Diesel Engine

"he steam engine was the driving force behind the Industrial Revolution in the United States and Europe during most of the nineteenth century. Toward the end of the nine- teenth century, however, it could no longer meet the needs of all industries, particularly smaller businesses. Steam engines were very large, making them best suited for heavy industry and transportation. They required an external firebox to burn fuel, a boiler to store the steam that drove the piston, and a condenser to turn the steam back into water. Steam engines required constant tending by an oper- ator and were highly inefficient. The average steam engine converted only 6% of its fuel heat into usable power. Internal combustion engines filled the need for a small, efficient power source. In an internal combustion engine , fuel burns inside the engine itself, rather than in a separate furnace or firebox. Higher working pressures are also possible when air and combustion gases are used instead of steam to propel the piston inside the cylinder. The gasoline engine and the diesel engine are the two most widely used internal combustion engines in the world. Credit for their invention is historically given to two men— Nikolaus Otto for the gasoline engine and Rudolf Diesel for the engine that bears his name. However, the tri- umphs of Otto and Diesel would not have been possible without the theories and experiments of earlier inventors and scholars. The fact that both Diesel and Otto faced challenges to their patents (Otto’s patent was eventually broken) proves that many people were working toward the same goal. Early Theories and Successes Nicholas Sadi Carnot, a French scientist, formulated theories on the thermodynamics of engine operation that would influence both Otto, and to a greater extent, Diesel. In papers published in 1824, Carnot introduced the idea of a cycle in heat engine operation. The cycle consisted of a series of steps that would both produce power and return the engine to its original position. Carnot theorized that a piston could be driven back and forth in a cylinder by first heating and then cooling a gas trapped inside the cylinder. The controlled expansion of the gas as it is heated and the contraction of the gas as it cooled would drive the piston."