Gas engine
The gas engine, a subset of the internal combustion engines, is a usually after the Otto cycle working internal combustion engine as fuel instead of liquid fuels ( gasoline, diesel, heavy fuel oil, etc.) natural gas, LPG, wood, biogas, landfill -, mine gas, blast furnace gas or hydrogen is used.
History
John Barber examined the first 1791, the operation of a motor which is operated by the force of an explosion of a gas. He received a patent on a device in which to be gassed in a retort with external firing wood, coal, oil, or other fuels, the product can be mixed in a second vessel with air and should be ignited when flowing. Through the emerging jet of fire then a paddle wheel should be operated.
In another patent Robert Street in 1794 describes a piston engine, whose cylinders are in tar oils or turpentine first gasified and then ignited by a flame that burns outside of the cylinder and can be set at an appropriate time in conjunction with the gas to be ignited.
The Frenchman Philippe Lebon (1767-1804) constructed a machine that should be operated by coal gas. Air and gas clumped means of two pumps separately in a template in which they unite and ignite. The combustion products should drive the piston of a double acting cylinder. For ignition Lebon recommends a electrical machine should be operated from the gas engine itself. Further improvements came from Samuel Brown in 1823 and Lemuel W. Wright, an American from New Hampshire ( 1833).
Really practical value gained the gas engine only with the invention of the native Luxembourger Étienne Lenoir (1822-1900), according to its letter dated January 24, 1860 patent of the Paris Industrial Marinoni first produced a few such machines. When, after a cleverly orchestrated campaign increased sales of these machines quickly, they founded a company for the construction of gas engines, the Société Lenoir. Although it turned out with the time that the maintenance costs of Lenoir engines were unreasonably high, the demand still remained at a high level, also because they run particularly noiseless.
1867 Nikolaus Otto was on the second Paris World Exhibition their newly constructed gas engine, which he improved step by step and the beginning of the 20th century had the largest circulation found.
Applications
Small and medium-sized gas engines in the power range from 20 to 1500 kW are now mostly used to generate electricity and heat production in plants with combined heat and power generation, such as cogeneration and energy recovery from lean gases as they arise during the fermentation of organic waste (Bio - and landfill gas ), of wood or gas.
Increasingly more widespread is the relatively simple conversion of "normal" passenger car gasoline engines for economic reasons ( currently about 50 % of the other fuel costs) and ecological designs.
Operation
The gas engine is constructed in contrast to the gas turbine and reciprocating engine or rotary engine. The ignition of the fuel -air mixture takes place at the plants on the basis of gasoline engines by spark ignition by spark plug in units based on diesel engines with compression ignition low -injected quantities Zündöls, generally diesel fuel. Wärtsilä operates at the high-pressure gas injection engine according to the diesel principle with a so -ignition of the high pressure directly injected into the combustion chamber of the fuel gas. The operating according to this method, motors achieve the highest mean pressures of all internal combustion engines. The MAN has now successfully tested the CIP process, in which a dual fuel (mostly diesel fuel ) is used. This is injected into a prechamber classic means of high-pressure injector and ignited with a mantle, which then also ignites the gas - air mixture.
An external mixture formation can be effected by the gas mixing unit, before or after a possible turbocharger internal mixture formation is possible by a separate gas inlet valves or needles.
Efficiency
Operation with high quality fuel gases such as methane (CH4), the main constituent of natural gas, are higher efficiencies possible, clean combustion and good CO2 balance are characterized. Stationary -powered plants for combined heat and power are subject to the Clean Air Act and thus significantly stricter limits than cars. The emission takes place at small engines that operate on the λ = 1 procedure by means of three-way catalysts, medium-speed systems in the lean method ( λ = 1.4-2.5 ) require oxidation or NOx storage catalysts or optionally urea or ammonia injection for NOx reduction.
Manufacturer
The main manufacturers for gas engines are GE Jenbacher in Jenbach / Austria, MWM in Mannheim / Germany and Caterpillar (USA).
Other manufacturers for gas engines are MAN, MTU Friedrichshafen, 2G, MTU Onsite Energy GmbH (formerly MDE Decentralized Energy Systems ), Ford, Perkins, Blohm Voss energy and environmental technology, Maschinenbau Halberstadt GmbH, Rolls- Royce Marine, Wärtsilä, Iveco Aifo, Kubota, Fast, agrogen and others.