At a presentation of the E320 BLUETEC sedan in Las Vegas, Dr Thomas Weber, head of Development at DaimlerChrysler AG and at the Mercedes Car Group said that the company was targeting three US BLUETEC models in the R-Class, ML-Class and the GL Class as early as 2008 that meet the 50-state Bin 5 emissions standard.
The E320 BLUETEC, which will be introduced to the market on 15 October—timed to coincide with the introduction of low-sulfur diesel fuel in the USA—is not Bin-5 compliant, and goes on sale as a 45-state vehicle. (Earlier post.)
|The progression of various emissions standards. Click to enlarge. The EPA Tier 2 Bin 5 / CA LEV II standards are currently the world’s toughest.|
BLUETEC will also be made available in a passenger car model in Europe beginning in 2008. DaimlerChrysler does not plan to restrict the use of BLUETEC to the Mercedes-Benz brand alone, and has shown a Jeep Grand Cherokee BLUETEC concept car.
BLUETEC is DaimlerChrysler’s modular emissions aftertreatment architecture that provides the potential for 50-state compliance—i.e, meeting EPA Tier 2 Bin 5 emissions levels, which map to California LEV II levels.
Mercedes-Benz has developed BLUETEC in two versions: in the E-Class an oxidation-type catalytic converter and particulate filter are combined with an improved, extremely durable NOx trap system and an additional Selective Catalytic Reduction (SCR) catalytic converter.
The second BLUETEC version is based on a urea-SCR system, and this is the one that will deliver Bin 5 compliance.
Here, AdBlue, a non-toxic aqueous carbamide solution is stored in an extra tank and injected into the exhaust-gas stream. Injecting AdBlue into the exhaust gas releases ammonia (NH3), which causes the reduction of up to 80% of the oxides of nitrogen into nitrogen and water in the downstream SCR catalytic converter. Achieving the high efficiency here requires adding precisely the amount of AdBlue needed for the respective particular engine operating state.
Because only around 0.1 liters of AdBlue is needed on average for every 100 kilometers driven (the equivalent of one to three percent of diesel consumption), its tank can be designed in such a way that it only needs to be refilled during regular maintenance checks.
|The NOx trap-based BLUETEC system for the E-Class.||The AdBlue urea-SCR-based BLUETEC system for the GL-class.|
|Click each diagram to enlarge.|
DaimlerChrysler said that it is currently developing the AdBlue urea-SCR system for series production and will apply it primarily in large vehicles and SUVs. The GL- and ML-class vehicles are SUVs; the R-Class is a tourer (wagon).