Abstract:
A unitary fuel system module comprising one or more fuel cylinders mounted to a frame as a module, preferably through neck-mounts, and having fueling lines for connecting the fuel cylinders to the vehicle. The frame is fitted with a latching mechanism that is readily actuated for alternately securing the frame to the fuel supply envelope in the vehicle or releasing the frame for removal of the fuel module as a unitary structure. Preferably, the frame is fitted with wheels or slides to enable sliding the module in and out of the envelope. In operation, as required return a vehicle to operation, a faulty module can be replaced with a replacement module, which is slid into the envelope where it is secured and-the fueling lines are re-connected to the vehicle.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to the field of vehicular fuel storage and supply systems and more particularly to replaceable fuel systems for alternative fuels such as compressed natural gas (CNG), hydrogen, and liquefied natural gas (LNG).  
         BACKGROUND OF THE INVENTION  
         [0002]    Typically, on-board vehicular fuel supply systems comprise one or more fuel tanks integrated into the chassis of a vehicle. Installation of the fuel system is a part of the vehicle&#39;s basic construction and is typically performed in assembly-line fashion at the factory.  
           [0003]    Fuel systems such as described in U.S. Pat. No. 5,794,979 to Kasuga et al. are designed for alternative fuels such as CNG or LNG where a plurality of compressed pressurized fuel cylinders are mounted in a vehicle. A tank supporting frame, installed complete with the fuel tanks and associated pipes and seals, is preferably installed through a rear window opening, during initial manufacture of the vehicle. The frame, following insertion into the fuel storage envelope in the vehicle, is subsequently bolted to the car body and the ends of the pipes connected to the ends of the fuel lines on the car body. Once installed in this fashion, the fuel system becomes an integral part of the vehicle body and cannot be readily removed for inspection, repair or replacement.  
           [0004]    Malfunction in any part of the system results in costly repair and significant down-time as the vehicle must be removed from the road. Costs escalate with increasing time to disassemble portions of the vehicle to gain access to the system, perform repairs and reassemble the vehicle.  
           [0005]    U.S. Pat. No. 5,997,040 to Fukagawa et al. teaches a modularized and compact fuel system comprising a support frame bolted to the car-body side supporting frame, a single fuel cylinder secured to the support frame using belly straps and a joint box for connection of the fuel and fill lines from the tank to the lines of the vehicle. The frame taught in Fukagawa is not readily adapted to secure more than one fuel cylinder nor is there any indication that fuel lines from a plurality of fuel cylinders could be integrated into the joint box provided. Fukagawa teaches additional side frame components being bolted first at each side of the car body prior to installation of the module. The fuel tank attached to the remaining portion of the frame is then inserted into the car body through a rear door and moved rearward between the wheel housings to align with the side frame component. Once aligned, the module is bolted into place. If maintenance is required, the reverse steps are performed including un-bolting all the fasteners for lifting the module free of the vehicle. Fukagawa avoids multiple vessels so as to ensure a compact module for ease of installation. A larger vessel or a plurality of vessels are not contemplated.  
           [0006]    Where a plurality of vessels is required to increase the capacity of the system, the single vessel system of Fukagawa is no longer applicable.  
           [0007]    Clearly there is a need for a lightweight fuel system comprising a plurality of pressurized fuel cylinders held together in a unitary structure complete with piping and valves that can be safely secured to the body of a vehicle when in use, but be readily removable for service. Securing means that can be readily released, combined with removable piping connections would allow the entire fuel system to be removed from its permitted dimensional fuel storage envelope in the vehicle for inspection or servicing. Further, a modular system could be replaced even on site, as a single module, should it malfunction. Swapping of a replacement module for the faulty module permits rapid repairs and also avoids unnecessary delays.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention overcomes the prior art requirement for labor intensive and costly servicing, inspection or replacement of a fuel system. A lightweight, unitary fuel system module is provided that can be quickly and removably secured to a vehicle body. The module is easily unlatched from the body and, with minimal detachment of piping connections, can be partially or completely removed, as a complete module, from the vehicle for inspection, repair or reinsertion. Should the module require unknown or extensive repair or component replacement, the entire used module can be replaced by a second replacement module to minimize on-road time losses.  
           [0009]    In a broad aspect of the invention, a modular fuel system is provided for a vehicle having fuel lines and a fuel storage envelope, the fuel system comprising:  
           [0010]    one or more pressurized fuel cylinders;  
           [0011]    a frame in which the one or more fuel cylinders are mounted to form a replaceable module; and  
           [0012]    a latching mechanism attached to the frame and adapted for cooperating with anchors in the envelope for releasably securing the frame within the vehicular envelope and operable between a first secured position and a second released position.  
           [0013]    Such replaceable modules are self supporting during removal and replacement steps. Preferably, each fuel cylinder has a longitudinal axis and opposing neck ends, the opposing neck ends of each of the one or more fuel cylinders being neck-mounted to the frame. The fuel cylinders, associated instrumentation and tubing are secured to the frame for insertion into the vehicle as a unitary module.  
           [0014]    In a preferred embodiment of the invention, the fuel cylinders and associated tubing are housed in a mounting frame comprising at least two end brackets. The brackets are lightweight and designed to permit neck-mounting of each fuel cylinder at opposing neck ends. The frame is secured to the structure of a fuel storage envelope within the vehicle using a releasable latching mechanism capable of safely securing the frame under crash loading. Further, the frame is fitted with means to allow easy removal of-the-system-as a module, such as roller wheels or cooperating Teflon slides.  
           [0015]    Preferably, the fuel cylinders are lightweight fiber reinforced, aluminum-lined fuel cylinders having opposing neck-ends, capable of storing pressurized fuel gas such as hydrogen. Instrumentation associated with delivery and monitoring of fuel is provided. Three lines of pressure tubing are typically used for connecting the fuel cylinders to the vehicle; a filling line, a fuel line and a venting line. Each line is housed within a mounting frame for connection to the fuel cylinders, in parallel. The fueling lines converge at a periphery of the frame for ease of connection to the vehicle. Removable fittings join the three lines to corresponding lines on the vehicle body. More preferably, the frame further comprises crossbeams for additional structural rigidity and for attachment of the latching mechanism to the underside of the frame. With pressurized fuel cylinders, the neck-mounting attachments are preferably adapted to permit some longitudinal expansion at least atone neck-mount.  
           [0016]    In another aspect of the invention, a method for removal and replacement of a used module of the present invention from a vehicle fuel storage envelope is provided, the method comprising the steps of:  
           [0017]    providing at least two modules, a used module and a replacement module, each module having one or more fuel cylinders mounted to a frame, the frame having a latching mechanism for securing the mounting frame to the vehicular envelope;  
           [0018]    disconnecting means for fluidly connecting the pressurized fuel cylinders with fuel lines in the vehicle;  
           [0019]    actuating the latching mechanism of the used module from a first secured position to a second released position; then sequentially  
           [0020]    removing the used module from the vehicle&#39;s envelope;  
           [0021]    inserting a replacement module into the vehicle&#39;s envelope; and then  
           [0022]    actuating the latching mechanism of the replacement module for securing the mounting frame to the vehicle from a second released position to a first secured position; and  
           [0023]    reconnecting the means for fluidly connecting the pressurized fuel cylinders with the fuel lines in the vehicle.  
           [0024]    The method is particularly convenient when two or more fuel cylinders are involved in the module.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    [0025]FIG. 1 is a perspective view of the fuel system module of the present invention;  
         [0026]    [0026]FIG. 2 is a perspective view of the fuel system module of FIG. 1 installed in a rear fuel storage envelope in a vehicle and having a cut away in one fuel cylinder to show an anchoring mechanism of the present invention securing the module into the envelope;  
         [0027]    [0027]FIG. 3 is a perspective view of the fuel system module of FIG. 1 partially installed in an underbody fuel storage envelope in the side of a vehicle;  
         [0028]    [0028]FIG. 4 is a perspective view of the frame of the fuel system module of FIG. 1 showing the brackets, cross-beams; anchoring mechanism and neck-mounting attachments;  
         [0029]    [0029]FIG. 5 is a perspective view of the frame of the fuel system module according to FIG. 4 without the neck-mounting attachments;  
         [0030]    [0030]FIG. 6 is a perspective view of the underside of the fuel system module according to FIG. 1 showing the anchoring mechanism in a secured position and the wheels retracted;  
         [0031]    [0031]FIG. 7 is a front view of the underside of the fuel system module according to FIG. 1 showing the anchoring mechanism; and  
         [0032]    [0032]FIG. 8 is a schematic illustrating the valving and tubing connections of the pressurized fuel cylinders using an external pressure regulator.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0033]    Having reference to FIGS.  1 - 3 , a modular fuel system  10  of the present invention is shown. A plurality of pressurized fuel cylinders  20  are attached to a frame  30  for insertion, as a module  10 , into a fuel storage envelope  40  in a vehicle  100 . Further, fueling tubing or lines  50  associated with filling and venting the fuel cylinders  20 , as well as fueling the vehicle  100 , are provided. As shown in FIGS. 2 and 3, the frame  30  is secured to the structure of the fuel storage envelope  40 , using a releasable latching mechanism  60 .  
         [0034]    The frame, as shown in FIGS.  4 - 5 , comprises first and second end brackets  31 ,  32  spaced and secured to the fuel cylinders  20 . Preferably, one or more cross beams  33  extend between the brackets  31 , 32  in part to provide additional structural rigidity and to provide additional points of attachment as necessary. One or more sets of neck-mounting attachments  34   a,    34   b  are bolted to the frame brackets  31 , 32  for neck-mounting opposing neck ends  21 , 22  of each pressurized fuel cylinder  20 .  
         [0035]    Alternatively, fuel cylinders  20  can be mounted to the crossbeams  33  of the frame  30 , using conventional belly straps (not shown).  
         [0036]    Preferably, the pressurized fuel cylinders  20  are fixed at threaded neck-mounting attachments  34   a  at one or either end bracket  31 , 32  of the frame  30  by a fixed or threaded neck end  21 , 22  into which a valve assembly  55  and fueling lines  50  are fit (FIG. 7). The neck-mounting attachments  34   b  at the opposing ends of the fuel cylinders  22 , 21  are slidably fit, such as with plastic bushings (not shown), which support the fuel cylinder&#39;s neck end  22  yet still allows for lineal expansion of the pressurized fuel cylinders  20  such as under fill/empty pressures cycles.  
         [0037]    In one embodiment of the invention, as shown in FIGS.  4 - 7 , the latching mechanism  60  comprises one or more anchoring mechanisms  60   a  fixed to the frame  30 , such as to the cross-beams  33 . Each anchoring mechanism  60   a  comprises a support bracket  61 , having a first hook  62  at a first end  63  and a second hook  64  at a second end  65  of the support bracket  61 . Each hook  62 , 64  is pivotally attached to the support bracket  61  and can be actuated from an open, released position to a closed, secured position. The hooks  62 , 64  happen to be oriented with open sides  66  facing in opposing directions (shown facing away from each other) for co-operating with corresponding and complementary anchors  74  (as seen in FIG. 2) in the envelope  40 .  
         [0038]    Each hook  62 , 64  is pivotally connected to the support bracket  61  and to an actuation arm  67  at the arm&#39;s first  68  or second end  69  respectively. For contra-rotation of the opposing hooks, the actuation arm  67  extends from a top  70  of the first hook  62  to a bottom  71  of the second hook  64 . The actuation arm  67  is further connected to a handle  72  at the first end  63 . As the handle  72  is depressed, the adjacent first hook  62  is caused to pivot about its attachment  73  to the support bracket  61 , the open side  66  pivoting downward, to a released position. At the same time, the second hook  64  is caused to pivot downward, also to a released position. When the handle  72  is lifted, the hooks  62 , 64  are caused to pivot away from one another to a secured position in engagement with anchors  74  formed in the envelope  40  (FIG. 2.).  
         [0039]    Optionally, the handle  72  is positioned at a periphery of the frame  30  or at a location remote from the module  10  to provide easy access for actuating the latching mechanisms  60 . This may be of particular importance in vehicular envelopes  40  that are severely space-restricted where access to the underside of the frame  30  is limited.  
         [0040]    As shown in FIG. 2, loop-like anchors  74  are provided in the structure of the fuel storage envelope  40 , typically at a base  41  of the envelope  40 , through which the hooks  62 , 64  of the anchoring system  60   a  extend when in the secured position. In this secured position, the frame  30  is safely secured to the vehicle  100 . Finite element analysis of the module  10  confirms structural performance under regulatory requirements such loading with 25 g in planes parallel and perpendicular to the pressurized fuel cylinder&#39;s axis and 5 g in the vertical plane. One form of the latching mechanisms of the type herein disclosed are typically found in the automobile industry for use in securing rear bench seats to the vehicular frame.  
         [0041]    As shown in FIGS.  7 - 8 , typical fueling lines  50  comprise a fill line  51 , a fuel line  52  and a venting line  53  which are connected to corresponding lines (not shown) in the vehicle  100 . The fueling lines  50  are carried on or secured to the frame  30  connecting two or more fuel cylinders  20  in parallel. Instrumentation or electrical control lines (not shown), as required, are also carried within the frame  30 . Further, the fueling lines  50  converge at a periphery of the frame  30 , and the envelope  40 , for ease of connection to the corresponding lines in the vehicle  100 . Connection is accomplished using releasable fittings between the corresponding lines.  
         [0042]    Turning to FIG. 8, the fill line  51  allows the fuel cylinder  20  to be filled with compressed gas from an outside source. Check valves  54  are installed in each fuel cylinder&#39;s valve assembly  55 . A fuel filter  56  is installed between the filling receptacle (not shown) and the valve assembly  55  to prevent contamination entering the system. Fuel from the fuel cylinders  20  is directed through one ore more pressure regulators  81 . A pressure switch  57  (P 1 ), used to shut off the system in case of over-pressure and a manual valve  58  used for defueling, are also connected to the fuel line  52 . The venting line  53  is required for gas release from temperature and pressure-activated relief devices (PRD&#39;s)  80 .  
         [0043]    Further as part of a typical instrumentation package, the module  10  is provided with at least one temperature sensor T and one pressure sensor P 2  which indicates the pressure inside the fuel cylinder  20  when an electromagnetic or solenoid shut-off valve  59  is opened. As shown in FIGS. 7 and 8, a pressure regulator  81  can be connected externally to the fuel line  52 .  
         [0044]    Typical parameters for a module  10  as described include 250 or 350 bar (gauge) pressurized fuel cylinders  20  and pressure regulators having transducers in the range of nominal 0-450 bar (gauge).  
         [0045]    Preferably, the frame  30  is spaced from the structure of the fuel storage envelope  40  by anti-vibration pads  90  which are compressed when the latching mechanism  60  is actuated.  
         [0046]    More preferably, the frame  30  is further provided with means  91  such as wheels or co-operating Teflon slides which are supported by the envelope  40 , to assist in removing and inserting the module  10  into and out of the fuel storage envelope  40 .  
         [0047]    In one embodiment of the invention, as shown in FIGS.  4 - 7 , at least one wheel  92  is attached to the anchoring mechanism  60   a  and pivotally actuated with the hooks  61 ,  63 . Actuation of the anchoring mechanism  60   a  to the released position causes the hooks  61 , 63  to be released and the wheels  92  to pivot to a downward position where they contact the structure of the fuel storage envelope  40  and raise the frame  30  slightly so as to assist in removing or inserting the module  10  into the fuel storage envelope  40 . Further, eyelets  101  are provided on each bracket  31 ,  32  to assist in lifting the module once it has been removed from the vehicle.  
         [0048]    In use, a used module  10  is removed for inspection or, if required, is rapidly replaced by a substantially identical replacement module  10 . The fittings, which connect the fueling lines  50  on the fuel cylinders  20  to the fuel lines in the vehicle  100 , are typically disconnected first. Removal of the used module  10  is accomplished by actuating the anchoring mechanism  60   a  on the frame  30  to a released position to release the frame  30  from its attachment to the anchors  74  in the structure of the fuel storage envelope  40 . While it is not essential to release the frame or disconnect the fueling lines in any particular order, one does avoid disruption of the fuel lines  50  if they are disconnected before releasing the used module. The used module  10  can then be removed from the fuel storage envelope  40  as a unitary structure and either repaired or replaced with a replacement module  10  in the reverse order.  
         [0049]    Optionally, in embodiments wherein the handle  72  of the anchoring mechanism  60   a  is appropriately situated, actuation of the anchoring mechanism  60   a , is performed at a location at the periphery of the frame  30  or otherwise remote from the module  10 , particularly in envelopes  40  that are severely space-restricted and where access to the anchoring mechanism is difficult.