An ammonia sensor for diesels
Delphi Corp., Troy, Mich., says it has developed the first automotive ammonia sensor.
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Delphi Corp. claims its
ammonia sensor will reduce
ammonia emissions from
vehicles and lower running
costs for vehicle operators.
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Delphi Corp., Troy, Mich., says it
has developed the first automotive ammonia sensor. It should
improve closed-loop control of
selective catalytic-reduction
(SCR) systems used in an increasing number of diesel vehicles to
reduce NOx. The sensor
measures tailpipe ammonia so
the converter knows how much
urea to inject.
Controlling urea injection
should become increasingly
important, as SCRs must meet
new emissions regulations in
both light and heavy-duty diesel
markets. SCRs inject ammonia, in
the form of liquid urea, into the
exhaust ahead of the NOx reduction catalyst. Ammonia
converts the gas into nitrogen
and water. Unreacted ammonia,
known as "slip," escapes with the
exhaust gases.
"With the growth of vehicles
using SCRs, ammonia emissions
are a potential problem that we
want to address before it
becomes an environmental
issue," says Guy Hachey,
president of Delphi Powertrain.
In the atmosphere, ammonia
reacts with compounds such as
nitric acid to create dust-sized
particles, which can create
smoglike haze. Ammonia
emissions from vehicles,
however, are only a small portion
of total ammonia emissions. The
biggest sources are livestock and
factories.
SCRs will also be used on
passenger cars in the U.S. to help
comply with Tier II Bin 5 regulations for light-duty vehicles.
Delphi is working with vehicle
manufacturers in Asia, North
America, and Europe on the new
ammonia sensor, which is
expected to reach production in
2010.
MAKE CONTACT
Delphi Corp.,
delphi.com