A Guide to Diesel & Clean Diesel Cars

What Is A Diesel Vehicle?

A diesel vehicle uses an engine that has a different combustion cycle than a gasoline engine. In a gasoline engine, fuel is mixed with air, drawn into the cylinder, and ignited by a spark plug. In a diesel, air is drawn into the cylinder and compressed first without fuel present. This compression heats the air to such a high temperature that when fuel is then injected into the cylinder, it combusts.

By using higher compression ratios and higher combustion temperatures, diesels operate more efficiently. As a result, diesel vehicles attain better fuel economy than their gasoline counterparts. This fuel economy advantage is enhanced by the fact that a gallon of diesel fuel contains about 10 percent more energy than a gallon of gasoline. These two factors help modern direct-injection diesels achieve roughly 50 percent higher fuel economy than their gasoline counterparts.

Diesel vehicles now account for nearly half of all new vehicle sales in Europe. In some European countries, such as France, diesel vehicles account for as much as 70 percent of new car sales. Diesels represent about 3 percent of today’s new car market. J.D. Power, a market research firm, predicts that diesel will rise to 11.5 percent by 2015—rising at a higher rate and to a higher level than gas-electric hybrids. Mercedes, Volkswagen, and Chrysler are the key players in the diesel market.

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The List of Diesel Cars

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Diesel-Hybrid Dreams

Biodiesel

Biodiesel is an alternative fuel used in diesel engines. Biodiesel, in its pure form, is not made from petroleum; instead, all or part of it is derived from plant oils or animal fats. In the United States, most commercial biodiesel is made from soybean oil, while in Europe, rapeseed (canola) oil is more commonly used. Biodiesel can be made from virgin oil, or from used cooking oil recycled from restaurants and food processing operations.

Biodiesel is a renewable fuel; to make more, we just grow more of the crop needed. It can be produced domestically, displacing imported petroleum. Biodiesel should not be confused with straight vegetable oil, which is untreated oil that some people use as fuel in their modified diesel cars. Biodiesel is a more standardized product that can be used in most diesel engines without any modifications. Like conventional diesel fuel, biodiesel can only be used in diesel engines; today’s hybrids with their spark-ignition, gasoline engines cannot burn biodiesel.

Unlike any other fuel for modern engines, biodiesel can be made at home without investing heavily in special equipment or earning a degree in chemistry. Many who make their own biodiesel use waste cooking oil as the base fuel, and restaurants are often happy to provide it to them free of charge. Other components for the reaction must be purchased, and time is required to master the production process. Once a user is experienced in making biodiesel, the per-gallon cost can be extremely low. Perhaps even more satisfying than the low cost is the knowledge that using biodiesel puts nothing in the coffers of major oil companies or major oil-producing nations and, in many cases, reuses oil that would otherwise be discarded.

Using pure biodiesel (B100) instead of conventional diesel significantly reduces emissions of hydrocarbons, carbon monoxide, and particulates, as well as output of carbon dioxide. Unfortuntately, EPA tests show that using B100 instead of conventional diesel results in 10 percent higher emissions of oxides of nitrogen, which can contribute to smog.

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