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(motor), a machine that converts any kind of energy into mechanical work. Depending on the type of engine, the work may be produced by a rotor, a reciprocating piston, or a reaction device. Engines are used to drive machine tools and vehicles used in land, water, and air transportation, as well as in space travel, and to operate industrial, institutional, and domestic appliances.
Engines that directly convert the energy obtained from a natural source (such as fuel, wind energy, or water energy) into mechanical energy are called prime movers (steam, wind, or hydraulic engines). The largest group of prime movers are the heat engines, which use atomic energy or the chemical energy of fuels. Engines that convert the energy produced by prime movers into mechanical energy are called secondary engines (for example, electric motors, compressed-air motors, and some types of hydraulic motors). Devices that release stored mechanical energy are also classified as engines (for example, inertial, spring-driven, or weight-driven mechanisms). According to their purpose, engines may be classified as stationary (that is, mounted in a fixed position), movable (used in mobile machines), and vehicular (used in various means of transportation).
The first engine in the history of mankind was the water-wheel, which was used in irrigation systems in the countries of the ancient East and in Egypt, China, and India. During the Middle Ages, waterwheels were used in Europe to supply power for the manufacturing industry. Wind motors were also widely used during that period. Attempts to create a perpetual-motion machine date to approximately the 13th century.
The transition to machine technology, which began in the mid-18th century, required the development of engines that were independent of local power sources (such as water and wind). The first engine using the thermal energy of fuel was a steam-atmospheric piston engine operating in the intermittent mode. This engine appeared toward the turn of the 18th century. It was designed by the French physicist D. Papin and the English mechanical engineer T. Savery and was later improved by T. Newcomen in England and by M. Triewald in Sweden. Steam-atmospheric engines were not widely used. A design for an all-purpose steam engine was proposed in 1763 by the Russian mechanical engineer I. I. Polzunov, whose two-cylinder design provided continuous operation. In 1784 the English mechanical engineer J. Watt perfected a fully developed all-purpose heat engine. The introduction of steam engines led to the geographical separation of manufacturing industries from the locations of natural energy sources and resulted in the accelerated growth of industry. By 1880 the combined power of all steam engines used in the world’s industry exceeded 26 million kilowatts (kW), or 35 million hp.
Further improvements in supplying power to industry were achieved in the second half of the 19th century. During this period two new types of heat engines were invented—the steam turbine and the internal-combustion engine. Steam turbines became widely used after 1884 (patents by the English scientist C. Parsons and the Swedish inventor C. de Laval). In steam turbines the energy of steam is converted into the energy of a rotating shaft without a crank and connecting-rod assembly. The use of steam turbines opened up broad prospects for increasing the unit power. The turbine has become the basic engine used in large electric power plants. In the 1920’s the power ratings of steam turbines began a continuous increase, reaching 120 MW by the 1960’s.
The first usable internal-combustion engine was built in 1860 by the French mechanical engineer E. Lenoir. In 1876 in Germany, N. Otto invented an improved, four-cycle gas engine. The internal-combustion engine was simpler and more compact than the steam engine, since it did not require a steam boiler. In addition, the efficiency of internal-combustion engines was higher than that of steam engines. In 1867 the German engineer R. Diesel, who was working on improving the efficiency of engines, proposed an internal-combustion engine in which the ignition would be accomplished by pressure. A further improvement in this type of engine made it possible to use cheap oil as a fuel. Consequently, this type of internal-combustion engine came to be used as an economically advantageous stationary motor. At the same time, the internal-combustion engine began to be widely used for transportation. In the 1960’s about 80 percent of the total power of all existing engines was used in transportation. For example, the total power of motor-vehicle engines in all countries of the world exceeds 11 billion kW (15 billion hp).
Parallel with the development of heat engines, progress was also made in improving the design of hydraulic prime movers, particularly turbines (designs by the French engineer B. Fourneyron and by the American A. Pelton and the Austrian B. Kaplan). The creation of powerful hydraulic turbines facilitated the construction of hydraulic power units with ratings as high as 600 MW. Large hydraulic power plants were built on large rivers or waterfalls.
The invention and introduction of electric motors was an extremely important step in the development of power sources for industry. In 1831 the English physicist M. Faraday discovered the phenomenon of electromagnetic induction, and in 1834 the Russian scientist B. S. Iakobi constructed the first practical DC motor. However, it was not until the 1870’s, with the availability of inexpensive sources of electric power (DC generators), that DC motors came into widespread use.
At the same time, the design of electric motors was being improved by the electrical engineers A. Pacinotti in Italy and Z. Gramm in Belgium. In 1888–89 the Russian engineer M. O. Dolivo-Dobrovol’skii constructed a three-phase asynchronous squirrel-cage motor. In subsequent years the design of electric motors was improved. Electric motors were built in a wide range of power ratings—from fractions of a watt to dozens of megawatts. Asynchronous electric motors are easy to manufacture and reliable in operation, which has led to their wide acceptance in industry. In the 20th century electric drive became a prime factor in the development of power engineering and brought about the gradual division of the field into two independent systems. The prime movers (for example, turbogenerators and hydraulic generators) are mostly concentrated in steam and hydroelectric power plants, whereas electric motors form a parallel system of terminal current receivers installed in various kinds of energy-consuming establishments that serve the national economy. Electric motors are also widely used in domestic appliances, such as sewing machines, washing machines, cooking devices, refrigerators, and electric razors.
In the first half of the 20th century some new types of practical heat engines were constructed—for example, the gas turbine, the jet engine, and the nuclear power plant. The gas turbine became the mainstay of aircraft power-plant construction; it is also finding increasingly broad application in locomotives and motor vehicles. Jet engines make it possible to obtain an extremely high unit power rating. In 1961 the total power of the rockets that put into orbit the first Vostok spacecraft, piloted by Iu. A. Gagarin, was 14 million kW (approximately 20 million hp). This amount of power is approximately equal to the total rated power of all the electric power plants in the USSR in 1948. The power of the Proton satellite launch vehicle (1965–68) exceeded 45 million kW (about 60 million hp).
In the industry of the USSR more than 85 percent of the power is concentrated in electric motors and installations. In agriculture, the internal-combustion engine accounted for about 90 percent of total power (1968). The total power used by the nation’s economy in the USSR is growing continuously. The combined power of all engines and motors manufactured in 1967 was 1.8 times greater than the corresponding figure for 1960. The 1967 figures were 14.7 million kW for steam and hydraulic turbines and 11 million kW for diesels (not including tractors). More than 5 million electric motors, with a total power rating of 30 million kW, were also manufactured in 1967.
Combinations of various types of engines are used to provide complex operating conditions. For example, steam turbines may be installed in combination with internal-combustion engines or gas turbines. Designs have been developed that combine a jet engine and a liquid-propellant rocket engine (for example, turbine-rocket and rocket-ramjet engines).
The future development of engines depends on the growth of power systems, on the integrated mechanization and automation of production, on the improvement of transportation, and on the future of space exploration. The power of the prime movers in electric power plants is increasing continuously, the design of the engines is being improved, and work is being conducted on the creation of thermonuclear fusion external-combustion engines, and new types of rocket engines (ion, plasma, and photon engines). Important work in the field of transportation engine design is proceeding in the direction of creating economical rotary pistonless and rotary-piston engines (for example, the Wankel rotary combustion engine). Electric motors suitable for automobiles, as well as small-scale atomic engines, are also under development. In other countries (for example, the USA), work is being done on combining an external-combustion engine with an electric motor for use in motor-vehicle transportation. The most important trend in power engineering in the second half of the 20th century has been direct conversion of the thermal and chemical energy of fuels into electric current with the aid of fuel cells and magnetohydrodynamic generators. The development of atomic power engineering, jet-engine technology, and machineless current generators in conjunction with high-powered engines will open new prospects for the use of the productive powers of human society.
A. A. PARKHOMENKO
What does it mean when you dream about an engine?
If we do not normally work on or around engines, a dream about an engine can represent our vitality or our drive. The body considered as a machine, particularly the heart.
A machine designed for the conversion of energy into useful mechanical motion. The principal characteristic of an engine is its capacity to deliver appreciable mechanical power, as contrasted to a mechanism such as a clock, whose significant output is motion. By usage an engine is usually a machine that burns or otherwise consumes a fuel, as differentiated from an electric machine that produces mechanical power without altering the composition of matter. Similarly, a spring-driven mechanism is said to be powered by a spring motor; a flywheel acts as an inertia motor. By definition a hydraulic turbine is not an engine, although it competes with the engine as a prime source of mechanical power. See Energy conversion, Hydraulic turbine, Motor, Prime mover
Traditionally, engines are classed as external or internal combustion. External combustion engines consume their fuel or other energy source in a separate furnace or reactor. A further basis of classification concerns the working fluid. If the working fluid is recirculated, the engine operates on a closed cycle. If the working fluid is discharged after one pass through boiler and engine, the engine operates on an open cycle. The commonest types of engine use atmospheric air in open cycles both as the principal constituent of their working fluids and as oxidizer for their fuels. See Diesel engine, Gas turbine, Internal combustion engine, Nuclear reactor, Rotary engine, Stirling engine, Turbine propulsion
2. An analogous piece of software; notionally, one that does a lot of noisy crunching, such as a "database engine", or "search engine".
The hackish senses of "engine" are actually close to its original, pre-Industrial-Revolution sense of a skill, clever device, or instrument (the word is cognate to "ingenuity"). This sense had not been completely eclipsed by the modern connotation of power-transducing machinery in Charles Babbage's time, which explains why he named the stored-program computer that he designed in 1844 the "Analytical Engine".
engine(1) A specialized processor, such as a graphics processor. Like any engine, the faster it runs, the quicker the job gets done. See graphics engine and printer engine.
(2) Software that performs a very specific and repetitive function in contrast to an application that has many functions offered to the user. For example, a "search engine" or "database engine" responds to user queries over and over again. An "SMTP engine" forwards mail. A "dictionary engine" looks up words. A "rendering engine" forms the text and images that are displayed and printed. See search engine, database engine and rendering engine.