Dual-fuel injector and dual-fuel engine

Abstract

The invention relates to the technical field of engine fuel injection, and particularly discloses a dual-fuel injector and a dual-fuel engine, and the dual-fuel injector comprises a needle valve main body, a natural gas nozzle and a diesel nozzle. The needle valve main body is arranged on a vertical projection surface of a combustion chamber, and fan-shaped areas S1 formed by connecting lines between injection drop points of two adjacent gas injection holes on the inner wall of the combustion chamber are the same, so that when diesel oil injected into the combustion chamber from the diesel oil nozzle firstly initiates combustion through compression ignition, energy and pressure generated by combustion in the fan-shaped areas S1 are consistent, and the combustion effect is good; and then each beam of natural gas sprayed from the natural gas nozzle can be quickly ignited, and the combustion in each fan-shaped area is consistent due to the equal air-fuel ratio in each fan-shaped area S1, so that the combustion efficiency in the whole combustion chamber is improved. By means of the dual-fuel injector, the problem that in the prior art, due to the fact that combustion is insufficient when a dual-fuel injector works, combustion efficiency is low is effectively solved.

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] At present, dual-fuel injectors are devices that inject two fuels of a certain amount and pressure into the engine cylinders one after the other or simultaneously. Among them, automotive engines use diesel as auxiliary fuel and liquefied natural gas (LNG) as the main fuel. Under normal circumstances, diesel is used for ignition, and only a small amount of diesel is injected to initiate combustion. The dual-fuel system then determines whether to enter dual-fuel mode or pure diesel mode based on the current working conditions of the engine. However, in dual-fuel mode, due to the limitations of the cylinder space and the injector's own structure, there is an uneven mixing of natural gas and air, resulting in uneven combustion.

[0003] In the prior art, two or more injectors are mostly used, that is, the natural gas injector and the diesel injector are separated independently. Two or more injectors increase the number of parts of the injection system and increase the difficulty of assembling the entire engine system. In addition, when the low-pressure gas injector and the high-pressure gas injector work together, it is difficult to accurately control the opening and closing time of the low-pressure gas injector and the high-pressure gas injector, which easily leads to incomplete combustion and excessive carbon soot or nitrogen oxides. Summary of the invention

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

[0005] On the one hand, the present invention provides a dual-fuel injector, which includes: a needle valve body, having an air hole channel and an oil hole channel arranged at intervals, and one end of the needle valve body can be set at the top of the combustion chamber of the cylinder body; a natural gas nozzle, which is arranged at one end of the needle valve body, and the natural gas nozzle has a plurality of injection holes, and the plurality of injection holes are arranged at intervals along the circumferential direction of the axis of the natural gas nozzle, and are all connected to the air hole channel, and the fan area S1 formed by the line connecting the injection landing points of two adjacent injection holes on the inner wall of the combustion chamber on the vertical projection plane of the needle valve body is the same; a diesel nozzle, which is arranged at one end of the needle valve body and is connected to the oil hole channel.

[0006] As an optional technical solution for dual-fuel injectors, 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, the plurality of fuel injection holes 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 gas injection holes, and the needle valve body is on a vertical projection plane of the combustion chamber, and 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 fuel injection hole on the combustion chamber is point B. In the swirl direction of the combustion chamber, point A is located in front of point B in the swirl 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 the dual fuel injector, the line between the center point of the natural gas nozzle and the center point of the needle valve body and the line between 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 a 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 a plurality of jet 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, wherein the fan-shaped area S1 formed by the line between the injection points of two adjacent jet 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, and then 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 of the dual-fuel injector in the prior art during operation, 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 in 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 A 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 jet hole and the fuel injection hole spraying in the combustion chamber in an embodiment of the present invention;

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

[0024] In the figure:

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

[0026] 2. Natural gas nozzle; 21. Jet hole;

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

[0028] 4. Combustion chamber. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot 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 "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates 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 clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Embodiments of the present invention are described in detail below, examples of which 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 only used to explain the present invention, and cannot be understood as limiting the present invention.

[0033] like Figures 1 to 7As shown, this embodiment provides a dual-fuel injector, which includes a needle valve body 1, a natural gas nozzle 2 and a diesel nozzle 3. The needle valve body 1 has an air hole channel 11 and an oil hole channel 12 arranged at intervals, and one end of the needle valve body 1 can be arranged at the top of the combustion chamber 4 of the cylinder body; the natural gas nozzle 2 is arranged at one end of the needle valve body 1, and the natural gas nozzle 2 has a plurality of injection holes 21, and the plurality of injection holes 21 are arranged at intervals along the circumferential direction of the axis of the natural gas nozzle 2, and are all connected to the air hole channel 11. On the vertical projection plane of the needle valve body 1 on the combustion chamber 4, the fan-shaped area S1 formed by the line between 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 arranged at one end of the needle valve body 1, and is connected to the oil hole channel 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 between the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 is the same. With such a configuration, 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, and then each beam of natural gas injected from the natural gas nozzle 2 will be quickly ignited, and 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 of the dual-fuel injector in the prior art during operation, resulting in low combustion efficiency. At the same time, it is ensured that the deviation of the fan-shaped area S1 is within a certain range, so that the amount of air within the range of each fan-shaped area S1 can be consistent, and the air-fuel ratio in each fan-shaped area S1 can be further equalized.

[0035] In some embodiments, Figure 4 As shown, the needle valve body 1 is on the vertical projection plane of the combustion chamber 4, wherein the angles α formed by the line between 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. In this way, the natural gas ejected from each injection hole 21 can move at the same angle along the direction of the airflow in the combustion chamber 4, thereby making the combustion in each sector area S1 consistent, thereby improving the combustion efficiency in the entire combustion chamber 4.

[0036] Furthermore, in this embodiment, the maximum difference between the angle 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°. This arrangement further ensures that the combustion in each sector area S1 is consistent, so that the air-fuel ratio in each sector area S1 is equal.

[0037] Similarly, if Figure 1 , Figure 2 and Figure 5As shown, the diesel nozzle 3 has a plurality of injection holes 31, which are arranged at intervals along the circumference of the axis of the diesel nozzle 3 and are all connected to the oil hole channel 12; wherein, on the vertical projection plane of the needle valve body 1 on the combustion chamber 4, the sector area S2 formed by the line between the injection points of two adjacent injection holes 31 on the inner wall of the combustion chamber 4 is the same. Moreover, the number of the plurality of injection holes 31 is the same as the number of the plurality of injection holes 21; such an arrangement ensures that the deviation of the sector area S2 is within a certain range, so that the amount of air within each sector area S2 can be consistent, because the amount of diesel sprayed from each injection hole 31 is the same, and further the air-fuel ratio within each sector area S2 is equal. Specifically, with the movement of the airflow, the diesel sprayed from each injection hole 31 is evenly mixed with the air within the sector area S2, so that the combustion is faster and more complete, and the combustion efficiency in the entire cylinder is improved.

[0038] Furthermore, on the vertical projection plane of the needle valve body 1 on the combustion chamber 4, the 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. This arrangement can also make the movement angle of the diesel volume sprayed from each injection hole 31 consistent with the direction of the air flow in the combustion chamber 4, so that the combustion in each sector area S2 is consistent, and the combustion efficiency in the entire combustion chamber 4 is improved.

[0039] Specifically, Figure 6 As shown, the vortex direction is clockwise, the injection point of the jet 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 vortex direction of the combustion chamber 4, point A is located in front of point B in the vortex direction. It can be seen that in the vortex direction, when viewed in the clockwise direction, point A is located in front of point B. The effect produced in this way is that the diesel burns first, and with the vortex motion of the airflow, the flame front generated by the diesel combustion quickly ignites the natural gas injected subsequently, making the combustion faster, further improving the combustion efficiency in the entire combustion chamber 4.

[0040] In this embodiment, if Figure 7 As shown, 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 fuel injection hole 31 on the combustion chamber 4 are at the same horizontal plane. In this way, during the combustion process, injection at the same horizontal plane position can make the flame propagation more stable and uniform, reduce the situation of incomplete combustion, thereby optimizing the combustion efficiency, reducing harmful gas emissions, and helping the engine to output power more stably in dual fuel mode.

[0041] Specifically, Figures 1 to 3As shown, the line between the center point of the natural gas nozzle 2 and the center point of the needle valve body 1 and the line between 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°. Such a setting is conducive to the arrangement of each jet hole 21 and the injection hole 31, and avoids processing interference; if the center of the natural gas nozzle 2, the center of the diesel nozzle 3 and the center of the needle valve body 1 are on a straight line, due to space limitations, when processing two jet holes 21 close to the needle valve body 1, the tool will hit the head of the diesel nozzle 3. Among them, the line between the center point of the natural gas nozzle 2 and the center point of the needle valve body 1 and the line between the center point of the diesel nozzle 3 and the center point of the needle valve body 1 have an angle θ, which can be selected according to actual conditions. The specific angle can be 160°, 165° or 170°. In this solution, the line between the center point of the natural gas nozzle 2 and the center point of the needle valve body 1 and the line between the center point of the diesel nozzle 3 and the center point of the needle valve body 1 have an angle θ of 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, including a cylinder body and the dual-fuel injector in the above scheme, and the dual-fuel injector is arranged at the top of the combustion chamber 4 of the cylinder body. With the dual-fuel engine 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 between the injection points of two adjacent injection holes 21 on the inner wall of the combustion chamber 4 is the same. With such an 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, and then each beam of natural gas injected from the natural gas nozzle 2 will be quickly ignited, and 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 engine of the present invention effectively solves the problem of insufficient combustion of the dual-fuel injector during operation 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 the natural gas nozzle and the diesel nozzle. A small amount of diesel enters the combustion chamber and is compressed and ignited in advance; then the natural gas is injected into the combustion chamber through the air hole channel and the jet hole to mix with the air. The flame formed after the diesel burns quickly spreads to the surroundings and ignites the natural gas. In a cycle of the dual-fuel injector, diesel is then injected into the combustion chamber, and then natural gas is injected into the combustion chamber, and the cycle repeats.

[0046] The dual-fuel injector provided by the present invention arranges the natural gas nozzle and the diesel nozzle in space, and designs the injection holes at different angles. 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, so that the temperature and pressure in the cylinder body increase rapidly, 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 clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A 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 arranged at one end of the needle valve body (1), the natural gas nozzle (2) having a plurality of gas injection holes (21), the plurality of gas injection holes (21) being arranged at intervals along the circumferential direction of the axis of the natural gas nozzle (2), and all being in communication with the gas hole channel (11), and the sector area S1 formed by the line connecting the injection points of two adjacent gas injection holes (21) on the inner wall of the combustion chamber (4) on the vertical projection plane of the needle valve body (1) on the combustion chamber (4) is the same; A diesel nozzle (3) is arranged at one end of the needle valve body (1) and is communicated with the oil hole channel (12).

2. The dual fuel injector according to claim 1, characterized in that: 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.

3. The dual fuel injector according to claim 2, characterized in that: 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°.

4. The dual fuel injector according to claim 1, characterized in that The diesel nozzle (3) has a plurality of fuel injection holes (31), the plurality of fuel 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 fuel injection holes (31) is the same as the number of the plurality of gas injection holes (21), and 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 points of two adjacent fuel injection holes (31) on the inner wall of the combustion chamber (4) is the same.

5. The dual fuel injector according to claim 4, 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.

6. The dual fuel injector according to claim 4, 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 fuel 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.

7. The dual fuel injector according to claim 6, 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.

8. 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°.

9. The dual fuel injector according to claim 4, characterized in that The apertures of the plurality of injection holes (21) are different from each other, and the apertures of the plurality of oil injection holes (31) are different from each other.

10. 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 9, wherein the dual-fuel injector is arranged at the top of a combustion chamber (4) of the cylinder body.

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