The document discusses new innovations in selective catalytic reduction (SCR) systems, including an ammonia sensor developed by Delphi that allows for more efficient emissions control by optimizing NOx conversion rates. The sensor measures ammonia levels in the exhaust from 0-100ppm and provides feedback to control urea dosage. This closed-loop system enables direct optimization of urea levels based on emissions measurements. Manufacturers will need further innovative designs to meet stringent emissions standards for 2020 under potential Euro 7/VII regulations.

1. SCR System and Performance Innovation (Part 2)
The stringent standards that are set out in Euro 6/VI legislation for NOX emissions reduction will be
followed by even stricter targets for 2020 when details of the EU’s Euro 7/VII regulations are
announced. Manufacturers of vehicles, engines, and SCR systems are researching and developing
systems and components which can improve performance and efficiency, to enable them to meet
these standards.
New innovations in components are being designed continually as the industry gathers pace, and two
of the most recent advances are detailed below.
Delphi SCR ammonia (NH3) sensor technology
Due for initial production in 2012, Delphi has developed an ammonia sensor for the automotive
industry, which enables more efficient emissions control. The system allows the SCR to work at
optimized NOX conversion rates, which in turn improves fuel efficiency.
The sensor dynamically measures the content of ammonia in emissions and the system can adapt the
urea dosage accordingly. Some existing SCR technology use a timed urea dosing process; without
accurate means of measurement and control excess and residual ammonia can escape via the exhaust
stream. It is anticipated that part of the EU directives will relate to the control of ammonia slip from
SCR systems, so the monitoring of ammonia levels will soon be an essential requirement.
Source: Delphi
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2. The ammonia sensor is placed downstream of the SCR catalyst and NOX sensor; it detects the levels of
ammonia in the exhaust stream over a range of 0-100ppm. The sensor converts the ammonia into an
electrical signal that the electronic control system uses to control the urea solution dosage.
The ammonia sensor is the first technology that enables an SCR system to have a direct closed loop
control system; allowing the optimisation of the urea dosage to be controlled by measurement of the
emissions.
Future innovation and design
SCR systems have been developed and improved upon very quickly since the EU implemented their
emissions strategy and the standards for the industry to comply with. To develop SCR systems to meet
requirements of Euro 6/VI regulations, and systems that can be used beyond 2020, manufacturers will
require more innovative designs to provide even greater efficiency.
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and developments in SCR systems?
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IQPC GmbH | Friedrichstr. 94 | D-10117 Berlin, Germany
t: +49 (0) 30 2091 3330 | f: +49 (0) 30 2091 3263 | e: eq@iqpc.de | w: www.iqpc.de
Visit IQPC for a portfolio of topic-related events, congresses, seminars and conferences: www.iqpc.de