1. Field of the Invention
The present invention relates to an automotive vehicle having an onboard apparatus for suppressing a vehicle fire.
2. Disclosure Information
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 '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 '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.
The present fire suppression system provides significant advantages, as compared with prior art vehicular fire suppression systems.
According to an aspect of the present invention, an onboard fire suppression system includes at least one reservoir containing a fire suppression agent, and a propellant, operatively associated with the reservoir, for expelling the fire suppression agent from the reservoir. A distribution system receives fire suppression agent expelled from the reservoir and distributes the suppressant agent in at least one location external to a vehicle. The reservoir contains an open-celled structural foam which is bonded to at least a portion of the interior surface of the reservoir.
It is an advantage of the present fire suppression system reservoir that structural foam reinforcement offers increased reservoir strength, particularly with reservoirs which are neither spherical nor cylindrical. This permits fire suppression system reservoirs to be packaged in the irregularly shaped spaces often found in vehicles.
Other advantages, as well as features of the present invention will become apparent to the reader of this specification.
As shown in
Additional details of reservoir 18 are shown in
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
Because the present system is intended for use when the vehicle has received a severe impact, controller 66, which is shown in
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
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.
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.
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.
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.
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.
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.
As shown in
Depressant agent discharged from reservoirs 208 enters distribution system 216 which distributes suppressant agent in at least one location external to vehicle 200.
As shown in
In a preferred embodiment, reservoir 208 is fabricated from a fiber-reinforced resin composite, with structural foam 220 being formed as a metallic foam. Such foams may be formulated as an alloy of aluminum, or aluminum and nickel, or aluminum, nickel and chromium. Alternatively, foam 220 may be a plastic foam such as a microcellular carbon graphitic fiber reinforced foam. Although foam 220 need not be bonded to the interior surface of reservoir 208, such bonding will greatly increase the strength of reservoir 208 and this is particularly important in the case where reservoir 208 is constructed as a composite pressure vessel. Known vessels are usually cylindrical or round because such shapes are volumetrically efficient and allow for efficient use of externally wound fiber reinforcements. However, available package space or volume within a vehicle frequently does not allow the use of a cylindrical or round configuration. Such is the case with the present system, because the fire suppression equipment is mounted under the vehicle's floor in the so-called “kick up” area of a vehicle. The irregularly shaped reservoirs 208 are not easily constructed of wound fibers because of the lack of geometrical symmetry. As a result, the use of foam 220 having a low density but having a high tensile strength and high storage capacity because of its open-cell reticulated construction, greatly increases strength of reservoirs 208 without materially decreasing the suppressant agent storage capacity. Because structural foam 220 provides a corrosion resistant method for increasing the strength of reservoirs 208, it would also be possible to fabricate reservoirs 208 as non-reinforced composite materials, or metallic vessels, again with the present structural internal foam.
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.
This application is a continuation-in-part of U.S. patent application Ser. No. 10/907,134, filed Mar. 22, 2005 now U.S. Pat. No. 7,198,111.
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5984016 | Samuelsson | Nov 1999 | A |
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Number | Date | Country | |
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20070107916 A1 | May 2007 | US |
Number | Date | Country | |
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Parent | 10907134 | Mar 2005 | US |
Child | 11621588 | US |