Dual-fuel injector and dual-fuel engine

Abstract

The present invention relates to the field of engine fuel injection technology, and specifically discloses a dual-fuel injector and a dual-fuel engine, wherein the dual-fuel injector includes a needle valve body, a natural gas nozzle, and a diesel nozzle. The needle valve body is on the vertical projection plane of the combustion chamber, wherein the fan-shaped area S1 formed by the line connecting the injection points of two adjacent injection holes on the inner wall of the combustion chamber is the same. With such an arrangement, when the diesel first injected into the combustion chamber from the diesel nozzle triggers combustion through compression ignition, the energy and pressure generated by the combustion in each fan-shaped area S1 are consistent. Subsequently, each beam of natural gas injected from the natural gas nozzle will be quickly ignited. The equal air-fuel ratio in each fan-shaped area S1 makes the combustion consistent in each fan-shaped area, thereby improving the combustion efficiency in the entire combustion chamber. The dual-fuel injector of the present invention effectively solves the problem of insufficient combustion during operation of the dual-fuel injector in the prior art, resulting in low combustion efficiency.

Description

Technical Field

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

[0002] Currently, dual-fuel injectors are devices that inject two fuels, at a certain volume and pressure, into the engine cylinder either sequentially or simultaneously. Automotive engines use diesel as a secondary fuel and liquefied natural gas (LNG) as the primary fuel. Under normal circumstances, diesel is used for ignition, with only a small amount injected to initiate combustion. The dual-fuel system then determines whether to enter dual-fuel mode or diesel-only mode based on the engine's current operating conditions. However, in dual-fuel mode, due to the limited cylinder space and the injector's inherent structure, the natural gas and air mix unevenly, resulting in uneven combustion.

[0003] Existing technologies often use two or more injectors, essentially separating the natural gas and diesel injectors. This increases the number of components in the injection system and the complexity of assembling the entire engine system. Furthermore, when low-pressure and high-pressure gas injectors operate together, it's difficult to precisely control their opening and closing times, which can lead to incomplete combustion and the production of excessive soot or nitrogen oxides. Summary of the Invention

[0004] The object of the present invention is to provide a dual-fuel injector and a dual-fuel engine to solve the problem of insufficient combustion of the dual-fuel injector during operation in the prior art.

[0005] In one aspect, the present invention provides a dual-fuel injector, comprising: a needle valve body having an air hole passage and an oil hole passage arranged at intervals, one end of the needle valve body being capable of being disposed at the top of a combustion chamber of a cylinder body; a natural gas nozzle disposed at one end of the needle valve body, the natural gas nozzle having a plurality of injection holes, the plurality of injection holes being arranged at intervals circumferentially along an axis of the natural gas nozzle and all being connected to the air hole passage, wherein, on a vertical projection plane of the needle valve body, a sector area S1 formed by a line connecting injection landing points of two adjacent injection holes on an inner wall of the combustion chamber is the same; and a diesel nozzle disposed at one end of the needle valve body and connected to the oil hole passage.

[0006] As an optional technical solution for a dual-fuel injector, on the vertical projection plane of the needle valve body, the angles α formed by the line connecting the injection points of two adjacent injection holes on the inner wall of the combustion chamber and the center of the needle valve body are different.

[0007] As an optional technical solution for the dual-fuel injector, the maximum difference between the angles α formed by the line connecting the injection points of two adjacent injection holes on the inner wall of the combustion chamber and the center of the needle valve body is no more than 4°.

[0008] As an optional technical solution for a dual-fuel injector, the diesel nozzle has a plurality of fuel injection holes, which are arranged at circumferential intervals along the axis of the diesel nozzle and are all connected to the oil hole channel. The number of the plurality of fuel injection holes is the same as the number of the plurality of air injection holes. On the vertical projection plane of the needle valve body of the combustion chamber, the sector area S2 formed by the line connecting the injection landing points of two adjacent fuel injection holes on the inner wall of the combustion chamber is the same.

[0009] As an optional technical solution for dual-fuel injectors, on the vertical projection plane of the needle valve body, the angles β formed by the line connecting the injection points of two adjacent injection holes on the inner wall of the combustion chamber and the center of the needle valve body are different.

[0010] As an optional technical solution for a dual-fuel injector, the injection point of the injection hole on the combustion chamber is point A, and the injection point of the oil injection hole on the combustion chamber is point B. In the vortex direction of the combustion chamber, point A is located in a forward position relative to point B in the vortex direction.

[0011] As an optional technical solution for a dual-fuel injector, on the axial projection plane of the cylinder block, the injection point of the injection hole on the combustion chamber and the injection point of the oil injection hole on the combustion chamber are on the same horizontal plane.

[0012] As an optional technical solution for a dual-fuel injector, a line connecting the center point of the natural gas nozzle and the center point of the needle valve body and a line connecting the center point of the diesel nozzle and the center point of the needle valve body have an angle θ, 160°≤θ≤170°.

[0013] As an optional technical solution for the dual-fuel injector, the apertures of the plurality of injection holes are different from each other, and the apertures of the plurality of oil injection holes are different from each other.

[0014] On the other hand, the present invention provides a dual-fuel engine, comprising a cylinder block and the dual-fuel injector according to any of the above schemes, wherein the dual-fuel injector is arranged at the top of the combustion chamber of the cylinder block.

[0015] The beneficial effects of the present invention are:

[0016] The present invention provides a dual-fuel injector, which includes a needle valve body, a natural gas nozzle, and a diesel nozzle. The needle valve body has an air hole channel and an oil hole channel arranged at intervals; the natural gas nozzle has multiple injection holes. With the dual-fuel injector provided by the present invention, the needle valve body is on the vertical projection plane of the combustion chamber, and the fan-shaped area S1 formed by the line connecting the injection points of two adjacent injection holes on the inner wall of the combustion chamber is the same. With this arrangement, when the diesel first injected into the combustion chamber from the diesel nozzle triggers combustion through compression ignition, the energy and pressure generated by the combustion in each fan-shaped area S1 are consistent. Subsequently, each beam of natural gas injected from the natural gas nozzle will be quickly ignited. The equal air-fuel ratio in each fan-shaped area S1 makes the combustion consistent in each fan-shaped area, thereby improving the combustion efficiency in the entire combustion chamber. The dual-fuel injector of the present invention effectively solves the problem of insufficient combustion during operation of the dual-fuel injector in the prior art, resulting in low combustion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of a dual fuel injector in an embodiment of the present invention;

[0018] Figure 2 A cross-sectional view of a partial structure of a dual fuel injector according to an embodiment of the present invention;

[0019] Figure 3 is a cross-sectional view of a dual fuel injector according to an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of the jet hole spraying in the combustion chamber in an embodiment of the present invention;

[0021] Figure 5 Schematic diagram of the fuel injection hole spraying in the combustion chamber in an embodiment of the present invention;

[0022] Figure 6 Schematic diagram of the injection holes and the fuel injection holes in the combustion chamber according to an embodiment of the present invention;

[0023] Figure 7 Schematic diagram of a dual fuel injector injecting into a combustion chamber according to an embodiment of the present invention.

[0024] In the picture:

[0025] 1. Needle valve body; 11. Air hole channel; 12. Oil hole channel;

[0026] 2. Natural gas nozzle; 21. Fumarole;

[0027] 3. Diesel nozzle; 31. Fuel injection hole;

[0028] 4. Combustion chamber. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0032] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0033] like Figures 1 to 7As shown, this embodiment provides a dual-fuel injector comprising a needle valve body 1, a natural gas nozzle 2, and a diesel nozzle 3. The needle valve body 1 has an air hole passage 11 and an oil hole passage 12 spaced apart from each other. One end of the needle valve body 1 can be positioned at the top of the combustion chamber 4 of the cylinder block. The natural gas nozzle 2 is positioned at one end of the needle valve body 1 and has a plurality of injection holes 21 spaced apart circumferentially about the axis of the natural gas nozzle 2 and all connected to the air hole passage 11. In a vertical projection of the needle valve body 1 onto the combustion chamber 4, the sector area S1 formed by the line connecting the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 is the same. The diesel nozzle 3 is positioned at one end of the needle valve body 1 and is connected to the oil hole passage 12.

[0034] With the dual-fuel injector provided by the present invention, the needle valve body 1 is on the vertical projection plane of the combustion chamber 4, wherein the fan-shaped area S1 formed by the line connecting the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 is the same. With this arrangement, when the diesel first injected into the combustion chamber 4 from the diesel nozzle 3 triggers combustion through compression ignition, the energy and pressure generated by the combustion in each fan-shaped area S1 are consistent. Subsequently, each beam of natural gas injected from the natural gas nozzle 2 will be quickly ignited. The equal air-fuel ratio in each fan-shaped area S1 makes the combustion in each fan-shaped area S1 consistent, thereby improving the combustion efficiency in the entire combustion chamber. The dual-fuel injector of the present invention effectively solves the problem of insufficient combustion during operation of the dual-fuel injector in the prior art, resulting in low combustion efficiency. At the same time, the deviation of the fan-shaped area S1 is ensured to be within a certain range, so that the air volume within the range of each fan-shaped area S1 can be consistent, and the air-fuel ratio within each fan-shaped area S1 can be further equalized.

[0035] In some embodiments, as Figure 4 As shown, the needle valve body 1 is projected vertically onto the combustion chamber 4, wherein the angles α formed by the line connecting the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 and the center of the needle valve body 1 are different. This arrangement ensures that the natural gas ejected from each injection hole 21 moves at the same angle along the direction of the airflow in the combustion chamber 4, thereby achieving consistent combustion in each sector area S1 and improving the combustion efficiency in the entire combustion chamber 4.

[0036] Furthermore, in this embodiment, the maximum difference between the angles α formed by the line connecting the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 and the center of the needle valve body 1 is no greater than 4°. This arrangement further ensures consistent combustion within each sector area S1, resulting in an equal air-fuel ratio within each sector area S1.

[0037] Similarly, if Figure 1 、 Figure 2 and Figure 5As shown, the diesel nozzle 3 has multiple injection holes 31, which are arranged at circumferential intervals along the axis of the diesel nozzle 3 and are all connected to the oil hole channel 12. In the vertical projection plane of the needle valve body 1 on the combustion chamber 4, the fan-shaped area S2 formed by the line connecting the injection points of two adjacent injection holes 31 on the inner wall of the combustion chamber 4 is the same. In addition, the number of the multiple injection holes 31 is the same as the number of the multiple air injection holes 21. This arrangement ensures that the deviation of the fan-shaped area S2 is within a certain range. In this way, the amount of air within each fan-shaped area S2 can be consistent because the amount of diesel sprayed by each injection hole 31 is the same, further ensuring that the air-fuel ratio within each fan-shaped area S2 is equal. Specifically, as the air flow moves, the diesel sprayed by each injection hole 31 is evenly mixed with the air within the fan-shaped area S2, making combustion more rapid and complete, thereby improving the combustion efficiency of the entire cylinder.

[0038] Furthermore, in the vertical projection of the needle valve body 1 onto the combustion chamber 4, the angle β formed between the injection points of two adjacent injection holes 31 on the inner wall of the combustion chamber 4 and the line connecting the center of the needle valve body 1 is different. This arrangement also ensures that the amount of diesel sprayed from each injection hole 31 moves at a consistent angle with the direction of airflow within the combustion chamber 4, thereby achieving consistent combustion within each sector area S2 and improving combustion efficiency within the entire combustion chamber 4.

[0039] Specifically, if Figure 6 As shown, the swirl direction is clockwise. The injection point of the fuel injection hole 21 on the combustion chamber 4 is point A, and the injection point of the fuel injection hole 31 on the combustion chamber 4 is point B. In the swirl direction of the combustion chamber 4, point A is located ahead of point B in the swirl direction. It can be seen that in the swirl direction, when viewed in a clockwise direction, point A is ahead of point B. This results in the diesel burning first. As the airflow swirls, the flame front generated by the diesel combustion quickly ignites the subsequently injected natural gas, resulting in faster combustion and further improving the combustion efficiency within the entire combustion chamber 4.

[0040] In this embodiment, if Figure 7 As shown, on the axial projection of the cylinder block, the injection point of the fuel injection hole 21 on the combustion chamber 4 is on the same horizontal plane as the injection point of the fuel injection hole 31 on the combustion chamber 4. This arrangement allows for more stable and uniform flame propagation during combustion, reducing incomplete combustion, thereby optimizing combustion efficiency, reducing harmful gas emissions, and contributing to more stable engine power output in dual-fuel mode.

[0041] Specifically, if Figures 1 to 3As shown, the line connecting the center of the natural gas nozzle 2 and the center of the needle valve body 1, and the line connecting the center of the diesel nozzle 3 and the center of the needle valve body 1, form an angle θ, with a value of 160°≤θ≤170°. This arrangement facilitates the placement of the gas injection holes 21 and the fuel injection holes 31 and avoids machining interference. If the centers of the natural gas nozzle 2, the diesel nozzle 3, and the needle valve body 1 were aligned, the tool would hit the tip of the diesel nozzle 3 when machining the two gas injection holes 21 near the needle valve body 1 due to space limitations. The angle θ between the line connecting the center of the natural gas nozzle 2 and the center of the needle valve body 1, and the line connecting the center of the diesel nozzle 3 and the center of the needle valve body 1, can be selected as appropriate based on actual conditions, specifically 160°, 165°, or 170°. In this embodiment, the angle θ between the line connecting the center of the natural gas nozzle 2 and the center of the needle valve body 1, and the line connecting the center of the diesel nozzle 3 and the center of the needle valve body 1, is 161.5°.

[0042] Alternatively, in some embodiments, the apertures of the plurality of air injection holes 21 are different from each other, and the apertures of the plurality of oil injection holes 31 are different from each other.

[0043] This embodiment also provides a dual-fuel engine, comprising a cylinder block and the dual-fuel injector of the above-described embodiment, the dual-fuel injector being disposed at the top of the combustion chamber 4 of the cylinder block. In the dual-fuel engine provided by the present invention, the needle valve body 1 is positioned on the vertical projection plane of the combustion chamber 4, wherein the sector area S1 formed by the line connecting the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 is identical. With this arrangement, when the diesel fuel injected into the combustion chamber 4 from the diesel nozzle 3 initiates combustion through compression ignition, the energy and pressure generated by the combustion within each sector area S1 are consistent. Subsequently, the natural gas jets injected from the natural gas nozzle 2 are rapidly ignited, and the equal air-fuel ratio within each sector area S1 results in consistent combustion within each sector area S1, thereby improving the combustion efficiency within the entire combustion chamber. The dual-fuel engine of the present invention effectively solves the problem of insufficient combustion during operation of dual-fuel injectors in the prior art, resulting in low combustion efficiency. At the same time, the deviation of the sector area S1 is ensured to be within a certain range, so that the air volume within each sector area S1 can be consistent, and further the air-fuel ratio within each sector area S1 can be equal.

[0044] The working process and advantages of the present invention are as follows:

[0045] Working process: The dual-fuel injector first injects diesel into the combustion chamber through natural gas and diesel nozzles. A small amount of diesel enters the combustion chamber and is pre-compression-ignited. Natural gas is then injected into the combustion chamber through the air passage and jet holes, mixing with air. The flame formed by the diesel combustion quickly spreads to the surrounding area, igniting the natural gas. During one cycle of the dual-fuel injector, diesel is then injected into the combustion chamber, followed by natural gas, and this cycle repeats.

[0046] The dual-fuel injector provided by the present invention utilizes the spatial arrangement of the natural gas nozzle and the diesel nozzle, and the design of the injection holes at different angles, so that the diesel injected into each injection hole is evenly mixed with the air in the sector area S2 to form the same air-fuel ratio, so that the combustion is faster and more complete, thereby rapidly increasing the temperature and pressure in the cylinder body, creating good conditions for the combustion of natural gas; through the design of the injection holes at different angles, the energy and pressure generated by the combustion in each sector area S1 of each natural gas injection are consistent, and each injected natural gas beam will be quickly ignited, the combustion is more stable, and the situation of incomplete combustion is reduced, thereby optimizing the combustion efficiency, reducing harmful gas emissions, and helping the engine to output power more stably in the dual-fuel mode.

[0047] 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. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. 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: include: A needle valve body (1) having an air hole channel (11) and an oil hole channel (12) arranged at intervals, wherein one end of the needle valve body (1) can be arranged at the top of a combustion chamber (4) of a cylinder body; A natural gas nozzle (2) is provided at one end of the needle valve body (1), the natural gas nozzle (2) having a plurality of jet holes (21), the plurality of jet holes (21) being arranged at intervals along the circumference of the axis of the natural gas nozzle (2) and all being in communication with the gas hole channel (11), and a sector area S1 formed by a line connecting the injection points of two adjacent jet holes (21) on the inner wall of the combustion chamber (4) on a vertical projection plane of the needle valve body (1) on the combustion chamber (4) being the same; A diesel nozzle (3) is provided at one end of the needle valve body (1) and is in communication with the oil hole channel (12); On the vertical projection plane of the needle valve body (1) on the combustion chamber (4), angles α formed by the line connecting the injection points of two adjacent injection holes (21) on the inner wall of the combustion chamber (4) and the center of the needle valve body (1) are different; The maximum difference between the angles α formed by the line connecting the injection points of two adjacent injection holes (21) on the inner wall of the combustion chamber (4) and the center of the needle valve body (1) is no more than 4°.

2. The dual fuel injector according to claim 1, characterized in that The diesel nozzle (3) has a plurality of oil injection holes (31), the plurality of oil injection holes (31) are arranged at intervals along the circumferential direction of the axis of the diesel nozzle (3), and are all connected to the oil hole channel (12). The number of the plurality of oil injection holes (31) is the same as the number of the plurality of air injection holes (21). On the vertical projection plane of the needle valve body (1) on the combustion chamber (4), the sector area S2 formed by the line connecting the injection landing points of two adjacent oil injection holes (31) on the inner wall of the combustion chamber (4) is the same.

3. The dual fuel injector according to claim 2, characterized in that On the vertical projection plane of the needle valve body (1) on the combustion chamber (4), angles β formed by the line connecting the injection points of two adjacent injection holes (31) on the inner wall of the combustion chamber (4) and the center of the needle valve body (1) are different.

4. The dual fuel injector according to claim 2, characterized in that The injection point of the injection hole (21) on the combustion chamber (4) is point A, and the injection point of the oil injection hole (31) on the combustion chamber (4) is point B. In the vortex direction of the combustion chamber (4), point A is located in front of point B in the vortex direction.

5. The dual fuel injector according to claim 4, characterized in that On the axial projection surface of the cylinder body, the injection point of the injection hole (21) on the combustion chamber (4) and the injection point of the oil injection hole (31) on the combustion chamber (4) are on the same horizontal plane.

6. The dual fuel injector according to claim 1, characterized in that The line connecting the center point of the natural gas nozzle (2) and the center point of the needle valve body (1) and the line connecting the center point of the diesel nozzle (3) and the center point of the needle valve body (1) have an angle θ, 160°≤θ≤170°.

7. The dual fuel injector according to claim 2, characterized in that The apertures of the plurality of jet holes (21) are different from each other, and the apertures of the plurality of oil injection holes (31) are different from each other.

8. A dual-fuel engine, characterized in that: It comprises a cylinder body and a dual-fuel injector according to any one of claims 1 to 7, wherein the dual-fuel injector is arranged at the top of the combustion chamber (4) of the cylinder body.

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