cdti_deer_2008_srg-scr_presentation - Selective Catalytic Reduction and Exhaust Gas Recirculation Systems Optimization Clean Diesel Technologies Inc

cdti_deer_2008_srg-scr_presentation - Selective Catalytic...

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© Clean Diesel Technologies, Inc 1 Selective Catalytic Reduction and Exhaust Gas Recirculation Systems Optimization
© Clean Diesel Technologies, Inc 2 Abstract The first generation of on-board vehicle urea-selective catalytic reduction systems generally employed compressed air to achieve efficient injection and the atomization of urea into the exhaust stream and for uniform ammonia delivery fro reduction of nitrogen oxides across the SCR catalyst. The field experience with these SCR systems has shaped the requirements for the next generation of systems. These requirements include substantially reduced system cost and complexity, enhanced durability and accuracy of urea delivery, to control injection across the full duty cycle and operating temperatures, and to maintain system cleanliness, avoiding potential for injector and system deposits. This experience has resulted in the demand for a new generation of airless injection systems, such as the airless ARIS ® technology, which incorporates single fluid return flow liquid cooled injection for reliability, simplicity and low cost. The ARIS airless injection system and control technologies have imbedded a series of performance refinements. The ARIS approach provides robust and flexible designs for SCR systems in OEM or retrofit applications. In order to enable manufacturers and Tier One suppliers to optimize NOx and PM control while minimizing fuel consumption, the strategy for the combination of EGR with SCR was invented. This patented EGR - SCR approach from Clean Diesel Technologies was shown to readily meet the 2010 requirements for NOx and PM emissions, through independent test programs. This strategy enables the engine manufacturer to optimize in- cylinder combustion conditions with EGR, and to integrate with SCR at reduced EGR rate to achieve low NO x emissions with fuel efficiency over the entire engine operating range. This combination can be optimal using an efficient SCR injection and control strategy such as ARIS. The operating principles and examples of applications experience with these systems will be provided.
© Clean Diesel Technologies, Inc 3 Urea / Ammonia injection: Enabling SCR technology Initial SCR systems designed for EURO IV Heavy duty employed air assisted Urea injection systems to ensure adequate injector cooling and urea dispersion in the exhaust Next Generation Airless Urea Injection systems have become available, offering simplified and more cost effective solutions for Urea injection Urea (Diesel Emissions Fluid - DEF or AdBlue aqueous solution) has become the preferred reagent for SCR applications in Europe and the U.S.

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