Edit filter log

'{{about|engines that use gaseous fuel|gasoline engines|Petrol engine|other uses|Internal combustion engine}} A '''gas engine''' means an engine running on gas, such as [[coal gas]], [[producer gas]] [[biogas]], landfill gas, or natural gas. In the [[United Kingdom|UK]], the term is unambiguous. In the [[United States|US]], due to the widespread use of "gas" as an abbreviation for [[gasoline]], such an engine might also be called a gaseous fuelled engine or a spark ignited engine. Generally the term gas engine refers to a heavy duty, slow revving industrial engine capable of running continuously at full output for periods approaching a high fraction of 8,760 hours per year, for many years, with indefinite lifetime, unlike say a gasoline automobile which is lightweight, high revving and typically runs for no more than 4,000 hours in its entire life. Typical power ranges from 10 kW to 4,000 kW. ==History== There were many experiments with gas engines in the [[19th century]] but the first practical engine was built by the Belgian engineer [[Étienne Lenoir]] in 1860 <ref>http://library.thinkquest.org/C006011/english/sites/gasmotoren.php3?v=2</ref>. The best known builder of gas engines in the [[UK]] was [[Crossley]], but there were several other firms based in the [[Manchester]] area as well. The [[Anson Engine Museum]] in [[Poynton]], near Manchester, [[England]], has a collection of engines that includes several working gas engines, as well as the first UK-built [[Diesel engine]] by [[Mirrlees]]. British engines mentioned above were of the slow-speed type&mdash;less than 1000 rpm&mdash;and used pilot diesel injection for ignition. Modern gas engines are of the high speed type&mdash;1500 rpm&mdash;and use spark ignition. British manufactures did not invest in developing the technology and were superseded by more forward-thinking suppliers. ==Current manufacturers== Manufacturers of gas engines include [[GE_Energy|GE Jenbacher]], [[Caterpillar Inc.]], [[Perkins Engines]], [[MWM (Motoren Werke Mannheim AG)|MWM]], [[Cummins]] and [[Wärtsilä]] Waukesha, Guascor, Deutz, MTU, MAN. Output ranges from about 50 kW to 4MW.<ref name="GE Jenbacher J624">[http://www.ge-energy.com/prod_serv/products/recip_engines/en/j624_gs.htm GE Jenbacher J624], Retrieved 27.02/09</ref> Generally speaking, the modern high-speed gas engine is competitive with gas turbines up to about 5 MW depending on actual circumstances. Caterpillar and many other manufacturers are based on a diesel engine block and crankshaft. GE Jenbacher are the sole company whose engines are designed and dedicated to gas alone. ==Typical applications== Typical applications are [[baseload]] or high-hour generation schemes, including [[combined heat and power]], [[landfill]] gas, [[mining|mine]]s gas, [[oil well|well]]-head gas and [[biogas]] (where the waste heat from the engine may be used to warm the digesters) and landfill gas. For typical biogas engine installation parameters see <ref>[http://www.claverton-energy.com/38-hhv-caterpillar-bio-gas-engine-fitted-to-long-reach-sewage-works.html]caterpillar-bio-gas-engine-fitted-to-long-reach-sewage-works-thames water</ref>. For parameters of a large gas engine chp system, as fitted in a factory, see <ref name="claverton-energy.com">http://www.claverton-energy.com/first-energy-offer-excellent-condition-complete-gas-engined-chp-system-for-sale-and-installation.html</ref> Gas engines are rarely used for standby applications, which remain largely the province of diesel engines. One exception to this is the small (<150KW) emergency generator often installed by farms, museums, small businesses, and residences. Connected to either natural gas from the public utility or propane from on-site storage tanks, these generators can be arranged for automatic starting upon power failure. ==Use of methane or propane gases== Since [[natural gas]] ([[methane]]) has long been a clean, economical, and readily available fuel, many industrial engines are either designed or modified to use gas, as distinguished from [[gasoline]]. Although the carbon emission footprint does not differ meaningfully, their operation produces less complex-hydrocarbon pollution, and the engines have fewer internal problems. One example is the [[Liquefied petroleum gas]] ([[propane]]) engine used in vast numbers of [[forklift truck]]s. Regrettably, common usage of 'gas' to mean 'gasoline' requires the explicit identification of a natural gas engine. (There is also such a thing as 'natural gasoline', but this term is very rarely observed outside the refining industry.) ==Technical details== A gas engine differs from a petrol engine in the way the fuel and air are mixed. A petrol engine uses a [[carburetor]] or [[fuel injection]] but a gas engine often uses a venturi system to introduce gas into the air flow. Early gas engines used a three-valve system, with separate inlet valves for air and gas. The weak point of a gas engine compared to a [[diesel engine]] is the exhaust valves, since the gas engine exhaust gases are much hotter for a given output, and this limits the power output. Thus a diesel engine from a given manufacturer will usually have a higher maximum output than the same engine block size in the gas engine version. The diesel engine will generally have three different ratings - Standby, Prime, and Continuous, (UK, 1 hour rating, 12 hour rating and continuous rating) whereas the gas engine will generally only have a Continuous rating, which will be less than the Diesel Continuous rating ==Energy Balance== ===Electrical efficiency=== Gas engine linked to generators that run on natural gas are typically between 35-45% electrically efficient. Fuel energy arises at the output shaft, the remainder appears as waste heat.<ref name="claverton-energy.com"/> Higher efficiencies are achieved in larger engines than smaller engines. Gas engines running on [[biogas]] typically have a slightly lower efficiency (~1-2%) and [[syngas]] reduces the efficiency further still. GE Jenbacher's recent J624 engine is the world's first 24 cylinder gas engine with a high efficiency running on methane.<ref name="GE Jenbacher J624"/> ===Combined heat and power=== {{main|Cogeneration}} Engine reject heat can be used for building heating or heating a process. In an engine, roughly half the waste heat arises (from the engine jacket, oil cooler and after cooler circuits) as hot water which can be at up to 110^oC. The remainder arises as high temperature heat which can generate pressurised hot water or steam by the use of an exhaust gas [[heat exchanger]]. ==Two fuels== A gas engine can be designed to run on gas, or oil, or a mixture of the two. There are two different configurations. ===Dual fuel engine=== This can run on oil alone, or a mixture of gas and oil. It cannot run on gas alone because it has no spark ignition system. ===Alternative fuel engine=== This can run on oil or gas but not a mixture of the two. When running on oil, it uses compression ignition as in a [[diesel engine]]. When running on gas it uses [[spark ignition]]. The term "[[Bi-fuel vehicle|Bi-fuel]]" may be preferable to "Alternative fuel" because the latter term is, nowadays, often used to mean any non-petroleum fuel. gas-engines Illuminating gas Illuminating gas is also known as "town gas". It was used for lighting and heating purposes. As inflammable constituents, illuminating gas contains hydrogen, methane, but also carbon monoxide, which is poisonous. The engineers quickly realized that a more suitable fuel than gun powder must be found. About one hundred years after Huygen's experiments, people believed to have found it in illuminating gas. The young Frenchman Philippe Lebon d'Humbersin (1767 - 1804) was celebrated as its discoverer. In 1801, He announced a patent on a gas engine. Due to his early death, he could not, unfortunately, realize his project. During the next half century, many setbacks hindered a fast development of the engines. The engineers did not succeed in building a stable running piston engine with internal combustion. Partially interesting patents were announced by different engineers, but their execution failed too often. Samuel Brown, who built the first motor vehicle which was documented (1823), was an exception. He used a gas engine developed by himself. explosion engines In gas engines, fuel burns in a big explosion. In today's combustion engines, explosions do not occur by no means. Although the term "explosion engine" held itself still in the vernacular. An explosion of fuel in the cylinder leads to the notorious "knocking" or "pinking" of an engine. Eugenio Barsanti (1821-1864), an Italian scientist, developed in the early 50s of the 19th century his atmospheric engine. It used a "Voltaic (from Volta) pistol" as ignition mechanism. A spark skipping between two electrodes ignited the gas mixture. Eugenio Barsanti (1821-1864), an Italian scientist, developed in the early 50s of the 19th century his atmospheric engine. It used a "Voltaic (from Volta) pistol" as ignition mechanism. A spark skipping between two electrodes ignited the gas mixture. Only in 1860, the Belgian Jean Joseph Etienne Lenoir (1822-1900) had success with his engines, which operated with illuminating gas. He did not invent any new machine, but assembled many well-known sections and built in such a way a double working engine, which was sold very well in the small trade. The engine reached just the poor efficiency of 3%, though. atmospheric engine vs. double working engine atmospheric engine In an atmospheric engine, the actual work is not carried out by the explosion of gas and the following acceleration of the piston. When the piston arrives at its highest point, the air pressure (therefore "atmospheric") and the piston's dead weight drive it into the cylinder below, which contains after the cooling of the gas an almost complete vacuum. The work is transferred to a flywheel. See sketch Otto's atmospheric engine. double working engine The double working engine has a cylinder. On the way from one extreme to the middle of the cylinder, a fuel mixture gets sucked performing work on the piston after the ignition during the other half of the way. On the other side, the discharge of the burned gas takes place at the same time. Now the engine works in the opposite direction, using the same principle. Now, fresh gas flows in from the other side. See also sketch Lenoir-engine. Grafic: double working engine. source: Helmut Hütten, "Motoren", Motorbuchverlag Stuttgart, S.32 At Lenoirs time, Alphonse Beau de Rochas (1815-1893) discovered the favourable effect of a compression of the gas mixture. But he could not use this important discovery in the industry. The compression stroke led later to the development of the four-stroke engine by Nikolaus Otto. At the world exhibition of 1867 in Paris, Nikolaus August Otto's (1832-1891) and Eugen Langen's (1833-1895) success with the atmospheric engine began. The engine was working with illuminating gas, too, and achieved a better efficiency of about 30 percent than the Lenoir engines because of a better technology. During the following 10 years, Otto's atmospheric engine was sold about 5000 times and so it was the first combustion engine that was produced in big quantities. 1869, Otto and Langen founded the gas engine factory "Deutz". Many other engineers also became well-known there, e.g. Wilhelm Maybach or Gottlieb Daimler. In the animation beside, the mode of operation of an atmospheric engine can be observed. The explosion of illuminating gas, the following acceleration of the piston, the ejection of the cooled gases and then the working stroke. Work is only performed at the flywheel when the piston goes downward, moved by its own weight and the atmospheric pressure. Down in the combustion chamber the fresh gas is ignited by a small flame. After few years of production, the demand was already satisfied in the small trade. Attempts to replace illuminating gas for petroleum failed too. The burn was too dangerous; the enormous carburetor uneconomical. People already did not believe in a progress with that kind of engines any more, when Otto revolutionized the engine industry with his ingenious inventions. <gallery> <gallery> Image:Example.jpg|Caption1 Image:Example.jpg|Caption2 </gallery> </gallery> ==See also== * [[Autogas]] * [[Gas turbine]] * [[History of the internal combustion engine]] * [[List of natural gas vehicles]] * [[Tables of European biogas utilisation]] ==External links== * [http://www.simt.co.uk/collections/collections-2-4.html Crossley Gas Engine] * [http://engines.rustyiron.com Antique Stationary Engines] * [http://www.old-engine.com/ Old Engines] * [http://www.smokstak.com/articles/ Gas Engine Articles] * [http://www.gasenginemagazine.com Gas Engine Magazine] - An internal combustion historical magazine *[http://lngtrucks.westport.com/index.php LNG Truck] {{DEFAULTSORT:Gas Engine}} [[Category:Engines]] [[Category:Stationary engines]] [[Category:Alternative propulsion]] [[Category:Internal combustion piston engines]] [[de:Gasmotor]] [[nn:Gassmotor]] [[ru:Газовый двигатель]]'