Dual-fuel injector and internal combustion engine

Abstract

The invention belongs to the technical field of injector manufacturing, and discloses a dual-fuel injector and an internal combustion engine. The fuel injection device comprises an injection main body part and an injection control part, the injection control part is installed at one end of the injection main body part, a fuel injection opening is formed in the other end of the injection main body part, a needle valve is slidably installed on the injection main body part, and the side, close to the fuel injection opening, of the needle valve is slidably sleeved with a valve body; an oil storage cavity is defined between the needle valve and the valve body, and in the open state of the dual-fuel injector, the first oil inlet channel communicates with the fuel oil injection opening through the oil storage cavity, the oil inlet communicates with the first oil inlet channel, and the gas inlet communicates with the fuel gas injection opening through the gas storage cavity; the problem that in the prior art, when an ejector ejects fuel gas, part of fuel oil leaks out, or the fuel oil in the high-pressure state reversely leaks to a gas inlet and a gas source, and consequently an engine cannot work normally is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of injector manufacturing, and in particular to a dual-fuel injector and an internal combustion engine. Background Art

[0002] In the commercial vehicle sector, the engine, as the vehicle's core power unit, directly determines its commercial value and market competitiveness through its performance and operating costs. Traditional engines rely on a single fossil fuel, converting the fuel's chemical energy into the mechanical kinetic energy required to propel the vehicle through internal combustion. However, global energy market volatility and increasingly stringent environmental regulations continue to drive vehicle fuel costs, making reducing long-term operating costs a key concern for both manufacturers and end-users. To effectively address this challenge, significantly reduce energy consumption costs throughout the commercial vehicle lifecycle, and improve its economic efficiency, a key technological development focus is on diversifying and flexibly managing engine fuel supply systems. Currently, a widely adopted and intensively developed solution is the dual-fuel system, combining oil and gas. This innovative design enables a single engine platform to operate in two distinct fuel modes, either in conjunction or in a switchable manner. Specifically, this system allows the engine to intelligently select or blend traditional liquid fuels (such as diesel) and gaseous fuels (such as natural gas or liquefied petroleum gas) based on real-time fuel availability, market prices, and operating conditions. Through a sophisticated electronic control unit and optimized fuel injection strategy, the engine is able to maintain an efficient and stable combustion process in both fuel modes, ensuring reliable and smooth power output. The core advantage of this dual-fuel operating mode is that it gives vehicle operators greater autonomy in fuel selection, allowing them to fully utilize the cost differences between different fuels and proactively avoid the risk of drastic price fluctuations of a single energy source, thereby fundamentally reducing energy consumption costs per mile. Therefore, developing and optimizing engines and their control systems that can efficiently, reliably, and seamlessly switch between oil and gas modes has become a key path and urgent need for continuous innovation in commercial vehicle power technology, reducing user costs, and enhancing the overall competitiveness of products.

[0003] The above-mentioned engine needs to use a dual-fuel injector for injection, which requires the injector to control the gas and fuel injection respectively. During the operation of the injector, the fuel pressure injected by the injector is relatively high. Usually, the needle valve inside the injector and the valve body outside the needle valve form an oil storage space, and the oil storage space is supplied with oil through the oil pipeline. The oil storage space sprays oil to the outside under the control of the solenoid valve, and the gas storage space is usually located between the valve body and the parts outside the valve body. However, the oil pipeline needs to pass through the parts outside the valve body and the valve body in turn to enter the oil storage space. There will be an assembly gap between the internal parts of the injector, and the distance between the oil pipeline and the gas storage space is relatively close. The fuel with its own high pressure will directly enter the gas storage space along the assembly gap, and it will also cause the high-pressure fuel to rush back to the air intake and the air source, resulting in fuel being sprayed out in the process of the injector injecting gas, which in turn causes the injection amount of the injector to be inaccurate, resulting in the engine not being able to work normally. Summary of the Invention

[0004] The purpose of the present invention is to provide a dual-fuel injector and an internal combustion engine to solve the problem in the prior art that when the injector injects gas, some fuel will leak out, or the high-pressure fuel will flow back to the air intake and the gas source, causing the engine to not work properly.

[0005] To achieve this object, the present invention adopts the following technical solution: The present invention provides a dual-fuel injector, comprising an injection main body and an injection control part, wherein the injection control part is mounted on one end of the injection main body and a gas injection port is formed on the other end thereof, a needle valve is slidably mounted on the injection main body, a valve body is slidably sleeved on the side of the needle valve close to the gas injection port, a fuel injection port is formed at the end of the valve body, a first oil inlet passage is formed in the needle valve along the axial direction, an oil storage chamber is formed between the needle valve and the valve body, when the needle valve is opened, the first oil inlet passage is connected to the fuel injection port through the oil storage chamber, an oil inlet is formed on the side of the injection main body close to the injection control part, the oil inlet is connected to the first oil inlet passage, an air storage chamber is formed between the injection main body and the valve body, when the valve body is lifted, an air inlet is formed on the injection main body, the air inlet is connected to the gas injection port through the air storage chamber, and the injection control part can control the opening and closing of the fuel injection port and the gas injection port.

[0006] Preferably, an oil return port is provided on the injection main body, a first oil return pipeline is provided inside the needle valve, the oil return port is connected to the first oil return pipeline, an oil return groove is provided on the outer wall of the needle valve, the first oil return pipeline is connected to the oil return groove.

[0007] Preferably, an opening is formed on the lower side of the injection main body, a section of the valve body is inserted into the opening, the fuel injection port is provided on the area of the valve body exposed outside the opening, the needle valve abuts against the inner wall of the valve body, and the valve body cover is connected to the gas injection port.

[0008] Preferably, the valve body forms an occasional fit with the injection main body, the annular cavity surrounded by the valve body and the injection main body is connected to the air storage cavity, and the installation cavity on the upper side of the valve body is installed with a first spring, and the other side of the first spring abuts against the boss on the inner side of the injection main body.

[0009] Preferably, the injection control unit includes a first inner cavity and an oil control port, the first inner cavity is installed with an oil control plate, the oil control plate is provided with a first pressure relief hole, an oil control valve is installed on the lower side of the oil control plate, and an oil control solenoid controls the movement of the oil control valve, the first inner cavity is connected to the installation cavity through a first connecting pipe, and the oil control port is connected to the first pressure relief hole.

[0010] Preferably, a second oil return pipe is opened on the side wall of the first inner cavity, and the second oil return pipe is connected to the oil return port.

[0011] Preferably, the injection control unit includes a second inner cavity, an oil injection plate is installed in the second inner cavity, a second pressure relief hole is provided on the oil injection plate, an oil injection valve is installed on the upper side of the oil injection plate, an oil injection solenoid controls the movement of the oil injection valve, the lower side of the oil injection plate is connected to the upper side of the needle valve to form a flow cavity, the oil inlet is connected to the flow cavity, and the flow cavity is connected to the second pressure relief hole.

[0012] Preferably, a third oil return pipe is provided on the inner wall of the upper side of the oil spray plate, and the third oil return pipe is connected to the oil return port.

[0013] Preferably, a protrusion is formed on the middle section of the needle valve, a second spring is installed on the upper side of the protrusion, and the second spring abuts against the inner wall of the injection main body.

[0014] An internal combustion engine comprises a combustion chamber and the dual-fuel injector described above, wherein the fuel injection port and the gas injection port are selectively connected to the combustion chamber.

[0015] Beneficial effect: By changing the position of the first oil inlet channel, the first oil inlet channel is made to flow along the inside of the needle valve, avoiding opening the first oil inlet channel near the air storage chamber, so that the positions of the first oil inlet channel and the oil inlet port are increased with the position of the air storage chamber, reducing the degree of oil leakage from the gap between the valve body and the injection main body to the air storage chamber, and at the same time, the pressure in the air storage chamber can be stabilized, and the pressure fluctuation of the injection control chamber can be stabilized and the fluctuation amplitude can be reduced, so that the injection of the dual-fuel injector is more accurate, and the engine can then work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a cross-sectional view of a dual fuel injector of the present invention;

[0017] Figure 2 is an enlarged cross-sectional view of the injection control portion of the present invention;

[0018] Figure 3 This is an enlarged cross-sectional view of the gas injection port of the present invention;

[0019] Figure 4 It is an enlarged cross-sectional view of the oil return groove of the present invention.

[0020] In the figure: 1. injection main body; 2. injection control part; 3. gas injection port; 4. fuel injection port; 5. needle valve; 6. valve body; 7. first oil inlet channel; 8. oil storage chamber; 9. oil inlet; 10. air storage chamber; 11. air inlet; 12. oil return port; 13. first oil return pipeline; 14. oil return groove; 15. first spring; 16. first inner cavity; 17. oil control port; 18. oil control plate; 19. first pressure relief hole; 20. oil control valve; 21. oil control electromagnet; 22. second oil return pipe; 23. second inner cavity; 24. oil injection plate; 25. second pressure relief hole; 26. oil injection valve; 27. oil injection electromagnet; 28. third oil return pipe; 29. second spring. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0022] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0023] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0024] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0025] In commercial vehicle dual-fuel engines, dual-fuel injectors must independently control fuel and gas injection. High-pressure fuel is stored in a reservoir enclosed by an internal needle valve and an outer valve body. This fuel is supplied via a fuel line and ejected under solenoid control. The gas reservoir is typically located between the valve body and its surrounding components. A key challenge is that to supply the fuel reservoir, the fuel line must pass through the valve body's surrounding components and then the valve body itself. Due to the inevitable assembly gaps between the injector's internal components and the proximity of the fuel line to the gas reservoir, high-pressure fuel can easily leak through these tiny gaps during delivery, directly into the gas reservoir. Consequently, when the engine is operating in gas injection mode, the injector, which should only be injecting gas, will also inject fuel. This unintended fuel mixing severely disrupts the precise metering of gas injection, causing uncontrolled injection volume and ultimately disrupting the engine's normal combustion process and operating conditions.

[0026] In order to solve the above problems, Figures 1 to 4As shown, the present invention provides a dual-fuel injector, which includes an injection main body 1 and an injection control part 2. The injection control part 2 is installed on one end of the injection main body 1, and a gas injection port 3 is provided at the other end. A needle valve 5 is slidably installed on the injection main body 1. The needle valve 5 is slidably sleeved with a valve body 6 on the side close to the gas injection port 3. A fuel injection port 4 is provided at the end of the valve body 6. A first oil inlet channel 7 is provided in the needle valve 5 along the axial direction. An oil storage chamber 8 is formed between the needle valve 5 and the valve body 6. When the needle valve 5 is in an open state and raised, the first oil inlet channel 7 is connected to the fuel injection port 4 through the oil storage chamber 8. An oil inlet 9 is provided on the side of the injection main body 1 close to the injection control part 2. The oil inlet 9 is connected to the first oil inlet channel 7. The injection main body 1 and the valve body 6 form an air storage chamber 10. An air inlet 11 is provided on the injection main body 1. When the valve body 6 is in an open state and raised, the air inlet 11 is connected to the gas injection port 3 through the air storage chamber 10. The injection control part 2 can control the opening and closing of the fuel injection port 4 and the gas injection port 3.

[0027] When the needle valve 5 slides downward and abuts against the valve body 6, the fuel injection port 4 can be closed. When the valve body 6 slides downward and abuts against the inclined surface on the inner side of the injection main body 1, the gas injection port 3 can be closed. Through the up and down movement of the valve body 6 and the needle valve 5, the opening and closing of the fuel injection port 4 and the gas injection port 3 can be flexibly controlled. In order to prevent the gas storage chamber 10 from being invaded by fuel, the first oil inlet channel 7 and the oil inlet port 9 are opened at a position away from the gas storage chamber 10, and the first oil inlet channel 7 is opened inside the needle valve 5. The high-pressure oil entering the oil inlet port 9 enters the needle valve 5 from the top of the needle valve 5. The high-pressure oil entering the dual-fuel injector will be blocked from diffusing into the gas storage chamber 10 due to the increased distance from the gas storage chamber 10, thereby preventing the fuel from diffusing into the gas storage chamber 10. At the same time, the pressure in the gas storage chamber can be stabilized, the gas fluctuation amplitude can be reduced, and the accuracy of the dual-fuel injector in injecting gas or fuel can be improved.

[0028] An oil return port 12 is provided on the injection main body 1, and a first oil return pipeline 13 is provided inside the needle valve 5. The oil return port 12 is connected to the first oil return pipeline 13, and an oil return groove 14 is provided on the outer wall of the needle valve 5. The oil return groove 14 of the present invention is arranged at a position higher than the oil storage chamber 8 and lower than the top surface of the valve body 6, and the first oil return pipeline 13 is connected to the oil return groove 14.

[0029] The needle valve 5 and the valve body 6 form an oil storage chamber 8, and the first oil inlet channel 7 delivers the fuel into the oil storage chamber 8. The bottom of the oil storage chamber 8 is connected to the fuel injection port 4. The outer wall of the needle valve 5 at the top of the oil storage chamber 8 is provided with an oil return groove 14. The fuel diffused upward will enter the first oil return pipeline 13 along the oil return groove 14, and finally be discharged to the outside from the oil return port 12, avoiding entering the air storage chamber 10 along the assembly gap, reducing the oil entering the air storage chamber 10, improving the injection accuracy of the dual-fuel injector, and enabling the engine to work normally and more efficiently.

[0030] An opening is formed on the lower side of the injection main body 1, a section of the valve body 6 is inserted into the opening, a fuel injection port 4 is provided on the area of the valve body 6 exposed outside the opening, the needle valve 5 abuts against the inner wall of the valve body 6, and the valve body 6 cover is connected to the gas injection port 3.

[0031] The area of the valve body 6 where the fuel injection port 4 is opened is exposed to the outside to facilitate fuel injection. During the injection process, the fuel and gas pipelines are independent of each other and can be injected separately. The gas is injected from the outside of the valve body 6, and the fuel is injected from the inside of the valve body 6. The valve body 6 can effectively separate the gas and fuel, so that the engine can work under different working conditions. There are three combustion modes: pure fuel, fuel ignited gas and pure gas. Customers can choose the working mode according to the specific situation to provide customers with the most economical usage mode.

[0032] The valve body 6 and the spray body 1 form a mating part. This mating part allows the internal valve body 6 to move up and down within the spray body 1, forming an annular cavity that can communicate with the gas storage chamber 10. The gas in the gas storage chamber 10 controls the valve body 6 to move up and down. A first spring 15 is installed in the mounting cavity on the upper side of the valve body 6. The other side of the first spring 15 abuts against the boss inside the spray body 1. The first spring 15 can maintain a normally closed state between the valve body 6 and the spray body 1 to prevent gas leakage.

[0033] The injection control unit 2 includes a first inner cavity 16 and an oil control port 17. The first inner cavity 16 is equipped with an oil control plate 18. The oil control plate 18 is provided with a first pressure relief hole 19. An oil control valve 20 is installed on the lower side of the oil control plate 18. The oil control electromagnet 21 controls the movement of the oil control valve 20. The first inner cavity 16 is connected to the installation cavity through a first connecting pipe, and the oil control port 17 is connected to the first pressure relief hole 19.

[0034] The injection control unit 2 includes a second inner cavity 23, in which an injection plate 24 is installed. A second pressure relief hole 25 is opened on the injection plate 24. An injection valve 26 is installed on the upper side of the injection plate 24. The injection solenoid 27 controls the movement of the injection valve 26. The lower side of the injection plate 24 is connected to the upper side of the needle valve 5 to form a flow cavity. The oil inlet 9 is connected to the flow cavity, and the flow cavity is connected to the second pressure relief hole 25.

[0035] When the control oil enters the first pressure relief hole 19, if the oil control electromagnet 21 adsorbs the oil control valve 20, the ball on the oil control valve 20 separates from the first pressure relief hole 19, the pressure in the first inner cavity 16 will be reduced, thereby reducing the pressure of the control oil entering the installation cavity, and the gas in the gas storage chamber 10 pushes the valve body 6 upward. At the same time, the fuel injection electromagnet 27 is started, so that the ball on the fuel injection valve 26 separates from the second pressure relief hole 25, so that the pressure in the second inner cavity 23 is reduced, and the fuel in the oil storage chamber 8 pushes the needle valve 5 upward, and finally the needle valve 5 and the valve body 6 can move upward at the same time, and the gas can be sprayed from the gas injection port 3; if in the fuel mode, it is necessary to start the fuel injection electromagnet 27, so that the ball on the fuel injection electromagnet 27 opens the second pressure relief hole 25, so that the pressure in the second inner cavity 23 is reduced, so that the fuel pushes the needle valve 5 to move upward and separate from the valve body 6, and finally the fuel can be sprayed out.

[0036] A second oil return pipe 22 is formed in the side wall of the first inner cavity 16 and communicates with the oil return port 12. A third oil return pipe 28 is formed in the inner wall above the fuel injection plate 24 and communicates with the oil return port 12. The provision of the second and third oil return pipes 22, 28 prevents fuel from accumulating inside the dual-fuel injector and prevents fuel from flowing into the air storage chamber 10, thereby improving the operating accuracy of the dual-fuel injector.

[0037] A raised portion is formed in the middle of the needle valve 5, and a second spring 29 is installed on the upper side of the raised portion. The second spring 29 abuts against the inner wall of the injection body 1. The second spring 29 can make the needle valve 5 abut against the valve body 6 to prevent fuel leakage during the non-injection process.

[0038] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A dual fuel injector, characterized in that: The invention comprises an injection main body (1) and an injection control part (2), wherein the injection control part (2) is installed at one end of the injection main body (1) and a gas injection port (3) is provided at the other end. A needle valve (5) is slidably installed on the injection main body (1), and a valve body (6) is slidably sleeved on the side of the needle valve (5) close to the gas injection port (3). A fuel injection port (4) is provided at the end of the valve body (6). A first oil inlet channel (7) is provided in the needle valve (5) along the axial direction. An oil storage chamber (8) is formed between the needle valve (5) and the valve body (6). When the needle valve (5) is opened, the first oil inlet channel (7) passes through the fuel injection port (4). The oil storage chamber (8) is communicated with the fuel injection port (4); an oil inlet (9) is provided on a side of the injection main body (1) close to the injection control unit (2); the oil inlet (9) is communicated with the first oil inlet channel (7); the injection main body (1) and the valve body (6) form an air storage chamber (10); an air inlet (11) is provided on the injection main body (1); when the valve body (6) is lifted, the air inlet (11) is communicated with the gas injection port (3) through the air storage chamber (10); and the injection control unit (2) can control the opening and closing of the fuel injection port (4) and the gas injection port (3).

2. The dual fuel injector according to claim 1, characterized in that An oil return port (12) is provided on the injection main body (1), a first oil return pipeline (13) is provided inside the needle valve (5), the oil return port (12) is communicated with the first oil return pipeline (13), an oil return groove (14) is provided on the outer wall of the needle valve (5), the first oil return pipeline (13) is communicated with the oil return groove (14).

3. The dual fuel injector according to claim 1, characterized in that An opening is formed on the lower side of the injection main body (1), a section of the valve body (6) is inserted into the opening, the fuel injection port (4) is provided on the area of the valve body (6) exposed outside the opening, the needle valve (5) abuts against the inner wall of the valve body (6), and the valve body (6) is covered on the gas injection port (3).

4. The dual fuel injector according to claim 2, characterized in that The valve body (6) and the injection main body (1) form a mating pair, and the annular cavity enclosed by the valve body (6) and the injection main body (1) is connected to the air storage cavity (10). A first spring (15) is installed in the installation cavity on the upper side of the valve body (6), and the other side of the first spring (15) abuts against the boss on the inner side of the injection main body (1).

5. The dual fuel injector according to claim 4, characterized in that The injection control unit (2) includes a first inner cavity (16) and an oil control port (17). The first inner cavity (16) is equipped with an oil control plate (18). The oil control plate (18) is provided with a first pressure relief hole (19). An oil control valve (20) is installed on the lower side of the oil control plate (18). An oil control electromagnet (21) controls the movement of the oil control valve (20). The first inner cavity (16) is connected to the installation cavity through a first connecting pipe, and the oil control port (17) is connected to the first pressure relief hole (19).

6. The dual fuel injector according to claim 5, characterized in that A second oil return pipe (22) is provided on the side wall of the first inner cavity (16), and the second oil return pipe (22) is communicated with the oil return port (12).

7. The dual fuel injector according to claim 2, characterized in that The injection control unit (2) includes a second inner cavity (23), an oil injection plate (24) is installed in the second inner cavity (23), a second pressure relief hole (25) is opened on the oil injection plate (24), an oil injection valve (26) is installed on the upper side of the oil injection plate (24), and an oil injection electromagnet (27) controls the movement of the oil injection valve (26), the lower side of the oil injection plate (24) is connected to the upper side of the needle valve (5) to form a flow cavity, the oil inlet (9) is connected to the flow cavity, and the flow cavity is connected to the second pressure relief hole (25).

8. The dual fuel injector according to claim 7, characterized in that A third oil return pipe (28) is provided on the inner wall of the upper side of the oil spray plate (24), and the third oil return pipe (28) is communicated with the oil return port (12).

9. The dual fuel injector according to claim 1, characterized in that A bulge is formed in the middle section of the needle valve (5), a second spring (29) is installed on the upper side of the bulge, and the second spring (29) abuts against the inner wall of the injection main body (1).

10. An internal combustion engine, characterized in that: The invention comprises a combustion chamber and the dual fuel injector according to claim 1, wherein the fuel injection port (4) and the gas injection port (3) are selectively connected to the combustion chamber.

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