The Arrival of Clean Diesel
Say goodbye to the image of Mack trucks belching a large black cloud of exhaust wherever they go. With the arrival of "clean" diesel at US pumps, and the development of power-boosting and exhaust-scrubbing technologies, diesel-powered passenger cars are cleaner than their gasoline counterparts on just about all emissions - and run at a higher fuel efficiency.
Because what's under the hood of a diesel-powered passenger car in the 21st century is a far cry from the monsters that my dad used to wrestle. (Literally. He used to say, snuffing my trucking dreams, that I didn't have the upper body strength to make a truck go around the corner. He was right back then, but driving a diesel car now is no longer a wrestling match, thanks to power steering). Also, the fuel itself has become cleaner.
Wait: Isn't diesel what's left of petroleum after you take out the gasoline, the kerosene, and the stuff from which shampoo, fertilisers, and all manner of plastics are made? How can the rest possibly be "clean"?
It's still diesel. It still contains benzene, toluene and other organic compounds that aren't good for you. But when most of the sulphur has been taken out, to a level of 15ppm or lower, you can call it "Ultra-low-sulphur diesel" or ULSD for short. And because nobody can remember the acronym, or might confuse it with either a university or a psycho-active drug (and because it sounds so green), it's known as "clean" diesel.
On all but one emission (that of NOx), a diesel-powered car is actually cleaner than the gasoline version of similar power. The carbon footprint is smaller. And between turbocharging at the front end of the engine, and soot filtering at the back end, the particulate matter emerging from a diesel car's exhaust is lower than that of a gasoline-driven car of similar power.
Last summer we rented a diesel-powered car. It behaved like a car, not a Mack truck. It was zippy. Best of all, we stopped at the pump only once, at the end of a two-week trip. It had done 44 mpg.
More details at the original post.