How SCR Works We changed the emissions, not the engine.
Selective Catalytic Reduction (SCR) technology uses proven, existing engine
architecture, a diesel oxidation catalyst and diesel particulate filter,
plus SCR hardware, to meet EPA 2010 emissions standards. This allows the
engine to function at optimal combustion temperatures, which increases fuel
efficiency and reliability.
SCR reduces tailpipe nitrogen oxide emissions (NOx) by treating the exhaust
stream with a spray of diesel exhaust fluid (DEF). DEF, along with the
exhaust heat and a catalyst, converts NOx into nitrogen and water vapor,
which are clean, harmless and present in the air we breathe every day.
It is our mission to provide reliable, durable, safe and innovative buses to
our customers. And SCR technology, with its near-zero emissions, is the
environmental choice to do just that.
Simple, Cost-effective, Ready
It's Simple
Because of the many benefits SCR technology offers purchasers, drivers and
technicians, SCR is the clear choice for meeting EPA 2010 emission
standards.
· Engine changes are minimized and efficiency is maximized because
SCR is an aftertreatment technology.
· Maintains all the options you expect, from A/C condensers and
roomy luggage compartments to wheelchair lifts
· Maintains daily ease of use. Requires only a glance at the
dash-mounted diesel exhaust fluid (DEF) gauge.
· Eliminates driver fill ups. DEF tank fill intervals allow for fill
at regular technician servicing.
It's Cost-effective
With a reliable and proven engine architecture, SCR is the only clean-air
technology that actually pays you back over the life of your bus.
Cummins Inc. conducted testing of both SCR and In-cylinder EGR systems and
determined that SCR technology is better for customers because of the
following:
· In-cylinder EGR reduces engine life by 20-25%
· SCR has greater component reliability
· SCR technology achieves a 5-9% fuel economy advantage over
In-cylinder EGR
A 9% increase in fuel efficiency saves $270 per bus per year.
It's Ready
Thomas Built's SCR emission technology is ready.
SCR is the mainstream technology that manufacturers of 90 percent of North
American on-highway engines will use to meet 2010 emission standards:
Daimler Trucks
<http://www.daimler.com/dccom/0-5-540400-1-540413-1-0-0-0-0-0-8-7145-0-0-0-0
-0-0-0.html> , Cummins
<http://www.cummins.com/cmi/index.jsp?siteId=1&langId=1033&newsInfo=true>
and Detroit Diesel <http://www.detroitdiesel.com/emissions> . And in the
consumer car industry, BlueTec is becoming the SCR technology of choice.
Currently, SCR systems can be found in Mercedes-Benz, Audi, BMW, Jeep, Kia,
Mini, Volkswagen and Hyundai.
The technology backed by millions of miles. Daimler Trucks alone logged more
than 30 million SCR testing miles in North America and 2,500,000 customer
test miles. More than 600,000 SCR vehicles operate in Europe, from
Scandinavia to the Mediterranean, and more than 245,000 of them are Daimler
and/or Cummins SCR vehicles.
Compare Technologies Why SCR? See for yourself.
When looking at both systems, Thomas Built decided that SCR was the more
reliable and fuel-efficient option. The charts below outline the differences
of In-cylinder Exhaust Gas Recirculation (EGR) and SCR technology.
<http://www.thomasbus.com/resources/resources_green.asp> Green Technology
Resources
<http://www.thomasbus.com/_pdf/brochure-scr.pdf> Download Our SCR Brochure
SCR
Advantages of SCR
· Lowers need for EGR
· Permits engine to operate under optimized combustion conditions,
including increased temperature, increased pressure and excess oxygen
· Less heat rejection
· Cleaner available tailpipe emissions
· Proven technology across the globe
· Mainstream choice for 2010 solution
Customer Benefits
· Better fuel efficiency
· Less component stress
· Fewer regenerations relative to In-cylinder EGR
· Improved durability
· Expected lower total cost, which includes maintenance and fuel
· End emission products are nitrogen, water and carbon dioxide
· Decreased CO2 emissions
In-cylinder EGR
Disadvantages of In-cylinder EGR
· Less efficient combustion process requires lower temperatures
· Increased heat rejection causes the engine to produce more heat
· Higher injection pressures
· Decreased power density with same displacement size
· Increased diesel particulate matter (soot)
· Increased air flow and cooling capacity
Customer Impact
· Decreased fuel efficiency
· Increase in regenerations and fuel burned
· Increased complexity in turbo chargers, vehicle coolers, pistons
and injectors
· Decreased engine durability
· Oil degradation
DEF BenefitsWidely available. Clearly safe.
Because SCR uses diesel exhaust fluid (DEF), we are able to avoid the
disadvantages associated with increasing EGR to the extreme levels necessary
to meet the EPA requirement of near-zero NOx emissions (0.2g/bhp-hr).
DEF is an aqueous solution of 32.5% urea and 67.5% de-ionized water. It is
clear, non-toxic, biodegradable and non-flammable. What's the big advantage
of DEF? Maximized fuel efficiency. The higher oxygen levels DEF provides
offer more efficient combustion resulting in clean nitrogen and water
emissions.
Find DEF locations <http://finddef.com/def_map.php> .
Fast facts about DEF
· Non-toxic, biodegradable and non-flammable
· A 32.5% urea solution
· DEF freezes at 12° Fahrenheit
· DEF is not damaged when frozen and is usable when thawed
· Vehicle is fully operational when DEF is frozen
· Weight: 9.21 lbs. per gallon
· Shelf life: approximately 6-18 months depending on storage
temperature
· DEF is expected to cost the same as diesel fuel
· You will use approximately 1.5 gallons of DEF for every 100
gallons of diesel fuel
· Container sizes include 2.5-gallon, 55-gallon tote, 275-gallon
tote and bulk
· Bus will not shut down if DEF tank is empty
· Available from your local Thomas or Cummins dealer, truck stops
and the same distribution channel where you buy other shop fluids
· FAQ Get the answers about SCR.
· To help you better understand how SCR works, we've included a list
of frequently asked questions. For more information, visit this educational
site, www.factsaboutscr.com.
· Question: Why SCR with DEF?
· Answer: The advantage of using DEF is that it enables the engine
to use less EGR and higher oxygen levels, offering more efficient
combustion. DEF allows us to avoid the disadvantages of increasing EGR to
extreme levels and meets the EPA's requirements of near-zero NOx emissions
(0.2g/bhp-hr). The results are maximum fuel efficiency and an emission of
nitrogen and water, which are elements in the air we breathe every day.
Posted:11-24-2008
· Question: What is DEF?
· Answer: DEF stands for diesel exhaust fluid, which is an aqueous
solution of 32.5% urea and 67.5% deionized water. It is clear, non-toxic,
biodegradable and non-flammable. Posted:11-24-2008
· Question: How do I know when my vehicle is low on DEF?
· Answer: A dash-mounted gauge will notify drivers via an escalating
driver-warning system as DEF tank levels reduce. Ample warning will be given
before the DEF tank empties. An empty tank will not cause the bus to shut
down while driving. A five mph de-rate will only occur after the bus has
been turned off and restarted. Full power will resume after DEF tank is
filled. Updated:05-27-2009
· Question: Will the 2010 Emissions Cummins engines be compatible
with BioDiesel?
· Answer: Cummins products are compatible with up to B20. 2010
products will also maintain the ability to use up to B20. Posted:06-10-2009
· Question: Is there a fuel economy difference from the 2007
Emissions Cummins engine and the new 2010 Emissions Cummins engine?
· Answer: 2007 and 2010 midrange Cummins products will be comparable
in fuel economy, however if Cummins would have gone to 'in-cylinder' we
would have lost 5-9% in fuel economy. Posted:06-10-2009
· Question: Will the amount of Nitrogen exhaust be enough to ignite
to flame?
· Answer: No. Nitrogen is not flammable. Posted:06-10-2009
· Question: What is the life of the SCR system and its components?
· Answer: The SCR system is designed to last the life of the engine.
Posted:06-10-2009
· Question: What are the preventive maintenance requirements on the
SCR system on the 2010 Emissions Cummins engine?
· Answer: There are no preventive maintenance requirements other
than a DEF filter that will need to be serviced at 200,000 miles.
Posted:06-10-2009
· Question: How many sensors are there on the 2010 Emissions SCR
System for the Cummins Engine and a Thomas Built Bus?
· Answer: 2 NOx sensors, 2 temperature sensors and a diesel exhaust
fluid level sensor. Posted:06-10-2009
· Question: Will diesel exhaust fluid degrade at higher temperatures
(above 85° F) if it is stored in a sealed container?
· Answer: In order for diesel exhaust fluid to degrade while stored
at higher temperatures it must be stored at over 85°F for over 6 months. If
the temperature decreases during that time of storage, then the storing
timeline is increased. DEF stored at below 85°F will provide for a 12 to 18
month shelf life. Posted:06-10-2009
· Question: Does diesel exhaust fluid freeze and at what
temperature?
· Answer: Diesel exhaust fluid freezes at 11°F/-11°C. It does not
freeze as a solid block at that temperature, but it has a 'slushy'
consistency. To freeze to a solid mass requires temperatures below
-20°F/-25°C for 48 hours. From a solid frozen mass, the system will take
approximately 40 minutes to thaw the diesel exhaust fluid, which is faster
than required by the EPA. Posted:06-10-2009
· Question: Are there any biohazard requirements of concerns for
diesel exhaust fluid? Any clean up requirements?
· Answer: No. Diesel exhaust fluid does not have a bio-hazard clean
up requirement. Posted:06-10-2009
Take a look at the diagram below to see how SCR works.
img-what-is-scr.gif
Buds Sig.
Sent from my iPad
Selective Catalytic Reduction (SCR) technology uses proven, existing engine
architecture, a diesel oxidation catalyst and diesel particulate filter,
plus SCR hardware, to meet EPA 2010 emissions standards. This allows the
engine to function at optimal combustion temperatures, which increases fuel
efficiency and reliability.
SCR reduces tailpipe nitrogen oxide emissions (NOx) by treating the exhaust
stream with a spray of diesel exhaust fluid (DEF). DEF, along with the
exhaust heat and a catalyst, converts NOx into nitrogen and water vapor,
which are clean, harmless and present in the air we breathe every day.
It is our mission to provide reliable, durable, safe and innovative buses to
our customers. And SCR technology, with its near-zero emissions, is the
environmental choice to do just that.
Simple, Cost-effective, Ready
It's Simple
Because of the many benefits SCR technology offers purchasers, drivers and
technicians, SCR is the clear choice for meeting EPA 2010 emission
standards.
· Engine changes are minimized and efficiency is maximized because
SCR is an aftertreatment technology.
· Maintains all the options you expect, from A/C condensers and
roomy luggage compartments to wheelchair lifts
· Maintains daily ease of use. Requires only a glance at the
dash-mounted diesel exhaust fluid (DEF) gauge.
· Eliminates driver fill ups. DEF tank fill intervals allow for fill
at regular technician servicing.
It's Cost-effective
With a reliable and proven engine architecture, SCR is the only clean-air
technology that actually pays you back over the life of your bus.
Cummins Inc. conducted testing of both SCR and In-cylinder EGR systems and
determined that SCR technology is better for customers because of the
following:
· In-cylinder EGR reduces engine life by 20-25%
· SCR has greater component reliability
· SCR technology achieves a 5-9% fuel economy advantage over
In-cylinder EGR
A 9% increase in fuel efficiency saves $270 per bus per year.
It's Ready
Thomas Built's SCR emission technology is ready.
SCR is the mainstream technology that manufacturers of 90 percent of North
American on-highway engines will use to meet 2010 emission standards:
Daimler Trucks
<http://www.daimler.com/dccom/0-5-540400-1-540413-1-0-0-0-0-0-8-7145-0-0-0-0
-0-0-0.html> , Cummins
<http://www.cummins.com/cmi/index.jsp?siteId=1&langId=1033&newsInfo=true>
and Detroit Diesel <http://www.detroitdiesel.com/emissions> . And in the
consumer car industry, BlueTec is becoming the SCR technology of choice.
Currently, SCR systems can be found in Mercedes-Benz, Audi, BMW, Jeep, Kia,
Mini, Volkswagen and Hyundai.
The technology backed by millions of miles. Daimler Trucks alone logged more
than 30 million SCR testing miles in North America and 2,500,000 customer
test miles. More than 600,000 SCR vehicles operate in Europe, from
Scandinavia to the Mediterranean, and more than 245,000 of them are Daimler
and/or Cummins SCR vehicles.
Compare Technologies Why SCR? See for yourself.
When looking at both systems, Thomas Built decided that SCR was the more
reliable and fuel-efficient option. The charts below outline the differences
of In-cylinder Exhaust Gas Recirculation (EGR) and SCR technology.
<http://www.thomasbus.com/resources/resources_green.asp> Green Technology
Resources
<http://www.thomasbus.com/_pdf/brochure-scr.pdf> Download Our SCR Brochure
SCR
Advantages of SCR
· Lowers need for EGR
· Permits engine to operate under optimized combustion conditions,
including increased temperature, increased pressure and excess oxygen
· Less heat rejection
· Cleaner available tailpipe emissions
· Proven technology across the globe
· Mainstream choice for 2010 solution
Customer Benefits
· Better fuel efficiency
· Less component stress
· Fewer regenerations relative to In-cylinder EGR
· Improved durability
· Expected lower total cost, which includes maintenance and fuel
· End emission products are nitrogen, water and carbon dioxide
· Decreased CO2 emissions
In-cylinder EGR
Disadvantages of In-cylinder EGR
· Less efficient combustion process requires lower temperatures
· Increased heat rejection causes the engine to produce more heat
· Higher injection pressures
· Decreased power density with same displacement size
· Increased diesel particulate matter (soot)
· Increased air flow and cooling capacity
Customer Impact
· Decreased fuel efficiency
· Increase in regenerations and fuel burned
· Increased complexity in turbo chargers, vehicle coolers, pistons
and injectors
· Decreased engine durability
· Oil degradation
DEF BenefitsWidely available. Clearly safe.
Because SCR uses diesel exhaust fluid (DEF), we are able to avoid the
disadvantages associated with increasing EGR to the extreme levels necessary
to meet the EPA requirement of near-zero NOx emissions (0.2g/bhp-hr).
DEF is an aqueous solution of 32.5% urea and 67.5% de-ionized water. It is
clear, non-toxic, biodegradable and non-flammable. What's the big advantage
of DEF? Maximized fuel efficiency. The higher oxygen levels DEF provides
offer more efficient combustion resulting in clean nitrogen and water
emissions.
Find DEF locations <http://finddef.com/def_map.php> .
Fast facts about DEF
· Non-toxic, biodegradable and non-flammable
· A 32.5% urea solution
· DEF freezes at 12° Fahrenheit
· DEF is not damaged when frozen and is usable when thawed
· Vehicle is fully operational when DEF is frozen
· Weight: 9.21 lbs. per gallon
· Shelf life: approximately 6-18 months depending on storage
temperature
· DEF is expected to cost the same as diesel fuel
· You will use approximately 1.5 gallons of DEF for every 100
gallons of diesel fuel
· Container sizes include 2.5-gallon, 55-gallon tote, 275-gallon
tote and bulk
· Bus will not shut down if DEF tank is empty
· Available from your local Thomas or Cummins dealer, truck stops
and the same distribution channel where you buy other shop fluids
· FAQ Get the answers about SCR.
· To help you better understand how SCR works, we've included a list
of frequently asked questions. For more information, visit this educational
site, www.factsaboutscr.com.
· Question: Why SCR with DEF?
· Answer: The advantage of using DEF is that it enables the engine
to use less EGR and higher oxygen levels, offering more efficient
combustion. DEF allows us to avoid the disadvantages of increasing EGR to
extreme levels and meets the EPA's requirements of near-zero NOx emissions
(0.2g/bhp-hr). The results are maximum fuel efficiency and an emission of
nitrogen and water, which are elements in the air we breathe every day.
Posted:11-24-2008
· Question: What is DEF?
· Answer: DEF stands for diesel exhaust fluid, which is an aqueous
solution of 32.5% urea and 67.5% deionized water. It is clear, non-toxic,
biodegradable and non-flammable. Posted:11-24-2008
· Question: How do I know when my vehicle is low on DEF?
· Answer: A dash-mounted gauge will notify drivers via an escalating
driver-warning system as DEF tank levels reduce. Ample warning will be given
before the DEF tank empties. An empty tank will not cause the bus to shut
down while driving. A five mph de-rate will only occur after the bus has
been turned off and restarted. Full power will resume after DEF tank is
filled. Updated:05-27-2009
· Question: Will the 2010 Emissions Cummins engines be compatible
with BioDiesel?
· Answer: Cummins products are compatible with up to B20. 2010
products will also maintain the ability to use up to B20. Posted:06-10-2009
· Question: Is there a fuel economy difference from the 2007
Emissions Cummins engine and the new 2010 Emissions Cummins engine?
· Answer: 2007 and 2010 midrange Cummins products will be comparable
in fuel economy, however if Cummins would have gone to 'in-cylinder' we
would have lost 5-9% in fuel economy. Posted:06-10-2009
· Question: Will the amount of Nitrogen exhaust be enough to ignite
to flame?
· Answer: No. Nitrogen is not flammable. Posted:06-10-2009
· Question: What is the life of the SCR system and its components?
· Answer: The SCR system is designed to last the life of the engine.
Posted:06-10-2009
· Question: What are the preventive maintenance requirements on the
SCR system on the 2010 Emissions Cummins engine?
· Answer: There are no preventive maintenance requirements other
than a DEF filter that will need to be serviced at 200,000 miles.
Posted:06-10-2009
· Question: How many sensors are there on the 2010 Emissions SCR
System for the Cummins Engine and a Thomas Built Bus?
· Answer: 2 NOx sensors, 2 temperature sensors and a diesel exhaust
fluid level sensor. Posted:06-10-2009
· Question: Will diesel exhaust fluid degrade at higher temperatures
(above 85° F) if it is stored in a sealed container?
· Answer: In order for diesel exhaust fluid to degrade while stored
at higher temperatures it must be stored at over 85°F for over 6 months. If
the temperature decreases during that time of storage, then the storing
timeline is increased. DEF stored at below 85°F will provide for a 12 to 18
month shelf life. Posted:06-10-2009
· Question: Does diesel exhaust fluid freeze and at what
temperature?
· Answer: Diesel exhaust fluid freezes at 11°F/-11°C. It does not
freeze as a solid block at that temperature, but it has a 'slushy'
consistency. To freeze to a solid mass requires temperatures below
-20°F/-25°C for 48 hours. From a solid frozen mass, the system will take
approximately 40 minutes to thaw the diesel exhaust fluid, which is faster
than required by the EPA. Posted:06-10-2009
· Question: Are there any biohazard requirements of concerns for
diesel exhaust fluid? Any clean up requirements?
· Answer: No. Diesel exhaust fluid does not have a bio-hazard clean
up requirement. Posted:06-10-2009
Take a look at the diagram below to see how SCR works.
img-what-is-scr.gif
Buds Sig.
Sent from my iPad
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