WO2008049444A1 - Gas flow control system - Google Patents

Gas flow control system Download PDF

Info

Publication number
WO2008049444A1
WO2008049444A1 PCT/EP2006/010269 EP2006010269W WO2008049444A1 WO 2008049444 A1 WO2008049444 A1 WO 2008049444A1 EP 2006010269 W EP2006010269 W EP 2006010269W WO 2008049444 A1 WO2008049444 A1 WO 2008049444A1
Authority
WO
WIPO (PCT)
Prior art keywords
passage
fuel cell
exhaust
gas
flow
Prior art date
Application number
PCT/EP2006/010269
Other languages
French (fr)
Inventor
Paul Paterson
Curtis Robin
Original Assignee
Daimler Ag
Ford Global Technologies, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daimler Ag, Ford Global Technologies, Llc filed Critical Daimler Ag
Priority to PCT/EP2006/010269 priority Critical patent/WO2008049444A1/en
Publication of WO2008049444A1 publication Critical patent/WO2008049444A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
    • F02C6/04—Gas-turbine plants providing heated or pressurised working fluid for other apparatus, e.g. without mechanical power output
    • F02C6/10—Gas-turbine plants providing heated or pressurised working fluid for other apparatus, e.g. without mechanical power output supplying working fluid to a user, e.g. a chemical process, which returns working fluid to a turbine of the plant
    • 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
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
    • 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
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04111—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants using a compressor turbine assembly
    • 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
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04291—Arrangements for managing water in solid electrolyte fuel cell systems
    • 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 present invention relates to a gas flow control system and, particularly, but not exclusively, to an arrangement for controlling air flow through the cathode side of a fuel cell.
  • a known type of fuel cell utilises a polymer electrolyte membrane having an anode side over which a stream of fuel gas, such as hydrogen, is passed, and a cathode side over which a stream of oxidant, typically air, is passed.
  • fuel gas such as hydrogen
  • cathode side over which a stream of oxidant, typically air, is passed.
  • hydrogen ions migrate through the membrane to react with the oxygen on the cathode side thereby creating electricity for the load and a process product, water.
  • the two streams of gas which are separate, are maintained at a predetermined pressure and humidity for efficient operation of the fuel cell.
  • the humidity is also necessary to ensure that the membrane does not dry out which would not only reduce its efficiency but can cause damage and a reduction in service life.
  • the present invention seeks to provide an improved gas control system with improved efficiency.
  • a gas flow control system for a fuel cell arrangement having an inlet passage and an exhaust passage, including in the inlet passage in the direction of flow, successively, first compressor means, an intercooler for cooling the gas flow, second compressor means, and an aftercooler for cooling the gas flow exiting the second compressor means, characterized in that a bypass passage leads from the inlet passage at a point where the gas is compressed to the exhaust passage bypassing the fuel cell, the flow of gas through the bypass passage being controlled by valve means.
  • the second compressor means comprises a turbocharger driven by the exhaust gas
  • the bypass passage is connected between the outlet of the compressor of the turbocharger and the inlet to the exhaust driven turbine of the turbocharger.
  • the bypass passage leads from a point in the inlet passage between the first compressor means and the intercooler to the exhaust passage.
  • the valve means comprises a bypass valve located in the bypass passage and the valve is controlled in dependence upon the pressure in the air stream passing through the fuel cell. When the pressure reaches a predetermined maximum, the bypass valve is opened so that the compressed air in the inlet passage is vented directly to the exhaust, bypassing the fuel cell.
  • control system controls the flow of air through a cathode side of a fuel cell stack.
  • Figure 1 shows a first embodiment of an air control system according to the invention
  • Figure 2 shows an air control system in accordance with a second embodiment of the present invention.
  • FIG. 1 there is shown, in schematic form, flow passages and related control system for supplying compressed air to a fuel cell stack 1 and venting excess air to atmosphere.
  • the system has an inlet passage 2 having, successively in the direction of air flow to the fuel cell stack 1, an air intake 3 with a filter 4, an intake air muffler 5, a first compressor 6, an intercooler 7, a second compressor 8, and an aftercooler 9 from where the compressed and cooled air is passed to the inlet 10 of the fuel cell stack 1.
  • the fuel cell stack consists of a number of fuel cells assembled in series and/or in parallel to give the required output.
  • the first compressor 6 comprises a mechanically driven screw compressor driven by the vehicle engine (not shown) .
  • the second compressor 8 comprises a turbo-charger having its compressor 11 in the input passage 2 and a drive turbine 12 driven by the exhaust stream passing through the exhaust passage 13 from the fuel cell stack 1.
  • the exhaust passage 13 from the fuel cell stack passes through the drive turbine 12 of the turbocharger to a silencer 14 from where it is vented to atmosphere.
  • a bypass passage 15 extends from the inlet passage 2 downstream of the second compressor 8 into the exhaust passage 13 just upstream of the drive turbine 12 of the turbocharger.
  • the flow of air from the inlet passage 2 to the exhaust passage 13 through the bypass passage 15 is controlled by an air bypass valve 16, which is in the form of a butterfly valve.
  • the air bypass valve 16 In operation, when the pressure of the air passing through the fuel cell stack 1 reaches a predetermined maximum value, the air bypass valve 16 is opened so that compressed intake air is passed to directly to the exhaust passage 13 just upstream of the drive turbine 12 of the turbocharger, thus bypassing the fuel cell stack 1.
  • bypass passage 15 extends from a point 17 on the inlet passage 2 downstream of the first compressor 6 to a point 18 in the exhaust passage 13 downstream of the drive turbine 12 of the turbocharger .
  • the arrangement shown in Figure 2 has a number of advantages. Firstly, a smaller bypass valve can be used compared with the arrangement shown in Figure 1 because the pressure drop across the valve is higher. Also, since the excess mass flow and pressure is drawn off before the intercooler 7, the load on the cooling system is reduced. Furthermore, because hot, substantially dry, air is being injected into the exhaust stream, the tendency for the water vapour in the exhaust air to condense in the end of the exhaust passage or at its exit is reduced.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Electrochemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel Cell (AREA)

Abstract

A gas flow control arrangement for a fuel cell arrangement having an inlet passage (2 ) and an exhaust passage (13), the arrangement including in the inlet passage ( 2) in the direction of flow, successively, first compressor means (6), an intercooler ( 7) for cooling the gas flow, second compressor means (8), and an af tercooler ( 9) for cooling the gas flow exiting the second compressor means (8). A bypass passage (15) leads from a point in the inlet passage where the gas is compressed to the exhaust passage (13) bypassing the fuel cell (1). A valve (16) is controlling the flow of gas through the bypass passage (15).

Description

Gas Flow Control System
The present invention relates to a gas flow control system and, particularly, but not exclusively, to an arrangement for controlling air flow through the cathode side of a fuel cell.
A known type of fuel cell utilises a polymer electrolyte membrane having an anode side over which a stream of fuel gas, such as hydrogen, is passed, and a cathode side over which a stream of oxidant, typically air, is passed. When an electric load is connected between the anode and cathode of the fuel cell hydrogen ions migrate through the membrane to react with the oxygen on the cathode side thereby creating electricity for the load and a process product, water. The two streams of gas, which are separate, are maintained at a predetermined pressure and humidity for efficient operation of the fuel cell. The humidity is also necessary to ensure that the membrane does not dry out which would not only reduce its efficiency but can cause damage and a reduction in service life. It is also necessary to maintain a predetermined flow of the gases through the fuel cell to ensure that a sufficient quantity of hydrogen and oxygen are passed over the membrane for the electrochemical reaction to be at its most efficient and to ensure that the amount of water and water vapour passing through the fuel cell is at a sufficient level to ensure that the membrane does not dry out but not so large as to block the flow of hydrogen and oxygen over the membrane and thereby reducing the efficiency of the fuel cell.
Under static conditions, the pressure and flow rate of the gases through the fuel cell is easily controlled, but is much more difficult under transient conditions, particularly the rapidly changing load requirements imposed on the fuel cell in automotive applications. When the electric load being drawn from the fuel cell increases, the flow of hydrogen through the fuel cell also increases and, similarly, when the load reduces, the flow of hydrogen reduces. As the hydrogen flow changes, so it is necessary to control the flow of air through the fuel cell to maintain the appropriate gas flow and pressure balance between the two streams .
In automotive applications, not only does the load change rapidly which requires a rapid response from the fuel cell control systems, but the load drawn varies from a minimum when operating under idle conditions up to a maximum for high-speed operation. It is therefore necessary for the air control system to have compressor means which is sufficient to generate the required pressure and mass flow for maximum output. However, under low load conditions the compressor means generates an excessive amount of pressure and mass flow and, to solve this problem, it is known to vent the excess pressure directly to atmosphere. Thus, under a large proportion of the fuel cell operating time, that is, under low and medium load conditions, a proportion of the energy- used to drive the compressor means is wasted, which reduces the overall efficiency of the fuel cell. Additionally, venting the excess directly to atmosphere causes unnecessary noise .
The present invention seeks to provide an improved gas control system with improved efficiency.
According to the present invention that is provided a gas flow control system for a fuel cell arrangement having an inlet passage and an exhaust passage, including in the inlet passage in the direction of flow, successively, first compressor means, an intercooler for cooling the gas flow, second compressor means, and an aftercooler for cooling the gas flow exiting the second compressor means, characterized in that a bypass passage leads from the inlet passage at a point where the gas is compressed to the exhaust passage bypassing the fuel cell, the flow of gas through the bypass passage being controlled by valve means.
In one embodiment of the invention, the second compressor means comprises a turbocharger driven by the exhaust gas, and the bypass passage is connected between the outlet of the compressor of the turbocharger and the inlet to the exhaust driven turbine of the turbocharger. In another embodiment of the invention, the bypass passage leads from a point in the inlet passage between the first compressor means and the intercooler to the exhaust passage. Preferably, the valve means comprises a bypass valve located in the bypass passage and the valve is controlled in dependence upon the pressure in the air stream passing through the fuel cell. When the pressure reaches a predetermined maximum, the bypass valve is opened so that the compressed air in the inlet passage is vented directly to the exhaust, bypassing the fuel cell.
In a preferred embodiment, the control system controls the flow of air through a cathode side of a fuel cell stack.
A preferred embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:
Figure 1 shows a first embodiment of an air control system according to the invention, and
Figure 2 shows an air control system in accordance with a second embodiment of the present invention.
Referring now to Figure 1, there is shown, in schematic form, flow passages and related control system for supplying compressed air to a fuel cell stack 1 and venting excess air to atmosphere. The system has an inlet passage 2 having, successively in the direction of air flow to the fuel cell stack 1, an air intake 3 with a filter 4, an intake air muffler 5, a first compressor 6, an intercooler 7, a second compressor 8, and an aftercooler 9 from where the compressed and cooled air is passed to the inlet 10 of the fuel cell stack 1. The fuel cell stack consists of a number of fuel cells assembled in series and/or in parallel to give the required output. The first compressor 6 comprises a mechanically driven screw compressor driven by the vehicle engine (not shown) . Thus, the output of the first compressor 6 is directly proportional to the speed of the vehicle engine. The second compressor 8 comprises a turbo-charger having its compressor 11 in the input passage 2 and a drive turbine 12 driven by the exhaust stream passing through the exhaust passage 13 from the fuel cell stack 1.
The exhaust passage 13 from the fuel cell stack passes through the drive turbine 12 of the turbocharger to a silencer 14 from where it is vented to atmosphere. A bypass passage 15 extends from the inlet passage 2 downstream of the second compressor 8 into the exhaust passage 13 just upstream of the drive turbine 12 of the turbocharger. The flow of air from the inlet passage 2 to the exhaust passage 13 through the bypass passage 15 is controlled by an air bypass valve 16, which is in the form of a butterfly valve.
In operation, when the pressure of the air passing through the fuel cell stack 1 reaches a predetermined maximum value, the air bypass valve 16 is opened so that compressed intake air is passed to directly to the exhaust passage 13 just upstream of the drive turbine 12 of the turbocharger, thus bypassing the fuel cell stack 1.
Referring now to Figure 2, there is shown an alternative control system in which like parts have like reference numerals. In this embodiment the bypass passage 15 extends from a point 17 on the inlet passage 2 downstream of the first compressor 6 to a point 18 in the exhaust passage 13 downstream of the drive turbine 12 of the turbocharger .
The arrangement shown in Figure 2 has a number of advantages. Firstly, a smaller bypass valve can be used compared with the arrangement shown in Figure 1 because the pressure drop across the valve is higher. Also, since the excess mass flow and pressure is drawn off before the intercooler 7, the load on the cooling system is reduced. Furthermore, because hot, substantially dry, air is being injected into the exhaust stream, the tendency for the water vapour in the exhaust air to condense in the end of the exhaust passage or at its exit is reduced.

Claims

1. A gas flow control arrangement for a fuel cell having an inlet passage (2) and an exhaust passage (13) , the arrangement including in the inlet passage (2) in the direction of flow, successively, first compressor means (6) , an intercooler (7) for cooling the gas flow, second compressor means (8) , and an aftercooler (9) for cooling the gas flow exiting the second compressor means (8) , characterized in that a bypass passage (15) leads from the inlet passage at a point when the gas is compressed to the exhaust passage (13) bypassing the fuel cell (1), and the flow of gas through the bypass passage (15) is controlled by valve means (16) .
2. An arrangement according to claim 1, characterised in that the valve means comprises a bypass valve (16) located in the bypass passage (15) and the valve is controlled in dependence upon the pressure in the air stream passing through the fuel cell, so that when the pressure reaches a predetermined maximum, the bypass valve (16) is opened to enable the compressed air in the inlet passage (2) to be vented directly to the exhaust passage (13) , bypassing the fuel cell.
3. An arrangement according to claim 1 or 2 , characterised in that the second compressor means (8) comprises a turbocharger having a drive turbine (12) driven by the exhaust gas in the exhaust passage and the bypass passage (15) is connected between the outlet of the compressor of the turbocharger (8) and the inlet to the exhaust driven turbine (12) of the turbocharger.
4. An arrangement according to claim 1 or 2, characterised in that the bypass passage (15) leads from a point (17) in the inlet passage (2) between the first compressor means (6) and the intercooler (7) to the exhaust passage (13) .
5. An arrangement according to claim 4, characterised in that the bypass passage (15) leads to a point (18) in the exhaust passage downstream of the turbine (12) of the turbocharger .
6. A gas flow control arrangement according to claim 1, adapted to control the flow of air through a cathode side of a fuel cell stack.
PCT/EP2006/010269 2006-10-25 2006-10-25 Gas flow control system WO2008049444A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2006/010269 WO2008049444A1 (en) 2006-10-25 2006-10-25 Gas flow control system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2006/010269 WO2008049444A1 (en) 2006-10-25 2006-10-25 Gas flow control system

Publications (1)

Publication Number Publication Date
WO2008049444A1 true WO2008049444A1 (en) 2008-05-02

Family

ID=37685719

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2006/010269 WO2008049444A1 (en) 2006-10-25 2006-10-25 Gas flow control system

Country Status (1)

Country Link
WO (1) WO2008049444A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018116855A (en) * 2017-01-19 2018-07-26 トヨタ自動車株式会社 Fuel cell system
JP2019079606A (en) * 2017-10-20 2019-05-23 トヨタ自動車株式会社 Fuel cell system and control method of fuel cell system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4685287A (en) * 1985-11-20 1987-08-11 Mitsubishi Denki Kabushiki Kaisha Compressor system and start-up method therefor
JPS6448378A (en) * 1987-08-17 1989-02-22 Toshiba Corp Control system for fuel cell air supply system
EP0400701A1 (en) * 1989-05-29 1990-12-05 Turboconsult B.V. Method and installation for generating electrical energy
WO2002086997A2 (en) * 2001-04-22 2002-10-31 Daimlerchrysler Ag Fuel cell air supply
DE10216953A1 (en) * 2002-04-17 2003-11-13 Daimler Chrysler Ag Device for supplying fuel cell with process air has motor-driven compression machine arranged after expansion machine on outlet air side on common shaft with compression machine on feed side
DE10322296A1 (en) * 2003-05-17 2004-12-02 Daimlerchrysler Ag Air supply unit for a fuel cell system for a heavy truck braking unit has a turbine driven compressor and a combustion engine on the downstream side of the turbine

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4685287A (en) * 1985-11-20 1987-08-11 Mitsubishi Denki Kabushiki Kaisha Compressor system and start-up method therefor
JPS6448378A (en) * 1987-08-17 1989-02-22 Toshiba Corp Control system for fuel cell air supply system
US5319925A (en) * 1989-05-28 1994-06-14 A.S.A. B.V. Installation for generating electrical energy
EP0400701A1 (en) * 1989-05-29 1990-12-05 Turboconsult B.V. Method and installation for generating electrical energy
WO2002086997A2 (en) * 2001-04-22 2002-10-31 Daimlerchrysler Ag Fuel cell air supply
DE10216953A1 (en) * 2002-04-17 2003-11-13 Daimler Chrysler Ag Device for supplying fuel cell with process air has motor-driven compression machine arranged after expansion machine on outlet air side on common shaft with compression machine on feed side
DE10322296A1 (en) * 2003-05-17 2004-12-02 Daimlerchrysler Ag Air supply unit for a fuel cell system for a heavy truck braking unit has a turbine driven compressor and a combustion engine on the downstream side of the turbine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018116855A (en) * 2017-01-19 2018-07-26 トヨタ自動車株式会社 Fuel cell system
JP2019079606A (en) * 2017-10-20 2019-05-23 トヨタ自動車株式会社 Fuel cell system and control method of fuel cell system

Similar Documents

Publication Publication Date Title
US7297427B2 (en) Fuel cell system and process for controlling the same
US6694735B2 (en) Internal combustion engine with an exhaust turbocharger and an exhaust-gas recirculation device
US6922996B2 (en) Method for controlling an electrically driven compressor
US5611202A (en) Turbocharged internal combustion engine
CN102187068B (en) Exhaust purifying device for internal combustion engine with supercharger
US7399543B2 (en) Fuel cell system for scavenging signal pressure line for regulator
US8232018B2 (en) Anode flowshifting with closed-injector bleeding
US20110097632A1 (en) Air supply unit for a fuel cell stack, fuel cell system and method for operating an air supply unit
CN101842565A (en) The internal-combustion engine that has exhaust-gas turbocharger and charger-air cooler
US8099948B2 (en) Exhaust system of internal combustion engine
CN113571747B (en) Fuel cell air system control method
WO2010041545A1 (en) Engine
US20100159360A1 (en) Arangement and method for providing a fuel cell with an oxidizing agent
US7771883B2 (en) Virtual compressor operational parameter measurement and surge detection in a fuel cell system
CN113764700A (en) Fuel-electric system, control method of fuel-electric system and vehicle
CN102301105B (en) Method and apparatus for controlling turbine efficiency
CN111769305A (en) Fuel cell system with compressor working point and dynamic response capability taken into consideration
WO2008049444A1 (en) Gas flow control system
GB2555504A (en) A boosted engine system of a motor vehicle
US20070267002A1 (en) Internal Combustion Engine with Exhaust Gas Recirculation Device, and Associated Method
CN114759229B (en) Fuel cell control system
JP2012233412A (en) Compressed air supply method for internal combustion engine and internal combustion engine
CN111883801A (en) Fuel cell air system
JP2010133303A (en) Internal combustion engine with supercharger
US10634044B2 (en) Engine system and method using the same

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 06806524

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06806524

Country of ref document: EP

Kind code of ref document: A1