A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as E10 and E85).
Most petrol engines use spark ignition, unlike diesel engines which typically use compression ignition. Another key difference to diesel engines is that petrol engines typically have a lower compression ratio.
Most petrol engines use either the four-stroke Otto cycle or the two-stroke cycle.Petrol engines have also been produced using the Miller cycle and Atkinson cycle.
Most petrol-powered piston engines are straight engines or V engines. However, flat engines, W engines and other layouts are sometimes used.
Wankel engines are classified by the number of rotors used.
Petrol engines are either air-cooled or water-cooled.
Petrol engines use spark ignition and high voltage current for the spark may be provided by a magneto or an ignition coil. In modern car engines the ignition timing is managed by an electronic Engine Control Unit.
The power output of small- and medium-sized petrol engines (along with equivalent engines using other fuels) is usually measured in kilowatts or horsepower.
Typically, petrol engines have a thermodynamic efficiency of about 20% (approximately half that of some diesel engines).
Applications of petrol engines include automobiles, motorcycles, aircraft, motorboats and small engines (such as lawn mowers, chainsaws and portable generators).
The first practical petrol engine was built in 1876 in Germany by Nicolaus August Otto, : p15 Siegfried Marcus in 1864 : p79 and George Brayton in 1876. : pp413–414although there had been earlier attempts by Étienne Lenoir in 1860,
The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values.
The Diesel cycle is a combustion process of a reciprocating internal combustion engine. In it, fuel is ignited by heat generated during the compression of air in the combustion chamber, into which fuel is then injected. This is in contrast to igniting the fuel-air mixture with a spark plug as in the Otto cycle (four-stroke/petrol) engine. Diesel engines are used in aircraft, automobiles, power generation, diesel–electric locomotives, and both surface ships and submarines.
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-called compression-ignition engine. This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine or a gas engine.
A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common features of all types. The main types are: the internal combustion engine, used extensively in motor vehicles; the steam engine, the mainstay of the Industrial Revolution; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either a spark-ignition (SI) engine, where the spark plug initiates the combustion; or a compression-ignition (CI) engine, where the air within the cylinder is compressed, thus heating it, so that the heated air ignites fuel that is injected then or earlier.
The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion.
Timeline of motor and engine technology
In engineering, the Miller cycle is a thermodynamic cycle used in a type of internal combustion engine. The Miller cycle was patented by Ralph Miller, an American engineer, U.S. Patent 2,817,322 dated Dec 24, 1957. The engine may be two- or four-stroke and may be run on diesel fuel, gases, or dual fuel.
A stratified charge engine describes a certain type of internal combustion engine, usually spark ignition (SI) engine that can be used in trucks, automobiles, portable and stationary equipment. The term "stratified charge" refers to the working fluids and fuel vapors entering the cylinder. Usually the fuel is injected into the cylinder or enters as a fuel rich vapor where a spark or other means are used to initiate ignition where the fuel rich zone interacts with the air to promote complete combustion. A stratified charge can allow for slightly higher compression ratios without "knock," and leaner air/fuel ratio than in conventional internal combustion engines.
A four-strokeengine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed:
The Atkinson-cycle engine is a type of internal combustion engine invented by James Atkinson in 1882. The Atkinson cycle is designed to provide efficiency at the expense of power density.
Lean-burn refers to the burning of fuel with an excess of air in an internal combustion engine. In lean-burn engines the air:fuel ratio may be as lean as 65:1. The air / fuel ratio needed to stoichiometrically combust gasoline, by contrast, is 14.64:1. The excess of air in a lean-burn engine emits far less hydrocarbons. High air–fuel ratios can also be used to reduce losses caused by other engine power management systems such as throttling losses.
Gasoline direct injection (GDI), also known as petrol direct injection (PDI), is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber. This is distinct from manifold fuel injection systems, which inject fuel into the intake manifold.
The Otto engine was a large stationary single-cylinder internal combustion four-stroke engine designed by the German Nicolaus Otto. It was a low-RPM machine, and only fired every other stroke due to the Otto cycle, also designed by Otto.
Homogeneous Charge Compression Ignition (HCCI) is a form of internal combustion in which well-mixed fuel and oxidizer are compressed to the point of auto-ignition. As in other forms of combustion, this exothermic reaction releases energy that can be transformed in an engine into work and heat.
A spark-ignition engine is an internal combustion engine, generally a petrol engine, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug. This is in contrast to compression-ignition engines, typically diesel engines, where the heat generated from compression together with the injection of fuel is enough to initiate the combustion process, without needing any external spark.
A model engine is a small internal combustion engine typically used to power a radio-controlled aircraft, radio-controlled car, radio-controlled boat, free flight, control line aircraft, or ground-running tether car model.
Various scientists and engineers contributed to the development of internal combustion engines. In 1791, the English inventor John Barber patented a gas turbine. In 1794 Thomas Mead patented a gas engine. Also in 1794 Robert Street patented an internal-combustion engine, which was also the first to use liquid fuel (petroleum) and built an engine around that time. In 1798, John Stevens designed the first American internal combustion engine. In 1807, French engineers Nicéphore and Claude Niépce ran a prototype internal combustion engine, using controlled dust explosions, the Pyréolophore. This engine powered a boat on the Saône river, France. The same year, the Swiss engineer François Isaac de Rivaz built and patented a hydrogen and oxygen powered internal-combustion engine. The fuel was stored in a balloon and the spark was electrically ignited by a hand-operated trigger. Fitted to a crude four-wheeled wagon, François Isaac de Rivaz first drove it 100 meters in 1813, thus making history as the first car-like vehicle known to have been powered by an internal-combustion engine. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially in the U.S.; one of his engines pumped water on the Croydon Canal from 1830 to 1836. He also demonstrated a boat using his engine on the Thames in 1827, and an engine-driven carriage in 1828. Father Eugenio Barsanti, an Italian engineer, together with Felice Matteucci of Florence invented the first real internal combustion engine in 1853. Their patent request was granted in London on June 12, 1854, and published in London's Morning Journal under the title "Specification of Eugene Barsanti and Felix Matteucci, Obtaining Motive Power by the Explosion of Gasses". In 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nicolaus Otto patented the first atmospheric gas engine. In 1872, American George Brayton invented the first commercial liquid-fueled internal combustion engine. In 1876, Nicolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-stroke cycle engine. In 1879, Karl Benz patented a reliable two-stroke gas engine. In 1892, Rudolf Diesel developed the first compressed charge, compression ignition engine. In 1926, Robert Goddard launched the first liquid-fueled rocket. In 1939, the Heinkel He 178 became the world's first jet aircraft. In 1954 German engineer Felix Wankel patented a "pistonless" engine using an eccentric rotary design.
Internal combustion engines come in a wide variety of types, but have certain family resemblances, and thus share many common types of components.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. This replaced the external combustion engine for applications where the weight or size of an engine was more important.
Partially premixed combustion (PPC), also known as PPCI or GDCI is a modern combustion process intended to be used in internal combustion engines of automobiles and other motorized vehicles in the future. Its high specific power, high fuel efficiency and low exhaust pollution have made it a promising technology. As a compression-ignition engine, the fuel mixture ignites due to the increase in temperature that occurs with compression rather than a spark from a spark plug. A PPC engine injects and premixes a charge during the compression stroke. This premixed charge is too lean to ignite during the compression stroke – the charge will ignite after the last fuel injection ends near TDC. The fuel efficiency and working principle of a PPC engine resemble those of Diesel engine, but the PPC engine can be run with a variety of fuels. Also, the partially premixed charge burns clean. Challenges with using gasoline in a PPC engine arise due to the low lubricity of gasoline and the low cetane value of gasoline. Use of fuel additives or gasoline-diesel or gasoline-biodiesel blends can mitigate the various problems with gasoline.