Bluetec Emission Control System for the US Tier 2 Bin 5 Legislation 2008-01-1184
While the market share for diesel engines for LD vehicles in Europe has grown continuously in the past years, the market share in North America is still negligible. Until now, it has been possible to fulfill the limits for nitrogen oxides (NOx) both in Europe and in North America by engine measures alone, without using an active NOx aftertreatment system. With the introduction of Tier II Bin 8 and Tier II Bin 5 emissions legislation in the US in 2007, most new diesel applications will now require NOx aftertreatment.
One of the possible technologies for the reduction of nitrogen oxides in lean exhaust gas is the NOx storage catalyst which has become the generally-accepted choice for engines with gasoline direct injection systems and which is also utilized in the current diesel Bluetec I systems from Daimler. For heavier applications urea-SCR is the preferred technology to fulfill NOx legislation limits. For the heavy duty sector urea-SCR technology is already in use in series production and is under development for the introduction of heavy passenger vehicles to meet the Bin 5 legislation in the US.
This publication will show the requirements for the Bluetec emission control system, including DOC, catalyzed DPF, and SCR catalyst in order to fulfill the Bin 5 emissions legislation. It will also discuss some approaches on how to address these requirements. For this purpose the results of several investigations including model gas testing, engine bench testing, and vehicle evaluations will be presented.