Dear Chaser
A fuel cell is an electrochemical device similar to a battery, but
differing from the latter in that it is designed for continuous
replenishment of the reactants consumed; i.e. it produces electricity
from an external fuel supply of hydrogen and oxygen as opposed to the
limited internal energy storage capacity of a battery. Additionally,
the electrodes within a battery react and change as a battery is
charged or discharged, whereas a fuel cell's electrodes are catalytic
and relatively stable.
Typical reactants used in a fuel cell are hydrogen on the anode side
and oxygen on the cathode side (a hydrogen cell). Typically in fuel
cells, reactants flow in and reaction products flow out, and
continuous long-term operation is feasible virtually as long as these
flows are maintained.
Fuel cells are often considered to be very attractive in modern
applications for their high efficiency and ideally emission-free use,
in contrast to currently more common fuels such as methane or natural
gas that generate carbon dioxide. The only by-product of a fuel cell
operating on pure hydrogen is water vapor. There is concern, however,
about the energy-consuming process of manufacturing the hydrogen.
Manufacturing hydrogen requires a hydrogen carrier (typically fossil
fuels, though water is an alternative), as well as electricity, which
is widely generated by conventional fuels (fossil fuel or nuclear
power). While alternative energy sources like wind and solar power
could also be used, they are presently prohibitively expensive. In
this regard, hydrogen fuel technology itself cannot be said to reduce
fossil fuel dependence.
For more information visit http://en.wikipedia.org/wiki/Fuel_cell
A diagram of a fuel cell at http://www.fueleconomy.gov/feg/fcv_PEM.shtml
Hybrid
Any vehicle is a hybrid when it combines two or more sources of power.
In fact, many people have probably owned a hybrid vehicle at some
point. For example, a mo-ped (a motorized pedal bike) is a type of
hybrid because it combines the power of a gasoline engine with the
pedal power of its rider.
Hybrid vehicles are all around us. Most of the locomotives we see
pulling trains are diesel-electric hybrids. Cities like Seattle have
diesel-electric buses -- these can draw electric power from overhead
wires or run on diesel when they are away from the wires. Giant mining
trucks are often diesel-electric hybrids. Submarines are also hybrid
vehicles -- some are nuclear-electric and some are diesel-electric.
Any vehicle that combines two or more sources of power that can
directly or indirectly provide propulsion power is a hybrid.
The website below has an interactive diagram of both a gasoline car and a hybrid
For more information visit http://auto.howstuffworks.com/hybrid-car1.htm |
