|The 320 BLUETEC|
Mercedes-Benz unveiled the previously-announced E 320 BLUETEC—its “50-state ready” clean diesel car (earlier post)—at the New York International Auto Show.
The E320 BLUETEC, one of the new-generation of E-Class vehicles being rolled out by Mercedes (earlier post), uses a new 3.0-liter V6 turbodiesel engine producing 221 horsepower (165 kW) and 510 Nm of torque, which replaces the in-line six found in the previous E320 CDI.
The engine design includes includes four valves per cylinder, centrally located piezo-electric injectors, third-generation CDI direct injection, a turbocharger with variable nozzle turbine and exhaust gas recirculation.
Combined with a seven-speed automatic transmission, the E320 BLUETEC accelerates from 0 to 60 mpg in 6.6 seconds and now has a preliminary estimated fuel economy rating of 31 mpg US combined (27 city, 37 highway).
The E320 BLUETEC incorporates three after-treatment units in the exhaust stream: an oxidizing catalytic converter, a particulate filter and a denox storage converter that absorbs nitrogen oxides temporarily.
The BLUETEC system depends on the use of ultra low-sulfur diesel fuel (less than 15 parts per million) that becomes mandated in the US this fall. The availability of extremely low-sulfur fuel enables the use of reliable particulate filters and efficient nitrogen oxide aftertreatment.
For more aggressive emissions aftertreatment, a BLUETEC system can move up an AdBlue injection system. A water-based urea solution, AdBlue is carried in its own small tank and metered into the exhaust in minute quantities, so small that the tank only needs to be refilled during routine scheduled maintenance.
When AdBlue is injected into pre-cleaned exhaust gas, ammonia (NH3) is released, converting nitrogen oxides into harmless nitrogen (and water) in a downstream catalytic converter. This is the version of BLUETEC technology Mercedes will apply in the larger GL BLUETEC full-size SUV, and Chrylser in its concept Jeep BLUETEC. (Earlier post.)
Mercedes also announced at the show that it is launching two more diesel-powered models into the US for 2007: the R320 CDI sports tourer and the ML320 CDI sport utility, both using the V6 diesel. These are not BLUETEC-equipped. However, with their precise full electronic control of fuel delivery along with an oxidation catalyst for aftertreatment, the current Mercedes-Benz diesel 3.0-liter engine can pass 45-state emissions standards.