Shutoff valve for vehicle fuel tank

Abstract

A fuel refill system shutoff valve is provided for a fluid delivery system which provides internal pilot lines for use with a jet fluid level sensor. The shutoff valve is closed unless there is a positive signal from the return pilot line, so the shutoff valve fails in the closed position and avoids the situation where a failure leads to over-filling of the tank. An internal piston opens and closes peripheral fluid outlets based on the presence and / or absence of back pressure provided by the return signal of a fluid level sensor located inside the fuel tank of a vehicle.

Description

SHUTOFF VALVE FOR VEHICLE FUEL TANKBACKGROUND

[0001] This invention relates generally to a refueling system for a vehicle, and more specifically to a fuel tank shutoff valve for use with a system which uses a fluid level sensor with pilot lines located inside the fuel tank.

[0002] Some large vehicles have high capacity fuel tanks holding up to 1200 gallons or more, and these high capacity tanks utilize rapid fill systems to quickly transfer fuel to fill the large volume of the tanks. Refueling receivers commonly work in conjunction with fast fill automatic shutoff nozzles that require tank back pressure build up in order for them to activate shutoff. In order to use a pressurized refueling system, the fuel tanks have to be structurally designed to withstand internal pressures of up to 10 psi, so that such fuel tanks typically are not appropriate for use in lighter vehicles.

[0003] Some high capacity refueling systems involve filling a fuel tank with a release or spill valve that allows excess fuel to spill out of the tank when it is full, indicating to an operator to manually shut off the flow of fuel. However, operators tend to force automatic shutoff nozzles open in order to completely fill pressurized tanks, resulting in frequent fuel spills through an overflow valve or vent. In addition, should a nozzle shut off valve and a tank overflow valve fail at the same time, excessive pressure in the fuel tank can cause the tank to suffer a catastrophic structural failure.

[0004] For non-pressurized tank refueling, it has been found that a conventional jet sensor used to sense a fuel level and automatically shut off flow of fuel through a fuel receiver commonly transmits a significant residual hydraulic signal even when the jet sensor is fully submerged in fuel, such as when the fuel tank is completely full. It has been desirable to minimize any residual fluid flow signal when the sensor is fully submerged in order to allow a flow control valve in the fuel receiver to close completely. In addition, non-pressurized refueling systems typically make use of a single signal hose and a hydraulic signal that is controlled by a float valve, so that if the single signal hose is damaged or detached, or if the float valve fails to completely seat, the main fuel flow typically will not shut off and tank overflow can occur. It is therefore desirable to provide a closed-loop non-pressurized refueling shut off system, so that in the event a signal hose is damaged or detached, the system will fail in a safer condition preventing overfill and over-pressurization of the tank. Itis also desirable to provide a non-pressurized refueling shut off system having a jet sensor with substantially no moving parts, is less susceptible to wear, and even if damaged, would result in an inability to fill the tank, which is a safer condition than if fuel flow into the tank could not be stopped.

[0005] The cost of fuel lost through fuel spills and recent environmental laws make it desirable to avoid fuel spills at refueling stations, such that it would be desirable to provide an automated fuel delivery system for large vehicles which is capable of properly filling fuel tanks and that can avoid the risks of fuel spills and over-pressurization of fuel tanks. The present invention addresses these and other desirable needs.SUMMARY OF THE INVENTION

[0006] The present invention is a shutoff valve for a fluid delivery system that provides internal pilot lines for use with a jet fluid level sensor. The shutoff valve is closed unless there is a positive signal from the return pilot line, so the shutoff valve fails in the closed position and avoids the situation where a failure leads to over-filling of the tank. An internal piston opens and closes peripheral fluid outlets based on the presence and / or absence of back pressure provided by the return signal of a fluid level sensor located inside the fuel tank of a vehicle.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is an elevated, perspective view of a prior art fuel tank and sensor arrangement;

[0008] FIG. 2 is a side view diagram of a fuel tank and sensor of the present invention;

[0009] FIG. 3 is a cross sectional side view of the shutoff valve of the present invention in the closed configuration; and

[0010] FIG. 4 is a cross sectional side view of the shutoff valve of the present invention in the open configuration.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Figure 1 illustrates a fuel tank refilling system of the prior art, such as the JN 125 system offered by AdelWiggins Group: https: / / www.transnet.net / DropOffLibrary / Annexure%2014%20Rolling%20Stock%20Specifi cation%20-%20Fuel%20Nozzle.pdf. In the system depicted in Figure 1, the tank is supplied with fuel by the nozzle connected to a pressurized supply of fuel and introduced into the tank at a fuel receiver disposed on the peripheral wall of the tank. Reference is made to United States Patent No. 9,458,006 for a background and operation of the fuel system, the content of which is fully incorporated herein by reference. Located adjacent the upper surface of the tank is a fuel level sensor that determines when the fuel in the tank is approaching the maximum fill capacity. The sensor is connected to the fuel receiver such that when the sensor determines that the maximum capacity is achieved, a signal from the sensor to the receiver results in the termination of the filling operation and prevents overfilling and / or spillage. The pick-up and return pilot lines are located outside the tank and run along the exterior surface of the tank.

[0012] Figure 2 illustrates a first embodiment of a fuel refilling system of the present invention. A fuel tank 10 is shown in cross section with a fuel level sensor 12 and a fuel shutoff valve 13. The fuel level sensor is described in US Provisional Patent Application No. 63 / 606,593, the content of which is incorporated herein by reference. The level sensor and the shutoff valve communicate via first and second pilot lines, specifically a primary or signal pickup line 14 and a return line 16. It is immediately apparent that both pilot lines 14, 16 (signal pickup and return) connecting the level sensor 12 and the shutoff valve 13 have been relocated inside the fuel tank 10 and connect to the fuel source within the tank’s interior space 15. The positioning of the pilot lines 14, 16 inside the tank’s interior 15 eliminates the existence of pressurized fuel lines outside of the tank 10, resulting in a system having increased fire prevention capability. Moreover, there is less opportunity for the lines to suffer damage, wear, etc. within the protection of the tank.

[0013] Figure 3 illustrates a shutoff valve 13 of the present invention in the closed condition. The shutoff valve of the present invention defaults to the closed position, so fuel cannot pass through the valve and enter the tank unless a hydraulic return signal is present from the return pilot line 16, unlike other shutoff valves that fail or default to an open condition. The valve 13 is connected to the tank 10 via a collar 132 retained by fasteners 134.The valve 13 has a nipple 118 with an internal cavity 128 and a closure mechanism described below.

[0014] A pressurized fuel source is necessary to open the valve 13 by retracting the piston 122 against the closing force of the spring 124 in piston housing 126. The pressure of the incoming fuel moves the piston 122 away from the inlet 110 and into the cavity 128 to allow fuel to enter the inlet 1 10 of the valve 13. Fuel entering the inlet 110 moves around the closure mechanism and directly into the chamber 112, pressurizing the chamber. Chamber 112 includes apertures 142 (see Figure 2) that open to the tank’s interior 15.

[0015] Internal cylinder 150 can translate axially within the chamber 112. When the internal cylinder 150 is in the position shown in Figure 3, the apertures 142 are occluded by the distal walls 139 of the internal cylinder, preventing fuel from exiting the valve 13 through the apertures 142. The pressure from the incoming fuel that fills the chamber 112 biases the internal cylinder 150 distally to the position shown in Figure 3, and thus in the presence of incoming fuel, the apertures are blocked by the internal cylinder 150 and the valve defaults to the shut or closed condition.

[0016] The valve body 115 houses an annular fitting 117 distal of the apertures 142. The annular fitting 117 includes a central passage that receives a shaft 119. Shaft 1 19 is part of a piston 121 translating axially within cavity 125. Spring 127 within cavity 125 bears against annular fitting 117 and operates to bias the piston 121 distally as shown in Figure 3 against a rear wall 161. The proximal end of shaft 119 is received in an aft-facing recess in the internal cylinder 150. With the piston 121 at the distal position shown in Figure 3, the internal cylinder 150 is positioned such that the apertures 142 are blocked, preventing fuel from leaving the valve.

[0017] The presence of fuel in the valve 13 pressurizes the chamber 112. A fuel signal passage 143 is formed in the annular fitting 117 and continues in the valve body 115, leading to a fuel signal stem 151. The fuel system stem 151 receives the pilot line 14 to communicate a stream of pressurized fuel to the level sensor 12. The return pilot line 16 is received by the fuel signal return stem 153, which is in fluid communication with a back pressure compartment 155. When there is no fuel pressure in the return pilot line, there is no elevated pressure in the back pressure compartment 155 as shown in Figure 3 and the spring 127 pushing the piston 121 is unopposed, moving the piston distally as shown.

[0018] Figure 4 illustrates the valve 13 in the open condition when an elevated pressure is present in the pilot return line 16. This occurs when the fluid level in the tank has not reached the maximum fluid level determined by the sensor 12. In the open condition of Figure 4, fluid pressure moves the piston 112 inward, overcoming the biasing of the spring 124. Fuel (represented by arrows 167) moves around the piston 122 and the piston housing 126, into chamber 112.

[0019] The fluid pressure arising from the return pilot line 16 causes fluid to fill the back pressure compartment 155, which in turn pushes the piston 121 axially forward toward the nipple 118 (against the bias of the spring 127). The movement of the piston 121 causes the shaft 119 of the piston 121 bearing against the internal cylinder 150 to move the internal cylinder 150 away from the apertures 142 so that the apertures are no longer occluded, allowing fuel 167 to flow over the vane 157 and be directed out through the apertures 142 to fill the tank 10. As long as the fluid level sensor 12 is uninterrupted (i.e., the fluid level has not reached the sensor’s critical height), a return flow line 16 will maintain a back pressure to keep the valve 13 open. Should the sensor 12 fail or should something happen to the sensor, the return line would lose pressure. The absence of back pressure in back pressure compartment 155 leads to the spring 127 moving the piston 121 aft and causes the internal cylinder 150 to slide rearward to block the apertures 142. Thus, the valve is closed automatically in the absence of a return back pressure signal. In this manner, the shutoff valve provides internal ports for a primary and return pilot line and the operation of the valve closes in a failed fluid level condition.

[0020] Although the foregoing describes and depicts a shutoff valve for rapid refueling, the invention is not limited to the embodiments depicted in the figures and the foregoing description, which merely sets forth the inventors’ preferred embodiments. A person of ordinary skill in the art would readily recognize and appreciate various modifications and substitutions, and the scope of the invention properly includes all such modifications and substitutions.

Claims

We Claim:

1. A fluid shutoff valve, comprising: a valve body having a peripheral outlet; a first piston blocking an inlet of the valve body in the absence of a pressurized flow into the valve body; an internal cylinder configured for axial translation within the valve body, said internal cylinder having a first position occluding the peripheral outlet and a second position spaced from the peripheral outlet; a second piston configured for axial translation within the valve body, said second piston including a shaft coupled to the internal cylinder via an aft-facing recess; an annular fitting disposed within the valve body, said annular fitting including a central hole receiving the shaft therein through; a fluid signal stem; a fluid signal return stem; a first fluid signal passage defining a fluid path through the annular fitting and the valve body to the fluid signal stem; and a back pressure compartment in fluid communication with the fluid signal return stem; wherein fluid flow through the fluid signal return stem creates a back pressure in the back pressure compartment; and wherein said back pressure causes the second piston to move the internal cylinder into the second position to allow fuel through the peripheral outlet.

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