Engine

A motor [ mo ː to ː r] ( also [ moto ː r]; Latin motor, mover ') is a machine that performs mechanical work by converting one form of energy, such as thermal, chemical or electrical energy into kinetic energy.

As a rule, engines are equipped with a shaft that will enable them to rotate and through mechanical devices, such as transmission power. Exceptions are rocket motors and linear motors. Today, internal combustion engines and electric motors are of paramount importance.

  • 4.3.1 Optimization of combustion engines
  • 4.3.2 compression-ignition ( diesel)
  • 4.3.3 an external igniter (petrol engine )
  • 4.3.4 Development and Future
  • 4.4.1 Efficiency and Applications

History of the motor

The earliest engines could have been 100 Herons smoke turbines to open large doors around the year. 1678 to Ferdinand Verbiest built a steam car in the service of the Emperor of China. Also assumptions for dealing Egyptian priesthood are plausible with hot gases to move huge doors.

The technical development to today's engines began to understand the process invented by Thomas Savery and Thomas Newcomen and James Watt in 1778 by advanced steam engine.

The steam engine changed the social and economic structures of Europe and triggered the industrial revolution. There was not only stationary machines, but after the invention of high-pressure steam engine by Richard Trevithick and the traction engine ( a mobile, partially self-propelled steam engine used to drive threshing machines or steam plowing), steam locomotives, steam ships, steam tractors and road rollers.

1816 Robert Stirling invented the later named after him hot-gas engine. He was looking for a machine without the hazardous boiler.

One of the first practical internal combustion engines - a gas engine according to the two -stroke principle - was invented by Etienne Lenoir, 1862 by Nikolaus August Otto improved by the development of the four-stroke principle and later named after him. The petrol engine was initially too big and too heavy to be installed in an automobile can. This problem solved almost simultaneously, Gottlieb Daimler and Carl Friedrich Benz.

Even after the invention of the internal combustion engine the steam engine was still a lot of unused drive - it was cheap coal or wood used as fuel. Due to their better efficiency and high energy density of the fuels combustion engines but have since come to the fore, which then convert the chemical energy of fuels in its interior into heat energy and mechanical energy.

For the future, aiming for a change of the energy source of mobile engines in order to cope with the shortage, and thus more expensive fossil fuels. Often, this reduces the emission values ​​. This requires practical storage capabilities of non-fossil energy sources, especially for mobile use ( batteries, alternative fuels). Electric motors and hybrid drives are possible alternatives to replace or complement the piston engine.

In all sizes, from toys to industrial plants, find electric motors for DC, AC and three-phase use ( electrical machinery). Many electric motors - especially those with permanent magnets - can also operate as generators when they are mechanically driven.

Requirements for motors

Engines and other combustion engines convert chemical, electrical or thermal energy to mechanical energy (work). They are from a modern perspective

At the beginning of Motorenbaues stand - practically at each of the basic principles - achieving the required performance. Further parameters of motors include power ( consumption of electricity or fuel and mechanical power ) nor the mass, the speed and the efficiency.

Overview of different types

  • Electric motor linear motor
  • Three phase asynchronous motor ( DASM )
  • Three-phase synchronous motor
  • Stepper motor
  • Servomotor
  • Universal motor
  • DC motor
  • Reluctance motor
  • Slip ring motor
  • Pole-changing motors
  • Three-phase linear motor
  • Shunt motor
  • Compound motor
  • Pony motor
  • Einphaseninduktionsmotor
  • Capacitor motor
  • Shaded pole motor
  • Kappel engine
  • Tubular motor
  • Pancake
  • Commutator
  • Stelzer engine
  • Reciprocating engine ( internal combustion engine or rotary engine as a stand ) gasoline engine
  • Diesel engine
  • This petrol engine
  • Hydrogen internal combustion engine
  • Hydrogen cycle engine
  • Opposed-piston engine
  • Hot bulb engine
  • Wankel engine A rotary engine ( a kinematic form of the Wankel engine )
  • Rotary engine (second kinematic shape of the Wankel engine )
  • Rocket engine
  • Jet engine
  • Ramjet
  • Pulse jet engine

Types of motors

Steam engine

The steam engine is the " Urmotor " the industrialization of the last centuries. It was invented by Thomas Newcomen. She works with hot steam under pressure. Its thrust is absorbed by the steam piston. In this case, a linear movement is converted via a crank drive into a rotary motion as the internal combustion engine. As early as 1850, there were several species of this piston engine.

Operation

Using a fire boiler in which a charcoal fire, the water is heated to boiling temperature or higher, the heated water generated expanding steam. This steam is fed via a mechanical control unit of the crank mechanism of the steam engine. The control unit causing the steam cylinder (in which the piston moves ) of the crank mechanism again only steam obtained when the expanded steam of the previous stroke - cycle has largely escaped.

Motion conversion

The linear movement of the piston in the expanding cylinder chamber, in the above, the water vapor was introduced is converted by a connecting rod to the crank or crank pin to a rotary motion. This process is continuously repeated. What dismisses the means of locomotion from the chimney or exhaust, the ejected steam the piston cylinder, mixed with the flue gases from the furnace.

Future

The steam engine was replaced by the combustion engine and can be viewed from today's perspective energetically deprecated. It has a low efficiency and thus has no future. If heat naturally occurring available as in Iceland (geothermal energy ), we will rather use instead of a stationary steam engine, the steam turbine, which even today has its place in a coal-fired power plant or nuclear power plant.

Steam turbine

It is the modern version of the heat engine and uses the steam power with higher efficiency. Vapor pressure drives a turbine, the rotation principle, quieter operation than the back and forth of a steam piston. The torque curve is therefore shallow, which means it operates more smoothly.

Combustion engines

With the invention of the automobile at the end of the 19th century, internal combustion engines have been used in many engineering. These convert the liberated during the combustion heat on volume change work to mechanical work in thermodynamic cycles. The pressure of the combustion gases on the surface of a movable member ( piston ) which is reacted via a crank mechanism ( crankshaft connecting rod ), the volume change of the working gas acting forces into mechanical work.

The efficiency of internal combustion engines is highly dependent on the operating point due to the implementation of the chemically bound energy of the fuel heat release into mechanical work. In the optimum condition, the effective efficiency of marine engines can using the exhaust heat for up to 55 %, respectively ( Emma Mærsk class). Taking into account also the use of cooling water heat ( cogeneration ) and even CO2 emissions, such as for greenhouses, the benefits may be more than 90 % in relation to the effort. The efficiency of car engines in the cold run, or even at idle may be below 10%. A general statement is not possible and is closely related to the application ( efficiency = benefit / cost and fuel consumption).

Optimization of combustion engines

To control the fresh air, control of incoming and outgoing gases by valves or rotary valve is synchronized with the work cycles in the standard engines.

By ( originating from the aircraft ) turbocharger fresh air is fed with increased density and thereby increases the efficiency of the engines. In gasoline engines, the fuel supply is improved by injectors. They are electrically controlled and so integrated into modern electronic control of motors. Similarly, comes in diesel engines, the pump -nozzle system, and common- rail fuel injection to improve performance for use.

Means fuel cut-off and start-stop system achieves a fuel consumption optimization.

Compression-ignition ( diesel)

Can the combustion of a fuel without aids - only by the high compression of the air - fuel mixture - take place, it is a self-igniting, He ignited by pressure filling of the combustion chamber. There have been improvements in the modification of the combustion chambers, pistons and nozzles, and the conveying pump and for the increase of the injection pressure, the better mixing of fuel associated with the air and the systematic variation of the fuel metering. In the wake of these developments, the vortex flow chamber has been replaced by direct injection.

The glow of the diesel engine or multi-fuel engine are only an aid to cold start; alternatively highly flammable Start fuels can be fed at startup. There were no significant changes, but only modifications to the glow plugs.

An external igniter (petrol engine )

The compression of the engine is not so high as that of the compression-ignition engine, it is required spark plugs have been developed by Bosch to noncorrosive to ignite the reaction mixture. Improvements, there has been the choice of material of the spark plugs (platinum ) and by the utter takeover by electronic engine sensors and first mechanical and electronic control soon.

Development and Future

In vehicle is this motor group, the most commonly used, especially as gasoline and diesel engine. It makes up the bulk of the vehicle drives for car and truck, diesel, tank, etc., small aircraft and motor gliders, flight - and motor boats, yachts, lawn mowers and many other applications.

The engine is mechanically a development of the steam engine and has to be further optimized from today's perspective, for decades to come, the best conditions in consumption, in terms of efficiency and in the use of materials of the engine. The optimization is done in part by other fuels or working fluid such as hydrogen, in which almost pure water vapor is formed, as well as by combinatorial energy utilization in hybrid drive concepts.

Gas turbines

Turbines, combustion gases are such that the steam turbine of the " thermal fluid energy machine ", but in the group of internal combustion engines. As flow machines they are both.

Each gas turbine has a turbine compressor, a combustor and a turbine, which is mechanically coupled to the most about the same shaft with the compressor. The compressed air from the compressor is burned in the combustion chamber at temperatures up to 1500 ° C with the injected fuel. The outflowing at high velocity combustion gases drive the turbine ( in rocket deleted them). The turbine deprives them at least those flow energy that is needed to drive the compressor. The rest is available as usable energy available - either mechanical energy for driving a shaft ( power station, helicopter ) or as recoil.

Efficiency and Applications

The hotter the gases, the higher the efficiency of gas turbines. Here, and in the ideal shape of the turbine blades are great possibilities of engine construction. A key factor here is the thermal capacity of blades and casing.

Aerospace applications are given by the very good power to mass ratio of the gas turbines, such as an engine for helicopters or turboprop aircraft. The kinetic energy of the combustion gases but can also be used for recoil aircraft propulsion. With so-called jet jets are used, the principle of which substantially corresponds to the gas turbine: The three components of the gas turbine is followed by a pure nozzle, through the exit of the exhaust gas stream. The turbine receives only as much energy (rotation speed ) as needed to drive the compressor.

Applications in shipping: It is therefore not a favorable ratio power - mass of than on low fuel consumption. Therefore, the more efficient diesel engine, which can be in contrast to the gas turbine operated with a favorable heavy oil, this displaced in the civilian sector. For military use it is sometimes used because of its greater smoothness. For air cushion vehicles, the gas turbine is often chosen.

Application in power plants (two types of gas turbines can be distinguished ):

  • Heavy design (Heavy Frame): the turbines have thought power of over 50 MW (up to several hundred MW) and for stationary continuous operation in large power plants.
  • Lightweight Design: aviation turbine derivatives or Aircraft Derivative have outputs of 100 kW to 40 MW and are structurally similar to the aircraft turbines. For use in industrial power plants these turbines are often part of a combined heat and power generation or a CCGT (gas and steam power plant). Conveniently, they are also powerful for emergency power generators, such as hospitals, because they only need a few minutes to complete startup.

In some turbines the pitch angle of the turbine blades can be changed; see also variable - turbine geometry loader.

Stirling engine

The Stirling engine converts heat energy into mechanical energy, must necessarily take place without the need for combustion. For the operation of a temperature difference must exist and be retained on the engine.

Rocket motors

Rocket motors typically produce from chemical energy via the detour of the heat energy mechanical energy. See also rocket, rocketry. Exceptions that operate purely physical, are:

  • Cold and hot water rockets,
  • Ion propulsion

Electric motor

The most frequently used motors are electric motors. Drives of different size and performance can be found in virtually all machinery equipment, machines and means of production - of miniaturized servo and stepper motors for household, office, air and car to industrial plants.

The development will find less used in the engine itself and in the optimization of the application, eg by power electronic control instead.

Electric motors are energy converters, which convert electric current into rotary or linear motion ( linear motor). Larger induction motors are often standardized ( DIN, Germany ), which unifies the production and the use of motors. European electric motor products are often subject to the CEE standard.

Electric motors are available for DC, AC and three-phase. You can find, especially in industrial plants and for electrical machines use. Also in toys or eg in PCs (fans, drives, hard disk) and in household appliances they are used.

Development trends are miniaturization and combining with control technology (sensors, power electronics ).

Recent developments relating to the large-scale application of superconductors is working intensively on. It is next to performance improvements in engine design also affect the transformer construction.

Nearly all electric motors can also be " reversed " work as generators, ie generate electrical energy in mechanical drive. Therefore can be recovered, for example, during braking or when elevators energy.

A special form of electric drives are the piezo motors.

Hydraulic motor

Hydraulic motors often operate on the reverse principle of a gear pump. To produce a rotary movement of the pressure and flow of a hydraulic fluid. They are comparatively small and can also produce high torque at standstill. They are used, inter alia, on excavators, tunnel boring machines and agriculture.

A derived version can be found in the flow transmissions, but is there not called that.

Pneumatic drives

Compressed air for the operation of turbines (eg, dental turbines (drill), centrifuges ) used or piston machines.

History

Hydropower and wind power have played a role in the history of the engine. Also, a water wheel, a motor, an energy converter: The energy supply of water at a higher position ( potential energy) of a pond or a river has been implemented by means of a water wheel in a rotary motion to drive millstones (water mill) or a sawmill.

Similarly, a wind turbine is an engine: the power of passing air is used to drive, for example, a millstone ( windmill ), a water pump or a generator.

Other historic drives worked with muscle power of animals or humans (see Göpel ). Even today, people or animals drifting in arid lands of pumping stations to pump water.

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