DE102016204900A1 - Motor vehicle with a reserve storage device and method for operating the motor vehicle - Google Patents

Abstract

The technology disclosed herein relates to a motor vehicle and a method of operating the motor vehicle disclosed herein. The method includes the step of providing fuel through the reserve storage device when the amount of fuel in the pressure vessel system is less than a fuel amount limit.

Description

The technology disclosed herein relates to a motor vehicle, in particular a fuel cell powered motor vehicle, having a reserve storage device. Furthermore, the technology disclosed herein relates to a method of operating such a motor vehicle.

Known from the prior art are fuel cell powered vehicles and other hydrogen powered vehicles. Such vehicles are reliant on gas stations where the vehicles can be refueled with hydrogen as fuel. Due to the currently relatively poorly developed hydrogen fueling station network, there is an increased risk that a hydrogen-powered motor vehicle will remain lying on the way to the filling station with an empty tank. However, gaseous fuels such as hydrogen can not be transported in previously known reserve canisters for gasoline or diesel.

There is therefore a need to provide a fuel reserve for such vehicles powered by gaseous fuels under ambient conditions. It is a further object of the technology disclosed herein to reduce or eliminate the disadvantages of the prior art solutions. Other objects arise from the beneficial effects of the technology disclosed herein. The object (s) is / are solved by the subject matter of the independent claims. The dependent claims are preferred embodiments.

The technology disclosed herein relates to a motor vehicle which can be operated with a gaseous fuel under ambient conditions. The motor vehicle comprises at least one pressure vessel system for storing fuel.

The pressure vessel system comprises at least one pressure vessel for storing fuel for a motor vehicle. The pressure vessel can be used in a motor vehicle which is operated, for example, with compressed natural gas (CNG), liquefied natural gas (LNG) or with hydrogen. Such a pressure vessel may be, for example, a cryogenic pressure vessel or a high-pressure gas vessel. High pressure gas container systems are designed to maintain fuel (e.g., hydrogen) at ambient temperatures substantially at a max. Operating pressure (also called maximum operating pressure or MOP) of about 350 barü (= overpressure relative to the atmospheric pressure), further preferably of about 500 barü and more preferably of about 700 barü store. The cryogenic pressure vessel system comprises a cryogenic pressure vessel. The cryogenic pressure vessel may store fuel in the liquid or supercritical state. A supercritical state of aggregation is a thermodynamic state of a substance which has a higher temperature and a higher pressure than the critical point. For hydrogen, the critical point is 33.18 K and 13.0 bar. A cryogenic pressure vessel is particularly suitable for storing the fuel at temperatures significantly below the operating temperature (meaning the temperature range of the vehicle environment in which the vehicle is to be operated) of the motor vehicle, for example at least 50 Kelvin, preferably at least 100 Kelvin or At least 150 Kelvin below the operating temperature of the motor vehicle (usually about -40 ° C to about + 85 ° C). The fuel may be, for example, hydrogen, which is stored at temperatures of about 34 K to 360 K in the cryogenic pressure vessel. The cryogenic pressure vessel may in particular comprise an inner container which is designed for max. Operating pressures (MOPs) up to about 350 barü (= overpressure relative to the atmospheric pressure), preferably up to about 500 barü, and particularly preferably up to about 700 barü.

Furthermore, the motor vehicle comprises at least one fuel consumer. The fuel consumer may be, for example, a fuel cell system with at least one fuel cell.

The fuel cell system is suitable, for example, for providing the energy for at least one drive machine for locomotion of the motor vehicle. In its simplest form, a fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, producing electricity and heat. The fuel cell includes an anode and a cathode separated by an ion-selective or ion-permeable separator. The anode has a supply for a fuel to the anode. Preferred fuels are: hydrogen, low molecular weight alcohol, biofuels, or liquefied natural gas. The cathode has, for example, a supply of oxidizing agent. Preferred oxidizing agents are, for example, air, oxygen and peroxides. The ion-selective separator can be designed, for example, as a proton exchange membrane (PEM). Preferably, a cation-selective polymer electrolyte membrane is used. Materials for such a membrane are, for example: Nafion ^®, Flemion ^® and Aciplex ^®. A fuel cell system comprises at least a fuel cell and peripheral system components (BOP components), which can be used in the operation of at least one fuel cell. As a rule, several fuel cells are combined to form a fuel cell stack or stack.

Further, the motor vehicle comprises at least one of the at least one pressure vessel separately formed reserve memory device. The reserve storage device is designed to generate the fuel that can be consumed by the fuel consumer from at least one substance that is liquid and / or solid under atmospheric conditions. The term "liquid and / or solid substance" is intended to include both pure substances and mixtures of substances in solid and / or liquid states. Normal atmospheric conditions are the normal conditions of the environment in which the motor vehicle is operated. The pressure vessel system and the at least one reserve storage device are fluidly connected to the at least one fuel consumer. In particular, the pressure vessel system and the at least one reserve storage device may be selectively fluidly connected to the fuel consumer. This means that, for example, via a multi-way valve, either the pressure vessel system or the at least one reserve storage device with the fuel consumer can be fluidly connected. Likewise, other forms of fluid flow control are conceivable.

Preferably, the motor vehicle further comprises at least one control unit which is designed to control the reserve storage device and / or the fluid connection to the fuel consumer such that the reserve storage device provides fuel to the fuel consumer when the fuel quantity in the pressure vessel system falls below a fuel quantity limit value. In particular, the at least one control device can be set up to supply fuel to the fuel consumer by means of the reserve storage device when the at least one pressure vessel of the pressure vessel system is empty. "Empty" is the at least one pressure vessel when the amount of fuel contained in the pressure vessel system is no longer economically and / or technically feasible removed.

In addition, it can be provided that a corresponding warning is already displayed to the vehicle driver even if there is a small utilizable remaining quantity of fuel in the at least one pressure vessel of the pressure vessel system. Seen in this way, in addition the previous reserve function can be used, as it is known, for example, from motor vehicles with conventional internal combustion engines.

Preferably, the reserve storage device is fluidly connected to a fluid reservoir of the motor vehicle. For example, the reserve storage device may be connected to a product water supply. Such a product water supply can, for example, be provided downstream of a fuel cell. In such a product water supply, for example, the product water recovered by a condenser from the fuel cell exhaust gas can be stored. Furthermore, the liquid reservoir may be a liquid reservoir of the cooling system and / or the windscreen wiper system of the motor vehicle or these systems themselves.

Suitably, the reserve storage device may comprise a refilling opening, through which the at least one substance is refillable. Such a refill opening is preferably arranged easily accessible to the vehicle driver or to the service personnel. For example, such a refilling opening can be arranged in the upper region of the engine compartment, comparable with refilling openings for windscreen water or engine oil.

Further preferably, the reserve storage device may comprise a replaceable cartridge. In particular, the at least one under atmospheric conditions liquid and / or solid material may be stored in the replaceable cartridge. The replaceable cartridge can be designed, for example, as a container in which the substance is stored and which can be fluid-connected via a coupling with the at least one fuel consumer.

Particularly preferably, the at least one reserve storage device is designed such that a chemical reaction can take place in the reserve storage device. Particularly preferably, the reserve storage device is a tilting apparatus.

A Kipp'scher apparatus as such is known. The tilting apparatus comprises, for example, three volumes arranged one above the other. The upper volume is fluidly connected via a riser to a lowermost volume. The upper volume is provided gas-tight on a medium volume. At the middle volume, a withdrawal line for removal of the fuel is provided. The middle volume is further fluidly connected to the lower volume, wherein between the middle volume and the lower volume a sieve or is arranged similar, so that no solid material can fall into the lower volume, but gases and liquids, however, can transgress.

• – Bereitstellen von Brennstoff durch die hier offenbarte Reservespeichereinrichtung, wenn die Brennstoffmenge in dem mindestens einen Druckbehälter des Druckbehältersystems einen Brennstoffmengengrenzwert unterscheitet.

The technology disclosed herein further includes a method of operating the motor vehicle disclosed herein. The method comprises the step:

• Providing fuel through the reserve storage device disclosed herein when the amount of fuel in the at least one pressure vessel of the pressure vessel system undershoots a fuel amount limit.

• – Zuführen von einem wasserhaltigen Gemisch zu einem in der Reservespeichereinrichtung gespeicherten Stoff (= gespeichertes Material), dass ein Alkalimetall und/oder ein Erdalkalimetall aufweist, sodass diese Metalle und das wasserhaltige Gemisch unter Abspaltung von Wasserstoff miteinander reagieren.

The provision of fuel by the reserve storage device may include the step of:

• - Supplying a water-containing mixture to a substance stored in the reserve storage device (= stored material), which comprises an alkali metal and / or an alkaline earth metal, so that these metals and the water-containing mixture with the elimination of hydrogen react with each other.

The alkali metals are the chemical elements lithium, sodium, potassium, rubidium, cesium and francium from the first main group of the periodic table. The reaction with water to form alkali metal hydroxides proceeds with liberation of hydrogen according to the following reaction equation 1: 2M + 2H ₂ O → 2MOH + H ₂
where the symbol M: an alkali metal, H ₂ O: Water, MOH: an alkali metal hydroxide, and H2 Represents hydrogen.

Alkaline earth metals are the elements of the 2nd main group of the periodic table. They include the elements beryllium, magnesium, calcium, strontium, barium and radium.

The reaction with water to form alkaline earth metal hydroxides proceeds with liberation of hydrogen according to the following reaction equation 2: Me + 2H ₂ O → Me (OH) ₂ + H ₂
where the symbol me: an alkaline earth metal, H ₂ O: Water, Me (OH) ₂ : an alkaline earth metal hydroxide, and H2 Represents hydrogen.

The substance preferably comprises a volume fraction of alkali metal and / or of alkaline earth metal of at least 70% or at least 80%, preferably of at least 90%, and particularly preferably of 100%.

Preferably, the aqueous mixture may comprise product water which may be taken from the exhaust gases of the fuel cell system disclosed herein. Alternatively or additionally, the water-containing mixture can be taken from the cooling circuit and / or the windscreen wiper system of the motor vehicle. Moreover, again alternatively or additionally conceivable that the product water is already stored in the cartridge.

In addition to the aforementioned reactions of the alkali metals or alkaline earth metals with water, it is also conceivable that other reactions take place in the reserve storage device, in which fuel, especially hydrogen, are released. Further, it is conceivable that the hydrous mixture is supplied to a substance stored in the reserve storage device (= stored material) comprising sodium silicide and / or sodium borohydride, whereby hydrogen can be released. Preferably comprises the fabric has a volume fraction of sodium silicide and / or sodium borohydride of at least 70% or at least 80%, preferably of at least 90%, and more preferably of 100%.

For example, it is conceivable that zinc shavings and hydrochloric acid react with each other, whereby hydrogen is released. The zinc shavings and the hydrochloric acid could be stored, for example, in a suitably designed exchangeable cartridge, wherein expediently during or after connection of the cartridge to the fuel cell system, the two reactants are brought into contact with each other. The fuel can furthermore preferably be stored in a liquid hydrogen carrier, for example a liquid organic hydrogen carrier (LOHC) and / or in a refillable metal hydride reservoir. Such liquid organic hydrogen carriers and / or metal hydride storage as such are known. For example, toluene can be used as the LOHC storage system. An advantage of the aforementioned system with elements of the first and second main group is that the water-containing mixture required for the reaction is carried anyway. Therefore, it is thus possible to provide a comparatively lightweight, compact reserve memory system which, moreover, can be realized comparatively favorably.

The technology disclosed here will now be described with reference to the schematic 1 explained in more detail.

The pressure vessel system 110 here comprises at least one high-pressure accumulator, which via a sampling line 406 with a pressure reducer 420 connected is. The anode feed line 402 connects the pressure reducer 420 with the anode 220 the fuel cell 200 , The cathode 210 the fuel cell 200 and the other elements of the cathode feed system will not be further explained here. The fuel cell exhaust pipe 302 connects the fuel cell 200 with the condenser 310 , In the condenser 310 Water is separated from the fuel cell exhaust gas before the fuel cell exhaust gas through the exhaust pipe 306 the system leaves. By the Kondenserleitung 304 the separated product water enters the product water supply 320 , The product water supply 320 is here via a liquid supply line 126 with the reserve storage device 120 connected. The supply of product water in the reserve storage device 120 can here, for example, by a liquid valve 322 to be controlled. The reserve storage device 120 For example, it may comprise a container storing the liquid and / or particulate matter which is liquid under atmospheric conditions. For example, a substance stored in the container comprising an alkali metal and / or an alkaline earth metal can be used as the reactant or substance. The reserve storage device 120 can be configured for example as Kipp'scher apparatus.

The reserve storage device 120 may include, for example, a replaceable cartridge or a permanently installed container, the example. A refill opening 124 having. One or more reactants can be introduced through the refill opening, for example an alkali metal / alkaline earth metal and water. The reserve storage device 120 here is about a reserve fuel supply line 404 with the fuel consumer 200 , here a fuel cell, connected. According to the 1 ends the reserve fuel supply line 404 upstream of the pressure reducer 420 , It is also conceivable that the reserve fuel supply line 404 downstream of the pressure reducer 420 into the anode feed line 402 empties. The reserve fuel valve 122 is here in the reserve fuel supply line 404 arranged. In the 1 not shown is the at least one control unit, which, for example, the pressure vessel valve 410 and the reserve fuel valve 122 such that selectively the pressure vessel system 110 or the reserve memory device 120 with the fuel consumer 200 fluidly connected. Likewise, the control unit is appropriately set up, by opening and closing the liquid valve 322 the chemical reaction in the reserve storage device 120 to initiate when the amount of fuel in the pressure vessel system 110 falls below a fuel quantity limit. Likewise, other control mechanisms for controlling the chemical reaction to produce the reserve fuel are conceivable.

In other words, according to the technology disclosed here, it is provided that a driver can fall back on a reserve device installed in the vehicle when the normal hydrogen tank is empty. In this reserve device, a certain supply of a chemical substance is stored, which can release hydrogen on contact with water. For this purpose, preferably alkali metals (Li, Na, K, ...) or alkaline earth metals (Be, Mg, Ca, ...) come into question. The reaction of these chemical substances preferably takes place in a reaction space which withstands pressures of up to about 50 bar and which is fluid-connected to the fuel cell. Particularly preferred is the reserve memory device 120 even this reaction space. For example, overpressure valves and / or pressure regulating devices can be provided between the reaction space and the fuel cell. The water necessary for the reaction can either be carried separately for this purpose, be taken from other water supplies in the motor vehicle (eg cooling water supply or "wastewater" of the fuel cell) or supplied by the user (eg by drinking bottle). Even normal drinks get sufficient water for this purpose and could also be supplied via a corresponding filling opening. The technology disclosed here serves as an emergency measure to provide the vehicle drive, for example a fuel cell, with sufficient hydrogen even when the main tank is empty in order to reach the next hydrogen filling station.

The foregoing description of the present invention is for illustrative purposes only, and not for the purpose of limiting the invention. Various changes and modifications are possible within the scope of the invention without departing from the scope of the invention and its equivalents.

LIST OF REFERENCE NUMBERS

110

Pressure vessel system

120

Reserve storage device

122

Reserve fuel valve

124

refill

126

liquid supply

200

fuel consumers

302

Fuel cell exhaust line

304

Kondenserleitung

306

exhaust pipe

310

condenser

320

liquid storage

320

Product water storage

322

liquid valve

406

withdrawal line

402

Anodenzuführleitung

404

Reservebrennstoffzuführleitung

410

Pressure vessel valve

420

pressure reducer

Claims (10)

Motor vehicle comprising: - a pressure vessel system ( 110 ) for storing fuel; and - at least one reserve storage device ( 120 ), the reserve memory device ( 120 ) is designed to generate the fuel from at least one under atmospheric conditions liquid and / or solid substance; and wherein the pressure vessel system ( 110 ) and the at least one reserve memory device ( 120 ) with at least one fuel consumer ( 200 ) are fluidly connected. Motor vehicle according to claim 1, wherein the reserve memory device ( 120 ) is adapted to supply a hydrous mixture to a substance comprising an alkali metal and / or an alkaline earth metal. Motor vehicle according to claim 1 or 2, wherein the reserve memory device ( 120 ) is adapted to supply a hydrous mixture to a substance comprising sodium silicide and / or sodium borohydride. Motor vehicle according to one of the preceding claims, wherein the reserve memory device ( 120 ) with a liquid supply ( 320 ) of the motor vehicle is connected. Motor vehicle according to one of the preceding claims, wherein the reserve memory device ( 120 ) a refill opening ( 124 ), by which the at least one substance is refillable; and / or wherein the reserve storage device ( 120 ) is designed as a replaceable cartridge, in which the at least one atmospheric and / or solid material is stored under atmospheric conditions. Method for operating a motor vehicle according to one of the preceding claims, comprising the step of: - providing fuel through the reserve storage device ( 120 ), if the fuel quantity in the pressure vessel system ( 110 ) falls below a fuel quantity limit. The method of claim 6, wherein said providing of fuel by said backup storage means (10). 120 ) comprising the step of: - supplying a hydrous mixture to a substance comprising alkali metal and / or alkaline earth metal; and / or supplying a water-containing mixture to a substance comprising sodium silicide and / or sodium borohydride.  The method of claim 7, wherein the hydrous mixture comprises product water taken from exhaust gases of a fuel cell system.  A method according to claim 7 or 8, wherein the water-containing liquid is taken from a cooling circuit and / or the windscreen wiper system.  The method of claim 6, wherein the fuel is stored in a refillable liquid hydrogen carrier or in a refillable metal hydride reservoir.

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