Back in November 2006, Mercedes-Benz
indicated that the three companies would be cooperating on promoting new clean diesels
using the same BlueTec aftertreatment technology. Within a few weeks BMW and, later, Volkswagen
made it clear they would not be using the BlueTec branding on their cars. BMW chose to call their system BluePerformance and Volkswagen and Audi are using CleanTDI or simply TDI. Nonetheless all three manufacturers are using the same technology in order to meet U.S. Tier2 Bin5 emissions requirements. All the engines use high-pressure common-rail fuel injection systems along with diesel particulate filters and urea injection systems to eliminate the soot and NOx emissions. The only exception is Volkswagen's smaller 2.0L four cylinder diesel which will use a maintenance-free lean NOx trap in place of urea injection.
As the three manufacturers race to get their first clean diesels to the U.S. market this fall it looks like Mercedes
may be filing a patent infringement suit against Audi over the BlueTec technology. It appears that under the original alliance Daimler may have wanted a licensing fee from BMW and VW/Audi. Mercedes has a European patent (EP1054722B1) that apparently covers some aspect of the NOx reduction. It's not known at this point exactly what the patent covers because the after-treatment systems are actually provided by suppliers like Bosch and Delphi. At this point it sounds like a lot of spite and it's anyones guess if this will affect the U.S. launch of the new diesels.
[Source: Auto Motor und Sport