By Umair Irfan and ClimateWire:

 In using the defeat device across an estimated 11 million cars around the world, Volkswagen’s engineers signaled their own defeat in the contest to make diesel a viable alternative for American consumers.
 Though it holds the promise of greater fuel efficiency, and therefore less carbon emissions, getting diesel right is difficult in passenger cars, especially in the United States. The problem stems from regulations and the diesel engines themselves.
 Engines that run on diesel fuel are inherently more fuel-efficient than their gasoline counterparts. Gasoline engines have only recently started hitting 50 mpg in fuel economy, and manufacturers have had to resort to making tiny, fuel-sipping econoboxes or hybrids that have an electric drivetrain glommed on to hit these target