Internal combustion engine

ICEV redirects here. For the form of water ice, see IceV. For the high speed train, see ICE V.An internal combustion engine (ICE) is an engine

Diagram of a cylinder as found in 4 stroke gasoline engines.:C crankshaft.E exhaust camshaft.I inlet camshaft.P piston.R connecting rod.S spark plug.V valves. red: exhaust, blue: intake.W cooling water jacket.gray structure engine block.

where the combustion of a fuel occurs with an oxidizer(usually air) in a combustion chamber that is an integralpart of the working uid ow circuit. In an internal com-bustion engine the expansion of the high-temperature andhigh-pressure gases produced by combustion apply directforce to some component of the engine. The force is ap-plied typically to pistons, turbine blades, or a nozzle. Thisforce moves the component over a distance, transformingchemical energy into useful mechanical energy. The rstcommercially successful internal combustion engine wascreated by tienne Lenoir around 1859.[1]

The term internal combustion engine usually refers to anengine in which combustion is intermittent, such as themore familiar four-stroke and two-stroke piston engines,along with variants, such as the six-stroke piston engine

and the Wankel rotary engine. A second class of internalcombustion engines use continuous combustion: gas tur-bines, jet engines and most rocket engines, each of whichare internal combustion engines on the same principle aspreviously described.[1][2] Firearms are also a form of in-ternal combustion engine.[2]

Internal combustion engines are quite dierent fromexternal combustion engines, such as steam or Stirlingengines, in which the energy is delivered to a workinguid not consisting of, mixed with, or contaminated bycombustion products. Working uids can be air, hot wa-ter, pressurized water or even liquid sodium, heated in aboiler. ICEs are usually powered by energy-dense fuelssuch as gasoline or diesel, liquids derived from fossil fu-els. While there are many stationary applications, mostICEs are used in mobile applications and are the domi-nant power supply for cars, aircraft, and boats.Typically an ICE is fed with fossil fuels like natural gasor petroleum products such as gasoline, diesel fuel orfuel oil. Theres a growing usage of renewable fuels likebiodiesel for compression ignition engines and bioethanolfor spark ignition engines. Hydrogen is sometimes used,and can be made from either fossil fuels or renewable en-ergy.

1 HistoryMain article: History of the internal combustion engine

2 EtymologyAt one time, the word engine (from Latin, via Old French,ingenium, ability) meant any piece of machinery asense that persists in expressions such as siege engine. Amotor (from Latinmotor, mover) is any machine thatproduces mechanical power. Traditionally, electric mo-tors are not referred to as Engines"; however, combus-tion engines are often referred to as motors. (An electricengine refers to a locomotive operated by electricity.)

3 ApplicationsReciprocating piston engines are by far the most commonpower source for land vehicles including automobiles,

1

2 5 RECIPROCATING ENGINES

Reciprocating engine as found inside a car

motorcycles, locomotives and ships. Wankel engines arefound on some automobiles and motorcycles.Where very high power-to-weight ratios are required,internal combustion engines appear in the form ofcombustion turbines. Powered aircraft typically use anICE which may be a reciprocating engine. Airplanescan also use jet engines and helicopters can also employturboshafts; both of these are types of turbines. In addi-tion to providing propulsion, airliners employ a separateICE as an auxiliary power unit.

Big Diesel generator used for backup power

Combined cycle power plant

ICEs also have a role in large scale electric power gener-ation where they're found in the form of combustion tur-bines in combined cycle power plants with typical elec-trical output in the range of 100 MW to 1 GW. The hightemperature exhaust is used to boil and superheat water torun a steam turbine. Thus, more energy is extracted fromthe fuel that could be extracted by the combustion tur-bine alone. In combined cycle power plants ecienciesin the range of 50 % to 60 % are typical. In a smallerscale Diesel generators are used for backup power andfor providing electrical power to areas not connected toan electric grid.Two-stroke engines are widely used in snowmobiles,lawnmowers, string trimmers, chain saws, jet skis,mopeds, outboard motors, and many motorcycles.Two stroke gasoline small engines are a common powersource for chainsaws, leafblowers and lawnmowers.

4 Engine congurationsInternal combustion engines can be classied by theirconguration.Common layouts of engines are:Reciprocating:

Two-stroke engine Four-stroke engine (Otto cycle) Six-stroke engine Diesel engine Atkinson cycle Miller cycle Axial

Rotary:

Wankel engine

Continuous combustion:

Gas turbine Jet engine (including turbojet, turbofan, ramjet,rocket, etc.)

5 Reciprocating enginesSee also: Diesel engine and Gasoline engine

5.1 Structure 3

Bare cylinder block of a V8 engine

Piston, piston ring, gudgeon pin and connecting rod

5.1 Structure

The base of a reciprocating internal combustion engineis the engine block which is typically made of cast ironor aluminium. The engine block contains the cylinders.In engines with more than 1 cylinder they're usually ar-ranged either in 1 row (straight engine) or 2 rows (boxerengine or V engine); 3 rows are occasionally used (W en-gine) in contemporary engines, and other engine cong-urations are possible and have been used. Single cylinderengines are common for motorcycles and in small enginesof machinery. Water cooled engines contain passages inthe engine block where cooling uid circulate (the waterjacket). Some small engines are air cooled, and instead ofhaving a water jacket the cylinder block has ns protrud-ing away from it to cool by directly transferring heat tothe air. The cylinder walls are usually nished by honingto obtain a cross hatch which is better able to retain theoil. A too rough surface would quickly harm the engineby excessive wear on the piston.The pistons are short cylindrical parts which seal oneend of the cylinder from the high pressure of the com-pressed air and combustion products and slide continu-ously within it while the engine is in operation. The topwall of the piston is termed its crown and is typically ator concave. Some two stroke engines use pistons with adeector head. Pistons are open at the bottom and hollowexcept for an integral reinforcement structure (the pistonweb). When an engine is working the gas pressure in thecombustion chamber exerts a force on the piston crownwhich is transferred through its web to a gudgeon pin.Each piston has rings tted around its circumference thatmostly prevent the gases from leaking into the crankcaseor the oil into the combustion chamber. A ventilationsystem drives the small amount of gas that escape pastthe pistons during normal operation (the blow-by gases)out of the crankcase so that it does not accumulate con-taminating the oil and creating corrosion. In two strokegasoline engines the crankcase is part of the airfuel pathand due to the continuous ow of it they do not need aseparate crankcase ventilation system.The cylinder head is attached to the engine block by nu-merous bolts or studs. It has several functions. The cylin-der head seals the cylinders on the side opposite to thepistons; it contains short ducts (the ports) for intake andexhaust and the associated intake valves that open to letthe cylinder be lled with fresh air and exhaust valves thatopen to allow the combustion gases to escape. However,2-stroke crankcase scavenged engines connect the gasports directly to the cylinder wall without poppet valves;the piston controls their opening and occlusion instead.The cylinder head also holds the spark plug in the case ofspark ignition engines and the injector for engines that usedirect injection. All CI engines use fuel injection, usuallydirect injection but some engines instead use indirect in-jection. SI engines can use a carburetor or fuel injectionas port injection or direct injection. Most SI engines have

4 5 RECIPROCATING ENGINES

Valve train above a Diesel engine cylinder head. This engine usesrocker arms but no pushrods.

a single spark plug per cylinder but some have 2. A headgasket prevents the gas from leaking between the cylin-der head and the engine block. The opening and clos-ing of the valves is controlled by one or several camshaftsand springsor in some enginesa desmodromic mech-anism that uses no springs. The camshaft may press di-rectly the stem of the valve or may act upon a rocker arm,again, either directly or through a pushrod.

Engine block seen from below. The cylinders, oil spay nozzle andhalf of the main bearings are clearly visible.

The crankcase is sealed at the bottom with a sump thatcollects the falling oil during normal operation to be cy-cled again. The cavity created between the cylinder blockand the sump houses a crankshaft that converts the recip-rocating motion of the pistons to rotational motion. Thecrankshaft is held in place relative to the engine blockby main bearings, which allow it to rotate. Bulkheadsin the crankcase form a half of every main bearing; theother half is a detachable cap. In some cases a singlemain bearing deck is used rather than several smaller caps.A connecting rod is connected to oset sections of thecrankshaft (the crankpins) in one end and to the piston inthe other end through the gudgeon pin and thus transfersthe force and translates the reciprocating motion of thepistons to the circular motion of the crankshaft. The end

of the connecting rod attached to the gudgeon pin is calledits small end, and the other end, where it is connected tothe crankshaft, the big end. The big end has a detachablehalf to allow assembly around the crankshaft. It is kepttogether to the connecting rod by removable bolts.The cylinder head has attached an intake manifold andan exhaust manifold to the corresponding ports. The in-take manifold connects to the air lter directly, or to acarburetor when one is present, which is then connectedto the air lter. It distributes the air incoming from thesedevices to the individual cylinders. The exhaust manifoldis the rst component in the exhaust system. It collects theexhaust gases from the cylinders and drives it to the fol-lowing component in the path. The exhaust system of anICE may also include a catalytic converter and muer.The nal section in the path of the exhaust gases is thetailpipe.

5.2 4-stroke engines

Main article: 4-stroke engineThe top dead center (TDC) of a piston is the posi-

Diagram showing the operation of a 4 stroke SI engine. Labels:1 Induction2 Compression3 Power4 Exhaust

tion where it is nearest to the valves; bottom dead center(BDC) is the opposite position where it is furtherest fromthem. A stroke is the movement of a piston from TDCto BDC or vice versa together with the associated pro-

5.3 2-stroke engines 5

cess. While an engine is in operation the crankshaft ro-tates continuously at a nearly constant speed. In a 4-strokeICE each piston experiments 2 strokes per crankshaft rev-olution in the following order. Starting the description atTDC, these are:[3][4]

1. Intake, induction or suction: The intake valves areopen as a result of the cam lobe pressing down on thevalve stem. The piston moves downward increasingthe volume of the combustion chamber and allowingair to enter in the case of a CI engine or an air fuelmix in the case of SI engines that do not use directinjection. The air or air-fuel mixture is called thecharge in any case.

2. Compression: In this stroke, both valves are closedand the piston moves upward reducing the combus-tion chamber volume which reaches its minimumwhen the piston is at TDC. The piston performswork on the charge as it is being compressed; as aresult its pressure, temperature and density increase;an approximation to this behavior is provided by theideal gas law. Just before the piston reaches TDC,ignition begins. In the case of a SI engine, the sparkplug receives a high voltage pulse that generates thespark which gives it its name and ignites the charge.In the case of a CI engine the fuel injector quicklyinjects fuel into the combustion chamber as a spray;the fuel ignites due to the high temperature.

3. Power orworking stroke: The pressure of the com-bustion gases pushes the piston downward exertingmore work than it was made to compress the charge.Complementary to the compression stroke, the com-bustion gases expand and as a result their tempera-ture, pressure and density decreases. When the pis-ton is near to BDC the exhaust valve opens. Thecombustion gases expand irreversibly due to the left-over pressurein excess of back pressure, the gaugepressure on the exhaust port, this is called theblowdown.

4. Exhaust: The exhaust valve remains open whilethe piston moves upward expelling the combustiongases. For naturally aspirated engines a small partof the combustion gases may remain in the cylin-der during normal operation because the piston doesnot close the combustion chamber completely; thesegases dissolve in the next charge. At the end ofthis stroke, the exhaust valve closes, the intake valveopens, and the sequence repeats in the next cycle.The intake valve may open before the exhaust valvecloses to allow better scavenging.

5.3 2-stroke engines

Main article: 2-stroke engine

The dening characteristic of this kind of engine is thateach piston completes a cycle every crankshaft revolution.The 4 process of intake, compression, power and exhausttake place in only 2 strokes so that it is not possible todedicate a stroke exclusively for each of them. Starting atTDC the cycle consist of:

1. Power: While the piston is descending the com-bustion gases perform work on itas in a 4-strokeengine. The same thermodynamical considera-tions about the expansion apply.

2. Scavenging: Around 75 of crankshaft rotation be-fore BDC the exhaust valve or port opens, and blow-down occurs. Shortly thereafter the intake valve ortransfer port opens. The incoming charge displacesthe remaining combustion gases to the exhaust sys-tem and a part of the charge may enter the exhaustsystem as well. The piston reaches BDC and re-verses direction. After the piston has traveled ashort distance upwards into the cylinder the exhaustvalve or port closes; shortly the intake valve or trans-fer port closes as well.

3. Compression: With both intake and exhaust closedthe piston continues moving upwards compressingthe charge and performing a work on it. As in thecase of a 4-stroke engine, ignition starts just beforethe piston reaches TDC and the same considerationon the thermodynamics of the compression on thecharge.

While a 4-stroke engine uses the piston as a positive dis-placement pump to accomplish scavenging taking 2 ofthe 4 strokes, a 2-stroke engine uses the last part of thepower stroke and the rst part of the compression strokefor combined intake and exhaust. The work required todisplace the charge and exhaust gases comes from eitherthe crankcase or a separate blower. For scavenging, ex-pulsion of burned gas and entry of fresh mix, two mainapproaches are described: 'Loop scavenging', and 'Uni-ow scavenging', SAE news published in the 2010s that'Loop Scavenging' is better under any circumstance than'Uniow Scavenging'.

5.3.1 Crankcase scavenged

Some SI engines are crankcase scavenged and do not usepoppet valves. Instead the crankcase and the part of thecylinder below the piston is used as a pump. The intakeport is connected to the crankcase through a reed valve ora rotary disk valve driven by the engine. For each cylin-der a transfer port connects in one end to the crankcaseand in the other end to the cylinder wall. The exhaustport is connected directly to the cylinder wall. The trans-fer and exhaust port are opened and closed by the pis-ton. The reed valve opens when the crankcase pressureis slightly below intake pressure, to let it be lled with a

6 5 RECIPROCATING ENGINES

Diagram of a crankcase scavenged 2-stroke engine in operation

new charge; this happens when the piston is moving up-wards. When the piston is moving downwards the pres-sure in the crankcase increases and the reed valve closespromptly, then the charge in the crankcase is compressed.When the piston is moving upwards, it uncovers the ex-haust port and the transfer port and the higher pressureof the charge in the crankcase makes it enter the cylin-der through the transfer port, blowing the exhaust gases.Lubrication is accomplished by adding 2-stroke oil to thefuel in small ratios. Petroil refers to the mix of gasolinewith the aforesaid oil. This kind of 2-stroke engines hasa lower eciency than comparable 4-strokes engines andrelease a more polluting exhaust gases for the followingconditions:

They use a total-loss lubrication system: all the lubri-cating oil is eventually burned along with the fuel.

There are conicting requirements for scavenging:On one side, enough fresh charge needs to be intro-duced in each cycle to displace almost all the com-bustion gases but introducing too much of it meansthat a part of it gets in the exhaust.

They must use the transfer port(s) as a carefully

designed and placed nozzle so that a gas currentis created in a way that it sweeps the whole cylin-der before reaching the exhaust port so as to expelthe combustion gases, but minimize the amount ofcharge exhausted. 4-stroke engines have the bene-t of forcibly expelling almost all of the combustiongases because during exhaust the combustion cham-ber is reduced to its minimum volume. In crankcasescavenged 2-stroke engines, exhaust and intake areperformed mostly simultaneously and with the com-bustion chamber at its maximum volume.

The main advantage of 2-stroke engines of this type ismechanical simplicity and a higher power-to-weight ratiothan their 4-stroke counterparts. Despite having twice asmany power strokes per cycle, less than twice the powerof a comparable 4-stroke engine is attainable in practice.

5.3.2 Blower scavenged

Diagram of uniow scavenging

5.4 Ignition 7

Using a separate blower avoids many of the shortcom-ings of crankcase scavenging, at the expense of increasedcomplexity which means a higher cost and an increase inmaintenance requirement. An engine of this type usesports or valves for intake and valves for exhaust, exceptopposed piston engines, which may also use ports for ex-haust. The blower is usually of the Roots-type but othertypes have been used too. This design is commonplace inCI engines, and has been occasionally used in SI engines.CI engines that use a blower typically use uniow scav-enging. In this design the cylinder wall contains severalintake ports placed uniformly spaced along the circumfer-ence just above the position that the piston crown reacheswhen at BDC. An exhaust valve or several like that of 4-stroke engines is used. The nal part of the intake man-ifold is an air sleeve which feeds the intake ports. Theintake ports are placed at an horizontal angle to the cylin-der wall (I.e: they are in plane of the piston crown) togive a swirl to the incoming charge to improve combus-tion. The largest reciprocating IC are low speed CI en-gines of this type; they are used for marine propulsion(see marine diesel engine) or electric power generationand achieve the highest thermal eciencies among inter-nal combustion engines of any kind. SomeDiesel-electriclocomotive engines operate on the 2-stroke cycle. Themost powerful of them have a brake power of around4.5 MW or 6,000 HP. The EMD SD90MAC class of lo-comotives use a 2-stroke engine. The comparable classGEAC6000CWwhose primemover has almost the samebrake power uses a 4-stroke engine.An example of this type of engine is the Wrtsil-Sulzer RTA96-C turbocharged 2-stroke Diesel, used inlarge container ships. It is the most ecient and pow-erful internal combustion engine in the world with athermal eciency over 50 %.[5][6][7][8] For comparison,the most ecient small four-stroke engines are around 43% thermally-ecient (SAE 900648); size is an advantagefor eciency due to the increase in the ratio of volumeto surface area.See the external links for a in-cylinder combustion videoin a 2-stroke, optically accessible motorcycle engine.

5.4 Ignition

Internal combustion engines require ignition of the mix-ture, either by spark ignition (SI) or compression ignition(CI). Before the invention of reliable electrical methods,hot tube and ame methods were used. Experimental en-gines with laser ignition have been built.[9]

5.4.1 Gasoline Ignition Process

Gasoline engine ignition systems generally rely on a com-bination of alternator or generator and leadacid batteryfor electrical power. The battery supplies electrical power

for cranking, and supplies electrical power when the en-gine is o. The battery also supplies electrical power dur-ing rare run conditions where the alternator cannot main-tain more than 13.8 volts (for a common 12V automotiveelectrical system). As alternator voltage falls below 13.8volts, the lead-acid storage battery increasingly picks upelectrical load. During virtually all running conditions,including normal idle conditions, the alternator suppliesprimary electrical power.Some systems disable alternator eld (rotor) power dur-ing wide open throttle conditions. Disabling the eld re-duces alternator pulley mechanical loading to nearly zero,maximizing crankshaft power. In this case the batterysupplies all primary electrical power.Gasoline engines take in a mixture of air and gasolineand compress it to not more than 12.8 bar (1.28 MPa).When mixture is compressed, as the piston approachesthe cylinder head and maximum stroke, a spark plug ig-nites the mixture.The necessary high voltage, typically 10,000 volts to over30,000 volts, is supplied by an induction coil or trans-former. The induction coil is a y-back system, usinginterruption of electrical primary system current throughsome type of synchronized interrupter. The interruptercan be either contact points or a power transistor. Someignition systems are capacitive discharge types. CD igni-tions use step-up transformers. The step-up transformeruses energy stored in a capacitance to generate electricspark. With either system, a mechanical or electrical con-trol system provides a carefully timed high-voltage to theproper cylinder. This spark, via the spark plug, ignites theair-fuel mixture in the engines cylinders.While gasoline internal combustion engines are mucheasier to start in cold weather than diesel engines, theycan still have cold weather starting problems under ex-treme conditions. For years the solution was to park thecar in heated areas. In some parts of the world the oilwas actually drained and heated over night and returnedto the engine for cold starts. In the early 1950s the gaso-line Gasier unit was developed, where, on cold weatherstarts, raw gasoline was diverted to the unit where partof the fuel was burned causing the other part to becomea hot vapor sent directly to the intake valve manifold.This unit was quite popular until electric engine blockheaters became standard on gasoline engines sold in coldclimates.[10]

5.4.2 Diesel Ignition Process

Diesel engines and HCCI (Homogeneous charge com-pression ignition) engines, rely solely on heat and pressurecreated by the engine in its compression process for igni-tion. The compression level that occurs is usually twiceor more than a gasoline engine. Diesel engines take in aironly, and shortly before peak compression, spray a smallquantity of diesel fuel into the cylinder via a fuel injec-

8 5 RECIPROCATING ENGINES

tor that allows the fuel to instantly ignite. HCCI typeengines take in both air and fuel, but continue to relyon an unaided auto-combustion process, due to higherpressures and heat. This is also why diesel and HCCIengines are more susceptible to cold-starting issues, al-though they run just as well in cold weather once started.Light duty diesel engines with indirect injection in auto-mobiles and light trucks employ glowplugs that pre-heatthe combustion chamber just before starting to reduce no-start conditions in cold weather. Most diesels also have abattery and charging system; nevertheless, this system issecondary and is added by manufacturers as a luxury forthe ease of starting, turning fuel on and o (which canalso be done via a switch or mechanical apparatus), andfor running auxiliary electrical components and acces-sories. Most new engines rely on electrical and electronicengine control units (ECU) that also adjust the combus-tion process to increase eciency and reduce emissions.

5.5 Lubrication

Diagram of an engine using pressurized lubrication

Surfaces in contact and relative motion to other surfacesrequire lubrication to reduce wear, noise and increase ef-ciency by reducing the power wasting in overcomingfriction, or to make themechanismwork at all. An enginerequires lubrication in at least:

Between pistons and cylinders Small bearings Big end bearings Main bearings Valve gear (The following elements may not bepresent):

Tappets

Rocker arms Pushrods Timing chain or gears. Toothed belts do notrequire lubrication.

In 2-stroke crankcase scavenged engines, the interior ofthe crankcase, and therefore the crankshaft, connectingrod and bottom of the pistons are sprayed by the 2-strokeoil in the air-fuel-oil mixture which is then burned alongwith the fuel. The valve train may be contained in a com-partment ooded with lubricant so that no oil pump isrequired.In a splash lubrication system no oil pump is used. In-stead the crankshaft dips into the oil in the sump and dueto its high speed, it splashes the crankshaft, connectingrods and bottom of the pistons. The connecting rod bigend caps may have an attached scoop to enhance this ef-fect. The valve train may also be sealed in a ooded com-partment, or open to the crankshaft in a way that it re-ceives splashed oil and allows it to drain back to the sump.Splash lubrication is common for small 4-stroke engines.In a forced (also called pressurized) lubrication system,lubrication is accomplished in a closed loop which carriesmotor oil to the surfaces serviced by the system and thenreturns the oil to a reservoir. The auxiliary equipment ofan engine is typically not serviced by this loop; for in-stance, an alternator may use ball bearings sealed with itslubricant. The reservoir for the oil is usually the sump,and when this is the case, it is called a wet sump system.When there is a dierent oil reservoir the crankcase stillcatches it, but it is continuously drained by a dedicatedpump; this is called a dry sump system.On its bottom, the sump contains an oil intake covered bya mesh lter which is connected to an oil pump then to anoil lter outside the crankcase, from there it is divertedto the crankshaft main bearings and valve train. Thecrankcase contains at least one oil gallery (a conduit insidea crankcase wall) to which oil is introduced from the oillter. The main bearings contain a groove through all orhalf its circumference; the oil enters to these grooves fromchannels connected to the oil gallery. The crankshaft hasdrillings which take oil from these grooves and deliver itto the big end bearings. All big end bearings are lubri-cated this way. A single main bearing may provide oil for0, 1 or 2 big end bearings. A similar system may be usedto lubricate the piston, its gudgeon pin and the small endof its connecting rod; in this system, the connecting rodbig end has a groove around the crankshaft and a drillingconnected to the groove which distributes oil from thereto the bottom of the piston and from then to the cylinder.Other systems are also used to lubricate the cylinder andpiston. Every crankshaft big end may have a nozzle tothrow an oil jet to the cylinder and bottom of the pis-ton. That nozzle is in movement relative to the cylinderit lubricates, but always pointed towards it or the corre-sponding piston. Instead, the nozzle can also be placed

5.7 Diesel cycle 9

xed in the crankshaft and pointing upwards.Typically a forced lubrication systems have a lubricantow higher than what is required to lubricate satisfacto-rily, in order to assist with cooling. Specically, the lubri-cant system helps to move heat from the hot engine partsto the cooling liquid (in water cooled engines) or ns (inair cooled engines) which then transfer it to the environ-ment. The lubricant must be designed to be chemicallystable andmaintain suitable viscosities within the temper-ature range it encounters in the engine.

5.6 Cylinder conguration

Common cylinder congurations include the straight orinline conguration, the more compact V conguration,and the wider but smoother at or boxer conguration.Aircraft engines can also adopt a radial conguration,which allows more eective cooling. More unusual con-gurations such as the H, U, X, and W have also beenused.Multiple cylinder engines have their valve train andcrankshaft congured so that pistons are at dierent partsof their cycle. It is desirable to have the pistons cy-cles uniformly spaced (this is called even ring) espe-cially in forced induction engines; this reduces torquepulsations[11] and makes inline engines with more than 3cylinders statically balanced in its primary forces. How-ever, some engine congurations require odd ring toachieve better balance than what is possible with evenring. For instance, a 4 stroke I2 engine has better bal-ance when the angle between the crankpins is 180 be-cause the pistons move in opposite directions and inertialforces partially cancel, but this gives an odd ring patternwhere one cylinder res 180 of crankshaft rotation afterthe other, then no cylinder res for 540. With an evenring pattern the pistons would move in unison and theassociated forces would add.Multiple crankshaft congurations do not necessarilyneed a cylinder head at all because they can instead havea piston at each end of the cylinder called an opposedpiston design. Because fuel inlets and outlets are posi-tioned at opposed ends of the cylinder, one can achieveuniow scavenging, which, as in the four-stroke engine isecient over a wide range of engine speeds. Thermal ef-ciency is improved because of a lack of cylinder heads.This design was used in the Junkers Jumo 205 diesel air-craft engine, using two crankshafts at either end of a sin-gle bank of cylinders, and most remarkably in the NapierDeltic diesel engines. These used three crankshafts toserve three banks of double-ended cylinders arranged inan equilateral triangle with the crankshafts at the corners.It was also used in single-bank locomotive engines, and isstill used in marine propulsion engines and marine auxil-iary generators.

5.7 Diesel cycleMain article: Diesel cycleMost truck and automotive diesel engines use a cycle

p

VV2

p4p1

0 V1V3

1

2 3

4

p2

p: pressureV: specic volumeQin

Qout

Wout

Win

isentropic

isentropic

P-v Diagram for the Ideal Diesel cycle. The cycle follows thenumbers 14 in clockwise direction.

reminiscent of a four-stroke cycle, but with a compres-sion heating ignition system, rather than needing a sep-arate ignition system. This variation is called the dieselcycle. In the diesel cycle, diesel fuel is injected directlyinto the cylinder so that combustion occurs at constantpressure, as the piston moves.Otto cycle: Otto cycle is the typical cycle for most of thecars internal combustion engines, that work using gaso-line as a fuel. Otto cycle is exactly the same one that wasdescribed for the four-stroke engine. It consists of thesame four major steps: Intake, compression, ignition andexhaust.PV diagram for Otto cycle On the PV-diagram, 12: In-take: suction stroke 23: Isentropic Compression stroke34: Heat addition stroke 45: Exhaust stroke (Isen-tropic expansion) 52: Heat rejection The distance be-tween points 12 is the stroke of the engine. By dividingV2/V1, we get: r, where r is called the compression ratioof the engine.

5.8 Five-stroke engineIn 1879, Nikolaus Otto manufactured and sold double ex-pansion engine (the double and triple expansion princi-ples had ample usage in steam engines), with two smallcylinders at both sides of a low-pressure larger cylinder,where a second expansion of exhaust stroke gas tookplace; the owner returned it, alleging poor performance.In 1906, the concept was incorporated in a car builtby EHV (Eisenhuth Horseless Vehicle Company) CT,USA. (ref: 'The Romance of Engines, Takashi Suzuki,

10 6 COMBUSTION TURBINES

Ph.D., pags: 87-94, SAE, 1997), and in the 21st cen-tury, ILMOR designed and successfully tested a 5-strokedouble expansion internal combustion engine, with highpower output and low SFC (Specic Fuel Consumption).

5.9 Six-stroke engine

The six-stroke engine was invented in 1883. Fourkinds of six-stroke use a regular piston in a regularcylinder (Grin six-stroke, Bajulaz six-stroke, Velozetasix-stroke and Crower six stroke), ring every threecrankshaft revolutions. The systems capture the wastedheat of the four-stroke Otto cycle with an injection of airor water.The Beare Head and piston charger engines operate asopposed-piston engines, two pistons in a single cylinder,ring every two revolutions rather more like a regularfour-stroke.

5.10 Other cycles

The very rst internal combustion engines did not com-press the mixture. The rst part of the piston downstrokedrew in a fuel-air mixture, then the inlet valve closed and,in the remainder of the down-stroke, the fuel-air mix-ture red. The exhaust valve opened for the piston up-stroke. These attempts at imitating the principle of asteam engine were very inecient. There are a numberof variations of these cycles, most notably the Atkinsonand Miller cycles. The diesel cycle is somewhat dierent.Split-cycle engines separate the four strokes of intake,compression, combustion and exhaust into two separatebut paired cylinders. The rst cylinder is used for intakeand compression. The compressed air is then transferredthrough a crossover passage from the compression cylin-der into the second cylinder, where combustion and ex-haust occur. A split-cycle engine is really an air compres-sor on one side with a combustion chamber on the other.Previous split-cycle engines have had two majorproblemspoor breathing (volumetric eciency) andlow thermal eciency. However, new designs are beingintroduced that seek to address these problems.The Scuderi Engine addresses the breathing problemby reducing the clearance between the piston and thecylinder head through various turbo charging techniques.The Scuderi design requires the use of outwardly open-ing valves that enable the piston to move very close tothe cylinder head without the interference of the valves.Scuderi addresses the low thermal eciency via ringATDC.Firing ATDC can be accomplished by using high-pressure air in the transfer passage to create sonic owand high turbulence in the power cylinder.

6 Combustion turbines

6.1 Gas turbines

Main article: gas turbine

A gas turbine is called a gas turbine because it compressesa gas, usually air. There are three stages to a turbine: 1)air is drawn through a compressor where the temperaturerises due to compression, 2) fuel is added in the com-buster, and 3) hot air is exhausted through turbines bladeswhich rotate a shaft connected to the compressor.A gas turbine is a rotary machine similar in principle to asteam turbine and it consists of three main components:a compressor, a combustion chamber, and a turbine. Theair, after being compressed in the compressor, is heatedby burning fuel in it. About of the heated air, combinedwith the products of combustion, expands in a turbine,producing work output that drives the compressor. Therest (about ) is available as useful work output.

6.2 Jet engine

Main article: Jet engine

The jet engine takes a large volume of hot gas from acombustion process (typically a gas turbine, but rocketforms of jet propulsion often use solid or liquid propel-lants, and ramjet forms also lack the gas turbine) andfeeds it through a nozzle that accelerates the jet to highspeed. As the jet accelerates through the nozzle, this cre-ates thrust and in turn does useful work.

6.3 Brayton cycle

Main article: Brayton cycleA gas turbine is a rotary machine somewhat similar in

Fuel

Fresh Air Exhaust gasses

Combustion

Work out

Compressor Turbine

P

v

q in

q out

s = const.

s = const.

1

2 3

41

2 3

4

P-v Diagram

T

s

q in

q outp =

const

.

p =

cons

t.

1

2

3

4

T-s Diagram

Brayton cycle

principle to a steam turbine and it consists of three maincomponents: a compressor, a combustion chamber, and aturbine. The air is compressed by the compressor where atemperature rise occurs, further heated by combustion ofinjected fuel which heats and expands the air, this energyis tapped by the turbine and exhausted, which powers thecompressor and provides thrust.

11

Gas turbine cycle engines employ a continuous com-bustion system where compression, combustion, and ex-pansion occur simultaneously at dierent places in theenginegiving continuous power. Notably, the combus-tion takes place at constant pressure, rather than with theOtto cycle, constant volume.

7 Wankel engines

The Wankel cycle. The shaft turns three times for each rotationof the rotor around the lobe and once for each orbital revolutionaround the eccentric shaft.

Main article: Wankel engine

The Wankel engine (rotary engine) does not have pistonstrokes. It operates with the same separation of phasesas the four-stroke engine with the phases taking place inseparate locations in the engine. In thermodynamic termsit follows the Otto engine cycle, so may be thought of asa four-phase engine. While it is true that three powerstrokes typically occur per rotor revolution, due to the3:1 revolution ratio of the rotor to the eccentric shaft,only one power stroke per shaft revolution actually oc-curs. The drive (eccentric) shaft rotates once during ev-ery power stroke instead of twice (crankshaft), as in theOtto cycle, giving it a greater power-to-weight ratio thanpiston engines. This type of engine wasmost notably usedin the Mazda RX-8, the earlier RX-7, and other models.

8 Forced inductionMain article: Forced induction

Forced induction is the process of delivering compressedair to the intake of an internal combustion engine. Aforced induction engine uses a gas compressor to increasethe pressure, temperature and density of the air. An en-gine without forced induction is considered a naturallyaspirated engine.Forced induction is used in the automotive and aviationindustry to increase engine power and eciency. It par-ticularly helps aviation engines, as they need to operate athigh altitude.Forced induction is achieved by a supercharger, where thecompressor is directly powered from the engine shaft or,in the turbocharger, from a turbine powered by the engineexhaust.

9 Fuels and oxidizersAll internal combustion engines depend on combustionof a chemical fuel, typically with oxygen from the air(though it is possible to inject nitrous oxide to do more ofthe same thing and gain a power boost). The combustionprocess typically results in the production of a great quan-tity of heat, as well as the production of steam and carbondioxide and other chemicals at very high temperature; thetemperature reached is determined by the chemical makeup of the fuel and oxidisers (see stoichiometry), as wellas by the compression and other factors.

9.1 Fuels

The most common modern fuels are made up ofhydrocarbons and are derived mostly from fossil fuels(petroleum). Fossil fuels include diesel fuel, gasolineand petroleum gas, and the rarer use of propane. Ex-cept for the fuel delivery components, most internal com-bustion engines that are designed for gasoline use canrun on natural gas or liqueed petroleum gases with-out major modications. Large diesels can run with airmixed with gases and a pilot diesel fuel ignition injec-tion. Liquid and gaseous biofuels, such as ethanol andbiodiesel (a form of diesel fuel that is produced fromcrops that yield triglycerides such as soybean oil), can alsobe used. Engines with appropriate modications can alsorun on hydrogen gas, wood gas, or charcoal gas, as well asfrom so-called producer gas made from other convenientbiomass. Experiments have also been conducted usingpowdered solid fuels, such as the magnesium injectioncycle.Presently, fuels used include:

12 9 FUELS AND OXIDIZERS

Petroleum: Petroleum spirit (North American term:gasoline, British term: petrol)

Petroleum diesel. Autogas (liquied petroleum gas). Compressed natural gas. Jet fuel (aviation fuel) Residual fuel

Coal: Gasoline can be made from carbon (coal) us-ing the Fischer-Tropsch process

Diesel fuel can be made from carbon using theFischer-Tropsch process

Biofuels and vegoils: Peanut oil and other vegoils. Biofuels:

Biobutanol (replaces gasoline). Biodiesel (replaces petrodiesel). Dimethyl Ether (replaces petrodiesel). Bioethanol and Biomethanol (wood alco-hol) and other biofuels (see Flexible-fuelvehicle).

Biogas Hydrogen (mainly spacecraft rocket engines)

Even uidized metal powders and explosives have seensome use. Engines that use gases for fuel are called gasengines and those that use liquid hydrocarbons are calledoil engines; however, gasoline engines are also often col-loquially referred to as, gas engines (petrol enginesoutside North America).The main limitations on fuels are that it must be easilytransportable through the fuel system to the combustionchamber, and that the fuel releases sucient energy inthe form of heat upon combustion to make practical useof the engine.Diesel engines are generally heavier, noisier, and morepowerful at lower speeds than gasoline engines. Theyare also more fuel-ecient in most circumstances and areused in heavy road vehicles, some automobiles (increas-ingly so for their increased fuel eciency over gasolineengines), ships, railway locomotives, and light aircraft.Gasoline engines are used in most other road vehicles in-cluding most cars, motorcycles, and mopeds. Note thatin Europe, sophisticated diesel-engined cars have takenover about 45 % of the market since the 1990s. Thereare also engines that run on hydrogen, methanol, ethanol,liqueed petroleum gas (LPG), biodiesel, paran andtractor vaporizing oil (TVO).

9.1.1 Hydrogen

Main article: Hydrogen internal combustion enginevehicle

Hydrogen could eventually replace conventional fossil fu-els in traditional internal combustion engines. Alterna-tively fuel cell technologymay come to deliver its promiseand the use of the internal combustion engines could evenbe phased out.Although there are multiple ways of producing free hy-drogen, those methods require converting combustiblemolecules into hydrogen or consuming electric energy.Unless that electricity is produced from a renewablesourceand is not required for other purposes hydro-gen does not solve any energy crisis. In many situationsthe disadvantage of hydrogen, relative to carbon fuels,is its storage. Liquid hydrogen has extremely low den-sity (14 times lower than water) and requires extensiveinsulationwhilst gaseous hydrogen requires heavy tank-age. Even when liqueed, hydrogen has a higher specicenergy but the volumetric energetic storage is still roughlyve times lower than gasoline. However, the energy den-sity of hydrogen is considerably higher than that of elec-tric batteries, making it a serious contender as an energycarrier to replace fossil fuels. The 'Hydrogen on Demand'process (see direct borohydride fuel cell) creates hydro-gen as needed, but has other issues, such as the high priceof the sodium borohydride that is the raw material.

9.2 Oxidizers

Since air is plentiful at the surface of the earth, the oxi-dizer is typically atmospheric oxygen, which has the ad-vantage of not being stored within the vehicle. This in-creases the power-to-weight and power-to-volume ratios.Other materials are used for special purposes, often to in-crease power output or to allow operation under water orin space.

Compressed air has been commonly used intorpedoes.

Compressed oxygen, as well as some compressedair, was used in the Japanese Type 93 torpedo.Some submarines carry pure oxygen. Rockets veryoften use liquid oxygen.

Nitromethane is added to some racing andmodel fu-els to increase power and control combustion.

Nitrous oxide has been usedwith extra gasolinein tactical aircraft, and in specially equipped cars toallow short bursts of added power from engines thatotherwise run on gasoline and air. It is also used inthe Burt Rutan rocket spacecraft.

13

One-cylinder gasoline engine, c. 1910

Hydrogen peroxide power was under developmentfor German World War II submarines. It may havebeen used in some non-nuclear submarines, and wasused on some rocket engines (notably the Black Ar-row and the Me-163 rocket plane).

Other chemicals such as chlorine or uorine havebeen used experimentally, but have not been foundpractical.

10 Cooling

Main article: Internal combustion engine cooling

Cooling is required to remove excessive heatover heat-ing can cause engine failure, usually from wear, crackingor warping. Two most common forms of engine coolingare air-cooled and water cooled. Most modern automo-tive engines and larger engines are water cooled, whilemost power tool engines and other small engines are aircooled. Some engines (air or water cooled) also have anoil cooler. In some engines, especially for turbine en-gine blade cooling and liquid rocket engine cooling, fuelis used as a coolant, simultaneously preheating the fuel,before injecting it into a combustion chamber.

11 StartingMain article: Starter motor

An internal combustion engine is not usually self-startingso an auxiliary machine is required to start it. Many dif-ferent systems have been used in the past but modern en-gines are usually started by an electric motor in the smalland medium sizes or by compressed air in the large sizes.

12 Measures of engine perfor-mance

Engine types vary greatly in a number of dierent ways:

energy eciency fuel/propellant consumption (brake specic fuelconsumption for shaft engines, thrust specic fuelconsumption for jet engines)

power-to-weight ratio thrust to weight ratio Torque curves (for shaft engines) thrust lapse (jetengines)

Compression ratio for piston engines, overall pres-sure ratio for jet engines and gas turbines

12.1 Energy eciencyOnce ignited and burnt, the combustion productshotgaseshave more available thermal energy than theoriginal compressed fuel-air mixture (which had higherchemical energy). The available energy is manifested ashigh temperature and pressure that can be translated intowork by the engine. In a reciprocating engine, the high-pressure gases inside the cylinders drive the engines pis-tons.Once the available energy has been removed, the remain-ing hot gases are vented (often by opening a valve or ex-posing the exhaust outlet) and this allows the piston toreturn to its previous position (top dead center, or TDC).The piston can then proceed to the next phase of its cycle,which varies between engines. Any heat that is not trans-lated into work is normally considered a waste productand is removed from the engine either by an air or liquidcooling system.Internal combustion engines are primarily heat engines,and as such their theoretical eciency can be calculatedby idealized thermodynamic cycles. The eciency of atheoretical cycle cannot exceed that of the Carnot cycle,whose eciency is determined by the dierence between

14 13 AIR AND NOISE POLLUTION

the lower and upper operating temperatures of the en-gine. The upper operating temperature of a terrestrialengine is limited by the thermal stability of the materialsused to construct it. All metals and alloys eventually meltor decompose, and there is signicant researching intoceramic materials that can be made with greater thermalstability and desirable structural properties. Higher ther-mal stability allows for greater temperature dierence be-tween the lower and upper operating temperatures, hencegreater thermodynamic eciency.The thermodynamic limits assume that the engine is op-erating under ideal conditions: a frictionless world, idealgases, perfect insulators, and operation for innite time.Real world applications introduce complexities that re-duce eciency. For example, a real engine runs best at aspecic load, termed its power band. The engine in a carcruising on a highway is usually operating signicantlybelow its ideal load, because it is designed for the higherloads required for rapid acceleration. In addition, factorssuch as wind resistance reduce overall system eciency.Engine fuel economy is measured in miles per gallon orin liters per 100 kilometres. The volume of hydrocarbonassumes a standard energy content.Most steel engines have a thermodynamic limit of 37 %.Even when aided with turbochargers and stock eciencyaids, most engines retain an average eciency of about18 %20 %.[12] Rocket engine eciencies are much bet-ter, up to 70 %, because they operate at very high tem-peratures and pressures and can have very high expan-sion ratios.[13] Electric motors are better still, at around8590 % eciency or more, but they rely on an externalpower source (often another heat engine at a power plantsubject to similar thermodynamic eciency limits).There are many inventions aimed at increasing the e-ciency of IC engines. In general, practical engines are al-ways compromised by trade-os between dierent prop-erties such as eciency, weight, power, heat, response,exhaust emissions, or noise. Sometimes economy alsoplays a role in not only the cost of manufacturing the en-gine itself, but also manufacturing and distributing thefuel. Increasing the engines eciency brings better fueleconomy but only if the fuel cost per energy content isthe same.

12.2 Measures of fuel eciency and pro-pellant eciency

For stationary and shaft engines including propeller en-gines, fuel consumption is measured by calculating thebrake specic fuel consumption, which measures themass ow rate of fuel consumption divided by the powerproduced.For internal combustion engines in the form of jet en-gines, the power output varies drastically with airspeedand a less variable measure is used: thrust specic fuelconsumption (TSFC), which is the mass of propellant

needed to generate impulses that is measured in eitherpound force-hour or the grams of propellant neededto generate an impulse that measures one kilonewton-second.For rockets, TSFC can be used, but typically other equiv-alent measures are traditionally used, such as specic im-pulse and eective exhaust velocity.

13 Air and noise pollution

13.1 Air pollution

Internal combustion engines such as reciprocating inter-nal combustion engines produce air pollution emissions,due to incomplete combustion of carbonaceous fuel. Themain derivatives of the process are carbon dioxide CO2, water and some soot also called particulate mat-ter (PM). The eects of inhaling particulate matter havebeen studied in humans and animals and include asthma,lung cancer, cardiovascular issues, and premature death.There are, however, some additional products of the com-bustion process that include nitrogen oxides and sulfurand some uncombusted hydrocarbons, depending on theoperating conditions and the fuel-air ratio.Not all of the fuel is completely consumed by the com-bustion process; a small amount of fuel is present aftercombustion, and some of it reacts to form oxygenates,such as formaldehyde or acetaldehyde, or hydrocarbonsnot originally present in the input fuel mixture. Incom-plete combustion usually results from insucient oxygento achieve the perfect stoichiometric ratio. The ame isquenched by the relatively cool cylinder walls, leavingbehind unreacted fuel that is expelled with the exhaust.When running at lower speeds, quenching is commonlyobserved in diesel (compression ignition) engines that runon natural gas. Quenching reduces eciency and in-creases knocking, sometimes causing the engine to stall.Incomplete combustion also leads to the production ofcarbon monoxide (CO). Further chemicals released arebenzene and 1,3-butadiene that are also hazardous air pol-lutants.Increasing the amount of air in the engine reduces emis-sions of incomplete combustion products, but also pro-motes reaction between oxygen and nitrogen in the airto produce nitrogen oxides (NOx). NOx is hazardous toboth plant and animal health, and leads to the productionof ozone (O3). Ozone is not emitted directly; rather, itis a secondary air pollutant, produced in the atmosphereby the reaction of NO and volatile organic compoundsin the presence of sunlight. Ground-level ozone is harm-ful to human health and the environment. Though thesame chemical substance, ground-level ozone should notbe confused with stratospheric ozone, or the ozone layer,which protects the earth from harmful ultraviolet rays.Carbon fuels contain sulfur and impurities that eventually

15

produce sulfur monoxides (SO) and sulfur dioxide (SO2)in the exhaust, which promotes acid rain.In the United States, nitrogen oxides, PM, carbonmonox-ide, sulphur dioxide, and ozone, are regulated as criteriaair pollutants under the Clean Air Act to levels wherehuman health and welfare are protected. Other pollu-tants, such as benzene and 1,3-butadiene, are regulatedas hazardous air pollutants whose emissions must be low-ered as much as possible depending on technological andpractical considerations.

13.1.1 Non-road engines

Main article: Non-road engine Emission standards

The emission standards used by many countries have spe-cial requirements for non-road engines which are used byequipment and vehicles that are not operated on the pub-lic roadways. The standards are separated from the roadvehicles.[14]

13.2 Noise pollution

Signicant contributions to noise pollution are made byinternal combustion engines. Automobile and truck traf-c operating on highways and street systems producenoise, as do aircraft ights due to jet noise, particularlysupersonic-capable aircraft. Rocket engines create themost intense noise.

13.3 Idling

Main article: Idle reduction

Internal combustion engines continue to consume fueland emit pollutants when idling so it is desirable to keepperiods of idling to a minimum. Many bus companiesnow instruct drivers to switch o the engine when the busis waiting at a terminal.In the UK (but only in England), the Road Trac VehicleEmissions Fixed Penalty Regulations 2002 (Statutory In-strument 2002 No. 1808) [15] introduced the concept ofa "stationary idling oence". This means that a driver canbe ordered "by an authorised person ... upon productionof evidence of his authorisation, require him to stop therunning of the engine of that vehicle" and a "person whofails to comply ... shall be guilty of an oence and be li-able on summary conviction to a ne not exceeding level 3on the standard scale". Only a few local authorities haveimplemented the regulations, one of them being OxfordCity Council.[16]

14 See also

Adiabatic ame temperature

Air-fuel ratio

Bore

Component parts of internal combustion engines

Crude oil engine - a two-stroke engine

Deglazing (engine mechanics)

Diesel engine

Dieselisation

Direct injection

Dynamometer

Electric vehicle

Engine test stand - information about how to checkan internal combustion engine

External Combustion Engine

Fossil fuels

Gasoline direct injection

Gas turbine

Heat pump

Hybrid vehicle

Indirect injection

Jet engine

Magnesium injection cycle

Piston engine

Petrofuel

Reciprocating engine

Stroke

Turbocharger

Variable displacement

16 18 EXTERNAL LINKS

15 References[1] History of Technology: Internal Combustion engines.

Encyclopdia Britannica. Britannica.com. Retrieved2012-03-20.

[2] Pulkrabek, Willard W. (1997). Engineering Fundamen-tals of the Internal Combustion Engine. Prentice Hall. p.2. ISBN 9780135708545.

[3] Stone 1992, pp. 1-2.

[4] Nunney 2007, p. 5.

[5] Low Speed Engines, MAN Diesel.

[6] CFX aids design of worlds most ecient steam turbine(PDF). Retrieved 2010-08-28.

[7] New Benchmarks for Steam Turbine Eciency - PowerEngineering. Pepei.pennnet.com. 2010-08-24. Re-trieved 2010-08-28.

[8] Takaishi, Tatsuo; Numata, Akira; Nakano, Ryouji; Sak-aguchi, Katsuhiko (March 2008). Approach to High Ef-ciency Diesel and Gas Engines (PDF).Mitsubishi HeavyIndustries Technical Review 45 (1). Retrieved 2011-02-04.

[9] Laser sparks revolution in internal combustion engines.Physorg.com. 2011-04-20. Retrieved 2013-12-26.

[10] Gasier Aids Motor Starting Under Arctic Conditions.Popular Mechanics: 149. January 1953.

[11] Nunney 2007, p. 15.

[12] Improving IC Engine Eciency.Courses.washington.edu. Retrieved 2010-08-28.

[13] Rocket propulsion elements 7th edition-George Sutton,Oscar Biblarz pg 37-38

[14] 2013 Global Sourcing Guide. Diesel & Gas TurbinePublications. Retrieved 2013-12-26.

[15] The Road Trac (Vehicle Emissions) (Fixed Penalty)(England) Regulations 2002. 195.99.1.70. 2010-07-16.Retrieved 2010-08-28.

[16] CITY DEVELOPMENT - Fees & Charges 2010-11.Oxford City Council. November 2011. Retrieved 2011-02-04.

16 Bibliography Nunney, Malcom J. (2007). Light and Heavy Ve-hicle Technology (4th ed.). Elsevier Butterworth-Heinemann. ISBN 978-0-7506-8037-0.

Stone, Richard (1992). Introduction to InternalCombustion Engines (2nd ed.). Macmillan. ISBN0-333-55083-8.

Anyebe, E.A (2009). Combustion Engine and Oper-ations, Automobile Technology Handbook 2.

Singal, R. K. Internal Combustion Engines. NewDelhi, India: Kataria Books. ISBN 978-93-5014-214-1.

Ricardo, Harry (1931). The High-Speed InternalCombustion Engine.

Patents: ES 156621 ES 433850, Ubierna Laciana, Perfec-cionamientos en Motores de Explosion,con Cinco Tiem-Pos y Doble Expansion,published 1976-11-01

ES 230551, Ortuno Garcia Jose, Un NuevoMotor de Explosion, published 1957-03-01

ES 249247, Ortuno Garcia Jose, Motor deCarreras Distintas, published 1959-09-01

17 Further reading Singer, Charles Joseph; Raper, Richard (1978).Charles, Singer; et al, eds. A History of Technology:The Internal Combustion Engine. Clarendon Press.pp. 157176.

Setright, LJK (1975). Some unusual engines. Lon-don: The Institution of Mechanical Engineers.ISBN 0-85298-208-9.

Suzuki, Takashi (1997). The Romance of Engines.US: Society of Automotive Engineers. ISBN 1-56091-911-6.

Hardenberg, Horst O. (1999). The Middle Ages ofthe Internal Combustion Engine. US: Society of Au-tomotive Engineers.

Gunston, Bill (1999). Development of Piston AeroEngines. PSL. ISBN 978-1-85260-619-0.

18 External links Combustion video - in-cylinder combustion in anoptically accessible, 2-stroke engine

Animated Engines - explains a variety of types Intro to Car Engines - Cut-away images and a goodoverview of the internal combustion engine

Walter E. Lay Auto Lab - Research at The Univer-sity of Michigan

youtube - Animation of the components and built-upof a 4-cylinder engine

youtube - Animation of the internal moving parts ofa 4-cylinder engine

17

Next generation engine technologies retrieved May9, 2009

MITOverview - Present & Future Internal Combus-tion Engines: Performance, Eciency, Emissions,and Fuels

Engine Combustion Network - Open forum for in-ternational collaboration among experimental andcomputational researchers in engine combustion.

Automakers Show Interest in an Unusual EngineDesign

How Car Engines Work A le on unusual engines Aircraft Engine Historical Society -AEHS

18 19 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

19 Text and image sources, contributors, and licenses19.1 Text

Internal combustion engine Source: http://en.wikipedia.org/wiki/Internal%20combustion%20engine?oldid=645293294 Contributors:Magnus Manske, Brion VIBBER, Mav, Tarquin, Taw, Andre Engels, Aldie, Peterlin, Maury Markowitz, Heron, Topory, Edward, Patrick,RTC, Michael Hardy, Fred Bauder, Isomorphic, Liftarn, Gabbe, Wapcaplet, Ixfd64, GTBacchus, Delirium, Arpingstone, Ahoerstemeier,Mac, Jimfbleak, Jdforrester, Rlandmann, Andrewa, , Lupinoid, Glenn, GCarty, GRAHAMUK, Reddi, Blake (usurped), Ra-diojon, Tpbradbury, Maximus Rex, Greglocock, Taxman, LMB, Omegatron, Morven, Raul654, Proteus, Johnleemk, Pollinator, Owen,Lumos3, Twang, Paul W, Fredrik, RedWolf, Kowey, Romanm, Modulatum, Chancemill, Lowellian, Rhombus, Roscoe x, Hadal, Fuel-bottle, Vikingstad, Seano1, Alan Liefting, Cedars, Matt Gies, Giftlite, Unvjake, Christopher Parham, Wolfkeeper, BenFrantzDale, Lee JHaywood, Ferkelparade, RealGrouchy, Mark.murphy, Karn, Wwoods, Everyking, Michael Devore, Leonard G., Per Honor et Gloria, Qua-maretto, Mboverload, PlatinumX, Jackol, Bobblewik, Wmahan, Cbraga, Gzuckier, Antandrus, Beland, Salasks, Gunnar Larsson, PDH,Vina, Rdsmith4, Maximaximax, Tomandlu, Tomruen, PFHLai, Zfr, Ukexpat, Andy Christ, Sonett72, Trevor MacInnis, Arminius, Dmit-ryKo, Mike Rosoft, Brianjd, Mormegil, Reinthal, Hinrik, Discospinster, Rich Farmbrough, Avriette, Hydrox, Dpm64, Wrp103, Ardonik,Xezbeth, Edgarde, Closeapple, Loren36, Lauciusa, Aecis, Vanished user kjij32ro9j4tkse, Chairboy, Shanes, Sietse Snel, RoyBoy, Nrbelex,Femto, CDN99, Bobo192, Stesmo, Harald Hansen, Billymac00, Smalljim, Duk, Clarkbhm, Richi, Diceman, Kjkolb, Slambo, Towel401,DCEdwards1966, Cyrillic, Espoo, Ranveig, Danski14, Alansohn, Mick Knapton, Anthony Appleyard, Guaca, Interiot, Mr Adequate,Pen1234567, Johanfo, Fritzpoll, Mailer diablo, Yadyn, Hu, RPellessier, Yossiea, Stephan Leeds, Vcelloho, Andrewcool, SteinbDJ, GeneNygaard, Karpada, Tainter, HenryLi, Dennis Bratland, Zntrip, Nuno Tavares, Lincspoacher, Woohookitty, Mindmatrix, LOL, Fingers-of-Pyrex, Uncle G, Beefcalf, Pol098, WadeSimMiser, MGTom, Ampmouse, Tabletop, Kelisi, Lensovet, Bunthorne, BlaiseFEgan, Wayward,Waldorf, GraemeLeggett, Dysepsion, Wikimike, Graham87, Jcomp489, Zeromaru, BD2412, Newfoundlanddog, FreplySpang, James-Burns, Edison, Rjwilmsi, Pdelong, Jake Wartenberg, Mentality, Kazrak, Unfocused, Yamamoto Ichiro, Firebug, Motorhead, Titoxd,FlaBot, SchuminWeb, Mishuletz, Nihiltres, RexNL, BitterMan, Lmatt, Tysto, Tedder, SteveBaker, Compuneo, Scythe33, Butros, Chobot,DVdm, Shaggyjacobs, YurikBot, Wavelength, Eirik, RobotE, Sceptre, RussBot, Petiatil, Wambo, Rbelli, Anonymous editor, D0li0, Spuri-ousQ, Akamad, Grubber, Gaius Cornelius, Muchosucko, David R. 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19.2 Images 19

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19.3 Content license Creative Commons Attribution-Share Alike 3.0

History Etymology Applications Engine configurations Reciprocating engines Structure 4-stroke engines 2-stroke engines Crankcase scavenged Blower scavenged

Ignition Gasoline Ignition Process Diesel Ignition Process

Lubrication Cylinder configuration Diesel cycle Five-stroke engine Six-stroke engine Other cycles

Combustion turbines Gas turbines Jet engine Brayton cycle

Wankel engines Forced induction Fuels and oxidizers Fuels Hydrogen

Oxidizers

Cooling Starting Measures of engine performance Energy efficiency Measures of fuel efficiency and propellant efficiency

Air and noise pollution Air pollution Non-road engines

Noise pollution Idling

See also References BibliographyFurther reading External links Text and image sources, contributors, and licensesTextImagesContent license