FIRE EXTINGUISHING SYSTEM FOR A VEHICLE TEST STAND

Abstract

Fire extinguishing system for a test stand for vehicles (400), at least with a test area (100), a fixing element (101) for holding the vehicle (400) in the test area (100) and a fire alarm system (500), characterized in that the fixing element (101) can be opened in case of fire, and a linear drive is provided to move the vehicle (400) from the test area (100) into an extinguishing area (200).

Description

The invention relates to a fire extinguishing system for a test stand for vehicles, comprising at least one test area, a fixing element for holding the vehicle in the test area, and a fire alarm system. The vehicles to be tested are typically fixed in a precisely defined position using tension straps as fixing elements in order to enable accurate measurement regardless of the forces and moments occurring. Existing vehicle test benches are generally designed with fire protection in mind for vehicles with combustion engines. They can usually also be used for testing electric and hybrid vehicles. However, the high energy densities of modern batteries present new fire protection challenges. With modern traction batteries, which are commonly found in such vehicles, the so-called "thermal runaway" is particularly problematic, as extremely rapid action is required in the event of a malfunction to protect people and infrastructure. Documents such as DE 44 44 441 C1, DE 10 2008 021 449 A1, DE 10 2013 017 068 A1, and DE 10 2015 104 380 A1 are known from the state of the art in this area. When certain traction batteries burn, temperatures exceeding 660°C can be reached. This represents an enormous thermal stress for a test bench. In addition, large quantities of combustion smoke from the battery fire and further smoke from rapidly developing secondary fires on the vehicle are to be expected. During the subsequent extinguishing process, the surrounding area cools down considerably, further stressing the test bench. Besides the anticipated fire and smoke damage, the large quantities of extinguishing agents required, such as water or emulsion, which must be introduced into the building by emergency responders, can also cause significant damage. The aim of the invention is to achieve the most effective and flexible fire extinguishing system possible for a test bench. According to the invention, this is achieved by making the fixing element openable in case of fire, and by arranging a linear drive on the test bench in such a way as to move the vehicle from the test area into a fire extinguishing area. The key feature of the present invention is that the actual extinguishing process is not carried out in the vehicle's measuring position, but rather at a distance. As soon as the fire alarm system detects a potential fire, either via external sensors or sensors within the vehicle, the vehicle's restraint mechanism is opened to allow its removal from the testing area. The restraint mechanism can, of course, also be opened manually. Ideally, firefighting measures or smoke containment can begin simultaneously with the removal of the vehicle. The present invention is particularly suitable for use in roller test benches. A winch is particularly well-suited as a linear actuator because it is both cost-effective and highly reliable. Ideally, the linear actuator is electrically powered, although any other type of drive is also conceivable. The vehicle itself can be pulled out of the test area, or an auxiliary frame, such as one running on rails, can be used to pull the vehicle along. A preferred embodiment of the invention provides that the extinguishing area is designed as a floodable container, preferably connected to it via a ramp. This allows for particularly rapid extinguishing by partially or completely immersing the vehicle in an extinguishing medium. Furthermore, a large amount of energy can be absorbed without difficulty. Alternatively, the floodable container can be closed at the top by a grid, allowing the vehicle to be pulled onto this grid and the extinguishing medium sprayed from above to be collected in the floodable container below the vehicle and potentially recycled. Alternatively, this container can also be a mobile unit that is only set up during ongoing test bench operation. In this case, the front wall of the container can be hinged to form an entry ramp that can be tightly closed. The device according to the invention can be flexibly and, above all, mobilised integrated into existing test benches, thus offering the advantage that any type of test bench can be retrofitted with the fire extinguishing system according to the invention in a simple manner. Existing test benches and infrastructure can therefore be used with hybrid or electric vehicles using this invention, without the traction batteries posing a high risk. Preferably, the at least one fixing element can be opened electronically and is connected to the fire alarm system. This largely avoids delays in the event of a fire and eliminates the need for manual intervention, although manual triggering is also possible. To prevent thermal damage in the event of particularly rapid fire spread, as well as smoke damage, cooling and extinguishing water nozzles may be installed in the test area to prevent the fire from spreading to the test stand and to prevent damage from overheating or smoke. These nozzles are not designed to extinguish a fire, but rather to be dimensioned so that the extinguishing medium does not damage the equipment in the test area, while simultaneously preventing the fire from spreading beyond the vehicle in the short time between detection and removal of the vehicle, reducing heat radiation, and ensuring smoke suppression / smoke washout. In particular, it is advantageous if at least one cooling and extinguishing water nozzle has an elongated discharge opening, so that it forms a water curtain. Particularly advantageous is the arrangement of several cooling and extinguishing water nozzles on each side of the vehicle, forming a water curtain. To minimize the required amount of extinguishing agent, nozzles that have already passed through can be deactivated. It is also possible to arrange these nozzles so that they move with the vehicle during towing, thus ensuring this water curtain is maintained along the entire towing route. Further fire safety improvements can be achieved by installing at least one connecting door between the test area and the extinguishing zone. This door should preferably be electronically operated and connected to the fire alarm system. This minimizes the risk of the extinguishing process affecting the test area. Furthermore, it is particularly important for acoustic measurements to be able to completely close off or selectively open the test area. If there is sufficient space within the test rig and adequate ceiling load capacity, this connecting door is not strictly necessary, as the resulting water curtain can also provide sufficient separation. The present invention will now be explained in more detail with reference to the embodiments shown in the figures. Figure 1 shows a first embodiment of the invention in a schematic top view; and Figure 2 shows an alternative embodiment in a representation corresponding to Figure 1. Fig. 1 shows a fire extinguishing system according to the invention with a test area 100 and a fire extinguishing area 200. A vehicle 400 is shown, which is currently being tested and is therefore located in the test area 100. A fixing element 101 and a rope 202 are attached to it. The fixing element 101 serves to fix the position of the vehicle 400 in the test area 100 during the test. The fixing element 101 is also attached in the test area 100, wherein the fixing element 101 is designed to be electronically detachable from the test area 100, and is connected to a fire alarm system 500. The fire alarm system 500 is connected to fire sensors 105. In fire suppression zone 200, a winch 201 is arranged, onto which the cable 202 can be wound. The winch 201 is connected to an electric drive, which in turn is connected to the fire alarm system 500. Part of the extinguishing area 200 is designed as a floodable container 210, which is formed by a substantially cuboid depression in the floor of the extinguishing area 200. The wall of the floodable container 210, which is closest to the test area 100, is not vertical but arranged at an angle, so that it forms a ramp 211. The depth of the floodable container 210 can be approximately the same as the height of the vehicle 400 to allow for almost complete immersion of the vehicle 400. This enables submersible firefighting, but is associated with high water consumption and requires a sufficiently rapid water supply to quickly fill the floodable container 210 when needed, unless it is permanently filled with extinguishing agent. Alternatively, the floodable tank 210 can also be designed to be significantly shallower. Extinguishing can then be carried out primarily via extinguishing nozzles 250, which spray water onto the vehicle 400. The excess water is collected in the floodable tank 210 and can be returned to the extinguishing water supply. This allows for a significantly more economical use of the extinguishing water. Alternatively, the floodable container can be closed by a grid 212. This allows the vehicle to be driven into the extinguishing area at ground level. This design is shown in Fig. 2. Parallel to the sides of the vehicle 400, nozzles 150 are arranged to form a water curtain. These extend linearly towards the extinguishing area 200 to envelop the vehicle laterally and above. This reduces the thermal stress on the test area, prevents the fire from spreading to the building, and also serves to suppress and wash out fire smoke. Test area 100 and extinguishing area 200 are connected via a connecting corridor 300. This corridor is separated from the test area and the extinguishing area by connecting doors 310 and 311. The connecting door to test area 310 can be designed to shield against interference signals in order to enable the most accurate measurements possible in test area 100. Specifically, an acoustic test rig is shown. Test area 100 is connected to the rest of the building only via elastic joints. The interior walls of test area 100 and the inner part of the connecting door to test area 310 are typically lined with acoustic wedges to prevent sound reflections. Acoustic wedges are usually made of non-combustible acoustic materials, but if soiling occurs (oil, soot, etc.), they may also need to be classified as combustible – however, in principle, any type of test rig is suitable for the invention. The connecting door to fire compartment 311 is designed as a tightly closing door. Both connecting doors 310 and 311 can be opened electronically and are electrically connected to the fire alarm system 500. Under normal operating conditions, connecting doors 310 and 311 are closed, and vehicle 400 is located in test area 100. If a fire is detected by the fire alarm system 500 during the test, the test is aborted and the extinguishing procedure begins. The nozzles 150 are immediately supplied with water to prevent the fire from spreading and to avoid smoke damage. Subsequently, the fixing element 101 is released by the fire alarm system 500, the connecting doors 310 and 311 are opened, and the pulley 201 is activated. The vehicle 400 is then pulled through the connecting corridor 300 into the extinguishing area 200. If the floodable container 210 is designed for submersible extinguishing, the fire alarm system 500 can start the filling process immediately after fire detection. Otherwise, the supply to the extinguishing nozzles 250 begins when the vehicle 400 enters the floodable container 210, or, in the case of mobile containers, after the ramp is closed or the container is prepared for uprighting. If vehicle 400 is located in fire zone 200, the connecting door to fire zone 311 can be closed. This seals off fire zone 200. Special ventilation may be provided for fire zone 200 to extract combustion gases, particularly those containing toxic products from battery or accumulator combustion.

Claims

Fire extinguishing system for a test stand for vehicles (400), at least with a test area (100), a fixing element (101) for holding the vehicle (400) in the test area (100) and a fire alarm system (500), characterized in that the fixing element (101) can be opened in case of fire, and a linear drive is provided to move the vehicle (400) from the test area (100) into an extinguishing area (200). Fire extinguishing system according to claim 1, characterized in that the linear drive is designed as a cable winch (201) which is electrically or manually driven. Fire extinguishing system according to claim 1 or 2, characterized in that the extinguishing area (200) is designed as a floodable container (210) or is connected to it. Fire extinguishing system according to claim 1 or 2, characterized in that the extinguishing area (200) is designed as a floodable container (210) and that it is closed off at the top by a grid (212). Fire extinguishing system according to one of claims 1 to 4, characterized in that the at least one fixing element (101) is electronically openable and that it is connected to the fire alarm system (500). Fire extinguishing system according to one of claims 1 to 5, characterized in that cooling and extinguishing water nozzles (150) are arranged in the test area (100) to prevent the fire from spreading to the surroundings and damage from overheating. Fire extinguishing system according to claim 6, characterized in that at least one cooling and extinguishing water nozzle (150) has an elongated discharge opening, such that it forms a water curtain which preferably surrounds the vehicle (400). Fire extinguishing system according to claim 6 or 7, characterized in that several cooling and extinguishing water nozzles (150) are arranged on either side of the vehicle (400) so that they form a water curtain. Fire extinguishing system according to one of claims 1 to 8, characterized in that at least one connecting door (310, 311) is arranged between the test area (100) and the extinguishing area (200), which is preferably electronically openable and is connected to the fire alarm system (500). Fire extinguishing system according to claim 9, characterized in that a connecting corridor (300) is arranged between the test area (100) and the extinguishing area (200), which can be separated from the test area (100) and preferably from the extinguishing area (200) by connecting doors (310, 311).

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