Fuel tank isolation valve with single seal, improved axis alignment and robust leak proof solenoid

Abstract

A fuel tank isolation valve 10, wherein, the shaft 18 is assembled coaxially inside hole 42 of moving plunger 46 of seal sub assembly 16 and then flow limiter 22 is guided over the shaft 18 through guiding hole 34 to maintain sealing seat 36 in parallel with respect to the sealing surface 38 of rubber seal 44 and avoid misalignment of flow limiter 22 with respect to sealing surface 38 during and after the operation; the sealing seat 36 of flow limiter 22 on the sealing surface 38 of the rubber seal 44 fixed into moving plunger 46 of seal sub assembly 16 performs the over pressure relief function; the sealing surface 40 of rubber seal 44 fixed into moving plunger 46 of seal sub-assembly 16 is resting on surface 48 of nozzle body 20 to perform over vacuum relief function; and the rubber seal 44 assist both over pressure relief (OPR) and over vacuum relief (OVR) function.

Claims

1. A fuel tank isolation valve (10), comprising: a housing sub-assembly (12) including a solenoid coil (50) and compression spring (14) for over-vacuum relief (OVR) function; a shaft (18) assembled with a seal sub-assembly (16) for inline guiding of a flow limiter (22); a nozzle body (20) provided with a plurality of mounting holes (20a) a nozzle (28) connected to a fuel tank via a fuel vapour flow path (62) and a nozzle (26) connected to a canister via a fuel vapour flow path (64), said nozzle body (20) mounted over a housing sub-assembly (12) and sealed by said seal sub-assembly (16); a compression spring (24) for over-pressure relief function fixed over the flow limiter (22) which performs over-pressure relief function; a stroke limiter (30) mounted after the flow limiter (22) and inside the nozzle body (20) to control the maximum flow by controlling operating stroke of the flow limiter (22); and a cover (32) to close the valve (10) and maintains installation height of the compression spring (24) for over-pressure relief function; wherein, the flow limiter (22) is provided with an integrated sealing seat (36) and a guiding hole (34); the seal sub-assembly (16) comprises of a plunger (46) with a guiding hole (42) and an over molded rubber seal (44) having a sealing surface (38) for over-pressure relief function and a sealing surface (40) far over-vacuum relief function; the shaft (18) maintains the sealing seat (36) in parallel with respect to the sealing surface (38) of the rubber seal (44) and avoids misalignment of the flow limiter (22) with respect to the sealing surface (38); the sealing surface (40) of the rubber seal (44) of the seal sub-assembly (16) seals with the surface (48) of the nozzle body (20); the stroke limiter (30) controlling the maximum flow by controlling operating stroke of the flow limiter (22); the solenoid coil (50) have an o-ring (52) and an o-ring (54) placed at top and bottom grooves in a way that leakage and immersion of fuel inside the solenoid coil (50) is restricted after over molding of the housing sub-assembly (12); and the solenoid coil (50) have a terminal seal (58) with a terminal pin (56) in a way that leakage and immersion of fuel inside the solenoid coil (50) is restricted by the terminal pin after over molding of the housing sub-assembly (12).

2. The fuel tank isolation valve (10) as claimed in claim 1, wherein the fuel tank isolation valve (10) obviates misalignment of over-pressure relief and over-vacuum relief sealing with respect to sealing zones and thereby avoiding fuel leakage.

3. The fuel tank isolation valve (10) as claimed in claim 1, wherein the flow limiter (22) is customized to provide a sealing seat (36) to obviate requirement of separate rubber seal required to perform the over-pressure relief (OPR) function thus reducing number of sealing points.

4. The fuel tank isolation valve (10) as claimed in claim 1, wherein guiding of the flow limiter (22) is always parallel to the sealing surface (38) of the seal sub-assembly (16) to seal and open the fuel tank isolation valve (10).

5. The fuel tank isolation valve (10) as claimed in claim 1, wherein the flow limiter (22) is coaxially guided on the shaft (18) assembled with the seal sub-assembly (16) thereby obviating misalignment of the flow limiter (22) during operation.

6. The fuel tank isolation valve (10) as claimed in claim 1, wherein the fuel tank isolation valve (10) obviates requirement of additional rubber seal required for performing the over-pressure relief (OPR) function.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIG. 1 is an exploded view of a fuel tank isolation valve (FTIV) in accordance with an embodiment of the present invention;

(3) FIG. 2 is a perspective view of flow limiter in accordance with an embodiment of the present invention;

(4) FIG. 3 is a perspective view of seal sub-assembly in accordance with an embodiment of the present invention;

(5) FIG. 4A is an exploded view, FIG. 4B is a perspective view and FIG. 4C is the sectional view showing seal sub-assembly, shaft and flow limiter in accordance with an embodiment of the present invention;

(6) FIG. 5 is a sectional view showing a housing sub assembly, a compression spring for OVR function, a seal sub-assembly, a shaft, a flow limiter, a Nozzle Body, a compression spring for OPR function and a cover in accordance with an embodiment of the present invention;

(7) FIG. 6 is a sectional view of housing sub-assembly in accordance with an embodiment of the present invention;

(8) FIG. 7 is a perspective view of terminal seal in accordance with an embodiment of the present invention; and

(9) FIG. 8A and FIG. 8B are sectional and perspective view of solenoid coil in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(10) 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.

(11) In one embodiment of present invention provides a fuel tank isolation valve (FTIV) which includes a system with lesser number of sealings and method to eliminate the misalignment of over-pressure relief (OPR) and over-vacuum relief (OVR) sealing with respect to sealing zones. Further, system and method are provided to avoid gasoline leakage and immersion into/from the fuel tank isolation valve (FTIV) body.

(12) Now referring to FIG. 1, in an embodiment of the present invention provides a fuel tank isolation valve (FTIV) 10 comprising a housing sub-assembly 12 which includes a solenoid coil inside it, a compression spring 14 for over-vacuum relief (OVR) function, a seal sub-assembly 16, a shaft 18 assembled with seat sub-assembly 16 for inline guiding of flow limiter 22, a nozzle body 20 provided with mounting holes 20a and nozzle 28 to be connected to tank and nozzle 26 to be connected to canister of the vehicle, mounted over housing sub-assembly 12 and sealed by seal sub-assembly 16, a compression spring 24 for OPR function fixed over flow limiter 22 which perform over-pressure relief function, a stroke limiter 30 mounted after flow limiter 22 inside the nozzle body 20 to control the maximum flow by controlling operating stroke of flow limiter 22 and a cover 32 to close the valve and maintains the installation height of the compression spring for over-pressure relief function.

(13) Now referring to FIG. 2, in an embodiment of present invention a flow limiter 22 is provided. Further, flow limiter 22 is provided with a guiding hole 34 for guiding of shaft 18 into it, and an integrated sealing seat 36 which perform the OPR function. Flow limiter will be assembled inside the nozzle body 20.

(14) Now referring to FIG. 3, in an embodiment of present invention, the invention provides an arrangement of seal sub-assembly 16. As shown the sealing surface 38 is for OPR function and sealing surface 40 is for OVR function of seal sub-assembly 16. Seal sub-assembly 16 also incorporates a hole 42 for assembly of the shaft 18. The rubber seal 44 is over molded on the moving plunger 46. Rubber seal 44 is a common seal far both OPR and OVR Function.

(15) Now referring to FIGS. 4A, 4B and 4C, in one embodiment of present invention provides an arrangement of seal sub-assembly 16, shaft 18 and flow limiter 22. As shown the shaft 18 is assembled coaxially inside hole 42 of moving plunger 46 of seal sub assembly 16 and then flow limiter 22 is guided over the shaft 18 through guiding hole 34 in such a way as to maintain the parallelism of sealing seat36 with respect to the sealing surface 38 of rubber seal 44 during and after the operation. Further, this helps in overcoming the problem of misalignment of flow limiter 22 with respect to sealing surface 38 during and after the operation.

(16) Now referring to FIG. 5, in an embodiment of present invention, the invention provides arrangement of housing sub-assembly 12, seal sub-assembly 16, shaft 18, nozzle body 20 and flow limiter 22 within the fuel tank isolation valve 10 (FTIV). Housing sub-assembly 12 incorporates a seal sub-assembly 16 with a compression spring 14. A nozzle body 20 is attached to housing sub-assembly 12 along with seal sub-assembly 16 and compression spring 14 by means of such as, but not limited to laser welding, etc. wherein sealing surface 40 of rubber seal 44 seals with sealing surface 48 of nozzle body 20 thus blocks the fuel vapor flow path 62 of nozzle 28 to perform over-vacuum relief function. Further, a flow limiter 22 having an integrated sealing seat 36 is inserted into shaft 18, integrated sealing seat 36 is in contact with sealing surface 38 of rubber seal 44 to perform over-pressure relief function by creating a block to fuel vapor flow path 64 of nozzle 26. A stroke limiter 30 and another compression spring 24 is mounted over flow limiter 22 to control the maximum flow by controlling operating stroke of flow limiter 22. A cover 32 is fixed to nozzle body 20 by means of such as, but not limited to laser welding, etc. to make fuel tank isolation valve 10 (FTIV) a closed leak proof assembly. During the operation of FTIV 10, the flow limiter 22 always move on the same axis of seal sub assembly 16 as they are guided on by the shaft 18 which is coaxially assembled with the seal sub assembly 16.

(17) Now referring to FIG. 6, in an embodiment of present invention provides a housing sub-assembly 12 which is generally circular in shape and includes a solenoid coil 50 with terminal pins 56 inside it. As shown, o-ring 52 and o-ring 54 are placed at top and bottom grooves of the solenoid coil 50 in such a way that leakage and immersion of fuel inside solenoid coil 50 is restricted.

(18) Now referring to FIG. 7, in an embodiment of present invention provides a terminal seal 58 made up of a rubber material which incorporates holes 60 for terminal pin 56. This, terminal seal 58 restricts the immersion of fuel into the solenoid coil 50 from electrical terminals.

(19) Now referring to FIGS. 8A and 8B, in an embodiment of present invention provides an arrangement of terminal seal 58 with terminal pin 56 of solenoid coil 50. O-ring 52 and o-ring 54 is placed inside their respective grooves of solenoid coil 50 in such a way that leakage and immersion inside solenoid coil 50 is restricted after over molding and making it a robust leak proof design.

(20) 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.