Volkswagen, which over the years has sold 800,000 diesel-powered cars in the U.S., is leaving behind the sooty, smelly diesels of yore by unveiling a new engine that meets the stringent Tier II Bin 5 emissions levels mandated by California and the other states that follow the Golden State’s rules.
History lesson here. Until the advent of ultra-low-sulfur diesel fuel in the fall of 2006, it was not possible to install the latest generation of emissions controls in diesel cars sold in North America—and this meant that many diesel cars could only be sold in states that did not adopt the California rules.
VW's 2 litre common-rail diesel (known by the acronym TDI), which will be available in select models in North America by 2008, promises impressive reductions in nitrous oxide (NOx), a pollutant targeted by the new emissions rules for reductions to the same levels as gasoline engines.
To make this drastic reduction in nitrous oxide levels possible, VW has developed new emissions-control technology, including a new catalytic converter which scrubs much of the NOx out of the exhaust gases—in fact, VW claims a 90% reduction in NOx from the previous-generation engine and exhaust system.
Volkswagen, along with Audi and DaimlerChrysler, is a member of the Bluetec group, a consortium of manufacturers collaborating on developing the next generation of diesel technology able to meet the tough new rules regarding emissions, as well as providing the diesel engine’s usual higher level of fuel economy relative to gasoline-powered engines.