maximus Posted September 5, 2005 GM leans toward urea injection to clean up diesel emissions RICHARD TRUETT | Automotive News Posted Date: 8/31/05 DETROIT -- General Motors is leaning toward a controversial emissions system, urea injection, that enables diesel engines to meet tough pollution standards in place for 2009. The technology, also known as selective catalytic reduction, is used on freight-hauling trucks in Europe. But the EPA questions the use of selective catalytic reduction because the driver must keep the vehicle from running out of urea. If the urea tank runs dry, the driver will notice no difference in performance. But the vehicle won't meet emissions standards for smog-producing oxides of nitrogen, or NOx. The stakes are huge for GM. Thanks mostly to the quiet, powerful and smooth-running Duramax diesel V-8 developed with Isuzu, GM says its share of the U.S. heavy-duty diesel truck market has ballooned from about 2 percent in 1999 to more than 25 percent today. The diesel-powered Chevrolet Silverado and GMC Sierra pickups are among the few GM vehicles that sell without profit-eating incentives. The automaker expects to sell about 200,000 diesel-powered trucks in 2006. Decision within a year GM officials say they will decide in the next 12 months whether to install the urea injection system on heavy-duty diesel trucks in North America. The alternative, a filter in the exhaust system called a lean NOx trap, also is being evaluated by GM. But David Brown, a General Motors staff engineer in Milford, Mich., who works on advanced propulsion systems controls, says the lean NOx trap uses expensive precious metals and has not been proven to meet EPA requirements of 10 years and 150,000 miles. Asked about the chances of GM using selective catalytic reduction, Brown said: "I think they are better than 50-50." Selective catalytic reduction is cost-effective and meets durability requirements, he said. Acid into the exhaust pipes The urea injection system works by shooting an ammonia-like acid into the exhaust pipes, radically reducing NOx. Because engineers need two to three years to design, develop, integrate, test and validate an emissions system, GM soon must decide which technology it will install. Starting in 2009, emission standards require diesel engines on heavy-duty trucks to run as cleanly as gasoline engines. If GM doesn't have a new emission system ready when the tougher rules go into effect, it could cost the company billions of dollars in lost sales on the Silverado and Sierra. Ford Motor Co. also is considering selective catalytic reduction and NOx traps. DaimlerChrysler AG recently confirmed that it will use selective catalytic reduction on its new generation of diesel models for the United States, which include sedans and SUVs. DaimlerChrysler also is considering diesel versions of the Jeep Grand Cherokee and Chrysler 300 sedan. Those, too, would be equipped with selective catalytic reduction. Share this post Link to post
VAXXi Posted September 5, 2005 Metre, te-ai inselat la titlu de data asta ... amarnic Nu functioneaza cu uree, ci injecteaza uree in esapament pentru a reduce emisiile de compusi de azot din gazele de evacuare. Evidentiez: The urea injection system works by shooting an ammonia-like acid into the exhaust pipes, radically reducing NOx. Si toate astea pentru ca motoarele Diesel sa fie la fel de "curate" precum cele pe benzina. Share this post Link to post
