Diesel

=Diesel=

The stereotypical conception of diesel is of a smelly, dirty fuel more popularly used in large vehicles like dump trucks more so than sedans. It's tailpipe emissions contain more soot and nitrogen oxide (NOx) than gasoline, contributing to smog and acid rain. However, technological advances have made diesel more suitable for all vehicles. And, offering up to 35% more mpg, diesel can be an attractive option (Newman). == Advances in the combustion process have cut NOx creation. New U.S. regulations have reduced the amount of sulfur, a traditionally noxious ingredient in diesel, form 500 parts per million to a paltry 15 parts per million. Refineries use hydrogen, which prefers to bond with sulfur, to extract the less desirable ingredient (Ashley).

Exhaust scrubbers have targeted particulate matter. Diesel particulate filters use a simple concept; they function as a trap which catches carbon soot, cutting down emissions 98%. Some filters are even self cleaning. Sensors detect when filters are becoming clogged, and increased fuel injection heats exhaust enough to burn off carbon caught in the filter (Ashley). Several methods for reducing NOx in exhaust are also in use. Some use different fuel injection strategies to cut down on the NOx created. Many use an ammonia-base fluid called urea which can convert NOx to nitrogen (Ashley).

DaimlerChrysler, Honda, and Volkswagen are the leading automotive industry proponents of diesel (Newman).

While the infrastructure exists to deliver diesel to consumer across the world using the same basic systems as gasoline pumps, production of diesel is a problem. Most U.S. refineries are designed to process gasoline, and a switch to diesel would be costly. In Europe, thanks to an earlier trend toward low sulfur diesels and government policies promoting diesel, many refineries are already equipped for diesel and in some regions 40% of cars purchased currently are diesels (Ashley).

Criticism
Critics of diesel say that new advances are unproven, and that diesel does little to decrease dependence on fossil fuels. They also note that diesel prices fluctuate more than gasoline, an inconvenience for consumers (Ashley).

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