Patent Publication Number: US-2018037107-A1

Title: Manual emergency gas release system

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 15/014,933, filed on Feb. 3, 2016, which claims the benefit of U.S. Provisional Application No. 62/112,573, filed on Feb. 5, 2015, the entirety of each of which are incorporated by reference herein and made part of this specification. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This application relates to techniques to enhance safety of vehicles powered by fuels that are stored at high pressure. 
     Description of the Related Art 
     One approach to improve automotive emissions is to power automobiles with cleaner fuels such as natural gas. When used as an automobile fuel source, natural gas is stored in specialized tanks at high pressure. This allows an automobile powered by natural gas to have greater range. Certain precautions have been developed to address safety concerns with storing natural gas at high pressure. In one approach, a thermally activated pressure relief device (PRD) is coupled with the tank to vent the contents in the event of a fire. The PRD can open a valve to vent the canister if a thermal threshold is exceeded. 
     SUMMARY OF THE INVENTION 
     A need exists to provide an additional venting system that can be manually operated by a vehicle operator or a first responder in the case of an emergency. Such a system would further enhance safety of vehicles with high pressure fuel tanks. 
     In one embodiment, a manual venting system is provided that allows an operator to manually vent fuel tanks, such as compressed natural gas cylinders or liquid natural gas cylinders, in case of a fire before the thermally activated Pressure Relief Devices (PRDs) have opened. PRDs include valves based on different designs, in each case opening after being exposed to heat. Some PRDs are designed to open when the heat melts a eutectic material or a glass bulb upon reaching a predetermined temperature to provide fluid communication across the valve. Other PRDs are designed to open when a wire inside of a sheath shrinks with heat until the device reaches a pre-determined set point where the wire is activated to pull a vent valve open. In general, conventional PRDs have a lag between when heat begins to be applied and when the valve opens. In various embodiments, the operator of a vehicle would have a safety button or other actuator inside the cab of the vehicle. When the button is depressed a relief valve is opened to vent all of the gas stored inside the on board storage tanks. 
     In one embodiment, a vehicle fuel system is provided that includes a fuel tank and a manual vent system. The manual vent system includes an emergency valve and an actuator. The manual vent system is configured to cause the emergency valve to open after the actuator has been actuated. 
     In one embodiment a mechanical connection is provided between the actuator and a relief valve. The mechanical connection can be provided by a cable routed from a location inside the cab of the vehicle to the relief valve at the tank or tanks. The cable can have a first end disposed adjacent to or in the cab and a second end disposed adjacent to or on the tank. The cable preferably is protected in a sleeve that has an inner periphery greater than the outer periphery of the cable. A gap between the inner and outer periphery enables the cable to slide such that the relief valve can be actuated upon such sliding. A handle in the cab can be connected to the first end of the cable. 
     A cover can be provided over the handle to prevent inadvertent activation of the relief valve. 
     In another embodiment, an electrical signal conveyance is provided for communicating a manual signal to open a relief valve to the relief valve. The signal conveyance can include a button configured to provide a signal to an electronic control unit (ECU) of a fuel system and/or a wire connecting the button to an electromechanical device adapted to open a valve. A suitable mechanism for opening the valve can include a solenoid, for example. The button can be electrically coupled by a wire to the ECU. The button can be coupled by a wireless transmitter to the ECU. The button can be located in the cab of the vehicle with which the fuel system is coupled. The button can be accessible from outside the vehicle, for example by a first responder in the case of emergency. 
     Where provided, an electrical wire can be enclosed in a fire resistant structure, such as a high temperature insulator. 
     In certain variations, a secondary actuator can be provided. The secondary actuator can be disposed adjacent a valve to vent the tank in certain conditions. The secondary actuator can be configured to open the valve when actuated. The secondary actuator can employ a mechanism and not an electrical conveyance. For example, a lever can act on a blocking structure of a valve to move the blocking structure away from a seating surface to cause the valve to be in an open state. 
     In another embodiment, a vehicle is provided that includes a chassis and a fuel system. The fuel system is coupled with the chasse. The fuel system includes a fuel tank and a manual vent device. The manual vent device includes an emergency valve, an actuator, and a connector disposed between the actuator and the emergency valve actuator. The connector is responsive to actuation of the actuator to cause the emergency valve to open. The connector has an accessible portion disposed along a surface of the vehicle. Severing the connector at the accessible portion causes the emergency valve to open. 
     The manual venting system can be integrated into a fuel system in some embodiments. In some embodiments, the manual venting system is integrated into a vehicle. In some embodiments, the manual venting system is a separate system that can be added to vehicles already in service. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The abovementioned and other features of the inventions disclosed herein are described below with reference to the drawings of the preferred embodiments. The illustrated embodiments are intended to illustrate, but not to limit the inventions. The drawings contain the following figures. 
         FIG. 1  is a side view of a vehicle having a fuel system mounted to the vehicle behind the cab, sometimes known as a back-of-cab mounted fuel system; 
         FIG. 2 a    is a side view of a vehicle having a rail mounted fuel system; 
         FIG. 2 b    is a side view of a vehicle having a roof mounted fuel system; and 
         FIG. 2 c    is a side view of another vehicle having a roof mounted fuel system. 
         FIG. 3  is an alternative embodiment with a primary release mechanism and a secondary release mechanism. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the present description sets forth specific details of various embodiments, it will be appreciated that the description is illustrative only and should not be construed in any way as limiting. Furthermore, various applications of such embodiments and modifications thereto, which may occur to those who are skilled in the art, are also encompassed by the general concepts described herein. Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent. 
     Improved venting systems and devices are disclosed herein in which users are able to activate a valve immediately to reduce pressure in or completely evacuate a fuel tank. These devices and systems can be activated when it is undesirable to wait for a conventional pressure relief device to open. 
       FIG. 1  is a schematic of a vehicle  100  with a fuel system  110  and a manual vent system  200  coupled therewith. The vehicle  100  may be any type of vehicle known in the art. The vehicle  100  may be a truck, such as a light duty truck (e.g., class 1, class 2 or class 3), medium duty truck (e.g., class 4, class 5 or class 6), or heavy-duty truck (e.g., class 7 or class 8). In some embodiments, the vehicles may be cars, wagons, vans, buses, high-occupancy vehicles, dump trucks, tractor trailer trucks, transit, refuse or heavy-duty vehicles, or any other vehicles. The vehicle may have any weight. For example, the vehicle may weigh more than or equal to about 5000 lbs, 7,500 lbs, 10,000 lbs, 12,500 lbs, 15,000 lbs, 17,500 lbs, 20,000 lbs, 22,500 lbs, 25,000 lbs, 30,000 lbs, or 35,000 lbs. In some cases, the vehicle may have a weight up to or exceeding 80,000 lbs. 
       FIG. 1  illustrates the fuel system  110  mounted to the vehicle  100  in a behind-the-cab or back-of-cab configuration. In the behind-the-cab configuration, the fuel system  110  may be installed behind the cab C on the vehicle frame, providing, for example, standard fuel capacities, measured in diesel gallon equivalents (DGE), of 45 DGE, 60 DGE, 75 DGE or 100 DGE. In certain configurations, the fuel system  110  can be configured to provide 180 DGE or more. The fuel system  110  may be mounted to the vehicle in other configurations. For example,  FIG. 2 a    shows a side-mount configuration with the fuel system  110  installed on the side of the vehicle frame. Fuel systems may be installed on one or both sides of the vehicle, providing, for example, standard fuel capacities of 40 DGE, 60 DGE, 80 DGE, 100 DGE, or 120 DGE or more.  FIGS. 2 b  and 2 c    illustrate two examples of roof mounted systems. In further examples, the fuel system  110  may be installed in a custom integration, providing a wide range of customizable fuel capacities. In an additional example, in a front-of-the-body configuration, the fuel system  110  may be installed in front of the vehicle body, providing, for example, standard fuel capacities of 60-100 DGE. A variety of mounting locations on the vehicle frame are possible. 
     The vehicle  100  may be propelled by a fuel, including, but not limited to, compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG), Diesel fuel, gasoline, dimethyl ether (DME), methanol, ethanol, butanol, Fischer-Tropsch (FT) fuels, hydrogen or hydrogen-based gas, hythane, HCNG, syngas and/or other alternative fuels or fuel blends. For example, natural gas in the form of CNG or LNG may be an alternative fuel of choice for transit, refuse, and many other heavy-duty vehicles. 
     The fuel may be stored as a compressed gas, as a liquefied gas or as a liquid under its own vapor pressure. The fuel may be stored in the fuel system  110  comprising a fuel tank  114 . The fuel tank can be a cylinder or any other type of device capable of containing a fuel in compressed gas, liquefied gas or liquid form. 
     The fuel tank  114  may be configured in accordance with the chosen fuel storage mode. For example, compressed gases, such as CNG, may require that the fuel tank  114  be outfitted with adequate high pressure components (e.g., high pressure seals, standard operation relief valves, compression devices), wherein high-strength and lightweight materials may allow CNG pressures up to, for example, 3,600 psig. In another example, liquefied gases, such as LNG, may require that the fuel tank  114  be outfitted with adequate liquefaction components (e.g., coolers, liquid-vapor separators, insulation). LNG systems may operate at pressures of, for example, 0 psig, 50 psig, 100 psig, 150 psig, 200 psig, 250 psig, 300 psig, or 350 psig and temperatures of, for example, −259° F., −223° F., − 200 ° F., −186° F., −175° F., −167° F., −158° F., or −150° F., requiring the use of cryogenic (about −260° F.) piping systems and vacuum-insulated storage tanks. 
     In some embodiments, the vehicle  100  may include a single fuel tank  114 . In other embodiments, the vehicle  100  may contain a plurality of fuel tanks  114 . The tanks may or may not have the same characteristics. The tanks may be mounted to any portion of the vehicle. In some embodiments, the tanks may be mounted to a side of the vehicle. One, two, or more tanks may be mounted on a single side of the vehicle, or on each side of the vehicle. The side-mounted tanks may at least partially protrude from a side surface of the vehicle. 
     The one or more fuel tanks  114  may provide storage for a predetermined amount, or capacity, of fuel. For example, for natural gas measured in diesel/gasoline gallon equivalents (where 1 gasoline gallon equivalent (GGE)=standard cubic feet (SCF) of natural gas divided by 123, and 1 diesel gallon equivalent (DGE)=standard cubic feet (SCF) of natural gas divided by 139), the amount of fuel provided on board the vehicle may be, for example, up to about 28 DGE, 45 DGE, 52 DGE, 60 DGE, 63 DGE, 70 DGE, 75 DGE, 80 DGE, 88 DGE, 92 DGE, 140 DGE, 100 DGE, 105 DGE, 120 DGE, 140 DGE, 160 DGE, 176 DGE, or more than 176 DGE. 
     The fuel tank  114  may have any size and/or weight. For example, the fuel tank may be larger than, smaller than, or about the same size as a 5 gallon tank, 7 gallon tank, 10 gallon tank, 15 gallon tank, 20 gallon tank, 25 gallon tank, 30 gallon tank, 40 gallon tank, 50 gallon tank, 70 gallon tank, 90 gallon tank, 110 gallon tank, 130 gallon tank, 150 gallon tanks, or 170 gallon tank. The fuel tank may weigh more than, less than, or equal to about 0.01 tons, 0.03 tons, 0.05 tons, 0.07 tons, 0.1 tons, 0.2 tons, 0.3 tons, 0.5 tons, 0.7 tons, or 1.0 tons. For example, the fuel tanks may be of cylindrical form with dimensions (radius in inches×length in inches) of, for example, 25″×39″, 25″×61″, 25″×80″, 25″×90″, 26″×80″, 26″×90″, 26″×120″, 26″×76″, 16″×80″, 21″×86″, 6″×120″, 21″×70″, 21″×86″, and one or more cylinders may be combined to achieve a predetermined total fuel capacity. 
     The fuel system  110  may be capable of containing a fuel at a predetermined pressure. For example, the fuel system  110  may be capable of containing a fuel having a pressure of less than or equal to about 10000 psig, 8000 psig, 7000 psig, 6500 psig, 6000 psig, 5500 psig, 5000 psig, 4750 psig, 4500 psig, 4250 psig, 4000 psig, 3750 psig, 3500 psig, 3250 psig, 3000 psig, 2750 psig, 2500 psig, 2000 psig, 1500 psig, 1000 psig, 500 psig, 300 psig, 100 psig, or less. Optionally, the fuel system may be structurally capable of containing a fuel having a high pressure value, such as at least the pressure values described above. 
     In embodiments requiring cooling and/or insulation, such as in LNG fuel systems, the fuel system components may be appropriately outfitted with insulation, chillers and/or other components known in the art. For example, the fuel transfer lines and the fuel tank  114  may be wound with insulation. 
     The fuel system  110  may have one or more fuel outputs. The fuel output may transfer the fuel to another part of the vehicle  100 , such as an engine. In one example, the fuel may be output to mix with air in the cylinder of an engine. The system  200  provides a novel output that can be employed in an emergency situation as discussed herein. 
     The fuel system  110  may be housed in a cover  120 , which may be mounted to the vehicle, and may serve to contain and protect the fuel tank  114  and other fuel system components. The cover  120  may be made of a variety of materials, including, but not limited to, metal or metal alloys (e.g., steel, iron, aluminum, titanium, copper, brass, nickel, silver, or any alloys or combinations thereof), composite materials (e.g., carbon fiber, fiberglass), or polymer materials. The cover  120  may be made of a single material or may comprise multiple pieces made of different materials. The fuel system  110  may be partially housed in the cover  120 . In some embodiments, one or more components of the fuel system  110  or the venting system  200  may reside outside of the cover  120 . For example, the fuel distribution system components may reside partially inside and partially outside of the cover  120 , or fully outside (e.g., within the body of the vehicle) of the cover  120 . 
     The manual venting system  200  is provided to improve safety in an emergency situation. The system  200  allows an operator to manually vent the fuel tanks  114 . The activation advantageously can be before a pressure relief device has been thermally activated. The system includes an actuator  210  located inside the cab C of the vehicle  100 . The actuator  210  is configured to cause a control valve  220  to open when the operator engages the venting system. 
     The actuator  210  can operate a cable system  230  that is routed from a location inside the cab C of the vehicle to the control valve  220  at or adjacent to the tank or tanks  114 . The cable system  230  can have a first end disposed adjacent to or in the cab C and a second end disposed adjacent to or on the tank or tanks  114 . The cable system  230  preferably includes a protective member that maintains the operability of a cable thereof. For example, a tubular body can be provided that has an inner periphery greater than the outer periphery of a cable disposed in the tubular body. A gap between the inner and outer periphery enables the cable to slide such that the control valve  220  can be actuated upon such sliding. 
     The actuator  210  can take any suitable form, for example including rigid member rotatable about an axle having the first end of the cable mounted thereto at a location eccentric to the axis of rotation of the rigid member. The rigid member can be in the form of a handle. Other mechanical actuators can be provided, such as a button that can be depressed to engage the cable or a toggle device or other mechanical device. 
     A cover can be provided over the handle to prevent inadvertent activation of the relief valve. 
     Conventionally, in the event of a fire a pressure relief device is provided that is thermally activated. Because the pressure relief device relies on heat melting or otherwise altering a structure of the valve, there is a delay in the opening of the valve. In a situation where the operator is certain that the tank needs to be vented, the manual vent system  200  allows the immediate or short delay venting of gas. Instead of waiting critical seconds or minutes for a vent to occur, the operator would engage the actuator  210  to guarantee the vent as indicated by the arrow A. In the embodiments of  FIGS. 1 and 2   a , the venting occurs from the top of a stack  240  connecting the tanks(s)  114  to a location above the vehicle. In the embodiments of  FIGS. 2 b  and 2 c    the venting occurs from the top of the cover  120  or directly from the tanks or the same level as the tanks, making the stack optional in these embodiments. 
     In one variation, the actuator  210  and/or the cable system  230  can be configured to provide a time lag between actuating the actuator and the opening of the valve  220 . In one embodiment, the actuator  210  can be thermally activated. In one embodiment, a wire that shrinks upon being heated can be provided inside the cover to cause the cable in the cable system  230  to move such that the control valve  220  opens. The thermal activation can be one that provides a much shorter lag time than a typical PRD, thus providing quicker activation than a PRD but providing needed time for an operator or those around the vehicle  100  time to get away from the vehicle. The time delay is preferably less than the lag in a conventional pressure relief device, but long enough to permit the operator or other persons near the vehicle to get to a safe radius. For example, a time lag of 10 or more seconds, of 20 or more seconds, or of 30 or more seconds can be provided. In certain embodiments a time lag of about a minute or more can be provided. 
     In one variation, the manual vent system  200  is mechanically operated and is configured to be bypassed by an emergency responder. For example, a label or other indicator can be provided on or near the cable system  230  indicating that a cable therein actuates a manual relief valve. The emergency response personnel can cut the cable system  230  and pull or release the cable therein to open the valve. This provides manual activation of the manual vent system  200  from a location outside the cab C. It is also a manual override of the system  200  that can allow venting without entering the cabin C. An emergency first responder can override the system  200  to trigger or activate the emergency valve. In one variation, the time lag component of the device is located close to the valve  220  so that even when the cable system  230  is cut the first responder is given time to evacuate the immediate area before the venting occurs. 
     In another embodiment, the manual venting system  200  is configured to provide a signal to the valve  220  when the actuator  210  is actuated. The actuator  210  can be connected to the valve  220  by a wire for communicating a manual signal to open the valve  220 . In one embodiment, the actuator  210  is a button that is electrically coupled with a controller such as an electronic control unit (ECU) of the fuel system  110 . The button can be electrically coupled by a wire to the ECU. The button can be electrically coupled by a wireless transmitter to the ECU. The button can be located in the cab of the vehicle with which the fuel system is coupled. 
     In one variation, the manual vent system  200  is electrically operated and is configured to be bypassed by an emergency responder. For example in the case of a wirelessly operated system, the first responder can have a device capable of sending a signal to open the valve directly to a controller, the ECU, or the valve  220  to cause the valve  220  to open. The wireless connection can be by any known wireless technology. The opening of the valve  220  can be immediate or on a suitable lag. In one variation, the emergency responder can specify the lag time based on how much time is needed to clear the area. 
     There have been a many situations around the world where mechanical or thermally activated PRD&#39; s do not perform as intended resulting in catastrophic detonation of cylinders. The manual venting system  200  provides a way to avoid such events. 
       FIG. 3  illustrates another embodiment of a vehicle  300  that can have a fuel system  310  and a vent system  320 . The vehicle  300  and the fuel system  310  can be similar to vehicle  100  and the fuel system  110  except as described differently below. The vent system  320  can have a primary vent actuator  324  that is disposed on or in the cab C of the vehicle  300 . The vent actuator  324  can be a button disposed within the reach of the driver as discussed above. The vent actuator  324  can operate on any principle. In the illustrated embodiment, actuating the actuator  324  causes an electrical signal to pass along an electrical wire  328  that extends from a first end coupled with the actuator  324  to a second coupled with a valve  332 . The valve  332  can be similar to the valve  220 . In either case, the valve can include a mechanism to cause a blocking structure to move aside allowing gas in the fuel system  110 ,  310  to exit the system. The mechanism can include any known structure for moving a blocking structure, such as a solenoid. Because one application of the systems described herein is to contend with an emergency situation such as a fire, the electrical wire  328  preferably is disposed in a fire resistant structure. The electrical wire  328  can include or be enclosed in an insulator that is rated to a temperature higher than a typical vehicle fire such that a fire will not destroy the electrical wire  328 . 
     In some embodiments, the vent system  320  includes a secondary actuator  340  disposed adjacent to the valve. The secondary actuator  340  can be a mechanical actuator. A mechanical actuator is advantageous in that if the electrical wire  328  is damaged for any reason, the mechanical actuator can open the valve  332 . A mechanical actuator can include a lever, an over-center mechanism, a cam or other direct action mechanism, that pushes a blocking structure of the valve  332  to an open position. 
     Although these inventions have been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present inventions extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the inventions and obvious modifications and equivalents thereof. In addition, while several variations of the inventions have been shown and described in detail, other modifications, which are within the scope of these inventions, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combination or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of at least some of the present inventions herein disclosed should not be limited by the particular disclosed embodiments described above.