A dual fuel injector employing high pressure in-cylinder direct injection

Abstract

The application discloses a dual-fuel injector with high-pressure in-cylinder direct injection, which comprises an injector body, a first needle valve and a second needle valve; the inside of the injector body is provided with a first fuel cavity, a second fuel control oil cavity, a second fuel cavity, a second fuel control oil control cavity oil rail, a second fuel control oil storage cavity oil rail and a second fuel oil oil rail; a first fuel injection hole is formed in the bottom of the injector body, and a plurality of second fuel injection holes are arranged on the periphery of the first fuel injection hole; the second fuel control oil control cavity oil rail, the second fuel control oil storage cavity oil rail and the second fuel oil oil rail are connected and integrated together to control the second fuel injection; the first fuel cavity, the second fuel control oil cavity, the second fuel cavity, the first needle valve and the second needle valve are arranged in the space formed by the oil rail, low-carbon fuel and diesel can be simultaneously injected, and the space of the cylinder cover is saved.

Description

Technical Field

[0001] This invention relates to the field of dual-fuel injector technology, and more particularly to a dual-fuel injector employing high-pressure direct injection. Background Technology

[0002] Currently, the mainstream application of low-carbon fuel engine injectors is mostly low-pressure intake port injection. Under this condition, the injection pressure of the injector is relatively low, and the wear problem is not very serious. However, this low-pressure intake port injection scheme has low thermal efficiency and low-carbon fuel substitution rate, which cannot meet the requirements of future internal combustion engine applications. In order to further improve thermal efficiency and low-carbon fuel substitution rate, the technical route of in-cylinder diesel micro-injection igniting high-pressure direct injection of low-carbon fuel has been proposed, and the requirements for low-carbon fuel injectors have also increased from 5 bar for low-pressure intake port injection to tens of megapascals. Unlike high-carbon fuels such as diesel and gasoline, low-carbon fuels have low viscosity and poor lubrication characteristics. They cannot effectively lubricate the injection device while injecting fuel at high pressure, resulting in rapid wear and vapor cavitation problems of the control valve of electromagnetic injectors.

[0003] The above problems can be solved by introducing a high-pressure, low-carbon fuel injection device. Low-carbon and carbon-free fuels have poor compression ignition characteristics. When this part of the fuel is used in a compression ignition engine, it must be combined with diesel fuel. A small amount of diesel fuel is burned to ignite the low-carbon or carbon-free fuel with poor compression ignition characteristics. This means that two injectors need to be arranged on the engine cylinder head. Large-bore low-speed two-stroke diesel engines have large cylinder heads and can accommodate two injectors. However, for medium-speed engines with a cylinder diameter of only about 100mm, arranging two injectors in the cylinder head is subject to great space constraints. Summary of the Invention

[0004] This invention provides a dual-fuel injector that uses high-pressure direct injection, which can simultaneously install a low-carbon fuel injector and a diesel fuel injector on the cylinder head, saving cylinder head space.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A dual-fuel injector employing high-pressure in-cylinder direct injection includes an injector body, a first needle valve, and a second needle valve.

[0007] The injector body is provided with a first fuel chamber, a second fuel control oil chamber, a second fuel chamber, a second fuel control oil control chamber oil rail, a second fuel control oil accumulator chamber oil rail, and a second fuel oil rail. The bottom of the injector body is provided with a first fuel injection hole and a plurality of second fuel injection holes located around the first fuel injection hole.

[0008] The injector body is provided with the first needle valve, which is used to control the connection and disconnection between the first fuel injection hole and the first fuel chamber.

[0009] The second fuel chamber includes a second fuel channel and a plurality of second fuel chambers located at the lower end of the injector body, and the plurality of second fuel chambers are connected by the second fuel oil rail;

[0010] The injector body is provided with a plurality of second needle valves, which are used to control the connection and disconnection between the second fuel injection hole and the second fuel chamber;

[0011] The upper end of the injector body is provided with a second fuel control oil chamber for controlling the movement of the second needle valve. The second fuel control oil chamber includes a second fuel control oil control chamber and a second fuel control oil accumulator chamber. Multiple second fuel control oil control chambers are connected through the second fuel control oil control chamber oil rail, and multiple second fuel control oil accumulator chambers are connected through the second fuel control oil accumulator chamber oil rail.

[0012] The first fuel chamber, the second fuel control oil chamber, the second fuel chamber, the first needle valve, and the second needle valve are all disposed inside the space formed by the oil rail of the second fuel control oil control chamber, the oil rail of the second fuel control oil accumulator chamber, and the oil rail of the second fuel oil.

[0013] Furthermore, it also includes a first solenoid valve. The first fuel chamber includes a first fuel inlet port, a first fuel inlet channel, a first fuel accumulator chamber, a first fuel control chamber, a first low-pressure fuel chamber, and a first fuel return port. The first solenoid valve is located inside the first low-pressure fuel chamber. The first low-pressure fuel chamber is connected to the first fuel return port. The first fuel inlet port is connected to the first fuel inlet channel and the first fuel control chamber. The first fuel inlet channel is connected to the first fuel accumulator chamber. The lower part of the first needle valve is provided with a first needle valve control oil pressure acting cone surface. The top surface of the first needle valve is located in the first fuel control chamber. The first needle valve control oil pressure acting cone surface is located in the first fuel accumulator chamber. When the first solenoid valve is energized, the first low-pressure fuel chamber is connected to the first fuel control chamber. The control oil in the first fuel control chamber flows into the first low-pressure fuel chamber, driving the first needle valve to move upward.

[0014] Furthermore, the injector body includes a main body and a first fuel channel module, the first fuel channel module being fixedly connected to the lower side of the main body, and the connection between the main body and the first fuel channel module being provided with a first fuel control chamber.

[0015] Furthermore, it also includes a second solenoid valve. The second fuel control oil chamber further includes a second fuel control oil inlet, a second fuel control oil channel, and a second fuel control oil return port. The second solenoid valve is located on the outside of the injector body. The second fuel control oil inlet is connected to the oil rail of the second fuel control oil control chamber. One end of the second fuel control oil channel is connected to the oil rail of the second fuel control oil control chamber, and the other end of the second fuel control oil channel is connected to the oil rail of the second fuel control oil accumulator chamber. The second fuel control oil return port is connected to the oil rail of the second fuel control oil control chamber. The upper middle part of the second needle valve is provided with a second needle valve control oil pressure acting cone surface. The top surface of the second needle valve is located in the second fuel control oil control chamber. When the second solenoid valve is energized, the control oil in the second fuel control oil control chamber flows to the second fuel control oil return port, driving the second needle valve to move upward.

[0016] Furthermore, the injector body also includes a second fuel control module, a second fuel channel module, a second fuel accumulator module, and a second fuel injection module. The second fuel control module is fixedly connected to the lower side of the main body, the second fuel channel module is fixedly connected to the lower side of the second fuel control module, the second fuel control module and the second fuel channel module are fixedly connected to the outside of the first fuel channel module, the second fuel accumulator module is fixedly connected to the lower side of the second fuel channel module, and the second fuel injection module is fixedly connected to the lower side of the second fuel accumulator module. A second fuel control oil control chamber is provided at the connection between the main body and the second fuel control module, a second fuel control oil accumulator chamber is provided at the connection between the second fuel control module and the second fuel channel module, and a second fuel chamber is provided at the connection between the second fuel accumulator module and the second fuel injection module.

[0017] Furthermore, it also includes a sealing ring, which is located at the connection between the second fuel channel module and the second fuel accumulator module. The sealing ring is located on the outside of the second needle valve, and the second fuel chamber is a sealed chamber.

[0018] Furthermore, the top surface area of ​​the first needle valve is S1, and the area of ​​the cone surface acting on the control oil pressure of the first needle valve is S2, where S1 equals S2.

[0019] Furthermore, the top surface area of ​​the second needle valve is S3, and the area of ​​the cone surface acting on the control oil pressure of the second needle valve is S4, where S3 is greater than S4.

[0020] Furthermore, it also includes a needle valve spring, which is sleeved on the outer side of the top of the first needle valve and the outer side of the top of the second needle valve.

[0021] Beneficial effects: The dual-fuel injector with high-pressure in-cylinder direct injection disclosed in this application connects and integrates multiple chambers controlling the second fuel injection by setting up the second fuel control oil control chamber rail, the second fuel control oil accumulator rail, and the second fuel oil rail. The first fuel chamber, the second fuel control oil chamber, the second fuel chamber, the first needle valve, and the second needle valve are all located inside the space formed by the second fuel control oil control chamber rail, the second fuel control oil accumulator rail, and the second fuel oil rail. It can simultaneously inject low-carbon fuel and diesel, saving cylinder head space and providing more space for the arrangement of electronic control systems and other components. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a dual-fuel injector employing high-pressure in-cylinder direct injection disclosed in an embodiment of the present invention;

[0024] Figure 2 This is a front view of a dual-fuel injector employing high-pressure in-cylinder direct injection disclosed in an embodiment of the present invention;

[0025] Figure 3 This is a left view of a dual-fuel injector employing high-pressure in-cylinder direct injection disclosed in an embodiment of the present invention;

[0026] Figure 4 for Figure 2 Sectional view of AA;

[0027] Figure 5 for Figure 2 BB section view;

[0028] Figure 6 for Figure 3 CC section view;

[0029] Figure 7 for Figure 6 A magnified view of part A in the middle;

[0030] Figure 8 for Figure 6 A magnified view of part B in the middle section;

[0031] Figure 9 for Figure 3 DD section view;

[0032] Figure 10 for Figure 3 EE section view;

[0033] Figure 11 for Figure 3 FF section view;

[0034] In the diagram: 1. First solenoid valve; 2. Injector body; 21. Main body; 22. First fuel channel module; 23. Second fuel control module; 24. Second fuel channel module; 25. Second fuel accumulator module; 26. Second fuel injection module; 3. First fuel chamber; 31. First fuel inlet; 32. First fuel inlet channel; 33. First fuel accumulator chamber; 34. First fuel control chamber; 35. First low-pressure fuel chamber; 36. First fuel return port; 4. Needle valve spring; 5. First needle valve; 51. First needle valve assembly; 52. First needle valve control oil pressure action cone; 6. Second needle valve; 61. Second needle valve assembly; 62. Second needle valve control... 7. Oil pressure acting cone surface; 8. Sealing ring; 9. Second fuel control oil chamber; 10. Second fuel control oil inlet hole; 11. Second fuel control oil inlet node; 12. Second fuel control oil channel; 13. Second fuel control oil control chamber; 14. Second fuel control oil accumulator chamber; 15. Second fuel control oil return hole; 16. Second fuel control oil return node; 17. Second fuel chamber; 18. Second fuel channel; 19. Second fuel chamber; 10. Second fuel control oil control chamber oil rail; 11. Second fuel control oil accumulator chamber oil rail; 12. Second fuel oil rail; 13. Second solenoid valve; 14. First fuel injection hole; 15. Second fuel injection hole. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This embodiment provides a dual-fuel injector employing high-pressure in-cylinder direct injection, such as... Figure 1-11 As shown, it includes an injector body 2, a first needle valve 5, and a second needle valve 6;

[0037] The injector body 2 is provided with a first fuel chamber 3, a second fuel control oil chamber 8, a second fuel chamber 9, a second fuel control oil control chamber oil rail 10, a second fuel control oil accumulator chamber oil rail 11, and a second fuel oil rail 12. The bottom of the injector body 2 is provided with a first fuel injection hole 14 and a plurality of second fuel injection holes 15 located around the first fuel injection hole 14.

[0038] The injector body 2 is provided with the first needle valve 5, which is used to control the connection and disconnection between the first fuel injection hole 14 and the first fuel chamber 3.

[0039] The second fuel chamber 9 includes a second fuel passage 91 and a plurality of second fuel chambers 92 located at the lower end of the injector body 2. The plurality of second fuel chambers 92 are connected by the second fuel oil rail 12.

[0040] The injector body 2 is provided with a plurality of second needle valves 6, which are used to control the connection and disconnection between the second fuel injection hole 15 and the second fuel chamber 92.

[0041] The upper end of the injector body 2 is provided with a second fuel control oil chamber 8 for controlling the movement of the second needle valve 6. The second fuel control oil chamber 8 includes a second fuel control oil control chamber 83 and a second fuel control oil accumulator chamber 84. Multiple second fuel control oil control chambers 83 are connected through the second fuel control oil control chamber oil rail 10, and multiple second fuel control oil accumulator chambers 84 are connected through the second fuel control oil accumulator chamber oil rail 11.

[0042] The first fuel chamber 3, the second fuel control oil chamber 8, the second fuel chamber 9, the first needle valve 5 and the second needle valve 6 are all disposed inside the space formed by the oil rail 10 of the second fuel control oil control chamber, the oil rail 11 of the second fuel control oil accumulator chamber and the oil rail 12 of the second fuel oil.

[0043] In this embodiment, the first fuel chamber contains diesel fuel, the second fuel chamber contains low-carbon fuel, and the second fuel control oil chamber contains diesel fuel. The first needle valve controls the connection and disconnection between the first fuel injection orifice and the first fuel chamber, thereby controlling the injection of diesel fuel. The second fuel control oil chamber controls the movement of the second needle valve, thereby controlling the connection and disconnection between the second fuel injection orifice and the second fuel chamber, thereby controlling the injection of low-carbon fuel. The arrangement of the second fuel control oil control chamber rail, the second fuel control oil accumulator rail, and the second fuel oil rail connects and integrates multiple chambers controlling the second fuel injection. The first fuel chamber, the second fuel control oil chamber, the second fuel chamber, the first needle valve, and the second needle valve are all located inside the space formed by the second fuel control oil control chamber rail, the second fuel control oil accumulator rail, and the second fuel oil rail, which can simultaneously inject low-carbon fuel and diesel fuel, saving cylinder head space and providing more space for the arrangement of electronic control systems and other components.

[0044] Low-carbon fuels have a lower calorific value than high-carbon fuels. To ensure engine performance isn't reduced by switching to low-carbon fuels, the injection quality of low-carbon fuels must be greater than that of high-carbon fuels. Increasing injection pressure and pulse width can improve fuel injection quality; however, excessively increasing injection pressure will shorten injector life and reduce reliability, while excessively increasing injection pulse width will disrupt the engine's operating cycle. Therefore, introducing multiple low-carbon fuel injectors can increase fuel injection quality without significantly increasing injection pressure and pulse width.

[0045] In a specific embodiment, a first solenoid valve 1 is also included. The first fuel chamber 3 includes a first fuel inlet 31, a first fuel inlet channel 32, a first fuel accumulator 33, a first fuel control chamber 34, a first low-pressure fuel chamber 35, and a first fuel return port 36. The first solenoid valve 1 is disposed inside the first low-pressure fuel chamber 35. The first low-pressure fuel chamber 35 is connected to the first fuel return port 36. The first fuel inlet 31 is connected to the first fuel inlet channel 32 and the first fuel control chamber 34. The first fuel inlet channel 32 is connected to... The first fuel accumulator chamber 33 is connected. The lower part of the first needle valve 5 is provided with a first needle valve control oil pressure acting cone surface 52. The top surface of the first needle valve 5 is located in the first fuel control chamber 34. The first needle valve control oil pressure acting cone surface 52 is located in the first fuel accumulator chamber 33. When the first solenoid valve 1 is energized, the first fuel low-pressure chamber 35 is connected to the first fuel control chamber 34. The control oil in the first fuel control chamber 34 flows into the first fuel low-pressure chamber 35. The bottom of the first needle valve 5 is provided with a first needle valve assembly 51, which drives the... When the first needle valve assembly 51 moves upward, and the first solenoid valve electromagnet is not energized, the preload of the first solenoid valve spring presses against the first solenoid valve body. The bottom of the first solenoid valve body abuts against the inner wall of the first low-pressure fuel chamber, and the first solenoid valve needle blocks the bottom of the first low-pressure fuel chamber, so that the first low-pressure fuel chamber and the first fuel control chamber are not connected. The first fuel enters the first fuel accumulator chamber through the first fuel inlet hole and the first fuel inlet channel. At this time, the first needle valve assembly at the bottom of the first needle valve is pressed tightly against the needle valve seat, blocking the first fuel injection hole, and diesel fuel is not injected. When the first solenoid valve electromagnet is energized, it generates magnetic force. When the electromagnetic force is greater than the spring force of the first solenoid valve, the valve body of the first solenoid valve moves upward under the action of the resultant force. The valve needle of the first solenoid valve disengages from the bottom opening of the first low-pressure fuel chamber, and the first low-pressure fuel chamber and the first fuel control chamber are connected. The high-pressure control oil in the first fuel control chamber leaks into the first low-pressure fuel chamber and returns to the fuel tank through the first fuel return port. At this time, the control oil pressure in the first fuel control chamber decreases, the first needle valve rises, and the first fuel accumulator chamber is connected to the first fuel injection port. Diesel fuel is injected through the first fuel injection port.

[0046] In a specific embodiment, the injector body 2 includes a main body 21 and a first fuel channel module 22. The top and bottom of the main body 21 are provided with threaded structures for connection. The main body 21 is provided with a first fuel inlet hole 31, a first fuel inlet channel 32, a first fuel low-pressure chamber 35, a first fuel return hole 36, a second fuel control oil inlet hole 81, a second fuel control oil return hole 85, and a second fuel channel 91. The first fuel channel module 22 is fixedly connected to the lower side of the main body 21. The top and bottom of the first fuel channel module 22 are provided with threaded structures for connection. The first fuel channel module 22 is provided with a first fuel inlet channel 32 and a first needle valve 5. The connection between the main body 21 and the first fuel channel module 22 is provided with a first fuel control chamber 34. The modular design of the injector body facilitates the machining of the internal cavities.

[0047] In a specific embodiment, a second solenoid valve 13 is also included. The second fuel control oil chamber 8 further includes a second fuel control oil inlet 81, a second fuel control oil channel 82, and a second fuel control oil return port 85. The second fuel control oil inlet 81 includes a second fuel control oil inlet node 811, and the second fuel control oil return port 85 includes a second fuel control oil return node 851. The second solenoid valve 13 is located outside the injector body 2. The second fuel control oil inlet node 811 is connected to the oil rail 10 of the second fuel control oil control chamber. One end of the second fuel control oil channel 82 is connected to the oil rail 10 of the second fuel control oil control chamber. The other end of the second fuel control oil passage 82 is connected to the oil rail 11 of the second fuel control oil accumulator chamber. The second fuel control oil return node 851 is connected to the oil rail 10 of the second fuel control oil control chamber. The upper middle part of the second needle valve 6 is provided with a second needle valve control oil pressure acting cone surface 62. The top surface of the second needle valve 6 is located in the second fuel control oil control chamber 83. The second needle valve control oil pressure acting cone surface 62 is located in the second fuel control oil accumulator chamber 84. When the second solenoid valve 13 is energized, the control oil in the second fuel control oil control chamber 83 flows to the second fuel control oil return hole 85. The bottom of the second needle valve 6 is provided with a second needle valve coupler. The assembly 61 drives the second needle valve assembly 61 to move upward. The second fuel control oil enters the oil rail of the second fuel control oil control chamber through the second fuel control oil inlet hole and the second fuel control oil inlet node, and then enters the second fuel control oil control chamber. The second fuel control oil channel is a channel connecting the oil rail of the second fuel control oil control chamber and the oil rail of the second fuel control oil accumulator chamber. The second fuel control oil enters the oil rail of the second fuel control oil accumulator chamber through the second fuel control oil channel, and then enters the second fuel control oil accumulator chamber through the oil rail of the second fuel control oil accumulator chamber. When the second solenoid valve is not energized, the downward pressure of the second fuel control oil control chamber on the second needle valve is greater than the second fuel control oil accumulator pressure. The upward pressure of the second needle valve in the second fuel chamber causes the second needle valve assembly to press tightly against the needle valve seat, blocking the second fuel injection orifice. Low-carbon fuel enters the second fuel chamber through the second fuel passage, at which point low-carbon fuel is not injected. When the second solenoid valve is energized, the control oil in the second fuel control oil control chamber enters the second fuel control oil return orifice through the second fuel control oil return node located on the oil rail of the second fuel control oil control chamber, and flows back to the fuel tank through the second solenoid valve. At this time, the upward pressure of the second fuel accumulator chamber on the second needle valve stem is greater than the downward pressure of the second fuel control oil control chamber on the second needle valve stem. At this time, the second needle valve lifts, and the second fuel chamber connects with the second fuel injection orifice, allowing low-carbon fuel to be injected.

[0048] In a specific embodiment, the injector body 2 further includes a second fuel control module 23, a second fuel channel module 24, a second fuel accumulator module 25, and a second fuel injection module 26. The second fuel control module 23 has a cylindrical structure, and its top and bottom are provided with threaded structures for connection. The second fuel control module 23 contains a second needle valve 6, a second fuel control oil channel 82, a second fuel channel 91, and a second fuel control oil control chamber rail 10. The second fuel channel module 24 has a cylindrical structure, and its top and bottom are provided with threaded structures for connection. The second fuel channel module 24 contains a second needle valve 6, a second fuel channel 91, and a second fuel control oil accumulator chamber rail 11. The second fuel accumulator module 25 has a cylindrical structure, and its top and bottom are provided with threaded structures for connection. The second fuel accumulator module 25 contains a second needle valve assembly 61, a second fuel channel 91, and a second fuel oil rail 12. The second fuel injection module... The top and bottom of the second fuel injection module 26 are provided with threaded structures for connection. The second needle valve assembly 61 is provided inside the second fuel injection module 26. The second fuel control module 23 is fixedly connected to the lower side of the main body 21. The second fuel channel module 24 is fixedly connected to the lower side of the second fuel control module 23. The second fuel control module 23 and the second fuel channel module 24 are fixedly connected to the outside of the first fuel channel module 22. The second fuel accumulator module 25 is fixedly connected to the lower side of the second fuel channel module 24. The second fuel injection module is fixedly connected to the lower side of the second fuel accumulator module 25. The connection between the main body 21 and the second fuel control module 23 is provided with a second fuel control oil control chamber 83. The connection between the second fuel control module 23 and the second fuel channel module 24 is provided with a second fuel control oil accumulator chamber 84. The connection between the second fuel accumulator module 25 and the second fuel injection module 26 is provided with a second fuel chamber 92. The modular design of the injector body facilitates the machining of the internal cavities.

[0049] In a specific embodiment, a sealing ring 7 is also included. The sealing ring 7 is located at the connection between the second fuel channel module 24 and the second fuel accumulator module 25. The sealing ring 7 is located on the outside of the second needle valve 6. The second fuel chamber 9 is a sealed chamber. Because low-carbon fuel has low viscosity and poor lubrication characteristics, it is easy to cause rapid wear of the control valve of the electromagnetic injector. The sealing ring and the low-carbon fuel sealed chamber isolate the control valve of the electromagnetic injector from the low-viscosity, poorly lubricated low-carbon fuel, thereby preventing low-carbon fuel leakage and preventing low-carbon fuel from entering the electromagnetic control valve and causing rapid wear of the injector.

[0050] In a specific embodiment, the top surface area of ​​the first needle valve 5 is S1, and the area of ​​the first needle valve control oil pressure acting cone surface 52 is S2. S1 equals S2. The first fuel enters the first fuel accumulator chamber through the first fuel inlet hole and the first fuel inlet channel. The first fuel inlet hole and the first fuel control chamber are connected. At this time, the pressure in the first fuel control chamber and the first fuel accumulator chamber are equal, and S1 equals S2. Therefore, the pressure F1 acting on the top surface of the first needle valve is equal to the pressure F2 acting on the first needle valve control oil pressure acting cone surface. When the electromagnet is not energized, the first needle valve is pressed tightly at the first fuel injection hole under the pre-pressure of the needle valve spring. When the electromagnet is energized, the diesel fuel in the first fuel control chamber is discharged through the first fuel return chamber, and the pressure in the first fuel control chamber decreases. The pressure F1 acting on the top surface of the first needle valve is much smaller than the pressure F2 acting on the first needle valve control oil pressure acting cone surface. The first needle valve overcomes the remaining pressure in the first fuel control chamber and the pre-pressure of the needle valve spring and rises upward, and the diesel fuel is injected through the injection hole.

[0051] In a specific embodiment, the top surface area of ​​the second needle valve 6 is S3, and the area of ​​the control oil pressure acting cone surface 62 of the second needle valve is S4. S3 is greater than S4. The second fuel control oil enters the second fuel control oil control chamber and the second fuel control oil accumulator chamber through the second fuel control oil inlet hole, the second fuel control oil channel, the second fuel control oil control chamber rail, and the second fuel control oil accumulator chamber rail. At this time, the pressure in the second fuel control oil control chamber and the second fuel control oil accumulator chamber is equal, and S3 is greater than S4. Therefore, the pressure F3 acting on the top surface of the second needle valve is greater than the pressure F4 acting on the control oil pressure acting cone surface of the second needle valve. Under the action of the preload of the needle valve spring and the pressure difference, the second needle valve is pressed tightly at the second fuel injection hole. When the second solenoid valve is energized... The control oil in the second fuel control oil control chamber is discharged through the second fuel control oil return node on the second fuel control oil control chamber oil rail. At this time, the pressure in the second fuel control oil accumulator chamber is greater than the pressure in the second fuel control oil control chamber. The pressure F4 acting on the control oil pressure cone of the second needle valve is greater than the resultant force of the force F3 acting on the top surface of the second needle valve and the needle valve spring. At this time, the needle valve lifts up, and low-carbon fuel is injected. When the second solenoid valve is de-energized, the pressure in the second fuel control oil control chamber and the second fuel control oil accumulator chamber recovers. The needle valve needs to overcome the pressure F5 acting on the lower surface of the second needle valve to sit down. The sum of the pressure of the second needle valve spring and F3 is greater than the sum of F4 and F5. At this time, the resultant force on the second needle valve is downward, the second needle valve sits down, and the second fuel injection stops.

[0052] In a specific embodiment, a needle valve spring 4 is also included. The needle valve spring 4 is sleeved on the outer side of the top of the first needle valve 5 and the outer side of the top of the second needle valve 6. The needle valve spring provides pre-pressure to the needle valve to ensure the stability of the needle valve during operation.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-fuel injector employing high-pressure in-cylinder direct injection, characterized in that: Includes injector body (2), first needle valve (5) and second needle valve (6); The injector body (2) is provided with a first fuel chamber (3), a second fuel control oil chamber (8), a second fuel chamber (9), a second fuel control oil control chamber oil rail (10), a second fuel control oil accumulator chamber oil rail (11), and a second fuel oil rail (12). The bottom of the injector body (2) is provided with a first fuel injection hole (14) and a plurality of second fuel injection holes (15) located on the outer periphery of the first fuel injection hole (14). The injector body (2) is provided with the first needle valve (5), which is used to control the connection and disconnection between the first fuel injection hole (14) and the first fuel chamber (3). The second fuel chamber (9) includes a second fuel passage (91) and a plurality of second fuel chambers (92) located at the lower end of the injector body (2). The plurality of second fuel chambers (92) are connected by the second fuel oil rail (12). The injector body (2) is provided with a plurality of second needle valves (6), which are used to control the connection and disconnection between the second fuel injection hole (15) and the second fuel chamber (92); The upper end of the injector body (2) is provided with a second fuel control oil chamber (8) for controlling the movement of the second needle valve (6). The second fuel control oil chamber (8) includes a second fuel control oil control chamber (83) and a second fuel control oil accumulator chamber (84). Multiple second fuel control oil control chambers (83) are connected through the second fuel control oil control chamber oil rail (10), and multiple second fuel control oil accumulator chambers (84) are connected through the second fuel control oil accumulator chamber oil rail (11). The first fuel chamber (3), the second fuel control oil chamber (8), the second fuel chamber (9), the first needle valve (5) and the second needle valve (6) are all located inside the space formed by the oil rail (10) of the second fuel control oil control chamber, the oil rail (11) of the second fuel control oil accumulator chamber and the oil rail (12) of the second fuel oil. The injector body (2) includes a main body (21) and a first fuel channel module (22). The first fuel channel module (22) is fixedly connected to the lower side of the main body (21). A first fuel control chamber (34) is provided at the connection between the main body (21) and the first fuel channel module (22). The injector body (2) further includes a second fuel control module (23), a second fuel channel module (24), a second fuel accumulator module (25), and a second fuel injection module (26). The second fuel control module (23) is fixedly connected to the lower side of the main body (21), the second fuel channel module (24) is fixedly connected to the lower side of the second fuel control module (23), the second fuel control module (23) and the second fuel channel module (24) are fixedly connected to the outside of the first fuel channel module (22), and the second fuel accumulator module (25) is fixedly connected to... On the lower side of the second fuel channel module (24), the second fuel injection module (26) is fixedly connected to the lower side of the second fuel accumulator module (25). The connection between the main body (21) and the second fuel control module (23) is provided with the second fuel control oil control chamber (83). The connection between the second fuel control module (23) and the second fuel channel module (24) is provided with the second fuel control oil accumulator chamber (84). The connection between the second fuel accumulator module (25) and the second fuel injection module (26) is provided with the second fuel chamber (92). It also includes a sealing ring (7), which is located at the connection between the second fuel channel module (24) and the second fuel accumulator module (25). The sealing ring (7) is located on the outside of the second needle valve (6), and the second fuel chamber (9) is a sealed chamber.

2. A dual-fuel injector employing high-pressure in-cylinder direct injection as described in claim 1, characterized in that: It also includes a first solenoid valve (1). The first fuel chamber (3) includes a first fuel inlet port (31), a first fuel inlet channel (32), a first fuel accumulator chamber (33), a first fuel control chamber (34), a first low-pressure fuel chamber (35), and a first fuel return port (36). The first solenoid valve (1) is located inside the first low-pressure fuel chamber (35). The first low-pressure fuel chamber (35) is connected to the first fuel return port (36). The first fuel inlet port (31) is connected to the first fuel inlet channel (32) and the first fuel control chamber (34). The first fuel inlet channel (33) is connected to the first fuel return port (36). 32) Connected to the first fuel accumulator chamber (33), the lower part of the first needle valve (5) is provided with a first needle valve control oil pressure action cone surface (52), the top surface of the first needle valve (5) is located in the first fuel control chamber (34), and the first needle valve control oil pressure action cone surface (52) is located in the first fuel accumulator chamber (33). When the first solenoid valve (1) is energized, the first fuel low pressure chamber (35) is connected to the first fuel control chamber (34), and the control oil in the first fuel control chamber (34) flows to the first fuel low pressure chamber (35), driving the first needle valve (5) to move upward.

3. A dual-fuel injector employing high-pressure in-cylinder direct injection as described in claim 1, characterized in that: It also includes a second solenoid valve (13). The second fuel control oil chamber (8) further includes a second fuel control oil inlet (81), a second fuel control oil passage (82), and a second fuel control oil return hole (85). The second solenoid valve (13) is located outside the injector body (2). The second fuel control oil inlet (81) is connected to the oil rail (10) of the second fuel control oil control chamber. One end of the second fuel control oil passage (82) is connected to the oil rail (10) of the second fuel control oil control chamber, and the other end of the second fuel control oil passage (82) is connected to the oil rail (11) of the second fuel control oil accumulator chamber. The second fuel control oil return hole (85) is connected to the oil rail (10) of the second fuel control oil control chamber. The upper middle part of the second needle valve (6) is provided with the second needle valve control oil pressure action cone surface (62). The top surface of the second needle valve (6) is located in the second fuel control oil control chamber (83). The second needle valve control oil pressure action cone surface (62) is located in the second fuel control oil accumulator chamber (84). When the second solenoid valve (13) is energized, the control oil in the second fuel control oil control chamber (83) flows to the second fuel control oil return hole (85), driving the second needle valve (6) to move upward.

4. A dual-fuel injector employing high-pressure in-cylinder direct injection according to claim 2, characterized in that: The top surface area of ​​the first needle valve (5) is S1, and the area of ​​the cone surface (52) acting on the control oil pressure of the first needle valve is S2. S1 equals S2.

5. A dual-fuel injector employing high-pressure in-cylinder direct injection according to claim 3, characterized in that: The top surface area of ​​the second needle valve (6) is S3, and the area of ​​the cone surface (62) acting on the control oil pressure of the second needle valve is S4, where S3 is greater than S4.

6. A dual-fuel injector employing high-pressure in-cylinder direct injection according to claim 1, characterized in that: It also includes a needle valve spring (4), which is sleeved on the outer side of the top of the first needle valve (5) and the outer side of the top of the second needle valve (6).

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