The following cars represent the most technically advanced available.
The 2014 Volkswagen Jetta TDI offers basic transportation at a bargain and an excellent engine, but techies will want to hold off for the improved 2015 model.
Brian Cooley runs down a list of the five brawniest four-cylinder engines in cars today.
The 2014 Audi A7 TDI includes some of the best connected tech available today in an automobile, and those inclined to put up with a few diesel drivetrain quirks will be rewarded with significantly higher fuel economy than from the gasoline equivalent.
Despite some very minor quibbles, the 2014 BMW 535d xDrive delivers exceptional quality and feature content on all fronts, from online cabin tech to fuel economy to driving satisfaction.
The 2014 BMW 328d xDrive Sports Wagon combines 40+ mpg diesel efficiency, the flexibility of a wagon, and the thrills of a driver's car.
General Motors on Friday opened a new $200 million diesel engine plant in Rayong, Thailand. The plant is GM's most significant power-train investment in Southeast Asia to date.
With diesel fuel economy and its wagon format, the 2013 Volkswagen Jetta Sportwagen TDI offers great utility, and adds a premium-car feel, but cabin electronics only cover the basics.
Featuring excellent fuel economy and a generally comfortable and easy-driving character, the 2013 Mercedes-Benz GLK250 makes for a useful all-around vehicle, good for the daily commute and family road trips.
BMW considers which models to offer as four cylinder diesels in the U.S.
With solid cabin tech, the 2014 Chevrolet Cruze Diesel competes well with compact sedans and gets stellar fuel economy, but high initial cost and the price of diesel eat into the savings.