Engine

An engine [ˈmoːtoːr] (also [moˈtoːr]; Latin mōtor 'mover') is a prime mover that performs mechanical work by converting a form of energy, such as thermal, chemical, hydraulic, pneumatic, or electrical energy, into kinetic energy.

As a rule, motors have a shaft which they rotate and through which they drive mechanical devices such as gears. Exceptions are rocket motors and linear motors. Today, internal combustion engines and electric motors are of paramount importance.

History of the engine

The earliest engines may have been smoke turbines for opening large doors around the year 100 Herons. Also, conjectures about the handling of Egyptian priesthood with hot gases for moving huge doors are plausible.

Around 1670, Ferdinand Verbiest is said to have built an operable model of a steam carriage in the service of the Emperor of China. The operating principle was based on the Herons ball, as had been the case with earlier smoke turbines. The vehicle is described in Verbiest's writings compiled into Astronomia Europea in Latin in 1681, where he first used the term engine in its modern sense. However, authentic illustrations of this vehicle do not exist.

The technical development of today's engines began with the steam engine invented by Thomas Savery and Thomas Newcomen and further developed by James Watt in 1778.

The steam engine changed the economic and social structures of Europe and triggered the industrial revolution. There were not only stationary machines, but after the invention of the high-pressure steam engine by Richard Trevithick, also the locomobile (a mobile, partly self-propelled steam engine for driving threshing machines or for steam ploughing), steam locomotives, steam ships, steam tractors and steam road rollers.

In 1816, Robert Stirling invented the hot gas engine that was later named after him. He was looking for a machine without the explosive boiler.

One of the first usable internal combustion engines - a gas engine based on the two-stroke principle - was invented by Étienne Lenoir, improved in 1862 by Nikolaus August Otto by developing the four-stroke principle and later named after him. The Otto engine was initially too large and too heavy to be fitted in an automobile. This problem was solved almost simultaneously by Gottlieb Daimler and Carl Friedrich Benz.

Even after the invention of internal combustion engines, the steam engine was still a much-used power source - cheap coal or wood could be used as fuel. However, due to their better efficiency and the high energy density of the fuels, internal combustion engines have since come to the fore, converting the chemical energy of the fuels inside them into thermal energy and then into mechanical energy.

For the future, the aim is to change the energy source of mobile engines in order to counteract the scarcity and thus increase in price of fossil fuels. This often also reduces emission levels. A prerequisite for this are practicable storage options for non-fossil energy sources, especially for mobile use (accumulators, alternative fuels). Electric motors and hybrid drives are possible alternatives to replace or supplement the piston engine.

In all sizes, from toys to industrial plants, electric motors for direct current, alternating current and three-phase current are used (electrical machines). Many electric motors - especially those with permanent magnets - can also work as generators when driven mechanically.

Requirements for motors

Engines and other prime movers convert chemical, electrical or thermal energy into mechanical energy (work). From a modern point of view, they should

1. have a high efficiency - i.e. use the fuel optimally and therefore with low consumption,
2. cause few emissions or at least emit few pollutants,
3. develop the highest possible performance with the lowest possible weight,
4. have high operational reliability and a long service life
5. and have other special properties depending on the application.

At the beginning of the engine construction stood - practically with each of the basic principles - the achievement of the necessary achievement. Other parameters of engines besides the power (consumption of electricity or fuel and mechanical power output) are the mass, the speed and the efficiency.