Abstract
Keywords - SCR, SINOx ® , NOx Conversion, Catalytic Converter, Emission Control
Abstract - The Selective Catalytic Reduction (SCR) is one of the most efficient technologies to reduce nitrogen oxide (NOx) emissions arising from technical combustion processes. As global emission limits for heavy-duty (HD) Diesel engines become more stringent, emission control systems will be required to meet the government mandated emission limits.
SCR has already proven its capability as an efficient method for achieving high NOx reduction rates in both stationary and transient test cycles of Japanese, European, and US test procedures. In addition to superior NOx reduction rates achieved with SCR systems in various steady-state and transient cycles, the SCR technology can also provide for a significant reduction of particulate matter in Diesel engine emissions. Using the SCR system, a clear decrease of PM even in the range of nano-particulates relevant to health issues can be found. Moreover SCR technology enables a fuel-optimised engine calibration. A possible reduction in fuel consumption using modern Diesel engines of up to 7 % compared to alternative emissions control strategies has been reported. So the SCR technology is also an efficient tool to cut CO2 emissions as demanded in the Kyoto Protocol.
The durability of SCR systems has been proved in several fleet tests with HD trucks equipped with SCR systems worldwide.
This paper reviews possible strategies to comply with future emission regulation in Europe, USA and Japan considering SCR technology as part of them. It will be shown that the SCR technology can offer a significant contribution for achieving Euro 4 and 5, Japanese long-term regulation and even very stringent US 2007-2010 emission limits. For the later combinations of the SCR system with different emission control technologies as particulate filters, EGR and auxiliary catalysts have shown promising results.