Internal combustion engine

An internal combustion engine by combustion is converted into mechanical work, an internal combustion engine, the chemical energy of a fuel. The combustion thereby takes place in the combustion chamber, in which a mixture of fuel and ambient air is ignited. The thermal expansion of the hot combustion gas is used to move a piston. Common examples of internal combustion engines are the gasoline engine and the diesel engine in automobiles.

Steam turbines, steam engines or Stirling engines are not counted as internal combustion engines. The necessary heat for its operation does not need to be generated by combustion. The continuous aggregates gas turbine and rocket engines are usually not to the internal combustion engines.

Basic principle of operation

All piston engines work with four process steps: Intake, compression, power, exhaust. Depending on the construction and operation of the engine, these operations are controlled differently. , Is important for the function that, by the combustion of a fuel-air mixture, the expansion takes place at a higher pressure than the compression. The possible efficiency depends on the temperature level from where the heat of combustion is supplied, and thus the compression ratio. Modern passenger car gasoline engines achieve the best operating point ( approximately in the middle of the rpm range and just below the full load curve ) effective efficiency of 36%. In diesel engines, this is 43 %.

Classification

In the history of engine design, many concepts have been devised and implemented that do not necessarily fit into the following grid, for example, gasoline engines with direct or multi-fuel engines ( such as diesel ), but with the spark plug. For the sake of readability waived this overview to special cases.

The types can be combined in a wide variety, such as small-volume engines with rotary piston and diaphragm control according to the Otto principle ( Wankel engine ), or high-volume two- stroke diesel engines with valve control ( marine diesel ).

After working procedures

According to the sequence of motions

  • Reciprocating engine ( typically used in combination with the connecting rod and crankshaft, sometimes articulated connecting rods or crankshaft loose cam engines)
  • Rotary piston engine (such as the Wankel engine or McMastermotor )
  • Free-piston engine ( piston linear movement )
  • Mederer engine ( longer dwell time of the piston at top dead center, quasi- constant-volume combustion )

After the mixture formation process

Optimal combustion can take place only when the fuel is fully vaporised and mixed with air. This mixture can form in the diesel engine only within, held in gasoline engines outside of the cylinder.

After the ignition

  • Ignition
  • Self-ignition
  • Controlled auto-ignition or homogeneous charge compression ignition ( HCCI )

The ignition is the characteristic of the gasoline engine. In this case, the ignition of the fuel / air mixture is initiated by a spark plug, optimally just before the top dead center.

The self-ignition is the feature of the diesel engine. In this pure air is first strongly compressed and heated by it. Diesel fuel is injected just before the top dead center ( OT), which is ignited by the high heat of itself.

The controlled auto-ignition is currently being developed for various internal combustion engines. The mixture formation to take place internally but early so that the mixture is well mixed to ignition ( homogeneous). This better emission values ​​are achieved.

After the firing process

With burning method and the combustion process in internal combustion engines, called the sequence with which is performed the combustion of fuel in the engine.

  • The layer charge ( FSI petrol engine)
  • The BPI combustion processes ( gasoline engine )
  • The jet -guided combustion system (petrol engine )

After the fill type

  • Naturally aspirated
  • Supercharged engine
  • Cycle engine

After the cooling process

  • Liquid cooled
  • Air-cooled
  • Oil -cooled
  • Combinations of Luft-/Ölkühlung ( SAME)
  • Nitrogen cooling

According to types and number of cylinders

Depending on the number of cylinders / petrol and diesel engines have been or four-stroke and two-stroke engines built as:

  • Single cylinder engine ( 1)
  • Series motor (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16)
  • U motor (4, 12, 16)
  • V-engine (2, 4, 6, 8, 10, 12, 16, 20, 24)
  • VR motor (5, 6, 8, 12, 16 )
  • W motor (3, 8, 12, 16, 18, 24 )
  • Y motor (3, 6, 12, 18, 24)
  • H- motor (16, 24, 40)
  • X-motor (16, 24)
  • Piston engine (2, 4, 6, 8, 12)
  • Motor star (3, 5, 7, 9, 11)
  • Row radial engine ( 6x2 = 12, 4x3 = 12, 6x4 = 24, 4x5 = 20, 2x6 = 12, 4x6 = 24, 6x6 = 36, 3x7 = 21, 4x7 = 28, 6x7 = 42, 8x7 = 56, 4x9 = 36 )
  • Multiple radial engine ( 2x7 = 14, 2x9 = 18, 4x7 = 28 )
  • Rotary motor (1, 2, 4, 5, 7, 9, 14)
  • Opposed piston engine (only two-stroke eg Deltic engine ( three opposed-piston engines each other in a triangular shape ) )
  • Swash plate motor ( only four-stroke )

The bold designs and cylinder numbers today are built in motor vehicles.

Four-stroke radial engines typically have always an odd number of cylinders in the star. However, if several stars are arranged one behind the other, they can total a straight cylinders have (row radial engines and multiple radial engines ). Radial engines with an even number of cylinders in the star are only several rows before (eg Daimler- Benz DB 604, Rolls -Royce Vulture and Allison X -4520 ( with six four - stars and a total of 24 cylinders - represents 90 ° / 90 ° / 90 ° - X24 ) Junkers Jumo 222 and Dobrynin WD -4K (with four six- stars ( Hexagon ) and also total 24 cylinders ) or Curtiss H -1640 Chieftain ( with two six - stars ( Hexagon ) and twelve cylinders ) ).

In motor sport, are separated, despite the higher imbalance, including V- engines built with odd numbers of cylinders (three or five).

For slow- speed diesel engines, there are some cases up to 14 cylinders, layout, and V- engines with 20 or 24 cylinders.

Unusual types

The Wankel engine is a type which is named after Felix Wankel. In the Wankel engine, two kinematic forms are possible: First, the rotary engine in which an arched - triangular flask in an oval disk-shaped housing with a slightly oscillating motion to the eccentric shaft ( practically corresponds to the crankshaft while reciprocating engine ) " wobbles ". Secondly, the rotary piston engine in which both rotate the arched - triangular rotor and the oval - shaped disc- envelope figure ( trochoid ) about their priorities.

The Stelzer engine, named after its inventor Frank Stelzer, is a two-stroke free-piston engine. The Stelzer engine only, the piston is moved during the entire work process. Open Its different piston diameter and include various openings in the cabinet and simultaneously control the gas exchange.

In the first half of the 20th century a number of exotic structures was designed, but not to exceed the prototype stage. Due to advancement of materials research are possible solutions for problems of old constructions.

Fuels

  • Motor gasoline (see also: petrol, octane number)
  • Diesel fuel
  • JP -8 ( jet fuel, used in military diesel engines)
  • JP -5 ( jet fuel, used in military diesel engines)
  • Biodiesel ( vegetable oil after esterification )
  • Vegetable oil
  • Fatty acid methyl esters ( as an additive to diesel )
  • Petroleum gas ( LPG)
  • Methane (natural gas (CNG ), biogas, wood gas)
  • Methanol ( MeOH; CH3OH )
  • Ethanol (EtOH; C2H5OH )
  • Hythane (CH4 and H2)
  • Ethanol (pure or blended )
  • Tar oil, heavy oil (for larger stationary and marine engines )
  • Coal dust
  • Hydrogen
  • Generator gas
  • Blast furnace gas
  • Wood gas
  • Silane ( in development)
  • Nitromethane (usually only as a fuel additive )

Major engine manufacturers

Scuderi Engine Engine knocking Naturally aspirated engine U engine VR6 engine W engine H engine Axial engine Rolls-Royce Vulture Pistonless rotary engine JP-8 Autogas Carbolineum Split-single
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