Volkswagen's Passat TDI, which was first introduced for the 2012 model year, offers an affordable mid-size sedan with a 2.0L four-cylinder diesel engine with excellent fuel economy (an EPA-rated 40 mph highway) and a range of well over 600 miles from the more than 18-gallon tank. The Passat is now VW's top fleet vehicle. View our photo gallery of the 2014 Passat TDI, and read our driving impressions blog post here. Photos by Vince Taroc.