Abstract:
An automotive vehicle includes a vehicle body and at least one reservoir containing a fire suppressant agent. A distribution system receives the fire suppression agent from the reservoir and conducts the agent to at least one location about the vehicle&#39;s body in response to the determination by a sensor system and controller that the vehicle has been subjected to a significant impact. The reservoir includes a discharge port which is positioned in part by a tensile member extending through the reservoir to an anchor incorporated in an external wall section of the reservoir.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 10/907,134, filed Mar. 22, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an automotive vehicle having an onboard apparatus for suppressing a vehicle fire.  
         [0004]     2. Disclosure Information  
         [0005]     Police vehicles are subject to increased exposure to collisions, particularly high-speed rear-end collisions, arising from the need for police officers to stop on the shoulders, or even in the traffic lanes, of busy highways. Unfortunately, other motorists are known to collide with police vehicles employed in this manner. These accidents can compromise the fuel system on any vehicle and may cause fires. The present system is designed to suppress the spread of, or potentially, to extinguish such a fire. U.S. Pat. No. 5,590,718 discloses an anti-fire system for vehicles in which a number of fixed nozzles are furnished with a fire extinguishing agent in response to an impact sensor. The system of the &#39;718 patent suffers from a problem in that the fixed nozzles are not suited to the delivery of the extinguishing agent at ground level. Also, the &#39;718 patent uses a valving system which could become clogged and therefore inoperable. U.S. Pat. No. 5,762,145 discloses a fuel tank fire protection device including a powdered extinguishing agent panel attached to the fuel tank. In general, powder delivery systems are designed to prevent ignition of fires and are deployed upon impact. As a result, the powder may not be able to follow the post-impact movement of the struck vehicle and may not be able to prevent the delayed ignition or re-ignition of a fire.  
         [0006]     The present fire suppression system provides significant advantages, as compared with prior art vehicular fire suppression systems.  
       SUMMARY OF THE INVENTION  
       [0007]     According to one aspect of the present invention, an onboard fire suppression system includes at least one fiber reinforced composite reservoir containing a fire suppression agent. A propellant, operatively associated with the reservoir, expels the suppression agent from the reservoir. A propellant may be located either inside the reservoir or externally thereto.  
         [0008]     A discharge port extends through a first wall section of the reservoir. A distribution system receives fire suppression agent expelled from the reservoir and distributes the depressant agent in at least one location external to a vehicle. The distribution system is connected to the discharge port. A retaining system, located within the reservoir, maintains the discharge port in registry with the first wall section. The retaining system includes an anchor incorporated in a second wall section opposing the first wall section, and a tensile member extending through the interior of the reservoir, with the tensile member being attached to the anchor and to the discharge port.  
         [0009]     In a first embodiment, the discharge port, the anchor, and the tensile member all comprise metallic members. These metallic members may be fabricated from either ferrous or non-ferrous metals. The tensile member is preferably pre-tensioned. The tensile member may be configured as a number of separate cable elements, with each of the elements having a first end attached to the anchor and a second end attached to the discharge port.  
         [0010]     According to another aspect of the present invention, the reservoir may include a fill port extending through a third wall section of the reservoir. A secondary anchor incorporated in a fourth wall section opposing the third wall section, and an added tensile member extending through the interior of the reservoir maintain the fill port in proper registry with the third wall section of the reservoir.  
         [0011]     According to another aspect of the present invention, a discharge port includes a flanged inner portion and a threaded outer portion having a threaded fastener attached thereto to serve as an abutment facing the outer surface of the first wall section, through which the discharge port extends.  
         [0012]     According to another aspect of the present invention, a method for constructing an internally reinforced reservoir for an onboard fire suppression system includes forming a reservoir body, including at least one discharge port located in a first wall section of the reservoir body, followed by extending a tensile member from the discharge port to a second wall section of the reservoir body. Then, the tensile member is tensioned and affixed to the second wall section so that the tension member remains in tension during standby operation of the reservoir. As used herein, the term “standby operation” means operation during any period of time in which the onboard fire suppression system is available for service, but waiting for the signal from a controller to activate the propellant, so as to cause discharge of the suppressant agent onto a location in or about a vehicle, including at least one external location.  
         [0013]     Other advantages, as well as features of the present invention will become apparent to the reader of this specification. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a ghost perspective view of an automotive vehicle having a fire suppression system according to the present invention.  
         [0015]      FIG. 2  is an exploded perspective view of a portion of a fire suppression system according to the present invention.  
         [0016]      FIG. 3  is a perspective view of a control module used with a system according to the present invention.  
         [0017]      FIG. 4  is a perspective view of a manually activatable switch used with a fire suppression system according to the present invention.  
         [0018]      FIG. 5  illustrates a portion of a wiring harness used with the present system.  
         [0019]      FIG. 6  is a flowchart showing a portion of the logic used to control a system according to the present invention.  
         [0020]      FIG. 7  is a cutaway perspective view of a fire suppression agent reservoir according to one aspect of the present invention.  
         [0021]      FIG. 8  is a perspective view of a variable geometry fire suppression agent nozzle according to one aspect of the present invention.  
         [0022]      FIG. 9  is a block diagram of a fire suppression system and with additional components for occupant restraint according to one aspect of the present invention.  
         [0023]      FIG. 10  is a perspective view of a vehicle having a fire suppression system with an internally reinforced reservoir according to one aspect of the present invention.  
         [0024]      FIG. 11  is a cutaway view of a suppression agent reservoir according to one aspect of the present invention.  
         [0025]      FIG. 12  is a cutaway perspective view of a reservoir having an external propellant according to one aspect of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     As shown in  FIG. 1 , vehicle  10  has a passenger airbag restraint  48  and a driver&#39;s airbag restraint  50  mounted adjacent steering wheel  52 . A fire suppression system includes controller  66  which is mounted upon floor pan  68  of vehicle  10 , and reservoirs  18  which are mounted under floor pan  68  in the so-called kick-up area adjoining the rear axle of vehicle  10 . Those skilled in the art will appreciate in view of this disclosure that additional passenger restraint devices, such as seat belt pretensioners and side airbags, may be installed in a vehicle and controlled at least in part by, or in conjunction with, controller  66 .  
         [0027]      FIG. 1  shows not only reservoirs  18  but also a portion of right and left side fire suppression conduits  28 , as well as fixed geometry nozzles  30  and variable geometry nozzles  36 . As seen in  FIG. 1 , variable geometry nozzles  36  project downwardly to allow fire suppression agent to be expelled from reservoirs  18  and placed at a low angle to the ground surface the vehicle is operating upon. This mode of operation is possible because variable geometry nozzles  36  are, as shown in  FIG. 2 , telescopingly extensible. This telescoping feature, which is shown in greater detail in  FIG. 8 , is produced by a sliding spray head,  40 , which is slidingly engaged with conduit  28  such that gas pressure within conduit  28  forces spray head  40  downwardly into its extended position, causing fire suppression agent  22  to be discharged through a number of holes  42  formed in spray head  40 . As shown in  FIG. 2 , at least two variable geometry nozzles  36  may be employed with single reservoir  18 , along with at least two fixed nozzles  30  which are spray bars each having a number of orifices  34 . While in their normally closed state, variable geometry nozzles  36  are liquid-tight by virtue of seals  46 , which are interposed between an end of each of spray heads  40  and the corresponding ends of conduits  28 . In a preferred embodiment, seals  46  comprise elastomeric boots attached to an outer surface of conduit  28 . Seals  46  are simply sheared by the deploying spray head  40  when the present system is discharged. Fixed nozzles  30  are also rendered liquid-tight by covers  44 , which are simply blown off when the present system is discharged. The sealing of nozzles  30  and  36  is important, because this prevents the ingress of road splash, which could block the system in sub-freezing weather or cause corrosion or blockage due to mud or other foreign matter.  
         [0028]     Additional details of reservoir  18  are shown in  FIG. 7 . Tank  90  contains approximately 1.5 L of fire suppression agent  22 , and a propellant  92 . Propellant  92  includes two squibs (not shown) which are activated simultaneously by controller  66  via lines  91  so as to release a large amount of gas, forcing fire suppressant agent  22  from tank  90  and into distribution system  26 , including conduit  28  and the various fixed and variable geometry nozzles. A preferred propellant, marketed by Primex Aerospace Company as model FS01-40, is a mixture including aminotetrazole, strontium nitrate, and magnesium carbonate. This is described in U.S. Pat. No. 6,702,033, which is hereby incorporated by reference into this specification.  
         [0029]     Those skilled in the art will appreciate in view of this disclosure that other types of propellants could be used in the present system, such as compressed gas canisters and other types of pyrotechnic and chemical devices capable of creating a gas pressure force in a vanishingly small amount of time. Such propellants may be mounted either within a reservoir with the fire suppressant agent, or externally thereto. Moreover, fire suppressant agent  22 , which preferably includes a water-based solution with hydrocarbon surfactants, fluorosurfactants, and organic and inorganic salts sold under the trade name LVS Wet Chemical Agent® by Ansul Incorporated, could comprise other types of agents such as powders or other liquids, or yet other agents known to those skilled in the art and suggested by this disclosure. If two reservoirs  18  are employed with a vehicle, as is shown in  FIG. 1 , all four squibs will be deployed simultaneously.  
         [0030]      FIG. 4  shows manually activatable switch  54  for use with the present system. As shown in  FIG. 1 , switch  54  may be advantageously located on the headliner of vehicle  10  between the sun visors, or at any other convenient position. To use this switch  54 , hinged clear cover  56  is first opened by pressing on cover  56 . Thereafter, the fire suppression system may be triggered by manually pressing pushbutton  58 . If the vehicle occupants are not disposed to release cover  56 , the system may be triggered by merely sharply depressing cover  56 , thereby closing contacts (not shown) contained within platform  60 .  
         [0031]     Because the present system is intended for use when the vehicle has received a severe impact, controller  66 , which is shown in  FIG. 3 , contains a redundant power reserve or supply, which allows operation of the fire suppression system for about nine seconds, even if controller  66  becomes isolated from the vehicle&#39;s electrical power supply. Wiring harness  80 , as shown in  FIG. 5 , is armored, and has a para-aramid fiber inner sheath,  82 , of about 2 mm in thickness, which helps to shield the conductors within harness  80  from abrasion and cutting during a vehicle impact event. This para-aramid fiber is sold under the trade name KEVLAR® by the DuPont Company. This armoring helps to assure that communication between controller  66  and reservoirs  18  remains in effect during an impact event. Post-impact communications are further aided by redundancy in the control system. Specifically, four independent sets of primary conductors,  79   a - d , extend from controller  66  to reservoirs  18  protected by sheath  82 . Moreover, an H-conductor, shown at  81  in  FIG. 5 , extends between reservoirs  18 . Thus, if one or both of the primary conductors  79   a - b , or  79   c - d , extending to one of reservoirs  18  should become severed, H-conductor  81  will be available to carry the initiation signal from the undamaged lines to both of reservoirs  18 .  
         [0032]     As noted above, an important feature of the present invention resides in the fact that the control parameters include not only vehicle impact, as measured by an accelerometer such as that shown at  70  in  FIG. 9 , but also vehicle speed, as measured by means of speed sensors  74 , also shown in  FIG. 9 . Speed sensors  74  may advantageously be existing sensors used with an anti-lock braking system or vehicle stability system. Alternatively, speed sensors  74  could comprise a global positioning sensor or a radar or optically based ground-sensing system. Accelerometer  70 , as noted above, could be used with a conventional occupant restraint airbag system, thereby maximizing use of existing systems within the vehicle. Advantageously, accelerometer  70  may be an amalgam of two or more accelerometers having differing sensing ranges. Such arrangements are known to those skilled in the art and suggested by this disclosure. At least a portion of the various sensors could either be integrated in controller  66  or distributed about vehicle  10 .  
         [0033]      FIG. 6  shows a sequence which is used according to one aspect of the present invention for activating a release of fire suppressant agent.  
         [0034]     Beginning at block  100 , controller  66  performs various diagnostics on the present system, which are similar to the diagnostics currently employed with supplemental restraint systems. For example, various sensor values and system resistances will be evaluated on a continuous basis. Controller  66  periodically moves to block  102 , wherein the control algorithm will be shifted from a standby mode to an awake mode in the event that a vehicle acceleration, or, in other words, an impact, having a magnitude in excess of a relatively low threshold is sensed by accelerometer  70 . Also, at block  102  a backup timer will be started. If the algorithm is awakened at block  102 , controller  66  disables manually activatable switch  54  at block  104  for a predetermined amount of time, say 150 milliseconds. This serves to prevent switch  54  from inadvertently causing an out-of-sequence release of fire suppression agent. Note that at block  104 , a decision has not yet been made to deploy fire suppression agent  22  as a result of a significant impact.  
         [0035]     At block  106 , controller  66  uses output from accelerometer  70  to determine whether there has been an impact upon vehicle  10  having a severity in excess of a predetermined threshold impact value. Such an impact may be termed a significant, or “trigger”, impact. If an impact is less severe than a trigger impact, the answer at block  106  is “no”, and controller  66  will move to block  105 , wherein an inquiry is made regarding the continuing nature of the impact event. If the event has ended, the routine moves to block  100  and continues with the diagnostics. If the event is proceeding, the answer at block  105  is “yes”, and the routine loops to block  106 .  
         [0036]     If a significant impact is sensed by the sensor system including accelerometer  70  and controller  66 , the answer at block  106  will be “yes.” If such is the case, controller  66  moves to block  108  wherein the status of a backup timer is checked. This timer was started at block  102 .  
         [0037]     Once the timer within controller  66  has counted up to a predetermined, calibratable time on the order of, for example, 5-6 seconds, controller  66  will cause propellant  92  to initiate delivery of fire suppressant agent  22 , provided the agent was not released earlier. Propellant  92  is activated by firing an electrical squib so as to initiate combustion of a pyrotechnic charge. Alternatively, a squib may be used to pierce, or otherwise breach, a pressure vessel. Those skilled in the art will appreciate in view of this disclosure that several additional means are available for generating the gas required to expel fire suppressant agent  22  from tank  90 . Such detail is beyond the scope of this invention. An important redundancy is supplied by having two squibs located within each of tanks  90 . All four squibs are energized simultaneously.  
         [0038]     The velocity of the vehicle  10  is measured at block  110  using speed sensors  74 , and compared with a low velocity threshold. In essence, controller  66  processes the signals from the various wheel speed sensors  74  by entering the greatest absolute value of the several wheel speeds into a register. This register contains both a weighted count of the number of samples below a threshold and a count of the number of samples above the threshold. When the register value crosses a threshold value, the answer at block  110  becomes “yes.” In general, the present inventors have determined that it is desirable to deploy fire suppression agent  22  prior to the vehicle coming to a stop. For example, fire suppression agent  22  could be dispersed when the vehicle slows below about 15 kph.  
         [0039]     At block  112 , controller  66  enters a measured vehicle acceleration value into a second register. Thereafter, once the acceleration register value decays below a predetermined low g threshold, the answer becomes “yes” at block  112 , and the routine moves to block  114  and releases fire suppressant agent  22 . In essence, a sensor fusion method combines all available sensor information to verify that the vehicle is approaching a halt. The routine ends at block  116 . Because the present fire suppression system uses all of the available fire suppression agent  22  in a single deployment, the system cannot be redeployed without replacing at least reservoirs  18 .  
         [0040]      FIG. 6  does not include the activation of occupant restraints  48  and  50 , it being understood that known control sequences, having much different timing constraints, may be employed for this purpose. In point of contrast, the low velocity threshold allows the present system to deliver the fire suppression agent while the vehicle is still moving, albeit at a very low velocity. This prevents the rear wheels of the vehicle from shadowing, or blocking dispersion of fire suppressant agent  22 . Also, in many cases, a vehicular fire may not become well-established until the vehicle comes to a halt.  
         [0041]     As shown in  FIG. 10 , vehicle  200  has a controller  204  which operates to discharge suppression agent  216  contained within reservoirs  208  ( FIG. 11 ), through distribution system  220 .  
         [0042]      FIG. 11  shows a fiber-reinforced composite reservoir  208  having a first wall section,  212 , through which a discharge port,  224 , extends. Discharge port  224  has a generally tubular body,  228 , defining a passage,  230 . Generally tubular body  228  also has an internal flange,  232 , which abuts an inner surface of first wall section  210 . A threaded fastener,  236 , is spun down upon threads  234  formed on an external tubular surface of discharge port  224 , so as to provide an abutment for applying the pre-tensioning force provided by cable elements  240 . Cable elements  240  maintain discharge port  224  in registry with first wall section  210 . As further shown in  FIG. 11 , cable elements  240  are tensile members which extend through the interior of reservoir  208  from first wall section  210  through second wall section  214 . Cable elements  240  also extend through anchor  218 , which is placed on an exterior surface of second wall section  214 . Each of cable elements  240  has a first end attached to discharge port  224 , and a second end attached to slugs  244  which are crimped upon cables  240 . Slugs  244  keep cable elements  240  from becoming slack during the useful life of reservoir  208 .  
         [0043]     According to another aspect of the present invention, a method for constructing an internally reinforced reservoir for an onboard fire suppression system includes forming reservoir body  208  and extending tensile members  240  from discharge port  224  to second wall section  214 , followed by tensioning of tensile members, in this case elements  240 , so that cable elements  240  remain in tension during standby operation of reservoir  208 .  
         [0044]     Discharge port  24  also includes a burst disk  226 , which prevents discharge of suppressant agent from reservoir  208  before a predetermined minimum threshold pressure has been released upon firing of propellant  212 .  
         [0045]     According to another aspect of the present invention, reservoir  208  may optionally include a fill port, having an internal flange,  262 , an external threaded fastener  266 , and a fill plug  264 . Cable elements  270  extend from fill port  260 , which is located in third wall section  250  of reservoir  208 , through anchor  272 , which is located on fourth wall  254  of reservoir  208 . Slugs  276  maintain cable elements  270  in their standby position.  
         [0046]     Propellant  212  may be optionally replaced by propellant  282  which is located externally of reservoir  208  and which may include a cold gas propellant or other type of propellant, with the gas discharge being controlled by controller  204  and control valve  286 .  
         [0047]     According to another aspect of the present invention, cable elements  240 , discharge port  224 , and anchor  218  may be formed as non-metallic members or metallic members. If metallic, these components may be formed from ferrous metals or non-ferrous metals. Those skilled in the art will appreciate in view of this disclosure that various types of metallic and non-metallic and composite materials may be used for the construction of various components such as discharge port  224 , cable elements  240 , and anchor  218 . Such materials may include combinations of metallic and non-metallic components.  
         [0048]     Although the present invention has been described in connection with particular embodiments thereof, it is to be understood that various modifications, alterations, and adaptations may be made by those skilled in the art without departing from the spirit and scope of the invention set forth in the following claims.