14-09-2013, 04:18 PM
How do Fuel Cells Compare to Internal Combustion Engines and Batteries?
INTRODUCTION
What internal combustion
engines, batteries, and fuel
cells have in common is their
purpose: all are devices that convert
energy from one form to another.
As a starting point, let’s consider the
internal combustion engine — used
to power virtually all of the cars
driven on U.S. highways today.
These engines run on noisy, high
temperature explosions resulting
from the release of chemical energy
by burning fuel with oxygen from
the air. Internal combustion en-
gines, as well as conventional utility
power plants, change chemical
energy of fuel to thermal energy to
generate mechanical and, in the case
of a power plant, electrical energy.
Fuel cells and batteries are electro-
chemical devices, and by their very
nature have a more efficient conver-
sion process: chemical energy is
converted directly to electrical
energy.
If cars were powered by electricity
generated from direct hydrogen fuel
cells, there would be no combustion
involved. In an automotive fuel cell,
hydrogen and oxygen undergo a
relatively cool, electrochemical
reaction that directly produces
electrical energy. This electricity
would be used by motors, including
one or more connected to axles used
to power the wheels of the vehicle.
The direct hydrogen fuel cell vehicle
will have no emissions even during
idling — this is especially important
during city rush hours.