Fuel supply system with inert gas storage, motor vehicle, method and computer-readable storage medium

Abstract

The technology disclosed here relates to a fuel supply system for a motor vehicle. The fuel supply system comprises: i) at least one pressure vessel 200 for storing fuel; ii) at least one energy converter 300; iii) at least one fuel-carrying line system 215 connecting the at least one pressure vessel 200 to the at least one energy converter 300; iv) at least one inert gas reservoir 225 fluidly connected to the fuel-carrying line system 215. The fuel supply system is configured to introduce inert gas from the inert gas reservoir 225 into the line system 215 immediately before, during, and / or after a collision of the motor vehicle with another stationary or moving object, so that the fuel concentration in the line system 215 and at a fuel outlet point of the line system 215 is reduced.Furthermore, the technology relates to a motor vehicle, a method and a computer-readable storage medium.

Description

Motor vehicles comprising a fuel cell system are known from the prior art. If a collision with another vehicle or an obstacle occurs, hydrogen may leak from a damaged fuel cell system. Under certain circumstances, a combustible mixture may be formed. The publication DE 10 2008 037 664 A1 belongs to the prior art.It is a preferred object of the technology disclosed herein to reduce or eliminate at least one disadvantage of a prior art solution or to propose an alternative solution. It is in particular a preferred object of the technology disclosed here to configure fuel cell systems in an even more reliable manner without this having an appreciable effect on other parameters such as installation space requirement, weight and / or costs of the fuel cell system. Further preferred objects may result from the advantageous effects of the technology disclosed herein. The object(s) is / are achieved by the subject matter of the independent claims. The dependent claims represent preferred embodiments.The technology disclosed here relates to a fuel supply system for a motor vehicle, in particular a passenger vehicle, a motor bus, a motorcycle or a commercial vehicle. The motor vehicle can be operated, for example, with compressed natural gas (also referred to as CNG) or liquefied natural gas (also referred to as liquid natural gas or LNG) or with hydrogen.The fuel supply system comprises: i) at least one pressure vessel for storing fuel; ii) at least one energy converter; iii) at least one fuel-conducting line system, which connects the at least one pressure vessel to the at least one energy converter; and iv) at least one inert gas reservoir, which is fluidically connected to the fuel-conducting line system. The fuel supply system is configured to introduce inert gas from the inert gas store into the line system i) if a leak has been detected in the line system, and / or ii) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object, such that the fuel concentration in the line system and at a fuel outlet point of the line system is reduced.The at least one pressure vessel serves for storing fuel that is gaseous under ambient conditions. The pressure vessel is generally a composite overlapped pressure vessel provided with a fiber-reinforced layer. The pressure vessel may be, for example, a cryogenic pressure vessel or a high pressure gas vessel. High-pressure gas containers are designed to store fuel permanently at ambient temperatures at a nominal operating pressure (also referred to as nominally working pressure or NWP) of at least 350 barü (= overpressure with respect to atmospheric pressure) or of at least 700 barü. A cryogenic pressure vessel is suitable for storing the fuel at the aforementioned operating pressures even at temperatures which are significantly below the operating temperature of the motor vehicle. Such a pressure vessel can be formed, for example, by a pipe storage system which has a plurality of storage pipes which each have a length-to-diameter ratio with a value of between 5 and 40, preferably between 7 and 25, and particularly preferably between 9 and 15.The at least one energy converter is configured to convert the chemical energy of the fuel into other energy forms, for example into electrical energy and / or into kinetic energy. The energy converter can be, for example, an internal combustion engine or a fuel cell system or fuel cell stack with at least one fuel cell.The fuel cell system is intended, for example, for mobile applications such as motor vehicles, in particular for providing the energy for at least one drive machine for the movement of the motor vehicle. In its simplest form, a fuel cell is an electrochemical energy converter that converts fuel (e.g., hydrogen) and oxidant (e.g., air, oxygen, and peroxides) into reaction products, thereby producing electricity and heat. The fuel cell includes an anode and a cathode separated by an ion selective separator.The fuel cell system includes an anode subsystem formed by the fuel carrying components of the fuel cell system. An anode subsystem may include at least one pressure vessel, at least one tank shut-off valve, at least one pressure reducer, at least one anode supply flow path leading to the anode inlet of the fuel cell stack, an anode space in the fuel cell stack, at least one recirculation flow path leading away from the anode outlet of the fuel cell stack, at least one water separator, at least one anode purge valve, at least one active or passive fuel recirculation conveyor, and further elements. The at least one fuel-conducting line system, which connects the at least one pressure vessel to the at least one energy converter, can be, for example, the anode inflow path. The main task of the anode subsystem is the supply and distribution of fuel to the electrochemically active surfaces of the anode compartment and the discharge of anode off-gas.The fuel supply system may comprise a pressure reducer fluidly connected to the pressure vessel. The pressure reducer is arranged downstream of the at least one pressure vessel and upstream of the energy converter, i.e. in general in the anode subsystem upstream of the at least one fuel cell. The pressure reducer is designed to reduce the fuel inlet pressure present at the inlet of the pressure reducer to a fuel outlet pressure or back pressure present at the outlet of the pressure reducer. In the simplest form, this can be a throttle. As a rule, the pressure reducer comprises a pressure-reducing valve which, despite different input pressures, ensures that a specific output pressure is not exceeded on the output side. The fuel expands in the pressure reducer. Preferably, a first pressure reducer is used and a second or further pressure reducer is used downstream.The pressure in the line system downstream of the pressure reducer is referred to as the medium pressure range. The pressure in the line system upstream of the pressure reducer, i.e. between the pressure reducer and the pressure vessel, is referred to as the high-pressure region. Downstream of the pressure reducer, a further pressure reducer can be provided, which reduces the medium pressure to an even lower level (also low-pressure region). However, such a further pressure reducer does not have to be provided.The at least one inert gas storage device is fluidically connected to the fuel-carrying line system. The intergas reservoir is preferably provided downstream of the pressure reducer in the medium-pressure region. If a further pressure reducer is provided, the inert gas store is preferably provided upstream of the further pressure reducer. The inert gas storage stores the inert gas. As inert gas, it is possible to use, for example, nitrogen, carbon dioxide or a noble gas. The inert gas reservoir is a pressure vessel and can be, for example, a cartridge or else a capsule, or a pressurized can. Advantageously, the cartridge can be designed in such a way that it can be detachably connected to the line system. For this purpose, the inert gas store can be designed to be screwable on. The inert gas storage device is thus advantageously designed to be replaceable. The inert gas storage can have an inert gas storage volume of from 0.01 liter to 1 liter, or from 0.05 liter to 0.5 liter, or from 0.05 liter to 0.25 liter. The inert gas store can be configured to store the inert gas at a pressure of from about 20 bar to about 500 bar or from about 30 bar to about 250 bar or from about 50 bar to about 200 bar or from about 20 bar to about 70 bar. Expediently, the pressure in the inert gas store filled with inert gas is at least 10% or at least 20% or at least 50% or at least 100% or at least 200% higher than the maximum operating pressure in the line system downstream of the pressure reducer, but preferably never higher than the lowest burst pressure of a component installed in the line system. In particular, the inert gas storage volume and the inert gas storage pressure are so large that, in the event of a leak in the line system, the line system can be flushed with a quantity of inert gas at a rate such that the concentration of fuel in the line system and at the fuel outlet point (i.e. the leak point) falls below a limit concentration.The fuel supply system is configured to introduce inert gas from the inert gas storage device into the line system immediately before an imminent object, during and / or immediately after a collision of the motor vehicle with another stationary or moving object, such that the fuel concentration in the line system and at a fuel outlet point of the line system is reduced. The fuel supply system can be configured to detect i) a leakage in the line system, and ii) introduce inert gas into the line system if a leakage in the line system has been detected. The leakage is a leakage that does not occur during the control operation of the fuel supply system. Rather, this is a leakage which only occurs in the event of a malfunction of the BVA, for example due to mechanical damage to the line system or due to improper mounting. The leakage is generally a torn-off or severely damaged line of the line system. Smaller leaks that are below a limit value can be neglected by the BVA. The leakage can be detected by means of corresponding sensor systems. For example, at least one fuel sensor can be provided in the immediate vicinity of the line system, which is configured to detect fuel leakage flows emerging from the line system. Alternatively or additionally, it can be provided that, on the basis of the pressure and temperature changes in the line system and / or by means of a mass flow energy balance, it is detected whether the fuel escapes via leakage points.For introducing the inert gas, the fuel supply system, in particular the control device disclosed here, can be configured to actuate a trigger valve. The trigger valve is configured to interrupt the fluid connection between the inert gas reservoir and the line system. The trigger valve can be actuated by an electrical or electronic trigger signal. If the trigger valve is actuated, the fluid connection between the inert gas reservoir and the line system is released and the inert gas flows into the line system in order to flush this. The combustion gas contained in the line system and the inert gas functioning as a purging gas escape through the leakage point with a comparatively high impulse. At the outlet point, a gas mixture with a comparatively low fuel concentration is thus advantageously produced. The BVA may be configured to actuate the trigger valve if a leak has been detected. The trigger valve can be, for example, a normally closed valve. In a further embodiment, the triggering valve can be designed in such a way that the triggering valve is an irreversibly triggering valve. For example, an electrically actuated bursting element can be provided for this purpose, which closes the inert gas reservoir in a gas-tight manner and is only opened irreversibly by the triggering signal. A rupture element can also be provided in front of or behind the normally closed valve for additional sealing.At least one shut-off valve can be provided in the line system, wherein the fuel supply system can be configured to close the at least one shut-off valve,i) if a leakage in the line system has been detected, and / orii) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object.In particular, the shut-off valve can be the tank shut-off valve. The tank shut-off valve is the valve whose inlet pressure substantially corresponds to the tank pressure. The tank shut-off valve is in particular a normally closed valve. The tank shut-off valve is generally integrated into an on-tank valve. In Regulation (EU) No. 406 / 2010 of the Commission of April 26, 2010 for Carrying out Regulation (EC) No. 79 / 2009 of the European Parlament and the Rate of Approval of Type of Hydrogen-Operated Motor Vehicles, such a tank shut-off valve is also referred to as a first valve. Alternatively or additionally, the anode-side stack shut-off valve can also form the shut-off valve. In an alternative embodiment, it can be provided that the anode-side stack shut-off valve and, if appropriate, the anode purging valve are intentionally opened in the same situation, so that the hydrogen is discharged via the exhaust system, wherein it is diluted further with cathode air. If the tank shut-off valve and / or the anode-side stack shut-off valve is closed, the remaining part of the line system can be flushed more efficiently. Thus, no fresh fuel can flow in from the pressure vessel.The system disclosed herein further includes at least one controller. The control device is configured, among other things, to carry out the method steps disclosed here. For this purpose, the control device can at least partially and preferably completely control (closed loop control) or control (open loop control) the actuators of the system based on provided signals. The control device can influence at least the fuel cell system, in particular the anode subsystem. Alternatively or additionally, the control device can also be integrated in another control device, e.g. in a higher-order control device. The control device can interact with further control devices of the motor vehicle. An imminent collision is a pre-crash situation. This is assumed, for example, if an imminent collision is predicted with sufficient probability even before this collision actually takes place. This prediction therefore takes place here before the collision or the contact between the motor vehicle and the object. Methods exist for triggering airbags to detect such pre-crash situations.The technology disclosed herein further relates to a method for purging gaseous fuel from a fuel supply system of a motor vehicle, in particular the BVA disclosed herein. The method can comprise the step of: introducing inert gas from an inert gas store into the fuel-conducting line system,i) if a leakage in the line system has been detected, and / orii) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object.The method may further comprise the step of: closing at least one shut-off valve provided in the line system,i) if a leak in the line system ( 215) has been detected, and / orii) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object.The technology disclosed herein will be explained in more detail below with reference to FIG. 1.FIG. 1 schematically shows the BVA disclosed herein. It comprises a pressure vessel 200. Here, the BVA is a fuel cell system. Fuel is stored in the pressure vessel 200, for example hydrogen at 700 bar. The pressure vessel 200 provides hydrogen for the energy converter 300, here a fuel cell stack with a plurality of fuel cells which are operated at a lower pressure level, for example 0.5 to 1 barü. At one end of the pressure vessel 200, a tank shut-off valve 210 is provided. Instead of just one pressure vessel 200 with one tank shut-off valve 210, a plurality of pressure vessels 200 with a plurality of tank shut-off valves 210 could likewise be provided. In the system shown here, two pressure reducers 222, 224 are also provided. The first pressure reducer 224 lowers the pressure of 700 bar to an intermediate pressure level of, for example, 2 to 40 bar or 12 to 18 bar (intermediate pressure range). The second pressure reducer 224 lowers the pressure from the medium pressure level to the low pressure of the fuel cells. In order to prevent the pipelines of the line system 215 from bursting in the event of a malfunction of the pressure reducers 222, 224, a pressure relief valve is provided here downstream of the first and second pressure reducers 222, 224 (not shown here). In the recirculation flow path 216 from the anode subsystem, a water separator 232, an anode purge valve 238, a recirculation pump 236, and a venturi nozzle 234 are provided downstream of the fuel cell stack. The inert gas reservoir 225 is connected to the fuel-conducting line system 215 downstream of the first pressure reducer 224 and upstream of the second pressure reducer 222. Here, the anode purge line 239 connects the anode purge valve 238 to the cathode exhaust line 416 that starts downstream from the cathode K of the fuel cell stack and ends in the environment. A catalyst surface may be provided in this exhaust conduit 416 (not shown). In a further embodiment, the anode purging line 239 opens into the cathode supply line 415 upstream of the cathode, in particular downstream of the cathode-side stack shut-off valve 430. The direction of flow of the fuel and of the ambient air are represented here by arrows. The fuel cell system is installed in a motor vehicle (not shown).List of reference characters300 Energy converter A Anode chamber 200 Pressure vessel 210 Tank shut-off valve 215 Line system 216 Recirculation flow path 222 Pressure reducer 225 Intergas accumulator 224 Pressure reducer 232 Water separator 238 Anode purge valve 234 Recirculation jet pump 236 Recirculation conveyor 239 Anode purge line K Cathode chamber 410 Oxidizing agent conveyor 415 Cathode inflow path 420 Heat exchanger 430 Feed line stack shut-off valve 440 Exhaust gas stack shut-off valve 416 Cathode exhaust gas path 460 Fuel cell bypass

Claims

A fuel supply system for a motor vehicle, comprising: a. at least one pressure vessel (200) for storing fuel; b. at least one energy converter (300); c. at least one fuel-conducting line system (215) which connects the at least one pressure vessel (200) to the at least one energy converter (300); and d. at least one inert gas store (225) which is fluidically connected to the fuel-conducting line system (215); e. wherein the fuel supply system is configured to introduce inert gas from the inert gas store (225) into the line system (215) iii) if a leak has been detected in the line system (215), and / or iv) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object.The fuel supply system of claim 1, further comprising a pressure reducer (224) fluidly connected to the pressure vessel (200), wherein the inter-gas reservoir (225) is provided downstream of the pressure reducer (224).Fuel supply system according to Claim 1 or 2, wherein at least one shut-off valve (210, 230) is provided in the line system (215), and wherein the fuel supply system is configured to close the at least one shut-off valve (210, 230), i) if a leak has been detected in the line system (215), and / or ii) immediately before an imminent collision, during a collision and / or immediately after a collision of the motor vehicle with another stationary or moving object.The fuel supply system according to claim 3, wherein the fuel supply system is configured to close the at least one shut-off valve (210, 230) if an imminent collision of the moving motor vehicle with another stationary or moving object has been detected.Fuel supply system according to one of the preceding claims, wherein the inert gas store (225) is designed as a cartridge which is designed to be screwed to the line system (215).Fuel supply system according to one of the preceding claims, further comprising a trigger valve which interrupts the fluid connection between the inert gas store (225) and the line system (215), wherein the trigger valve can be actuated by a trigger signal if the line system (215) has a leakage.Method for flushing out gaseous fuel from a fuel supply system of a motor vehicle, wherein the fuel supply system has a fuel-conducting line system (215) which connects at least one pressure vessel (200) to at least one energy converter (300), comprising the step of: introducing inert gas from an inert gas store (225) into the fuel-conducting line system (215), i) if a leakage has been detected in the line system (215), and / or ii) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object.The method of claim 7, further comprising the step of: closing at least one shut-off valve (210, 230) provided in the conduit system (215), i) if a leak in the conduit system (215) has been detected, and / or ii) immediately before an imminent collision, during a collision and / or after a collision of the motor vehicle with another stationary or moving object.A computer readable storage medium having stored thereon program instructions which, when executed by a microprocessor, cause the microprocessor to perform a method according to claim 7 or 8.Motor vehicle, - comprising a fuel supply installation according to one of the preceding claims 1 to 6; and / or - comprising a computer-readable storage medium according to claim 9; and / or - configured to carry out at least one of the methods according to claim 7 or 8.

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