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Journal of Power Sources 84 1999 203–213
www.elsevier.comrlocaterjpowsour
Fuel cell power trains for road traffic
Bernd Hohlein
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, Peter Biedermann, Thomas Grube, Reinhard Menzer
¨
()
Forschungszentrum Julich IWV3 , D-52425 Julich, Germany
¨¨
Accepted 28 June 1999
Abstract
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Legal regulations, especially the low emission vehicle LEV laws in California, are the driving forces for more intensive
technological developments with respect to a global automobile market. In the future, high efficient vehicles at very low emission levels
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will include low temperature fuel cell systems e.g., polymer electrolyte fuel cell PEFC as units of hydrogen-, methanol- or
gasoline-based electric power trains. In the case of methanol or gasolinerdiesel, hydrogen has to be produced on-board using heated
steam or partial oxidation reformers as well as catalytic burners and gas cleaning units. Methanol could also be used for direct electricity
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generation inside the fuel cell direct methanol fuel cell DMFC . The development potentials and the results achieved so far for these
concepts differ extremely. Based on the experience gained so far, the goals for the next few years include cost and weight reductions as
well as optimizations in terms of the energy management of power trains with PEFC systems. At the same time, questions of fuel
specification, fuel cycle management, materials balances and environmental assessment will have to be discussed more intensively. On
the basis of process engineering analyses for net electricity generation in PEFC-powered power trains as well as on assumptions for both
electric power trains and vehicle configurations, overall balances have been carried out. They will lead not only to specific energy
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demand data and specific emission levels CO , CO, VOC, NO for the vehicle but will also present data of its full fuel cycle FFC in
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x
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comparison to those of FFCs including internal combustion engines ICE after the year 2005. Depending on the development status
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today or in 2010 and the FFC benchmark results, the advantages of balances results of FFC with PEFC vehicles are small in terms of
specific energy demand and CO emissions, but very high with respect to local emission levels. q 1999 Elsevier Science S.A. All rights
2
reserved.
Keywords: Fuel cell systems; Internal combustion engine; Power trains; Road traffic
1. Introduction
In development work, benchmark and prototype tests as
well as process engineering and systems analyses, efforts
are made worldwide to improve the balances of full fuel
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cycles FFCs for power trains in road traffic. This is done
including secondary energy carriers in the vehicle tank
other than gasoline and diesel. The different solution ap-
proaches all serve to reduce the vehicles’ specific energy
demand and fuel supply as well as to minimize specific
vehicle and fuel cycle emissions. As far as the emissions
are concerned, it is also important to optimize the quality
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i.e., the composition of the hydrocarbon emissions in the
sense of minimizing the secondary pollutants, such as
wx
ozone 1 .
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Corresponding author. Tel.: q49-2461-61-3235; fax: q49-2461-61-
8109
The development of passenger cars for the future is
currently focused on conventional car power trains. How-
ever, among the novel power trains with low specific
energy demand and emissions compared to conventional
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power trains with internal combustion engines ICE , elec-
tric power trains with fuel cell systems undoubtedly repre-
sent a great challenge. The present analysis of such electric
power trains and a comparison with future conventional
power trains with ICEs can provide information about the
options of novel power trains with fuel cell systems for
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passenger cars of the future 2 .
2. New energy carriers and power trains in road traffic
If advanced power trains with ICEs based on conven-
tional fuels will fulfill future energy demand and emission
standards and if sufficient gasoline and diesel will be
0378-7753r99r$ - see front matter q 1999 Elsevier Science S.A. All rights reserved.
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PII: S0378-7753 99 00318-3