working chamber 11, the needle valve assembly comprising an inner needle valve 2 and an outer needle valve 3 slidably sleeved on the lower end of the inner needle valve 2, the upper end of the inner needle valve 2 being slidably abutted against the working chamber 11 and forming an adjustment chamber 201 together with the working chamber 11, the body 1 being respectively provided with a first through hole 101 and a second through hole 102 communicating with the adjustment chamber 201. The outer needle valve 3 has a sleeve cavity 31, and a through hole 32 communicating with the working cavity 11 is opened at the bottom of the sleeve cavity 31. The sleeve cavity 31 is connected with the first injection hole 12 through the through hole 32. The outer needle valve 3 can be slidably sleeved on the lower end of the inner needle valve 2 through the sleeve cavity 31 and form a first inner cavity 202 together with the inner needle valve 2. The first inner cavity 202 can be connected with the first injection hole 12 through the through hole 32. The sleeve cavity 31 has a third through hole 33 communicating with the first inner cavity 202. The body 1 has a fourth through hole 103 communicating with the third through hole 33. The outer needle valve 3 can slidably abut against the working cavity 11 and form a second inner cavity 301 together with the working cavity 11. The second inner cavity 301 can be connected with the first injection hole 12. The body 1 has a fifth through hole 104 communicating with the second inner cavity 301.

[0045] In this embodiment, the double needle valve injector has a preparatory working condition, a first injection working condition and a second injection working condition. Among them, when the double needle valve injector is in the preparatory working condition, the inner needle valve 2 is tightly against the bottom end of the sleeve cavity 31 and blocks the through hole 32 to block the communication between the first inner cavity 202 and the first injection hole 12. The outer needle valve 3 is tightly against the bottom end of the working cavity 11 to block the communication between the second inner cavity 301 and the first injection hole 12. When the double needle valve injector is in the first injection working condition, the inner needle valve 2 is released from the abutment with the sleeve cavity 31 so that the first inner cavity 202, the through hole 32 and the first injection hole 12 are connected, and the outer needle valve 3 is tightly against the bottom end of the working cavity 11 to block the communication between the second inner cavity 301 and the first injection hole 12. When the double needle valve injector is in the second injection working condition, the inner needle valve 2 is tightly against the bottom end of the sleeve cavity 31 and blocks the through hole 32 to block the communication between the first inner cavity 202 and the first injection hole 12. The outer needle valve 3 is released from contact with the working chamber 11 so that the second inner chamber 301 is communicated with the first oil injection hole 12 .

[0046] In this embodiment, the first fuel can be filled into the adjustment chamber 201 through the first through hole 101, and the second through hole 102 can discharge the first fuel in the adjustment chamber 201 to relieve the pressure of the adjustment chamber 201. The first fuel can be filled into the first inner chamber 202 through the fourth through hole 103 and the third through hole 33 in sequence, and sprayed out through the first spray hole 12 under the first spray condition. Figures 5 to 8 The filling of the A area is shown schematically. The second fuel or inert gas can be filled into the second inner cavity 301 through the fifth through hole 104, and the second fuel can also be sprayed out through the first fuel injection hole 12 under the second injection working condition. Figure 5 to Figure 6 The B area is filled as shown in the figure. The second fuel reference Figures 7 and 8 The area C in the middle is filled as shown.

[0047] In this embodiment, a first fuel source 51 is provided on one side of the first through hole 101, and the first fuel source 51 is connected to the first through hole 101 and the fourth through hole 103. The first fuel source 51 can simultaneously flow the first fuel into the first through hole 101 and the fourth through hole 103, and then fill the first fuel into the adjustment cavity 201 and the first inner cavity 202.

[0048] In this embodiment, a reversing valve 54 is provided on one side of the fifth through hole 104, the second fuel source 52 and the inert gas source 53 are respectively connected to two working oil ports of the reversing valve 54, and the fifth through hole 104 is connected to the oil outlet of the reversing valve 54. By providing the reversing valve 54, the second fuel in the second fuel source or the inert gas in the inert gas source can be selectively introduced into the fifth through hole 104, and then the second fuel or the inert gas can be selectively filled into the second inner cavity 301.

[0049] In this embodiment, when the first fuel needs to be injected, the first fuel is filled into the adjustment chamber 201 and the first inner chamber 202 through the first fuel source 51, and the second through hole 102 is closed. At the same time, the inert gas is filled into the second inner chamber 301 through the fifth through hole 104.

[0050] When the adjustment chamber 201 is filled with the first fuel, the first fuel in the adjustment chamber 201 will generate a first pressure on the inner needle valve 2. Under the action of the first pressure, it can drive the inner needle valve 2 to slide downward relative to the working chamber 11 to press against the bottom end of the sleeve chamber 31 and drive the outer needle valve 3 to slide downward together to press against the bottom end of the working chamber 11.

[0051] When the first inner cavity 202 is filled with the first fuel, the first fuel in the first inner cavity 202 will generate a second pressure on the needle valve assembly. Under the action of the second pressure, the inner needle valve 2 can be driven to slide upward relative to the outer needle valve 3. At the same time, under the interaction of forces, the outer needle valve 3 can be driven to slide downward relative to the inner needle valve 2 to abut against the bottom end of the working cavity 11.

[0052] When the second inner cavity 301 is filled with inert gas, the inert gas in the second inner cavity 301 will generate a third pressure on the needle valve assembly. Under the action of the third pressure, the outer needle valve 3 can be driven upward against the inner needle valve 2 and slide upward relative to the working cavity 11 together with the inner needle valve 2, so that the outer needle valve 3 is separated from the bottom end of the working cavity 11.

[0053] Reference Figures 4 to 6 As shown, when in the preparatory working condition before injecting the first fuel, the pressure in the adjustment chamber 201 is increased, that is, the value of the first pressure is increased, so that the first pressure is much greater than the sum of the forces of the second pressure and the third pressure. In this case, the inner needle valve 2 will slide downward to abut against the bottom end of the sleeve chamber 31 and drive the outer needle valve 3 to slide downward together to abut against the bottom end of the working chamber 11. In this case, the inner needle valve 2 blocks the first inner chamber 202 from the through hole 32, and the outer needle valve 3 blocks the second inner chamber 301 from the bottom of the working chamber 11, so that the first inner chamber 202 and the second inner chamber 301 are not connected to the first fuel injection hole 12. When the first fuel needs to be injected, the second through hole 102 is opened, so that the first fuel in the adjustment chamber 201 can be discharged through the second through hole 102, that is, the adjustment chamber 201 is quickly depressurized, so that the force driving the outer needle valve 3 to slide downward relative to the inner needle valve 2 in the second pressure so that the outer needle valve 3 abuts against the bottom end of the working chamber 11 is greater than the force driving the outer needle valve 3 upward against the inner needle valve 2 and the inner needle valve 2 slides upward relative to the working chamber 11 in the third pressure, thereby driving the outer needle valve 3 relative to the working chamber 11. On the basis of the inner needle valve 1 sliding downward and abutting against the bottom end of the working chamber 11, the inner needle valve 2 is further driven to slide upward relative to the outer needle valve 3, so that the double needle valve injector is in the first injection working state, that is, the outer needle valve 3 abuts against the bottom end of the working chamber 11 to block the communication between the second inner chamber 301 and the first fuel injection hole 12, and releases the abutment between the inner needle valve 2 and the outer needle valve 3, so that the first inner chamber 202 and the through hole 32 are connected with the first fuel injection hole 12, and then the first fuel in the first inner chamber 202 can be sprayed out from the first fuel injection hole 12 through the through hole.

[0054] In this embodiment, when the second fuel needs to be injected, the first fuel is filled into the adjustment chamber 201 and the first inner chamber 202 through the first fuel source 51, and the second through hole 102 is closed. At the same time, the second fuel is filled into the second inner chamber 301 through the fifth through hole 104 through the second fuel source 52.

[0055] When the adjustment chamber 201 and the first inner chamber 202 are respectively filled with the first fuel, the first fuel in the adjustment chamber 201 will still generate the first pressure on the inner needle valve 2, and the first fuel in the first inner chamber 202 will still generate the second upward pressure on the needle valve assembly. The first pressure and the second pressure are the same as the above content, and will not be repeated here.

[0056] When the second inner cavity 301 is filled with the second fuel, the second fuel in the second inner cavity 301 will generate a fourth pressure on the needle valve assembly. Under the effect of the fourth pressure, the outer needle valve 3 can be driven upward against the inner needle valve 2 and slide upward relative to the working cavity 11 together with the inner needle valve 2, so that the outer needle valve 3 is separated from the bottom end of the working cavity 11.

[0057] Reference Figure 4 , Figures 7 and 8 As shown, when in the preparatory working condition before injecting the second fuel, the value of the first pressure is increased so that the first pressure is much greater than the sum of the forces of the second pressure and the fourth pressure. In this case, the inner needle valve 2 will slide downward to abut against the bottom end of the sleeve cavity 31 and drive the outer needle valve 3 to slide downward together to abut against the bottom end of the working cavity 11. In this case, the first inner cavity and the second inner cavity are not connected to the first fuel injection hole. When it is necessary to inject the second fuel, the second through hole 102 is opened so that the first fuel in the adjustment cavity 201 can be discharged through the second through hole 102, that is, the adjustment cavity 201 is quickly depressurized, so that the value of the force in the fourth pressure that drives the outer needle valve 3 upward against the inner needle valve 2 and slides upward relative to the working cavity 11 together with the inner needle valve 2 is greater than the value of the force in the second pressure that drives the outer needle valve 3 to slide downward relative to the inner needle valve 2 so that the outer needle valve 3 abuts against the bottom end of the working cavity 11, thereby driving the outer needle valve 3 presses upward against the inner needle valve 2 and slides upward together with the inner needle valve 2 relative to the working chamber 11, so that the double needle valve injector is in the second injection working state, that is, the inner needle valve 2 presses against the bottom end of the sleeve chamber 31 and blocks the through hole 32 to block the communication between the first inner chamber 202 and the first fuel injection hole 12, and the outer needle valve 3 releases the contact with the working chamber 11 to make the second inner chamber 301 communicate with the first fuel injection hole 12, so that the second fuel in the second inner chamber 301 can be sprayed out through the first fuel injection hole 12.

[0058] The above process has a simple structure, and the operating condition switching is convenient and reliable. In addition to being injected through the first fuel injection hole 12, the first fuel and the second fuel each use a set of independent pipeline structures and fuel supply paths. The operating condition switching process does not require changing the oil circuit structure, which can effectively avoid the two fuels from mixing when switching the injection fuel, avoid affecting the fuel mixing ratio, ensure that the injection supply amount of the corresponding fuel is stable and reliable, and further ensure the reliable operation of the engine.

[0059] In addition, the time taken to switch from the first injection mode to the second injection mode is the time taken for the second fuel to replace the inert gas and fill the second inner cavity 301. When the second fuel source 52 and the reversing valve 54 are arranged in a reasonable position, this time is completely less than the injection interval required by the medium and low speed engines. Since the first fuel has been waiting in the first inner cavity 202, there is no need for the first fuel to be prepared for filling during the process. The inert gas pressure is much lower than the second fuel pressure. Through the matching optimization of the flow channel and the needle valve assembly, the time for the pressure reduction can be controlled to be below the injection interval required by the medium and low speed engines. Then the engine does not need to be shut down, and there is no need to wait for several injection cycles. During the continuous rotation of the engine crankshaft, the previous injection cycle runs in the old mode, and the next injection cycle can run in the new mode, so as to achieve seamless connection and fast switching.

[0060] Furthermore, in this embodiment, during the injection process of the first fuel, the second inner cavity 301 is always filled with inert gas. When the second fuel is not injected, the inert gas can be used to replace the second fuel in the second inner cavity 301, which can effectively dilute the concentration of the second fuel in the second inner cavity 301, thereby avoiding the second fuel from being retained in the second inner cavity 301 for a long time, thereby further avoiding the explosion hazard caused by the second fuel such as methanol, ammonia, dimethyl ether, etc. being retained in the second inner cavity 301 at high temperature and pressure for a long time, and further ensuring the safety of the entire engine system.

[0061] In this embodiment, the inert gas may be, but is not limited to, nitrogen.

[0062] In this embodiment, the main body 1 is formed by connecting components such as a spring seat, a gland, and a needle valve sleeve through a fixed connector.

[0063] The reversing valve 54 may be optionally but not limited to being an electromagnetic reversing valve.

[0064] In this embodiment, the second through hole 102 can be directly connected to the fuel tank 56 of the first fuel, and a switch valve 55 is also provided on the connecting pipeline between the second through hole 102 and the fuel tank 56. The switch valve 55 can realize the on-off control between the second through hole 102 and the fuel tank 56, which is equivalent to controlling the opening and closing of the second through hole 102.

[0065] The switch valve 55 can be optionally but not limited to being set as a solenoid valve.

[0066] In this embodiment, the switching control of the switching valve 54 and the opening and closing control of the switch valve 55 are both existing technologies and will not be described in detail here.

[0067] In addition, after the first fuel is filled into the first inner cavity 202 through the fourth through hole 103 and the third through hole 33, it can flow along the movement gap between the surface of the inner needle valve 2 and the cavity wall of the sleeve cavity 31 of the outer needle valve 3, which can effectively establish a relatively complete oil film, further ensuring the lubrication and sealing effect of the needle valve assembly. Figure 4 As shown, a lubrication hole 36 connected to the first inner cavity 202 is opened on the side wall of the outer needle valve 3. A portion of the first fuel can also flow through the lubrication hole 36 to between the side wall surface of the outer needle valve 3 and the cavity wall of the working cavity 11 to form an oil film, further ensuring the lubrication and sealing between the outer needle valve 3 and the working cavity 11.

[0068] Continue to refer to Figures 1 to 4 As shown, in actual use, with the long-term use of the double needle valve injector, the needle valve assembly will be aged, worn, etc., so that a part of the first fuel will exist in the oil film between the side wall surface of the outer needle valve 3 and the cavity wall of the working chamber 11, flowing downward along the gap between the side wall surface of the outer needle valve 3 and the cavity wall of the working chamber 11 and leaking into the second inner cavity 301. When the double needle valve injector is in the second injection condition, this part of the leaked first fuel will also be mixed with the second fuel and injected into the engine cylinder to participate in combustion, which will increase carbon emissions and worsen emission parameters such as nitrogen oxides and particulate matter. Even if the double needle valve injector is operated in the first injection condition for a long time, because the second inner cavity 301 is always inert gas, the inert gas pressure in the second inner cavity 301 is lower than the pressure of the first fuel in the first inner cavity 202, which will cause the first fuel in the first inner cavity 202 to leak to the second inner cavity 301 and gradually accumulate, and it may even be full in the long run. When the first injection condition is suddenly switched back to the second injection condition after a long period of time, the first few injection cycles all inject the first fuel with high calorific value and poor emissions. The first fuel is injected according to the designed injection amount of the second injection condition. The combustion work is obviously greater than the design value, and the engine speed increases rapidly, affecting the engine emissions and the speed regulation stability of the operating condition switching.

[0069] Therefore, in this embodiment, the main body 1 is further provided with a discharge hole 15 between the first inner cavity 202 and the second inner cavity 301, and the discharge hole 15 extends inwardly to the cavity wall of the working cavity 11, and the outer side of the discharge hole 15 is connected to the dirty oil separation box. Since the pressure at the discharge hole 15 is lower than the pressure in the first inner cavity 202, the first fuel with a higher pressure will flow along the gap between the side wall surface of the outer needle valve 3 and the cavity wall of the working cavity 11 to the discharge hole 15 to be discharged from the double needle valve injector and enter the oil-dirt separation box, so that the second inner cavity 301 is no longer mixed with the first fuel. After switching to the second injection mode, the first fuel no longer participates in combustion, thereby improving the engine's emissions and speed regulation stability after switching.

[0070] In this embodiment, continue to refer to Figures 1 to 4As shown, the side wall of the inner needle valve 2 extending into the sleeve cavity 31 has a molding groove 21, and the molding groove 21 and the sleeve cavity 31 together form the first inner cavity 202. Further, the groove wall of the molding groove 21 facing the cavity wall of the sleeve cavity 31 includes a first molding surface 211 and a second molding surface 212, the first molding surface 211 extends inwardly from the side wall surface of the inner needle valve 2 to the central axis direction of the inner needle valve 2, and the second molding surface 212 is arranged at the inclined end of the first molding surface 21 and extends along the central axis direction of the inner needle valve 2. In this embodiment, the molding groove 21 can provide sufficient accommodation space for the formation of the first inner cavity 202. The arrangement of the first molding surface 211 and the second molding surface 212 can provide reliable guidance for the first fuel entering the first inner cavity 202 through the fourth through hole 103 and the third through hole 33, so that the first fuel can be filled into the bottom end of the first inner cavity 202 more quickly and reliably, and pressure can be applied to the inner needle valve 2 and the outer needle valve 3 more quickly.

[0071] In this embodiment, continue to refer to Figures 1 to 4 As shown, the bottom end of the inner needle valve 2 is provided with a first conical abutting surface 22 along its own axial direction, and the first conical abutting surface 22 extends inwardly from the side wall surface of the inner needle valve 2 to the central axis direction of the inner needle valve 2. The bottom end of the sleeve cavity 31 is provided with a second conical abutting surface 34 along its own axial direction, and the second conical abutting surface 34 extends inwardly from the cavity wall of the sleeve cavity 31 to the central axis direction of the outer needle valve 3 to the port of the through hole 32; the inner needle valve 2 slides downward to make the first conical abutting surface 22 tightly abut against the second conical abutting surface 34 to block the through hole 32. In this embodiment, the setting of the first conical abutting surface 22 and the second conical abutting surface 34 can provide a more reliable and effective guide for the flow of the first fuel after the bottom of the inner needle valve 2 is released from the abutment with the bottom of the outer needle valve 3, so that the first fuel flows through the hole 32 faster and is sprayed out at the first injection hole 12.

[0072] More specifically, the working chamber 11 includes a first working chamber 111, a second working chamber 112 and a third working chamber 113 which are sequentially connected from top to bottom, wherein the upper end of the inner needle valve 2 can slide against the first working chamber 111 and form an adjustment chamber 201 together with the first working chamber 111, the outer needle valve 3 can slide against the second working chamber 112 and form a second inner chamber 301 together with the second working chamber 112, and the first oil injection hole 12 is opened on the third working chamber 113. The bottom end of the outer needle valve 3 is provided with a third conical abutting surface 35 along its own axial direction. The third conical abutting surface 35 extends inwardly from the side wall surface of the outer needle valve 3 to the central axis direction of the outer needle valve 3. The fourth conical abutting surface 14 is connected between the cavity wall of the second working chamber 112 and the cavity wall of the third working chamber 113. The inner needle valve 2 drives the outer needle valve 3 to slide downward together, so that the third conical abutting surface 35 can be tightly abutted against the fourth conical abutting surface 14 to block the communication between the second inner cavity 301 and the first injection hole 12. In this embodiment, the setting of the third conical abutting surface 35 and the fourth conical abutting surface 14 can provide a more reliable and effective guide for the flow of the second fuel after the bottom of the outer needle valve 3 is released from the abutment with the bottom of the working chamber 11, so that the second fuel can flow through the hole 32 faster and be sprayed out from the first injection hole 12.

[0073] In this embodiment, the second oil injection hole 13 is formed on the fourth conical abutting surface 14 , and the third conical abutting surface 35 is tightly abutted against the fourth conical abutting surface 14 to block the second oil injection hole 13 .

[0074] Specifically, when the first fuel is set to diesel and the second fuel is set to methanol or other fuels, the combustion heat generated by the same weight is less than half of that of diesel, and the density is even lower than that of diesel. In order to ensure that the dual-fuel engine has sufficient power performance when injecting the second fuel in the second injection condition, the injection volume of the second fuel such as methanol injected in the second injection condition of the same double needle valve injector must reach more than twice the volume of the first fuel such as diesel injected in the first injection condition within the same duration, which puts forward differentiated requirements for the injection flow rate under different injection conditions.

[0075] In this embodiment, refer to Figure 6 As shown in FIG. 1 , when the double needle valve injector is in the first injection state and injects the first fuel, the bottom end of the outer needle valve 3 is tightly against the second working chamber 112 and the third working chamber 113, that is, the third conical abutting surface 35 is tightly against the fourth conical abutting surface 14. At this time, the second fuel injection hole 13 is blocked, so that the first fuel in the first inner chamber 202 passes through the hole and is sprayed out from the first fuel injection hole 12. Figure 8As shown, when the double needle valve injector is in the second injection mode and injects the second fuel, the third conical abutting surface 35 releases the abutment with the fourth conical abutting surface 14, thereby releasing the blockage of the second fuel injection hole 13, so that the second fuel in the second inner cavity 301 can be injected through both the first fuel injection hole 12 and the second fuel injection hole 13 during the downward flow. In addition, in the process of switching from the first injection mode to the second injection mode, convenient and reliable switching of the injection amount is also achieved.

[0076] Continue to refer to Figures 1 to 4 As shown, the double needle valve injector further includes an elastic member 4, which is arranged in the working chamber 11 and sleeved on the inner needle valve 2. The inner needle valve 2 is provided with an abutment portion 23 protruding in the radial direction, and the upper end of the elastic member 4 abuts against the inner wall of the working chamber 11, and the lower end of the elastic member 4 abuts against the abutment portion 23. In this embodiment, the provision of the elastic member 4 can provide a buffer for the sliding of the inner needle valve 2, and can also provide a force to drive the inner needle valve 2 to reset.

[0077] The elastic member 4 is configured as a spring.

[0078] In this embodiment, the first through hole 101 includes a first hole portion 1011 , a second hole portion 1012 and a third hole portion 1013 which are connected in sequence, and the aperture of the second hole portion 1012 is smaller than the apertures of the first hole portion 1011 and the third hole portion 1013 .

[0079] In this embodiment, when the second through hole 102 changes from a closed state to an open state, the first fuel in the adjustment chamber 201 will be discharged through the second through hole 102, that is, the pressure in the adjustment chamber 201 is released. In this process, the first fuel source 51 will continue to supply the first fuel and fill it into the adjustment chamber 201 through the first through hole 101. By setting the first through hole as a first hole portion 1011, a second hole portion 1012 and a third hole portion 1013 that are sequentially connected, and the aperture of the second hole portion 1012 is smaller than the apertures of the first hole portion 1011 and the third hole portion 1013, after the first fuel filled in the adjustment chamber 201 is discharged, the size of the middle part of the first through hole 101, that is, the second hole portion 1012 is reduced, which effectively slows down the subsequent replenishment speed of the first fuel filling into the adjustment chamber 201 through the first through hole 101, and further ensures the pressure relief effect in the adjustment chamber 201.

[0080] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A double needle valve injector, characterized in that: include: The main body (1) has a working chamber (11), and a first oil injection hole (12) is opened at the bottom end of the working chamber (11); A needle valve assembly is arranged in the working chamber (11), the needle valve assembly comprising an inner needle valve (2) and an outer needle valve (3) slidably sleeved on the lower end of the inner needle valve (2); The upper end of the inner needle valve (2) can be slidably abutted against the working chamber (11) and together with the working chamber (11) form an adjustment chamber (201); the body (1) is respectively provided with a first through hole (101) and a second through hole (102) which are communicated with the adjustment chamber (201); the outer needle valve (3) has a sleeve chamber (31); the bottom end of the sleeve chamber (31) is provided with a through hole (32) which is communicated with the working chamber (11); the sleeve chamber (31) is communicated with the first oil injection hole (12) through the through hole (32); the outer needle valve (3) can be slidably sleeved on the lower end of the inner needle valve (2) through the sleeve chamber (31) and together with the inner needle valve (2) form an adjustment chamber (201); A first inner cavity (202) is formed, the first inner cavity (202) can be communicated with the first oil injection hole (12) through the through hole (32), the sleeve cavity (31) is provided with a third through hole (33) communicated with the first inner cavity (202), and the body (1) is provided with a fourth through hole (103) communicated with the third through hole (33); the outer needle valve (3) can be slidably abutted against the working cavity (11) and form a second inner cavity (301) together with the working cavity (11), the second inner cavity (301) can be communicated with the first oil injection hole (12), and the body (1) is provided with a fifth through hole (104) communicated with the second inner cavity (301); The double needle valve injector has a preparatory working condition, a first injection working condition and a second injection working condition; wherein, When in the preparatory working condition, the inner needle valve (2) is tightly against the bottom end of the sleeve cavity (31) and blocks the through hole (32), and the outer needle valve (3) is tightly against the bottom end of the working cavity (11) to block the communication between the second inner cavity (301) and the first oil injection hole (12); When in the first injection working condition, the inner needle valve (2) releases the contact with the sleeve cavity (31) to allow the first inner cavity (202), the through hole (32) and the first oil injection hole (12) to communicate, and the outer needle valve (3) abuts against the bottom end of the working cavity (11) to block the communication between the second inner cavity (301) and the first oil injection hole (12); When in the second injection working state, the inner needle valve (2) is tightly against the bottom end of the sleeve cavity (31) and blocks the through hole (32), and the outer needle valve (3) is released from the abutment with the working cavity (11) so that the second inner cavity (301) is connected with the first injection hole (12); A reversing valve (54) is provided on one side of the fifth through hole (104); the second fuel source (52) and the inert gas source (53) are respectively connected to two working oil ports of the reversing valve (54); and the fifth through hole (104) is connected to an oil outlet of the reversing valve (54); A first fuel source (51) is provided on one side of the first through hole (101), and the first fuel source (51) is connected to the first through hole (101) and the fourth through hole (103); A discharge hole (15) is also provided in the body (1) between the first inner cavity (202) and the second inner cavity (301), the discharge hole (15) extending inwardly to the cavity wall of the working cavity (11), and the outer side of the discharge hole (15) is connected to a dirty oil separation box.

2. The double needle valve injector according to claim 1, characterized in that: The side wall of the inner needle valve (2) extending into the sleeve cavity (31) has a molding groove (21), and the molding groove (21) and the sleeve cavity (31) together form the first inner cavity (202).

3. The double needle valve injector according to claim 2, characterized in that: The groove wall of the molding groove (21) facing the cavity wall of the sleeve cavity (31) comprises a first molding surface (211) and a second molding surface (212), wherein the first molding surface (211) extends inwardly from the side wall surface of the inner needle valve (2) in the direction of the central axis of the inner needle valve (2), and the second molding surface (212) is arranged at the inclined end of the first molding surface (211) and extends along the central axis of the inner needle valve (2).

4. The double needle valve injector according to claim 1, characterized in that: The bottom end of the inner needle valve (2) is provided with a first conical abutting surface (22) along its own axial direction, and the first conical abutting surface (22) extends inwardly from the side wall surface of the inner needle valve (2) in the direction of the central axis of the inner needle valve (2). The bottom end of the sleeve cavity (31) is provided with a second conical abutting surface (34) along its own axial direction, and the second conical abutting surface (34) extends inwardly from the cavity wall of the sleeve cavity (31) in the direction of the central axis of the outer needle valve (3) to the port of the through hole (32); the inner needle valve (2) slides downward so that the first conical abutting surface (22) is tightly abutted against the second conical abutting surface (34) to block the through hole (32).

5. The double needle valve injector according to claim 1, characterized in that: The working chamber (11) comprises a first working chamber (111), a second working chamber (112) and a third working chamber (113) which are connected in sequence from top to bottom; wherein the upper end of the inner needle valve (2) can be slidably abutted against the first working chamber (111) and together with the first working chamber (111) form the adjustment chamber (201); the outer needle valve (3) can be slidably abutted against the second working chamber (112) and together with the second working chamber (112) form the second inner chamber (301); and the first oil injection hole (12) is opened on the third working chamber (113).

6. The double needle valve injector according to claim 5, characterized in that: The bottom end of the outer needle valve (3) is provided with a third conical abutting surface (35) along its own axial direction, and the third conical abutting surface (35) extends inwardly from the side wall surface of the outer needle valve (3) toward the central axis direction of the outer needle valve (3). A fourth conical abutting surface (14) is connected between the cavity wall of the second working cavity (112) and the cavity wall of the third working cavity (113); the inner needle valve (2) drives the outer needle valve (3) to slide downward together, so that the third conical abutting surface (35) is tightly abutted against the fourth conical abutting surface (14), so as to block the connection between the second inner cavity (301) and the first oil injection hole (12).

7. The double needle valve injector according to claim 6, characterized in that: The fourth conical abutting surface (14) is provided with a second oil injection hole (13), and the third conical abutting surface (35) is tightly abutted against the fourth conical abutting surface (14) to block the second oil injection hole (13).

8. The double needle valve injector according to claim 1, characterized in that: It also includes an elastic member (4), which is arranged in the working chamber (11) and sleeved on the inner needle valve (2), and the inner needle valve (2) is provided with an abutment portion (23) protruding in the radial direction, the upper end of the elastic member (4) abuts against the inner wall of the working chamber (11), and the lower end of the elastic member (4) abuts against the abutment portion (23).

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