WO2004023587A1 - Reformer for a fuel cell system - Google Patents
Reformer for a fuel cell system Download PDFInfo
- Publication number
- WO2004023587A1 WO2004023587A1 PCT/DE2002/003222 DE0203222W WO2004023587A1 WO 2004023587 A1 WO2004023587 A1 WO 2004023587A1 DE 0203222 W DE0203222 W DE 0203222W WO 2004023587 A1 WO2004023587 A1 WO 2004023587A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fuel
- pressure
- piston
- chamber
- line
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- the invention relates to a reformer for a fuel cell system with a fuel supply device which, during operation of the reformer, conveys fuel from a pressurized main fuel line to a reaction chamber.
- Motor vehicles such as passenger cars, commercial vehicles, buses or ships, are used and serve to provide an additional energy source. This is accessed primarily when the motor drive motor, which is normally also used to generate electrical energy, is not in operation. With the help of fuel cell systems, for example, parking heaters or air conditioning systems can be operated while standing, without the capacity of the vehicle battery temporarily restricting the operation of these devices.
- reformers In order to be able to operate a fuel cell with the same fuel as the drive motor of the vehicle, reformers are used which convert the mostly liquid fuel, for example gasoline or diesel, into a hydrogen-containing gas, the so-called reformate. The reformate can then be burned directly in the fuel cell.
- the purpose of the fuel supply devices of reformers is to convey fuel from a tank or from a branch of a fuel line to a reaction chamber of the reformer. In addition, the amount of fuel supplied must be dosed.
- the fuel supply devices can be designed as separate devices or form an integral part of the reformer. The present invention can be used in both embodiments.
- Enclosed accessories are fuel supplies from other brennstoffbetrie- 'in vehicles known.
- a fuel-operated heater in particular a vehicle heater with atmospheric evaporation burner, in which a suction pump designed as a metering pump sucks in fuel through a suction line from a fuel tank and supplies it through a pressure line • the evaporation burner.
- a shut-off valve is arranged in the pressure line immediately upstream of the evaporation burner and prevents the pressure line from steaming empty.
- Suction pumps of this type make it possible to supply fuel to a device with high dosing accuracy.
- a separate suction line must be provided for the suction pump, which leads from the tank or at another suitable point in the remaining unpressurized fuel line system of the motor vehicle to the suction pump.
- the installation of such a suction line is particularly complex when retrofitting a fuel cell system. It is therefore desirable to withdraw the fuel from a main fuel line of the vehicle.
- Fuel is removed for the attachment of a branch of the pressurized main fuel line in the engine compartment is not in the generally used pressurized fuel single-line systems possible because today's designs can promote metering pumps for the supply of accessories only 'at low inlet pressures sufficiently accurate ,
- a metering pump can be installed in such a way that a "high" fuel pressure is present on its inlet side. For example, a pressure of 2 bar is given as the high fuel pressure.
- a pressure of 2 bar is given as the high fuel pressure.
- a reduction in the pressure of the fuel to be introduced into the dosing pump is necessary in these cases.
- a pressure of only 230 mbar is permissible for the metering pump as the inlet pressure.
- the metering pump In order to achieve the required reduction in pressure, the metering pump must be on the inlet side Pressure control valve can be integrated, which reduces the actual fuel pressure to a low value that is suitable for the metering pump.
- the object of the invention is therefore to improve a reformer of the type mentioned at the outset in such a way that a direct connection to a high-pressure fuel line system is made possible.
- the reformer's fuel supply device should be simple and inexpensive.
- a reformer of the type mentioned at the outset which is characterized in that the fuel supply device has at least one chamber into which a fuel line opens with a pre-pressure section for supplying the fuel with the pressure of the main fuel line, and from which a line with a Final pressure section opens out, a metering device having a movable piston being arranged between the pre-pressure section and the final pressure section, and the metering device having on the output side a check valve which has a predetermined minimum opening pressure which is greater than the maximum pre-pressure occurring in the fuel line.
- the basic idea of the invention is that it is imperative for previously known metering pumps that only a very low admission pressure is present on the inlet side, but that a metering device is designed by means of the movable piston. that can, which guarantees a highly precise dosing even with a relatively high inlet pressure on the input side.
- the first chamber formed on the metering device is provided with a check valve, preferably with a spring, by means of which the first chamber is connected to the end pressure section of the fuel line.
- This check valve prevents fuel from escaping from the first chamber. Fuel under pre-pressure can therefore not pass through the metering device on its own, as can occur, for example, in the case of the electromagnetically operated pump according to DE 42 43 866 A1.
- a check valve as described in DE 195 45 677 A1, can be dispensed with in the fuel supply device of a reformer which is further developed according to the invention.
- the check valve is designed such that its opening pressure is slightly above the maximum inlet pressure that occurs in the supply line. This enables the metering device to be arranged directly on the reaction chamber. The metering of the fuel is particularly precise in this case and a particularly space-saving solution has been found. Since the line path of the final pressure section of the fuel line is at the same time relatively short, the reaction chamber can be supplied with fuel again very quickly after the metering device has been switched off.
- the high admission pressure initially has the advantage that the reformer according to the invention can be connected at any point in the fuel line system of the motor vehicle.
- the high upstream pressure also means that the metering device itself is only relatively small
- the metering device of the fuel supply device has a piston which is displaceably mounted in a cylinder in such a way that a first chamber with a variable volume is formed at one end of the piston and which fuel can be supplied under pre-pressure through the pre-pressure section of the fuel line.
- the fuel entering the chamber is conveyed by moving the piston toward the reaction chamber in the end pressure section of the fuel line.
- the pressure of the fuel is further increased, at least slightly.
- the fuel is metered to the reaction chamber in a particularly simple manner. In other words, the fuel is conveyed to the reaction chamber in portions.
- a reformer with the fuel supply device designed according to the invention is relatively inexpensive and also has a lower energy consumption.
- the reformer according to the invention with its fuel supply can be particularly advantageously used when its metering device to an inlet pressure of 2 to 10 bar, in particular from 5 to 8 bar, is • tuned.
- This admission pressure can be provided by a supply line, a return line or a fuel chamber, in which pressure is built up by means of a fuel pump that is internal to the vehicle or that is external to the vehicle.
- the fuel pump does not have to dose the fuel like conventional metering pumps do, but only has to provide the pre-pressure.
- the fuel for the reformer reaction chamber is metered according to the invention by means of the metering device.
- a further developed metering device particularly advantageously has a second chamber at the second end of the piston, which is likewise delimited by the cylinder and the fuel can be supplied under pre-pressure.
- the piston of the metering device is thus loaded at both ends with fuel under pre-pressure, thus establishing a balance of forces on the piston. If the piston is now to be displaced, the driving unit only has to generate the force required
- both the first chamber and the second chamber are connected to the pre-pressure section and to the indentation section, so that when the piston is moved back and forth, fuel is alternately conveyed into the final pressure section.
- the pre-pressure section and / or final pressure section advantageously branch within the metering device in each case into two lines communicating with the respective chambers.
- the reformer according to the invention can also be produced particularly cost-effectively by providing at least one follow-up valve in the fuel supply device, by means of which the first chamber is connected to the pre-pressure section of the fuel line and which is closed by displacing the piston.
- a follow-up valve can be formed in a simple manner by a follow-up opening, ie a radial bore which, when the piston is in the basic position, passes through a wall of the cylinder in front of one end of the piston. If the piston is moved out of its rest position, it runs over the trailing opening and closes it with it. When the piston is moved further, the fuel which is then initially enclosed in the first chamber is pushed out of the latter and fed to the reaction chamber.
- the follow-up valve can be designed as a so-called central valve in the piston itself.
- the piston which is provided in the metering device developed according to the invention, is actuated particularly advantageously by means of a magnet coil.
- This can be supplied with electrical current, which is either predefined over time or which can be changed, taking into account further factors, for example by means of a control unit.
- FIG. 1 shows a schematic illustration of a reformer with a fuel supply device
- Figure 2 shows a first embodiment of a metering device in longitudinal section
- Figure 3 shows a second embodiment of a metering device also in longitudinal section.
- FIG. 1 shows a schematic representation of a reformer 1 for a fuel line system.
- the reformer 1 has a reaction chamber 4 with a mixture formation zone 8 and a reforming zone 5, in which a fuel and an oxidizing gas, for example air, are mixed in order to subsequently react with one another in the reforming zone 5 to form reformate 7.
- the oxidation gas is fed to the reaction chamber 4 via a blower 6 and the fuel through a fuel feed device 9 in a defined amount and under a defined pressure.
- This is shown in the figure as a separate unit, but can also be designed as an integral part of the reformer.
- FIG. 2 shows a more detailed illustration of the fuel supply device 9.
- a metering device 10 encompassed by this and shown in FIG. 2 has a housing block 12 in which a circular-cylindrical cavity 14 is formed, which extends with respect to FIG. 2 along a horizontal axis 16.
- the housing block 12 forms with the cavity 14 a cylinder in which a circular-cylindrical piston 18 is sealingly slidably mounted.
- the piston 18 divides the cavity 14 into a first chamber 20, which is located at the left end of the piston 18 in relation to FIG. 2, and a second chamber 22 which is located at the right end of the piston 18 in relation to FIG.
- a fuel line 24 leads through the metering device 10. This is divided by the first chamber 20 into a pre-pressure section 26 and an end pressure section 28.
- the admission pressure section 26 is formed by a line 26A, which extends radially to the axis 16 through the housing block 12 and opens into the first chamber 20 at a trailing opening 30.
- a pressure relief line 31 leads from said bore through the housing block 12 and opens into the second chamber 22 in the form of a line 28B.
- the end pressure section 28 is designed by means of a line 28A, which likewise extends radially to the axis 16 and in relation to FIG 2 outermost left end region of the cavity 14 leads out of this.
- the pre-pressure section 26 is supplied with fuel under pre-pressure from a chamber (not shown) of a fuel line system of an internal combustion engine. This can be done, for example, by means of a relatively imprecise pump, such as a vibrating piston pump.
- the end pressure section 28 is connected to a reaction chamber (not shown) of a fuel-operated reformer, by means of which reformate for a fuel cell is produced.
- a nonreturn valve 32 is also arranged at the end of the first chamber 20 facing away from the piston 18 and, in the closed state, closes the first chamber 20 in a liquid-tight manner.
- the end pressure section 28 leads out of the cavity 14 with the line 28A.
- the check valve 32 has a valve plate 34 which is pressed by a spring 36 against a valve seat 38.
- the piston 18 is held displaceably by means of a tension spring 40 which is arranged in the second chamber 22 and is fastened to the end wall of the cavity 14.
- the piston 18 is also radially surrounded by a magnetic coil 42, which is embedded in the housing block 12 and by the alternating excitation of the piston 18 can be set into an oscillating movement.
- fuel is present in the admission line 26 under an admission pressure of approx. 8 bar. This fuel also fills the first chamber 20 up to the check valve 32.
- the piston 18 is initially in the position shown in FIG. 2.
- the overflow opening 30 acts like an overflow valve, which allows fuel to flow in only when the piston 18 is at least essentially in its basic position shown in FIG. If the metering device 10 is now put into operation, the piston 18 is displaced along the axis 16 in the direction of the first chamber 20 by means of the magnet coil 42. That of the first chamber 20 turned end of the piston 18 passes over the trailing opening 30, which is thereby closed.
- the pressure of the outflowing fuel is determined by the back pressure of the spring 36 on the check valve 32.
- the amount removed is determined by the stroke of the piston 18 since the fuel is essentially incompressible. If necessary, this stroke can be changed by a corresponding control of the solenoid 42 according to the currently existing form.
- measuring devices can be provided, by means of which the pre-pressure and / or the final pressure is determined.
- the magnet coil 42 is shut down and the piston 18 is pulled back into its basic position by the tension spring 40. In this position, fuel flows under pre-pressure through the trailing opening 30 into the first chamber 20.
- the pre-pressure of the fuel is also present in the second chamber 22.
- the piston 18 is therefore loaded with pre-pressure at both ends, so that the solenoid 42 only generates the force for displacing the piston 18 against the additional pressure building up in the first chamber 18 and against the force of the tension spring 40 got to. It can therefore be designed to be relatively low-power and small.
- the dosage itself is, so to speak, insensitive to pre-pressure.
- Figure 3 shows an embodiment of a metering device 10, in which the piston 18 is designed as a double-acting piston.
- the first chamber 20 and a check valve 32 arranged thereon are formed at one end of the piston 18 in accordance with the exemplary embodiment described above and are connected via a line 26A to the admission pressure section 26 and via a line 28A to the end pressure section 28 of the fuel line 24.
- the second chamber 22 is connected both to the pre-pressure section 26 via a line 26B and to the end pressure section 28 via a line 28B.
- a check valve 32 is arranged in the second chamber 22, which is designed like the check valve 32 on the first chamber 20.
- the lines 28A and 28B leading out of the first and second chambers 20 and 22 are combined in a final pressure section 28 of the fuel line.
- the lines 26A and 26B leading into the first chamber 20 and the second chamber 22 in the metering device 10 are combined in a pre-pressure section 26.
- the connections of the second chamber 22 to the pre-pressure and final pressure sections 26 and 28 of the fuel line 24 are designed according to those on the first chamber 20.
- the connection of the admission pressure section 26 to the second chamber 22 is designed as a follow-up valve by means of a follow-up opening 30.
- the piston 18 is prestressed at both ends by a compression spring 44, which is arranged in the chambers 20 and 22 and is supported on the valve seats 38 of the respective check valves 32.
- the piston 18 is first shifted from the basic position shown in FIG. 3 by means of the magnetic coil 42 in one direction and then in the opposite direction along the axis 16.
- the solenoid 42 has two windings, not shown, which can be controlled separately.
- the piston 18 carries out two strokes, in which fuel is displaced from the first chamber 20 and from the second chamber 22 through the respective check valve 32 under final pressure into the final pressure section 28 and is thus metered to the reaction chamber mentioned. Due to the rapid succession of doses, the metering device 10 according to this exemplary embodiment results in particularly small pressure fluctuations in the final pressure section 28 of the fuel line 24. This leads to a particularly precise quantitative metering of the fuel.
- the check valve or valves 32 perform a double function. On the one hand, they limit or control the final pressure at which fuel is conveyed out of the metering device 10, on the other hand it blocks or they shut off the fuel line 24 while no fuel is being conveyed. Emptying or empty steaming of the fuel line 24 is thereby reliably prevented. The "zero closure" of the fuel line 24 required by reformers is thus ensured.
- a check valve, as described in the reformer ⁇ according to DE 195 45 677 AI, is not required in the exemplary embodiments shown. LIST OF REFERENCE NUMBERS
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Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/DE2002/003222 WO2004023587A1 (en) | 2002-09-02 | 2002-09-02 | Reformer for a fuel cell system |
AU2002325816A AU2002325816A1 (en) | 2002-09-02 | 2002-09-02 | Reformer for a fuel cell system |
DE10297811T DE10297811D2 (en) | 2002-09-02 | 2002-09-02 | Reformer for a fuel cell system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/DE2002/003222 WO2004023587A1 (en) | 2002-09-02 | 2002-09-02 | Reformer for a fuel cell system |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2004023587A1 true WO2004023587A1 (en) | 2004-03-18 |
Family
ID=31954681
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE2002/003222 WO2004023587A1 (en) | 2002-09-02 | 2002-09-02 | Reformer for a fuel cell system |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU2002325816A1 (en) |
DE (1) | DE10297811D2 (en) |
WO (1) | WO2004023587A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3704965A (en) * | 1968-06-07 | 1972-12-05 | Siemens Ag | Valve-controlled differential pump system and method of operation |
WO1999030380A1 (en) * | 1997-12-05 | 1999-06-17 | Elias Elias R | Apparatus for pumping a fluid in a fuel cell system |
WO2001041240A2 (en) * | 1999-11-30 | 2001-06-07 | Vodafone Ag | Fuel cell system |
DE19959851A1 (en) * | 1999-12-10 | 2001-06-21 | Daimler Chrysler Ag | Dual-fuel injector for IC engines of motor vehicles has hydraulic slide to connect either of two fuel supply channels to nozzle outlet |
DE10135625A1 (en) * | 2000-12-15 | 2002-06-20 | Gen Motors Corp | Hydrogen supply system for fuel cell arrangement has hydrogen recirculating pump driven by energy of pressure of hydrogen extracted from tank or coming from reforming unit |
-
2002
- 2002-09-02 WO PCT/DE2002/003222 patent/WO2004023587A1/en not_active Application Discontinuation
- 2002-09-02 AU AU2002325816A patent/AU2002325816A1/en not_active Abandoned
- 2002-09-02 DE DE10297811T patent/DE10297811D2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3704965A (en) * | 1968-06-07 | 1972-12-05 | Siemens Ag | Valve-controlled differential pump system and method of operation |
WO1999030380A1 (en) * | 1997-12-05 | 1999-06-17 | Elias Elias R | Apparatus for pumping a fluid in a fuel cell system |
WO2001041240A2 (en) * | 1999-11-30 | 2001-06-07 | Vodafone Ag | Fuel cell system |
DE19959851A1 (en) * | 1999-12-10 | 2001-06-21 | Daimler Chrysler Ag | Dual-fuel injector for IC engines of motor vehicles has hydraulic slide to connect either of two fuel supply channels to nozzle outlet |
DE10135625A1 (en) * | 2000-12-15 | 2002-06-20 | Gen Motors Corp | Hydrogen supply system for fuel cell arrangement has hydrogen recirculating pump driven by energy of pressure of hydrogen extracted from tank or coming from reforming unit |
Also Published As
Publication number | Publication date |
---|---|
DE10297811D2 (en) | 2005-07-21 |
AU2002325816A1 (en) | 2004-03-29 |
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