Mercedes has introduced a new line of engines that are capable of running in a “lean-burn” mode that improves fuel efficiency and emissions. However, because of the sulfur content in gasoline here in the US of A, these engines will not be imported into the US.
Ultra Low Sulfur Diesel has been available here in the US after the government limited the amount of sulfur in diesel to 15 parts per million. But the sulfur limits in gasoline are too high for the Mercedes engines, which are rated at 80-95 ppm.
The new four and six bangers from Mercedes can’t operate their lean-burn combustion cycles because their threshold is 50 ppm. And the higher amount of sulfur in the fuel would significantly affect the catalytic system. The lean-burn system first debuts in the new SLK for Europe, in the 3.5L direct-injection V6. The V6 in the new C350 is rated at 302 hp and 273 lb-ft, up from 268 and 258. With the new lean-burn system, economy has been improved by 5% to a combined 21 mpg.
The new direct-injection V6 will be found in the US E-Class, M-Class and SLK very soon, obviously sans the lean-burn system.
A new turbocharged four-banger will also be reintroduced into the mix after a seven-year hiatus and will be featured in the new C-Class.
And lastly, a new 4.6L Bi-turbo direct injection V8 will be available for the new 2011 CL550 coupe, raising the power to 429hp and 516 lb-ft of torque while improving fuel economy to 15/23 mpg, ridding of the CL’s requirement for a gas guzzler tax. The V8 will also find its way into the 2012 S-Class, E-Class and CLS.
– By: Chris Chin
Source: Wards Auto