The
Volvo SCR system is simple and effective, with few
components. It consists of a DEF tank positioned
near the standard diesel tank, plus a DEF tank pump,
an injector unit and an SCR catalytic converter.
The advantage
of using DEF is that it enables the engine to use
less EGR -- and higher oxygen levels -- for better
combustion, while easily meeting the EPA's near-zero
NOx emissions requirement of 0.2 g/hp-hr NOx. By
using DEF, we avoid the disadvantages of increasing
EGR to massive levels.
This
results in better fuel efficiency from your engine.
With rising crude oil prices, achieving maximum fuel
efficiency has become the single most important
attribute of modern truck engine design.
1.
Diesel engine optimized for high performance,
low particle emissions and low fuel
consumption.
2. DEF tank.
3. The DEF tank and injection system's
control units continuously vary the amount of
DEF injected in response to the engine's
current load conditions.
4. DEF is injected into the exhaust
gases in between the PDF (5) and the Catalytic
Converter (6).
5. Diesel Particulate Filter.
6. In the Catalytic Converter, nitrogen
oxides are transformed into harmless nitrogen
gas and water.
7. The system notifies the driver when
it is time to top up with DEF. |
SCR For 2010
Q: What is SCR?
A:
SCR stands for Selective Catalytic Reduction, an
emissions technology designed to help bring diesel
truck engines into compliance with new EPA
regulations going into effect in 2010. With SCR
technology, diesel exhaust fluid (DEF), a water
solution of urea, is injected into the exhaust
stream to convert nitrogen oxide (NOx) into
harmless nitrogen and water vapor.
Q: Why use SCR?
A:
SCR is a
straightforward NOx aftertreatment system with the
following advantages:
-
Superior fuel economy compared
to other solutions for EPA '10.
-
Total fuel costs will be
significantly reduced, even allowing for the
DEF.
-
Simple solution requiring no
changes to today's engines and cooling packages.
-
In fact, since the amount of
exhaust gas recirculated can be reduced, engine
performance can be
enhanced and cooling requirements reduced.
-
Very little maintenance
required.
-
Reliable, proven approach.+ SCR
is already proven in high volume production.
Q: What makes up the Volvo SCR
system?
A:
Volvo's SCR
system consists of just a DEF tank, an injector,
sensors and wiring harness, and a catalyst.
Q: Does the driver have to do
anything to operate SCR?
A
:
The system operates automatically—all the driver
has to do is monitor an indicator on the dash and
top off
the DEF tank when necessary. Warnings for low DEF
levels similar to those for other fluids, like
diesel, are included.
Q: What is the range for a tank of
DEF?
A:
This depends
upon the job the truck is doing and tank size.
Several DEF tank sizes will be available, and
a range of up to 4,000 miles will be available for
line-haul service. Volvo will work with customers
in all applications to optimize operation.
Q: Exactly what is Diesel Exhaust
Fluid (DEF)?
A:
DEF is a
solution of 67.5 percent water and 32.5 percent
urea. Urea is a non-hazardous nitrogen-based
compound commonly used in fertilizer.
Q: How does the DEF affect truck
weight?
A:
For every
100 gallons of diesel fuel, two to four gallons of
DEF will be required. And a gallon of DEF weighs
an estimated 8.3 pounds.
Q: Where will DEF be available?
A:
Bulk DEF
filling stations are being set up at truck stops
and diesel service stations across North
America.In addition, containers of DEF will be
sold at truck stops, dealerships, parts stores and
other retail locations.
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