The invention of the internal combustion engine is most probably the result of the developments of several individuals. Around 1780, Dutch scientist Christiaan Huygens built an engine that used gunpowder as a fuel, but this engine was far too dangerous to be practical. His assistant, Denis Papin, also experimented with developing an internal combustion engine, building a simple steam-powered device around 1790. Again, this engine was not practical, and not until the early nineteenth century did the development of a practical internal combustion engine become the quest of numerous inventors.
Before then, the steam engine was the power plant of choice. By 1770, the steam engine had been developed to the point that the French engineer Nicolas Cugnot used one to successfully propel a three-wheeled vehicle, and steam power reigned supreme in industry for nearly a century.
Early in the industrial revolution, inventors struggled to develop an engine in which compressed fuel could be burned within a cylinder housing a piston, thus capturing a much greater amount of the potential energy of the fuel. French physicist Nicholas Carnot (1796-1832) published a book in 1824 in which he set out the principles of an internal combustion engine which would use a flammable mixture of gas vapor and air.
Basing his work on Carnot's principles, another Frenchman, Jean-Joseph-Éttien Lenoir, presented the world with its first workable internal combustion engine in 1859. Lenoir's motor was a two-cycle, one-cylinder engine with slide valves and used illuminating gas (coal gas) as a fuel; it also used an electrical charge, supplied by a battery, to ignite the gas after it was drawn into the cylinder.
Lenoir sold several hundred of his engines, and he adapted his engine to power a carriage; consequently, he is credited with inventing the first gas-powered automobile. Lenoir's primitive two-stroke design, however, was inefficient because each back-and-forth motion of the piston must draw in the fuel, burn it, and expel the burnt gases.
Another Frenchman, Alphonse Beau de Rochas, recognized the shortcomings of Lenoir's engine, and, in 1862, he proposed refinements to the two-stroke cycle as well as designs for a four-stroke engine that would overcome many problems associated with the gas engines of the time.
The four-stroke engine doubles the motion of the piston required to accomplish intake, compression, and exhaust, and, by doing so, greatly increases the efficiency of the engine. Early French theory and practice were combined by two Germans, Nikolaus Otto and Eugen Langen, into a two-cycle engine that was considerably more efficient than the Lenoir engine. Introduced in 1867, Otto and Langen's engine achieved greater efficiency by compressing the gas before combustion, a refinement lacking in Lenoir's engine.
The two Germans' first workable four-stroke internal combustion engine was patented in 1876 and was tremendously successful, selling over 50,000 engines in the 17 years following its introduction. The "Otto-cycle" four-stroke engine was the development that made modern automobiles, aircraft, motorcycles, and other vehicles practical.
Gottlieb Daimler, who once worked for Otto, made several refinements to Otto's engine. He devised a cam system so that engines with more than one cylinder could be ganged together. Daimler's two-cylinder gas engine was built in a "V" shape, and he is credited with this innovation. Although supporters of Karl Benz and others disputed his claim, Daimler is also credited with developing the first internal combustion engine to burn gasoline--not coal gas--as its fuel, a development made possible by the invention of the carburetor by his partner, Wilhelm Maybach.
The internal combustion, piston engine has been developed into various configurations: "in-line" engines with 2, 4, 5, 6, or 8 cylinders; the "V"-shaped engines with 2, 4, 6, 8 or more cylinders; engines with two opposing pistons for each combustion chamber (used in Henry Ford's first car); multi-cylinder opposed piston engines; and engines with an odd number of cylinders arranged radially that are used extensively in airplanes.
In addition to piston-driven, gas-powered internal combustion engines, other internal combustion engines have been developed, such as the Wankel engine and the gas turbine engine. Jet engines and diesel engines are also powered by internal combustion.
Future developments of the internal combustion engine are being driven by new technology, methods of reducing pollution, and the search for lower production costs. The French Variable Combustion Ratio (VCR) engine and the Peristaltic Vane engine (a rotary engine design) both show promise. Bernard Condamin developed the VCR from his perception that engines are costly because so many different kinds are needed. The VCR adjusts combustion chamber volume to load so the engine operates efficiently in a variety of different applications.
The engine is small in size, and, because of its range of uses, it can be mass-produced for greater economy. The Peristaltic Vane engine, invented in the U.S. by Leo Kull, also has variable volume pressure chambers but uses sets of concentric, synchronized vanes in a rotary engine format. The rotary engine operates quietly, weighs little relative to the horsepower it produces, and is simple to construct.
Technological developments on the horizon include direct injection engines that burn a lean mixture of gasoline and air and produce fewer pollutants. Ultimately, the solution to the challenges of improving the internal combustion engine may rest in hybrids or combinations of effective inventions.