Fuel tank pressure regulator

Abstract

A fuel tank vent valve, comprising a venting device for regulating the discharge of fuel vapor from the fuel tank and allowing outside air to enter the fuel tank. The vent valve is used to regulate the pressure in the fuel tank.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 976,502, filed on February 14, 2020, under 35 U.S.C.§119(e), which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to fuel tank vent valves, and more particularly to an emission device for regulating the emission of fuel vapor from a fuel tank and allowing outside air to enter the fuel tank. More specifically, the present disclosure relates to a fuel tank pressure regulator including a solenoid - actuated fuel tank vent valve. Background Art

[0004] A vehicle fuel system includes a valve associated with a fuel tank and configured to vent pressurized or displaced fuel vapor from a vapor space in the fuel tank to a fuel vapor recovery canister located outside the fuel tank. The canister is designed to capture and store hydrocarbons entrained in the fuel vapor, which are displaced and generated in the fuel tank during typical vehicle fueling operations or otherwise discharged from the fuel tank.

[0005] The vapor recovery canister is also connected to a vehicle engine and a purge vacuum source. Typically, whenever the vehicle engine is running, a vacuum is applied to the vapor recovery canister through the purge vacuum source in an effort to draw the hydrocarbons captured and stored in the canister into the engine for combustion. Summary of the Invention

[0006] A fuel tank ventilation system according to the present disclosure includes a vapor flow controller for regulating the flow of fuel vapor between a fuel tank and a fuel vapor recovery system in a vehicle. The flow of fuel vapor is controlled to maintain the pressure of the fuel vapor in the fuel tank at a certain pressure level or within a certain pressure range.

[0007] In an exemplary embodiment, the tank ventilation system includes a fuel tank isolation valve positioned in an inner vapor transfer passage formed in a hollow flow management unit configured to direct fuel vapor back and forth between a fuel tank and a fuel vapor recovery canister on a vehicle. The inner vapor transfer passage is formed in a valve housing of a vapor conduit included in the hollow flow management unit to interconnect a tank passage formed in the flow management unit and communicating with the fuel tank and a canister passage formed in the flow management unit and communicating with the fuel vapor recovery canister. The vapor conduit includes a canister tube providing the canister passage, a canister tube providing the canister passage, and a valve housing providing the inner vapor transfer passage.

[0008] In an exemplary embodiment, the fuel tank isolation valve typically has a closed mode to prevent fuel vapor from flowing through an inner vapor transfer passage formed in the valve housing between the tank passage and the canister passage. The fuel tank isolation valve also has four different open modes to regulate the flow of fuel vapor through the inner vapor transfer passage between the fuel tank and the fuel vapor recovery canister. During fueling of the fuel tank, the first and second open modes are used to direct fuel vapor discharged from the fuel tank through the inner vapor transfer passage to the fuel vapor recovery canister. The third open mode is used to direct atmospheric air drawn by a vacuum in the fuel tank through the fuel vapor recovery canister to create a flow of fuel vapor through the inner vapor transfer passage into the fuel tank to relieve an undesired vacuum condition in the fuel tank. And the fourth open mode is used to direct high-pressure fuel vapor discharged from the fuel tank through the inner vapor transfer passage into the fuel vapor recovery canister to relieve an undesired overpressure condition in the fuel tank.

[0009] In an exemplary embodiment, the fuel tank isolation valve includes a fixed perforated partition and a movable multi-stage flow controller that is movable relative to the fixed perforated partition. The perforated partition is coupled to the valve housing to divide the inner vapor transfer passage such that a tank-side chamber leading to the tank passage is established on one side of the perforated partition and a canister-side chamber leading to the inner vapor transfer passage is formed on the other side of the perforated partition.

[0010] In an exemplary embodiment, the partition is perforated to form a first vent opening that fluidly interconnects the tank-side chamber and the canister-side chamber and a different second vent opening that also fluidly interconnects the tank-side chamber and the canister-side chamber. In the normally closed mode of the fuel tank isolation valve, both the first vent opening and the second vent opening are closed by the multi-stage flow controller. In the first open mode of the fuel tank isolation valve, during an early stage of fueling of the fuel tank, a small bleed stream of pressurized fuel vapor is allowed to flow from the fuel tank to the fuel vapor recovery canister through the first vent opening that is partially opened. In the second open mode of the fuel tank isolation valve, during a later stage of fueling of the fuel tank, a relatively large discharge stream of pressurized fuel vapor is allowed to flow from the fuel tank to the fuel vapor recovery canister through the relatively large second vent opening that is partially opened. In the third open mode of the fuel tank isolation valve, when an undesired vacuum condition exists in the fuel tank, pressurized fuel vapor from the fuel vapor recovery canister can flow to the fuel tank through the opened second vent opening while the first vent opening is closed. And in the fourth open mode of the fuel tank isolation valve, when an undesired overpressure condition exists in the fuel tank, pressurized fuel vapor from the fuel tank can flow to the fuel vapor recovery canister through a different third vent opening that is partially opened while the second vent opening is closed.

[0011] In an exemplary embodiment, the perforated separator is formed to include a central vent that establishes a first vent port configured to direct fuel vapor between a tank-side chamber and a canister-side chamber during fuel vapor transfer between a fuel tank and a fuel vapor recovery canister. The perforated separator is also formed to include several relatively smaller track vent holes that surround the central vent. The track vent holes cooperate to establish a second vent port configured to direct fuel vapor between the tank-side chamber and the canister-side chamber during fuel vapor transfer between the fuel tank and the vapor recovery canister.

[0012] In an exemplary embodiment, a multi-stage flow controller includes a tank-side vapor flow regulator, a canister-side vapor flow regulator, and a solenoid-actuated spring-biased movable armature mounted for movement within an armature receiving passage formed in the tank-side vapor flow regulator. Each of the movable armature, the tank-side vapor flow regulator, and the canister-side vapor flow regulator of the multi-stage flow controller is mounted to move independently relative to a fixed perforated separator within an inner vapor transfer passage formed in a valve housing of a hollow flow management unit along a single vertical axis extending through the valve housing to regulate the flow of fuel vapor between a fuel tank and a fuel vapor recovery canister through one or both of a first vent port and a second vent port formed in the fixed perforated separator.

[0013] In an exemplary embodiment, during the early and late stages of a tank refueling event, a fuel tank isolation valve changes in sequence from a normally closed mode closing a first vent port and a second vent port formed in a fixed perforated separator to a first open mode and then to a second open mode to vent discharged fuel vapor from the fuel tank to a fuel vapor recovery canister through a vapor conduit of a hollow flow management unit. In the first open mode of the fuel tank isolation valve, a solenoid is energized to move an armature upward along a single vertical axis, disengaging a downstream canister-side vapor flow regulator, thereby allowing a bleed flow of pressurized fuel vapor to flow through a tank pipe and a canister pipe through a central vent port hole (first vent port) formed in the perforated separator and a vapor flow hole formed in the canister-side vapor flow regulator to align with the central vent port hole when the canister-side vapor flow regulator engages the lower side of the perforated separator. In the second open mode of the fuel tank isolation valve, the solenoid is energized to further move the armature upward away from the fixed perforated separator, and this movement causes a lift flange included in the armature to engage a mating lift catch included in the tank-side vapor flow regulator to apply a lifting force to the remainder of the tank-side vapor flow regulator, thereby lifting a portion of the tank-side vapor flow regulator away from the top side of the perforated separator to disengage from the underlying perforated separator, allowing pressurized fuel vapor to flow additionally from the tank pipe to the canister pipe through a series of track vent port holes (second vent ports) formed in the perforated separator and arranged around the central vent port hole (first vent port), while the first vent port is partially open.

[0014] In an exemplary embodiment, during the formation of an undesired vacuum state in the fuel tank, the fuel tank isolation valve changes from its normally closed mode to a third open mode to allow fuel vapor including air from the atmosphere to flow from the fuel vapor recovery canister to the fuel tank through an inner vapor flow passage formed in a vapor conduit of the hollow flow management unit. In the third open mode of the fuel tank isolation valve, the solenoid is not energized, but fuel vapor moving to the inner vapor transfer passage in the canister pipe can reach the lower side of the tank-side vapor flow regulator through a track vent port hole (second vent port) formed in the perforated separator, and apply an upward lifting force on the tank side of the vapor flow regulator to cause the tank-side vapor flow regulator to move upward and disengage from the top perforated separator, allowing fuel vapor from the canister pipe to flow into the tank pipe through the open track vent port hole (second vent port) and then into the fuel tank to eliminate the undesired vacuum state in the fuel tank, while the first vent port remains closed through the cooperative action of the armature and the canister-side vapor flow regulator.

[0015] In an exemplary embodiment, during an undesired overpressure condition in the fuel tank, the fuel tank isolation valve changes from its normally closed mode to a fourth open mode to allow pressurized fuel vapor in the fuel tank to flow from the fuel tank to the fuel vapor recovery canister through an inner vapor transfer passage formed in a vapor conduit of the hollow flow management unit. In the fourth open mode, the solenoid is de-energized, but the pressurized fuel vapor present in the in-tank conduit from the fuel tank can reach the top side of the canister-side vapor flow regulator due to the partial opening of the first vent port, and a downward thrust is applied on the canister-side vapor flow regulator to move the canister-side vapor flow regulator downward to disengage from the lower side of the perforated separator, so that the overpressure fuel vapor from the fuel tank can flow to the canister conduit through the partially opened central vent port hole (second vent port), and then flow to the fuel vapor recovery canister to eliminate the undesired overpressure condition in the fuel tank.

[0016] Other features of the present disclosure will become apparent to those skilled in the art in view of the following detailed description of the exemplary embodiments, which illustrate the best mode currently contemplated for practicing the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] DETAILED DESCRIPTION With specific reference to the drawings, in which:

[0018] Figure 1 is a cross-sectional perspective view of a tank venting system according to the present disclosure, the tank venting system including a hollow flow management unit providing a vapor conduit, and further including a fuel tank isolation valve, the vapor conduit including a canister conduit coupled to a fuel vapor recovery canister, a tank conduit coupled to a fuel tank, and a valve housing formed to include a vertically extending inner vapor transfer passage that interconnects vapor conduction passages formed in the canister conduit and the tank conduit, the fuel tank isolation valve being positioned in the inner vapor transfer passage formed in the valve housing and showing the fuel tank isolation valve including a fixed perforated separator and a multi-stage flow controller, the fixed perforated separator being coupled to the valve housing, the multi-stage flow controller including components movable relative to the fixed perforated separator for normally closing, partially opening, and opening vent port holes formed in the perforated separator in different operating modes of the fuel tank isolation valve to regulate the flow of fuel vapor between the fuel tank and the fuel vapor recovery canister;

[0019] Figure 1A is an enlarged perspective view of the fixed perforated separator of the fuel tank isolation valve, showing how the plate is coupled to the valve housing;

[0020] Figure 2Ais an exploded perspective assembly view of components included in a fuel tank isolation valve together with portions of a hollow flow management unit, the portions of the hollow flow management unit cooperating to form a boundary of a vertical inner vapor transfer passage that houses the fuel tank isolation valve, and showing the portions including a valve housing, a top valve housing closure, and a bottom valve housing closure;

[0021] Figure 2B is another perspective assembly view showing the canister tube, valve housing, and tank tube of a vapor conduit of the hollow flow management unit and Figure 2A the components of the fuel tank isolation valve as shown in

[0022] Figure 2C and Figure 2D shows an exemplary snap - coupling process for attaching the top valve housing closure to the top end of the valve housing to cover a top opening into the inner vapor transfer passage formed in the valve housing;

[0023] Figure 3 is Figure 1 a side - sectional view of a tank venting system of

[0024] Figure 4 showing the fuel tank isolation valve in a normally - closed mode, and showing that the multi - stage flow controller includes: a canister - side vapor flow regulator positioned in a lower region of the canister - side chamber above a fixed perforated baffle; a tank - side vapor flow regulator positioned in the tank - side chamber below the fixed perforated baffle; and a solenoid - actuated spring - based movable armature extending downward from an upper region of the canister - side chamber through an armature receiving passage formed in the canister - side vapor flow regulator into the lower region of the canister - side chamber such that a distal tip of the movable armature closes a vapor flow orifice formed in the tank - side vapor flow regulator, and also showing that the multi - stage flow controller further includes an armature - moving solenoid having a coil positioned in the upper region of the canister - side chamber to surround an upper portion of the movable armature; Figure 3 is an enlarged view taken from the circled region of Figure 4B to show the normally - closed state of a first vent port and a second vent port formed in the fixed perforated baffle of the fuel tank isolation valve when the fuel tank isolation valve is in the normally - closed mode (see Figure 1A and Figure 4B shown in more detail);

[0025] Figure 4A is an enlarged view taken from the circled region of Figure 4 showing the normally - closed state of the first vent port and the second vent port formed in the fixed perforated baffle in the normally - closed mode of the fuel tank isolation valve;

[0026] Figure 4B is a magnified cross-sectional view taken along Figure 4 line 4B-4B, showing that the fixed perforated separator is formed to include a large-diameter central vent hole, the large-diameter central vent hole establishing a first vent hole and six relatively smaller elliptical arc-shaped track vent holes surrounding the central vent hole and establishing a second vent;

[0027] Figure 5 is similar to Figure 3 in view, showing the fuel tank isolation valve in a first open mode during the early stage of fueling the fuel tank. During the early stage of fueling the fuel tank, it allows a bleed flow of pressurized fuel vapor to flow from the tank passage through a first partially open first vent formed in the fixed perforated separator into the canister passage;

[0028] Figure 6 is a magnified view taken from the Figure 5 circular area, showing the first partial opening of the first vent;

[0029] Figure 6A is a magnified view taken from the Figure 6 circular area, showing the bleed flow of pressurized fuel vapor flowing around the distal tip of the movable armature through the first partially open first vent while the canister side vapor flow regulator remains engaged to the lower side of the fixed perforated separator to align the vapor flow hole formed in the canister side vapor flow regulator with the central vent hole formed in the fixed perforated separator;

[0030] Figure 7 is similar to Figure 3 and Figure 5 in view, showing the fuel tank isolation valve in a second open mode during the later stage of fueling the fuel tank. During the later stage of fueling the fuel tank, it allows a relatively large discharge flow of pressurized fuel vapor to flow from the tank passage through the second partially open first vent and the open second vent into the canister passage due to the upward movement of the tank side vapor flow regulator to disengage from the top side of the fixed perforated separator;

[0031] Figure 8 is a magnified view taken from the Figure 7 circular area when the fuel tank isolation valve is in the second open mode, showing the flow of the discharge flow of pressurized fuel vapor through the second partially open first vent and then into the canister passage;

[0032] Figure 9 is associated with Figure 3 , Figure 5 and Figure 7A similar cross-sectional view shows that during an undesired vacuum condition in the fuel tank, the fuel tank isolation valve is in a third open mode to draw in the atmosphere through the fuel vapor recovery canister to create a fuel vapor flow in the canister tube. The fuel vapor flow passes through an open second vent located within the inner vapor transfer passage and flows into the fuel tank through the tank tube to dissipate the undesired vacuum in the fuel tank;

[0033] Figure 10 is an enlarged view taken from the circled area of Figure 9 when the fuel tank isolation valve is in the third open mode, showing the second vent open while the first vent is closed;

[0034] Figure 11 is similar to Figure 3 、 Figure 5 、 Figure 7 and Figure 9 a similar cross-sectional view showing that during an undesired overpressure condition in the fuel tank, the fuel tank isolation valve is in a fourth open mode to allow pressurized fuel vapor to flow from the tank tube into the canister tube through a third partially open first vent formed in a fixed perforated separator; and

[0035] Figure 12 is an enlarged view taken from the circled area of Figure 11 when the fuel tank isolation valve is in the fourth open mode. DETAILED DESCRIPTION

[0036] The fuel tank venting system 10 includes a hollow flow management unit 11 and a fuel tank isolation valve 12 associated with the unit 11, as Figure 1 shown. The hollow flow management unit 11 includes a vapor conduit 14 that fluidly connects the fuel tank 16 and the fuel vapor recovery canister 18 such that fuel vapor can flow back and forth between the fuel tank 16 and the fuel vapor recovery canister 18 through a plurality of channels formed in the vapor conduit 14 included in the hollow flow management unit 11. The fuel tank venting system 10 is configured to control the flow of air and fuel vapor between the fuel tank 16 and an emissions control system that includes the fuel vapor recovery canister 18, as shown. The system 10 is used on a vehicle (not shown) that includes an engine 20 and a purge vacuum source (not shown) coupled to the engine 20 and the canister 18, such as Figure 3 shown.

[0037] The fuel tank isolation valve 12 is configured in accordance with the present disclosure to normally isolate the fuel tank 16 from the fuel vapor recovery canister 18 to prevent fuel vapor from flowing between the tank 16 and the canister 18. The fuel tank isolation valve 12 is configured to have four open modes to allow for temporary fuel vapor flow between the tank 16 and the canister 18 during four different tank events.

[0038] In a vehicle with a normal internal combustion engine, fuel vapors from the fuel tank are directly discharged into the surrounding atmosphere. Directly discharging fuel vapors into the surrounding atmosphere can be harmful to people and / or the environment.

[0039] However, in a partial hybrid electric vehicle (PHEV), the internal combustion engine included in the vehicle operates intermittently, and thus, when not in use (i.e., when the engine is not in use), the fuel tank system is often isolated from the atmosphere. Isolating the system from the atmosphere can reduce harmful emissions to the surrounding environment, but may create a need to control / regulate the fuel vapors in the system.

[0040] Therefore, the fuel vapors in the fuel tank can be at a higher pressure or a lower vacuum pressure than in a normal engine, which can make it challenging to open the fuel system line when ready for use. Additionally, if the increased pressure in the fuel tank is not released, the fuel tank may be damaged or even explode. The fuel tank isolation valve 12 controls the flow of fuel vapors and air between the fuel tank 16 and the fuel vapor recovery canister 18, which is used to store pressurized fuel vapors to release the pressure built up in the fuel tank 16 at different stages.

[0041] In Figure 1 、 Figure 3 and Figures 4 to 4B , the fuel tank isolation valve 12 is shown in a normally closed mode to block the flow of fuel vapors between the fuel tank 16 and the fuel vapor recovery canister 18. In Figure 5 、 Figure 6 and Figure 6A , the fuel tank isolation valve 12 is shown in a first open mode to discharge some of the displaced fuel vapors from the fuel tank 16 during the early stage of fueling the fuel tank, when a person uses a fuel dispensing pump nozzle (not shown) to discharge fuel into the filler neck leading to the fuel tank. In Figure 7 and Figure 8 , the fuel tank isolation valve 11 is shown in a second open mode to discharge more of the displaced fuel vapors from the fuel tank 16 during the later stage of fueling the fuel tank. In Figure 9 and Figure 10 , the fuel tank isolation valve 12 is shown in a third open mode to relieve an undesirable vacuum condition in the fuel tank 16. In Figure 11 and Figure 12 , the fuel tank isolation valve 12 is shown in a fourth open mode to relieve an undesirable overpressure condition in the fuel tank 16.

[0042] The fuel tank isolation valve 12 regulates the flow of fuel vapors through the vapor conduit 14 to, according to Figure 3 、 Figure 5 、 Figure 7 、 Figure 9 and Figure 11The predetermined pressure target proposed regulates the pressure of the fuel vapor within the fuel tank 16. The fuel tank isolation valve 12 includes a fixed perforated partition 22 and a multi-stage flow controller 24. The fixed perforated partition 22 is installed in the vapor conduit 14, and the multi-stage flow controller 24 is installed in the vapor conduit 14, beside the perforated partition 22 and movable relative to the perforated partition 22 to regulate the flow of fuel vapor through separate first vent ports 221 and second vent ports 222 formed in the perforated partition 22. The fuel tank isolation valve 12 further includes a solenoid 26, which is used in conjunction with the multi-stage flow controller 24 during a fuel tank refueling event. The solenoid 26 can be energized during the first open mode and the second open mode of the fuel tank isolation valve 12 as shown in Figure 5 and Figure 7 .

[0043] The vapor conduit 14 of the hollow flow management unit 11 is formed as shown in Figure 1 to include: a horizontally extending tank pipe 33, connected to the fuel tank 16 via a tank conduit 13; a horizontally extending canister pipe 35, connected to the fuel vapor recovery canister 18 via a canister conduit 15; and a valve housing 34, providing a vertically extending inner vapor transfer passage 34P that fluidly connects a tank passage 33P formed in the tank pipe 33 with a canister passage 35P formed in the canister pipe 35. As shown in Figure 1 , the vapor conduit 14 further includes a top valve housing closure 28 for closing the open top end of the valve housing 34 and a bottom valve housing closure 30 for closing the open bottom of the valve housing 34.

[0044] As shown in Figure 1 and Figure 4 , the perforated partition 22 of the fuel tank isolation valve 12 is positioned within the inner vapor transfer passage 34P formed in the valve housing 34. The perforated partition 22 is connected to the vapor conduit 14 to separate the inner vapor transfer passage 34P, thereby defining a tank-side chamber 38 above the perforated partition 22 for conducting fuel vapor between the tank passage 33P and the first vent ports 221 and second vent ports 222 formed in the perforated partition 32, and a canister-side chamber 39 below the perforated partition 22 for conducting fuel vapor between the canister passage 35P and the first vent ports 221 and second vent ports 221.

[0045] The multi-stage flow controller 24 is as shown in Figure 1 , Figure 3 and Figure 4The structure shown generally engages the perforated partition 22 to close the first vent 221 and the second vent 222 formed in the perforated partition 22, thereby preventing fuel vapor from flowing from the tank pipe 33 to the canister pipe 35 through the inner vapor transmission passage 34P formed in the valve housing 34 of the vapor conduit 14 of the hollow flow control unit 11, such that the fuel tank 16 is generally fluidly isolated from the fuel vapor recovery canister 18. However, the multi-stage flow controller 24 is configured in accordance with the present disclosure to disengage from the perforated partition 22 in several different ways as shown in Figure 6 , Figure 8 , Figure 10 and Figure 12 shown, during (1) Figure 6 and Figure 8 in the early and late stages of the fueling operation of the fuel tank 16 shown, (2) Figure 10 when an undesired vacuum condition occurs in the fuel tank 16 shown, and (3) Figure 12 when an undesired overpressure condition occurs in the fuel tank 16 shown, independently establishing the first vent 221 through the central vent hole 221 formed in the perforated partition 22 and also establishing the second vent 222 and around the central vent hole 221 through several track vent holes 222a to 222f (see Figure 4B ) formed in the perforated partition 22 to regulate the flow of fuel vapor in the vapor conduit 14 between the fuel tank 16 and the fuel vapor recovery canister 18.

[0046] The multi-stage flow controller 24 includes a tank-side vapor flow regulator 24T positioned above the perforated partition 22 in the tank-side chamber 38, the perforated partition 22 being formed in the inner vapor transmission passage 34P of the valve housing 34, as Figure 1 and Figure 4 suggested, to transfer fuel vapor to and from the fuel tank 16 via the tank pipe 33 connected to the fuel tank 16. The multi-stage flow controller 24 further includes a canister-side vapor flow regulator 24C positioned below the perforated partition 22 in the canister-side chamber 39, the perforated partition 22 being formed in the inner vapor transmission passage 34P of the valve housing 34, to transfer fuel vapor to and from the fuel vapor recovery canister 18 via the canister pipe 35 connected to the fuel vapor recovery canister 18. Each of the tank-side vapor flow regulator 24T and the canister-side vapor flow regulator 24C is aligned to move up and down relative to the perforated partition 22 along a single vertical axis 34A extending through the inner vapor transmission passage 34P formed in the vapor conduit 14.

[0047] By aligning each of the tank-side vapor flow regulator 24T and the canister-side vapor flow regulator 24C along a single vertical axis 34A in the inner vapor transfer passage 34P, the space required to accommodate the fuel tank isolation valve 12 can be reduced. The arrangement of the regulators 24T, 24C along the axis 34A can also provide benefits in manufacturing and packaging.

[0048] The multi-stage flow controller 24 further includes a spring-biased movable armature 24A, which is operatively coupled to the solenoid 26 and is arranged to extend into the inner vapor transfer passage 34P as Figure 1 and Figure 3 shown, and moves relative to the fixed perforated partition 22 along a single vertical axis 34A extending through the tank-side chamber 38, the central vent hole 221 formed in the perforated partition 22, and the canister-side chamber 39. When the fuel tank isolation valve 12 is in the normally closed mode as Figure 1 、 Figure 3 and Figure 4 shown, the movable armature 24A cooperates with the tank-side vapor flow regulator 24T and the canister-side vapor flow regulator 24C to block the fuel vapor from passing through the central vent 221 and the track vent hole 222 formed in the perforated partition 22, so that the fuel vapor cannot flow through the vapor conduit 14 between the fuel tank 16 and the fuel vapor recovery canister 18, and thus the fuel tank 16 is normally isolated from the vapor recovery canister 18.

[0049] The tank-side vapor flow regulator 24T and the canister-side vapor flow regulator 24C are configured to move relative to the fixed perforated partition 22 in the inner vapor transfer passage 34P to close, partially open, and open the vents 221, 222 formed in the perforated partition 22 in response to changes in the fuel vapor pressure present in the inner vapor transfer passage 34P and the fuel tank 16. The movable armature 24A is normally spring-biased by a spring 40 to move towards the canister-side vapor flow regulator 24C, and when the solenoid 26 is energized, the movable armature 24A is operatively connected to the solenoid 26 to move upward from the canister-side vapor flow regulator 24C. The movable armature 24A includes a distal tip 24AT, which is arranged to extend into the inner vapor transfer passage 34P and moves in the inner vapor transfer passage 34P in response to the thrust generated by the armature movement spring 40 and the actuation of the solenoid 26 to assume various positions in the inner vapor transfer passage 34P, so as to cooperate with the canister-side vapor flow regulator 24C to close or partially open the first vent 221 formed in the perforated partition 22.

[0050] As Figure 1 、 Figure 3 、 Figure 4 and Figure 4AAs shown, when the tank-side vapor flow regulator 24T engages the top side 22T of the perforated partition 22 to close the second vent 222 and the distal tip 24AT of the movable armature closes the vapor flow hole 24CO formed in the tank-side vapor flow regulator 24C, while the tank-side vapor flow regulator 24C engages the lower side 220 of the perforated partition 22, the normally closed mode of the fuel tank isolation valve 12 is established. As Figure 3 and Figure 4 shown, the solenoid 26 is de-energized in the first open mode, while the armature moving spring 40 is arranged to engage the top end of the movable armature 24A and act against the top valve housing closure 28 to yieldably move the movable armature 24A downwardly to engage the distal tip 24AT with the tank-side vapor flow regulator 24C and close the vapor flow hole 24CO formed in the tank-side vapor flow regulator 24C.

[0051] As Figure 5 、 Figure 6 and Figure 6A shown, during the early stage of fuel tank refueling, when the solenoid 26 is energized to lift the distal tip 24AT of the movable armature 24A upwardly to disengage from the tank-side vapor flow regulator 24C, thereby opening the vapor flow hole 24CO, while the tank-side vapor flow regulator 24T remains engaged with the top side 22T of the perforated partition 22 and the tank-side vapor flow regulator 24C remains engaged with the lower side 22U of the perforated partition 22, such that the bleed flow (B) of the pressurized fuel vapor can flow from the tank passage 33P through the inner vapor transfer passage 34P, through the first vent 221 which is narrowly opened in the first partially open state of the first vent 221 as shown in Figure 6A to establish the first open mode of the fuel tank isolation valve 12. This allows the displaced fuel vapor to start flowing from the fuel tank 16 through the inner vapor transfer passage 34P to the fuel vapor recovery canister 18.

[0052] As Figure 7 and Figure 8 shown, during the later stage of fuel tank refueling, when the solenoid 26 is further energized to lift the tank-side vapor flow regulator 24T upwardly away from the perforated partition 22 to open the second vent 222 and move the distal tip 24AT of the movable armature 24A from the first vent 221 to a position above and away from the top side 22T of the perforated partition 22 to further open the first vent 221, so as to change the first vent 221 to Figure 8The second partially open state of the first vent 221 shown in FIG. 0, such that a relatively large discharge stream (D) of pressurized fuel vapor can flow from the tank passage 33P through the inner vapor transfer passage 34P, through the open second vent 222, and through the more widely open first vent 221, establishing the second open mode of the fuel tank isolation valve 12. As Figure 4 and Figure 6 shown, the movable armature 24A includes an elongate body 24B extending between a top end and a distal tip 24AT, and a radially outwardly extending lift flange 24F cantilevered to the elongate body 24B.

[0053] The tank-side vapor flow regulator 24T is formed to include a radially inwardly extending lift catch 24LC as also shown in Figure 4 and Figure 6 FIG. 0. When the solenoid 26 is energized, due to the lifting force applied by the upward movement of the lift flange 24F of the movable armature 24A to the underside of the lift catch 24LC of the tank-side vapor flow regulator 24T as shown in Figure 7 and Figure 8 FIG. 0, the movable armature 24A moves upward along the central vertical axis 34A to compress the armature bias spring 40 between the top valve housing closure 28 and the top end of the movable armature 24A. This lifting force causes the tank-side vapor flow regulator 24T to move upward to open the second vent 222, and causes the distal tip 24AT of the movable armature 24A to move further away from the perforated partition 22 to establish the second partially open state of the first vent 221 as shown in Figure 8 FIG. 0.

[0054] In the normally closed mode, no part of the movable armature 24A contacts or engages the regulator 24T to close the track vents 221, 222 of the plate 22. Instead, the spring 54 biases the regulator 24T to engage the top side 22T of the plate 22. The regulator 24T has an opening such that the lift flange 24F of the movable armature 24A does not engage any part of the tank-side vapor flow regulator 24T. Only when the valve 12 is in the second open mode does the movable armature 24A engage the radially inwardly extending lift catch 24LC of the regulator 24T to compress the spring 54 and open the track vents 221, 222.

[0055] As Figure 9 and Figure 10As shown, a third opening mode of the fuel tank isolation valve 12 is established to direct fuel vapor from the fuel vapor recovery canister 18 through the inner vapor transfer passage 34P into the fuel tank 16, thereby alleviating any undesired vacuum condition that may occur in the fuel tank 16. In this third opening mode, the relatively high fuel vapor pressure present in the canister side chamber 39 acts on the tank side vapor flow regulator 24T through the second vent port 222 to apply an upward thrust to the lower side of the tank side vapor flow regulator 24T, thereby moving the tank side vapor flow regulator 24T upward in the tank side chamber 38 to disengage from the top side 22T of the perforated partition 22, thus opening the second vent port 222. At the same time, the solenoid 26 is de-energized to allow the armature movement spring 40 associated with the movable armature 24A to move the movable armature 24A downward to extend the distal tip 24AT into the first vent port 221 to close the vapor restriction hole 24CO formed in the canister side vapor flow regulator 24C, while the canister side vapor flow regulator 24C engages the lower side 22U of the perforated partition 22.

[0056] As Figure 11 and Figure 12 shown, a fourth opening mode of the fuel tank isolation valve 12 is established to direct pressurized fuel vapor from the fuel tank 16 through the inner vapor transfer passage 34P to the fuel vapor recovery canister 24C to alleviate the overpressure condition formed in the fuel tank 16. In this fourth opening mode, the relatively high fuel vapor pressure present in the tank side chamber 38 acts on the canister side vapor flow regulator 24C through the partially opened first vent port 221 to move the canister side vapor flow regulator 24C downward away from the lower side 22U of the perforated partition 22, thereby expanding the opening in the first vent port 221 to present a third partially opened state as Figure 12 shown, while the tank side vapor flow regulator 24T remains engaged to the top side 22T of the perforated partition 22.

[0057] As described above, the fuel tank isolation valve 12 may be important for regulating the pressure of fuel vapor in the system of a hybrid vehicle. As Figure 3 shown, the fuel tank isolation valve 12 is normally closed to prevent fuel vapor from flowing from the tank 16 to the canister 18. The fuel tank isolation valve 12 has four different opening modes (the first opening mode as Figure 5 shown, the second opening mode as Figure 7 shown, the third opening mode as Figure 9 shown, and the fourth opening mode as Figure 11 shown) to regulate the flow of fuel vapor between the fuel tank 16 and the canister 18 based on different states of the system.

[0058] In the case of an overpressure condition, valve 12 changes to a fourth open mode to allow a large amount of pressure to be released from fuel tank 16. Conversely, if a vacuum condition exists in fuel tank 16, fuel tank isolation valve 12 can change to a third open mode to relieve the undesired vacuum condition. Once the vehicle switches to using engine 20, fuel tank isolation valve 12 can change to one of a first open mode, a second open mode, and a fourth open mode to allow fuel vapor to flow from fuel tank 16 through canister 18 and to the engine for combustion with the fuel.

[0059] During refueling of the fuel tank, it may also be important to release the accumulated pressure of the fuel vapor in the fuel tank. When a person starts using a fuel dispensing pump nozzle to discharge fuel into the filler neck leading to the fuel tank, fuel tank isolation valve 12 changes from a closed mode to a first open mode to discharge some of the displaced fuel vapor from fuel tank 16. After refueling begins and fuel is discharged into fuel tank 16 at a constant rate, fuel tank isolation valve 12 changes to a second open mode to discharge more of the displaced fuel vapor.

[0060] In Figure 1 a cross-sectional perspective view of the tank venting system 10 is provided to show that the vapor conduit 14 of the hollow flow management unit 11 is arranged to fluidly connect the fuel tank 16 and the fuel vapor recovery canister 18, and the fuel tank isolation valve 12 is positioned within an inner vapor transfer passage 34P formed in the vapor conduit 14 of the hollow flow management unit 11. According to the present disclosure, during four open modes of operation, fuel tank isolation valve 12 is operable to control the vapor flow between fuel tank 16 and fuel vapor recovery canister 18 through the vapor conduit 14 of the hollow flow management unit 11.

[0061] The vapor conduit 14 of the hollow flow management unit 11 includes: a canister tube 35 that is connected to the fuel vapor recovery canister 18 at its outer end via a canister conduit 15; a tank tube 33 that is connected to the fuel tank 16 at its outer end via a tank conduit 13; a vertical valve housing 34 that is arranged to be fluidly connected to each of the inner ends of the canister tube 35 and the tank tube 33, and is sized to accommodate the fuel tank isolation valve 12 therein, as Figure 1 shown. A top valve housing closure 28 is connected to the top end of the valve housing 34 of the vapor conduit 14, while a bottom valve housing closure 30 is connected to the opposite bottom end of the valve housing 34.

[0062] The fuel tank isolation valve 12 includes a perforated partition 22 that is arranged to divide the interior region of the vertical valve housing 34 of the vapor conduit 14 into a canister side chamber 39 that is in communication with the canister tube 35 and an overlying tank side chamber 38 that is in communication with the tank tube 33, as Figure 2B shown. The perforated partition 22 is formed to include: as Figure 1A and Figure 2BThe central vent hole 221 of the first vent 221 is established and six orbital vent holes 222a to 222f of the second vent 222 are established and surround the central vent hole 221, as Figure 3 shown in the upper region 38U of the tank side chamber 38 where the armature moving solenoid 26 and the multi-stage flow controller 24 are installed. The multi-stage flow controller 24 includes a movable armature 24A, and the movable armature 24A is as Figure 1 , Figure 3 and Figure 4 shown is normally arranged in the closed mode of the fuel tank isolation valve 12 to prevent fuel vapor from flowing through the central vent hole 221 and the orbital vent holes 222 formed in the perforated partition 22 included in the fuel tank isolation valve 12, so that the fuel vapor recovery tank 18 is normally isolated from the fuel tank 16 until (1) the tank refueling activity starts as Figure 4 shown; (2) the tank vacuum exceeds the predetermined vacuum level as Figure 9 shown; or (3) the tank pressure exceeds the predetermined pressure level as Figure 11 shown.

[0063] The perforated partition 22 is shown in Figure 1A and is arranged to divide the inner vapor transmission channel 34P into the upper tank side chamber 38 and the lower tank side chamber 39 as Figure 3 shown. The perforated partition 22 is formed to include a circular central vent hole 221 centered on the central vertical axis 34A and six arcuate orbital vent holes 222a to 222f arranged to surround the circular central vent hole 221 and in a radially spaced relationship with the central vertical axis 34A and in a circumferentially spaced relationship with each other. The perforated partition 22 is installed at a fixed position in the inner region of the vertical valve housing 34 of the vapor conduit 14.

[0064] As Figure 2A shown, the fuel tank isolation valve 12 includes a perforated partition 22, an armature moving solenoid 26 and a multi-stage flow controller 24. The multi-stage flow controller 24 includes: a tank side vapor flow regulator 24T, including a sealing ring 50, a top hat-shaped spring cap 52 and a large diameter compression (vacuum) spring 54; an armature biasing spring 40; a movable armature 24A; and a tank side vapor flow regulator 24C. The tank side vapor flow regulator 24C includes a narrow diameter compression (pressure) spring 60, a spring cap 62 and an annular seal 64.

[0065] In Figure 2BA disassembled perspective view of the components is provided to show two sub - assemblies SAT and SAC included in the fuel tank isolation valve 12 and the vapor conduit 14 of the hollow flow management unit 11. A portion of the tank - side chamber housing 341 of the valve housing 34 is cut away to reveal that the perforated partition 22 included in the fuel tank isolation valve 12 is formed to include a central vent hole 221, and the central vent hole 221 is surrounded by a series of track vent holes 222a - 222f. In Figure 2B it is shown that the top vent device sub - assembly SAT included in the fuel tank isolation valve 12 is mounted in a downward direction into an upward - opening tank - side chamber 38 formed in the tank - side housing 341 of the vertical valve housing 34 of the vapor conduit 14 included in the hollow flow management unit 11. In Figure 2B it is also shown that the bottom vent device sub - assembly SAC included in the fuel tank isolation valve 12 is mounted in an upward direction into a downward - opening tank - side chamber 39 formed in the tank - side chamber housing 342 of the vertical valve housing 34 of the vapor conduit 14 included in the hollow flow management unit 11.

[0066] In Figure 2C and Figure 2D it is shown the snap - fit connection assembly process for attaching the top valve housing closure 28 of the hollow flow management unit 11 to the tank - side housing 341 of the valve housing 34 of the hollow flow management unit 11. As Figure 2C shown, the retaining bar 71 included in the external snap - connector 72 on the housing 28B of the top valve housing closure 28 first rides on the inclined ramp 73 of the external locking lug 74. The external locking lug 74 is included in the valve housing 34 of the hollow flow management unit 11 and is coupled to the outer surface of the tank - side housing 341 during the downward movement of the top valve housing closure 28 relative to the tank - side housing 341. As Figure 2D shown, the retaining bar 71 of the external snap - connector 72 of the top valve housing closure 28 has moved to disengage from the inclined ramp 73 and find the correct position below the external locking lug 74 where it engages with the downward - facing movement - blocking surface 75 of the external locking lug. The movement - blocking surface 75 of the external locking lug is positioned below the inclined ramp 73 of the external locking lug 74. In an exemplary embodiment, a bottom seal ring 28R1 and a top seal ring 28R2 seal between the top valve housing closure 28 and the tank - side housing 341 of the valve housing 34.

[0067] The bottom valve housing closure 30 includes a base 30B and a seal ring 30R. The base 30B and the seal ring 30R engage the tank - side chamber housing 342 of the valve housing 34 to enclose the tank - side chamber 39. The spring 60 of the tank - side vapor flow regulator 24C engages the base 30B of the bottom valve housing closure 30 to bias the spring cap 62 with an O - ring seal 64 into engagement with the lower side 22U of the perforated partition 22.

[0068] As Figure 3 shown, the fuel tank isolation valve 12 is in its normally closed mode to prevent fuel vapor from flowing through the vapor conduit 14 between the fuel tank 16 and the fuel vapor recovery canister 18. The top vent device subassembly SAT and the bottom vent device subassembly SAC, which are included in the fuel tank isolation valve 12 and shown in Figure 2B , have been installed in the vertical valve housing 34 of the vapor conduit 14 of the hollow flow management unit 11 such that the top vent device subassembly SAT and the bottom vent device subassembly SAC are aligned with each other along a single vertical axis 34A extending through the center of the perforated partition 22 to cooperate with the perforated partition 22 to establish the fuel tank isolation valve 12 according to the present disclosure. The fuel tank isolation valve 12 is generally used to prevent all flow of fuel vapor through the internal region of the vertical valve housing 34 of the vapor conduit 14 of the hollow flow management unit 11 between the tank tube 33 and the canister tube 35.

[0069] As Figure 4 shown, the top vent device subassembly SAT, which is included in the fuel tank isolation valve 12 and shown in FIG. 2, has been installed in the vertical valve housing 34 of the vapor conduit 14 such that the downwardly extending tip 24AT of the movable armature 24A extends along the single vertical axis 34A into the first vent 221 established and formed in the perforated partition 22 by the central vent hole 221 (see Figure 4B ), and such that the sealing ring 50 of the tank side vapor flow regulator 24T engages the annular outer peripheral region of the top side 22T of the perforated partition 22 to prevent fuel vapor from passing through the second vent 222 formed by the six orbital vent holes 222a to 222f (see Figure 4B ) surrounding the central vent hole 222, and it is shown that the second vent 222 formed by the inner edge of the O-ring seal 64 of the canister side vapor flow regulator 24C engages the downwardly facing surface on the distal tip 24AT of the movable armature 24A, and the outer edge of the O-ring seal 64 of the canister side vapor flow regulator 24C engages the downwardly facing surface on the annular inner peripheral region of the lower side 22U of the perforated partition 22, which surface surrounds the central vent hole 221 to prevent fuel vapor from passing through the central vent hole 221 formed in the perforated partition 22. For example, in Figure 4B shown are the circular central vent hole 221 and the six circumferentially spaced apart arcuate orbital vent holes 222a to 222f formed in the perforated partition 22 of the fuel tank isolation valve 12.

[0070] When the fuel tank isolation valve 12 is in the state as shown in Figure 5 , Figure 6 and Figure 6ADuring the first opening mode shown, during refueling of the fuel tank 16 by an operator (not shown) using the fuel dispensing pump nozzle, a first stage of refueling depressurization of the fuel tank 16 occurs. The multi-stage flow controller 24 is shown in a solenoid-actuated first open configuration to allow a small bleed flow (B) of pressurized fuel vapor to flow from the tank passage 33P formed in the tank tube 33 through the central vent hole 221 formed in the perforated separator 22, through the small-diameter central vapor flow holes 24CO in each of the O-ring seal 64 and the spring cap 62 of the tank-side vapor flow regulator 24C, to generate a magnetic field in the movable armature 24A associated with the tank-side vapor flow regulator 24T in response to actuation of the solenoid 26, to move the armature 24A upward from the closed position engaged with the Figure 4 O-ring seal 64 of the tank-side vapor flow regulator 24C shown in Figure 6 to an open position separated from the O-ring seal 64 of the tank-side vapor flow regulator 24C shown in

[0071] During Figure 6 an enlarged view taken from the circular area of Figure 5 is provided to show the small bleed flow (B) of pressurized fuel vapor, which bleed flow passes from the tank passage 33P formed in the tank tube 33 through the space in the large-diameter compression (vacuum) spring 54 of the tank-side vapor flow regulator 24T, and then through the central valve hole 221 formed in the perforated separator 22. And then, due to the upward movement of the movable armature 24A relative to the perforated separator 22 caused by actuation of the solenoid 26 to disengage from the annular seal 64 of the tank-side vapor flow regulator 24C, the small bleed flow (B) can pass through the now-open vent vapor flow holes 24CO in each of the annular seal 64 and the mating spring cap 62 of the tank-side vapor flow regulator 24C, and then through the space in the small-diameter compression (pressure) spring 60 of the tank-side vapor flow regulator 24C into the tank passage 35P formed in the tank tube 35.

[0072] When the fuel tank isolation valve 12 is in the second opening mode as shown in Figure 7 and Figure 8 a second stage of refueling depressurization of the fuel tank 16 occurs. The multi-stage flow controller 24 is shown in a pressure-actuated second open configuration to allow the pressure of the pressurized fuel vapor present in the tank passage 33P to increase from the Figure 5 first pressure (P1) shown in Figure 7The higher second pressure (P2) shown in the figure then vents the pressurized fuel vapor from the tank passage 33P into the tank passage 35P to cause the top hat shaped spring cap 52 and the associated O-ring seal 50 to move upward away from the perforated baffle 22 to compress the large diameter compression (vacuum) spring 54 and open the normally closed six track vent holes 222a to 222f formed in the perforated baffle 22, while the center vent hole 221 in the perforated baffle 21 remains open so that a larger volume of pressurized fuel vapor can be discharged from the fuel tank 16 to the fuel vapor recovery canister 24C via the inner vapor transfer passage 34P of the vapor conduit 14 of the hollow flow management unit 11.

[0073] exist Figure 8 Provided from Figure 7 2 is an enlarged view taken from the encircled area of ​​​​the tank side vapor flow to show that during refueling of the fuel tank 16, the pressurized fuel vapor flows from the tank passage 33P through the central vent hole 221 and the track vent holes 222 formed in the perforated partition 22 into the tank passage 35P. The solenoid 26 is energized to move the movable armature 24A upward. This action causes the lifting flange 24F of the movable armature 24A to engage the underside of the lifting catch 24LC of the top hat-shaped spring cap 52 to apply a lifting force to the top hat-shaped spring cap 52, thereby moving the sealing ring 50 included in the tank side vapor flow regulator 24T upward to cause the sealing ring 50 to disengage the perforated partition 22 below and open the six track vent holes 222a to 222f formed in the perforated partition 22, while the solenoid 26 remains energized.

[0074] exist Figure 9 , an undesirable vacuum condition is shown to be generated in the fuel tank 16 when no tank refueling activity is being performed. The multi-stage flow controller 24 is shown in a vacuum-actuated third open configuration after a vacuum (e.g., negative pressure) condition has been formed in the fuel tank 16, wherein the tank-side vapor flow regulator 24T has moved upward to disengage the underlying perforated baffle 22, thereby opening the six track vent holes 222a to 222f formed in the perforated baffle 22, thereby allowing fuel vapor including atmospheric air entrained with fuel droplets desorbed from the fuel vapor recovery canister 18 to flow into and through the canister passage 35P formed in the canister tube 35, then through the six track vent holes 222a to 222f, and through the tank passage 33P formed in the canister tube 33, and through the tank conduit 13 into the fuel tank 16 to alleviate the undesirable vacuum condition in the fuel tank 16.

[0075] exist Figure 11 Provided from Figure 92 to illustrate that after the solenoid 26 has been further energized, the flow of fuel vapor from the tank passage 35P through the six track vent holes 222a to 222f formed in the perforated partition 22 effectively applies an upward lifting force to the top hat-shaped spring cap 52 and the matching sealing ring 50 of the tank-side vapor flow regulator 24T. This lifting force causes those components to move in an upward direction relative to the hollow flow management unit 11 to compress the large diameter compression (vacuum) spring 54, thereby opening the six track vent holes 222a to 222f, while the center vent hole 221 remains closed to allow such fuel vapor to flow through the tank passage 33P formed in the tank tube 33 into the fuel tank 16, thereby alleviating the undesirable vacuum condition in the fuel tank 16.

[0076] exist Figure 11 2 is shown during an undesirable overpressure condition in the fuel tank 16, when no tank refueling activity is occurring. After the pressure of the fuel vapor present in the fuel tank 16 has risen above a predetermined maximum pressure level, the multi-stage flow controller 24 is shown in a pressure activated fourth open configuration, wherein the tank side vapor flow regulator 24C has moved downwardly to disengage the overlying perforated baffle 22, thereby opening a portion of the central vent hole 221 formed in the perforated baffle 22, a portion of the central vent hole 221 extending around the cylinder 24B included in the movable armature 24A, thereby allowing pressurized fuel vapor (P3) to flow from the fuel tank 16 to the fuel vapor recovery canister 18 via the tank tube 33, the tank tube 35 and the vertical valve housing 34 of the vapor conduit 14 included in the hollow flow management unit 11.

[0077] exist Figure 12 Provided from Figure 11 2 is an enlarged view of the circled area of ​​​​the tank to show that the pressurized fuel vapor flow (P3) flows from the tank passage 33P through the central vent hole 221 formed in the perforated partition 22 to establish the first vent 221 to apply a downward thrust (F) to the top side of the spring cap 52 of the tank side vapor flow regulator and the matching annular seal 50. This downward thrust (F) pushes those components in the downward direction relative to the hollow flow control unit 11 to compress the small diameter compression (pressure) spring 60, thereby opening most of the central valve hole 221, while the six track vent holes 221a to 221f forming the second vent 222 remain closed to allow such pressurized fuel vapor (P3) to flow through the tank passage 35P formed in the tank tube 35, enter the fuel vapor recovery tank 18, and release the undesirable overpressure state in the fuel tank 16.

[0078] The tank ventilation system 10 according to the present disclosure includes the following Figure 1The hollow flow management unit 11 and the fuel tank isolation valve 12 shown. According to the present disclosure, the fuel tank isolation valve 12 has a normally closed mode and four open modes.

[0079] The hollow flow management unit 11 includes a vapor conduit 14, which is formed to include a canister passage 35P and a tank passage 33P. The canister passage 35P is adapted to be fluidly connected to a fuel vapor recovery canister 18, and the tank passage 33P is adapted to be fluidly connected to a fuel tank 16, as Figure 1 shown. The vapor conduit 14 is further formed to include an inner vapor transfer passage 34P, which is arranged to fluidly interconnect the canister passage 35P and the tank passage 33P, so as to transfer fuel vapor flowing out from the fuel tank 16 associated with the tank passage 33P to the fuel vapor recovery canister 18 associated with the canister passage 35P through the tank passage 33P and the canister passage 35P, and transfer fuel vapor flowing from the fuel vapor recovery canister 18 to the fuel tank 16 through the canister passage 35P and the tank passage 33P.

[0080] The fuel tank isolation valve 12 includes a perforated partition 22 as Figure 1 and Figure 1A shown. In Figure 4 it is shown that the perforated partition 22 is installed at a fixed position in the inner vapor transfer passage 34P formed in the vapor conduit 14 to separate the inner vapor transfer passage 34P, thereby establishing a tank-side chamber 38 communicating with the tank passage 33P and a canister-side chamber 39 communicating with the canister passage 35P, so that the first side surface 22T of the fixed perforated partition 22 intercepts the fuel vapor flowing from the tank passage 33P to the canister passage 35P in the inner vapor transfer passage 34P, and the opposite second side surface 22U of the fixed perforated partition 22 intercepts the fuel vapor flowing from the canister passage to the tank passage 33P in the inner vapor transfer passage 34P. The fixed perforated partition 22 is formed as Figure 1A 、 Figure 4 and Figure 4B shown to include a first vent 221, which leads to the tank-side chamber 38 of the inner vapor transfer passage 34P through the first side surface 22T and also leads to the canister-side chamber 39 of the inner vapor transfer passage 34P through the second side surface 22U. The fixed perforated partition 22 is also formed to include a second vent 22, which is separated from the first vent 221 and leads to the tank-side chamber 38 through the first side surface 22T and also leads to the canister-side chamber 39 through the second side surface 22U.

[0081] The fuel tank isolation valve 12 further includes a multi-stage flow controller 24, which is configured according to the present disclosure as Figure 2A shown for enabling as Figure 1 、 Figure 3 andFigure 4 The first vent 221 and the second vent 222 formed in the fixed perforated partition 22 as shown are normally closed. The first vent 221 and the second vent 222 are normally closed to prevent fuel vapor from flowing through each of the first vent 221 and the second vent 222, thereby establishing a normally closed mode of the fuel tank isolation valve 12 such that fuel vapor cannot flow through the vapor conduit 14 between the fuel tank 16 and the fuel vapor recovery canister 18, so as to normally isolate the fluid communication between the fuel tank 16 and the fuel vapor recovery canister 18.

[0082] The multi-stage flow controller 24 is also configured as shown in the present disclosure as Figure 5 to provide a temporary restriction of the pressurized fuel vapor present in the tank-side chamber 38 from flowing into the canister-side chamber 39 through the first vent 221 formed in the fixed perforated partition 22 to initiate a partial opening of the first vent 221, thereby achieving a first restriction on the flow of the pressurized fuel vapor through the first vent 221 characterized by the first partially opened state of the first vent 221, while the second vent 222 remains closed, thereby establishing a first opening mode of the fuel tank isolation valve 12 as shown in Figure 6 and Figure 6A During the early stage of refueling the fuel tank 16, while the pressure of the pressurized fuel vapor in the tank passage 33P remains below a relatively high second pressure (P2), the multi-stage flow controller causes the bleed flow (B) of the pressurized fuel vapor to be discharged from the tank-side chamber 38 into the canister-side chamber 39 through the first vent 221 that is first partially opened and formed in the fixed perforated partition 22, such that the pressurized fuel vapor is allowed to enter the canister-side chamber 39 to increase the pressure present in the canister-side chamber 39.

[0083] The multi-stage flow controller 24 is also configured as shown in the present disclosure as Figure 7 to provide a temporary opening of the second vent 222 formed in the fixed perforated partition 22 while restricting the flow of the pressurized fuel vapor through the first vent 221 characterized by the second partially opened state of the first vent 221 formed in the fixed perforated partition 22, so as to achieve a different second restriction on the flow of the pressurized fuel vapor through the first vent 221, thereby establishing as shown in Figure 8The second opening mode of the fuel tank isolation valve 12 shown in the figure. During a relatively late stage of refueling the fuel tank 16, after the pressure of the pressurized fuel vapor present in the tank passage 33P has risen to at least a relatively high second pressure (P2), the multi-stage flow controller causes a relatively large discharge flow (D) of the pressurized fuel vapor to be discharged from the tank-side chamber 38 to the canister-side chamber 39 via the second partially opened first vent 221 and the second vent 222 formed in the fixed perforated partition 22, so that a relatively large volume of the pressurized fuel vapor flowing into the tank-side chamber 39 in the tank passage 33P can be discharged through the first vent 221 and the second vent 222 formed in the fixed perforated partition 22, flow into the canister passage 35P through the inner vapor transfer passage 34P, and then flow to the fuel vapor recovery canister 18 to dissipate the pressure in the fuel tank 16.

[0084] According to the present disclosure, as Figure 9 shown, the multi-stage flow controller 24 is further configured to temporarily open the second vent 222 formed in the fixed perforated partition 22 while the first vent 221 is closed, thereby establishing a third opening mode of the fuel tank isolation valve 12 during an undesired vacuum state formed in the fuel tank 16 as Figure 10 shown in the figure. Due to the formation of a vacuum state in the fuel tank 16, this action allows fuel vapor including atmospheric air to flow from the fuel vapor recovery canister 18 to the fuel tank 16 through the second vent 221 formed in the fixed perforated partition 22 via the vapor conduit 14, so that the fuel vapor flowing in the canister passage 35P flows into the tank passage 33P through the inner vapor transfer passage 34P and then into the fuel tank 16 to dissipate the undesired vacuum state in the fuel tank 16.

[0085] The multi-stage flow controller 24 is also configured as shown in the figure according to the present disclosure, during a period when an undesired overpressure state is formed in the fuel tank 16, after the pressure of the pressurized fuel vapor present in the tank passage 33P has risen above the relatively high second pressure (P2) to as Figure 11 shown in the figure Figure 12After at least the third pressure (P3) shown, the multi-stage flow controller 24 provides a temporary restriction to the flow of pressurized fuel vapor present in the tank-side chamber 38 through the first vent 221 formed in the fixed perforated partition 22 to achieve a third restriction on the flow of pressurized fuel vapor through the first vent 221 characterized by the third partially open state, while the second vent is closed to establish a fourth open mode of the fuel tank isolation valve 12. The third restriction is different from each of the first and second restrictions on the flow of pressurized fuel vapor through the first vent 221. This action causes the overpressure fuel vapor to flow through the third partially open first vent 221 formed in the fixed perforated partition 22 and be discharged from the tank-side chamber 38 to the canister-side chamber 39, such that the overpressure fuel vapor flowing in the tank passage 33P flows into the canister passage 33P through the inner vapor transfer passage 34P and then flows to the fuel vapor recovery canister 18 to dissipate the unwanted overpressure condition in the fuel tank 16.

[0086] As Figure 1 shown, the vapor conduit 14 includes a canister tube 35 and a tank tube 33. The canister tube 35 is formed to include a canister passage 35P and is adapted to be coupled to the fuel vapor recovery canister 18 via a canister conduit 15 at an outer end of the canister tube 35. The tank tube 33 is formed to include a tank passage 33P and is adapted to be coupled to the fuel tank 16 via a tank conduit 13 at an outer end of the tank tube 33. The vapor conduit 14 further includes a valve housing 34 that is formed to include an inner vapor transfer passage 34P. The valve housing 34 is coupled to the inner ends of each of the canister tube 35 and the tank tube 33 to place a canister-side chamber 39 of the inner vapor transfer passage 34P in fluid communication with the canister passage 35P and a tank-side chamber 38 in fluid communication with the tank passage 33P.

[0087] As Figure 1As shown, the multi-stage flow controller 24 includes a tank-side vapor flow regulator 24T and a canister-side vapor flow regulator 24C, as well as a movable armature 24A operatively connected to a solenoid 26. The tank-side vapor flow regulator 24T is mounted to move toward and away from a fixed perforated partition 22 relative to the valve housing 34 within a tank-side chamber 38 of the inner vapor transfer passage 34P to open and close a second vent 222 formed in the fixed perforated partition 22. The canister-side vapor flow regulator 24C is mounted to move toward and away from the tank-side vapor flow regulator 24T relative to the valve housing 34 within a canister-side chamber 39 of the inner vapor transfer passage 34P to regulate the flow of pressurized fuel vapor through a first vent 221 formed in the fixed perforated partition 22. The movable armature 24A is mounted within an armature receiving passage 24ARC formed in the tank-side vapor flow regulator 24T to move up and down between a closed position and several open positions relative to the fixed perforated partition 22. When the fuel tank isolation valve 12 is in the normally closed mode, the movable armature 24A extends through the first vent 221 in the closed position to engage the canister-side vapor flow regulator 24C, while the canister-side vapor flow regulator 24C engages a second side surface 22U of the fixed perforated partition 22 to close the first vent 221. The movable armature 24A disengages from the canister-side vapor flow regulator 24C in the several open positions to allow the pressurized fuel vapor present in the tank-side chamber 38 to flow through the first vent 221 into the canister-side chamber 39. In the normally closed mode, no portion of the movable armature 24A contacts or engages the regulator 24T to close the track vent holes 221, 222 of the plate 22.

[0088] The canister-side vapor flow regulator 24C is formed to include Figure 2A and Figure 2B a vapor flow hole 24CO as shown in, when the canister-side vapor flow regulator 24C is disposed within the canister-side chamber 39 to engage a second side surface 22U of the fixed perforated partition 22 as shown in Figure 5 and Figure 6 the vapor flow hole 24CO communicates with the first vent 221 to accommodate the pressurized fuel vapor discharged through the first vent 221. The movable armature 24A includes a distal tip 24A which, when the fuel tank isolation valve 12 is in the normally closed mode, is set to engage the canister-side vapor flow regulator 24C to close the vapor flow hole 24CO to prevent the pressurized fuel vapor present in the first vent 221 from being discharged into the canister-side chamber 39, and when the fuel tank isolation valve 12 is in a first open mode as shown in Figure 6A the distal tip 24A is spaced a first distance from the vapor flow hole 24CO, and when the fuel tank isolation valve 12 is in a mode as shown in Figure 8In the second opening mode shown, the distal tip 24A is separated from the vapor flow hole 24CO by a second distance greater than the first distance.

[0089] When the fuel tank isolation valve 12 is in the first opening mode as shown in Figure 6A the distal tip 24AT of the movable armature 24A is arranged to extend into the first vent 221, and when the fuel tank isolation valve 12 is in the second opening mode as shown in Figure 8 the distal tip 24AT is arranged to be located outside the first vent 221. The distal tip 24AT of the movable armature 24A is arranged to extend into the first vent 221, so that when the fuel tank isolation valve 12 is in the first opening mode as shown in Figure 6A it is in a first position in the first vent 221, and when the fuel tank isolation valve 12 is in the fourth opening mode as shown in Figure 12 the distal tip 24AT of the movable armature 24A is in a different second position in the first vent 221.

[0090] The distal tip 24AT of the movable armature 24A includes a downward-facing bottom surface, and the downward-facing bottom surface faces the vapor flow hole 24CO formed in the tank-side vapor flow regulator 24C. When the fuel tank isolation valve 12 is in the first opening mode as shown in Figure 5 , Figure 6 and Figure 6A the downward-facing bottom surface of the distal tip 24AT is arranged to be located adjacent to the first side surface 24T of the fixed perforated partition 22 and is separated from the first side surface 24T by a first distance, and when the fuel tank isolation valve 12 is in the fourth opening mode as shown in Figure 11 and Figure 12 the downward-facing bottom surface of the distal tip 24AT is arranged to be located adjacent to the second side surface 22U of the fixed perforated partition 22 and is separated from the first side surface 22T by a second distance greater than the first distance.

[0091] The movable armature 24A includes a distal tip 24AT, and when the movable armature 24A is in the closed position, the distal tip 24AT is arranged to engage the tank-side vapor flow regulator 24C to close the vapor flow hole 24CO formed in the tank-side vapor flow regulator 24C to communicate with the first vent 221 and the tank-side chamber 39. When the fuel tank isolation valve 12 is in the normally closed mode and the third opening mode, the tank-side vapor flow regulator 24C moves to engage the second side surface 22U of the fixed perforated partition 22 as shown in Figure 4 and Figure 4A and Figure 10 This action causes the movable armature 24A and the tank-side vapor flow regulator 24C to cooperate to close the first vent 221.

[0092] The movable armature 22A further includes a top end that is arranged to be located in a spaced-apart relationship with the distal tip 24AT as shown. Figure 2A The multi-stage flow controller 24 also includes a compression spring 40 having a first end that engages the top end of the movable armature 24A and an opposite second end. The opposite second end of the compression spring 40 normally acts against the top valve housing closure 28 of the hollow flow management unit 11 to urge the movable armature 24A in the inner vapor transfer passage 34P toward the tank-side vapor flow regulator 24C to close the distal tip 24AT to form a vapor flow hole 24CO in the tank-side vapor flow regulator 24C as shown in Figure 4 and Figure 10 and

[0093] The movable armature 24A further includes an elongate body 24B and a radially outwardly extending lifting flange 24F. The elongate body 24B is arranged to interconnect the top end and the distal tip 24AT. The lifting flange 24F has an inner end that is coupled to the elongate body 24B as shown in Figure 2A . The lifting flange 24F is arranged to extend radially outwardly from the central vertical axis 34A that extends through the body 24B and the first vent 221. The tank-side vapor flow regulator 24T also includes a tank-side compression spring 54 having a first end and an opposite second end. The first end engages the movable tank-side closures 50, 52. The second end normally acts against the hollow flow management unit 11 to urge the movable tank-side closures 50, 52 to engage the first side surface 22T of the fixed perforated partition 22 to close the second vent 222 as shown in Figure 1 and Figure 3 and

[0094] In the normally closed mode, the elongated body 24B, the distal tip 24AT, and the lifting flange 24F do not engage the top-hat-shaped spring cap 52. Instead, the spring 54 biases the top-hat-shaped spring cap 52 into engagement with the top side 22T of the plate 22. The top-hat-shaped spring cap 52 has an opening such that the lifting flange 24F of the movable armature 24A does not engage any part of the tank-side vapor flow regulator 24T. Only when the valve 12 is in the second open mode does the movable armature 24A engage the radially inwardly extending lifting latch 24LC of the top-hat-shaped spring cap 52 to compress the spring 54 and open the track vent holes 221, 222.

[0095] The movable tank-side closures 50, 52 are top-hat-shaped and also include an annular base 52B that is coupled to the sleeve 52S and is arranged to extend radially outwardly away from the sleeve 52S to face toward the annular valve seat 34V formed in the valve housing 34. The first end of the tank-side compression spring 54 engages the annular base of the movable tank-side closure. The tank-side compression spring 54 is partially coiled to surround the sleeve.

[0096] When the fuel tank isolation valve 12 is in the first open mode, the distal tip 24AT of the movable armature 24A is positioned in a first position of several open positions in the tank-side chamber 38 outside the first vent 221 as Figure 5 , Figure 6 and Figure 6A shown, to position the distal tip 24AT at a first distance from the tank-side vapor flow regulator 24C, to be in a spaced-apart relationship with the vapor flow hole 24CO, and adjacent to the second side surface 22U of the fixed perforated baffle 22, to establish a first restriction on the flow of fuel vapor through the first vent 221. This position of the distal tip 24AT establishes a first partially open state of the first vent 221.

[0097] When the fuel tank isolation valve 12 is in the second open mode, the distal tip 24AT of the movable armature 24A is located at an elevated second position of several open positions in the tank-side chamber 39 as Figure 7 and Figure 8 shown, to position the distal tip 24AT at a second distance greater than the first distance from the tank-side vapor flow regulator 24C while the tank-side vapor flow regulator 24C remains engaged with the second side surface 22U of the fixed perforated baffle 22, to allow the pressurized fuel vapor exiting the first vent 221 to flow through the vapor flow hole 24CO formed in the tank-side vapor flow regulator 24C, to establish a second restriction on the flow of pressurized fuel vapor through the first vent 221. This position establishes a second partially open state of the first vent 221.

[0098] When the fuel tank isolation valve 12 is in the normally closed mode, the tank-side vapor flow regulator 24T is arranged as Figure 9 and Figure 10 shown to engage the first side surface 22T of the fixed perforated separator 22 to close the second vent 222 formed in the fixed perforated separator 22. When the fuel tank isolation valve 12 is in the third open mode, the tank-side vapor flow regulator 24T is arranged to disengage from the first side surface 22T of the fixed perforated separator 22.

[0099] When the fuel tank isolation valve 12 is in the fourth open mode, the can-side vapor flow regulator 24C is arranged as Figure 11 and Figure 12 shown to disengage from the second side surface 22U of the fixed perforated separator 22, while the distal tip 24AT of the movable armature 24A is located in the first vent 221 formed in the fixed perforated separator 22, and the distal tip 24AT is in the third of several open positions to establish a third restriction to the flow of pressurized fuel vapor through the first vent 221, while the tank-side vapor flow regulator 24T is arranged to engage the first side surface 22T of the fixed perforated separator 22 to close the second vent 222 formed in the fixed perforated separator 22. This position establishes a third partially open state of the first vent 221.

[0100] Each of the tank-side vapor flow regulator 24T and the can-side vapor flow regulator 24C is arranged to move relative to the valve housing 34, the fixed perforated separator 22, and relative to each other along a single vertical axis 34A. The single vertical axis 34A extends through the tank-side chamber 38, the first vent 221 formed in the fixed perforated separator 22, and the can-side chamber 39.

[0101] The multi - stage flow controller 24 further includes a movable armature 24A which is mounted to move relative to the valve housing 34 and the tank - side vapor flow regulator 24T and towards and away from the fixed perforated partition 22 within an armature receiving passage 24ARC formed in the tank - side vapor flow regulator 24T. The tank - side vapor flow regulator 24C includes a fuel vapor flow restrictor which is formed to include a small - diameter vapor flow orifice 24CO and a sealing ring 64. The small - diameter vapor flow orifice 24CO is relatively smaller in size than the central vent orifice 221 established by the first vent 221. The sealing ring 64 is arranged to surround the small - diameter vapor flow orifice 24CO and extends towards the second side surface 22U of the fixed perforated partition 22. When the tank - side vapor flow regulator 24C moves within the tank - side chamber 39 to engage the second side surface 22U of the fixed perforated partition 22, the small - diameter vapor flow orifice 24CO is positioned to lead to a fuel vapor vent passage 24VP formed in the tank - side vapor flow regulator 24C to communicate with the tank - side chamber 39 formed in the valve housing 34, and is also positioned to communicate with the central vent orifice 221 established by the central vent orifice 221 formed in the fixed perforated partition 22, thereby guiding the pressurized fuel vapor from the tank - side chamber 38 through the central vent orifice 221, the small - diameter vapor flow orifice 24CO, and the fuel - vapor vent passage 24VP to the tank - side chamber 39.

[0102] The movable armature 24A includes a distal tip 24AT which is arranged to move relative to the fixed perforated partition 22 between a projected position, a retracted position, and an intermediate position. The distal tip 24AT is arranged to face downwardly towards the vapor flow orifice 24CO formed in the tank - side vapor flow regulator 24C.

[0103] In the projected position, the movable armature 24A extends into the central vent orifice 221 formed in the fixed perforated partition 22 to engage the sealing ring 64 included in the tank - side vapor flow regulator 24C as shown in Figure 4 and Figure 10 When the fuel tank isolation valve 12 is in the normally - closed mode, this engagement closes the small - diameter vapor flow orifice 24CO formed in the fuel vapor flow restrictor to prevent the flow of pressurized fuel vapor present in the tank - side chamber 39 and the central vent orifice 221 formed in the fixed perforated partition 22 through the small - diameter vapor flow orifice 24CO formed in the tank - side vapor flow regulator 24C, and when the fuel tank isolation valve 12 is in the third open mode, to prevent the flow of fuel vapor present in the tank - side chamber 39 through the first vent 221 formed in the tank - side vapor flow regulator 24C and the fixed perforated partition 22.

[0104] In the retracted position, the movable armature 24A is withdrawn from the central vent hole 221 formed in the fixed perforated partition 22 as shown in Figure 7 and Figure 8 When the movable armature 24A is in the second open mode, this withdrawal allows a relatively large flow of the pressurized fuel vapor discharge flow (D) to pass from the tank-side chamber 38 through the first vent 221 and the second vent 222, and through the small-diameter vapor flow hole 24CO, and along the fuel vapor vent passage 24VP into the canister-side chamber 39, and is transported via the canister passage 35P to the fuel vapor recovery canister 24C.

[0105] As shown in Figure 5 and Figure 6 the intermediate position is located between the extended position and the retracted position. When the fuel tank isolation valve 12 is in the first open mode, the arrangement of the distal tip 24AT in the intermediate position causes the bleed flow (B) of the pressurized fuel vapor to be discharged from the tank-side chamber 38 into the canister-side chamber 39 via the first vent 221.

[0106] Each of the movable armature 24A, the tank-side vapor flow regulator 24T, and the canister-side vapor flow regulator 24C is arranged to move relative to the valve housing 34, the fixed perforated partition 22, and relative to each other along a single vertical axis 34A, which extends through the tank-side chamber 38, the first vent 221 formed in the fixed perforated partition 22, the small-diameter vapor flow hole 24CO formed in the fuel vapor flow restrictor of the canister-side vapor flow regulator 24C, and the canister-side chamber 39. During a mode change of the fuel tank isolation valve 12 between each of the first open mode, the second open mode, the third open mode, and the fourth open mode and the normally closed mode, each of the tank-side vapor flow regulator 24T, the movable armature 24A, and the canister-side vapor flow regulator 24C is mounted in the inner vapor transfer passage 34P formed in the valve housing 34 for independent movement relative to each other and relative to the fixed perforated partition 22.

[0107] The fixed perforated partition 22 of the fuel tank isolation valve 12 is coupled to the valve housing 34 of the vapor conduit 14 and is arranged to be entirely located within the inner vapor transfer passage 34P formed in the valve housing 34. The first vent 221 is established by the central vent hole 221 formed in the fixed perforated partition 22, and the second vent 222 is established by a series of track vent holes 222a to 222f formed in the fixed perforated partition 22 and arranged around the central vent hole 221.

[0108] In a hybrid vehicle, the internal combustion engine included in the vehicle runs intermittently, and the fuel tank system is isolated from the surrounding atmosphere, which may create a need for controlling / regulating fuel vapor in the control / regulation system. Compared to other vehicles, hybrid vehicles typically also have a relatively small fuel tank. When the vehicle is using the electric motor (i.e., the engine is not in use), the pressure of the fuel vapor in the fuel tank may increase.

[0109] This may make it challenging to open the fuel system pipeline when ready for use. Additionally, if the increased pressure in the fuel tank is not released, the fuel tank may be damaged or even explode. The fuel tank isolation valve 12 controls the flow of fuel vapor and air between the fuel tank 16 and the fuel vapor recovery canister 18 for storing pressurized fuel vapor to release the pressure built up in the fuel tank 16 at different stages.

[0110] The fuel tank isolation valve 12 isolates the canister 18 in the PHEV from the fuel tank 16. As Figure 3 shown, in the normally closed mode, the valve 12 blocks the flow of fuel vapor from the tank 16 to the canister 18.

[0111] The fuel tank isolation valve 12 has four different opening modes (the first opening mode as Figure 5 shown, the second opening mode as Figure 7 shown, the third opening mode as Figure 9 shown, and the fourth opening mode as Figure 11 shown) to regulate the flow of fuel vapor between the fuel tank 16 and the canister 18 based on different states of the system. In the case of an overpressure state, the valve 12 changes to the fourth opening mode to allow a large amount of pressure to be released from the fuel tank 16.

[0112] Conversely, if there is a vacuum state in the fuel tank 16, the fuel tank isolation valve 12 can change to the third opening mode to relieve the undesired vacuum state. Once the vehicle switches to using the engine 20, the fuel tank isolation valve 12 can change to one of the first opening mode, the second opening mode, and the fourth opening mode to allow the fuel vapor to flow from the fuel tank 16 through the canister 18 and flow to the engine to burn with the fuel.

[0113] During refueling of the fuel tank, it may also be important to release the accumulated pressure of the fuel vapor in the fuel tank. When people start using the fuel dispensing pump nozzle to discharge fuel into the filler neck leading to the fuel tank, the fuel tank isolation valve 12 changes from the closed mode to the first opening mode to discharge some of the displaced fuel vapor from the fuel tank 16. After refueling starts and fuel is discharged into the fuel tank 16 at a constant rate, the fuel tank isolation valve 12 changes to the second opening mode to discharge more of the displaced fuel vapor.

[0114] In the normally closed position, no part of the movable armature 24A contacts or engages the regulator 24T to close the track vent holes 221, 222 of the plate 22. Instead, the spring 54 biases the regulator 24T to engage the top side 22T of the plate 22. The regulator 24T has an opening such that the lifting flange 24F of the movable armature 24A does not engage any part of the tank side vapor flow regulator 24T. Only when the valve 12 is in the second open mode does the movable armature 24A engage the radially inwardly extending lifting latch 24LC of the regulator 24T to compress the spring 54 and open the track vent holes 221, 222.

[0115] The following numbered clauses include expected and non - limiting embodiments:

[0116] Clause 1. A tank venting system, comprising:

[0117] A hollow flow management unit including a vapor conduit formed to include a canister passage, a tank passage, and an inner vapor transfer passage, the canister passage being adapted to be fluidly coupled to a fuel vapor recovery canister, the tank passage being adapted to be fluidly coupled to a fuel tank, the inner vapor transfer passage being arranged to fluidly interconnect the canister passage and the tank passage to transfer fuel vapor flowing from the fuel tank associated with the tank passage through the tank passage and the canister passage to the fuel vapor recovery canister associated with the canister passage, and to transfer fuel vapor flowing from the fuel vapor recovery canister through the canister passage and the tank passage to the fuel tank; and

[0118] A fuel tank isolation valve including a fixed perforated partition mounted in the inner vapor transfer passage formed in the vapor conduit to partition the inner vapor transfer passage, thereby establishing a tank - side chamber in communication with the tank passage and a canister - side chamber in communication with the canister passage, such that a first side surface of the fixed perforated partition intercepts fuel vapor flowing in the inner vapor transfer passage from the tank passage to the canister passage, and a second opposite side surface of the fixed perforated partition intercepts fuel vapor flowing in the inner vapor transfer passage from the canister passage to the tank passage, the fixed perforated partition being formed to include a first vent opening that leads through the first side surface to the tank - side chamber of the inner vapor transfer passage and also through the second side surface to the canister - side chamber of the inner vapor transfer passage, the fixed perforated partition further being formed to include a second vent opening that is separate from the first vent opening and leads through the first side surface to the tank - side chamber and also through the second side surface to the canister - side chamber.

[0119] Clause 2. For the tank venting system as described in Clause 1, any other suitable clause, or any combination of clauses, the fuel tank isolation valve further includes a multi-stage flow controller for keeping the first vent and the second vent formed in the fixed perforated separator normally closed to prevent fuel vapor from flowing through each of the first vent and the second vent, thereby establishing a normally closed mode of the fuel tank isolation valve such that fuel vapor cannot flow through the vapor conduit between the fuel tank and the fuel vapor recovery canister, so as to normally isolate the fuel tank from the fuel vapor recovery canister.

[0120] Clause 3. For the tank venting system as described in Clause 2, any other suitable clause, or any combination of clauses, the fuel tank isolation valve further includes means for, during an early stage of fueling the fuel tank while the pressure of the pressurized fuel vapor in the tank passage remains below a relatively high second pressure, the multi-stage flow controller is used to temporarily restrict the pressurized fuel vapor present in the tank side chamber from flowing into the canister side chamber through the first vent formed in the fixed perforated separator to initiate a partial opening of the first vent, thereby achieving a first restriction on the flow of pressurized fuel vapor through the first vent while the second vent remains closed, thereby establishing a first open mode of the fuel tank isolation valve such that the discharge flow of pressurized fuel vapor is discharged from the tank side chamber to the canister side chamber through the first vent formed in the fixed perforated separator, allowing pressurized fuel vapor to enter the canister side chamber to increase the pressure present in the canister side chamber.

[0121] Clause 4. For the tank venting system as described in Clause 3, any other suitable clause, or any combination of clauses, the fuel tank isolation valve further includes means for, during a relatively late stage of fueling the fuel tank, after the pressure of the pressurized fuel vapor present in the tank passage has risen to at least a relatively high second pressure, the multi-stage flow controller is configured to temporarily open the second vent formed in the fixed perforated baffle while restricting the flow of pressurized fuel vapor through the first vent, to achieve a different second restriction on the flow of pressurized fuel vapor through the first vent formed in the fixed perforated baffle, thereby establishing a second opening mode of the fuel tank isolation valve, such that a relatively large discharge flow of pressurized fuel vapor is discharged from the tank side chamber to the canister side chamber via the first vent and the second vent formed in the fixed perforated baffle, so that a relatively large volume of pressurized fuel vapor flowing into the tank side chamber in the tank passage can be discharged through the first vent and the second vent formed in the fixed perforated baffle, flow through the inner vapor transfer passage into the canister passage, and then flow to the fuel vapor recovery canister to dissipate the pressure in the fuel tank.

[0122] Clause 5. For the tank venting system as described in Clause 4, any other suitable clause or any combination of clauses, the fuel tank isolation valve further includes means for, during an undesired vacuum condition in the fuel tank, the multi-stage flow controller is configured to temporarily open the second vent formed in the fixed perforated baffle while the first vent is closed, in order to establish a third opening mode of the fuel tank isolation valve, to allow fuel vapor including atmospheric air to flow from the fuel vapor recovery canister to the fuel tank via the vapor conduit through the second vent formed in the fixed perforated baffle, such that the fuel vapor flowing in the canister passage enters the tank passage through the inner vapor transfer passage and then flows into the fuel tank to dissipate the undesired vacuum condition in the fuel tank.

[0123] Clause 6. For the tank ventilation system as described in Clause 5, any other suitable clause, or any combination of clauses, the fuel tank isolation valve further includes means to, during an undesired overpressure condition in the fuel tank, after the pressure of the pressurized fuel vapor present in the tank passage has risen to be higher than a relatively high second pressure to at least a third pressure, the multi-stage flow controller is used to temporarily restrict the flow of the pressurized fuel vapor present in the tank-side chamber through the first vent opening formed in the fixed perforated separator, to effect a third restriction on the flow of the pressurized fuel vapor through the first vent opening, while the second vent opening is closed, so as to establish a fourth open mode of the fuel tank isolation valve, the third restriction being different from each of the first and second restrictions on the flow of the pressurized fuel vapor through the first vent opening, such that the flow of overpressure fuel vapor through the first vent opening formed in the fixed perforated separator discharges from the tank-side chamber into the canister-side chamber, such that the overpressure fuel vapor flowing in the tank passage flows into the canister passage through the inner vapor transfer passage, and then flows to the fuel vapor recovery canister, to dissipate the undesired overpressure condition in the fuel tank.

[0124] Clause 7. For the tank ventilation system as described in Clause 6, any other suitable clause, or any combination of clauses, wherein the vapor conduit includes: a canister tube formed to include the canister passage and adapted to be coupled to the fuel vapor recovery canister at an outer end of the canister tube; a tank tube formed to include the tank passage and adapted to be coupled to the fuel tank at an outer end of the tank tube; and a valve housing formed to include the inner vapor transfer passage and coupled to inner ends of each of the canister tube and the tank tube to place the canister-side chamber of the inner vapor transfer passage in fluid communication with the canister passage and the tank-side chamber in fluid communication with the tank passage.

[0125] Clause 8. For the tank ventilation system as described in Clause 7, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller includes a tank-side vapor flow regulator mounted to move in the tank-side chamber of the inner vapor transfer passage, relative to the valve housing, toward and away from the fixed perforated separator to open and close the second vent opening formed in the fixed perforated separator.

[0126] Clause 9. The tank venting system as described in Clause 8, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller further includes a tank-side vapor flow regulator mounted to move toward and away from the tank-side vapor flow regulator relative to the valve housing in the tank-side chamber of the inner vapor transfer passage to regulate the flow of pressurized fuel vapor through the first vent formed in the fixed perforated partition.

[0127] Clause 10. The tank venting system as described in Clause 9, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller further includes a movable armature mounted to move up and down between a closed position and several open positions relative to the fixed perforated partition in an armature receiving passage formed in the tank-side vapor flow regulator. When the multi-stage flow controller is in the normally closed mode, the movable armature extends through the first vent in the closed position to engage the tank-side vapor flow regulator while the tank-side vapor flow regulator engages the second side surface of the fixed perforated partition to close the first vent. The movable armature disengages from the tank-side vapor flow regulator in the several open positions to allow the pressurized fuel vapor present in the tank-side chamber to flow through the first vent to the tank-side chamber.

[0128] Clause 11. The tank venting system as described in Clause 10, any other suitable clause, or any combination of clauses, wherein the tank-side vapor flow regulator is formed to include a vapor flow hole that communicates with the first vent when the tank-side vapor flow regulator is disposed in the tank-side chamber to engage the second side surface of the fixed perforated partition to receive the pressurized fuel vapor discharged through the first vent.

[0129] Clause 12. The tank venting system as described in Clause 11, any other suitable clause, or any combination of clauses, wherein the movable armature includes a distal tip that is disposed to engage the tank-side vapor flow regulator to close the vapor flow hole when the multi-stage flow controller is in the normally closed mode to prevent the pressurized fuel vapor present in the first vent from being discharged into the tank-side chamber.

[0130] Clause 13. The tank venting system as described in Clause 12, any other suitable clause, or any combination of clauses, wherein the distal tip of the movable armature is spaced a first distance from the vapor flow hole when the fuel tank isolation valve is in the first open mode.

[0131] Clause 14. The tank venting system as described in Clause 13, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the second open mode, the distal tip of the movable armature is spaced apart from the vapor flow hole by a second distance greater than the first distance.

[0132] Clause 15. The tank venting system as described in Clause 14, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the first open mode, the distal tip of the movable armature is arranged to extend into the first vent port.

[0133] Clause 16. The tank venting system as described in Clause 15, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the second open mode, the distal tip of the movable armature is arranged to be located outside the first vent port.

[0134] Clause 17. The tank venting system as described in Clause 14, any other suitable clause, or any combination of clauses, wherein the distal tip of the movable armature is arranged to extend into the first vent port so as to be in a first position in the first vent port when the fuel tank isolation valve is in the first open mode and in a different second position in the first vent port when the fuel tank isolation valve is in the fourth open mode.

[0135] Clause 18. The storage tank venting system as described in Clause 17, any other suitable clause, or any combination of clauses, wherein the distal tip includes a downward-facing bottom surface that faces towards the vapor flow hole formed in the tank-side vapor flow regulator.

[0136] Clause 19. The tank venting system as described in Clause 18, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the first open mode, the downward-facing bottom surface of the distal tip is arranged to be located adjacent to the first side surface of the fixed perforated partition and is spaced apart from the first side surface of the fixed perforated partition by a first distance.

[0137] Clause 20. The tank venting system as described in Clause 19, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the fourth open mode, the downward-facing bottom surface of the distal tip is arranged to be located adjacent to the second side surface of the fixed perforated partition and is spaced apart from the first side surface of the fixed perforated partition by a second distance greater than the first distance.

[0138] Clause 21. The tank venting system as described in Clause 10, any other suitable clause, or any combination of clauses, wherein the movable armature includes a distal tip which, when the movable armature is in the closed position, is arranged to engage the canister side vapor flow regulator to close the vapor flow orifice forming the canister side vapor flow regulator to communicate with the first vent and the canister side chamber.

[0139] Clause 22. The tank venting system as described in Clause 21, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the normally closed mode and the third open mode, the canister side vapor flow regulator moves to engage the second side surface of the fixed perforated baffle such that the movable armature cooperates with the canister side vapor flow regulator to close the first vent.

[0140] Clause 23. The tank venting system as described in Clause 22, any other suitable clause, or any combination of clauses, wherein the movable armature further includes a top end which is arranged to be in a spaced-apart relationship with the distal tip.

[0141] Clause 24. The tank venting system as described in Clause 23, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller further includes a compression spring having a first end engaging the top end of the movable armature and an opposite second end which normally acts against the hollow flow management unit to urge the movable armature in the inner vapor transfer passage towards the canister side vapor flow regulator such that the distal tip closes the vapor flow orifice formed in the canister side vapor flow regulator.

[0142] Clause 25. The tank venting system as described in Clause 24, any other suitable clause, or any combination of clauses, wherein the movable armature further includes an elongate body and a radially outwardly extending lifting flange, the elongate body being arranged to interconnect the top end and the distal tip, the radially outwardly extending lifting flange having an inner end coupled to the elongate body and being arranged to extend radially outwardly from a central vertical axis extending through the elongate body and the first vent.

[0143] Clause 26. A tank ventilation system as described in Clause 25, any other suitable clause, or any combination of clauses, wherein the tank-side vapor flow regulator further includes a tank-side compression spring having a first end engaging a movable tank-side closure and an opposite second end, the opposite second end of the tank-side compression spring normally acting against the hollow flow management unit to urge the movable tank-side closure to engage the first side surface of the fixed perforated partition to close the second ventilation port.

[0144] Clause 27. A tank ventilation system as described in Clause 26, any other suitable clause, or any combination of clauses, wherein the movable tank-side closure further includes: a sleeve arranged to surround a portion of the elongated body of the movable armature during movement of the movable armature relative to the valve housing; and a lift latch that is coupled to the sleeve and arranged to extend radially inwardly towards the central vertical axis to engage a radially outwardly extending lift flange of the movable armature during upward movement of the movable armature relative to the movable tank-side closure in response to energization of a solenoid included in the fuel tank isolation valve and connected to the movable armature when the fuel tank isolation valve is in the first open mode and the second open mode.

[0145] Clause 28. A tank ventilation system as described in Clause 27, any other suitable clause, or any combination of clauses, wherein the movable tank-side closure is top-hat shaped and further includes an annular base coupled to the sleeve and arranged to extend radially outwardly away from the sleeve to face towards an annular valve seat formed in the valve housing.

[0146] Clause 29. A tank ventilation system as described in Clause 28, any other suitable clause, or any combination of clauses, wherein the first end of the tank-side compression spring engages the annular base of the movable tank-side closure.

[0147] Clause 30. A tank ventilation system as described in Clause 29, any other suitable clause, or any combination of clauses, wherein a portion of the tank-side compression spring is coiled to surround the sleeve.

[0148] Clause 31. A tank ventilation system as described in Clause 22, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the first open mode, the distal tip of the movable armature is positioned at a first position among the several open positions, the tank side chamber is located outside the first vent port to position the distal tip at a first distance from the canister side vapor flow regulator to be in a spaced-apart relationship with the vapor flow orifice, and adjacent to the second side surface of the fixed perforated separator to establish the first restriction on the flow of fuel vapor through the first vent port.

[0149] Clause 32. A tank ventilation system as described in Clause 31, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the second open mode, the distal tip of the movable armature is positioned at an elevated second position among the several open positions in the tank side chamber to position the distal tip at a second distance greater than the first distance from the canister side vapor flow regulator while the canister side vapor flow regulator remains engaged with the second side surface of the fixed perforated separator so that the pressurized fuel vapor exiting the first vent port flows through the vapor flow orifice formed in the canister side vapor flow regulator to establish the second restriction on the flow of pressurized fuel vapor through the first vent port.

[0150] Clause 33. A tank ventilation system as described in Clause 22, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the normally closed mode, the tank side vapor flow regulator is arranged to engage the first side surface of the fixed perforated separator to close the second vent port formed in the fixed perforated separator, and when the fuel tank isolation valve is in the third open mode, the tank side vapor flow regulator is arranged to disengage from the first side surface of the fixed perforated separator.

[0151] Clause 34. A tank ventilation system as described in Clause 22, any other suitable clause, or any combination of clauses, wherein when the fuel tank isolation valve is in the fourth open mode, the canister side vapor flow regulator is arranged to disengage from the second side surface of the fixed perforated separator while the distal tip of the movable armature is located in the first vent port formed in the fixed perforated separator, the distal tip of the movable armature being at a third position among the several open positions to establish the third restriction on the flow of pressurized fuel vapor through the first vent port, and at the same time the tank side vapor flow regulator is arranged to engage the first side surface of the fixed perforated separator to close the second vent port formed in the fixed perforated separator.

[0152] Clause 35. A canister venting system as described in Clause 9, any other suitable clause, or any combination of clauses, wherein each of the tank-side vapor flow regulator and the canister-side vapor flow regulator is arranged to move along a single vertical axis relative to the valve housing, the fixed perforated separator, and relative to each other, the single vertical axis extending through the canister-side chamber, the first vent opening formed in the fixed perforated separator, and the tank-side chamber.

[0153] Clause 36. A canister venting system as described in Clause 35, any other suitable clause, or any combination of clauses, wherein the second vent opening includes a series of circumferentially spaced track vent openings formed in the fixed perforated separator to surround the first vent opening and the single vertical axis.

[0154] Clause 37. A canister venting system as described in Clause 35, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller further includes a movable armature mounted to move in an armature receiving channel formed in the canister-side vapor flow regulator relative to the valve housing and the canister-side vapor flow regulator and toward and away from the fixed perforated separator.

[0155] Clause 38. A canister venting system as described in Clause 37, any other suitable clause, or any combination of clauses, wherein the tank-side vapor flow regulator includes a fuel vapor flow restrictor formed to include a small-diameter vapor flow hole and a seal ring, the small-diameter vapor flow hole being relatively smaller in size than the central vent opening established by the first vent opening, the seal ring being arranged to surround the small-diameter vapor flow hole and extend toward the second side surface of the fixed perforated separator.

[0156] Clause 39. A canister venting system as described in Clause 38, any other suitable clause, or any combination of clauses, wherein when the tank-side vapor flow regulator moves in the tank-side chamber to engage the second side surface of the fixed perforated separator, the small-diameter vapor flow hole is positioned to lead to a fuel vapor vent opening channel formed in the tank-side vapor flow regulator to communicate with the tank-side chamber formed in the valve housing, and is also positioned to communicate with the central vent opening established by the first vent opening formed in the fixed perforated separator, thereby guiding pressurized fuel vapor from the canister-side chamber via the central vent opening, the small-diameter vapor flow hole, and the fuel vapor vent opening channel to the tank-side chamber.

[0157] Clause 40. The tank ventilation system as described in Clause 39, any other suitable clause, or any combination of clauses, wherein,

[0158] the movable armature includes a distal tip arranged to move between the following positions relative to the fixed perforated partition:

[0159] an extended position, extending into the central ventilation port hole formed in the fixed perforated partition, so that when the fuel tank isolation valve is in the normally closed mode, it engages the sealing ring included in the tank-side vapor flow regulator to close the small-diameter vapor flow hole formed in the fuel vapor flow restrictor, to prevent the flow of pressurized fuel vapor present in the tank-side chamber and in the central ventilation port hole formed in the fixed perforated partition through the small-diameter vapor flow hole formed in the tank-side vapor flow regulator, and when the fuel tank isolation valve is in the third open mode, to prevent the flow of gas vapor present in the tank-side chamber through the small-diameter vapor flow hole formed in the tank-side vapor flow regulator and the first ventilation port formed in the fixed perforated partition;

[0160] a retracted position, withdrawn from the central ventilation port hole formed in the fixed perforated partition, so that when the fuel tank isolation valve is in the second open mode, it allows a relatively large flow of pressurized fuel vapor discharge to flow from the tank-side chamber through the first ventilation port and the second ventilation port, and through the small-diameter vapor flow hole, and is discharged into the tank-side chamber along the fuel vapor ventilation port channel, and is transported to the fuel vapor recovery tank via the tank channel, and

[0161] an intermediate position, positioned between the extended position and the retracted position, so that when the fuel tank isolation valve is in the first open mode, the bleed flow of the pressurized fuel vapor is discharged from the tank-side chamber to the tank-side chamber via the first ventilation port.

[0162] Clause 41. The tank ventilation system according to claim 40, wherein each of the movable armature, the tank-side vapor flow regulator, and the tank-side vapor flow regulator is arranged to move relative to the valve housing, the fixed perforated partition, and relative to each other along a single vertical axis, and the single vertical axis movement extends through the tank-side chamber, the first ventilation port formed in the fixed perforated partition, the small-diameter vapor flow hole formed in the fuel vapor flow restrictor of the tank-side vapor flow regulator, and the tank-side chamber.

[0163] Clause 42. A tank venting system as described in Clause 40, any other suitable clause, or any combination of clauses, wherein during a mode change of the fuel tank isolation valve between each of the first open mode, the second open mode, the third open mode, and the fourth open mode and the normally closed mode, each of the tank side vapor flow regulator, the movable armature, and the can side vapor flow regulator is mounted in the inner vapor transfer passage formed in the valve housing for independent movement relative to each other and relative to the fixed perforated partition.

[0164] Clause 43. A tank venting system as described in Clause 8, any other suitable clause, or any combination of clauses, wherein the fixed perforated partition of the fuel tank isolation valve is coupled to the valve housing of the vapor conduit and is arranged to be entirely located within the inner vapor transfer passage formed in the valve housing.

[0165] Clause 44. A tank venting system as described in Clause 43, any other suitable clause, or any combination of clauses, wherein the first vent is established by a central vent hole formed in the fixed perforated partition, and the second vent is established by a series of track vent holes formed in the fixed perforated partition and arranged to surround the central vent hole.

[0166] Clause 45. A tank venting system as described in Clause 43, any other suitable clause, or any combination of clauses, wherein the inner diameter of the central vent hole is greater than the inner diameter of each of the track vent holes.

[0167] Clause 46. A tank venting system as described in Clause 45, any other suitable clause, or any combination of clauses, wherein the outer peripheral edge of the fixed perforated partition of the fuel tank isolation valve is coupled to the mating inner boundary wall of the valve housing to prevent movement of the fixed perforated partition relative to the valve housing of the vapor conduit.

[0168] Clause 47. A tank venting system as described in Clause 8, any other suitable clause, or any combination of clauses, wherein the boundary wall of the valve housing of the vapor conduit is arranged to surround a single vertical axis that extends through the valve housing and the first vent formed in the fixed perforated partition, the boundary wall includes a top end and an opposite bottom end, the top end of the boundary wall is formed to include a top hole that leads to the internal region defined by the boundary wall and houses the fixed perforated partition, and the opposite bottom end is arranged to be in a spaced relationship with the top end of the boundary wall and is formed to include a bottom hole that leads to the internal region.

[0169] Clause 48. A tank ventilation system as described in Clause 47, any other suitable clause, or any combination of clauses, wherein the hollow flow management unit further includes a first valve housing closure that is coupled to the top end of the boundary wall to close the top hole, and in the internal region of the valve housing between the first valve housing closure and the fixed perforated partition, a tank side chamber is established, and the tank side vapor flow regulator is positioned between the first valve housing closure and the fixed perforated partition.

[0170] Clause 49. A tank ventilation system as described in Clause 48, any other suitable clause, or any combination of clauses, wherein the tank side vapor flow regulator includes a movable tank side closure and a tank side compression spring having a first end and an opposite second end, the first end of the tank side compression spring engaging the movable tank side closure, and the opposite second end of the tank side compression spring normally acting against the first valve housing closure to urge the movable tank side closure to engage the first side surface of the fixed perforated partition, thereby closing the second vent formed in the fixed perforated partition.

[0171] Clause 50. A tank ventilation system as described in Clause 49, any other suitable clause, or any combination of clauses, wherein the movable tank side closure is top hat shaped and is formed to include an annular seal support engaging the top side of the first end of the tank side compression spring, an upright cylindrical sleeve coupled to the annular seal support, and a seal ring coupled to the lower side of the annular seal support and normally arranged to engage the first side surface of the fixed perforated partition to close the second vent.

[0172] Clause 51. A tank ventilation system as described in Clause 50, any other suitable clause, or any combination of clauses, wherein the tank side compression spring is coiled around the outer surface of the upright cylindrical sleeve of the movable tank side closure.

[0173] Clause 52. A tank ventilation system as described in Clause 51, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller further includes a tank-side vapor flow regulator and a movable armature. The tank-side vapor flow regulator is mounted to move toward and away from the tank-side vapor flow regulator in the tank-side chamber. The movable armature is mounted to move up and down between a closed position and several open positions relative to the fixed perforated partition in an armature receiving passage defined by the inner surface of the upright cylindrical sleeve of the movable tank-side closure. The movable armature extends through the first vent in the closed position to engage the tank-side vapor flow regulator, while the tank-side vapor flow regulator engages the second side surface of the fixed perforated partition to close the first vent. The movable armature disengages from the tank-side vapor flow regulator in the several open positions to allow pressurized fuel vapor present in the tank-side chamber to flow through the first vent to the tank-side chamber.

[0174] Clause 53. A tank ventilation system as described in Clause 48, any other suitable clause, or any combination of clauses, wherein the multi-stage flow controller further includes a tank-side vapor flow regulator. The tank-side vapor flow regulator is mounted to move toward and away from the tank-side vapor flow regulator in the tank-side chamber relative to the valve housing to regulate the flow of pressurized fuel vapor through the first vent formed in the fixed perforated partition. And wherein the hollow flow management unit includes a second valve housing closure that is coupled to the opposite bottom end of the boundary wall to close the bottom hole and establish the tank-side chamber in the inner region of the valve housing between the fixed perforated partition and the second valve housing closure.

[0175] Clause 54. A tank ventilation system as described in Clause 48, any other suitable clause, or any combination of clauses, wherein the tank-side vapor flow regulator includes a movable tank-side closure and a tank-side compression spring. The tank-side compression spring has a first end and an opposite second end. The first end of the tank-side compression spring engages the movable tank-side closure, and the opposite second end of the tank-side compression spring normally acts against the second valve housing closure to push the movable tank-side closure to engage the second side surface of the fixed perforated partition, thereby regulating the flow of fuel vapor through the first vent formed in the fixed perforated partition.

[0176] Clause 55. A tank venting system as described in Clause 48, any other suitable clause, or any combination of clauses, wherein the tank-side vapor flow regulator includes a fuel vapor flow restrictor formed to include a small-diameter vapor flow orifice and a tank spring. When the fuel vapor flow restrictor moves in the tank-side chamber to engage the second side surface of the fixed perforated partition, the small-diameter vapor flow orifice is aligned to communicate with the first vent port. The tank spring is positioned in the tank-side chamber and is arranged to normally act against the second valve housing closure to urge the fuel vapor flow restrictor toward the fixed perforated partition so that the annular top side of the fuel vapor flow restrictor engages the annular portion of the second side surface of the fixed perforated partition surrounding the first vent port to establish a sealed connection between the annular top side and the annular portion and block a portion of the first vent port to force any pressurized fuel vapor flowing between the tank-side chamber and the tank-side chamber to flow through the small-diameter vapor flow orifice formed in the fuel vapor flow restrictor.

[0177] Clause 56. A tank venting system comprising:

[0178] A hollow flow management unit adapted to direct fuel vapor back and forth between a fuel tank and a fuel vapor recovery canister. The hollow flow management unit includes a vapor conduit that includes a tank tube formed to include a tank passage associated with the fuel tank, a canister tube formed to include a canister passage associated with the fuel vapor recovery canister, and a valve housing formed to include an inner vapor transfer passage that fluidly interconnects the tank passage and the canister passage.

[0179] Clause 57. The tank venting system as described in Clause 56, any other suitable clause, or any combination of clauses, further comprising:

[0180] A fuel tank isolation valve positioned in the inner vapor transfer passage and configured to regulate the flow of fuel vapor in the inner vapor transfer passage between the tank passage and the canister passage.

[0181] Clause 58. The tank venting system as described in Clause 57, any other suitable clause, or any combination of clauses, wherein the fuel tank isolation valve includes a fixed perforated partition coupled to the valve housing to divide the inner vapor transfer passage, thereby establishing a tank-side chamber in communication with the tank passage on a first side of the fixed perforated partition and a canister-side chamber in communication with the canister passage on an opposite second side of the fixed perforated partition.

[0182] Clause 59. For a tank ventilation system as described in Clause 58, any other suitable clause, or any combination of clauses, the fuel tank isolation valve further includes: a tank-side vapor flow regulator mounted in the tank-side chamber to regulate the flow of fuel vapor through a second vent formed in the fixed perforated baffle, thereby fluidly interconnecting the tank-side chamber and the canister-side chamber; a spring-biased, solenoid-actuated movable armature disposed in the tank-side chamber to extend through an armature receiving passage formed in the tank-side vapor flow regulator and move relative to the tank-side vapor flow regulator and the fixed perforated baffle into a first vent that is separate from the second vent and is formed in the fixed perforated baffle; and a canister-side vapor flow regulator mounted in the canister-side chamber to cooperate with the spring-biased, solenoid-actuated movable armature to regulate the flow of fuel vapor through the first vent formed in the fixed perforated baffle.

[0183] Clause 60. For a tank ventilation system as described in Clause 59, any other suitable clause, or any combination of clauses, each of the tank-side vapor flow regulator, the canister-side vapor flow regulator, and the movable armature is arranged to move relative to the fixed perforated baffle in the inner vapor transfer passage and to move relative to each other along a single vertical axis extending through the tank-side chamber, the first vent, and the canister-side chamber.

Claims

1. A box ventilation system, comprising: A hollow flow management unit includes a vapor conduit formed to include a canister passage, a tank passage, and an inner vapor transfer passage. The canister passage is adapted to be fluidly connected to a fuel vapor recovery canister. The tank passage is adapted to be fluidly connected to a fuel tank. The inner vapor transfer passage is arranged to fluidly interconnect the canister passage and the tank passage to transfer fuel vapor flowing from the fuel tank associated with the tank passage through the tank passage and the canister passage to the fuel vapor recovery canister associated with the canister passage, and to transfer fuel vapor flowing from the fuel vapor recovery canister through the canister passage and the tank passage to the fuel tank; and a fuel tank isolation valve includes a fixed perforated partition plate installed in the inner vapor transfer passage formed in the vapor conduit to partition the inner vapor transfer passage, thereby establishing a tank-side chamber in communication with the tank passage and a canister-side chamber in communication with the canister passage, such that a first side surface of the fixed perforated partition plate intercepts fuel vapor flowing from the tank passage to the canister passage in the inner vapor transfer passage, and a second opposite side surface of the fixed perforated partition plate intercepts fuel vapor flowing from the canister passage to the tank passage in the inner vapor transfer passage. The fixed perforated partition plate is formed to include a first vent opening that leads to the tank-side chamber of the inner vapor transfer passage through the first side surface and also leads to the canister-side chamber of the inner vapor transfer passage through the second side surface. The fixed perforated partition plate is further formed to include a second vent opening that is separate from the first vent opening and leads to the tank-side chamber through the first side surface and also leads to the canister-side chamber through the second side surface, the fuel tank isolation valve further includes a multi-stage flow controller for keeping the first vent opening and the second vent opening formed in the fixed perforated partition plate normally closed to prevent fuel vapor from flowing through each of the first vent opening and the second vent opening, thereby establishing a normally closed mode of the fuel tank isolation valve such that fuel vapor cannot flow through the vapor conduit between the fuel tank and the fuel vapor recovery canister to normally isolate the fuel tank from the fuel vapor recovery canister, During the early stage of fueling the fuel tank, while the pressure of the pressurized fuel vapor in the tank passage is maintained below a relatively high second pressure, the multi-stage flow controller is used to temporarily restrict the flow of the pressurized fuel vapor present in the tank-side chamber through the first vent formed in the fixed perforated partition to initiate a partial opening of the first vent, thereby achieving a first restriction on the flow of the pressurized fuel vapor through the first vent, while the second vent remains closed, thereby establishing a first opening mode of the fuel tank isolation valve, so that the discharge flow of the pressurized fuel vapor is discharged from the tank-side chamber to the canister-side chamber through the first vent formed in the fixed perforated partition, allowing the pressurized fuel vapor to enter the canister-side chamber to increase the pressure present in the canister-side chamber. During the relatively late stage of fueling the fuel tank, after the pressure of the pressurized fuel vapor present in the tank passage has risen to at least the relatively high second pressure, the multi-stage flow controller is used to temporarily open the second vent formed in the fixed perforated partition while restricting the flow of the pressurized fuel vapor through the first vent, so as to achieve a different second restriction on the flow of the pressurized fuel vapor through the first vent formed in the fixed perforated partition, thereby establishing a second opening mode of the fuel tank isolation valve, so that a relatively large discharge flow of the pressurized fuel vapor is discharged from the tank-side chamber to the canister-side chamber through the first vent and the second vent formed in the fixed perforated partition, allowing a relatively large volume of the pressurized fuel vapor flowing into the tank-side chamber in the tank passage to be discharged through the first vent and the second vent formed in the fixed perforated partition, flow through the inner vapor transmission passage into the canister passage, and then flow to the fuel vapor recovery canister to dissipate the pressure in the fuel tank. During the period when an undesired vacuum state appears in the fuel tank, the multi-stage flow controller is used to temporarily open the second vent formed in the fixed perforated partition while the first vent is closed, so as to establish a third opening mode of the fuel tank isolation valve, allowing the fuel vapor including atmospheric air to flow from the fuel vapor recovery canister to the fuel tank through the second vent formed in the fixed perforated partition via the vapor conduit, so that the fuel vapor flowing in the canister passage enters the tank passage through the inner vapor transmission passage and then flows into the fuel tank to dissipate the undesired vacuum state in the fuel tank. During a period in which an undesired overpressure condition occurs in the fuel tank, after the pressure of the pressurized fuel vapor present in the tank passage has risen to at least a third pressure, which is higher than a relatively high second pressure, the multi-stage flow controller is operative to temporarily restrict the flow of the pressurized fuel vapor present in the tank-side chamber through the first vent opening formed in the fixed perforated separator to effect a third restriction on the flow of the pressurized fuel vapor through the first vent opening, while the second vent opening is closed so as to establish a fourth open mode of the fuel tank isolation valve, the third restriction being different from each of a first restriction and a second restriction on the flow of the pressurized fuel vapor through the first vent opening, such that the flow of overpressure fuel vapor through the first vent opening formed in the fixed perforated separator discharges from the tank-side chamber into the canister-side chamber, such that the overpressure fuel vapor flowing in the tank passage flows through the inner vapor transfer passage into the canister passage and then to the fuel vapor recovery canister to dissipate the undesired overpressure condition in the fuel tank.

2. The box ventilation system according to claim 1, wherein, The vapor conduit includes: a canister tube formed to include the canister passage and adapted to be coupled to the fuel vapor recovery canister at an outer end of the canister tube; a tank tube formed to include the tank passage and adapted to be coupled to the fuel tank at an outer end of the tank tube; and a valve housing formed to include the inner vapor transfer passage and coupled to inner ends of each of the canister tube and the tank tube to place the canister-side chamber of the inner vapor transfer passage in fluid communication with the canister passage and the tank-side chamber in fluid communication with the tank passage, and wherein the multi-stage flow controller includes a tank-side vapor flow regulator mounted to move in the tank-side chamber of the inner vapor transfer passage relative to the valve housing toward and away from the fixed perforated separator to open and close the second vent opening formed in the fixed perforated separator.

3. The box ventilation system according to claim 2, wherein, The multi-stage flow controller further includes a canister-side vapor flow regulator mounted to move in the canister-side chamber of the inner vapor transfer passage relative to the valve housing toward and away from the tank-side vapor flow regulator to regulate the flow of the pressurized fuel vapor through the first vent opening formed in the fixed perforated separator.

4. The box ventilation system according to claim 3, wherein, The multi-stage flow controller further includes a movable armature mounted to move vertically between a closed position and several open positions relative to the fixed perforated partition in an armature receiving passage formed in the tank side vapor flow regulator. When the multi-stage flow controller is in the normally closed mode, the movable armature extends through the first vent opening in the closed position to engage the tank side vapor flow regulator, while the tank side vapor flow regulator engages the second side surface of the fixed perforated partition to close the first vent opening. The movable armature is disengaged from the tank side vapor flow regulator in the several open positions to allow pressurized fuel vapor present in the tank side chamber to flow through the first vent opening to the tank side chamber.

5. The box ventilation system according to claim 4, wherein, The tank side vapor flow regulator is formed to include a vapor flow hole. When the tank side vapor flow regulator is disposed in the tank side chamber to engage the second side surface of the fixed perforated partition, the vapor flow hole communicates with the first vent opening to accommodate pressurized fuel vapor discharged through the first vent opening. And the movable armature includes a distal tip. When the multi-stage flow controller is in the normally closed mode, the distal tip is disposed to engage the tank side vapor flow regulator to close the vapor flow hole to prevent pressurized fuel vapor present in the first vent opening from being discharged into the tank side chamber. And when the fuel tank isolation valve is in the first open mode, the distal tip is spaced from the vapor flow hole by a first distance, and when the fuel tank isolation valve is in the second open mode, the distal tip is spaced from the vapor flow hole by a second distance greater than the first distance.

6. The box ventilation system according to claim 5, wherein, When the fuel tank isolation valve is in the first open mode, the distal tip of the movable armature is disposed to extend into the first vent opening, and when the fuel tank isolation valve is in the second open mode, the distal tip of the movable armature is disposed outside the first vent opening.

7. The box ventilation system according to claim 5, wherein, The distal tip of the movable armature is disposed to extend into the first vent opening such that it is in a first position in the first vent opening when the fuel tank isolation valve is in the first open mode and in a different second position in the first vent opening when the fuel tank isolation valve is in the fourth open mode.

8. The box ventilation system according to claim 7, wherein, The distal tip includes a downward-facing bottom surface that faces the vapor flow hole formed in the can-side vapor flow regulator, and when the fuel tank isolation valve is in the first open mode, the downward-facing bottom surface of the distal tip is arranged to be located adjacent to the first side surface of the fixed perforated partition and at a first distance from the first side surface of the fixed perforated partition, and when the fuel tank isolation valve is in the fourth open mode, the downward-facing bottom surface of the distal tip is arranged to be located adjacent to the second side surface of the fixed perforated partition and at a second distance greater than the first distance from the first side surface of the fixed perforated partition.

9. The box ventilation system according to claim 4, wherein, The movable armature includes a distal tip that, when the movable armature is in the closed position, is arranged to engage the can-side vapor flow regulator to close the vapor flow hole forming the can-side vapor flow regulator to communicate with the first vent port and the can-side chamber, and when the fuel tank isolation valve is in the normally closed mode and the third open mode, the can-side vapor flow regulator moves to engage the second side surface of the fixed perforated partition so that the movable armature cooperates with the can-side vapor flow regulator to close the first vent port.

10. The box ventilation system according to claim 9, wherein, The movable armature further includes a top end, the top end of the movable armature is arranged to be in a spaced relationship with the distal tip, and the multi-stage flow controller further includes a compression spring having a first end that engages the top end of the movable armature and an opposite second end, the opposite second end of the compression spring generally acts against the hollow flow management unit to push the movable armature in the inner vapor transmission channel toward the can-side vapor flow regulator so that the distal tip closes the vapor flow hole formed in the can-side vapor flow regulator.

11. The box ventilation system according to claim 10, wherein, The movable armature further includes an elongate body and a radially outwardly extending lifting flange, the elongate body being arranged to interconnect the top end and the distal tip, the radially outwardly extending lifting flange having an inner end coupled to the elongate body and being arranged to extend radially outwardly from a central vertical axis extending through the elongate body and the first vent port. The tank-side vapor flow regulator further includes a tank-side compression spring having a first end engaging the movable tank-side closure and an opposite second end, the opposite second end of the tank-side compression spring normally acting against the hollow flow management unit to urge the movable tank-side closure to engage the first side surface of the fixed perforated baffle, thereby closing the second vent port. The movable tank-side closure further includes: a sleeve arranged to surround a portion of the elongate body of the movable armature during movement of the movable armature relative to the valve housing; and a lifting latch coupled to the sleeve and arranged to extend radially inwardly toward the central vertical axis to engage the radially outwardly extending lifting flange of the movable armature during upward movement of the movable armature relative to the movable tank-side closure in response to energization of a solenoid included in the fuel tank isolation valve and connected to the movable armature when the fuel tank isolation valve is in the first open mode and the second open mode.

12. The box ventilation system according to claim 11, wherein, The movable tank-side closure is top-hat shaped and further includes an annular base coupled to the sleeve and arranged to extend radially outwardly away from the sleeve to face toward an annular valve seat formed in the valve housing. The first end of the tank-side compression spring engages the annular base of the movable tank-side closure, and a portion of the tank-side compression spring is coiled to surround the sleeve.

13. The box ventilation system according to claim 9, wherein, When the fuel tank isolation valve is in the first open mode, the distal tip of the movable armature is positioned at a first position among the several open positions, the tank-side chamber being located outside the first vent port to position the distal tip at a first distance from the tank-side vapor flow regulator, to be in a spaced relationship with the vapor flow orifice, and adjacent to the second side surface of the fixed perforated baffle to establish the first restriction to the flow of fuel vapor through the first vent port.

14. The box ventilation system according to claim 13, wherein, When the fuel tank isolation valve is in the second open mode, the distal tip of the movable armature is positioned at an elevated second position among the several open positions in the tank-side chamber to position the distal tip at a second distance greater than the first distance from the tank-side vapor flow regulator, while the tank-side vapor flow regulator remains engaged with the second side surface of the fixed perforated baffle such that pressurized fuel vapor exiting the first vent flows through the vapor flow holes formed in the tank-side vapor flow regulator to establish the second restriction to the flow of pressurized fuel vapor through the first vent.

15. The box ventilation system according to claim 9, wherein, When the fuel tank isolation valve is in the normally closed mode, the tank-side vapor flow regulator is arranged to engage the first side surface of the fixed perforated baffle to close the second vent formed in the fixed perforated baffle, and when the fuel tank isolation valve is in the third open mode, the tank-side vapor flow regulator is arranged to disengage from the first side surface of the fixed perforated baffle.

16. The box ventilation system according to claim 9, wherein, When the fuel tank isolation valve is in the fourth open mode, the tank-side vapor flow regulator is arranged to disengage from the second side surface of the fixed perforated baffle while the distal tip of the movable armature is located in the first vent formed in the fixed perforated baffle, and the distal tip of the movable armature is in a third position among the several open positions to establish the third restriction to the flow of pressurized fuel vapor through the first vent, and at the same time the tank-side vapor flow regulator is arranged to engage the first side surface of the fixed perforated baffle to close the second vent formed in the fixed perforated baffle.

17. The box ventilation system according to claim 3, wherein, Each of the tank-side vapor flow regulator and the tank-side vapor flow regulator is arranged to move along a single vertical axis relative to the valve housing, the fixed perforated baffle, and relative to each other, and the single vertical axis extends through the tank-side chamber, the first vent formed in the fixed perforated baffle, and the tank-side chamber.

18. The cassette ventilation system according to claim 17, wherein, The second vent includes a series of circumferentially spaced track vent holes formed in the fixed perforated baffle to surround the first vent and the single vertical axis.

19. The cassette ventilation system according to claim 17, wherein, The multi-stage flow controller further includes a movable armature mounted to move within an armature receiving passage formed in the tank-side vapor flow regulator, relative to the valve housing and the tank-side vapor flow regulator and toward and away from the fixed perforated baffle. The canister-side vapor flow regulator includes a fuel vapor flow restrictor formed to include a vapor flow orifice and a seal ring. The vapor flow orifice is relatively smaller in size than the central vent orifice established by the first vent. The seal ring is arranged to surround the vapor flow orifice and extend toward the second side surface of the fixed perforated baffle. When the canister-side vapor flow regulator moves within the canister-side chamber to engage the second side surface of the fixed perforated baffle, the vapor flow orifice is positioned to lead to a fuel vapor vent passage formed in the canister-side vapor flow regulator to communicate with the canister-side chamber formed in the valve housing, and is also positioned to communicate with the central vent orifice established by the first vent formed in the fixed perforated baffle, thereby guiding pressurized fuel vapor from the tank-side chamber through the central vent orifice, the vapor flow orifice, and the fuel vapor vent passage to the canister-side chamber, and wherein the movable armature includes a distal tip arranged to move between the following positions relative to the fixed perforated baffle: An extended position, extending into the central vent orifice formed in the fixed perforated baffle, so that when the fuel tank isolation valve is in the normally closed mode, it engages the seal ring included in the canister-side vapor flow regulator to close the vapor flow orifice formed in the fuel vapor flow restrictor, to prevent the flow of pressurized fuel vapor present in the tank-side chamber and in the central vent orifice formed in the fixed perforated baffle through the vapor flow orifice formed in the canister-side vapor flow regulator, and to prevent the flow of fuel gas vapor present in the canister-side chamber through the vapor flow orifice formed in the canister-side vapor flow regulator and the first vent formed in the fixed perforated baffle when the fuel tank isolation valve is in the third open mode; A retracted position, withdrawn from the central vent orifice formed in the fixed perforated baffle, so that when the fuel tank isolation valve is in the second open mode, it allows a relatively large discharge flow of pressurized fuel vapor to pass from the tank-side chamber through the first vent and the second vent, and through the vapor flow orifice, and flow along the fuel vapor vent passage into the canister-side chamber and be transported to the fuel vapor recovery canister via the canister passage, and An intermediate position, positioned between the extended position and the retracted position, so that when the fuel tank isolation valve is in the first open mode, the bleed flow of the pressurized fuel vapor is discharged from the tank-side chamber through the first vent into the canister-side chamber.

20. The cassette ventilation system according to claim 19, wherein, Each of the movable armature, the tank-side vapor flow regulator, and the canister-side vapor flow regulator is arranged to move relative to the valve housing, the fixed perforated partition, and relative to each other along a single vertical axis that extends through the canister-side chamber, the first vent opening formed in the fixed perforated partition, the vapor flow orifice formed in the fuel vapor flow restrictor of the tank-side vapor flow regulator, and the tank-side chamber.

21. The cassette ventilation system according to claim 19, wherein, During a mode change of the fuel tank isolation valve between each of the first open mode, the second open mode, the third open mode, and the fourth open mode and the normally closed mode, each of the canister-side vapor flow regulator, the movable armature, and the tank-side vapor flow regulator is mounted in the inner vapor transfer passage formed in the valve housing for independent movement relative to each other and relative to the fixed perforated partition.

22. The cassette ventilation system according to claim 2, wherein, The fixed perforated partition of the fuel tank isolation valve is coupled to the valve housing of the vapor conduit and is arranged to be entirely located within the inner vapor transfer passage formed in the valve housing.

23. The cassette ventilation system according to claim 22, wherein, The first vent opening is established by a central vent opening hole formed in the fixed perforated partition, and the second vent opening is established by a series of track vent opening holes formed in the fixed perforated partition and arranged to surround the central vent opening hole.

24. The cassette ventilation system according to claim 23, wherein, The inner diameter of the central vent opening hole is larger than the inner diameter of each of the track vent opening holes.

25. The cassette ventilation system according to claim 24, wherein, The outer peripheral edge of the fixed perforated partition of the fuel tank isolation valve is coupled to the mating inner boundary wall of the valve housing to prevent movement of the fixed perforated partition relative to the valve housing of the vapor conduit.

26. The cassette ventilation system according to claim 2, wherein, The boundary wall of the valve housing of the vapor conduit is arranged to surround a single vertical axis that extends through the valve housing and the first vent opening formed in the fixed perforated partition. The boundary wall includes a top end and an opposite bottom end. The top end of the boundary wall is formed to include a top hole that leads to the internal region defined by the boundary wall and houses the fixed perforated partition. The opposite bottom end is arranged to be in a spaced-apart relationship with the top end of the boundary wall and is formed to include a bottom hole that leads to the internal region. And wherein, the hollow flow management unit further includes a first valve housing closure that is coupled to the top end of the boundary wall to close the top hole, and in the internal region of the valve housing between the first valve housing closure and the fixed perforated partition, the canister-side chamber is established and the canister-side vapor flow regulator is positioned between the first valve housing closure and the fixed perforated partition.

27. The cassette ventilation system according to claim 26, wherein, The tank side vapor flow regulator includes a movable tank side closure and a tank side compression spring having a first end and an opposite second end. The first end of the tank side compression spring engages the movable tank side closure, and the opposite second end of the tank side compression spring normally acts against the first valve housing closure to urge the movable tank side closure to engage the first side surface of the fixed perforated baffle, thereby closing the second vent formed in the fixed perforated baffle.

28. The cassette ventilation system according to claim 27, wherein, The movable tank side closure is in the shape of a top hat and is formed to include an annular seal support engaging the top side of the first end of the tank side compression spring, a vertical cylindrical sleeve coupled to the annular seal support, and a seal ring coupled to the lower side of the annular seal support and normally arranged to engage the first side surface of the fixed perforated baffle to close the second vent.

29. The cassette ventilation system according to claim 28, wherein, The tank side compression spring is coiled to surround the outer surface of the vertical cylindrical sleeve of the movable tank side closure.

30. The cassette ventilation system according to claim 29, wherein, The multi-stage flow controller further includes a canister side vapor flow regulator and a movable armature. The canister side vapor flow regulator is mounted to move in the canister side chamber toward and away from the tank side vapor flow regulator. The movable armature is mounted to move up and down between a closed position and several open positions relative to the fixed perforated baffle in an armature receiving passage defined by the inner surface of the vertical cylindrical sleeve of the movable tank side closure. The movable armature extends through the first vent in the closed position to engage the canister side vapor flow regulator while the canister side vapor flow regulator engages the second side surface of the fixed perforated baffle to close the first vent. The movable armature disengages from the canister side vapor flow regulator in the several open positions to allow pressurized fuel vapor present in the tank side chamber to flow through the first vent to the canister side chamber.

31. The cassette ventilation system according to claim 26, wherein, The multi-stage flow controller further includes a canister side vapor flow regulator mounted to move in the canister side chamber relative to the valve housing toward and away from the tank side vapor flow regulator to regulate the flow of pressurized fuel vapor through the first vent formed in the fixed perforated baffle. And wherein, the hollow flow management unit includes a second valve housing closure coupled to the opposite bottom end of the boundary wall to close the bottom hole and establish the canister side chamber in the inner region of the valve housing between the fixed perforated baffle and the second valve housing closure.

32. The cassette ventilation system according to claim 31, wherein, The tank-side vapor flow regulator includes a movable tank-side closure and a tank-side compression spring having a first end and an opposite second end, the first end of the tank-side compression spring engaging the movable tank-side closure, and the opposite second end of the tank-side compression spring normally acting against the second valve housing closure to urge the movable tank-side closure to engage the second side surface of the fixed perforated separator, thereby regulating the flow of fuel vapor through the first vent formed in the fixed perforated separator.

33. The cassette ventilation system according to claim 31, wherein, The tank-side vapor flow regulator includes a fuel vapor flow restrictor formed to include a vapor flow hole and a tank spring. When the fuel vapor flow restrictor moves in the tank-side chamber to engage the second side surface of the fixed perforated separator, the vapor flow hole is aligned to communicate with the first vent. The tank spring is positioned in the tank-side chamber and arranged to normally act against the second valve housing closure to urge the fuel vapor flow restrictor toward the fixed perforated separator so that the annular top side of the fuel vapor flow restrictor engages the annular portion of the second side surface of the fixed perforated separator surrounding the first vent to establish a sealed connection between the annular top side and the annular portion and block a portion of the first vent to force any pressurized fuel vapor flowing between the tank-side chamber and the tank-side chamber to flow through the vapor flow hole formed in the fuel vapor flow restrictor.

34. A cassette ventilation system, comprising: A hollow flow management unit adapted to direct fuel vapor back and forth between a fuel tank and a fuel vapor recovery canister, the hollow flow management unit including a vapor conduit including a tank tube formed to include a tank passage associated with the fuel tank, a canister tube formed to include a canister passage associated with the fuel vapor recovery canister, and a valve housing formed to include an inner vapor transfer passage fluidly interconnecting the tank passage and the canister passage; and A fuel tank isolation valve, positioned in the inner vapor transfer passage and configured to regulate the flow of fuel vapor in the inner vapor transfer passage between the tank passage and the canister passage. The fuel tank isolation valve includes a fixed perforated separator plate that is coupled to the valve housing to divide the inner vapor transfer passage, thereby establishing a tank-side chamber in communication with the tank passage on a first side of the fixed perforated separator plate and a canister-side chamber in communication with the canister passage on an opposite second side of the fixed perforated separator plate. The fuel tank isolation valve further includes: a tank-side vapor flow regulator mounted in the tank-side chamber to regulate the flow of fuel vapor through a second vent formed in the fixed perforated separator plate, thereby fluidly interconnecting the tank-side chamber and the canister-side chamber; a spring-biased solenoid-actuated movable armature disposed in the tank-side chamber to extend through an armature receiving passage formed in the tank-side vapor flow regulator and move relative to the tank-side vapor flow regulator and the fixed perforated separator plate into a first vent that is separate from the second vent and formed in the fixed perforated separator plate; and a canister-side vapor flow regulator mounted in the canister-side chamber to cooperate with the spring-biased solenoid-actuated movable armature to regulate the flow of fuel vapor through the first vent formed in the fixed perforated separator plate.

35. The cassette ventilation system according to claim 34, wherein,Each of the tank-side vapor flow regulator, the canister-side vapor flow regulator, and the movable armature is arranged to move relative to the fixed perforated separator plate in the inner vapor transfer passage and to move relative to one another along a single vertical axis extending through the tank-side chamber, the first vent, and the canister-side chamber.

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