Rudolf Christian Karl Diesel (1858–1913), a German thermal engineer, invented the diesel engine and patented it in 1893. Unlike their gasoline counterparts, which ignite an air/fuel mixture using spark plugs, diesel engines compress air to a very high pressure and then inject the fuel. The fuel then ignites due to the high temperature of the compressed air. Diesel engines are relatively fuel-efficient engines commonly used in heavy construction equipment, ships, locomotives, commercial trucks, and some large pickups, as well as in the production of electricity at some power plants or in factories.

Diesel-powered automobiles gained popularity in the United States during the oil crisis of the 1970s because they tend to result in better fuel economy than their gasoline counterparts. But diesel-powered cars have declined in popularity with American drivers since their peak in the mid-1970s because of quality-related problems in early models and because earlier diesel engines did not accelerate as quickly as those powered by gasoline. Diesel passenger cars have also declined in popularity because they are more expensive and they emit more smog-forming pollutants and toxic soot than other conventional internal-combustion engines. For eighteen-wheel trucks and other large vehicles, however, diesel engines are currently the standard.

Internet Resource

"How Diesel Engines Work." Available at http://auto.howstuffworks.com/diesel1.h tm.