A flat-bottom dual fuel injector structure and a dual fuel engine

Abstract

The utility model discloses a kind of flat bottom dual-fuel injector structure and dual-fuel engine, including the injector body, middle body and needle valve body sequentially connected from top to bottom, the inside of the needle valve body is provided with first fuel needle valve, the inside of the first fuel needle valve is provided with second fuel needle valve, the bottom surface of the first fuel needle valve and the bottom surface of the needle valve body are located on the same plane, a plurality of first fuel injection holes are provided on the needle valve body, the bottom of the first fuel needle valve is provided with a plurality of second fuel injection holes, the injection cone angle of the second fuel injection hole is less than set angle;The bottom of the dual-fuel injector of the utility model is plane structure, so that the heated area of fuel injector exposed in combustion chamber is reduced, the temperature of fuel injection hole can be effectively reduced, so as to reduce the risk of coking.

Description

Technical Field

[0001] This utility model belongs to the technical field of dual-fuel injectors, specifically relating to a flat-bottomed dual-fuel injector structure and a dual-fuel engine. Background Technology

[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.

[0003] In direct injection engines, the fuel injectors are mounted on the cylinder head, with their heads exposed inside the engine's combustion chamber. During engine operation, the combustion chamber is in a constantly changing, high-temperature, and high-pressure environment, which can easily cause the fuel injector head to overheat, leading to fuel coking at that point. The accumulated coking products eventually clog the injection holes, resulting in abnormal combustion and affecting engine performance and emissions.

[0004] Existing dual-fuel injector structures, because their heads simultaneously have two fuel injection holes, require methanol injection holes and fuel injection holes to be set at the injector ends respectively. In order for fuel to be smoothly injected into the cylinder, a larger fuel head needs to be designed. A larger fuel head has a larger heat-receiving area, so the fuel head temperature is high. In addition, the fuel injection hole is located below the methanol injection hole, and a fuel injection hole protrusion structure is usually set so that the fuel injection hole is located at the very end of the injector. Because it is closer to the combustion center and farthest from the cylinder head cooling water jacket, the fuel injection hole located at the bottom has the greatest risk of coking and is more likely to produce high-temperature coking. Utility Model Content

[0005] The purpose of this invention is to provide a flat-bottomed dual-fuel injector structure and a dual-fuel engine, which effectively reduces the injector head volume and lowers the risk of head coking.

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0007] In a first aspect, embodiments of this utility model provide a flat-bottomed dual-fuel injector structure, comprising an injector body, an intermediate body, and a needle valve body connected sequentially from top to bottom. A first fuel needle valve is disposed inside the needle valve body, and a second fuel needle valve is disposed inside the first fuel needle valve. The bottom surface of the first fuel needle valve and the bottom surface of the needle valve body are located on the same plane. A plurality of first fuel injection holes are disposed on the needle valve body, and a plurality of second fuel injection holes are disposed at the bottom of the first fuel needle valve. The injection cone angle of the second fuel injection holes is less than a set angle.

[0008] As a further technical solution, a fuel pressure chamber is formed between the bottom of the second fuel needle valve and the bottom of the first fuel needle valve, and the second fuel injection hole is connected to the fuel pressure chamber.

[0009] As a further technical solution, the set angle α max The following conditions must be met: α max =arctan[(D2 / 2-A min -D1 / 2) / B min ], where D1 represents the diameter of the second fuel injection orifice, D2 represents the diameter of the outer cylindrical surface at the bottom of the first fuel needle valve, and A min B represents the minimum distance between the second fuel injection orifice and the bottom outer cylindrical surface of the first fuel needle valve. min This indicates the minimum distance between the bottom of the fuel pressure chamber and the lower plane of the first fuel needle valve.

[0010] As a further technical solution, the minimum distance between the second fuel injection hole and the bottom outer cylindrical surface of the first fuel needle valve is greater than 0.7 mm, and the minimum distance between the bottom of the fuel pressure chamber and the lower plane of the first fuel needle valve is greater than 0.7 mm.

[0011] As a further technical solution, the injector body, intermediate body and needle valve body are fastened together by a lower fastening sleeve.

[0012] As a further technical solution, the top of the injector body is connected to the control body via an upper fastening sleeve, and a connector is installed on the top of the control body. The connector is connected to the injector control circuit.

[0013] As a further technical solution, the upper part of the injector body is provided with a first fuel inlet, which is connected to a first fuel pipeline, and the upper part of the control body is provided with a second fuel inlet, which is connected to a second fuel pipeline.

[0014] As a further technical solution, a first fuel needle valve spring is provided above the first fuel needle valve, and a second fuel needle valve spring is provided above the second fuel needle valve.

[0015] As a further technical solution, the height of the first fuel injection hole is greater than the height of the second fuel injection hole.

[0016] Secondly, embodiments of this utility model provide a dual-fuel engine, including the flat-bottomed dual-fuel injector structure described in the first aspect.

[0017] The beneficial effects of the above-described embodiments of this utility model are as follows:

[0018] The flat-bottomed dual-fuel injector structure provided by this invention moves the positions of the second fuel injection orifice and the fuel pressure chamber upwards. Therefore, an additional protrusion is no longer needed at the bottom of the first fuel needle valve; instead, a flat structure is adopted, flush with the bottom surface of the needle valve body. Compared to the protruding structure of the prior art, the heat-exposed area in the combustion chamber of this invention is reduced, which can effectively lower the temperature of the second fuel injection orifice, thereby reducing the risk of coking. Simultaneously, the injection cone angle of the second fuel injection orifice should meet a given formula limit to ensure the reliability of the injector.

[0019] The flat-bottomed dual-fuel injector structure provided by this utility model uses an upper fastening sleeve and a lower fastening sleeve to rigidly connect the four main components, integrating a dual fuel passage, a dual needle valve system and a control unit in a limited space, which significantly saves installation space; in addition, the modular structure design facilitates disassembly and maintenance, and the separable structure of the needle valve body and the injector body facilitates the replacement of individual components. Attached Figure Description

[0020] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0021] Figure 1 This is a schematic diagram of the overall structure of the flat-bottomed dual-fuel injector of this utility model.

[0022] Figure 2 yes Figure 1 A magnified view of section I in the middle.

[0023] The diagram is for illustrative purposes only.

[0024] The components include: 1. Injector body; 2. Intermediate body; 3. Needle valve body; 4. First fuel needle valve; 5. Second fuel needle valve; 6. Lower fastening sleeve; 7. Control body; 8. Upper fastening sleeve; 9. Connector; 10. First fuel needle valve spring; 11. Second fuel needle valve spring; 12. First fuel inlet; 13. Second fuel inlet.

[0025] 3-1, First fuel injection port; 4-1, Second fuel injection port; 4-2, Lower plane of the first fuel needle valve; 4-3, Fuel pressure chamber. Detailed Implementation

[0026] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] Example 1

[0028] Existing dual-fuel injectors typically have their fuel injection orifices located on a protrusion at the bottom of the needle valve. This results in the fuel injection orifice being closest to the combustion center of the combustion chamber. In addition, the protrusion increases the heat-receiving area at the bottom of the needle valve, which will raise the temperature of the fuel injection orifice and pose a risk of coking.

[0029] To address the aforementioned problems, in a typical embodiment of this utility model, such as... Figure 1 and Figure 2 As shown, a flat-bottomed dual-fuel injector structure is provided, including an injector body 1, an intermediate body 2, and a needle valve body 3 connected sequentially from top to bottom. A first fuel needle valve 4 is disposed inside the needle valve body 3, and a second fuel needle valve 5 is disposed inside the first fuel needle valve 4. The bottom of the first fuel needle valve 4 and the bottom surface of the needle valve body 3 are located on the same plane. A plurality of first fuel injection holes 3-1 are disposed on the needle valve body 3, and a plurality of second fuel injection holes 4-1 are disposed at the bottom of the first fuel needle valve 4. The injection cone angle of the second fuel injection holes 4-1 is less than a set angle.

[0030] Furthermore, a fuel pressure chamber 4-3 is formed between the bottom of the second fuel needle valve 5 and the bottom of the first fuel needle valve 4, and the second fuel injection hole 3-1 is connected to the fuel pressure chamber 4-3.

[0031] Furthermore, the set angle α max The following conditions must be met: α max =arctan[(D2 / 2-A min -D1 / 2) / B min ], where D1 represents the diameter of the second fuel injection orifice, D2 represents the diameter of the outer cylindrical surface at the bottom of the first fuel needle valve, and A min B represents the minimum distance between the second fuel injection orifice and the bottom outer cylindrical surface of the first fuel needle valve. min This indicates the minimum distance between the bottom of the fuel pressure chamber and the lower plane 4-2 of the first fuel needle valve.

[0032] Furthermore, the minimum distance between the second fuel injection orifice and the bottom outer cylindrical surface of the first fuel needle valve is greater than 0.7 mm, and the minimum distance between the bottom of the fuel pressure chamber and the lower plane 4-2 of the first fuel needle valve is greater than 0.7 mm. If these two distances are too small, the reliability of the injector will be affected. Therefore, the minimum distance between the two distances should be greater than 0.7 mm to ensure the performance of the injector.

[0033] By limiting the injection cone angle of the second fuel injection orifice, the injection angle of the second fuel injection orifice can be made to satisfy the condition that the bottom of the dual fuel injector is a flat plane, wherein A min and B minThe material used for the first fuel needle valve is determined based on its thermal fatigue resistance; different materials have different thermal fatigue resistance. Although the bottom of the dual-fuel injector in this embodiment is flat, it will still be heated. Therefore, A min and B min The selection of [the material / mechanism] needs to ensure it possesses a certain degree of resistance to thermal fatigue, thereby preventing cracks from appearing at the location of the first fuel injection hole at the bottom of the first fuel needle valve due to heat. Those skilled in the art can obtain A through experiments. min and B min , obtain A min and B min The specific process is based on existing technology and will not be elaborated here.

[0034] In this embodiment, the injector body 1, intermediate body 2, and needle valve body 3 are fastened together by a lower fastening sleeve 6. The top of the injector body 1 is connected to the control body 7 via an upper fastening sleeve 8. A connector 9 is installed on the top of the control body 7, and the connector 9 is connected to the injector control circuit. The intermediate body, control body, and connector are all existing structures. This embodiment divides the overall structure of the dual-fuel injector into sections, which are connected and installed using lower and upper fastening sleeves. The modular design facilitates disassembly and maintenance, and the separable structure of the needle valve body and injector body allows for easy replacement of individual components.

[0035] Furthermore, the upper part of the injector body 1 is provided with a first fuel inlet 12, which is connected to a first fuel pipeline. The upper part of the control body 7 is provided with a second fuel inlet 13, which is connected to a second fuel pipeline. A first fuel chamber is formed between the needle valve body 3 and the first fuel needle valve 4. The first fuel enters the first fuel chamber through the first fuel inlet 12 and is injected through the first fuel nozzle 3-1 on the needle valve body 3. A second fuel chamber is formed between the first fuel needle valve 4 and the second fuel needle valve 5. The second fuel enters the second fuel chamber through the second fuel inlet 13 and is injected through the second fuel nozzle 4-1 on the first fuel chamber.

[0036] In this embodiment, the first fuel can be natural gas, methanol, hydrogen, or other fuels, and the second fuel is usually diesel.

[0037] In this embodiment, a first fuel needle valve spring 10 is provided above the first fuel needle valve 4, and the first fuel needle valve spring 10 applies a settling force to the first fuel needle valve 4. A second fuel needle valve spring 11 is provided above the second fuel needle valve 5, and the second fuel needle valve spring 11 applies a settling force to the second fuel needle valve 5.

[0038] In this embodiment, the height of the first fuel nozzle 3-1 is greater than the height of the second fuel nozzle 4-1, enabling independent injection of the two fuels without interference between them.

[0039] The flat-bottomed dual-fuel injector structure provided in this embodiment moves the positions of the second fuel injection orifice and the fuel pressure chamber upwards. Therefore, an additional protrusion is no longer needed at the bottom of the first fuel needle valve; instead, a flat structure is adopted, flush with the bottom surface of the needle valve body. Compared to the protruding structure of the prior art, the heat-exposed area in the combustion chamber of this invention is reduced, which can effectively lower the temperature of the second fuel injection orifice, thereby reducing the risk of coking. Simultaneously, the injection cone angle of the second fuel injection orifice should meet a given formula limit to ensure the reliability of the injector.

[0040] Example 2

[0041] In a typical embodiment of this utility model, a dual-fuel engine is provided, including a flat-bottomed dual-fuel injector structure as described in Example 1.

[0042] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A flat-bottomed dual-fuel injector structure, characterized in that, The device includes an injector body, an intermediate body, and a needle valve body connected sequentially from top to bottom. A first fuel needle valve is disposed inside the needle valve body, and a second fuel needle valve is disposed inside the first fuel needle valve. The bottom surface of the first fuel needle valve and the bottom surface of the needle valve body are located on the same plane. The needle valve body is provided with a plurality of first fuel injection holes, and the bottom of the first fuel needle valve is provided with a plurality of second fuel injection holes. The injection cone angle of the second fuel injection holes is less than a set angle.

2. The flat-bottomed dual-fuel injector structure as described in claim 1, characterized in that, A fuel pressure chamber is formed between the bottom of the second fuel needle valve and the bottom of the first fuel needle valve, and the second fuel injection orifice is connected to the fuel pressure chamber.

3. The flat-bottomed dual-fuel injector structure as described in claim 2, characterized in that, The set angle α max The following conditions must be met: α max =arctan[(D2 / 2-A min -D1 / 2) / B min ], where D1 represents the diameter of the second fuel injection orifice, D2 represents the diameter of the outer cylindrical surface at the bottom of the first fuel needle valve, and A min B represents the minimum distance between the second fuel injection orifice and the bottom outer cylindrical surface of the first fuel needle valve. min This indicates the minimum distance between the bottom of the fuel pressure chamber and the lower plane of the first fuel needle valve.

4. The flat-bottomed dual-fuel injector structure as described in claim 3, characterized in that, The minimum distance between the second fuel injection hole and the bottom outer cylindrical surface of the first fuel needle valve is greater than 0.7 mm, and the minimum distance between the bottom of the fuel pressure chamber and the lower plane of the first fuel needle valve is greater than 0.7 mm.

5. The flat-bottomed dual-fuel injector structure as described in claim 1, characterized in that, The injector body, intermediate body, and needle valve body are fastened together by a lower fastening sleeve.

6. The flat-bottomed dual-fuel injector structure as described in claim 1, characterized in that, The top of the injector body is connected to the control body via an upper fastening sleeve. A connector is installed on the top of the control body, and the connector is connected to the injector control circuit.

7. The flat-bottomed dual-fuel injector structure as described in claim 6, characterized in that, The upper part of the injector body has a first fuel inlet, which is connected to a first fuel pipeline. The upper part of the control body has a second fuel inlet, which is connected to a second fuel pipeline.

8. The flat-bottomed dual-fuel injector structure as described in claim 1, characterized in that, A first fuel needle valve spring is disposed above the first fuel needle valve, and a second fuel needle valve spring is disposed above the second fuel needle valve.

9. The flat-bottomed dual-fuel injector structure as described in claim 1, characterized in that, The height of the first fuel injection hole is greater than the height of the second fuel injection hole.

10. A dual-fuel engine, characterized in that, Includes the flat-bottomed dual-fuel injector structure as described in any one of claims 1-9.

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