Delphi's Ground-Breaking SCR Dosing System Reduces Both NOx and CO2
2010年7月22日 - 2:47AM
Marketwired
Delphi Automotive has developed a breakthrough in NOx control for
diesel engines with a new selective catalytic reduction (SCR)
system that improves the performance, packaging and long-term
reliability of the system as well as reduces vehicle CO2 emissions
by up to 1g/km over any comparable system.
By injecting aqueous urea solution into a SCR system at up to
four times the pressure of any previous system, which allows the
catalyst to be close coupled to the engine, Delphi has solved many
of the issues associated with other SCR systems.
"As the EU regulations for CO2 emissions take effect, every
additional gram of CO2 could potentially cost the manufacturer up
to 95 euros per vehicle in future emissions-related penalties,"
said Peter Spadafora, Delphi product team leader, SCR Systems. "The
Delphi SCR system reduces both NOx and CO2 emissions in order to
add maximum value for our customers."
A modular architecture The system consists
of three basic modules. The SCR doser (an injector with integrated
high pressure pump) is mounted in the exhaust line just ahead of
the SCR catalyst and injects the urea solution at 20 bar directly
into the exhaust stream. The solution is supplied to the injector
by a low pressure pump within the Urea Delivery Module (UDM) in the
remote urea tank. The third element of the system is the
electronics and software used to control the dosing subsystem.
The high pressure of the dosing injector, combined with an
innovative insulation arrangement, prevents the urea solution from
boiling within the doser, allowing its tip to be directly exposed
to the hot exhaust. This unique architecture puts more energy into
the urea spray which requires less mixing energy from the exhaust
and eliminates deposit formation at the nozzle tip. It also ensures
consistent spray performance over the entire life of the system.
The superior performance of the Delphi doser allows exhaust
designers to move the SCR catalyst closer to the engine which in
turn saves on CO2 as catalyst heating and light-off strategies can
be reduced.
Unlike alternative systems that use timed injector opening, the
Delphi system uses a positive displacement solenoid pump that
delivers an accurate, metered quantity of urea through the
injector, regardless of supply pressure, throughout the lifetime of
the system.
"As an experienced diesel fuel injection supplier, Delphi has
the ideal combination of design and high-volume precision
manufacturing expertise necessary to develop this new system,"
explained Spadafora. "In total, we now have 52 SCR patents and
another 20 applications pending."
Additionally, the Urea Delivery Module (UDM) can be customized
to integrate the functions of urea level sensing, lifetime
filtration, heating for defrosting in winter and a delivery pump,
packaging conveniently into the base of the tank. The delivery pump
is only required to pressurise the urea solution to prevent boiling
in the feed lines.
Simplified installation into the vehicle
The modular architecture of the main system elements simplifies
installation into the vehicle and offers flexibility to individual
vehicle manufacturers. Depending upon customer preference, Delphi
can provide either a Dosing Control Unit, a simple Heater Control
Module or just the software and electrical interface specifications
to control the dosing sub-system. Where required, Delphi can also
provide system services to specify and calibrate the dosing
sub-system. Currently applicable to passenger cars and light
commercial vehicles, the technology is also being developed with
higher flows to suit medium- and heavy-duty diesels.
"Diesels provide an outstanding solution to the problem of CO2
reduction but, until now, the requirement to reduce NOx and CO2
simultaneously has been a challenge," concluded Spadafora.
"Delphi's high pressure SCR dosing system will help vehicle
manufacturers meet stricter NOx requirements such as EU6, Tier 2
bin 5 and corresponding Japanese regulations while improving CO2
emissions and minimising overall system cost."
The first production application of the Delphi SCR system is
scheduled for introduction in 2012.
About Delphi
Delphi is a leading global supplier of electronics and
technologies for automotive, commercial vehicle and other market
segments. Operating major technical centers, manufacturing sites
and customer support facilities in 30 countries, Delphi delivers
real-world innovations that make products smarter and safer as well
as more powerful and efficient. Connect to innovation at
www.delphi.com.
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