Oil tank isolating valve

Abstract

The utility model provides an oil tank isolating valve which comprises a valve body, a positive pressure valve unit, a negative pressure valve unit and an electromagnetic valve unit. The valve body comprises a left cavity and a right cavity, a partition plate is arranged in the valve body to divide the left cavity into a first cavity and a second cavity and divide the right cavity into a third cavity and a fourth cavity, and a first air hole and a second air hole are formed in the partition plate; the positive pressure valve unit comprises a positive pressure valve seat, a positive pressure spring and a sealing gasket, and the positive pressure valve seat is located in the third cavity; the two ends of the positive pressure spring abut against the bottom of the third cavity and the positive pressure valve seat correspondingly. The sealing gasket is hermetically attached to the partition plate; the negative pressure valve unit is used for being hermetically attached to the partition plate; and the electromagnetic valve unit is connected with the negative pressure valve unit. The negative pressure valve unit does not move downwards along with the positive pressure valve seat, the acting force of the negative pressure valve unit does not need to be overcome, the smaller the elastic force needed by the positive pressure spring is, the smaller the size specification is, and the cost can be reduced; and the negative pressure valve unit and the positive pressure valve unit are not coaxial and do not need to be aligned, so that the assembly difficulty is lower.

Description

Technical Field

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

[0002] In a gasoline vapor emission system, gasoline vapor generated in the fuel tank is discharged through an exhaust valve into the carbon canister, where it is effectively adsorbed by the activated carbon inside. After the engine is started, fresh air is drawn into the carbon canister, and the fuel vapor adsorbed by the activated carbon in the canister is re-introduced into the engine for combustion, improving fuel efficiency. However, plug-in hybrid vehicles sometimes operate in electric drive mode for extended periods. In this mode, the carbon canister lacks a desorption function, which can easily lead to saturation of the canister's adsorption capacity. Fuel vapor is then directly released into the atmosphere, causing environmental pollution and fuel waste. Furthermore, when the vehicle is in electric drive mode for extended periods, fuel vaporization and accumulation can lead to excessive pressure in the fuel tank, potentially damaging it. In these cases, the valve requires an automatic pressure relief function. Alternatively, if the fuel in the tank is used rapidly, the internal pressure may be too low, causing damage due to compression from external atmospheric pressure. In these cases, the valve requires an automatic pressure boost function.

[0003] In the prior art, the negative pressure valve moves with the positive pressure valve. When the positive pressure valve moves, the positive pressure spring needs to overcome the force of the negative pressure valve. Therefore, the greater the elastic force required by the positive pressure spring, the larger the size of the positive pressure spring and the higher the cost. Utility Model Content

[0004] In view of this, the present invention proposes a fuel tank isolation valve to solve the technical problem proposed in the above background technology that the negative pressure valve moves together with the positive pressure valve. When the positive pressure valve moves, the positive pressure spring needs to overcome the force of the negative pressure valve. Therefore, the greater the elastic force required by the positive pressure spring, the larger the size of the positive pressure spring and the higher the cost.

[0005] The technical solution of the present utility model is achieved as follows:

[0006] The utility model provides a fuel tank isolation valve, comprising a valve body, a positive pressure valve unit, a negative pressure valve unit and a solenoid valve unit, wherein:

[0007] The valve body includes a left cavity and a right cavity arranged in parallel on the left and right sides. A partition is provided in the valve body to separate the left cavity into a first cavity and a second cavity distributed in a lower-upper direction, and to separate the right cavity into a third cavity and a fourth cavity distributed in a lower-upper direction. The third cavity is connected to the first cavity, and the fourth cavity is connected to the second cavity. The partition is provided with a first air hole connecting the first cavity and the second cavity, and a second air hole connecting the third cavity and the fourth cavity. The third cavity is connected to a first channel for connecting to a carbon canister, and the second cavity is connected to a second channel for connecting to a fuel tank.

[0008] The positive pressure valve unit includes a positive pressure valve seat, a positive pressure spring, and a sealing gasket. The positive pressure valve seat is located in the third cavity. Two ends of the positive pressure spring abut against the bottom of the third cavity and the positive pressure valve seat, respectively. The lower surface of the sealing gasket is connected to the surface of the positive pressure valve seat away from the bottom of the first cavity. The upper surface of the sealing gasket is used to seal with the partition to close the second air hole.

[0009] The negative pressure valve unit is located in the second cavity and is used to seal with the partition to close the first air hole;

[0010] The solenoid valve unit is installed at one end of the second cavity away from the partition and is connected to the negative pressure valve unit;

[0011] The medium enters the second cavity from the second channel, then enters the third cavity from the second air hole through the fourth cavity, and is discharged to the carbon canister through the first channel; or the medium enters the third cavity from the first channel, then enters the second cavity from the first air hole through the first cavity, and is replenished to the fuel tank through the first channel.

[0012] On the basis of the above technical solution, preferably, an annular lip located outside the second air hole is provided on the edge of one side of the sealing gasket away from the positive pressure valve seat, and the annular lip is used for sealingly fitting with the partition.

[0013] On the basis of the above technical solution, preferably, the partition is provided with an abutment ring protruding toward the second cavity at the edge of the first air hole, and the abutment ring is used for sealingly fitting with the negative pressure valve unit.

[0014] Based on the above technical solution, preferably, a first guide plate is provided at the bottom of the third cavity, and a second guide plate is provided at the bottom of the positive pressure valve seat, the inner diameter of the second guide plate is smaller than the inner diameter of the first guide plate, and the positive pressure spring is located between the second guide plate and the first guide plate.

[0015] Based on the above technical solution, preferably, a plurality of raising plates are provided at the bottom of the third cavity, and the plurality of raising plates are connected to the inner wall of the first guide plate, and the positive pressure spring abuts between one end of the raising plate away from the bottom of the third cavity and the positive pressure valve seat.

[0016] On the basis of the above technical solution, preferably, the negative pressure valve unit includes a negative pressure valve seat and a negative pressure spring, the negative pressure valve seat is connected to the solenoid valve unit, one end of the negative pressure spring abuts against the solenoid valve unit, and the other end of the negative pressure spring abuts against the negative pressure valve seat, which is used to make the negative pressure valve seat abut against the partition, and the negative pressure valve seat closes the first air hole.

[0017] On the basis of the above technical solution, preferably, the solenoid valve unit includes a valve housing, a coil and a push rod; the valve housing is connected to the second cavity, and a sliding hole is provided inside the valve housing; the coil is provided at the top of the valve housing for magnetically attracting the push rod after power is turned on; the push rod is made of magnetic material, the push rod is slidably installed in the sliding hole, and is connected to the negative pressure valve seat.

[0018] On the basis of the above technical solution, preferably, the solenoid valve unit also includes a positioning plate located in the valve housing and a connecting seat located in the second cavity, and the connecting seat includes a baffle and a guide cylinder; the push rod abuts against the end of the baffle away from the guide cylinder, and the baffle can abut against the positioning plate; the guide cylinder is connected to the end of the baffle away from the coil, and the negative pressure spring is sleeved on the push rod and located in the guide cylinder.

[0019] On the basis of the above technical solution, preferably, the negative pressure valve seat includes an abutment seat and a sleeve tube, the abutment seat is used to abut against the partition; the sleeve tube is arranged at the top of the abutment seat, and a connecting cavity is provided inside the sleeve tube, and a mounting hole is provided on the top surface of the sleeve tube, and the diameter of the mounting hole is smaller than the diameter of the inner wall of the connecting cavity, and an axis groove section is provided at the end of the push rod away from the coil, the axis groove section is provided in the mounting hole, and the end of the push rod is located in the connecting cavity.

[0020] Based on the above technical solution, preferably, a plurality of first ribs are arranged along the circumferential direction of the inner wall of the second cavity, and the first ribs extend from the inner wall of the second cavity along the diameter direction of the second cavity, and the end of the first rib away from the inner wall of the second cavity is used to guide the negative pressure valve seat.

[0021] The fuel tank isolation valve of the present invention has the following beneficial effects compared with the prior art:

[0022] (1) A partition is provided in the valve body to separate the left cavity into a first cavity and a second cavity distributed downward and upward, and to separate the right cavity into a third cavity and a fourth cavity distributed downward and upward, the positive-pressure valve seat is located in the third cavity, and the negative-pressure valve unit is located in the second cavity. During the downward movement of the positive-pressure valve seat, the negative-pressure valve unit will not move downward with the positive-pressure valve seat, and there is no need to overcome the force of the negative-pressure valve unit. Therefore, the smaller the elastic force required by the positive-pressure spring, the smaller the size of the positive-pressure spring, which can reduce the cost. In addition, through the above design, the negative-pressure valve unit and the positive-pressure valve unit are not coaxial, and there is no need to align the negative-pressure valve unit with the positive-pressure valve seat, which makes the assembly of the device more difficult.

[0023] (2) An annular lip is provided on the outer side of the second air hole through the edge of the sealing gasket away from the positive pressure valve seat. The annular lip is used to seal with the partition to close the second air hole. When subjected to downward medium pressure, the sealing gasket is pushed downward to open the second air hole. When subjected to upward medium pressure, the annular lip is sealed with the partition, thereby improving the sealing effect, reliability and stability.

[0024] (3) An abutment ring is formed by the diaphragm at the edge of the first air hole protruding toward the second cavity, and the abutment ring is used to seal with the negative pressure valve unit to reduce the contact area between the negative pressure valve unit and the diaphragm, thereby making it easier to seal the negative pressure valve unit around the first air hole and the diaphragm, thereby improving the reliability and stability of the device;

[0025] (4) A first guide plate is provided at the bottom of the third cavity, and a second guide plate is provided at the bottom of the positive pressure valve seat. The inner diameter of the second guide plate is smaller than the inner diameter of the first guide plate. The positive pressure spring is located between the second guide plate and the first guide plate, so that the elastic force direction of the positive pressure spring remains along the axial direction of the positive pressure valve seat, so that the annular lip of the sealing gasket is more closely attached to the partition, thereby improving the sealing effect;

[0026] (5) A plurality of raising plates are provided at the bottom of the third cavity, and the plurality of raising plates are connected to the inner wall of the first guide plate. The positive pressure spring abuts between one end of the raising plate away from the bottom of the third cavity and the positive pressure valve seat. The raising plates can play a raising role, thereby reducing the compression amount of the positive pressure spring, so that the specification of the positive pressure spring can be shorter and the cost can be reduced. At the same time, the raising plates are connected to the inner wall of the first guide plate, which can increase the strength of the first guide plate and improve the reliability and stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a cross-sectional view of the fuel tank isolation valve of the present utility model;

[0029] Figure 2 It is a three-dimensional diagram of the fuel tank isolation valve of the present utility model;

[0030] Figure 3 It is a cross-sectional view of the valve body of the present utility model;

[0031] Figure 4 It is a three-dimensional diagram of the lower half of the valve body of the present invention;

[0032] Figure 5 A three-dimensional diagram of the upper half of the valve body of the present invention;

[0033] Figure 6 It is a three-dimensional diagram of the positive pressure valve unit of the present utility model;

[0034] Figure 7 This is a schematic structural diagram of the connection between the negative pressure valve seat and the solenoid valve unit of the present invention;

[0035] Figure 8 It is a three-dimensional diagram of the negative pressure valve seat of the present utility model;

[0036] Figure 9 It is a cross-sectional view of the solenoid valve unit of the present utility model;

[0037] Figure 10 This is a schematic diagram of the principle of the oil tank isolation valve of the utility model when working under positive pressure relief;

[0038] Figure 11 This is a schematic diagram of the principle of the oil tank isolation valve of the present utility model when working with negative pressure air supply.

[0039] Description of reference numerals: 1-valve body, 2-positive pressure valve unit, 3-negative pressure valve unit, 4-solenoid valve unit;

[0040] 11-left cavity, 111-first cavity, 112-second cavity, 12-right cavity, 121-third cavity, 1211-first guide plate, 122-fourth cavity, 13-partition plate, 131-first air hole, 132-second air hole, 133-abutting ring, 14-first channel, 15-second channel, 16-first rib plate, 17-heightening plate;

[0041] 21-positive pressure valve seat, 211-second guide plate, 22-positive pressure spring, 23-sealing gasket, 231-annular lip;

[0042] 31-negative pressure valve seat, 311-abutting seat, 312-sleeve tube, 3121-connecting cavity, 3122-mounting hole, 3123-mounting groove, 32-negative pressure spring;

[0043] 41-valve housing, 411-sliding hole, 412-positioning plate, 42-coil, 43-push rod, 431-shaft groove section, 44-connecting seat, 441-baffle, 442-guide cylinder. DETAILED DESCRIPTION

[0044] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0045] Reference Figures 1-11 As shown, the embodiment of the present utility model provides a fuel tank isolation valve, comprising a valve body 1, a positive pressure valve unit 2, a negative pressure valve unit 3 and a solenoid valve unit 4, wherein:

[0046] The valve body 1 includes a left cavity 11 and a right cavity 12 arranged in parallel on the left and right sides. A partition 13 is provided in the valve body 1 to separate the left cavity 11 into a first cavity 111 and a second cavity 112 distributed downward and upward, and to separate the right cavity 12 into a third cavity 121 and a fourth cavity 122 distributed downward and upward. The third cavity 121 is connected to the first cavity 111, the third cavity 121 is not connected to the second cavity 112, the fourth cavity 122 is connected to the second cavity 112, and the fourth cavity 122 is connected to the second cavity 112. The body 122 is not connected to the first cavity 111. The partition plate 13 is provided with a first air hole 131 connecting the first cavity 111 and the second cavity 112, and a second air hole 132 connecting the third cavity 121 and the fourth cavity 122. The third cavity 121 is connected to the first channel 14 for connecting to the carbon canister, and the second cavity 112 is connected to the second channel 15 for connecting to the fuel tank. The lower surface of the sealing gasket 23 and the top surface of the positive pressure valve seat 21 can be bonded by glue.

[0047] The positive pressure valve unit 2 includes a positive pressure valve seat 21, a positive pressure spring 22, and a sealing gasket 23. The positive pressure valve seat 21 is located in the third cavity 121. The two ends of the positive pressure spring 22 abut against the bottom of the third cavity 121 and the positive pressure valve seat 21, respectively. The lower surface of the sealing gasket 23 is connected to the surface of the positive pressure valve seat 21 away from the bottom of the first cavity 111. The upper surface of the sealing gasket 23 is used to seal with the partition 13 to close the second air hole 132.

[0048] The negative pressure valve unit 3 includes a negative pressure valve seat 31 and a negative pressure spring 32. The negative pressure valve seat 31 is connected to the solenoid valve unit 4. One end of the negative pressure spring 32 abuts against the solenoid valve unit 4, and the other end of the negative pressure spring 32 abuts against the negative pressure valve seat 31, so as to make the negative pressure valve seat 31 abut against the partition plate 13 to close the first air hole 131.

[0049] The solenoid valve unit 4 is installed at one end of the second cavity 112 away from the partition 13 and is connected to the negative pressure valve unit 3 to balance the elastic force of the negative pressure spring 32 through the magnetic field force;

[0050] in:

[0051] During positive pressure relief operation, after the medium enters the second chamber 112 and the fourth chamber 122 in sequence from the second channel 15, the medium pressure pushes the sealing gasket 23 and the positive pressure valve seat 21 downward, the sealing gasket 23 separates from the partition 13, and the second air hole 132 is opened. The solenoid valve unit 4 stops working, and the negative pressure valve seat 31 remains in contact with the partition 13 under the elastic force of the negative pressure spring 32. The medium enters the third chamber 121 from the second air hole 132 and is discharged into the carbon canister through the first channel 14.

[0052] When the negative pressure air replenishment is working, after the medium enters the third cavity 121 and the first cavity 111 in sequence from the first channel 14, the positive pressure valve seat 21 keeps the sealing gasket 23 in contact with the partition 13 under the elastic force of the positive pressure spring 22, and the medium pressure pushes the negative pressure valve unit 3 to move upward, and the negative pressure valve unit 3 detaches from the partition 13, opening the first air hole 131, and the medium enters the second cavity 112 from the first air hole 131 and is replenished to the oil tank through the first channel 14.

[0053] The fuel tank isolation valve proposed in this embodiment has a partition 13 provided in the valve body 1 to separate the left cavity 11 into a first cavity 111 and a second cavity 112 distributed downwardly and upwardly, and to separate the right cavity 12 into a third cavity 121 and a fourth cavity 122 distributed downwardly and upwardly. The positive pressure valve seat 21 is located in the third cavity 121, and the negative pressure valve unit 3 is located in the second cavity 112. During the downward movement of the positive pressure valve seat 21, the negative pressure valve unit 3 will not move downward with the positive pressure valve seat 21. Therefore, the smaller the elastic force required by the positive pressure spring 22, the smaller the size of the positive pressure spring 22, which can reduce the cost; in addition, through the above design, the negative pressure valve unit 3 and the positive pressure valve unit 2 are not coaxial, and there is no need to align the negative pressure valve unit 3 with the positive pressure valve seat 21, and the assembly difficulty of the device is lower; the medium pressure at the second air hole 132 acts on the middle part of the negative pressure valve seat 31, so that the force on the negative pressure valve seat 31 is more direct and concentrated, which can improve the reliability and stability of the device.

[0054] In some embodiments, an annular lip 231 is provided on one side edge of the sealing gasket 23 away from the positive pressure valve seat 21 and is located outside the second air hole 132. The annular lip 231 is used to seal and fit with the partition 13. The annular lip 231 is provided on one side edge of the sealing gasket 23 away from the positive pressure valve seat 21 and is located outside the second air hole 132. The annular lip 231 is used to seal and fit with the partition 13 to close the second air hole 132. When subjected to downward medium pressure, the sealing gasket 23 is pushed downward to open the second air hole 132. When subjected to upward medium pressure, the annular lip 231 is sealed and fit with the partition 13, thereby improving the sealing effect, reliability, and stability.

[0055] In some embodiments, the diaphragm 13 is formed with an abutment ring 133 at the edge of the first air hole 131 protruding toward the second cavity 112, and the abutment ring 133 is used to seal and fit with the negative pressure valve unit 3. The diaphragm 13 is formed with an abutment ring 133 at the edge of the first air hole 131 protruding toward the second cavity 112, and the abutment ring 133 is used to seal and fit with the negative pressure valve unit 3 to reduce the contact area between the negative pressure valve unit 3 and the diaphragm 13, thereby making it easier for the negative pressure valve unit 3 to be sealed and connected to the diaphragm 13 around the first air hole 131, thereby improving the reliability and stability of the device.

[0056] In some embodiments, a first guide plate 1211 is provided at the bottom of the third cavity 121, a second guide plate 211 is provided at the bottom of the positive pressure valve seat 21, the inner diameter of the second guide plate 211 is smaller than the inner diameter of the first guide plate 1211, and the positive pressure spring 22 is located between the second guide plate 211 and the first guide plate 1211. Because the first guide plate 1211 is provided at the bottom of the third cavity 121, the second guide plate 211 is provided at the bottom of the positive pressure valve seat 21, the inner diameter of the second guide plate 211 is smaller than the inner diameter of the first guide plate 1211, and the positive pressure spring 22 is located between the second guide plate 211 and the first guide plate 1211, the elastic force direction of the positive pressure spring 22 remains along the axial direction of the positive pressure valve seat 21, so that the annular lip 231 of the sealing gasket 23 fits more closely with the diaphragm 13, thereby improving the sealing effect.

[0057] In some embodiments, a plurality of raised plates 17 are provided at the bottom of the third cavity 121. The plurality of raised plates 17 are connected to the inner wall of the first guide plate, and the positive pressure spring 22 abuts between one end of the raised plate 17 away from the bottom of the third cavity 121 and the positive pressure valve seat 21. The raised plates 17 can act as a cushion, reducing the amount of compression of the positive pressure spring 22, thereby shortening the positive pressure spring 22 and reducing costs. Furthermore, the raised plates 17 are connected to the inner wall of the first guide plate 1211, thereby increasing the strength of the first guide plate 1211 and improving the reliability and stability of the device.

[0058] In some embodiments, the solenoid valve unit 4 includes a valve housing 41, a coil 42, and a push rod 43; the valve housing 41 is connected to the second cavity 112, and a sliding hole 411 is provided inside the valve housing 41; the coil 42 is provided at the top of the valve housing 41, and is used to magnetically attract the push rod 43 when energized; the push rod 43 is made of a magnetic material, is slidably installed in the sliding hole 411, and is connected to the negative pressure valve seat 31. The push rod 43 is slidably installed in the sliding hole 411, and the sliding hole 411 guides the sliding of the push rod 43. When the coil 42 is energized, the push rod 43 is magnetically attracted. The upward magnetic attraction force of the coil 42 is applied to the push rod 43 and transmitted to the negative pressure valve seat 31, balancing the downward elastic force of the negative pressure spring 32 on the negative pressure valve seat 31.

[0059] In some embodiments, the solenoid valve unit 4 also includes a positioning plate 412 located in the valve housing 41 and a connecting seat 44 located in the second cavity 112, the connecting seat 44 includes a baffle 441 and a guide cylinder 442; the push rod 43 abuts against the end of the baffle 441 away from the guide cylinder 442, and the baffle 441 can abut against the positioning plate 412; the guide cylinder 442 is connected to the end of the baffle 441 away from the coil 42, and the negative pressure spring 32 is sleeved on the push rod 43 and located in the guide cylinder 442. One end of the negative pressure spring 32 abuts against the baffle 441, and the other end of the negative pressure spring 32 abuts against the negative pressure valve seat 31. The baffle 441 abuts against the positioning plate 412, forming a support point for the negative pressure spring 32. The elastic force of the negative pressure spring 32 will not decrease as the push rod 43 rises. When the negative pressure is eliminated, the negative pressure spring 32 can drive the negative pressure valve seat 31 to descend and reset, thereby improving the stability and reliability of the device.

[0060] In some embodiments, the negative pressure valve seat 31 includes an abutment seat 311 and a sleeve 312, the abutment seat 311 is used to abut against the partition 13; the sleeve 312 is arranged at the top of the abutment seat 311, and a connecting cavity 3121 is provided inside the sleeve 312, and a mounting hole 3122 is provided on the top surface of the sleeve 312, and the diameter of the mounting hole 3122 is smaller than the diameter of the inner wall of the connecting cavity 3121, and an axis groove section 431 is provided at the end of the push rod 43 away from the coil 42, and the axis groove section 431 is provided in the mounting hole 3122, and the end of the push rod 43 is located in the connecting cavity 3121. The shaft groove section 431 is arranged in the mounting hole 3122, and the end of the push rod 43 is located in the connecting cavity 3121. The end diameter of the push rod 43 is larger than the diameter of the mounting hole 3122. The end of the push rod 43 is limited by the mounting hole 3122, so that the push rod 43 is connected to the negative pressure valve seat 31, and the push rod 43 and the negative pressure valve seat 31 act together.

[0061] In some embodiments, the outer wall of the sleeve 312 is provided with a mounting groove 3123, which connects the connecting cavity 3121 and the mounting hole 3122, and the width of the mounting groove 3123 is greater than the bottom diameter of the shaft groove section 431431. The outer wall of the sleeve 312 is provided with a mounting groove 3123, which connects the connecting cavity 3121 and the mounting hole 3122, and the width of the mounting groove 3123 is greater than the bottom diameter of the shaft groove section 431431. When installing the push rod 4343, the shaft groove section 431431 of the push rod 4343 is passed through the mounting groove 3123, and the end of the push rod 4343 is placed in the connecting cavity 3121, thereby improving the convenience of device installation and enhancing the reliability and stability of the device.

[0062] In some embodiments, a plurality of first ribs 16 are circumferentially disposed on the inner wall of the second cavity 112. The first ribs 16 extend from the inner wall of the second cavity 112 along the diameter of the second cavity 112. The ends of the first ribs 16 distal from the inner wall of the second cavity 112 serve to guide the negative pressure valve seat 31. While guiding the negative pressure valve seat 31, the first ribs 16 can also strengthen the diaphragm 13, preventing damage to the diaphragm 13 due to excessive force, thereby improving the reliability and stability of the device.

[0063] The working principle of the fuel tank isolation valve is:

[0064] During positive pressure relief operation, after the medium enters the second chamber 112 and the fourth chamber 122 in sequence from the second channel 15, the medium pressure pushes the sealing gasket 23 and the positive pressure valve seat 21 downward, the sealing gasket 23 separates from the partition 13, and the second air hole 132 is opened. The solenoid valve unit 4 stops working, and the negative pressure valve seat 31 remains in contact with the partition 13 under the elastic force of the negative pressure spring 32. The medium enters the third chamber 121 from the second air hole 132 and is discharged into the carbon canister through the first channel 14.

[0065] When the negative pressure air replenishment is working, after the medium enters the third cavity 121 and the first cavity 111 in sequence from the first channel 14, the positive pressure valve seat 21 keeps the sealing gasket 23 in contact with the partition 13 under the elastic force of the positive pressure spring 22, and the medium pressure pushes the negative pressure valve unit 3 to move upward, and the negative pressure valve unit 3 detaches from the partition 13, opening the first air hole 131, and the medium enters the second cavity 112 from the first air hole 131 and is replenished to the oil tank through the first channel 14.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fuel tank isolation valve, characterized in that: It includes a valve body, a positive pressure valve unit, a negative pressure valve unit and a solenoid valve unit, wherein: The valve body includes a left cavity and a right cavity arranged in parallel on the left and right sides. A partition is provided in the valve body to separate the left cavity into a first cavity and a second cavity distributed in a lower-upper direction, and to separate the right cavity into a third cavity and a fourth cavity distributed in a lower-upper direction. The third cavity is connected to the first cavity, and the fourth cavity is connected to the second cavity. The partition is provided with a first air hole connecting the first cavity and the second cavity, and a second air hole connecting the third cavity and the fourth cavity. The third cavity is connected to a first channel for connecting to a carbon canister, and the second cavity is connected to a second channel for connecting to a fuel tank. The positive pressure valve unit includes a positive pressure valve seat, a positive pressure spring, and a sealing gasket. The positive pressure valve seat is located in the third cavity. Two ends of the positive pressure spring abut against the bottom of the third cavity and the positive pressure valve seat, respectively. The lower surface of the sealing gasket is connected to the surface of the positive pressure valve seat away from the bottom of the first cavity. The upper surface of the sealing gasket is used to seal with the partition to close the second air hole. The negative pressure valve unit is located in the second cavity and is used to seal with the partition to close the first air hole; The solenoid valve unit is installed at one end of the second cavity away from the partition and is connected to the negative pressure valve unit; The medium enters the second cavity from the second channel, then enters the third cavity from the second air hole through the fourth cavity, and is discharged to the carbon canister through the first channel; or the medium enters the third cavity from the first channel, then enters the second cavity from the first air hole through the first cavity, and is replenished to the fuel tank through the first channel.

2. The fuel tank isolation valve according to claim 1, characterized in that: An annular lip located outside the second air hole is provided on an edge of one side of the sealing gasket away from the positive pressure valve seat, and the annular lip is used for sealingly fitting with the partition.

3. The fuel tank isolation valve according to claim 1, characterized in that: The partition is formed with an abutment ring at an edge of the first air hole that protrudes toward the second cavity, and the abutment ring is used to seal and fit with the negative pressure valve unit.

4. The fuel tank isolation valve according to claim 1, characterized in that: A first guide plate is provided at the bottom of the third cavity, a second guide plate is provided at the bottom of the positive pressure valve seat, the inner diameter of the second guide plate is smaller than the inner diameter of the first guide plate, and the positive pressure spring is located between the second guide plate and the first guide plate.

5. The fuel tank isolation valve according to claim 4, characterized in that: A plurality of raising plates are provided at the bottom of the third cavity, and the plurality of raising plates are connected to the inner wall of the first guide plate. The positive pressure spring abuts between one end of the raising plate away from the bottom of the third cavity and the positive pressure valve seat.

6. The fuel tank isolation valve according to claim 1, characterized in that: The negative pressure valve unit includes a negative pressure valve seat and a negative pressure spring. The negative pressure valve seat is connected to the solenoid valve unit. One end of the negative pressure spring abuts against the solenoid valve unit, and the other end of the negative pressure spring abuts against the negative pressure valve seat, so as to make the negative pressure valve seat abut against the partition, and the negative pressure valve seat closes the first air hole.

7. The fuel tank isolation valve according to claim 6, characterized in that: The solenoid valve unit includes a valve housing, a coil and a push rod; the valve housing is connected to the second cavity, and a sliding hole is provided inside the valve housing; the coil is provided at the top of the valve housing, and is used to magnetically attract the push rod after power is turned on; the push rod is made of magnetic material, and the push rod is slidably installed in the sliding hole and connected to the negative pressure valve seat.

8. The fuel tank isolation valve according to claim 7, characterized in that: The solenoid valve unit also includes a positioning plate located in the valve housing and a connecting seat located in the second cavity, the connecting seat includes a baffle and a guide cylinder; the push rod abuts against the end of the baffle away from the guide cylinder, and the baffle can abut against the positioning plate; the guide cylinder is connected to the end of the baffle away from the coil, and the negative pressure spring is sleeved on the push rod and located in the guide cylinder.

9. The fuel tank isolation valve according to claim 8, characterized in that: The negative pressure valve seat includes an abutment seat and a sleeve tube, the abutment seat is used to abut against the partition; the sleeve tube is arranged on the top of the abutment seat, and a connecting cavity is provided inside the sleeve tube. The top surface of the sleeve tube is provided with a mounting hole, and the diameter of the mounting hole is smaller than the diameter of the inner wall of the connecting cavity. The push rod is provided with an axis groove section at the end away from the coil, and the axis groove section is provided in the mounting hole, and the end of the push rod is located in the connecting cavity.

10. The fuel tank isolation valve according to any one of claims 6 to 9, characterized in that: A plurality of first ribs are circumferentially arranged on the inner wall of the second cavity. The first ribs extend from the inner wall of the second cavity along the diameter direction of the second cavity. One end of the first rib away from the inner wall of the second cavity is used to guide the negative pressure valve seat.

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