A dual-fuel injector and dual-fuel engine to prevent end leakage

Abstract

This utility model discloses a dual-fuel injector and a dual-fuel engine for preventing end leakage, including a needle valve body. A fuel A needle valve is disposed inside the needle valve body, and a fuel B needle valve is disposed inside the fuel A needle valve. Multiple annular protrusions are disposed on the bottom surface of the fuel A needle valve near the needle valve body. These annular protrusions increase the heat-receiving area at the bottom of the fuel A needle valve, causing the bottom of the fuel A needle valve to expand upon heating, thus reducing the gap between the bottom of the fuel A needle valve and the needle valve body. This utility model, through the combination of the annular protrusions and the frustum-shaped pressure chamber protrusions, increases the amount of thermal expansion and reduces the gap. It can achieve a dynamic seal between the fuel A needle valve and the needle valve body, allowing the fuel A needle valve to automatically expand and fill the gap when the temperature rises, making it particularly suitable for high-frequency injectors.

Description

Technical Field

[0001] This utility model belongs to the technical field of dual-fuel injectors, specifically relating to a dual-fuel injector and a dual-fuel engine that prevents end leakage. Background Technology

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

[0003] With rapid societal development and increasing energy demand, research into alternative fuels beyond traditional fossil fuels like diesel and gasoline has become a key focus this year. Dual-fuel systems are a hot development trend in the commercial vehicle sector. These systems typically use a small amount of diesel as an ignition source and methanol, natural gas, or other alternative fuels as the primary fuel, offering advantages such as good fuel economy and low emissions.

[0004] In a direct injection dual-fuel supply system, the dual-fuel injector is the most crucial component, enabling timed and quantitative injection control of two fuels. Coaxial dual-fuel injectors are currently considered advanced, with both fuel needle valves arranged coaxially, resulting in a compact and efficient structure. Existing technology discloses a dual-fuel injector and engine, including an injector body, a needle valve body, a methanol needle valve, and a fuel needle valve. Lifting the methanol valve core opens the methanol injection orifice, and lifting the fuel valve core opens the fuel valve core. However, this structure suffers from the following problem: the mating pair between the methanol valve core and the needle valve body typically has a clearance of several micrometers. Figure 6 As shown, when the methanol injection hole is opened, some methanol will leak through the gap, causing abnormal fuel injection at that point, which will lead to a deterioration of the combustion process and affect engine performance and emissions. Utility Model Content

[0005] The purpose of this invention is to provide a dual-fuel injector and dual-fuel engine that prevents end leakage. By increasing the thermal expansion of the needle valve end, the clearance of key mating parts during operation is controlled, thereby reducing the risk of abnormal fuel leakage at the injector end.

[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 dual-fuel injector for preventing end leakage, comprising a needle valve body, wherein a fuel A needle valve is disposed inside the needle valve body, and a fuel B needle valve is disposed inside the fuel A needle valve. Multiple annular protrusions are disposed on the bottom surface of the fuel A needle valve near the needle valve body. The annular protrusions increase the heat-receiving area at the bottom of the fuel A needle valve, causing the bottom of the fuel A needle valve to expand when heated, thereby reducing the gap between the bottom of the fuel A needle valve and the needle valve body.

[0008] As a further technical solution, the multi-layered annular protrusions are arranged sequentially from the outside to the inside with the axis of the fuel A needle valve as the center, and the diameter of the multi-layered annular protrusions decreases sequentially from the outside to the inside.

[0009] As a further technical solution, a pressure chamber protrusion is provided on the bottom surface of the fuel A needle valve. The pressure chamber protrusion is in the shape of an inverted frustum, and the annular protrusion is arranged around the pressure chamber protrusion.

[0010] As a further technical solution, the annular protrusion has a protrusion radius of R, a height of H, and a number of layers of N. The design should satisfy: 4×R×N=(D1-D2) / 2, where D1 represents the diameter of the bottom surface of the fuel A needle valve and D2 represents the diameter of the top of the pressure chamber protrusion.

[0011] As a further technical solution, the height of the annular protrusion is less than or equal to twice the radius of the annular protrusion.

[0012] As a further technical solution, a fuel A channel is formed between the needle valve body and the fuel A needle valve, and a fuel A injection hole is provided on the needle valve body, which is connected to the fuel A channel.

[0013] As a further technical solution, the fuel in the fuel A channel is one of natural gas, methanol, or hydrogen.

[0014] As a further technical solution, a fuel B channel is formed between the fuel A needle valve and the fuel B needle valve, and a fuel B injection hole is provided on the fuel A needle valve, which is connected to the fuel B channel.

[0015] As a further technical solution, the fuel in the fuel B channel is diesel.

[0016] Secondly, embodiments of the present invention provide a dual-fuel engine, including the dual-fuel injector described in the first aspect.

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

[0018] The dual-fuel injector for preventing end leakage provided by this utility model increases the heating area and raises the temperature of the fuel A needle valve by designing multiple annular protrusions on the bottom surface near the gap of the fuel A needle valve. This increases the expansion of the fuel A needle valve, and the multiple annular protrusions are easy to deform under heat. The injector end extends into the engine cylinder and is subjected to high temperature and high pressure. With the temperature of the needle valve body remaining basically unchanged, the temperature of the fuel A needle valve increases and the thermal expansion increases, which reduces the clearance between the fuel A needle valve and the end of the needle valve body, thereby reducing abnormal fuel leakage at this point.

[0019] The dual-fuel injector for preventing end leakage provided by this utility model increases thermal expansion and reduces gaps by setting an annular protrusion in conjunction with a frustum-shaped pressure chamber protrusion; it can achieve dynamic sealing between the fuel A needle valve and the needle valve body, so that the fuel A needle valve automatically expands to fill the gap when the temperature rises, which is especially suitable for injectors with high-frequency operation.

[0020] The dual-fuel injector for preventing end leakage provided by this utility model limits the design parameters of the annular protrusion to precisely control the deformation after thermal expansion, ensuring that the thermal expansion can meet the filling gap requirements; moreover, the protrusion structure is small in size and heats up much faster than the overall structure, enabling dynamic sealing adjustment in the working environment of the fuel injector, thereby achieving a rapid sealing response and preventing end leakage of the injector. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a front view of the dual-fuel injector for preventing end leakage according to this utility model;

[0023] Figure 2 yes Figure 1 A partially enlarged sectional view at point I;

[0024] Figure 3 yes Figure 2 Enlarged view of a section at point II;

[0025] Figure 4 This is a bottom view of the dual-fuel injector for preventing end leakage according to this utility model;

[0026] Figure 5 yes Figure 4 Enlarged view of a section at point III;

[0027] Figure 6 A schematic diagram showing the gap between the methanol valve core and the needle valve body of an existing dual-fuel injector.

[0028] The diagram is for illustrative purposes only.

[0029] Wherein, 1, needle valve body; 2, fuel A needle valve; 3, fuel B needle valve; 4, fuel B channel; 5, fuel A channel; 6, fuel B pressure chamber; 7, fuel A nozzle; 8, fuel B nozzle; 9, annular protrusion; D1, diameter of the mating pair between fuel A needle valve and needle valve body at the end; D2, diameter of the protrusion in fuel B pressure chamber; R, radius of the annular protrusion; H, height of the annular protrusion. Detailed Implementation

[0030] 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.

[0031] Example 1

[0032] In a typical embodiment of this utility model, such as Figure 1-5 As shown, a dual-fuel injector for preventing end leakage is provided, including a needle valve body 1. A fuel A needle valve 2 is disposed inside the needle valve body 1, and a fuel B needle valve 3 is disposed inside the fuel A needle valve 1. Multiple annular protrusions 9 are disposed on the bottom surface of the fuel A needle valve 2 near the needle valve body. The annular protrusions 9 increase the heat-receiving area of ​​the bottom of the fuel A needle valve 2, causing the bottom of the fuel A needle valve to expand when heated, thereby reducing the gap between the bottom of the fuel A needle valve 2 and the needle valve body 1.

[0033] In this embodiment, the multi-layered annular protrusions 9 are arranged sequentially from the outside to the inside with the axis of the fuel A needle valve 1 as the center, and the diameter of the multi-layered annular protrusions 9 decreases sequentially from the outside to the inside.

[0034] In this embodiment, the fuel B pressure chamber 6 and the fuel B nozzle 8 are located at the bottom of the injector. To avoid interference between fuel A and fuel B during injection, a pressure chamber protrusion with a diameter of D2 is present. The bottom surface of the fuel A needle valve 2 is provided with the pressure chamber protrusion, which is in the shape of an inverted frustum. The annular protrusion surrounds the pressure chamber protrusion. Specifically, the diameter of the bottom surface of the fuel A needle valve 2 is larger than the diameter of the pressure chamber protrusion. The pressure chamber protrusion is located at the center of the bottom surface of the fuel A needle valve and is coaxially arranged with the fuel A needle valve. Due to the presence of the fuel B pressure chamber, the height of the pressure chamber protrusion is relatively high, much greater than the height of the annular protrusion.

[0035] In this embodiment, the radius of the annular protrusion is R, the height is H, and the number of layers is N. The design should satisfy: 4×R×N=(D1-D2) / 2, where D1 represents the diameter of the bottom surface of the fuel A needle valve, D2 represents the diameter of the top of the pressure chamber protrusion, the height of the annular protrusion is less than or equal to twice the radius of the annular protrusion, and H≤2×R.

[0036] In this embodiment, a fuel A channel 5 is formed between the needle valve body 1 and the fuel A needle valve 2, and a fuel A injection hole 7 is provided on the needle valve body 1, which is connected to the fuel A channel 5.

[0037] Optionally, the fuel in the fuel A channel is one of natural gas, methanol, or hydrogen.

[0038] In this embodiment, a fuel B channel 4 is formed between the fuel A needle valve 2 and the fuel B needle valve 3, and a fuel B injection hole 8 is provided on the fuel A needle valve 2, which is connected to the fuel B channel 4.

[0039] Optionally, the fuel in fuel channel B 4 is diesel.

[0040] The working principle of the dual-fuel injector provided in this embodiment is as follows:

[0041] When the needle valve body 1 is fixed, and the fuel A needle valve 2 moves upward, the fuel A injection hole 7 located at the end of the needle valve body 1 opens, and fuel A reaches the fuel A injection hole 7 through the fuel A channel 5 and is injected out.

[0042] With fuel B needle valve 3 closed, the ends of fuel A needle valve 2 and fuel B needle valve 3 form fuel B pressure chamber 6. When fuel B needle valve 3 moves upward, fuel B injection hole 8 located at the end of fuel A needle valve 2 opens, and fuel B reaches fuel B injection hole 8 through fuel B channel 4 and is injected.

[0043] The injector tip extends into the engine cylinder and is subjected to high temperature and pressure. Under the influence of high temperature, both the needle valve body 1 and the fuel A needle valve 2 undergo thermal expansion, resulting in a change in the clearance of the mating pair at D1. By designing multiple annular protrusions on the bottom surface of the fuel A needle valve 2 near the clearance, the heat-receiving area is increased, raising the temperature of the fuel A needle valve 2 and thus increasing the expansion amount of the fuel A needle valve 2. At the same time, the multi-layered annular protrusions are easily deformed by heat.

[0044] Because the temperature of fuel A needle valve 2 is higher than that of needle valve body 1, and an annular protrusion structure is added, the thermal expansion of fuel A needle valve 2 is greater than that of needle valve body 1. This reduces the clearance between the mating pair of fuel A needle valve 2 and needle valve body 1, thereby reducing abnormal fuel leakage at this location.

[0045] Example 2

[0046] In a typical embodiment of the utility model, a dual-fuel engine is provided, including a dual-fuel injector as described in Example 1.

[0047] 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 dual-fuel injector for preventing end leakage, characterized in that, The device includes a needle valve body, inside which a fuel A needle valve is disposed, and inside which a fuel B needle valve is disposed, and the bottom surface of the fuel A needle valve is provided with multiple layers of annular protrusions near the needle valve body. The annular protrusions increase the heat-receiving area at the bottom of the fuel A needle valve, causing the bottom of the fuel A needle valve to expand when heated, thereby reducing the gap between the bottom of the fuel A needle valve and the needle valve body.

2. The dual-fuel injector for preventing end leakage as described in claim 1, characterized in that, The multi-layered annular protrusions are arranged sequentially from the outside to the inside with the axis of the fuel A needle valve as the center, and the diameter of the multi-layered annular protrusions decreases sequentially from the outside to the inside.

3. The dual-fuel injector for preventing end leakage as described in claim 1, characterized in that, The bottom surface of the fuel A needle valve is provided with a pressure chamber protrusion, which is in the shape of an inverted frustum, and the annular protrusion is arranged around the pressure chamber protrusion.

4. The dual-fuel injector for preventing end leakage as described in claim 3, characterized in that, The annular protrusion has a radius of R, a height of H, and a number of layers of N. The design should satisfy: 4×R×N=(D1-D2) / 2, where D1 represents the diameter of the bottom surface of the fuel A needle valve and D2 represents the diameter of the top of the pressure chamber protrusion.

5. The dual-fuel injector for preventing end leakage as described in claim 1, characterized in that, The height of the annular protrusion is less than or equal to twice the radius of the annular protrusion.

6. The dual-fuel injector for preventing end leakage as described in claim 1, characterized in that, A fuel A channel is formed between the needle valve body and the fuel A needle valve. A fuel A injection hole is provided on the needle valve body, and the fuel A injection hole is connected to the fuel A channel.

7. The dual-fuel injector for preventing end leakage as described in claim 6, characterized in that, The fuel in the fuel A channel is one of natural gas, methanol, or hydrogen.

8. The dual-fuel injector for preventing end leakage as described in claim 1, characterized in that, A fuel B channel is formed between the fuel A needle valve and the fuel B needle valve. The fuel A needle valve is provided with a fuel B injection hole, which is connected to the fuel B channel.

9. The dual-fuel injector for preventing end leakage as described in claim 8, characterized in that, The fuel in the fuel B channel is diesel.

10. A dual-fuel engine comprising a dual-fuel injector as claimed in any one of claims 1-9.

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