With an increasing number of diesel passenger cars appearing in showrooms, car buyers have more options for fuel-efficient driving than they did only a few years ago.

After a brief hiatus several years ago, when new and tougher emissions standards came into effect for diesel vehicles, the number has steadily increased--and 2014 has a bumper crop of new diesel vehicles.

Two of the most important are the 2014 Chevrolet Cruze Diesel and the 2014 Jeep Grand Cherokee EcoDiesel, both of which add a diesel engine to an already popular vehicle sold in high volumes.

We've already covered every diesel car on sale in the U.S., but here's our guide to the debutantes among the group.

2013 Audi A8 TDI

2013 Audi A8 TDI

AUDI

This is Audi's year to expand its array of diesel vehicles, previously confined to the expensive and aging Q7 TDI large sport-utility vehicle.

For 2014, the company has added the Audi A6 TDI mid-size sedan, A7 "four-door coupe," and A8 TDI large luxury sedan, as well as a Q5 TDI compact crossover.

The three sedans all use a 3.0-liter V-6 turbodiesel, which puts out 240 horsepower and a substantial 406 pounds-feet of torque.

The mid-size A6 TDI gets a 29-mpg rating, with a starting price of $57,500.

The sleek, stylish A7 TDI comes in at the same 29 mpg combined, but adds an extra $9,400 to the starting price--making it your call if you want the extra $10K of style in your German luxury diesel sport sedan.

The large aluminum-bodied 2014 Audi A8 TDI is rated at 28 mpg combined by the EPA, and starts at $82,500.

Then there's the Q5 TDI crossover, which also uses the V-6 engine, and is rated at 27 mpg combined (24 mpg city, 31 mpg highway) at a starting price of $46,500.

For the record, that's $4,400 lower than the all-but-invisible Audi Q5 Hybrid, a rare beast indeed on U.S. roads.

All four of the new 2014 Audi diesels will be arriving in showrooms this summer.

2014 BMW 328d, 2013 New York Auto Show

2014 BMW 328d, 2013 New York Auto Show

BMW

This year marks the return of the BMW 328d, the diesel-engined version of BMW's 3-Series sport sedan--along with a new Sports Wagon model to sit alongside the four-door sedan.

The latest model for 2014, however, uses a 180-horsepower 2.0-liter four-cylinder turbodiesel that puts out 280 lb-ft of torque rather than the more powerful but thirstier straight-six turbodiesel in the previous generation of 335d 328d 3-Series diesel.

It powers the rear wheels through an eight-speed automatic transmission, and the combination is rated at 37 mpg combined, made up of a city rating of 32 mpg and a high 45-mpg rating in the EPA's highway cycle.

Add the xDrive all-wheel drive option, and those ratings fall slightly, to 35 mpg combined (31 mpg city, 43 mpg highway).

The first diesel 3-Series cars for 2014 will arrive at BMW dealers later this fall. The base 328d sedan with rear-wheel drive starts at $39,525; the xDrive sedan adds another $2,000 to that; and the Sports Wagon (only offered with xDrive) is priced from $43,875.

2014 Chevrolet Cruze Diesel

2014 Chevrolet Cruze Diesel

CHEVROLET

The 2014 Chevrolet Cruze Diesel is Chevy's first diesel passenger car in 28 years, and it's a bit of an experiment for the carmaker.

It's fitted with a 151-horsepower 2.0-liter turbodiesel four-cylinder engine, built in Germany and adapted from one that's the larger of two Cruze diesel options in Europe, where diesels take roughly half the total new-car market.

That engine powers the wheels through a six-speed automatic built by Aisin, and slightly tougher than the six-speed automatic used on all gasoline-engine Cruzes sold in the U.S.

The list price starts at $25,695, near the top of the Cruze range, but Chevy hopes the diesel Cruze will attract new buyers to the brand who might not otherwise have considered a Chevrolet compact sedan.

The EPA rates the Cruze Diesel at 33 mpg combined (27 mpg city, 46 mpg highway).

2014 Jeep Grand Cherokee - 2013 Detroit Auto Show

2014 Jeep Grand Cherokee - 2013 Detroit Auto Show

JEEP

The 2014 Jeep Grand Cherokee EcoDiesel marks a return of diesel engines to the Jeep brand after a hiatus of several years.

Sourced from Italy, where Chrysler's parent company Fiat has long experience with diesel engines, the 3.0-liter V-6 turbodiesel produces 240 horsepower and 420 lb-ft of torque in Jeep's popular sport-utility vehicle.

The EPA rates the diesel Grand Cherokee at 21 mpg city, 28 mpg highway when fitted with Jeep's four-wheel drive. If you opt for rear-wheel drive only, those numbers rise to 22 mpg city, 30 mpg highway.

2014 Ram 1500 EcoDiesel

2014 Ram 1500 EcoDiesel

RAM

The new 2014 Ram 1500 EcoDiesel pickup truck is the only light-duty (standard size) pickup truck offered in the U.S. market.

Chevrolet, Ford, and GMC all offer diesels in their heavy-duty pickup trucks, but Ram (formerly Dodge Truck) is the sole company to fit a diesel to its smallest full-size pickup.

The 1500 EcoDiesel uses the same 3.0-liter V-6 turbodiesel that's fitted to the Jeep Grand Cherokee EcoDiesel, along with the company's new eight-speed automatic transmission.

In its pickup truck guise, the clean diesel V-6 again puts out 240 horsepower and a substantial 420 lb-ft of torque.

That truck will go on sale later this year at Chrysler-Dodge-Fiat-Ram-SRT dealers, at a price $2,850 higher than a comparably equipped Ram 1500 with the Hemi V-8 gasoline engine.

Ram says owners can make back the higher purchase cost in fuel savings within three years, depending on how many miles the truck covers and the local price of diesel fuel.

2015 Volkswagen Golf, at 2013 New York Auto Show

2015 Volkswagen Golf, at 2013 New York Auto Show

VOLKSWAGEN

While VW has provided details of its new diesel engine range, there are no new models with diesels introduced for the 2014 model year.

Next year, however, will be a different story, when the all-new 2015 Volkswagen Golf TDI makes it debut.

There are other diesels coming as well, among them the highly anticipated first diesel from Mazda, which will fit its new SkyActiv-D diesel engine to its Mazda 6 mid-size sport sedan later this year.

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