Gas prices are soaring, and suddenly the 20 to 40 percent improvement in fuel economy is making diesel vehicles look much more attractive. Besides, the noisy, smelly, smoke-belching vehicles that gave diesel a bad rap in the '70s are gone. They've been replaced by fuel-efficient, clean-burning vehicles that offer more performance than their gasoline equivalents.

Although stringent emissions standards limit the number of diesel vehicles offered in the United States, several automakers are selling diesel cars today, and many others are considering bringing light-duty diesels to the States within the next few years. In this CNET quick guide, we discuss the history of diesel, where it is today, how a diesel engine works, and how it's influencing the future of the car industry.

Diesel 101

Diesel 101
Diesel engines used to be known for slow starts and sooty exhaust, but now you can expect to get great mileage without blackening the sky or being last off the line.

Diesel then and now
Diesel has been sitting on the sidelines for decades while gasoline became the dominant fuel. But diesel seems ready for the field.

Regulating the future
Carmakers respond tepidly to the diesel market in the United States, but there are indications they will step up production.