Structure for slowing down fuel interpenetration of dual-fuel injector
By setting a fuel check groove in the dual-fuel injector, the problem of fuel ratio imbalance caused by fuel infiltration is solved, stable fuel ratio injection is achieved, and abnormal combustion is avoided.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WEICHAI POWER CO LTD
- Filing Date
- 2025-06-13
- Publication Date
- 2026-04-21
AI Technical Summary
In existing dual-fuel injectors, the fuels permeate each other through the mating gap, leading to an imbalance in the fuel ratio and causing abnormal combustion phenomena such as misfire, poor emissions, and unstable detonation pressure.
Multiple fuel check grooves, including fuel A check groove and fuel B check groove, are set between fuel B ring cavity and fuel A ring cavity. The groove opening direction and position are designed to prevent fuel flow and reduce mixing between fuels.
It effectively reduces the amount of fuel mixing, avoids fuel ratio imbalance, and prevents abnormal combustion phenomena such as misfire, poor emissions, and unstable explosion pressure.
Smart Images
Figure CN224149706U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of dual-fuel injectors, specifically relating to a structure that reduces the mutual penetration of fuels in dual-fuel injectors. Background Technology
[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.
[0003] In existing internal combustion engines, fuel injectors inject fuel into the combustion chamber of the cylinder to provide power. However, with rapid societal development and increasing energy demands, there is a need to seek alternative fuels beyond traditional fossil fuels such as diesel and gasoline.
[0004] In recent years, internal combustion engines have adopted direct injection dual-fuel supply systems, with the dual-fuel injector being one of the most important components. Dual-fuel injectors use a small amount of diesel fuel as an ignition source and alternative fuels such as methanol or natural gas as the primary fuel; they offer advantages such as good fuel economy and low emissions.
[0005] The prior art discloses a dual-fuel injector and its working method. In this scheme, the injector needle valves of the two fuels are integrated into a whole by nesting. The injector includes a diesel control chamber and a second fuel control chamber. The diesel control chamber or the second fuel control chamber can be controlled by controlling the opening or closing of the diesel control chamber or the second fuel control chamber.
[0006] However, in the above scheme, the injector needle valves for the two fuels are connected in a nested manner, with the valve bodies sliding between each other. A certain clearance exists between the valve bodies, allowing communication between the annular cavities at the ends of the diesel control chamber and the second fuel chamber, as well as between the annular cavities at the ends of the diesel and second fuel chambers, through this clearance. Therefore, when the pressure in the diesel control chamber or the diesel chamber is too high, diesel fuel will flow through the clearance into the annular cavity at the end of the second fuel chamber, causing diesel fuel to mix into the second fuel. Similarly, when the pressure in the second fuel is too high, the second fuel will flow through the clearance into the diesel control chamber or the diesel chamber, causing the second fuel to mix into the diesel fuel.
[0007] In practical applications, such as when the first fuel is a gaseous fuel like hydrogen or natural gas, and the second fuel is a liquid fuel like diesel, air bubbles can be observed in the return line of the second fuel. If this is not controlled or mitigated, once the amount of the first fuel mixed with the second fuel reaches a certain level, it will affect the originally set ratio of the first and second fuels injected into the internal combustion engine cylinder; this will further lead to abnormal combustion phenomena such as misfire (non-combustion), poor emissions, and unstable knock pressure. Summary of the Invention
[0008] To address the aforementioned problems, this invention provides a structure that mitigates the interpenetration of fuels in a dual-fuel injector. By setting multiple fuel check grooves between the fuel B annular cavity and the fuel A annular cavity, the flow of either fuel A or fuel B to the fuel B annular cavity or the fuel A annular cavity is slowed down, thereby reducing the amount of fuel mixing in the dual-fuel injector and preventing abnormal combustion phenomena such as misfire (non-combustion), poor emissions, and unstable detonation pressure in the internal combustion engine cylinder.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] A structure for mitigating fuel cross-penetration in a dual-fuel injector is provided inside the dual-fuel injector, which includes a needle valve body, a fuel A needle valve slidably disposed inside the needle valve body, and a fuel B needle valve slidably disposed inside the fuel A needle valve.
[0011] Multiple annular cavities are designed between the fuel A needle valve and the needle valve body. The upper annular cavity is the fuel B annular cavity, and the lower annular cavity is the fuel A annular cavity.
[0012] The structure that mitigates fuel cross-penetration in dual-fuel injectors includes multiple fuel check grooves located between the fuel B annular cavity and the fuel A annular cavity.
[0013] Preferably, the fuel check trough includes two types: one is a fuel A check trough, and the other is a fuel B check trough; the fuel A check trough and the fuel B check trough have the same shape and size.
[0014] Preferably, the fuel A check groove is provided on the needle valve body, with the groove opening facing the fuel A needle valve side and the opening facing downward.
[0015] Preferably, the fuel B check groove is provided on the fuel A needle valve, with the groove opening facing the needle valve body and the opening facing upward.
[0016] Preferably, the radius of the fuel check groove is R, and the radius R needs to satisfy: 0.2mm≤R≤0.5*the smaller of the wall thickness of the needle valve body and the fuel A needle valve.
[0017] Preferably, the depth of the fuel check valve is H, and the depth H needs to satisfy: H≥0.8R.
[0018] Preferably, the opening length of the fuel check valve is L, and the opening length L needs to satisfy: 1.2R≤L≤2R.
[0019] Preferably, the opening angle of the fuel check valve is α, and the opening angle α needs to satisfy: 30°≤α≤60°.
[0020] Preferably, the fuel A annular cavity is connected to the fuel A channel, and the fuel B annular cavity is connected to the fuel B channel.
[0021] Preferably, the bottom circumferential direction of the dual-fuel injector is uniformly provided with a plurality of fuel A injection holes and a plurality of fuel B injection holes, wherein the fuel A injection holes are located at the bottom end of the needle valve body, and the fuel B injection holes are located at the bottom end of the fuel A needle valve.
[0022] Compared with the prior art, the advantages and positive effects of this invention are:
[0023] This invention incorporates multiple fuel check grooves between the fuel B annular cavity and the fuel A annular cavity. The fuel A check groove is located on the needle valve body, with its opening facing downwards towards the fuel A needle valve. The fuel B check groove is located on the fuel A needle valve, with its opening facing upwards towards the needle valve body. When fuel A or fuel B flows into the fuel B annular cavity or the fuel A annular cavity under pressure, a portion of fuel A or fuel B flows into the fuel B check groove or the fuel A check groove, changing its flow direction and preventing other vertically flowing fuel A or fuel B from entering. This slows down the flow of fuel A or fuel B into the fuel B annular cavity or the fuel A annular cavity, reducing the amount of fuel mixing in the dual-fuel injector and preventing abnormal combustion phenomena such as misfire (non-combustion), poor emissions, and unstable detonation pressure in the internal combustion engine cylinder. Attached Figure Description
[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0025] Figure 1 This is a front view of the dual-fuel injector according to an embodiment of the present invention;
[0026] Figure 2 This is an enlarged bottom view of the dual-fuel injector according to an embodiment of the present invention;
[0027] Figure 3 This is an embodiment of the present utility model. Figure 1 Cross-sectional view at point I;
[0028] Figure 4 This is an embodiment of the present utility model. Figure 3Enlarged view at point II;
[0029] In the picture:
[0030] 1. Needle valve body; 1-1. Fuel A check groove; 2. Fuel A needle valve; 2-1. Fuel B check groove; 3. Fuel B needle valve; 4. Fuel B ring cavity; 5. Fuel A ring cavity. Detailed Implementation
[0031] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0032] The present invention will now be described in detail with reference to the accompanying drawings. This embodiment discloses a structure for mitigating fuel cross-penetration in a dual-fuel injector, which is disposed inside the dual-fuel injector. Specifically, as shown in the accompanying drawings... Figure 1 , Figure 3 As shown, the dual-fuel injector includes a needle valve body 1, a fuel A needle valve 2 slidably disposed within the needle valve body 1, and a fuel B needle valve 3 slidably disposed within the fuel A needle valve 2. It should be noted that, similar to the prior art, in order to ensure the relative sliding between the needle valve body 1 and the fuel A needle valve 2, and the relative sliding between the fuel A needle valve 2 and the fuel B needle valve 3, there is a certain fitting clearance between the needle valve body 1 and the fuel A needle valve 2, and there is also a certain fitting clearance between the fuel A needle valve 2 and the fuel B needle valve 3.
[0033] like Figure 3 As shown, multiple annular cavities are designed between the fuel A needle valve 2 and the needle valve body 1. The upper annular cavity is the fuel B annular cavity 4, which is filled with fuel B; while the lower annular cavity is the fuel A annular cavity 5, which is filled with fuel A.
[0034] It should be noted that fuel A annular cavity 5 is connected to fuel A channel, which is used to supply fuel A to fuel A annular cavity 5; fuel B annular cavity 4 is connected to fuel B channel, which is used to supply fuel B to fuel B annular cavity 4.
[0035] like Figure 1 , Figure 2 As shown, the bottom circumference of the dual-fuel injector is uniformly provided with several fuel A injection holes and several fuel B injection holes. The fuel A injection holes are located at the bottom end of the needle valve body 1, and the fuel B injection holes are located at the bottom end of the fuel A needle valve 2. The fuel A injection holes are used to inject fuel A, and the fuel B injection holes are used to inject fuel B. It should be noted that the number of fuel A injection holes and fuel B injection holes is set according to actual conditions.
[0036] Furthermore, such as Figure 3As shown, fuel B needle valve 3 has an inclined groove, and above the inclined groove is an annular groove, meaning the annular groove and the inclined groove are always in communication. Furthermore, the annular groove is connected to the fuel B annular cavity 4, which can be achieved by opening one or more through holes on the side wall of fuel A needle valve 2, allowing the fuel B annular cavity 4 to communicate with the annular groove. Even further, the bottom of the inclined groove is always in communication with the gap between fuel B needle valve 3 and fuel A needle valve 2. It should be noted that when fuel B needle valve 3 moves upward, the gap between fuel B needle valve 3 and fuel A needle valve 2 can connect to the fuel B injection orifice; when fuel B needle valve 3 returns to its original position downward, the bottom of fuel B needle valve 3 blocks the fuel B injection orifice, and the gap between fuel B needle valve 3 and fuel A needle valve 2 is disconnected from the fuel B injection orifice.
[0037] Furthermore, such as Figure 3 As shown, when needle valve body 1 is fixed, fuel A needle valve 2 moves upward, and fuel B needle valve 3 is stationary relative to fuel A needle valve 2, as follows: Figure 3 As shown, the gap between the fuel A annular cavity 5 and the needle valve body 1 and fuel A needle valve 2 is connected. The gap between the needle valve body 1 and fuel A needle valve 2 is connected to the fuel A injection hole. Under pressure, fuel A in the fuel A annular cavity 5 flows downward and is ejected from the fuel A injection hole. When the fuel A needle valve 2 resets, the fuel A annular cavity 5 is no longer connected to the fuel A injection hole.
[0038] Furthermore, when needle valve body 1 and fuel A needle valve 2 are fixed, while fuel B needle valve 3 moves downward, the fuel B annular cavity 4 and fuel B injection orifice will connect. Under pressure, fuel B in the fuel B annular cavity 4 flows downward and is ejected from the fuel B injection orifice. When fuel B needle valve 3 resets, the connection between fuel B annular cavity 4 and fuel B injection orifice is broken.
[0039] In this embodiment, fuel A can be a gaseous fuel such as natural gas, methanol, or hydrogen, and fuel B is diesel.
[0040] The structure that mitigates fuel cross-mixing in dual-fuel injectors includes multiple fuel check grooves. Specifically, multiple fuel check grooves are provided between fuel B annular cavity 4 and fuel A annular cavity 5. By providing multiple fuel check grooves, the phenomenon that fuel A and fuel B will mix under the action of pressure difference is mitigated.
[0041] Specifically, such as Figure 4 As shown, there are two types of fuel check channels: fuel A check channel 1-1 and fuel B check channel 2-1. In this embodiment, fuel A check channel 1-1 and fuel B check channel 2-1 have the same shape and size; they are divided into fuel A check channel 1-1 and fuel B check channel 2-1 according to their location and opening direction.
[0042] The difference between fuel A check groove 1-1 and fuel B check groove 2-1 is that fuel A check groove 1-1 is set on the needle valve body 1, circumferentially along the inner wall of the needle valve body 1, with the groove opening facing the fuel A needle valve 2 side and the opening facing downwards; fuel B check groove 2-1 is set on the fuel A needle valve 2, circumferentially along the outer wall of the fuel A needle valve 2, with the groove opening facing the needle valve body 1 side and the opening facing upwards.
[0043] like Figure 3 , Figure 4 As shown, multiple fuel A check grooves 1-1 are provided on the needle valve body 1, with the groove openings facing the fuel A needle valve 2 side and downwards. When there is a pressure difference between the fuel B annular cavity 4 and the fuel A annular cavity 5, and the pressure in the fuel A annular cavity 5 is greater than the pressure in the fuel B annular cavity 4, the fuel A inside the fuel A annular cavity 5 will flow upwards along the fitting gap between the needle valve body 1 and the fuel A needle valve 2, and then pass through the multiple fuel A check grooves 1-1.
[0044] like Figure 4 As shown, when fuel A flows upward along the fitting gap between the needle valve body 1 and the fuel A needle valve 2 under the action of pressure difference, when it flows through the fuel A check groove 1-1, part of the fuel A will flow vertically upward, while part of the fuel A will enter the fuel A check groove 1-1.
[0045] like Figure 4 As shown, a portion of fuel A entering the fuel A check valve 1-1 will flow upwards along the arc-shaped inner wall of the fuel A check valve 1-1, and will be gradually guided to change its flow direction, eventually flowing downwards in the opposite direction at the upper end of the fuel A check valve 1-1, as... Figure 4 The arrow in fuel A check valve 1-1 indicates this.
[0046] It should be explained that when some fuel A flows downwards in the reverse direction at the upper end of the fuel A non-return groove 1-1, the downward-flowing fuel A will collide with the normally upward-flowing fuel A within the fuel A non-return groove 1-1, weakening the upward-flowing tendency of the upward-flowing fuel A. By setting multiple fuel A non-return grooves 1-1 between the fuel A annular cavity 5 and the fuel B annular cavity 4, the process of fuel A flowing upwards into the fuel B annular cavity 4 can be slowed down; thereby reducing the amount of fuel A flowing into the fuel B annular cavity 4.
[0047] By setting multiple fuel A check troughs 1-1, the flow of fuel A into the fuel B annular cavity 4 is controlled and slowed down, reducing the amount of fuel A flowing into the fuel B annular cavity 4 and reducing the amount of fuel A in fuel B. Since the amount of fuel A in fuel B is small, after it is injected into the internal combustion engine cylinder separately from fuel A, the ratio of fuel B to fuel A will not exceed the set ratio. Therefore, the mixed fuel will not cause abnormal combustion phenomena such as misfire (non-combustion), poor emissions, or unstable knock pressure in the internal combustion engine cylinder.
[0048] Furthermore, such as Figure 3 , Figure 4 As shown, multiple fuel B check grooves 2-1 are installed on the fuel A needle valve 2, with the groove openings facing the needle valve body 1 and upwards. When there is a pressure difference between the fuel B annular cavity 4 and the fuel A annular cavity 5, and the pressure in the fuel A annular cavity 5 is less than the pressure in the fuel B annular cavity 4, the fuel B inside the fuel B annular cavity 4 will flow downwards along the fitting gap between the needle valve body 1 and the fuel A needle valve 2, and then pass through the multiple fuel B check grooves 2-1.
[0049] like Figure 4 As shown, when fuel B flows upward along the fitting gap between the needle valve body 1 and the fuel A needle valve 2 under the action of pressure difference, when it flows through the fuel B check groove 2-1, part of the fuel B will flow vertically downward, while part of the fuel B will enter the fuel B check groove 2-1.
[0050] like Figure 4 As shown, a portion of fuel B entering the fuel B check trough 2-1 flows downwards along the arc-shaped inner wall of the fuel B check trough 2-1, and is gradually guided to change its flow direction, eventually flowing upwards in the opposite direction at the lower end of the fuel B check trough 2-1, as... Figure 4 The arrow in fuel B check valve 2-1 is shown.
[0051] It should be explained that when some fuel B flows upward in the reverse direction at the lower end of the fuel B check groove 2-1, the upward-flowing fuel B will collide with the normally downward-flowing fuel B in the fuel B check groove 2-1, which weakens the downward-flowing trend of fuel B. By setting multiple fuel B check grooves 2-1 between the fuel A annular cavity 5 and the fuel B annular cavity 4, the process of fuel B flowing downward into the fuel A annular cavity 5 can be slowed down; thereby reducing the amount of fuel B flowing into the fuel A annular cavity 5.
[0052] By setting multiple fuel B check troughs 2-1, the inflow of fuel B into the fuel A annular cavity 5 is controlled and slowed down, reducing the amount of fuel B flowing into the fuel A annular cavity 5 and thus reducing the amount of fuel B in fuel A. When fuel A mixed with fuel B is injected separately into the internal combustion engine cylinder, because the amount of fuel B in fuel A is small, the ratio of fuel B to fuel A cannot exceed the set ratio. Therefore, abnormal combustion phenomena such as misfire (non-combustion), poor emissions, and unstable knock pressure in the internal combustion engine cylinder can be avoided.
[0053] Furthermore, by controlling and reducing the amount of fuel B mixed in fuel A, and simultaneously controlling and reducing the amount of fuel A mixed in fuel B, the amount of fuel A and fuel B injected into the internal combustion engine cylinder will be prevented from exceeding the set ratio, thus preventing abnormal combustion phenomena such as misfire (non-combustion), poor emissions, and unstable knock pressure in the internal combustion engine cylinder.
[0054] like Figure 4 As shown, in this embodiment, to ensure that the fuel B check valve 2-1 or the fuel A check valve 1-1 can allow a portion of fuel B or a portion of fuel A to flow within it and can change the flow direction, the dimensions of the fuel B check valve 2-1 or the fuel A check valve 1-1 need to meet the following conditions:
[0055] 1. The radius of fuel B check groove 2-1 or fuel A check groove 1-1 is R. The radius R needs to satisfy: 0.2mm≤R≤0.5*the smaller of the wall thicknesses on both sides of the fuel check groove location (i.e., the smaller of the wall thicknesses of needle valve body 1 and fuel A needle valve).
[0056] 2. The depth of fuel B check valve 2-1 or fuel A check valve 1-1 is H, and the depth H needs to satisfy: H≥0.8R;
[0057] 3. The opening length of fuel B check valve 2-1 or fuel A check valve 1-1 is L, and the opening length L needs to satisfy: 1.2R≤L≤2R;
[0058] 4. The opening angle of fuel B check valve 2-1 or fuel A check valve 1-1 is α, and the opening angle α needs to satisfy: 30°≤α≤60°.
[0059] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.
Claims
1. A structure for mitigating fuel cross-penetration in a dual-fuel injector, disposed inside the dual-fuel injector, the dual-fuel injector comprising a needle valve body, wherein a fuel A needle valve is slidably disposed within the needle valve body, and a fuel B needle valve is slidably disposed within the fuel A needle valve; characterized in that, Multiple annular cavities are designed between the fuel A needle valve and the needle valve body. The upper annular cavity is the fuel B annular cavity, and the lower annular cavity is the fuel A annular cavity. The structure that mitigates fuel cross-penetration in dual-fuel injectors includes multiple fuel check grooves located between the fuel B annular cavity and the fuel A annular cavity.
2. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 1, characterized in that, The fuel check trough includes two types: one is the fuel A check trough, and the other is the fuel B check trough; the fuel A check trough and the fuel B check trough have the same shape and size.
3. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 2, characterized in that, The fuel A check groove is provided on the needle valve body, with the groove opening facing the fuel A needle valve side and the opening facing downwards.
4. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 2, characterized by The fuel B check groove is installed on the fuel A needle valve, with the groove opening facing the side of the needle valve body and the opening facing upwards.
5. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 1, wherein The radius of the fuel check groove is R, and the radius R needs to satisfy: 0.2mm≤R≤0.5*the smaller of the wall thickness of the needle valve body and the fuel A needle valve.
6. The structure for mitigating fuel interpenetration in a dual-fuel injector as described in claim 1, characterized in that, The depth of the fuel check valve is H, and the depth H needs to satisfy: H≥0.8R.
7. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 1, wherein The opening length of the fuel check valve is L, and the opening length L needs to satisfy: 1.2R≤L≤2R.
8. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 1, wherein The opening angle of the fuel check valve is α, and the opening angle α needs to satisfy: 30°≤α≤60°.
9. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 1, wherein The fuel A annular cavity is connected to the fuel A channel, and the fuel B annular cavity is connected to the fuel B channel.
10. A structure for reducing mutual penetration of fuels in a dual fuel injector according to claim 1, wherein The bottom circumferential direction of the dual-fuel injector is uniformly provided with a number of fuel A injection holes and a number of fuel B injection holes, wherein the fuel A injection holes are located at the bottom end of the needle valve body, and the fuel B injection holes are located at the bottom end of the fuel A needle valve.