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Title:
COMPACT FUEL TANK ISOLATION VALVE WITH SPRING LOAD ADJUSTMENT FOR PRECISE CONTROL OF SEALING POINT
Document Type and Number:
WIPO Patent Application WO/2022/024077
Kind Code:
A1
Abstract:
The present invention relates to an improved fuel tank isolation valve. More particularly, the present invention relates to an improved fuel tank isolation valve (10) for maintaining the tank pressure within the protected pressure range, controlling the fuel vapors flow from tank port (14) to canister port (13) during refueling and inline function of over pressure relief and over vacuum relief which is a compact design with less weight and cost and provides precise controlled flow. The mechanical opening points in the over pressure condition are controlled with the help of mechanical compression springs (4).

Inventors:
BHANDARI KABIR (IN)
KUMAR AMARDIP (IN)
KUMAR VARUN (IN)
SINGLA SAHIL (IN)
Application Number:
PCT/IB2021/056995
Publication Date:
February 03, 2022
Filing Date:
July 30, 2021
Export Citation:
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Assignee:
PADMINI VNA MECHATRONICS PVT LTD (IN)
International Classes:
F16K15/00; F02M25/08
Domestic Patent References:
WO2019030243A12019-02-14
Foreign References:
EP3462066A12019-04-03
US9500291B22016-11-22
Attorney, Agent or Firm:
AMBASTHA, Lalit et al. (IN)
Download PDF:
Claims:
CLAIMS

We claim:

1. An improved fuel tank isolation valve (10) comprising: a valve housing (11) with a canister port (13) and a tank port (14) and enclosing a seal sub assembly (28) for OVR function and a seal (24) for OPR function; a solenoid housing (12) comprising a compression spring (1) for OVR function, a compression spring (4) for OPR function, a fix core (6), a moving core (7), a guiding rod (2) and a solenoid (20); a seal (25) for OVR function; wherein, said seal (24) for OPR function is having a radial portion (8) and a shaft portion (9) extending downwards; said moving core (7) has a cylindrical groove (15, 16) at its center of uniform diameter on its upper and lower side; said shaft portion (9) of the seal (24) is inserted in cylindrical groove (15) and the compression spring (4) for OPR function is installed at a desired height that adjusts spring (4) installation load to a target value to achieve targeted opening point in the valve (10); and said valve (10) controls mechanical opening points in the over pressure condition with compression springs (1, 4).

2. The valve (10) as claimed in claim 1, wherein said valve (10) has a sealing area (5) formed when seal (24) for OPR function mates with inner rim of seal (25) for OVR function to provide sealing for OPR function and refueling.

3. The valve (10) as claimed in claim 1, wherein said valve (10) has a sealing area (3) formed when the outer rim of seal (25) for OVR function is extended to contact with a sealing surface (27).

4. The valve (10) as claimed in claim 1, wherein said shaft portion (9) has a bottom portion with a diameter lesser than the rest of the length of shaft portion (9).

5. The valve (10) as claimed in claim 1, wherein said shaft portion (9) at its bottom portion has radial bush (17) installed to support the compression spring (4) for OPR function.

6. The valve (10) as claimed in claim 1, wherein said valve (10) is having a reduced size with balanced manufacturing tolerances.

Description:
“COMPACT FUEL TANK ISOLATION VALVE WITH SPRING LOAD ADJUSTMENT FOR PRECISE CONTROL OF SEALING

POINT”

FIELD OF THE INVENTION

The present invention relates to an improved fuel tank isolation valve. More particularly, the present invention relates to an improved fuel tank isolation valve for maintaining the tank pressure within the protected pressure range, controlling the fuel vapors flow from tank port to canister port during refueling and inline function of over pressure relief and over vacuum relief which is a compact design with less weight and cost and provides precise controlled flow.

BACKGROUND OF THE INVENTION

In vehicles having pressurized tank system, there is a need to install a valve which can maintain the pressure inside the tank in a protected pressure range either in an over pressure condition or in an under pressure (over vacuum) condition. 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 & whereas other port of the valve is connected to canister of the vehicle. 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.

The most obvious solution, to overcome the problem is to provide 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 valve is electrically actuated at the time of refueling. The fuel tank isolation valve (FTIV) also enables fuel vapor containment in the fuel tank until conditions are inappropriate for the engine to process the excess vapor. Generally, the fuel tank isolation valve includes an electrically controlled solenoid valve to open and close the inlet and outlet port with either less precise control on opening of intermediate positions or no control of opening on intermediate positions. Thus, have no precise control of flow of fuel vapors from fuel tank to canister at the time of refueling and no balancing between the mechanical parts of the valve.

CN104343585B teaches a method and system of the fuel tank isolation valve for controlling the fuel tank being coupled in vehicle. In response to the request that refuels, driving fuel tank isolation valve makes fuel tank vent for refueling; and in response to pressure in fuel tank is lower than threshold pressure after predefined duration, stops the driving of fuel tank isolation valve to seal fuel tank. The invention does not suggest controlling the mechanical opening points with help of mechanical compression springs. Hence, it is difficult to achieve targeted opening points.

Therefore, the present invention provides an improved fuel tank isolation valve with an adjustment mechanism of the compression spring that will lead to compact design, precise functional control, cost effective, less weight and reduced number of components in the overall assembly.

OBJECT OF THE INVENTION

The main object of the present invention is to provide an improved fuel tank isolation valve for maintaining the tank pressure within the protected pressure range, controlling the fuel vapors flow from tank port to canister port during refueling and performing inline function of over pressure relief and over vacuum relief which is a compact design with less weight and cost and provides precise controlled flow.

Another object of the present invention is to provide an improved fuel tank isolation valve wherein the spring installation load is maintained at a target value to get the desired performance of the valve in over pressure condition.

Yet another object of the present invention is to provide an improved fuel tank isolation valve which is robust and compact as all the functions provided are in line to each other. Yet another object of the present invention is to provide an improved fuel tank isolation valve wherein the mechanical opening points in over pressure condition are controlled by the mechanical compression springs in which spring is installed at a height to achieve the targeted opening point in the valve.

Still another object of the present invention is to provide a fuel tank isolation valve which is light weight and has reduced size.

SUMMARY OF THE INVENTION

The present invention provides an improved fuel tank isolation valve (FTIV) in which mechanical opening points are controlled with the help of mechanical compression springs wherein the spring (OPR) is installed at a height to achieve the targeted opening point in valve. The valve performs inline function of over pressure relief (OPR) and over vacuum relief (OVR).

In an embodiment of the present invention, an improved fuel tank isolation valve comprises of a valve housing and a solenoid housing, wherein the valve housing has a canister port and a tank port fitted over the solenoid housing, the valve housing includes a seal sub assembly for OVR function, a seal for OPR function; and the solenoid housing includes a compression spring for performing OVR function, a compression spring for performing OPR function and a solenoid. The improved fuel tank isolation valve maintains pressure within a protected pressure range, provide electric control of fuel vapors flow from tank to canister during refuelling, provide over pressure relief and over vacuum relief function. The valve having compression spring for performing OPR function is installed at a height to achieve the targeted opening of said valve. The compression spring for OPR function controls the mechanical opening points in over pressure condition.

Therefore, the present invention provides a light weighted improved fuel tank isolation valve having reduced size which is efficient in precisely balancing the manufacturing tolerances.

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(a) shows a sectional view of the fuel tank isolation valve showing the housing in accordance with the present invention.

Fig. 1(b) shows a sectional view of the fuel tank isolation valve in accordance with the present invention.

Fig. 1(c) shows a sectional view of the fuel tank isolation valve showing the sealing in accordance with the present invention.

Figs. 2(a) and 2(b) show a sectional view of the fuel tank isolation valve in the idle condition in accordance with the present invention.

Figs. 3(a) - 3(c) show a sectional view of the fuel tank isolation valve in the ON condition in accordance with the present invention.

Figs. 4(a) - 4(c) show a sectional view of the fuel tank isolation valve working in OPR condition in accordance with the present invention.

Figs. 5(a) - 5(c) show 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 improved fuel tank isolation valve with a compression spring installed at a height to achieve the targeted opening in valve and inline function of over pressure relief (OPR) and over vacuum relief (OVR).

Referring to Fig. 1(a), a sectional view of the fuel tank isolation valve showing the housing of the fuel tank isolation valve (10) in accordance with the present invention is shown. The fuel tank isolation valve comprises of a valve housing (11) fitted over a solenoid housing (12), wherein the valve housing (11) comprises of a canister port (13) and a tank port (14).

Referring to Fig. 1(b), a sectional view of the fuel tank isolation valve (10) in accordance with the present invention is shown. The fuel tank isolation valve (10) comprises of a valve housing (11) and a solenoid housing (12). The valve housing (11) comprises of a canister port (13) and a tank port (14). A seal (25) for OVR function is installed in the tank port (14) to connect to fuel tank. A seal (24) for OPR function is provided. In the fuel tank isolation valve (10) there is a compression spring (4) for OPR function and a compression spring (1) for OVR function is fitted over a seal (25) for OVR function. Said solenoid housing (12) further encloses a fix core (6), a moving core (7) and a guiding rod (2). The solenoid housing (12) comprises of a compression spring (1) and a solenoid (20). Referring to Fig. 1(c), an enlarged sectional view of the fuel tank isolation valve (10) is shown in accordance with the present invention is shown. The sealing area (5) is formed when seal (24) for OPR function mates with inner rim of seal (25) for OVR function to provide sealing for OPR function and refueling. Also, the outer rim of seal (25) for OVR function is extended to form sealing area (3) when in contact with the sealing surface (27) to provide sealing for OVR function. Seal (24) for OPR function has a radial portion (8) at the top and a shaft portion (9) extending downwards from the centre of radial portion (8). The shaft portion (9) is such that it has a bottom portion of a diameter lesser than the rest of the length and a radial bush (17) is installed at this portion to support the compression spring (4). Said moving core (7) has a cylindrical groove (15, 16) at the centre of uniform diameter at its upper side as its lower side. Said shaft portion (9) of the seal (24) is inserted in cylindrical groove (15) and the compression spring (4) for OPR function is installed at a desired height using a radial bush (17) where the targeted opening point is desired.

Referring to Figs. 2(a) and 2(b), a sectional view of the fuel tank isolation valve (10) in idle condition in accordance with the present invention is shown respectively. In the idle condition, the compression spring (1) for OVR function holds the seal subassembly (28) for OVR function upwards and attached with the sealing surface (27) and keeps the valve closed. On the other hand, the compression spring (4) keeps the seal (24) for OPR function in contact with the seal (25) for OVR function to form sealing area (5). Hence, both the openings for OVR and OPR are closed and canister port (13) of the valve is not connected to the tank port (14) of the valve. In the idle condition, the fuel vapors remain inside the fuel tank till the pressure inside the tank is within safety limit.

Referring to Figs. 3(a) - 3(c), a sectional view of the fuel tank isolation valve in ON condition during refueling in accordance with the present invention is shown. During refueling, the solenoid (20) is turned on and due to magnetic field; the moving core moves downward causing seal (25) for OVR function to open and seal (24) for OPR function to remain in its position. The moving core (7) force due to magnetic field is greater than the force exerted by compression spring (1) for OVR function and due to the magnetic force, the moving core (7) moves downward and seal (25) for OVR function detaches from the sealing surface (27) as depicted in Fig. 3(b). In ON condition, the port is open and the tank port is connected to the canister port at the time of actuation during refueling as depicted in Fig. 3(c).

Referring to Figs. 4(a) - 4(c), sectional view of the fuel tank isolation valve (10) working in OPR condition in accordance with the present invention is shown. When the fuel tank isolation valve (10) is in OPR condition, there is a pressure built up inside the valve (10) in the chamber (17) of the valve (10) and compression spring (4) for OPR function keeps the seal (24) for OPR function in contact with the sealing surface (27) keeping the fuel tank isolation valve (10) in closed condition as depicted in Fig. 4(a). When the pressure increases beyond a predefined protection point limit, the pressure exerts a force to compress the compression spring (4) for OPR function and lifts the seal (24) for OPR function upwards as depicted in Fig. 4(b). As the seal (24) for OPR function lifts up, valve opens, and flow starts from tank port (14) to canister port (13) as depicted in Fig. 4(c). The excess fuel vapors go to canister and the pressure starts dropping. As soon as the pressure drop reaches to protection point limit i.e. safety limit, valve closes again.

Referring to Figs. 5(a) - 5(c), sectional view of the fuel tank isolation valve (10) working in OVR condition in accordance with the present invention is shown. When the fuel tank isolation valve (10) is in OVR condition, there is a vacuum built up inside the valve (10) in the chamber (17) of the valve (10) and compression spring (1) for OVR function keeps the seal (25) for OVR function in contact with the sealing surface (27) to keep the fuel tank isolation valve (10) in closed condition as depicted in Fig. 5(a). When the vacuum increases beyond the protection point limit, vacuum exerts a force to compress the compression spring (1) and the seal (25) for OVR function moves downwards. In OVR condition, the seal (25) for OVR function moves that leads to opening of ports and flow happen from canister port (13) to tank port (14). During opening, the vacuum releases from tank and as soon as the vacuum reaches the protection limit, the port is closed.

Due to lower tolerance band of specification of opening point, the desired spring load has a very low manufacturing tolerance band that is difficult to maintain in manufacturing. Therefore, the present invention provides a light weighted improved fuel tank isolation with a spring (OPR) installation load maintained at a target value to get the desired performance of the valve. The improved fuel tank isolation valve is efficient in precisely balancing the manufacturing tolerances. The mechanical opening points in the over pressure condition are controlled with the help of mechanical compression springs.

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.