Fuel filler pipe assembly with restriction

Abstract

This invention discloses a refueling pipe assembly with a throttling structure in the field of automotive fuel supply system technology. The assembly includes a refueling pipe and a circulation pipe. The circulation pipe has a throttling structure, which is a locally extruded deformation portion formed on the side wall of the circulation pipe. This deformation portion protrudes inward, forming a throttling orifice with a concave lens-shaped cross-section on the inner side of the pipe wall. An arc-shaped buffer section is provided between the throttling orifice and the outlet end of the circulation pipe. This invention can reduce refueling noise, simplify the throttling orifice process, and improve the reliability of the ORVR system.

Description

Technical Field

[0001] This invention relates to the field of automotive fuel supply system technology, and in particular to a fuel filler pipe assembly with a throttling structure. Background Technology

[0002] During vehicle refueling, the recovery of fuel vapors is crucial for environmental protection. Currently, vehicles equipped with Onboard Vapor Regeneration (ORVR) systems typically use a recirculation pipe with a flow-limiting structure. One end of this recirculation pipe is connected to the fuel tank, and the other end leads to the refueling line. The flow of fuel creates a negative pressure at the outlet of the recirculation pipe, drawing fuel vapors from the fuel tank back into the refueling line and returning them to the fuel tank.

[0003] Common flow-limiting structures (throttling orifices) are located at the end of the circulation pipe, and are formed into a reduced diameter through mechanical processing such as heading or cutting. For example, the prior art discloses a high-efficiency oil vapor recovery refueling pipe, publication number: CN212685233U; application date: 2020-08-04; it includes a refueling pipe, a guide orifice, and a circulation pipe. The outlet of the circulation pipe penetrates the upper sidewall of the refueling pipe, connecting the circulation pipe to the refueling pipe. The opening of the circulation pipe extending into the refueling pipe is a constricted section with an opening area smaller than the cross-sectional area of ​​the refueling pipe's orifice. The outlet of the circulation pipe is modified to a constricted section based on the working capacity of the carbon canister. The specific dimensions are designed according to the carbon canister specifications. When the carbon canister's working capacity is large, the constriction is large (i.e., the outlet area is small), and vice versa. This ensures that the flow rate of oil vapor at the circulation pipe outlet matches the working capacity of the carbon canister, precisely controlling the amount of oil vapor volatilization. Its shortcomings are as follows: First, the fuel flow velocity changes drastically at the throttling orifice where the pipe suddenly contracts, generating strong turbulence and airflow disturbance, resulting in a significant increase in refueling noise; Second, the circulation pipe generally uses a pipe with an outer diameter of 8mm and an inner diameter of 6.22mm. To achieve the pipe constriction, multiple processes such as end milling and cutting are required, making the process complex. Moreover, the dimensional accuracy of the throttling orifice diameter (usually Φ2.8-3.2mm) is not easy to control, resulting in a low yield rate; Finally, the small throttling orifice exposed at the pipe end is very easy to be blocked by foreign objects during assembly or use, causing the ORVR function to fail. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a refueling pipe assembly with a throttling structure, which can reduce refueling noise, simplify the throttling process, and improve the reliability of the ORVR system.

[0005] The objective of this invention is achieved as follows: a refueling pipe assembly with a throttling structure, comprising a refueling pipe and a circulation pipe, wherein the circulation pipe is provided with a throttling structure, the throttling structure being a locally extruded deformation portion formed on the side wall of the circulation pipe, the deformation portion protruding into the pipe to form a throttling orifice with a concave lens-shaped cross-section on the inner side of the pipe wall; an arc-shaped buffer section is provided between the throttling orifice and the air outlet end of the circulation pipe.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The arc-shaped protrusion of the concave lens-shaped throttling orifice can guide the liquid flow along the tangential direction of the pipe wall, reducing the generation of eddies. By moving the throttling orifice from the pipe end to the side wall of the pipe body and keeping a sufficiently long flow channel downstream, the turbulence generated after the fuel flows through the throttling orifice can be effectively buffered and attenuated in the pipe, avoiding direct bursts at the pipe opening. Under the same refueling flow rate, the present invention can significantly reduce airflow noise compared with the traditional end throttling structure; (2) The tooling of radial clamping is used for one-time extrusion molding, replacing the traditional multiple processes such as heading, cutting, and deburring. This process can accurately control the width of the clamp-shaped throttling orifice, greatly improving product consistency and yield; (3) The throttling orifice is embedded in the inner side of the pipe wall, and the pipe body itself provides physical shielding for it, effectively avoiding direct impact and blockage of external foreign objects (such as assembly residue and dust), and improving the working reliability of the ORVR system.

[0007] As a further improvement of the invention, the width H of the throttling orifice at its narrowest point is 2.6 mm to 2.9 mm. This represents the optimal balance between the "throttling effect" and "flow capacity" of the circulation pipe. The concave lens shape guides the fluid through a smooth transition, significantly reducing eddies and turbulence caused by throttling compared to abrupt diameter reduction, thereby minimizing irreversible pressure loss.

[0008] As a further improvement of the present invention, the throttling orifice is formed in one step by radially clamping and extruding the wall of the circulation pipe. The throttling structure is integral with the circulation pipe body, without any welds, adhesive seams or mechanical connection points, eliminating the risk of fuel leakage, corrosion cracking or fatigue failure that may be caused by stress concentration due to the connection or assembly of different materials, and greatly improving the service life under long-term vibration, fuel immersion and temperature cycling conditions.

[0009] As a further improvement of the present invention, the length of the arc-shaped buffer section is 8 to 10 times the inner diameter of the circulation pipe. This length of 8 to 10 times the inner diameter ensures that the fuel vapor has sufficient distance for efficient energy conversion during the turning process, maximizing the smooth conversion of the kinetic energy of the high-speed fuel vapor after throttling into pressure energy, thereby significantly reducing overall flow resistance and irreversible pressure loss.

[0010] As a further improvement of the present invention, the refueling pipe includes a refueling cup, a main refueling pipe, and a refueling hose arranged sequentially; the outlet end of the circulation pipe is a straight pipe with a flat end structure, and penetrates the flared section sidewall of the main refueling pipe, so that the circulation pipe is connected to the refueling pipe; a raised ring is provided at the root of the connection between the circulation pipe and the refueling pipe, and the lower side of the raised ring is welded and fixed to the flared section sidewall of the main refueling pipe. The raised ring acts as a mechanical limiting structure to ensure that the depth of the circulation pipe inserted into the main refueling pipe is accurate and consistent, preventing it from being pushed in too deeply or pulled out during welding or use.

[0011] As a further improvement of the present invention, it also includes a desorption pipe and a vent pipe; several first supports are arranged at intervals on the outer side of the bent section of the main filling pipe and the circulation pipe; a second support is arranged on the outer side of the flared section of the main filling pipe; several fixing clamps are sleeved on the desorption pipe and the vent pipe, and the fixing clamps are arranged one-to-one with the first supports and form a locking structure with the corresponding first supports; a limiting structure is provided on the second support to restrict the circumferential rotation of the refueling pipe. The desorption pipe, the vent pipe and the core main filling pipe and the circulation pipe are formed into a rigid fixing system through the supports, which avoids relative friction and collision between the pipes caused by vibration, which not only prevents pipe wear and breakage, but also eliminates possible abnormal noises in the vehicle, thus improving the overall quality of the vehicle.

[0012] As a further improvement of the present invention, the first bracket includes a small arc-shaped portion, a large arc-shaped portion, and a straight plate portion integrally connected. The inner wall of the small arc-shaped portion is fixedly connected to the outer periphery of the circulation pipe, and the large arc-shaped portion is fixedly connected to the outer periphery of the refueling pipe. The straight plate portion has a fixing hole for engaging with the fixing clamp. The double arc-shaped portions simultaneously fix the circulation pipe and the refueling pipe, which is equivalent to putting a "combined shock absorber" on them, effectively canceling the transmission of vibration between them and protecting the internal precision structure. The fixing clamp is pre-matched with the fixing hole of the first bracket. During final assembly, the clamp only needs to be inserted into the fixing hole to complete the fixing of the desorption pipe and the vent pipe, which greatly improves the assembly efficiency.

[0013] As a further improvement of the present invention, the fixing clamp is an integrally formed structural component, including a first clamp portion, a second clamp portion, a connecting bridge portion, and a locking portion; the first clamp portion is used to clamp the desorption pipe; the second clamp portion is used to clamp the desorption vent pipe; the connecting bridge portion integrally connects the first clamp portion and the second clamp portion, so that the two maintain a predetermined relative position; the locking portion integrally connects the first clamp portion, and is used to form a detachable locking connection with the corresponding first bracket. The rigid connection of the connecting bridge portion fixes the relative position of the desorption pipe and the vent pipe, avoiding mutual collision or displacement of the two pipes during vibration, and protecting the integrity of the pipes.

[0014] As a further improvement of the present invention, the second clamp part is an open C-shaped structure, with an L-shaped elastic latch on one side for elastically clamping the pipeline, and a T-shaped groove on the other side for engaging with the elastic latch, forming an elastic self-locking clamping mechanism; the engaging part includes a triangular elastic hook and an arc-shaped limiting plate; the end of the elastic hook is open and has a stepped barb; the first bracket has a rectangular locking hole that engages with the elastic hook, forming an elastic plug-in locking structure. The rectangular locking hole only allows the triangular hook to be inserted at the only correct angle, and its long side and short side respectively restrict the forward and backward movement and left and right swaying of the hook, ensuring the relative position of the fixed pipe clamp and the first bracket, thereby ensuring the arrangement accuracy of the desorption pipe and the vent pipe.

[0015] As a further improvement of the present invention, the limiting structure is a protrusion or a snap-fit ​​that mates with a mounting hole on the vehicle body sheet metal. High-frequency vibrations during vehicle operation generate torsional loads, and the mechanical interlocking structure formed by the protrusion / snap-fit ​​and the mounting hole can resist these loads, preventing loosening or repositioning after prolonged use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0018] Figure 2 This is a three-dimensional structural diagram of the first support in this invention.

[0019] Figure 3 This is a three-dimensional structural diagram of the second support in this invention.

[0020] Figure 4 This is a three-dimensional structural diagram of the fixing clamp in this invention.

[0021] Figure 5 This is a three-dimensional structural diagram of the throttling structure in this invention.

[0022] Figure 6 This is a cross-sectional view of the throttling structure in this invention.

[0023] Among them, 1 is the refueling pipe, 2 is the circulation pipe, 201 is the throttling structure, 202 is the arc-shaped buffer section, 3 is the desorption pipe, 4 is the vent pipe, 5 is the first bracket, 501 is the small arc-shaped part, 502 is the large arc-shaped part, 503 is the straight plate part, 503a is the card hole, 6 is the second bracket, 601 is the protrusion, 7 is the body sheet metal, 8 is the fixing pipe clamp, 801 is the first pipe clamp part, 802 is the second pipe clamp part, 802a is the card tongue, 802b is the groove, 803 is the connecting bridge part, 804 is the engaging part, 804a is the card hook, 804b is the limiting plate, and 804c is the barb. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 The illustrated fuel filler assembly with a throttling structure includes a fuel filler pipe 1, a circulation pipe 2, a desorption pipe 3, and a vent pipe 4. The fuel filler pipe 1 includes a fuel filler cup, a main filling pipe, and a filling hose connected in sequence. The outlet end of the circulation pipe 2 has a straight, flat-mouth structure and penetrates the flared section sidewall of the main filling pipe, thus connecting the circulation pipe 2 and the fuel filler pipe 1. A raised ring is provided at the root of the connection between the circulation pipe 2 and the fuel filler pipe 1. The lower side of the raised ring is welded and fixed to the flared section sidewall of the main filling pipe, ensuring the sealing and strength of the connection.

[0026] To optimize pipeline layout and fixation, three spaced first supports 5 are installed on the outside of the bends of the main filling pipe and the circulation pipe 2; at the same time, a second support 6 is installed on the outside of the flared section of the main filling pipe; the desorption pipe 3 and the vent pipe 4 are fixed together by three independent fixing clamps 8. These fixing clamps 8 correspond one-to-one with the three first supports 5 and form a quick-locking structure, realizing the modular integration and efficient assembly of the pipeline.

[0027] To address the technical problem that the refueling pipe 1, which is fixed with a rubber sleeve but lacks a lower flange, is prone to circumferential rotation during assembly, leading to misalignment of the refueling port assembly, this invention specifically incorporates a limiting structure on the second bracket 6. This limiting structure can cooperate with the body sheet metal 7 to effectively restrict the circumferential rotation of the refueling pipe 1 assembly, thereby ensuring precise alignment of the refueling port and the refueling cap and eliminating the potential for misalignment during assembly.

[0028] like Figure 2As shown, the first support 5 includes a small arc-shaped part 501, a large arc-shaped part 502, and a straight plate part 503 integrally connected. The inner wall of the small arc-shaped part 501 is welded and fixed to the outer periphery of the circulation pipe 2, and the large arc-shaped part 502 is welded and fixed to the outer periphery of the refueling pipe 1, forming a "dual-pipe shared support" structure, which can effectively cancel the vibration transmission between them, thereby protecting the internal structure of the pipeline and the connection. In addition, a fixing hole is provided on the straight plate part 503. This hole is specifically used for engaging with the fixing pipe clamp 8, realizing quick and reliable assembly between the support and the integrated pipe bundle.

[0029] like Figure 3 As shown, the limiting structure is a protrusion 601 that mates with the mounting holes on the body sheet metal 7. This protrusion 601 directly engages with pre-drilled round / diamond holes on the body bracket, thus achieving a rigid restriction on the circumferential rotation of the fuel filler pipe 1 assembly. This completely solves the assembly misalignment problem caused by the lack of a lower flange when using rubber sleeves for fixing. In addition, the protrusion 601 itself constitutes a precise assembly guide feature, ensuring that the fuel filler pipe 1 assembly can only be installed at the single correct angle, achieving a mistake-proof design. This protrusion 601 can usually be integrally stamped with the second bracket 6 without adding extra parts, resulting in a robust structure and low cost.

[0030] Both the desorption tube 3 and the vent tube 4 are nylon tubes. Because the tube surfaces are smooth and their positions are difficult to fix, a plastic fixing clamp 8 is used to achieve anti-channeling and limiting function by interfering with the nylon tube. Figure 4 As shown, the fixing pipe clamp is a one-piece injection molded plastic part with good toughness and strength, including a first pipe clamp part 801, a second pipe clamp part 802, a connecting bridge part 803 and a locking part 804.

[0031] The first clamp part 801 is an open ring that fits the outer diameter of the desorption tube 3 and is used to clamp the desorption tube 3. The second clamp part 802 is an open C-shaped structure used to clamp the desorption vent tube 4. One side of the second clamp part 802 is provided with an L-shaped elastic latch 802a for elastically clamping the pipeline, and the other side is provided with a T-shaped groove 802b for engaging and connecting with the elastic latch 802a. The C-shaped opening allows the desorption tube 3 and the vent tube 4 to be directly inserted into the corresponding clamp part from the opening, without having to completely remove the bolts as with a closed clamp. Alternatively, a snap-fit ​​mechanism can be used; the L-shaped elastic latch 802a and the T-shaped groove 802b work together to achieve "one-click locking": During assembly, the desorption pipe 3 and the vent pipe 4 are pressed in from the opening, and the first clamp part 801 and the second clamp part 802 deform and then reset, thereby clamping the pipes in the corresponding clamps to prevent axial movement. Finally, the latch 802a is pushed to make it elastically deform and embed into the T-shaped groove 802b. The L-shaped fold of the latch 802a and the T-shaped protrusion of the groove 802b form a mechanical interlock, completing the clamping and improving assembly efficiency.

[0032] The connecting bridge section 803 adopts a stiffening plate structure to connect the first pipe clamp section 801 and the second pipe clamp section 802 into a whole, so that the two maintain a predetermined relative position and form a compact gourd-shaped layout, which optimizes the use of space.

[0033] The engaging part 804 is integrally connected to the first pipe clamp part 801, and is used to form a detachable engaging connection with the corresponding first bracket 5. Specifically, the engaging part 804 includes a triangular elastic hook 804a and an arc-shaped limiting plate 804b; the end of the elastic hook 804a is open and provided with a stepped barb 804c; the first bracket 5 is provided with a rectangular locking hole 503a that mates with the elastic hook 804a; during assembly, the hook 804a on the fixed pipe clamp is aligned with the rectangular locking hole 503a, and a certain pushing force is applied to engage the hook. The two beveled sides of 804a form multi-point sliding contact with the right-angled side of the locking hole 503a, resulting in more even force distribution. At the same time, the elastic deformation capability of the hook 804a allows it to be slightly compressed during insertion and reset after passing through the locking hole 503a. The barb 804c at the end of the hook 804a forms a one-way mechanical lock with the edge of the locking hole 503a to prevent accidental dislodgement. The arc-shaped limiting plate 804b provides lateral auxiliary positioning and support, thereby completing the rapid and secure positioning of the entire component and ensuring the uniqueness and accuracy of the assembly.

[0034] The circulation pipe 2 is equipped with an integrally formed throttling structure 201. This structure is not an independent additional part, but is formed in one step by radially clamping and extruding the side wall of the circulation pipe 2 using special tooling. This causes local inward plastic deformation of the pipe wall, forming a throttling orifice with a concave lens-shaped cross-section. Compared with traditional machining necking, this process is greatly simplified and has higher dimensional consistency. Downstream of this throttling orifice is an arc-shaped buffer section 202, the length of which is 8 to 10 times the inner diameter of the circulation pipe 2 (56 mm in this embodiment). Figure 5 and 6 As shown. The arc length of this section allows the high-speed turbulence generated after the fuel flows through the throttle orifice to be adequately buffered, attenuated, and reorganized before flowing out of the circulation pipe 2.

[0035] The width H of the throttling orifice at its narrowest point ranges from 2.6 mm to 2.9 mm. This is an optimization result based on system fluid dynamics analysis and experimental verification, as shown in Table 1. This table compares the flow cross-sectional area (S) of a traditional circular throttling orifice and the clamp-shaped throttling orifice of this invention at different dimensions. The data in the table clearly reveal the significant differences in key structural dimensions between the two different structures when achieving similar flow capacity (i.e., cross-sectional area).

[0036]

[0037] As can be seen from the table above, to achieve a specific target fuel vapor flow rate (typically corresponding to a certain required throttling cross-sectional area), the width H required by the clamp-shaped throttling orifice of the present invention is smaller than the diameter required by the conventional circular throttling orifice. For example, to obtain a throttling cross-sectional area of ​​approximately 6.15-6.18 mm², the conventional solution requires a circular throttling orifice with a diameter of 2.8 mm, while the present invention only requires a clamp-shaped throttling orifice with a width H of 2.6 mm.

[0038] Within the H value range of 2.6mm to 2.9mm, the cross-sectional area variation curve (SH relationship) of the clamp-shaped throttling orifice exhibits good linearity and sensitivity. This range represents the "optimal working interval" where the throttling effect is significant and easily controlled precisely by tooling. If H < 2.6mm, it can easily lead to a surge in processing difficulty and a risk of clogging; if H > 2.9mm, the throttling effect weakens and cannot meet the flow requirements of the ORVR system.

[0039] The advantages of this invention are as follows: the one-time extrusion molding of the sidewall avoids the multiple processing steps of traditional end throttling, solves the problems of complex processing, difficult size control and easy blockage of end throttling orifice, and improves product reliability and consistency; the "concave lens-shaped" throttling orifice combined with the arc-shaped buffer section downstream of it, which is 8-10 times the pipe diameter, can effectively smooth the flow velocity, suppress the generation of eddies, and minimize the flow disturbance and pressure pulse of fuel vapor, thereby significantly reducing the airflow noise generated during refueling and fundamentally improving the stability of the fluid from the perspective of flow channel morphology.

[0040] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A refueling pipe assembly with a restriction structure, comprising a refueling pipe and a circulation pipe, the circulation pipe being provided with a restriction structure, characterized in that, The throttling structure is a locally extruded deformation part formed on the side wall of the circulation pipe. The deformation part protrudes into the pipe and forms a throttling orifice with a concave lens-shaped cross-section on the inner side of the pipe wall. An arc-shaped buffer section is provided between the throttling orifice and the end of the air outlet of the circulation pipe.

2. The refueling pipe assembly with a throttling structure according to claim 1, characterized in that, The width H of the throttling orifice at its narrowest point is 2.6 mm to 2.9 mm.

3. The refueling pipe assembly with a throttling structure according to claim 1, characterized in that, The throttling orifice is formed in one step by radially clamping and extruding the wall of the circulation pipe.

4. The refueling pipe assembly with a throttling structure according to claim 1, characterized in that, The length of the arc-shaped buffer section is 8 to 10 times the inner diameter of the circulation pipe.

5. The refueling pipe assembly with a throttling structure according to claim 1, characterized in that, The refueling pipe includes a refueling cup, a refueling main pipe, and a refueling hose arranged in sequence; the outlet end of the circulation pipe is a straight pipe with a flat opening, and it penetrates the flared section sidewall of the refueling main pipe, so that the circulation pipe is connected to the refueling pipe; a raised ring is provided at the root of the connection between the circulation pipe and the refueling pipe, and the lower side of the raised ring is welded and fixed to the flared section sidewall of the refueling main pipe.

6. The refueling pipe assembly with a throttling structure according to claim 1, characterized in that, It also includes a desorption pipe and a vent pipe; several first supports are arranged at intervals on the outside of the bent section of the main filling pipe and the circulation pipe; a second support is arranged on the outside of the flared section of the main filling pipe; several fixed pipe clamps are provided on the outer sleeve of the desorption pipe and the vent pipe, and the fixed pipe clamps are arranged one-to-one with the first supports and form a locking structure with the corresponding first supports; a limiting structure is provided on the second support to restrict the circumferential rotation of the refueling pipe.

7. A refueling pipe assembly with a throttling structure according to claim 6, characterized in that, The first bracket includes a small arc-shaped part, a large arc-shaped part, and a straight plate part that are integrally connected. The inner wall of the small arc-shaped part is fixedly connected to the outer periphery of the circulation pipe, the large arc-shaped part is fixedly connected to the outer periphery of the refueling pipe, and the straight plate part has a fixing hole for engaging with a fixing pipe clamp.

8. A refueling pipe assembly with a throttling structure according to claim 6, characterized in that, The fixing clamp is an integrally formed structural component, including a first clamp part, a second clamp part, a connecting bridge part, and a locking part; the first clamp part is used to clamp the desorption pipe; the second clamp part is used to clamp the desorption vent pipe; the connecting bridge part is integrally connected to the first clamp part and the second clamp part, so that the two maintain a predetermined relative position; the locking part is integrally connected to the first clamp part, and is used to form a detachable locking connection with the corresponding first bracket.

9. A refueling pipe assembly with a throttling structure according to claim 8, characterized in that, The second pipe clamp is an open C-shaped structure, with an L-shaped elastic latch on one side for elastically clamping the pipe, and a T-shaped groove on the other side for engaging and connecting with the elastic latch; the engaging part includes a triangular elastic hook and an arc-shaped limiting plate; the end of the elastic hook is open and has a stepped barb; the first bracket has a rectangular locking hole that engages with the elastic hook.

10. A refueling pipe assembly with a throttling structure according to claim 6, characterized in that, The limiting structure is a protrusion or buckle that mates with mounting holes on the vehicle body sheet metal.

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