New Mercedes-Benz engines won’t be available in the U.S. as fuel is too ‘dirty’

Article by Christian Andrei, on March 22, 2011

Mercedes-Benz can boast of having a new engine lineup that’s so advanced that it can operate in a “lean-burn” mode that is very fuel-efficient and also has reduced emissions.

But since sulfur content in gasoline remains too high, it won’t be offered in the U.S. Ultra Low Sulfur Diesel federal regulations limit sulfur content to 15 parts per million and so most of the sulfur has been removed from U.S. diesel fuel.

The U.S. Environmental Protection Agency sets the sulfur limits for gasoline much higher – 80 ppm at the refinery gate and 95 ppm downstream.

Bernhard Heil, vice president-powertrain development for Mercedes-Benz, told Ward’s that new 4- and 6-cyl. engines from Mercedes run on lean-burn combustion cycles but they don’t work properly if sulfur levels in fuel are above 50 ppm.

He said that those are “definitely too much.” Mercedes sells these “Stratified” engines in Europe that run at a much leaner fuel-to-air ratio than conventional engines, getting higher fuel efficiency.

These engines will not be available in the U.S. until its gasoline is cleaned up as the excessive sulfur will overwhelm and “poison” the trap that captures oxides of nitrogen from the exhaust stream. This trap is required since the Stratified combustion cycle inherently produces higher concentrations of NOx.

Since a conventional 3-way catalyst will not work with a lean-burn engine, the NOx must be adsorbed and stored in a specially designed trap before it is burned off. Heil said that integrating a lean-burn combustion cycle boosts fuel efficiency up to 10%. He said that sulfur in gasoline, by itself, does not affect fuel economy.

In May 2010, the Obama administration told the EPA to consider the effect of lower sulfur levels in gasoline, as well as other factors, on greenhouse-gas emissions.

The EPA has yet to complete its review. Heil said that the European Union has already cut sulfur content in gasoline “to near zero.” Actually, this problem isn’t just in the U.S., as the gasoline in Africa and developing countries in Asia is “comparably worse.” [via Ward's Auto]

If you liked the article, share on:

Comments

Login or Create new account to add a comment!

Recommended

Back in 2009, Nissan first introduced the Nissan Leaf, the company’s first all-electric vehicle. LEAF stands for Leading Environmentally-friendly Affordable Family car and this particular EV has been considered as...
by - December 3, 2016
In the minivan segment, the 2017 Chrysler Pacifica is already impressive in terms of fuel economy figures – as rated by the United States Environmental Protection Agency. In fact, the...
by - December 2, 2016
Having a blacked-out Bentley Mulsanne Speed is already menacing by itself but by naming it as the Bamford X, it became all the more imposing. This model was made by...
by - December 2, 2016
We have good news for those who are waiting for the latest version of the Mazda CX-5 compact crossover. It was just unveiled in November at the 2016 Los Angeles...
by - December 2, 2016
Those familiar with racing know that Marco Wittmann’s win during the 2016 Deutsche Tourenwagen Masters held last May was noteworthy as it was his second title in four seasons. In...
by - December 2, 2016
Facebook

Youtube Channel

Tip Us
Do you have a tip for us?
Did you film an important event?
Contact us
Newsletter
Subscribe to our newsletter!
Subscribe
Galleries