Clean diesel has been dinged by the Volkswagen emissions-cheating scandal. But will the VW revelations do more than just sully the powertrain's short-term reputation in the U.S.? Proponents of diesel say the scandal won’t kill diesel here, as they point out that more than a dozen diesel models will arrive in the next year. But VW and Audi account for most: Last year, 138,174 such vehicles were sold in the U.S., and 68% were from the Wolfsburg, Germany automaker.