The present invention relates to a vehicle fire suppression system.

Many land vehicles have an internal combustion engine which runs on highly flammable fuel such as petrol, diesel or natural gas. Some vehicles have the capacity to carry a large quantity of highly flammable fuel in a tank. When such a vehicle has a fire the fire can be fuelled by the fuel in the tank leading to a more serious fire, and possibly an explosion. It is known for a vehicle to carry a fire extinguisher canister and for the driver to operate the fire extinguisher canister so as to put out the fire. However, a fire extinguisher canister cannot be used if the driver is either remote from the fire extinguisher canister or is injured. Even if the driver can operate the fire extinguisher canister, there will be an inherent delay, in which time the fire may grow more serious.

It is an aim of the invention to provide an improved vehicle fire suppression system.

According to a first aspect of the invention there is provided a vehicle fire suppression system comprising a fuel supply for housing a combustible fuel, wherein the vehicle fire suppression system comprises a temperature-sensitive safety valve assembly, the temperature- sensitive safety valve assembly being arranged to sense when a predetermined temperature is exceeded, and the temperature-sensitive safety valve assembly being arranged so that, once the predetermined temperature is exceeded, the fuel supply is shut off. In this way, if a vehicle has a fire, the fuel supply is not in fluid communication with the fire. Preferably, the vehicle fire suppression system is arranged to activate after the predetermined temperature is exceeded. The vehicle fire suppression system preferably comprises a fire extinguisher canister, and once the predetermined temperature is exceeded, agent is released from the fire extinguisher canister.

In one preferred embodiment of the invention, the temperature-sensitive safety valve assembly comprises a heat-sensitive sealing means, which is arranged to fail at a predetermined high temperature, the failure of the heat-sensitive sealing means causing the temperature-sensitive safety valve assembly to shut off the fuel supply. The heat-sensitive sealing means may comprise a container which encloses a sealed fluid, the container being designed to fail when the fluid in the container expands. The container may be made of glass, although it may alternatively be made from a non-brittle material which is resistant to vibrational forces encountered by a vehicle.

The temperature-sensitive safety valve assembly preferably comprises a region for holding a pressurised fluid, the region normally being sealed, and the region comprising a heat-sensitive sealing means which further seals the region, wherein, upon failure of the heat-sensitive sealing means, the region is desealed, and the desealing of the region causes the fuel supply to be sealed. Most preferably, the temperature-sensitive safety valve assembly comprises a valve arranged between the fuel supply and the region, the valve being arranged so that normally it can be activated open by pressure of fluid in the region, the opening of the valve causing the opening of an outlet of the fuel supply so that fuel can leave, and failure of the heat-sensitive sealing means allowing the region to de-pressurise, thereby activating the valve to close under the action of a biasing means, thereby closing the outlet of the fuel supply. When the temperature-sensitive safety valve assembly comprises a region for holding a pressurised fluid, and the vehicle comprises a fire extinguisher canister, when the region is de-pressurised, a fire extinguisher agent is preferably released from the canister, preferably by movement of a valve arranged between the region and the fire extinguisher canister. The fire extinguisher agent may be released through the region.

The heat-sensitive sealing means may be arranged inside a passenger compartment of the vehicle, for example on a head restraint of a seat. The heat-sensitive sealing means may be arranged in the vicinity of an engine of the vehicle.

When the temperature-sensitive safety valve assembly comprises a region for holding a pressurised fluid, the region preferably comprises a conduit, such as a copper pipe, the conduit having a plurality of apertures through which the fire extinguisher agent can be released. The conduit may curve so as to generally return back on itself, preferably more than once. The conduit may comprise a plurality of generally straight sections, and a section which curves through approximately 180 degrees. The conduit may curve in only one plane. In this way it can remain compact in the direction perpendicular to the plane so it can be stowed against flat surfaces of the vehicle in an unobtrusive manner. The apertures may be uniformly spaced along the conduit. The apertures may be drilled. The apertures may be oriented in different directions so as to direct a fire extinguisher agent in corresponding different directions.

When the conduit curves in only one plane, the majority of the apertures may be arranged transverse to the plane, preferably substantially all of the apertures are perpendicular to the plane.

The conduit may be arranged in the vicinity of an engine, preferably above an engine, most preferably on an underside of a bonnet hood.

The conduit may be arranged in a vehicle passenger or storage area. The conduit may lie parallel to the plane of the wall or ceiling of the vehicle passenger or storage area.

The valve arranged between the fuel supply and the region is preferably arranged adjacent the fuel supply.

Preferably, once the predetermined temperature is exceeded, the power supply to the key ignition of the vehicle is shut down. In this way, turning the key ignition will not create a spark which can itself cause a fire.

According to a second aspect of the invention there is provided a vehicle fire suppression system comprising a fuel supply for housing a combustible fuel, wherein the vehicle fire suppression system comprises a temperature-sensitive safety valve assembly which is arranged to sense when a predetermined temperature is exceeded, wherein the temperature-sensitive safety valve assembly is arranged so that, once the predetermined temperature is exceeded, the fire suppression system becomes active.

In this way, the fire can be reduced in vigour or put out entirely.

The vehicle fire suppression system may comprise a fire extinguisher canister, and once the predetermined temperature is exceeded, agent is released from the fire extinguisher canister. Preferably, the temperature-sensitive safety valve assembly comprises a heat-sensitive sealing means, which is arranged to fail at a predetermined high temperature, the failure of the heat- sensitive sealing means causing agent to be released from the fire extinguisher canister. Most preferably, the temperature-sensitive safety valve assembly comprises a region for holding a pressurised fluid, the region normally being sealed, and the region comprising a heat-sensitive sealing means which further seals the region, wherein, upon failure of the heat-sensitive sealing means, the region is desealed, and the desealing of the region causes agent to be released from the fire extinguisher.

According to a third aspect of the invention there is provided a vehicle fire suppression system, the vehicle fire suppression system comprising a conduit having an inlet for fluid connection with a fire extinguishing agent, the conduit having a plurality of apertures to allow release of a extinguishing agent. The apertures may be spaced apart by a distance of up to five metres. In this way, the vehicle fire suppression system can emit an extinguishing agent in a plurality of spaced locations.

According to a fourth aspect of the invention there is provided a vehicle comprising a vehicle fire suppression system in accordance with the first, second or third aspects of the invention or any of the consistory clauses relating thereto.

A vehicle fire suppression system will now be described, by way of example only, and with reference to the accompanying drawings, in which:-

FIGURE 1 is a schematic perspective view of part of a vehicle comprising a fire suppression system in accordance with the invention,

FIGURE 2 is a simple schematic view, partly in cut-away, of a temperature-sensitive safety valve assembly in accordance with the invention,

FIGURE 3 is a schematic view of a fire suppression system in accordance with the invention, and

FIGURE 4 is a schematic view showing part of the fire suppression system of Figure 4. Referring to Figure 1 , a vehicle 2 has a fuel tank 4 arranged towards its rear end. The fuel tank 4 is connected via a first pipe 6 and a second pipe 8 to an engine (not shown for clarity) mounted towards the front of the vehicle.

Between the first pipe 6 and the second pipe 8 is arranged a temperature-sensitive valve assembly 10.

A third pipe 9 extends from the temperature-sensitive valve assembly 10 towards the engine at the front of the vehicle 2, so as to allow fuel to be supplied to the engine.

Referring now to Figure 2, the temperature-sensitive safety valve assembly 10 comprises a temperature-sensitive safety valve unit 12, and a regulator 14 for a fuel pipe 16, which fuel pipe 16 becomes first pipe 6 upstream.

The temperature safety valve unit 12 comprises a housing 18, defining inside a cavity, the cavity being in communication with a conduit 20.

The housing 18 comprises an internal valve seat 22, which defines an aperture between the housing 18 and the regulator 14.

A fastener 24 is arranged, at a remote end of the housing 18 for fastening the housing 18 to the regulator 14. The housing 18 comprises a valve stem (or spindle) 26, arranged with a valve head 28 inside the housing cavity and above seat 22. A second valve head 27 is provided at the other end of the stem 26. A spring 30 is arranged around the" part of the stem 26 between the valve head 28 and a wall of the housing 18 and biases the stem 26 upward. The valve stem 22 has a secondary stem 26a, which extends from a second valve head 27, in line with the valve stem 26. The secondary stem 26a has a head 26b at an end remote from the second valve head 27. A diaphragm 32 is arranged in the housing 18 cavity above the valve head 28.

The conduit 20 is made of plastics.

The conduit 20 splits into two conduit arms 20a and 20b. Each conduit arm 20a and 20b has a heat sensitive closure member 34, at one end, which takes the form of a hollow, liquid-filled, glass bulb.

Joining the two closure members 34 is a pipe section 60. Figure 3 shows the pipe section 60 in more detail. The pipe section 60 is made of 8mm copper tubing. The pipe section 60 comprises six parallel lengths of tubing, successive lengths of tubing being joined by curved sections of tubing to form a planar frame.

The pipe section 60 has a plurality of apertures 62 arranged along its length. In the embodiment shown in Figure 4 the apertures 62 are uniformly spaced along the straight sections of the pipe section 60. The apertures 62 all face out of the page in Figure 4 but other arrangements are envisaged such as apertures directed at a range of angles, each angle being transverse to the plane of the pipe section 60.

Referring back to Figure 2, the conduit 20 has another closure member 37, at its other end, which closure member 37 takes the form of a chamber having a one-way valve to allow gas refilling of the conduit 20.

A threaded pipe 38 is provided, in communication with the closure member 37, and directly adjacent thereto, to allow connection of a gas supply and prompt refilling of the conduit 20.

Still looking at Figure 2, the regulator 14 comprises a chamber 40 of dome-like form, which defines an inner cavity. The chamber 40 has an upper aperture defined by a wall 42. The fastener 24 of the housing 18 is threaded onto the outside of the wall 42 after introducing the valve stem 26 into the chamber 40. The chamber 40 has an annular recess 44, which recess houses a diaphragm 46. The valve head 27 of the valve stem 26 acts on the diaphragm 46. An opening 48 in the ceiling of the chamber 40 allows gas to escape from the chamber to the atmosphere.

The pipe 16 comprises a first pipe part 50 and a second pipe part 52, which are, respectively, arranged before and after the temperature-sensitive safety valve unit 12. The first part 50 has an outlet defined by a valve seat 54. The second part 52 has an inlet 56. The outlet 54 and the inlet 56 are both in communication with the internal chamber 40 of the regulator 14. The secondary stem 26a is arranged so that the valve head 26b is located inside the seat 54 of the pipe part 50. Inside the chamber 40, a spring 58 is arranged between an underside of the diaphragm 46 and the first pipe part 50.

Referring to Figure 3, the pressure in the conduit arm 20a upstream of the heat sensitive closure member 34 is about 15 bar. In the pipe section 60, the pressure is O bar (i.e. ambient pressure). The closure member 34 has a metal housing 64 which surrounds a hollow glass capsule 66. Figure 3 shows in broken line detail an inside surface of the hollow glass capsule, and the hollow interior defined thereby, which encloses a liquid. The hollow glass capsule 66 has a brass stem 67 connected to a circular base 68 which is intended to cooperate with a seat 69 of the closure member 34. The closure member 34 is arranged so that when the glass periphery of the hollow glass capsule 66 shatters the stem 67 and base 68 are forced outward under the bias of the fire extinguisher agent fluid and a spring (shown in Figure 3). As it is forced outward, the stem is retained by a guide (also shown in Figure 3). so that the base 68 hits the seat 69 properly. The guide has a fluid permeable side wall (shown in broken line in Figure 3) and a lid (shown in solid line) which defines a circular aperture for the stem 67. The lid and stem fit so as to maintain fluid tight as far as the fluid in the conduit arm 20a is concerned. The stem and base 67, 68 are forced outward until the base 68 cooperates with the seat 69, thereby sealing the line so that fluid can pass, without loss, from the conduit arm 20a into the pipe section 60 (and also from the conduit arm 20b into the pipe section 60). In use, and referring to Figure 2, the first pipe part 50 of the gas pipe 16 is connected to the fuel supply 4, via pipe 6 which is also shown in Figure 1. Ordinarily, the closure member 34 is intact, sealing the region within the conduit 20. In this state, pressure caused by the presence of a high pressure gas (such as air) in the conduit 20 acts on the diaphragm 32 to force the valve head 28 and the valve stem 26 down, against the bias of the spring 30. Consequently, the valve head 26b moves away from the seat 54 to allow fuel therethrough. Fuel is then diverted by the diaphragm 46 into the second pipe part 52 of the pipe 16. In this way, fuel is free to move through the second pipe part 52 of the pipe 16 to other parts, for example, in this case via the pipe 9 towards the engine (not shown).

In the case of a high temperature, for example a fire, the closure member 34 fails. In particular, the liquid in the hollow glass capsule 66 of the closure member 34 expands causing the capsule to explode. Shattered pieces of the glass capsule 66 fall away from the conduit arms 20a, 20b. The pressure in the conduit arm 20a falls causing the valve stem 26 and the valve secondary stem 26a to move towards the conduit arm 20a (i.e. upwards in Figure 1), under the force of the spring 58, until the valve head 26b of the secondary stem 26a moves into sealing contact with the valve seat 54 of the first pipe part 50 of the fuel pipe 16. In this way, the temperature-sensitive safety valve assembly 10 in accordance with the invention quickly, efficiently, cheaply and simply shuts off the fuel pipe 16.

Simultaneously with the above mentioned shutting off of the fuel pipe 16, depressurisation of the conduit 20 causes a valve (not shown for conciseness) arranged between the conduit 20 and a fire extinguisher canister 70 (shown in Figure 1 and Figure 3) to move, thereby allowing a fire extinguishing agent to flow into the conduit 20, and onwards through the conduit arms 20a, 20b and apertures 62 in the pipe section 60, so as to douse the fire.