Motor Company's Volvo
unit wants to launch a diesel car
in the U.S. by the end of the decade. The challenge is meeting the stringent emissions standards, which are focused more on regulating oxides of nitrogen in North America. The European Euro 5 standards, the upcoming standard for European vehicles
, are more focused on reducing carbon dioxide, where diesel
engines have a clear advantage due to their lower fuel consumption. To meet both standards simultaneously with one emission system requires most likely the use of a urea injection system. While urea systems effectively clean up the nitric oxide emissions, they do require periodic filling, a concern to the EPA
. Current urea systems under development by DaimlerChrysler require filling every 12,000 to 15,000 miles, which means the fill-up could be done during routine oil changes
Note, the article
claims nitric oxides are the black soot coming out of diesel engine exhaust, which is definitely incorrect. Nitric oxides are the precursor of smog, but they are not the soot emissions people associate with diesels. Most modern diesel engines produce very little smoke, due to very high injection pressures. The little smoke that is formed is generally cleaned up with a diesel particulate filter.