Warning system in a motor vehicle with a hydrogen storage system

Abstract

Warning system in a motor vehicle having a storage container for hydrogen, in particular in cryogenic form, which, when the vehicle is parked, draws attention to hydrogen escaping into the environment, characterized in that the warning system informs the user of the vehicle and / or, in the case that the vehicle is parked in a space enclosed in the broadest sense, a security control center by means of telemetry about an escape of hydrogen from the storage container derived from signals of a valve device or from the temporal course of pressure and temperature in the storage container.

Description

[0001] The invention relates to a warning system in a motor vehicle having a storage tank for hydrogen, particularly in cryogenic form, which alerts the driver to hydrogen escaping into the environment when the vehicle is parked. For the prior art, reference is made, for example, to DE 10 2004 035 003 A1 and DE 101 61 214 B4.

[0002] It is known that under unfavorable circumstances, a portion of hydrogen can escape unburned and initially unnoticed into the environment from motor vehicles whose propulsion systems are supplied with hydrogen stored in a storage tank. This is undesirable, among other things, due to the high flammability of chemically unbound hydrogen. Nevertheless, in the event of leaks or the rare but not entirely unavoidable so-called "blow-offs" or "boil-offs" in cryogenic tanks or, in general, tanks in which hydrogen is stored in liquid form, a certain amount of hydrogen can escape into the environment.In the case of cryogenic tanks, i.e. storage containers in which the hydrogen is stored in a cryogenic state (either in the liquid state or in a supercritical state under higher pressure), in special situations, namely when the vehicle is parked for a long period of time without hydrogen being taken from the cryogenic tank to supply the drive system or another consumer, the unavoidable low heat input from the environment into the tank can lead to such an intensive pressure increase that a small amount of hydrogen has to be released to the outside, usually into the environment, in order to avoid unacceptably high pressure values ​​in the tank and the resulting risk of the tank bursting.

[0003] In principle, known hydrogen sensors can be installed on the vehicle or in the surrounding area to indicate the presence of hydrogen in the ambient air. The document mentioned above describes that, instead of conventional electrically operated sensors, areas on the vehicle or a room in which the vehicle is parked that may be affected by a hydrogen leak can be coated with a coating that changes color when hydrogen is detected, so that the hydrogen, which itself is invisible, becomes virtually indirectly visible to people.

[0004] These known solutions are practically only effective if a person is in the immediate vicinity of the vehicle and can perceive a signal emitted by the aforementioned sensor system that detects the presence of hydrogen or by a signal generator coupled to it. While a hydrogen sensor system installed in a building or other essentially enclosed space in which a motor vehicle with a hydrogen storage tank is parked can transmit signals indicating the presence of hydrogen to a more distant security control center or similar, this has so far been an indispensable prerequisite for the installation of appropriate sensors in such a space, which could also include, for example, a parking garage equipped with ventilation openings or a ventilation system. However, the latter is not guaranteed or even guaranteed.at least in the “initial phase” of hydrogen-powered vehicles, which are only likely to appear in larger numbers after a long introduction period, are not yet guaranteed across the board.

[0005] US 2010 / 0233562 A1 discloses a gas detection system.

[0006] Therefore, a warning system according to the preamble of claim 1 is to be shown here, which reliably, or at least more reliably than in the prior art, draws attention to the leakage of hydrogen even when there are no persons in the immediate vicinity of the vehicle in the event of a leakage of hydrogen (= object of the present invention).

[0007] The solution to this problem is characterized in that the warning system informs the user of the vehicle and / or, in the case of the vehicle being parked in a space that is closed in the broadest sense, a security control center by telemetry about a leakage of hydrogen from the storage tank derived from signals from a valve device or from the temporal course of pressure and temperature in the storage tank.

[0008] According to the invention, in order to detect a leak of hydrogen into the environment, the vehicle's own data is first evaluated by a warning system which is partially integrated into an electronic control unit. The detection of a leak of hydrogen is therefore no longer dependent on the installation of suitable sensors in a substantially enclosed space in which a vehicle equipped according to the invention is parked. For such detection, corresponding valves provided in the vehicle or in its hydrogen storage and supply system are preferably monitored, in particular a safety valve which controls the release of a small amount of hydrogen in the event of an inadmissibly high pressure increase in the storage container. However, since unwanted leaks can also occur, it is recommended to install a warning system in orto provide one or more hydrogen sensors at a suitable location on the vehicle itself, which respond to the presence of hydrogen and report this to the electronic control unit of the warning system. In particular, this can also be used to detect a leak in a pressure tank as a storage container for hydrogen in non-cryogenic form, which can usually be operated without releasing a portion of the hydrogen. For all tank systems, i.e. for storage containers in which hydrogen is stored in cryogenic form and / or under pressure, it is also possible to conclude that there is an unwanted escape of hydrogen from the temporal progression of the pressure and temperature in the storage container, or more precisely the pressure and temperature of the hydrogen in the storage container, particularly when the hydrogen consumer(s) are switched off.The physical relationship between pressure and temperature of a constant mass of hydrogen in a constant volume is known, so that a deviation from this determined by temperature and pressure measurements indicates a release of hydrogen into the environment.

[0009] In a next step, the warning system can analyze the intensity or extent of the hydrogen leak, i.e., use suitable queries to check whether only a negligible amount of hydrogen appears to have leaked out, or whether a larger or significant amount of hydrogen has entered the environment. At least in the latter case, a warning system according to the invention sends this information wirelessly, and thus suitably processed by telemetry, to the user of the vehicle and / or to a suitable security control center. In the former case, storage for a later time may be sufficient. In the case of a parking garage, this may be a staffed or electronically designed security control center, which can then initiate appropriate measures.Of course, this security control center must be equipped with a suitable receiver for this telemetrically transmitted information, but this also applies to the vehicle user. A suitable option here is their mobile phone, which can also have a suitable "app" (smartphone application) installed. The latter is only an example, however; other non-exhaustive possibilities include emails or a receiver integrated into the vehicle key, and many more.

Claims

[1] Warning system in a motor vehicle having a storage container for hydrogen, in particular in cryogenic form, which alerts the user to hydrogen escaping into the environment when the vehicle is parked, characterized by that the warning system informs the user of the vehicle and / or, if the vehicle is parked in a space which is in the broadest sense of the word enclosed, a security control centre by telemetry of any leakage of hydrogen from the storage tank which is inferred from signals from a valve device or from the temporal progression of pressure and temperature in the storage tank. [2] Warning system according to claim 1, characterized by that an estimate of the amount of hydrogen released is carried out and that only in the event of a significant amount is direct notification given to the user and / or a safety control centre.