Top-mounted tank isolation valve

Abstract

The invention discloses a top-to-top fuel tank isolation valve in the technical field of automobile isolation valves, comprising: a valve housing, a tube cavity for air circulation is provided inside, the tube cavity is divided into an upper tube cavity and a lower tube cavity by an inner ring platform, the upper tube cavity and the lower tube cavity are connected through an air vent in the middle of the inner ring platform, and a fuel tank pipeline joint connected to the upper tube cavity is provided on the valve housing; an electromagnetic coil assembly is provided at the upper end of the valve housing, a bottom cover is provided at the bottom of the valve housing, and an upper valve head assembly is provided to block or open the air vent; a lower valve head assembly is provided to block or open the air vent, and a pressure relief air path is provided in the upper valve head assembly; the electromagnetic coil assembly is installed on the top of the valve housing to control the upper valve head assembly to approach or move away from the inner ring platform. The invention solves the problem that the valve in the fuel tank is closed due to excessive flow in the initial pressure relief process of the existing fuel tank isolation valve, and can be used in fuel vehicles.

Description

Technical Field

[0001] The invention relates to the technical field of automobile isolation valves, and in particular to an oil tank isolation valve. Background Art

[0002] With the vigorous development of the modern automobile industry, the control of automobile exhaust emissions, fuel evaporation and leakage pollution and other issues has become one of the key contents in the automobile research and development process. Based on the requirements of the published "GB18352.6-2016 Light Vehicle Pollutant Emission Limits and Measurement Methods (China Phase VI)", the amount of automobiles allowed to evaporate into the atmosphere needs to be more strictly controlled. In the automobile fuel evaporation control system (EVAP), the oil and gas from the fuel tank are temporarily stored in the carbon canister connected to it, and finally enter the engine for combustion through desorption.

[0003] The fuel tank isolation valve (FTIV valve) is controlled by a special module in the engine control system. The system will open or close the FTIV valve according to different needs. Normally, the FTIV valve is normally closed, which isolates the high-pressure fuel tank to form an independent and closed space to ensure that the evaporated fuel gas will not overflow. However, in some working conditions, the FTIV valve must be opened to ensure the normal operation of other vehicle functions.

[0004] For example, the pressure relief request in the fuel tank during refueling: Since the FTIV valve is closed for a long time, the pressure in the fuel tank is relatively high. Therefore, when the vehicle needs to be refueled, in order to prevent the fuel from back-spraying, the FTIV valve needs to be opened before opening the fuel tank cap. After the fuel tank pressure is released to an acceptable range, the fuel tank cap can be opened by the driver. Through such an effective protection mechanism, it is possible to avoid fuel splashing and causing harm to personnel, while also ensuring that the fuel tank can be filled normally. Specific operation and control process: The driver triggers the refueling button and sends a refueling request to the ECU. The ECU sends a control signal based on the fuel tank pressure to control the FTIV valve to open. After the fuel tank pressure drops to a certain value, the fuel tank cap is released and can be opened.

[0005] Generally, the time interval from refueling request to opening the fuel tank cap is quite short, the shortest is only about 1.5 seconds. Even if the pressure of the fuel tank reaches 20 to 35 kPa, by opening the FTIV valve, the pressure of the fuel tank will be reduced to about 3 kPa within 10 seconds, which will not delay the driver too much time. At the same time, there will be special instructions for this situation in the vehicle manual.

[0006] A fuel tank isolation valve control system is disclosed in the prior art, with a publication date of 2022.01.11 and a publication number of CN113915031A. The disadvantage is that during actual use, when the pressure difference between the inside and outside of the fuel tank is too large, a large instantaneous flow will be generated when the FTIV valve is opened, which will cause the valve in the fuel tank to close, making it impossible to vent the fuel tank and thus refuel. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a top-to-top oil tank isolation valve to solve the problem that the existing oil tank isolation valve is closed due to excessive flow during the initial pressure relief process.

[0008] The object of the present invention is achieved in this way: a top-to-top oil tank isolation valve, comprising:

[0009] The valve housing has a tube cavity for air circulation inside, the tube cavity is divided into an upper tube cavity and a lower tube cavity by the inner ring platform, the upper tube cavity and the lower tube cavity are connected through the vent hole in the middle of the inner ring platform, and the valve housing is provided with an oil tank pipeline joint connected to the upper tube cavity;

[0010] The upper valve head assembly is movably arranged in the upper tube cavity, and is close to or away from the inner ring platform to block or open the vent hole. When blocking, the upper valve head assembly and the inner ring platform form a first sealing surface;

[0011] The lower valve head assembly is movably arranged in the lower tube cavity, and is close to or away from the upper valve head assembly to block or open the vent hole. When blocking, a second sealing surface is formed between the upper valve head assembly and the lower valve head assembly. The upper valve head assembly is provided with a pressure relief air path connecting the upper tube cavity and the lower tube cavity when the second sealing surface is opened;

[0012] The electromagnetic coil assembly is installed on the top of the valve housing to control the upper valve head assembly to move closer to or away from the inner ring platform;

[0013] A bottom cover is installed at the bottom of the valve housing, and a carbon canister pipe joint connected to the lower pipe cavity is provided on the bottom cover;

[0014] The flow limiting structure includes a ventilation groove opened on the inner wall of the lower tube cavity, and a boss matched with the ventilation groove is processed on the inner wall of the bottom cover. The gap between the ventilation groove and the lower valve head assembly is larger than the gap between the boss and the lower valve head assembly. A flow limiting air path is formed between the lower valve head assembly and the ventilation groove and the boss.

[0015] The present invention solves the problem of blockage of the FLVV valve in the fuel tank due to large flow by setting a flow limiting structure in the lower tube cavity of the FTIV valve. The working principle is as follows:

[0016] By designing the vent groove and the boss, and the gap between the lower valve head assembly and the vent groove is larger than the gap between the boss and the lower valve head assembly, when exhausting, the flow is calculated according to the smaller air path (the gap between the boss and the lower valve head assembly). When the pressure in the oil tank is reduced, the lower valve head gradually rises under the action of the lower spring, so that the side of the lower valve head is separated from the air path restriction of the boss, completing the conversion to the vent groove air path, and starting to exhaust at a large flow rate. Because the pressure in the oil tank has been reduced at this time, it will no longer cause the FLVV valve in the oil tank to be blocked.

[0017] In order to facilitate the carbon canister to replenish air into the fuel tank, the upper valve head assembly includes an upper valve head connected to the electromagnetic coil assembly, and an upper spring is also provided between the upper valve head and the electromagnetic coil assembly. The upper spring provides thrust to push the upper valve head close to the inner ring platform, and the pressure relief air path is opened in the upper valve head.

[0018] In order to facilitate the pressure relief from the fuel tank into the carbon canister, the lower valve head assembly includes a lower valve head supported on the bottom cover by a lower spring. The lower spring provides thrust to push the lower valve head close to the upper valve head. The top of the lower valve head is provided with an outer ring platform for contacting with the upper valve head to form a second sealing surface.

[0019] In order to solve the stability problem of the upper valve head assembly and the lower valve head assembly during movement, the top of the outer ring platform extends upward to form a guide column, and a guide channel cooperating with the guide column is provided in the upper valve head, and the guide column is inserted into the guide channel.

[0020] In order to facilitate the assembly of the upper valve head assembly and enhance the sealing performance, the upper valve head includes a sealing gasket connected to the bottom of the movable frame, and the bottom of the sealing gasket is provided with an outer ring protrusion for forming a first sealing surface and an inner ring protrusion for forming a second sealing surface.

[0021] In order to facilitate the assembly of the upper valve head assembly, a connecting portion is provided on the top of the movable frame, and a connecting hole is opened on the connecting portion. The electromagnetic coil assembly includes a moving iron core movably arranged inside the electromagnetic coil, a T-shaped head is provided at the bottom of the moving iron core, and a notch for inserting the T-shaped head is processed on the side of the connecting portion.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention ensures the reliability of the FLVV valve in the fuel tank during operation through the flow limiting structure, greatly improving the safety and reliability of the entire fuel tank system. The flow limiting structure can be realized by only partially improving the original structure, without adding independent parts, thus reducing the cost.

[0024] 2. During the design, a sealing gasket is used to cooperate with the inner ring platform and the lower valve head to form two independent sealing surfaces, which simplifies the structure, reduces the design difficulty, reduces the production cost, optimizes the gas path, and makes the pressure relief and gas replenishment smoother.

[0025] 3. The guide structure (guide channel, guide column) between the upper valve head and the lower valve head provides the possibility for the top-to-top structure (simplified structure), making the upper valve head and the lower valve head more stable and reliable when working. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the external structure of the present invention.

[0028] Figure 2 It is a schematic diagram of the internal structure of the present invention.

[0029] Figure 3 It is a schematic diagram of the current limiting structure in the present invention.

[0030] Figure 4 It is a partial cross-sectional view of the upper valve head assembly and the lower valve head assembly in the present invention.

[0031] Figure 5 It is a schematic diagram of the connection between the present invention and the fuel tank and carbon canister.

[0032] Figure 6 This is a gas flow diagram of the working state of the present invention.

[0033] Figure 7 This is a two-way gas flow diagram of the present invention in working state.

[0034] Figure 8 This is a three-way gas flow diagram of the present invention in working state.

[0035] Fig. 9 This is a schematic diagram of the gas flow direction at the flow limiting structure during operation of the present invention.

[0036] Among them, 1 valve housing, 1a upper tube cavity, 1b lower tube cavity, 1c inner ring platform, 1d vent hole, 1e fuel tank pipeline joint, 2 electromagnetic coil assembly, 2a electromagnetic coil, 2b moving iron core, 3 bottom cover, 3a carbon canister pipeline joint, 4 upper valve head assembly, 4a movable frame, 4b sealing gasket, 4c outer ring protrusion, 4d inner ring protrusion, 4e upper spring, 4f guide channel, 5 lower valve head assembly, 5a lower valve head, 5b lower spring, 5c outer ring platform, 5d guide column, 6 flow limiting structure, 6a vent groove, 6b boss. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] like Figure 1-4 A top-to-top tank isolation valve is shown, comprising:

[0039] The valve housing 1 adopts a tubular structure. The lumen in the valve housing 1 is divided into an upper lumen 1a and a lower lumen 1b through an inner ring platform 1c. The upper lumen 1a and the lower lumen 1b can be connected through a vent hole 1d in the middle of the inner ring platform 1c. A fuel tank pipeline connector 1e connected to the upper lumen 1a is processed on the outer wall of the valve housing 1 and is completed together through the injection molding process. The fuel tank pipeline connector 1e is connected to the automobile fuel tank;

[0040] The electromagnetic coil assembly 2 is installed on the top of the valve housing 1, closing the valve housing 1 from the top, and includes a moving iron core 2b movably arranged inside the electromagnetic coil 2a, and a T-shaped head is provided at the bottom of the moving iron core 2b;

[0041] The bottom cover 3 is installed at the bottom of the valve housing 1 to close the valve housing 1 from the bottom. The bottom center of the bottom cover 3 is provided with a carbon canister pipeline joint 3a connected to the lower tube cavity 1b;

[0042] The upper valve head assembly 4 includes an upper valve head connected to the lower end of the moving iron core 2b, an upper spring 4e is further provided between the upper valve head and the electromagnetic coil 2a, one end of the upper spring 4e abuts against the bottom of the electromagnetic coil 2a, and the other end abuts against the top of the upper valve head, the upper valve head includes a sealing gasket 4b connected to the bottom of the movable frame 4a, the bottom of the sealing gasket 4b is provided with an outer ring protrusion 4c for forming a first sealing surface and an inner ring protrusion 4d for forming a second sealing surface, an L-shaped connecting part is provided at the top center of the movable frame 4a, a connecting hole is provided on the connecting part, a notch for inserting a T-shaped head is processed on the side of the connecting part, the T-shaped head of the moving iron core 2b is inserted and movably connected with the connecting part, and a pressure relief air path (i.e., a guide channel 4f) is further provided at the center of the movable frame 4a;

[0043] The lower valve head assembly 5 comprises a lower valve head 5a supported on the bottom cover 3 via a lower spring 5b, one end of the lower spring 5b abuts against the bottom cover 3, and the other end abuts against the bottom of the lower valve head 5a, an outer ring platform 5c is provided at the top center of the lower valve head 5a, and a guide column 5d is formed by extending upward from the top center of the outer ring platform 5c, and a guide channel 4f matching with the guide column 5d is provided in the upper valve head, and the guide column 5d is inserted into the guide channel 4f;

[0044] The flow limiting structure 6 includes a ventilation groove 6a provided on the inner wall of the lower tube cavity, and a boss 6b matching the ventilation groove 6a is processed on the inner wall of the bottom cover 3. The gap between the ventilation groove 6a and the lower valve head assembly 5 is larger than the gap between the boss 6b and the lower valve head assembly 5, and a flow limiting air path is formed between the lower valve head assembly 5 and the ventilation groove 6a and the boss 6b.

[0045] like Figure 5 As shown, it is a schematic diagram of the connection between the present invention and the fuel tank and the carbon canister. The working principle of the present invention includes the following three working states:

[0046] like Figure 6 The working state shown is one, refueling and exhausting:

[0047] During the refueling process, the pressure in the fuel tank is too high, and it is necessary to exhaust gas from the fuel tank to the carbon canister. At this time, the electromagnetic coil assembly 2 is controlled to work, driving the moving iron core 2b to move upward, and the moving iron core 2b drives the upper valve head assembly 4 to rise, so that the outer ring protrusion 4c is separated from the inner ring platform 1c, opening the first sealing surface, and the fuel tank exhausts gas into the carbon canister;

[0048] During the refueling process, the pressure in the fuel tank is too low and it is necessary to add air from the carbon canister into the fuel tank. At this time, the electromagnetic coil assembly 2 is controlled to work, driving the moving iron core 2b to move upward, and the moving iron core 2b drives the upper valve head assembly 4 to rise, so that the outer ring protrusion 4c is separated from the inner ring platform 1c, opening the first sealing surface, and adding air from the carbon canister into the fuel tank.

[0049] like Figure 7 Working state 2 shown, normal exhaust:

[0050] After refueling is completed, the electromagnetic coil assembly 2 drives the moving iron core 2b to move downward, so that the outer ring protrusion 4c contacts the inner ring platform 1c, and the first sealing surface is closed. At the same time, the lower valve head 5a contacts the inner ring protrusion 4d under the action of the lower spring 5b, and the second sealing surface is closed; when the pressure in the oil tank increases and the pressure plus the weight of the lower valve head 5a exceeds the elastic force of the lower spring 5b, the air pressure pushes the lower valve head 5a downward from the pressure relief gas path, opens the second sealing surface, and the oil tank exhausts air into the carbon canister. After the pressure inside and outside the oil tank is balanced, the second sealing surface is re-closed under the action of the lower spring 5b;

[0051] like Figure 8 Working state three shown, normal air replenishment:

[0052] When the pressure in the fuel tank decreases and the air pressure in the carbon canister exceeds the elastic force of the upper valve head and the upper spring 4e, the upper valve head is lifted up to open the first sealing surface, and the carbon canister replenishes air into the fuel tank. After the pressure inside and outside the fuel tank is balanced, the first sealing surface is re-closed under the action of the upper spring 4e.

[0053] The present invention forms two independent sealing surfaces through a sealing gasket 4b, an inner ring platform 1c and a lower valve head 5a, which simplifies the structure compared with the traditional method, eliminates the need to design a ventilation pipe in the middle of the valve housing 1, reduces the design difficulty, reduces the production cost, optimizes the gas path, and makes the pressure relief and air replenishment smoother; the guide structure (guide channel 4f, guide column 5d) between the upper valve head and the lower valve head 5a provides the possibility of a top-to-top structure (simplified structure), so that the upper valve head and the lower valve head 5a are more stable and reliable when working.

[0054] like Fig. 9 The figure shows a schematic diagram of flow limiting of the present invention, the thick arrow at the vent groove 6a indicates a large flow, and the thin arrow at the boss 6b indicates a small flow; when exhausting, the lower end face of the lower valve head 5a is located in the bottom cover 3 area, and the flow is calculated according to the smaller air path (the gap between the boss 6b and the lower valve head 5a). When the pressure in the oil tank is increased, the lower valve head 5a gradually rises under the action of the lower spring 5b, so that the lower end face of the lower valve head 5a exceeds the bottom cover 3 and is separated from the air path restriction of the boss 6b. The lower end face is located in the lower tube cavity 1b, completing the conversion to the air path of the vent groove 6a, and starting to exhaust at a large flow rate. Because the pressure in the oil tank has been reduced at this time, it will no longer cause the FLVV valve in the oil tank to be blocked. The structure designed in this way only achieves flow limiting through structural improvement, and no independent structure is required, thereby reducing costs.

[0055] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A top-mounted oil tank isolation valve, characterized in that: include: A valve housing (1) is provided with a tube cavity for air circulation inside, the tube cavity is divided into an upper tube cavity (1a) and a lower tube cavity (1b) by an inner ring platform (1c), the upper tube cavity (1a) and the lower tube cavity (1b) are connected via a vent hole (1d) in the middle of the inner ring platform (1c), and an oil tank pipeline joint (1e) connected to the upper tube cavity (1a) is provided on the valve housing (1); The upper valve head assembly (4) is movably arranged in the upper tube cavity (1a) and moves close to or away from the inner ring platform (1c) to block or open the vent hole (1d). When blocking, the upper valve head assembly (4) and the inner ring platform (1c) form a first sealing surface. A lower valve head assembly (5) is movably arranged in the lower tube cavity (1b) and moves closer to or farther from the upper valve head assembly (4) to block or open the vent hole (1d); when blocking, a second sealing surface is formed between the upper valve head assembly (4) and the lower valve head assembly (5); and a pressure relief air path is provided in the upper valve head assembly (4) to connect the upper tube cavity (1a) and the lower tube cavity when the second sealing surface is opened; An electromagnetic coil assembly (2) is mounted on the top of the valve housing (1) to control the upper valve head assembly (4) to move closer to or farther from the inner ring platform (1c); A bottom cover (3) is mounted on the bottom of the valve housing (1), and a carbon canister pipe joint (3a) connected to the lower pipe cavity (1b) is provided on the bottom cover (3); The flow-limiting structure (6) comprises a venting groove (6a) formed on the inner wall of the lower tube cavity, a boss (6b) matched with the venting groove (6a) is processed on the inner wall of the bottom cover (3), the gap between the venting groove (6a) and the lower valve head assembly (5) is larger than the gap between the boss (6b) and the lower valve head assembly (5), and a flow-limiting gas path is formed between the lower valve head assembly (5) and the venting groove (6a) and the boss (6b); The upper valve head assembly (4) comprises an upper valve head connected to the electromagnetic coil assembly (2), an upper spring (4e) is provided between the upper valve head and the electromagnetic coil assembly (2), the upper spring (4e) provides a thrust to push the upper valve head close to the inner ring platform (1c), and the pressure relief gas path is provided in the upper valve head; The lower valve head assembly (5) comprises a lower valve head (5a) supported on the bottom cover (3) via a lower spring (5b), the lower spring (5b) providing a thrust to push the lower valve head (5a) close to the upper valve head, and an outer ring platform (5c) is provided on the top of the lower valve head (5a) for contacting with the upper valve head to form a second sealing surface; The upper valve head comprises a sealing gasket (4b) connected to the bottom of the movable frame (4a), and the bottom of the sealing gasket (4b) is provided with an outer ring protrusion (4c) for forming a first sealing surface and an inner ring protrusion (4d) for forming a second sealing surface.

2. The top-to-top tank isolation valve according to claim 1, characterized in that: The top of the outer ring platform (5c) extends upward to form a guide column (5d), and a guide channel (4f) cooperating with the guide column (5d) is provided in the upper valve head, and the guide column (5d) is inserted into the guide channel (4f).

3. The top-to-top tank isolation valve according to claim 1, characterized in that: A connecting portion is provided on the top of the movable frame (4a), and a connecting hole is provided on the connecting portion. The electromagnetic coil assembly (2) comprises a moving iron core (2b) movably arranged inside the electromagnetic coil (2a), a T-shaped head is provided at the bottom of the moving iron core (2b), and a notch is processed on the side of the connecting portion for inserting the T-shaped head.

Images