Audi could be taken to court by Daimler for BlueTec Technology infringement.

Audi has confirmed talks with Daimler AG, in response to a patent infringement dispute on Mercedes BlueTec technology, which allows diesel engines to produce lower carbon dioxide emissions.
Daimler is currently investigating if Audi has in fact been using the technology behind BlueTec without Daimlers permission. Since the two German automakers are in talks further litigation is unknown at this time.