DE102007052259A1 - Fuel supply device for proportional supply of hydrogen to consumer, particularly to internal combustion engine of motor vehicle, for burning gaseous fuel in combustion chamber, has hydrogen storage, particularly cryogenic tank - Google Patents

Abstract

The fuel supply device has a hydrogen storage, particularly a cryogenic tank and a pressure increasing device for hydrogen. A heating or cooling medium is a mass flow of an operating material of the consumer, particularly exhaust gas or coolant of the consumer. A part of the mass flow flows through a heat exchanger. A pressure-resistant vessel (4) forms a part of the heat exchanger.

Description

The The invention relates to a fuel supply device for a motor vehicle operable with hydrogen according to the preamble of the first claim, whose hydrogen extraction device a container, in particular from a cryotank, a Sorptionshydridkompressor as pressure booster for gaseous hydrogen.

It It is already known to drive motor vehicles with hydrogen and this fuel, for example, as condensed gas in one Store container in the vehicle. To this liquefied storage special pressure-resistant containers are necessary due to the deep storage temperatures have a very good insulation should. It is known to avoid heat input from the environment, double-walled, vacuum-insulated containers to use.

Of hydrogen can be used in motor vehicles for their operation, also be stored in compressed gas storage tanks or in hydride storage tanks. However, the storage takes place in the form of cryogenic, liquefied Hydrogen, as condensed gas, becomes one for vehicles achieved advantageous high range, since in this state a high energy density is achieved, for example, opposite storage of warm, compressed hydrogen gas.

Of the Deep-frozen, liquid hydrogen is stored in the vehicle in the boiling state in a thermally very well insulated, pressure-tight Container stored. The energy density of the boiling hydrogen becomes little over by storage at a temperature the boiling temperature at ambient pressure, about 20 K, maximum. In the today technically converted storage tanks is the Typically at temperatures of approx. 21 K to approx. 27 K and the corresponding boiling pressures of 2 bar (abs.) to approx. 5 bar (abs.) before.

in the lower part of the reservoir is the boiling hydrogen as a more dense liquid phase (in the following also LH2) and above as gaseous Phase (also called GH2 in the following).

The immediate promotion of hydrogen (will be in the following also called H2) from the reservoir in a flow line, towards a consumer, in the simplest case, over the static pressure gradient between the tank interior and the environment, or by a targeted printing of the reservoir. There is basically the possibility of the geometric design of the feed line beginning in the tank interior, priority to promote LH2 or GH2 only.

stored H2 is generally taken from the gas phase as GH2. Provided H2 is taken as LH2 from the liquid phase, are at a mobile application, the following conditioners, z. B. printer's height, or the mode of a consumer nevertheless for the Promotion of GH2 designed. This is required because due to possible deviations from the normal position of the mobile Container, or dynamic, accelerated states, the inlet opening of a sampling line for LH2 systematically even at high levels of gas phase can be temporarily washed around. This is in the course of time the emptying of the mobile container in particular long possible before the gas phase in one identical immobile container the inlet opening reached the LH2 extraction line by pure removal. For this Reason for mobile applications H2 is mainly from the gas phase taken.

the Reservoir becomes heat during H2 removal fed to the evaporation of LH2 in the container and thus to maintain one for the promotion required container pressure leads, otherwise would decrease by taking so far that a promotion no longer possible. This for pressure maintenance required heat is supplied via a separate heating, the z. B. as an electrically operated heating element may be executed or z. B. directly by supply of heated, gaseous H2, which is a heated Supply flow diverted specifically and in the inner container (back) is conducted.

The aim is the engine in the gaseous fuel State of aggregation at least partially by high pressure injection in the combustion chamber or chambers already containing a compressed gas or to supply combustion chambers for combustion, since This minimizes the risk of flashbacks and the power density and the efficiency of the internal combustion engine can be increased.

to Implementation of such a high pressure injection, the pressure in the stored fuel ultimately be high enough. This high pressure fuel is used for direct injection into the already compressed Gas or air-fuel mixture containing internal combustion engine combustion chambers used, which only works in time as long as a sufficiently large amount of fuel in the pressure tank is available. Is this, however, a certain amount of fuel taken, so falls inevitably the pressure in this pressure tank so far off that a direct fuel injection under high pressure is no longer possible.

thereupon can still contained and only present under reduced pressure Fuel, at least to a certain extent, the internal combustion engine be supplied under low pressure for combustion, in particular under external mixture formation. However, enough in this method of the internal combustion engine available fuel supply is not sufficient for full load operation, the means, from a certain degree, the emptying of the pressure tank Only partial load operation is possible with low load requirements.

The DE 10 2004 062 155 A1 shows a remedy for this described problem and describes a sampling system, at least for the pro rata supply of a gaseous in a combustion chamber fuel consumer with hydrogen, in particular an internal combustion engine of a motor vehicle, at least from a hydrogen storage, in particular a cryotank, and a Sorptionshydridkompressor as pressure increasing device for the Hydrogen, which is connected via a connecting device to the combustion chamber of the consumer. The fuel supply device is characterized in that the pressure-increasing device consists at least of a pressure-resistant vessel containing at least one substance, in particular a hydride-forming metal alloy which cyclically de-absorbs hydrogen with heat or heat removal, and that the pressure booster at least before the Combustion chamber, the pressure of the gaseous hydrogen at least temporarily increased so that the gaseous hydrogen flows into the combustion chamber by utilizing a pressure gradient.

Thereby is essentially the total amount of hydrogen storage for the operation of the internal combustion engine available.

task It is the object of the present invention to provide a pressure increasing device by means of a Sorptionshydridkompressors with high delivery dynamics ready in liquid-operated DC link circuits for heating and cooling with associated further Heat exchangers eliminated. For use in the motor vehicle If the pressure booster should be simple and over the prior art, the operationally necessary Total mass or the operational total volume, the costs and the failure rate can be reduced. Advantageous training and further education are Content of the subclaims.

To The invention consists of a fuel supply device at least for the proportional supply of a gaseous fuel in a combustion chamber burning consumer with hydrogen, especially an internal combustion engine a motor vehicle, at least one hydrogen storage, in particular a cryotank, and a pressure booster for the hydrogen, which has a connecting device connected to the combustion chamber of the consumer and at least in front of the combustion chamber the pressure of the gaseous hydrogen at least temporarily increased so that the gaseous Hydrogen taking advantage of a pressure gradient in the Combustion chamber flows in. For this purpose there is the pressure booster from at least one pressure-resistant vessel, the at least contains a substance, in particular a hydride-forming Metal alloy, by heat removal and hydrogen supply is subjected to hydrogen under a lower gas pressure and by supplying heat to the higher hydrogen Gas pressure is caused, including cyclically changing at least a portion the hydrogen absorbing substance through a heat exchange process is subjected to a higher temperature. The flameproof Vessel forms part of a heat exchanger, whose outer surface is covered by a heating and / or cooling medium can be acted upon. The invention draws characterized in that the heating and / or cooling medium at least a mass flow of a fuel of the consumer, in particular the exhaust gas and / or the coolant, and that at least one Part of this mass flow flows through the heat exchanger.

The has the advantage that the Sorptionshydridkompressor a large Förderdynamik possesses, because with liquid-operated DC link for heating and cooling with associated account for further heat exchangers. Installed directly in the fuel flow the pressure booster is simply constructed and predestined for use in motor vehicles. The operational total mass or the operational total volume, the costs and the failure rate are thereby reduced.

advantageous Training and further developments of the invention provide that the heat exchanger a, the pressure-resistant housing at least partially surrounding, for the heating and / or cooling medium tight housing with at least one inlet and one outlet opening for has the heating and / or cooling medium. So can advantageously The Sorptionshydridkompressor directly into a line one to the Cooling or heating of necessary equipment the internal combustion engine are installed.

If then the pressure increasing device consists of at least two pressure-resistant vessels, which are connected in series and / or parallel to increase the pressure of the gaseous hydrogen gradually and / or delayed, at least one heat exchanger can alternatively be acted upon with the heating medium or with the cooling medium , if in the flow area depending on a connecting line for the heating and Cooling medium zulauföffnungsseitig a control valve is present, which releases the inflow of a medium substantially, while the inflow of the other medium is substantially blocked.

So are advantageously required for operation only control flaps and the function of the Sorptionshydridkompressors is by the connection the two operating phases, heating and cooling, to simple Guaranteed manner without control valves or control valves, whereby the operationally necessary total mass or the operationally necessary Total volume of Sorptionshydridkompressors and reduced its cost become.

If several heat exchangers in parallel over at least one connecting line each from the heating and / or cooling medium, in particular exhaust gas, are acted upon, wherein the connecting lines after the drain opening in a common drain line flow out into the area downstream and a sufficiently large flow area has, so that in the drain line approximately ambient pressure is present, the Sorptionshydridkomperssor has a particularly large flow dynamics and in a simple way can be determined by the frequency of the circuit Control flaps a desired operating point for the sorption hydride compressors are adapted. It will also be a Backflow prevented.

at a preferred embodiment of the invention consists of Pressure increasing device of at least two pressure-resistant Vessels of which during operation the pressure booster first always the higher Has temperature and the hydrogen de- and absorbent, under operating temperature eligible substance alternately takes a position in the first or in the second pressure-resistant vessel.

The has the advantage of supplying the consumer with gas through allows continuous Sorpionshydridkompressore operation what will be a further reduction in mass and volume of the Sorpionshydridkompressors allowed. Additionally omitted the control flaps when the heat exchanger of the first pressure-resistant Vessel continuously with the heating medium, in particular with Exhaust gas and the heat exchanger of the second pressure-resistant vessel continuously with the cooling medium, in particular with cooling water or forced air is applied.

So can be gaseous and liquid heat-conducting Media that is present in the vehicle and does not mix may, like exhaust and cooling water, at the same time use. The heat requirement of the sorption hydride compressor is reduced by the continuous operation. Proceeding This is done by another heat exchanger in or between the internal hydride-carrying lines of the Sorptionshydridkompressors allows.

To is in further preferred embodiments of the invention in at least one of two connecting lines between the first and second pressure-resistant vessel through which the substance circulated, at least one further heat exchanger integrated, transferred with the heat from or in at least one of the two connecting lines can be. This additional heat exchanger can also be common heat exchanger between the two connecting lines be, in particular, a countercurrent heat exchanger.

additional preferred embodiments of the invention are characterized that the pressure increasing means from the hydrogen storage via another connecting line is supplied with hydrogen and that this further connection line with the connection device, between Pressure Booster and consumer, by a common additional heat exchanger, in particular also by a countercurrent heat exchanger, thermal connected is. In particular, if in the connection device, between the additional heat exchanger and the Pressure Booster another additional Heat exchanger, in particular a fan cooler, with the heat from the extracted hydrogen can be dissipated, installed, burdened use the sorption hydride compressor to promote cryogenic Hydrogen in the combustion chamber of the internal combustion engine practically not their exergetic total balance, since the hydraulic conveying work the Sorptionshydridkompresssors from anergetic waste heat can be won.

in the The invention will be described below with reference to two preferred embodiments further explained. Show it:

1 FIG. 2 is a schematic representation of an arrangement of sorption hydride compressors in an exhaust system as a pressure-increasing device for stored hydrogen for operating an internal combustion engine, and FIG

2 in a schematic representation of an arrangement of a Sorptionshydridkompressors in a cooling water or exhaust pipe as a pressure increasing device for cryogenically stored hydrogen for operating an internal combustion engine.

In a not shown motor vehicle, a hydrogen storage, in particular a not shown cryogenic tank, installed for the storage of liquid hydrogen. The hydrogen serves as Fuel for at least proportionate supply of a motor vehicle driving, not shown, internal combustion engine as a consumer. A not shown extraction device for gaseous hydrogen from the hydrogen storage powered via a sampling line, the engine with hydrogen.

For printing and conveying the gaseous hydrogen, the sampling line leads to an in 1 drawn pressure booster, in addition to Sorptionshydridkompressoren 1 . 2 . 3 used. On the output side, with its pressure side, these are connected via a not-shown connection means to the combustion chamber of the internal combustion engine. Alternatively or in addition to the internal combustion engine, however, not shown fuel cells could be supplied with hydrogen. The pressure booster consists of three Sorptionshydridkompressoren 1 . 2 . 3 with pressure-resistant vessels 4 , Which are connected in parallel and which increase the pressure of the gaseous hydrogen in each case with a time delay in order to always ensure approximately the same pressure level in the connecting device can. These include the pressure-resistant vessels 4 in each case a hydride-forming metal alloy, the sorption hydride, which is acted upon by heat removal and hydrogen supply under a lower gas pressure with hydrogen and caused by supplying heat to the hydrogen release under higher gas pressure. In order to cyclically change the sorption hydride by a heat exchange process with a higher temperature, forms the pressure-resistant vessel 4 a part of a heat exchanger whose outer surface can be acted upon by a heating or cooling medium. These are the heat exchangers of Sorptionshydridkompressoren 1 . 2 . 3 each with its inlet opening 8th to each one heating or cooling medium leading connection line 5 connected, with the connecting cables 5 downstream of the sorption hydride compressors 1 . 2 . 3 with their drainage holes 6 in a common drain line 7 open, which leads further downstream into the environment and has such a large flow cross-section that in the drain line 7 Approximately ambient pressure is applied.

The sorption hydride compressors 1 . 2 . 3 are thus integrated in pipes suitable for the supply and removal of heat streams, that the mass flows in the pipes heat exchangers of Sorptionshydridkompressoren 1 . 2 . 3 flow through. Thus, each heat exchanger has one, the pressure-resistant vessel 4 at least partially surrounding, for the heating or cooling medium tight housing 9 with the 8th and drain opening 6 for the heating or cooling medium. The to operate the Sorptionshydridkompressoren 1 . 2 . 3 required operating heat flows can be generated or provided in any way. However, a mass flow of an operating fluid of the consumer, in particular its exhaust gas and / or its coolant, is advantageous. Here is the heat supply waste heat from the exhaust stream 10 the internal combustion engine used. Equally, however, by cooling the internal combustion engine heated cooling water could be used for heat. The sorption hydride compressors 1 . 2 . 3 would then be installed accordingly in the cooling water pipes of the engine cooling.

As a cooling medium here is a fan air flow 11 used to provide it in the exhaust system 12 a fan air duct 13 is integrated. The heat exchangers are alternatively with the exhaust gas 10 or with the forced air 11 acted upon by in the flow area of each connecting cable 5 a hinged control flap 14 present is the inlet opening 8th either for the inflow of exhaust gas 10 or by forced air 11 releases. At the same time, the inflow of the other medium is essentially blocked. For heat supply and removal, however, could also be used according to the cooling system of the internal combustion engine, each with the hot or cold cooling water flow.

2 shows a further embodiment of a pressure increasing device with a Sorptionshydridkompressor 1 which has a sorption bed in which two temperatures and two pressures prevail. From two pressure-resistant vessels 4 . 4 ' of the sorption hydride compressor 1 has during operation of the pressure booster a first, the hot part, always the higher temperature, the hydrogen de- and absorbent, under operating temperature eligible, continuously or quasi-continuously changing substance occupies a position in the first or in the second pressure-resistant vessel, the cold part. During operation, there are always the same conditions for the sorption hydride in terms of temperature and pressure, desorption conditions in the hot part or absorption conditions in the cold part.

The two pressure-resistant vessels 4 . 4 ' are over two pipelines 19 . 20 connected, in which a control valve or a shut-off device 18 , a throttle 21 and a pressure-increasing conveyor, in particular a pump 17 , or a one-way shut-off device is located. There is also another heat exchanger 16 acting as a common heat exchanger between the two connecting lines 19 . 20 by heat transfer for a temperature compensation, installed.

The pipelines 19 . 20 with the arranged facilities 16 . 17 . 18 . 21 are designed to promote the sorption used suitably. The liquid sorption hydride is in Constant or time-varying proportions at any time both in the hot part, as well as in the cold part and a small part in the aforementioned pipelines 19 . 20 , In the hot part, the sorbent contained therein is continuously discharged from the hydrogen and the discharged hydrogen discharged under desorption pressure to the outside. In the cold part, the sorbent contained therein is continuously charged with hydrogen and the absorbed hydrogen fed with absorption pressure from the outside.

So that these two simultaneous processes do not come to a standstill, the liquid Sorptionshydrid between hot and cold section is continuously on the pipelines 19 . 20 from the pump 17 between both pressure-resistant vessels 4 . 4 ' circulated. In this case, the hydrogen-reduced sorption hydride from the hot part preferably passes through the use of the pressure gradient to the cold part. From the cold part, the hydrogen-loaded sorption hydride passes through the pump 17 It raises it to desorption pressure level again into the hot part. Different modes of operation are possible. The sorption hydride can be circulated in a constant or quasi-constant mass flow, but this can also be dependent on any state variables or input variables in the sorption hydride compressor 1 or in the supplied hydrogen consumer or in the motor vehicle.

Hot part and cold part are designed in their spatial arrangement and orientation so that both on the one hand allow the supply and removal of hydrogen and the circulation of the sorption, on the other hand, an excellent heat exchange function is ensured with a fuel of the internal combustion engine. These are the hot part and the cold part of the sorption hydride compressor 1 integrated in the supply lines for the supply and the removal of heat streams suitable fuel lines, so that the mass flows in the lines, the heat exchanger of the Sorptionshydridkompressors 1 flow through. Thus, each heat exchanger has one, the pressure-resistant vessel 4 . 4 ' at least partially surrounding, for the heating or cooling medium tight housing 9 with at least one 8th and a drain opening 6 for the heating or cooling medium. The to operate the Sorptionshydridkompressors 1 required operating heat flows can be generated or provided in any way. Here, for the hot part, a mass flow of the engine exhaust gas 10 and for the cold part, a mass flow of the engine cooling water 22 used. This is the hot part in the exhaust system 12 and the cold part in a cooling water line 23 built-in. The heat exchanger of the first pressure-resistant vessel 4 It will be so continuous with exhaust 10 , the heat exchanger of the second pressure-resistant vessel 4 ' continuously with cooling water 22 applied.

At any time during operation are in the two pressure-resistant vessels 4 . 4 ' of the sorption hydride compressor 1 locally approximately constant overall both pressures associated with the sorption cycle and the corresponding temperatures. Therefore, for the cyclic heating and cooling of Sorptiopnshydrids essentially only the heat flows needed for the desorption or

Asorption of the sorbent itself are required. For the adaptation of the temperature of the housing structure systematically no heat flows are needed. For the cyclic adaptation of the temperature of the circulating promoted Sorptionshydrids only very small heat flows are needed because its heat in the other heat exchanger 16 is transmitted.

The fuel supply of the internal combustion engine with hydrogen via the pressure booster is effected by the removal of the cryogenically stored hydrogen from the cryotank 30 with a pressure of for example 2 bar via another connecting line 31 into the cold part of the Sorpionshydridkompressors 1 , There, the hydrogen is absorbed by the sorption and after its transition into the hot part with increased pressure from the sorption in the connecting device 33 discharged to the internal combustion engine, so that the gaseous hydrogen by utilizing a pressure gradient with a pressure of, for example, 15 bar in the combustion chamber 32 flows. The connection device 33 is with the further connection line 31 through a common, additional heat exchanger 34 thermally connected and in the connection device 33 , between the additional heat exchanger 34 and the hot part, is another additional heat exchanger, a blower cooler 35 , built-in, with the heat from the pumped hydrogen, for example, in the environment, can be dissipated.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102004062155 A1 [0012]

Claims (12)

Fuel supply device at least for the proportionate supply of a consumer burning in a combustion chamber gaseous fuel with hydrogen, in particular an internal combustion engine of a motor vehicle, at least consisting of a hydrogen storage, in particular a cryogenic tank ( 30 ), and a pressure booster for the hydrogen, which via a connecting device ( 33 ) with the combustion chamber ( 32 ) of the consumer and at least before the combustion chamber ( 32 ) the pressure of the gaseous hydrogen at least temporarily increased so that the gaseous hydrogen by utilizing a pressure gradient in the combustion chamber ( 32 ), for which purpose the pressure-increasing device consists of at least one pressure-resistant vessel ( 4 . 4 ' ), which contains at least one substance, in particular a hydride-forming metal alloy, which is acted upon by heat removal and hydrogen supply under a lower gas pressure with hydrogen and is caused by heat supply to the hydrogen release under higher gas pressure, including cyclically changing at least a portion of the hydrogen absorbing material through a Heat exchange process is subjected to a higher temperature, the pressure-resistant vessel ( 4 . 4 ' ) forms part of a heat exchanger whose outer surface can be acted upon by a heating and / or cooling medium, characterized in that the heating and / or cooling medium at least one mass flow of a fuel of the consumer, in particular its exhaust gas ( 11 ) and / or its coolant ( 22 ), and that at least part of this mass flow flows through the heat exchanger. Fuel supply device according to claim 1, characterized in that the heat exchanger, the pressure-resistant vessel ( 4 . 4 ' ) at least partially surrounding, for the heating and / or cooling medium tight housing ( 9 ) with at least one additional 8th ) and a drain opening ( 6 ) has for the heating and / or cooling medium. Fuel supply device according to claim 1 or 2, characterized in that the pressure increasing device of at least two pressure-resistant vessels ( 4 . 4 ' ), which are connected in series and / or in parallel to increase the pressure of the gaseous hydrogen gradually and / or with a time delay. Fuel supply device according to one of claims 1 to 3, characterized in that at least one heat exchanger can be acted upon alternatively with the heating medium or with the cooling medium by in the flow region per a connecting line ( 5 ) for the heating and cooling medium zulauföffnungsseitig a control valve ( 14 ), which substantially releases the inflow of one medium while substantially blocking the inflow of the other medium. Fuel supply device according to one of claims 1 to 4, characterized in that a plurality of heat exchangers in parallel via at least one respective connecting line ( 5 ) from the heating and / or cooling medium, in particular exhaust gas ( 10 ), the connecting lines ( 5 ) after its expiration ( 6 ) into a common drain line ( 7 ), which leads downstream into the environment and has a sufficiently large flow cross-section, so that in the drain line ( 7 ) Approximately ambient pressure is applied. Fuel supply device according to claim 1 or 2, characterized in that the pressure increasing device of at least two pressure-resistant vessels ( 4 . 4 ' ), of which during operation of the pressure increasing device a first ( 4 ) always has the higher temperature and that at least the hydrogen decarburizing and absorbing substance, which can be used under operating temperature, alternately assumes a position in the first ( 4 ) or in the second ( 4 ' ) occupies pressure-resistant vessel. Fuel supply device according to claim 6, characterized in that the heat exchanger of the first pressure-resistant vessel ( 4 ) continuously with the heating medium, in particular with exhaust gas ( 11 ) is applied. Fuel supply device according to claim 6 or 7, characterized in that the heat exchanger of the second pressure-resistant vessel ( 4 ' ) continuously with the cooling medium, in particular with cooling water ( 22 ) or forced air is applied. Fuel supply device according to one of claims 6 to 8, characterized in that in at least one of two connecting lines ( 19 . 20 ) between the first ( 4 ) and second ( 4 ' ) pressure-resistant vessel, through which the substance circulates, at least one further heat exchanger, in particular a countercurrent heat exchanger, is integrated, with the heat from or into at least one of the two connecting lines ( 19 . 20 ) can be transmitted. Fuel supply device according to one of claims 6 to 9, characterized in that at least one further heat exchanger, a common heat exchanger ( 16 ) between the two connecting lines ( 19 . 20 ). Fuel supply device according to one of claims 1 to 10, characterized in that the pressure increasing device is removed from the hydrogen storage via a further connecting line ( 31 ) is supplied with hydrogen and that this further connection line ( 31 ) with the connection device ( 33 ) by a common additional heat exchanger ( 34 ), in particular a countercurrent heat exchanger, is thermally connected. Fuel supply device according to claim 11, characterized in that in the connecting device ( 33 ), between the additional heat exchanger ( 34 ) and the second pressure-resistant vessel ( 4 ' ) a further additional heat exchanger is installed, in particular a blower cooler ( 35 ), with which heat can be removed from the pumped hydrogen.