To many car buyers, the green colored gas pump handle at the filling station is still a mystery. But that's the pump for the diesel -- a fuel for a growing number of family cars and SUVs. Indeed, more and more car buyers are choosing diesel for both fun and fuel economy.

Chevy this year will launch a diesel version of the popular Cruze sedan. Jeep recently said it's considering a diesel engine for the Wrangler. And Mazda will soon be marketing a diesel version of its Mazda6VolkswagenBMWMercedes and Audi have been offering them for some time in the U.S. and Europe and are planning more models for America.

What is clean diesel? It's Ultra Low Sulphur Diesel, to be exact, and it's a cleaner, more refined fuel than diesel sold before 2007. With lower sulphur, it has less particulates, and thus lower soot coming out of the tail-pipe.

Why do we want it? While the price of diesel in the U.S. is typically higher than gasoline prices, diesel engines get 20 percent to 40 percent better fuel economy than comparable gasoline cars. AOL readers, for example, repoirt getting 49 mpg on the highway with the 2013 Volkswagen Passat TDI on a regular basis.

What else is good about diesel? In a word, power. Step on the pedal of a Volkswagen Jetta diesel or the new Cruze diesel, and you might think you had the power of a V6 engine even though there is just a 2.0 liter four-cylinder under the hood. Also, modern diesel engines have a track record for long, long life. It would not be out of the ordinary at all to get more than 200,000 miles and up with a diesel assuming proper maintenance.

The downside?If you really want to mess up a diesel engine, the best way to do it is to accidentally fill it up with regular or premium gasoline and then drive off. That will pretty much kill it. And a gasoline engine doesn't want diesel fuel in it either. Its ruinous. But the diesel nozzle is bigger than the hole in most gas-powered cars on the road, so its not likely to happen.

Take a look at out write-ups on some of these clean diesel cars and crossovers/SUVs and see if you want to consider them on your shopping list.

Chevy Cruze Diesel

Chevy Cruze Diesel

Arriving at dealership this May as a 2014 model, the diesel version of the Cruze will have a fuel economy rating of 42 mpg, about the same as the gas-powered Cruze Eco, but with a lot more power and driving enjoyment.

The Cruze diesel will come with a 2.0 liter, turbo-charged diesel engine that produces 148 horsepower, but 258 pounds-feet of torque. That's your power. Torque is the amount of power the car produces at low revolutions. So, when you are driving onto a highway on an on-ramp, for example, or trying to pass another car, there is plenty of get-up-and-go. Newbies to driving a diesel are often surprised at how powerful the engine feels.

GM is asking $25,695, plus an $810 destination fee. That marks a $2,115 premium over a loaded Cruze LTZ Auto and $2,640 more than the Jetta TDI, though the MSRP will net you a leather interior, 17-inch alloy wheels and an Aero Performance Package, as well as a two-year maintenance plan and five-year, 100,000-mile powertrain warranty.

Mazda6 diesel

Mazda6 diesel

The Mazda6 Skyactiv-D diesel will be out with a 2.2-liter clean-diesel engine under its hood in the second half of 2013.

It will be available with either a six-speed manual or automatic transmission, and official fuel economy estimates are still pending. But the highway fuel economy rating could be as high as 60 mpg. That would surely be more than enough to off-set any of the typical spreads in price between gasoline and diesel.

Volkswagen Passat TDI

Volkswagen Passat TDI

Can you name a fun-to-drive sedan with a manual transmission that can transport five adults and their luggage comfortably while sipping fuel at the rate of 50 mpg? The answer is the Volkswagen Passat TDI.

The turbocharged, direct-injected, 2.0-liter inline-four cylinder is only rated at 140 horsepower, but it delivers 236 pound-feet of that torque we talked about, which gives it lots of power off a standing start.

The government rates this car 31 mpg city and 43 mpg highway. But our testers get 35 mpg and 50 mpg. With an 18.5-gallon fuel tank, stops at the filling station are few and far between.

Our recent test car stickered at $27,020.

Volkswagen Jetta TDI

Volkswagen Jetta TDI

Volkswagen has long offered the most diesels outside of trucks. Indeed, you can buy TDI versions of the PassatGolfBeetleTouareg and, of course, Jetta. The Jetta is the workhorse of the VW showroom.

Pricing for the 2013 Jetta TDI sedan starts at $22,990. The SportWagen TDI has a sticker price starting at $25,540, the same as last year. EPA estimated fuel economy for both models is 30 city/42 highway and 34 combined.

The 2012 Jetta TDI, which we had in our long-term test fleet had a problem with stalling. But we believe VW has remedied that for the 2013 model year vehicles on sale now.

Mercedes-Benz E350 Bluetec

Mercedes-Benz E350 Bluetec

When we tested this vehicle last year, we registered over 30 mpg. That's a big deal among luxury sedans.

We got as high as 35 mpg on highway driving. Sure, the engine only produces 210 horsepower, but with all that butt-lifting low-end torque we keep talking about, who cares? Pulling away from a stop-light, the driver has the feeling of being launched.

The premium buyers pay for the diesel over has been only about $1,250, which puts the price at $52,200. We expect that to stay about the same when the all-new E Class debuts this year in dealerships. The E Class packs all the Mercedes quality you expect.

But beware, that options add up fast with either the gasoline or Bluetec versions. It's easy to tack on about $10K in goodies after you fit it out the way one would naturally want it.

Audi Q5

Audi Q5

Audi has offered a diesel version of its Q7 SUV for a few years now, but it is adding diesel versions of its Q5A6A8 and A7 as well this spring.

The Q5 is already a terrific luxury crossover sporting excellent interior craftsmanship, braking and sporty handling.

The TDI version should draw a good number of Audi enthusiasts as it will only enhance the driving experience with a 30 percent bump in fuel economy. We expect to be able to drive on of these off the lot for around $40,000 to $42,000, which will make it one of the best values around in the luxury space.

BMW X5 xDrive35d

BMW X5 xDrive35d

The X5 xDrive35d remains the fastest and most fuel efficient vehicle in its category. It accelerates from 0 to 60 in 6.9 seconds with fuel economy ratings of 19 mpg city/26 mpg highway/22 mpg combined.

While we love the X5 as a driver, those fuel economy numbers are at the low end of what kind of advantage a diesel engine can provide. Sure it's an improvement over the gasoline-powered X5 fuel economy. But frankly, we have a hard time getting excited over any hybrid or diesel that doesn't push the vehicle down a highway at better than 30 mpg.

The X5 is a larger vehicle, with added weight of an all-wheel-drive system, though, so if this is the kind of vehicle you want and need then the diesel version not only improves your fuel economy but it also delivers all that low end torque in an all-wheel drive package. That makes it a champion driver in all manner of weather.

The price premium for the X5 diesel over the standard version is considerable: $9,000, to put the start price at $56,700, but that includes features and equipment not included on the base model.