WO2022043922A1 - Improved fuel tank isolation valve to reduce solenoid size - Google Patents

Improved fuel tank isolation valve to reduce solenoid size Download PDF

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Publication number
WO2022043922A1
WO2022043922A1 PCT/IB2021/057843 IB2021057843W WO2022043922A1 WO 2022043922 A1 WO2022043922 A1 WO 2022043922A1 IB 2021057843 W IB2021057843 W IB 2021057843W WO 2022043922 A1 WO2022043922 A1 WO 2022043922A1
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WO
WIPO (PCT)
Prior art keywords
function
fuel tank
valve
isolation valve
improved fuel
Prior art date
Application number
PCT/IB2021/057843
Other languages
French (fr)
Inventor
Kabir BHANDARI
Amardip KUMAR
Varun Kumar
Sahil Singla
Original Assignee
Padmini Vna Mechatronics Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Padmini Vna Mechatronics Ltd. filed Critical Padmini Vna Mechatronics Ltd.
Publication of WO2022043922A1 publication Critical patent/WO2022043922A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K15/035—Fuel tanks characterised by venting means
    • B60K15/03519—Valve arrangements in the vent line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
    • F16K17/02—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side
    • F16K17/04—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side spring-loaded
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
    • F16K17/02—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side
    • F16K17/04—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side spring-loaded
    • F16K17/048—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side spring-loaded combined with other safety valves, or with pressure control devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
    • F16K17/02—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side
    • F16K17/04—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side spring-loaded
    • F16K17/06—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side spring-loaded with special arrangements for adjusting the opening pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
    • F16K17/18—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on either side
    • F16K17/19—Equalising valves predominantly for tanks
    • F16K17/196—Equalising valves predominantly for tanks spring-loaded
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K31/00—Actuating devices; Operating means; Releasing devices
    • F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
    • F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
    • F16K31/0644—One-way valve
    • F16K31/0655—Lift valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K2015/03256—Fuel tanks characterised by special valves, the mounting thereof
    • B60K2015/03296—Pressure regulating valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K15/035—Fuel tanks characterised by venting means
    • B60K2015/03561—Venting means working at specific times
    • B60K2015/03576—Venting during filling the reservoir

Definitions

  • the present invention relates to an improved fuel tank isolation valve for maintaining the fuel tank pressure within the protected pressure range and over pressure relief and over vacuum relief function is provided in a separate chamber for reduction in sealing diameter for over vacuum relief function which consequently reduces the solenoid force requirement and size of solenoid i.e. a smaller solenoid is used to operate the valve thereby reducing the weight of the valve.
  • the fuel tanks are closed and pressurized systems, thus in general due to evaporation of stored fuel a positive pressure inside the fuel tank is developed. Moreover, it is necessary for vehicles to maintain an elevated pressure in the fuel tank to suppress the rate of fuel vapor generation and to minimize hydrocarbon emissions to the atmosphere.
  • the most obvious solution, to maintain the pressure inside the tank in a pressure protected range is to install a fuel tank isolation valve (FTIV) coupled to fuel tank to control fuel tank venting.
  • the fuel tank isolation valve (FTIV) may be located in a conduit between a fuel tank and a fuel vapor canister in an evaporative emission control system. It opens automatically when the pressure exceeds protection limits and is electrically actuated at the time of refueling.
  • the fuel tank isolation valve enables fuel vapor containment in the fuel tank until conditions are appropriate for the engine to process the excess vapor.
  • flow happens from fuel tank side to canister side of the vehicle whereas on over vacuum condition flow happens from canister side of the vehicle to tank side of the vehicle.
  • refueling flow happens from tank side to canister side of the vehicle.
  • FTIV fuel tank isolation valve
  • valves need to do the electrical opening of the valve (with energization) at the time of refueling the vehicle.
  • One port of the valve is connected to fuel tank of the vehicle and whereas other port of the valve is connected to canister of the vehicle.
  • a fuel tank isolation valve in which over pressure relief and over vacuum relief functions are provided on the same axis and in one above the other manner, a larger sealing diameter is required. Due to large sealing diameter, the size of valve is also large. Also, the solenoid force requirement is more which consequently requires bigger solenoid and it increases the weight of the valve and the end product in which it is used.
  • the main object of the present invention is to provide an improved fuel tank isolation valve that requires reduced sealing diameter and a smaller solenoid which shall reduce the solenoid force requirement and weight of the valve.
  • Another object of the present invention is to provide an improved fuel tank isolation valve for maintaining the fuel tank pressure within the protected pressure range and provide over pressure relief and over vacuum relief function in a separate chamber that reduce the sealing diameter and the ultimate size of valve and reduces overall weight of the valve as well.
  • Still another object of the present invention is to provide an improved fuel tank isolation valve with precise control of sealing points using an adjustment screw.
  • the present invention provides an improved fuel tank isolation valve (FTIV) that maintains the pressure inside the fuel tank in a protected pressure range either in over pressure or in under pressure condition, that requires current only during switching ON and OFF the valve.
  • FTIV fuel tank isolation valve
  • An over pressure relief and an over vacuum relief functions are provided in a separate chamber so sealing diameter for the over vacuum relief function is reduced.
  • an improved fuel tank isolation valve comprises of a valve housing and a solenoid housing.
  • the valve housing has a canister port, a tank port, a chamber for an over pressure relief function including a first compression spring for the over pressure relief function and an adjusting screw with which a spring load is adjusted more precisely, a primary seal sub assembly for the over pressure relief function and a primary sealing surface.
  • the over pressure relief function is provided in a separate chamber so sealing diameter for an over vacuum relief function is reduced and hence the solenoid spring force requirement is also reduced.
  • a secondary seal sub assembly and a secondary sealing surface is provided in an another chamber of the valve housing.
  • the solenoid housing comprises an electrical terminal, a second compression spring for the over vacuum relief function, a solenoid and a shaft. Therefore, a smaller solenoid is used to operate the valve. This reduces the overall weight of the valve and end product.
  • the adjustment screw is provided for adjusting the spring load precisely.
  • the present invention provides an improved fuel tank isolation valve with a smaller solenoid required to operate the valve which reduces the ultimate size of valve and overall weight of the valve as well.
  • Fig. 1 is a sectional view of the fuel tank isolation valve showing the housing in accordance with the present invention.
  • Fig. 2(a) and Fig. 2(b) is a sectional view of the fuel tank isolation valve in idle condition in accordance with the present invention.
  • Figs. 3(a) and 3(b) is a sectional view of the fuel tank isolation valve in ON condition in accordance with the present invention.
  • Figs. 4(a) and 4(b) is a sectional view of the fuel tank isolation valve working in OPR condition in accordance with the present invention.
  • Figs. 5(a) and 5(b) is a sectional view of the fuel tank isolation valve working in OVR condition in accordance with the present invention.
  • the present invention provides an over pressure relief (OPR) and an over vacuum relief (OVR) functions separately so that both functions are controlled independently and also provides a screw adjustment for the OPR function to control the sealing points.
  • OPR over pressure relief
  • OVR over vacuum relief
  • an improved fuel tank isolation valve comprises of a valve housing and a solenoid housing.
  • the valve housing has a canister port, a tank port, a chamber for an over pressure relief function including a first compression spring for the over pressure relief function and an adjusting screw with which a spring load is adjusted more precisely, a primary seal sub assembly for the over pressure relief function and a primary sealing surface.
  • the over pressure relief function is provided in a separate chamber so sealing diameter for an over vacuum relief function is reduced and hence the solenoid spring force requirement is also reduced.
  • a secondary seal sub assembly and a secondary sealing surface is provided in an another chamber of the valve housing.
  • the solenoid housing comprises an electrical terminal, a second compression spring for the over vacuum relief function, a solenoid and a shaft. Therefore, a smaller solenoid is used to operate the valve. This reduces the overall weight of the valve and end product.
  • the adjustment screw is provided for adjusting the spring load precisely.
  • FIG. 1 a sectional view of the fuel tank isolation valve showing the housing of the fuel tank isolation valve (100) in accordance with the present invention is shown.
  • the improved fuel tank isolation valve (100) comprises a tank port (9) and a canister port (10).
  • a chamber (14) for OPR function includes a first compression spring (4) for OPR function and an adjusting screw (7) with which spring load is adjusted more precisely, a primary seal sub assembly (5) for OPR function and a primary sealing surface (6).
  • a second compression spring (1) for OVR function holds a secondary seal sub assembly (2) for OVR function in contact with secondary sealing surface (3) and keep the valve closed and the first compression spring (4) keeps the primary seal sub assembly (5) for OPR function in contact with the primary sealing surface (6).
  • the adjustment screw (7) is provided in chamber used for OPR function to precisely adjust the spring load.
  • Electrical terminal (11) is provided for electrical input to the valve for operation.
  • a sectional view of the fuel tank isolation valve in idle condition in accordance with the present invention is shown respectively.
  • a second compression spring (1) used for OVR function holds the secondary seal sub assembly (2) for OVR function in contact with the secondary sealing surface (3) and keep the valve closed and the first compression spring (4) keeps the primary seal sub assembly (5) for OPR function in contact with the primary sealing surface (6).
  • both the openings are closed and the tank port (9) is not connected to the canister port (10) of the valve till the pressure inside the tank is within the safety limit and the fuel vapours remain inside the fuel tank.
  • a sectional view of the fuel tank isolation valve in ON condition in accordance with the present invention is shown.
  • solenoid of the valve will be turned ON and the moving core (12) of the solenoid moves downwards causing the secondary seal sub assembly (2) for OPR function to detach from the secondary sealing surface (3).
  • the port gets opened and connects the tank port (9) to the canister port (10) at the time of actuation during refueling.
  • sectional view of the fuel tank isolation valve working in OPR condition in accordance with the present invention is shown. As shown in Fig.
  • FIG. 5(a) and 5(b) sectional view of the fuel tank isolation valve working in OVR condition in accordance with the present invention is shown.
  • vacuum gets built inside the chamber (13) and the compression spring (1) for OVR function keeps the seal sub assembly (2) for OVR function in contact with the sealing surface (3) of canister port (10) keeping the valve in closed condition.
  • Fig. 5(b) when the vacuum increases beyond the protection point limit, the force by vacuum compresses the compression spring (1) and the seal sub assembly (2) for OVR function moves downwards. Due to the movement of the seal sub assembly (2), the port gets opened and flow takes place from the canister port (10) to the tank port (9). During opening, the vacuum gets released from the tank and again when the vacuum level reaches to a safety limit, the port closes.
  • the present invention provides an improved fuel tank isolation valve with over pressure relief function provided in a separate chamber that has no impact on the spring load of OVR function and hence, the required solenoid spring force reduces and a smaller solenoid is required to operate the valve.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)
  • Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)

Abstract

The present invention relates to an improved fuel tank isolation valve (100) for maintaining the fuel tank pressure within the protected pressure range. The improved fuel tank isolation valve (100) comprises a solenoid housing and a valve housing. The valve housing comprising a tank port (9), a canister port (10), an adjusting screw (7) and a separate chamber. An over pressure relief and an over vacuum relief function is provided in a separate chamber. The separate chamber is for reduction in sealing diameter for over vacuum relief function which consequently reduces the solenoid force requirement and size of solenoid. With the disclosed invention, a smaller solenoid is used for operating the valve thereby reducing the weight of the valve.

Description

“IMPROVED FUEL TANK ISOLATION VALVE TO REDUCE SOLENOID SIZE”
FIELD OF THE INVENTION
The present invention relates to an improved fuel tank isolation valve for maintaining the fuel tank pressure within the protected pressure range and over pressure relief and over vacuum relief function is provided in a separate chamber for reduction in sealing diameter for over vacuum relief function which consequently reduces the solenoid force requirement and size of solenoid i.e. a smaller solenoid is used to operate the valve thereby reducing the weight of the valve.
BACKGROUND OF THE INVENTION
In vehicles, the fuel tanks are closed and pressurized systems, thus in general due to evaporation of stored fuel a positive pressure inside the fuel tank is developed. Moreover, it is necessary for vehicles to maintain an elevated pressure in the fuel tank to suppress the rate of fuel vapor generation and to minimize hydrocarbon emissions to the atmosphere. The most obvious solution, to maintain the pressure inside the tank in a pressure protected range is to install a fuel tank isolation valve (FTIV) coupled to fuel tank to control fuel tank venting. The fuel tank isolation valve (FTIV) may be located in a conduit between a fuel tank and a fuel vapor canister in an evaporative emission control system. It opens automatically when the pressure exceeds protection limits and is electrically actuated at the time of refueling.
The fuel tank isolation valve (FTIV) enables fuel vapor containment in the fuel tank until conditions are appropriate for the engine to process the excess vapor. At the time of over pressure condition inside the fuel tank, flow happens from fuel tank side to canister side of the vehicle whereas on over vacuum condition flow happens from canister side of the vehicle to tank side of the vehicle. At the time of refueling flow happens from tank side to canister side of the vehicle.
In case there is a negative pressure or vacuum generated due to falling temperatures (e.g. if a car is parked overnight), fuel tank isolation valve (FTIV) open automatically and allows vacuum seal to open and connect the fuel tank with canister to maintain the vehicle tank pressure in a protected range.
Additionally, valves need to do the electrical opening of the valve (with energization) at the time of refueling the vehicle. One port of the valve is connected to fuel tank of the vehicle and whereas other port of the valve is connected to canister of the vehicle.
A fuel tank isolation valve in which over pressure relief and over vacuum relief functions are provided on the same axis and in one above the other manner, a larger sealing diameter is required. Due to large sealing diameter, the size of valve is also large. Also, the solenoid force requirement is more which consequently requires bigger solenoid and it increases the weight of the valve and the end product in which it is used.
Therefore, there is a need of a technology in isolation valves to reduce the sealing diameter which shall reduce the valve size and solenoid force requirement.
OBJECT OF THE INVENTION
The main object of the present invention is to provide an improved fuel tank isolation valve that requires reduced sealing diameter and a smaller solenoid which shall reduce the solenoid force requirement and weight of the valve.
Another object of the present invention is to provide an improved fuel tank isolation valve for maintaining the fuel tank pressure within the protected pressure range and provide over pressure relief and over vacuum relief function in a separate chamber that reduce the sealing diameter and the ultimate size of valve and reduces overall weight of the valve as well.
Still another object of the present invention is to provide an improved fuel tank isolation valve with precise control of sealing points using an adjustment screw.
SUMMARY OF THE INVENTION
The present invention provides an improved fuel tank isolation valve (FTIV) that maintains the pressure inside the fuel tank in a protected pressure range either in over pressure or in under pressure condition, that requires current only during switching ON and OFF the valve. An over pressure relief and an over vacuum relief functions are provided in a separate chamber so sealing diameter for the over vacuum relief function is reduced.
In an embodiment of the present invention, an improved fuel tank isolation valve (FTIV) comprises of a valve housing and a solenoid housing. The valve housing has a canister port, a tank port, a chamber for an over pressure relief function including a first compression spring for the over pressure relief function and an adjusting screw with which a spring load is adjusted more precisely, a primary seal sub assembly for the over pressure relief function and a primary sealing surface. The over pressure relief function is provided in a separate chamber so sealing diameter for an over vacuum relief function is reduced and hence the solenoid spring force requirement is also reduced. For the over vacuum relief, a secondary seal sub assembly and a secondary sealing surface is provided in an another chamber of the valve housing. The solenoid housing comprises an electrical terminal, a second compression spring for the over vacuum relief function, a solenoid and a shaft. Therefore, a smaller solenoid is used to operate the valve. This reduces the overall weight of the valve and end product. In the chamber used for the over pressure relief the adjustment screw is provided for adjusting the spring load precisely.
Therefore, the present invention provides an improved fuel tank isolation valve with a smaller solenoid required to operate the valve which reduces the ultimate size of valve and overall weight of the valve as well.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will be described with reference to the following drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention:
Fig. 1 is a sectional view of the fuel tank isolation valve showing the housing in accordance with the present invention.
Fig. 2(a) and Fig. 2(b) is a sectional view of the fuel tank isolation valve in idle condition in accordance with the present invention.
Figs. 3(a) and 3(b) is a sectional view of the fuel tank isolation valve in ON condition in accordance with the present invention. Figs. 4(a) and 4(b) is a sectional view of the fuel tank isolation valve working in OPR condition in accordance with the present invention.
Figs. 5(a) and 5(b) is a sectional view of the fuel tank isolation valve working in OVR condition in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings. Before explaining at least one embodiment of the invention, it is to be understood that the embodiments of the invention are not limited in their application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments of the invention are capable of being practiced and carried out in various ways. In addition, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
The present invention provides an over pressure relief (OPR) and an over vacuum relief (OVR) functions separately so that both functions are controlled independently and also provides a screw adjustment for the OPR function to control the sealing points.
In an embodiment of the present invention, an improved fuel tank isolation valve (FTIV) comprises of a valve housing and a solenoid housing. The valve housing has a canister port, a tank port, a chamber for an over pressure relief function including a first compression spring for the over pressure relief function and an adjusting screw with which a spring load is adjusted more precisely, a primary seal sub assembly for the over pressure relief function and a primary sealing surface. The over pressure relief function is provided in a separate chamber so sealing diameter for an over vacuum relief function is reduced and hence the solenoid spring force requirement is also reduced. For the over vacuum relief, a secondary seal sub assembly and a secondary sealing surface is provided in an another chamber of the valve housing. The solenoid housing comprises an electrical terminal, a second compression spring for the over vacuum relief function, a solenoid and a shaft. Therefore, a smaller solenoid is used to operate the valve. This reduces the overall weight of the valve and end product. In the chamber used for the over pressure relief the adjustment screw is provided for adjusting the spring load precisely.
Referring to Fig. 1, a sectional view of the fuel tank isolation valve showing the housing of the fuel tank isolation valve (100) in accordance with the present invention is shown. The improved fuel tank isolation valve (100) comprises a tank port (9) and a canister port (10). A chamber (14) for OPR function includes a first compression spring (4) for OPR function and an adjusting screw (7) with which spring load is adjusted more precisely, a primary seal sub assembly (5) for OPR function and a primary sealing surface (6). A second compression spring (1) for OVR function holds a secondary seal sub assembly (2) for OVR function in contact with secondary sealing surface (3) and keep the valve closed and the first compression spring (4) keeps the primary seal sub assembly (5) for OPR function in contact with the primary sealing surface (6). The adjustment screw (7) is provided in chamber used for OPR function to precisely adjust the spring load. Electrical terminal (11) is provided for electrical input to the valve for operation.
Referring to Fig. 2(a) and Fig. 2(b), a sectional view of the fuel tank isolation valve in idle condition in accordance with the present invention is shown respectively. In the idle condition, a second compression spring (1) used for OVR function holds the secondary seal sub assembly (2) for OVR function in contact with the secondary sealing surface (3) and keep the valve closed and the first compression spring (4) keeps the primary seal sub assembly (5) for OPR function in contact with the primary sealing surface (6). In idle condition, both the openings are closed and the tank port (9) is not connected to the canister port (10) of the valve till the pressure inside the tank is within the safety limit and the fuel vapours remain inside the fuel tank.
Referring to Figs. 3(a) and 3(b), a sectional view of the fuel tank isolation valve in ON condition in accordance with the present invention is shown. In On condition i.e. during refueling, solenoid of the valve will be turned ON and the moving core (12) of the solenoid moves downwards causing the secondary seal sub assembly (2) for OPR function to detach from the secondary sealing surface (3). In this way, the port gets opened and connects the tank port (9) to the canister port (10) at the time of actuation during refueling. Referring to Figs. 4(a) and 4(b), sectional view of the fuel tank isolation valve working in OPR condition in accordance with the present invention is shown. As shown in Fig. 4(a), pressure gets built inside the chamber (13) of the valve and the first compression spring (4) for OPR function keeps the primary seal sub assembly (5) for OPR function in contact with the primary sealing surface (6) keeping the valve in closed condition. As shown in Fig. 4(b), when the pressure increases beyond the protection point limit, the pressure force compresses the first compression spring (4) and lifts the primary seal sub assembly (5) for OPR function. Due to the lifting of the primary seal sub assembly (5), port gets opened and flow takes place from the tank port (9) to the canister port (10). During opening, the excess fuel vapors go to the canister port (10) and when the pressure again comes down the safety limit port gets closed.
Referring to Figs. 5(a) and 5(b), sectional view of the fuel tank isolation valve working in OVR condition in accordance with the present invention is shown. As shown in Fig. 5(a), vacuum gets built inside the chamber (13) and the compression spring (1) for OVR function keeps the seal sub assembly (2) for OVR function in contact with the sealing surface (3) of canister port (10) keeping the valve in closed condition. As shown in Fig. 5(b), when the vacuum increases beyond the protection point limit, the force by vacuum compresses the compression spring (1) and the seal sub assembly (2) for OVR function moves downwards. Due to the movement of the seal sub assembly (2), the port gets opened and flow takes place from the canister port (10) to the tank port (9). During opening, the vacuum gets released from the tank and again when the vacuum level reaches to a safety limit, the port closes.
Therefore, the present invention provides an improved fuel tank isolation valve with over pressure relief function provided in a separate chamber that has no impact on the spring load of OVR function and hence, the required solenoid spring force reduces and a smaller solenoid is required to operate the valve.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

We claim: . An improved fuel tank isolation valve (100) comprising: a) a tank port (9); b) a canister port (10); c) a chamber (14) for over pressure relief (OPR) function; d) a second compression spring (1) for over vacuum relief (OVR) function; e) a secondary seal sub assembly (2) for OVR function; f) an electrical terminal (11); g) a solenoid; and h) a shaft; wherein, said over pressure relief (OPR) function takes place separately in said chamber for over pressure relief function; said chamber (14) for over pressure relief (OPR) function includes a first compression spring (4) for OPR function, an adjusting screw (7), a primary seal sub assembly (5) for OPR function and a primary sealing surface (6); said adjusting screw (7) helps in adjusting the spring load; said secondary seal subassembly (2) and said second compression spring (1) are provided in another chamber (13); and said chamber (14) separately provided for over pressure relief function reduces sealing diameter for over vacuum relief function thereby reducing solenoid spring force requirement.
8
2. The improved fuel tank isolation valve (100) as claimed in claim 1, wherein the separate chamber (14) comprising said first compression spring (4) and said primary seal sub assembly (5) in contact with a primary sealing surface (6).
3. The improved fuel tank isolation valve (100) as claimed in claim 1, wherein an another chamber (13) comprising said second compression spring (1), and a secondary seal sub assembly (2) in contact with a secondary sealing surface (3) for an over vacuum relief function.
4. The improved fuel tank isolation valve (100) as claimed in claim 1 and 3, wherein in an idle condition opening of the tank port (9), and the canister port (10) are closed and the tank port (9) is not connected to the canister port (10) of the valve till the pressure inside the tank is within the safety limit and the fuel vapors remain inside the fuel tank.
5. The improved fuel tank isolation valve (100) as claimed in claim 1, wherein during the time of refueling, the solenoid of the valve is turned ON and the moving core (12) of the solenoid moves downwards causing the secondary seal sub assembly (2) for OPR function to detach from secondary sealing surface (3).
6. The improved fuel tank isolation valve (100) as claimed in claim 1, wherein when the pressure gets built inside the chamber (13) of the valve then the first compression spring (4) for OPR function keeps the primary seal sub assembly (5) for OPR function in contact with the primary sealing surface (6) keeping the valve in closed condition.
7. The improved fuel tank isolation valve (100) as claimed in claim 1, wherein when the pressure increases beyond the protection point limit, then the pressure force compresses the first compression spring (4) and lifts the primary seal sub assembly (5) for OPR function.
8. The improved fuel tank isolation valve (100) as claimed in claim 1, wherein when the vacuum gets built inside the chamber (13) then the compression spring (1) for OVR function keeps the seal sub assembly (2) for OVR function in contact with the sealing surface (3) of canister port (10) keeping the valve in closed condition.
9 The improved fuel tank isolation valve (100) as claimed in claim 1, wherein when the vacuum increases beyond the protection point limit, then the force by vacuum compresses the compression spring (1) and seal sub assembly (2) for OVR function moves downwards.
10
PCT/IB2021/057843 2020-08-26 2021-08-26 Improved fuel tank isolation valve to reduce solenoid size WO2022043922A1 (en)

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IN202011036820 2020-08-26

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9651002B2 (en) * 2014-09-24 2017-05-16 Ford Global Technologies, Llc Systems and methods for reducing bleed emissions
US20190168607A1 (en) * 2016-07-29 2019-06-06 Plastic Omnium Advanced Innovation And Research Ventilation flow rate regulator for a pressurised tank of a vehicle

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9651002B2 (en) * 2014-09-24 2017-05-16 Ford Global Technologies, Llc Systems and methods for reducing bleed emissions
US20190168607A1 (en) * 2016-07-29 2019-06-06 Plastic Omnium Advanced Innovation And Research Ventilation flow rate regulator for a pressurised tank of a vehicle

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