Editing Vehicle (section)

== Locomotion ==
{{main|propulsion}}

Locomotion consists of a means that allows displacement with little opposition, a [[Power (physics)|power source]] to provide the required [[kinetic energy]] and a means to control the motion, such as a [[brake]] and [[steering]] system. By far, most vehicles use [[wheel]]s which employ the principle of [[rolling]] to enable displacement with very little [[rolling friction]].

=== Energy source ===
{{main|Energy storage#Storage methods}}
{{see also|Hybrid vehicle}}
[[File:Electric vehicle charging point - geograph.org.uk - 5804565.jpg|thumb|An [[electric car]] at a [[charging station]] in [[Crawfordjohn]], Scotland]]
It is essential that a vehicle have a source of energy to drive it. Energy can be extracted from external sources, as in the cases of a [[sailboat]], a [[solar-powered car]], or an electric [[streetcar]] that uses overhead lines. Energy can also be stored, provided it can be converted on demand and the storing medium's [[energy density]] and [[power density]] are sufficient to meet the vehicle's needs.

[[Human power]] is a simple source of energy that requires nothing more than humans. Despite the fact that humans cannot exceed {{convert|500|W|hp|abbr=on}} for meaningful amounts of time,<ref>{{cite web| title = Bicycle Power – How many Watts can you produce?| publisher = Mapawatt| url = http://blog.mapawatt.com/2009/07/19/bicycle-power-watts/| access-date = 23 July 2011}}</ref> the [[Cycling records|land speed record for human-powered vehicles]] (unpaced) is {{convert|133|km/h|mph|0|abbr=on}}, as of 2009 on a [[recumbent bicycle]].<ref name="Speed2009">{{cite web|url = http://www.wisil.recumbents.com/wisil/whpsc2009/results.htm|title = Battle Mountain World Human Powered Speed Challenge|access-date = 25 August 2011|last = WHPSC|date = September 2009|archive-url = https://web.archive.org/web/20130811101125/http://www.wisil.recumbents.com/wisil/whpsc2009/results.htm|archive-date = 11 August 2013|url-status = dead|df = dmy-all}}</ref>

The energy source used to power vehicles is [[fuel]]. External combustion engines can use almost anything that burns as fuel, whilst internal combustion engines and rocket engines are designed to burn a specific fuel, typically gasoline, [[diesel fuel|diesel]] or [[ethanol]]. Food is the fuel used to power non-motor vehicles such as cycles, rickshaws and other pedestrian-controlled vehicles.

Another common medium for storing energy is [[Battery (electricity)|batteries]], which have the advantages of being responsive, useful in a wide range of power levels, environmentally friendly, efficient, simple to install, and easy to maintain. Batteries also facilitate the use of electric motors, which have their own advantages. On the other hand, batteries have low energy densities, short service life, poor performance at extreme temperatures, long charging times, and difficulties with disposal (although they can usually be recycled). Like fuel, batteries store chemical energy and can cause burns and poisoning in event of an accident.<ref>{{cite web| title = Battery Safety| publisher = Electropaedia| url = http://www.mpoweruk.com/safety.htm| access-date = 23 July 2011| archive-date = 13 January 2012| archive-url = https://web.archive.org/web/20120113022101/http://www.mpoweruk.com/safety.htm| url-status = dead}}</ref> Batteries also lose effectiveness with time.<ref>{{cite web| title = The Lifecycle of an Electric Car Battery| publisher = [[HowStuffWorks]]| url = http://auto.howstuffworks.com/fuel-efficiency/vehicles/electric-car-battery4.htm| access-date = 23 July 2011| date = 2008-08-18}}</ref> The issue of charge time can be resolved by swapping discharged batteries with charged ones;<ref>{{cite web| title = Advantages and Disadvantages of EVs| publisher = [[HowStuffWorks]]| url = http://auto.howstuffworks.com/fuel-efficiency/vehicles/electric-car-battery3.htm| access-date = 23 July 2011| date = 2008-08-18}}</ref> however, this incurs additional hardware costs and may be impractical for larger batteries. Moreover, there must be standard batteries for [[battery swapping]] to work at a gas station. [[Fuel cells]] are similar to batteries in that they convert from chemical to electrical energy, but have their own advantages and disadvantages.

[[Third rail|Electrified rails]] and overhead cables are a common source of electrical energy on subways, railways, trams, and trolleybuses.
[[Solar energy]] is a more modern development, and several [[solar vehicles]] have been successfully built and tested, including [[NASA Pathfinder|Helios]], a solar-powered aircraft.

[[Nuclear power]] is a more exclusive form of energy storage, currently limited to large ships and submarines, mostly military. Nuclear energy can be released by a [[nuclear reactor]], [[nuclear battery]], or repeatedly detonating [[nuclear bombs]]. There have been two experiments with nuclear-powered aircraft, the [[Tupolev Tu-119]] and the [[Convair X-6]].

[[Deformation (mechanics)|Mechanical strain]] is another method of storing energy, whereby an elastic band or metal spring is deformed and releases energy as it is allowed to return to its ground state. Systems employing elastic materials suffer from [[hysteresis]], and metal springs are too dense to be useful in many cases.{{Clarify|date=July 2011}}

[[Flywheel energy storage|Flywheels]] store energy in a spinning mass. Because a light and fast rotor is energetically favorable, flywheels can pose a significant safety hazard. Moreover, flywheels leak energy fairly quickly and affect a vehicle's steering through the [[gyroscopic effect]]. They have been used experimentally in [[gyrobus]]es.

[[Wind energy]] is used by sailboats and [[land yacht]]s as the primary source of energy. It is very cheap and fairly easy to use, the main issues being dependence on weather and upwind performance. [[Balloon (aircraft)|Balloons]] also rely on the wind to move horizontally. Aircraft flying in the [[jet stream]] may get a boost from high altitude winds.

[[Compressed gas]] is currently an experimental method of storing energy. In this case, compressed gas is simply stored in a tank and released when necessary. Like elastics, they have [[hysteresis]] losses when gas heats up during compression.

[[Gravitational potential energy#Gravitational potential energy|Gravitational potential energy]] is a form of energy used in gliders, skis, [[bobsled]]s and numerous other vehicles that go down hill. [[Regenerative brake|Regenerative braking]] is an example of capturing [[kinetic energy]] where the brakes of a vehicle are augmented with a generator or other means of extracting energy.<ref name="regenerative">{{cite web| title = How Regenerative Braking Works| publisher = [[HowStuffWorks]]| url = http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking.htm| access-date = 23 July 2011| date = 2009-01-23}}</ref>

=== Motors and engines ===
{{main|Engine}}
[[File:Honda R18A Engine.JPG|thumb|A [[Honda R engine|Honda R18A engine]] in a [[Honda Civic (eighth generation)|2007]] [[Honda Civic]]]]
When needed, the energy is taken from the source and consumed by one or more motors or engines. Sometimes there is an intermediate medium, such as the batteries of a diesel submarine.<ref>{{cite web| title = How do the engines breathe in diesel submarines?| publisher = [[How Stuff Works]]| date = 24 July 2006| url = http://science.howstuffworks.com/transport/engines-equipment/question286.htm| access-date = 22 July 2011}}</ref>

Most motor vehicles have [[internal combustion engines]]. They are fairly cheap, easy to maintain, reliable, safe and small. Since these engines burn fuel, they have long ranges but pollute the environment. A related engine is the [[external combustion engine]]. An example of this is the steam engine. Aside from fuel, steam engines also need water, making them impractical for some purposes. Steam engines also need time to warm up, whereas IC engines can usually run right after being started, although this may not be recommended in cold conditions. Steam engines burning coal release [[sulfur]] into the air, causing harmful [[acid rain]].<ref>{{cite web| title = Coal and the environment| publisher = Kentucky Coal Education| url = http://www.coaleducation.org/lessons/twe/envi.pdf| access-date = 22 July 2011}}</ref>

While intermittent internal combustion engines were once the primary means of aircraft propulsion, they have been largely superseded by continuous internal combustion engines, such as [[gas turbine]]s. Turbine engines are light and, particularly when used on aircraft, efficient.{{Citation needed|date=July 2011}} On the other hand, they cost more and require careful maintenance. They can also be damaged by ingesting foreign objects, and they produce a hot exhaust. Trains using turbines are called [[gas turbine-electric locomotive]]s. Examples of surface vehicles using turbines are [[M1 Abrams]], [[MTT Turbine SUPERBIKE]] and the [[Millennium (ship)|Millennium]]. [[Pulse jet]] engines are similar in many ways to turbojets but have almost no moving parts. For this reason, they were very appealing to vehicle designers in the past; however, their noise, heat, and inefficiency have led to their abandonment. A historical example of the use of a pulse jet was the [[V-1 flying bomb]]. Pulse jets are still occasionally used in amateur experiments. With the advent of modern technology, the [[pulse detonation engine]] has become practical and was successfully tested on a [[Rutan VariEze]]. While the pulse detonation engine is much more efficient than the pulse jet and even turbine engines, it still suffers from extreme noise and vibration levels. [[Ramjets]] also have few moving parts, but they only work at high speed, so their use is restricted to [[tip jet]] helicopters and high speed aircraft such as the [[Lockheed SR-71 Blackbird]].<ref>{{cite magazine|url=http://www.time.com/time/magazine/article/0,9171,834721,00.html|archive-url=https://web.archive.org/web/20080308015232/http://www.time.com/time/magazine/article/0,9171,834721,00.html|url-status=dead|archive-date=8 March 2008|title=Here Comes the Flying Stovepipe |magazine=TIME|access-date=22 July 2011| date=26 November 1965}}</ref><ref>{{cite web| title = the heart of the SR-71 "Blackbird" : the mighty J-58 engine| publisher = aérostories| url = http://aerostories.free.fr/technique/J58/J58_01/page9.html| access-date = 22 July 2011}}</ref>

Rocket engines are primarily used on rockets, rocket sleds and experimental aircraft. Rocket engines are extremely powerful. The heaviest vehicle ever to leave the ground, the [[Saturn V]] rocket, was powered by five [[F-1 (rocket engine)|F-1 rocket engines]] generating a combined 180 million horsepower<ref>{{cite web| title = Historical Timeline| publisher = [[NASA]]| url = http://www.nasa.gov/centers/kennedy/about/history/timeline/1950_prt.htm| access-date = 22 July 2011| archive-date = 20 April 2021| archive-url = https://web.archive.org/web/20210420140904/https://www.nasa.gov/centers/kennedy/about/history/timeline/1950_prt.htm| url-status = dead}}</ref> (134.2 gigawatt). Rocket engines also have no need to "push off" anything, a fact that the [[New York Times]] [[Robert H. Goddard#New York Times editorial|denied in error]]. Rocket engines can be particularly simple, sometimes consisting of nothing more than a catalyst, as in the case of a [[hydrogen peroxide]] rocket.<ref>{{cite web| title = Can you make a rocket engine using hydrogen peroxide and silver?| publisher = [[How Stuff Works]]| url = http://www.howstuffworks.com/question159.htm| access-date = 22 July 2011| date = April 2000}}</ref> This makes them an attractive option for vehicles such as jet packs. Despite their simplicity, rocket engines are often dangerous and susceptible to explosions. The fuel they run off may be flammable, poisonous, corrosive or cryogenic. They also suffer from poor efficiency. For these reasons, rocket engines are only used when absolutely necessary.{{Citation needed|date=July 2011}}

Electric motors are used in [[electric vehicle]]s such as [[electric bicycle]]s, electric scooters, small boats, subways, [[Electric locomotive|trains]], [[trolleybus]]es, [[tram]]s and [[electric aircraft|experimental aircraft]]. Electric motors can be very efficient: over 90% efficiency is common.<ref>NEMA Design B electric motor standard, cited in [http://www.engineeringtoolbox.com/electrical-motor-efficiency-d_655.html Electrical Motor Efficiency] Retrieved 22 July 2011.</ref> Electric motors can also be built to be powerful, reliable, low-maintenance and of any size. Electric motors can deliver a range of speeds and torques without necessarily using a gearbox (although it may be more economical to use one). Electric motors are limited in their use chiefly by the difficulty of supplying electricity.{{Citation needed|date=July 2011}}

Compressed gas motors have been used on some vehicles experimentally. They are simple, efficient, safe, cheap, reliable and operate in a variety of conditions. One of the difficulties met when using gas motors is the cooling effect of expanding gas. These engines are limited by how quickly they absorb heat from their surroundings.<ref>{{cite web| title = Pneumatic Engine| publisher = Quasiturbine| url = http://sites.google.com/site/quasiturbines/enginetypes/etypepneumatic| access-date = 22 July 2011| archive-date = 4 June 2011| archive-url = https://web.archive.org/web/20110604010005/http://sites.google.com/site/quasiturbines/enginetypes/etypepneumatic| url-status = dead}}</ref> The cooling effect can, however, double as air conditioning. Compressed gas motors also lose effectiveness with falling gas pressure.{{Citation needed|date=November 2021}}<!--http://quasiturbine.promci.qc.ca/EProductQT600SCPneumatic.htm: not sure if that graph is proof of this sentence but I think it's self evident that lower pressure = lower torque in these engines-->

[[Ion thrusters]] are used on some satellites and spacecraft. They are only effective in a vacuum, which limits their use to spaceborne vehicles. Ion thrusters run primarily off electricity, but they also need a propellant such as [[caesium]], or, more recently [[xenon]].<ref>{{cite web| title = Fact Sheet| publisher = [[NASA]]| url = http://www.nasa.gov/centers/glenn/about/fs08grc.html| archive-url = https://web.archive.org/web/20041208225443/http://www.nasa.gov/centers/glenn/about/fs08grc.html| url-status = dead| archive-date = 8 December 2004| access-date = 22 July 2011}}</ref><ref>{{cite web| title = NASA – Innovative Engines| publisher = [[Boeing]], Xenon Ion Propulsion Center| url = http://www.boeing.com/defense-space/space/bss/factsheets/xips/xips.html| access-date = 22 July 2011| archive-url = https://web.archive.org/web/20110712022654/http://www.boeing.com/defense-space/space/bss/factsheets/xips/xips.html| archive-date = 12 July 2011| url-status = dead| df = dmy-all}}</ref> Ion thrusters can achieve extremely high speeds and use little propellant; however, they are power-hungry.<ref>{{cite web| title = Frequently asked questions about ion propulsion| publisher = [[NASA]]| url = http://nmp.nasa.gov/ds1/tech/ionpropfaq.html| archive-url = https://web.archive.org/web/20041023214440/http://nmp.nasa.gov/ds1/tech/ionpropfaq.html| url-status = dead| archive-date = 23 October 2004| access-date = 22 July 2011}}</ref>

=== Converting energy to work ===
The mechanical energy that motors and engines produce must be converted to [[Work (physics)|work]] by wheels, propellers, nozzles, or similar means.
Aside from converting mechanical energy into motion, wheels allow a vehicle to roll along a surface and, with the exception of railed vehicles, to be steered.<ref name="steering">{{cite web| title = How Car Steering Works| work = [[HowStuffWorks]]| url = http://www.howstuffworks.com/steering.htm| access-date = 23 July 2011| date = 2001-05-31}}</ref> Wheels are ancient technology, with specimens being discovered from over 5000 years ago.<ref>{{cite web| title = World's Oldest Wheel Found in Slovenia| url = http://www.ukom.gov.si/en/media_relations/background_information/culture/worlds_oldest_wheel_found_in_slovenia/| date = March 2003| publisher = Government Communication Office of the Republic of Slovenia| author = Alexander Gasser| access-date = 23 July 2011| url-status = dead| archive-url = https://web.archive.org/web/20120714033224/http://www.ukom.gov.si/en/media_relations/background_information/culture/worlds_oldest_wheel_found_in_slovenia/| archive-date = 14 July 2012| df = dmy-all}}</ref> Wheels are used in a plethora of vehicles, including motor vehicles, [[armoured personnel carrier]]s, amphibious vehicles, airplanes, trains, skateboards and wheelbarrows.

Nozzles are used in conjunction with almost all reaction engines.<ref name="nozzle">{{cite web| title = Nozzles| publisher = [[NASA]]| url = http://www.grc.nasa.gov/WWW/K-12/airplane/nozzle.html| access-date = 22 July 2011| archive-date = 31 May 2012| archive-url = https://web.archive.org/web/20120531093711/http://www.grc.nasa.gov/WWW/k-12/airplane/nozzle.html| url-status = dead}}</ref> Vehicles using nozzles include jet aircraft, rockets, and [[personal watercraft]]. <!--While nozzles are not strictly necessary to produce thrust, they do increase thrust by a great deal.--> While most nozzles take the shape of a cone or [[de Laval nozzle|bell]],<ref name="nozzle"/> some unorthodox designs have been created such as the [[Aerospike engine|aerospike]]. Some nozzles are intangible, such as the electromagnetic field nozzle of a vectored ion thruster.<ref>{{cite web| title = LTI-20 Flight Dynamics| publisher = Lightcraft Technologies International| url = http://www.lightcrafttechnologies.com/rpi_www/technical/flight_dynamics.html| access-date = 22 July 2011| quote = The ion thrusters use electromagnetic fields to vector the engine exhaust| archive-date = 13 March 2012| archive-url = https://web.archive.org/web/20120313031132/http://www.lightcrafttechnologies.com/rpi_www/technical/flight_dynamics.html| url-status = dead}}</ref>

[[Continuous track]] is sometimes used instead of wheels to power land vehicles. Continuous track has the advantages of a larger contact area, easy repairs on small damage, and high maneuverability.<ref>{{cite web| title = Week 04 – Continuous Track| publisher = Military Times| url = http://militarytimes.com/blogs/warrior-made/innovations/continuous-track/| access-date = 23 July 2011}}</ref> Examples of vehicles using continuous tracks are tanks, snowmobiles and excavators. Two continuous tracks used together allow for steering. The largest land vehicle in the world,<ref>{{cite web| title = The Biggest (and Hungriest) Machines| publisher = Dark Roasted Blend| url = http://www.darkroastedblend.com/2006/11/biggest-and-hungriest-machines.html| access-date = 23 July 2011}}</ref> the [[Bagger 293]], is propelled by continuous tracks.

Propellers (as well as screws, fans and rotors) are used to move through a fluid. Propellers have been used as toys since ancient times; however, it was [[Leonardo da Vinci]] who devised what was one of the earliest propeller driven vehicles, the "aerial-screw".<ref>{{cite web| title = Early Helicopter Technology| publisher = U.S. Centennial of Flight Commission| url = http://www.centennialofflight.gov/essay/Rotary/early_helicopters/HE1.htm| access-date = 23 July 2011| archive-url = https://web.archive.org/web/20110821031541/http://www.centennialofflight.gov/essay/Rotary/early_helicopters/HE1.htm| archive-date = 21 August 2011| url-status = dead| df = dmy-all}}</ref> In 1661, Toogood & Hays adopted the screw for use as a ship propeller.<ref>{{cite web| title = Brief History of Screw Development| publisher = Rod Sampson – School of Marine Science and Technology, [[Newcastle University]]| page = 10| url = http://research.ncl.ac.uk/cavitation/archive/MAR2010%20-%20propeller%20history.pdf| access-date = 23 July 2011| date = 5 February 2008| archive-date = 7 November 2015| archive-url = https://web.archive.org/web/20151107002835/http://research.ncl.ac.uk/cavitation/archive/MAR2010%20-%20propeller%20history.pdf| url-status = dead}}</ref> Since then, the propeller has been tested on many terrestrial vehicles, including the [[Schienenzeppelin]] train and numerous cars.<ref>{{cite web| title = Cars with Propellers: an Illustrated Overview| publisher = Dark Roasted Blend| url = http://www.darkroastedblend.com/2008/12/cars-with-propellers-essential.html| access-date = 23 July 2011}}{{Dead link|date=March 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> In modern times, propellers are most prevalent on watercraft and aircraft, as well as some amphibious vehicles such as hovercraft and [[ground-effect vehicle]]s. Intuitively, propellers cannot work in space as there is no working fluid; however, some sources have suggested that since [[vacuum state|space is never empty]], a propeller could be made to work in space.<ref>{{cite web| title = Vacuum Propellers| author = John Walker| publisher = Fourmilab Switzerland| url = http://www.fourmilab.ch/documents/vprop/| access-date = 23 July 2011| author-link = John Walker (programmer)}}</ref>

Similarly to propeller vehicles, some vehicles use wings for propulsion. Sailboats and sailplanes are propelled by the forward component of lift generated by their sails/wings.<ref>{{cite web| title = How Sailboats Move in the Water| work = [[HowStuffWorks]]| url = http://adventure.howstuffworks.com/outdoor-activities/water-sports/sailboat3.htm| access-date = 2 August 2011| date = 2008-03-11}}</ref><ref>{{cite web| title = Three Forces on a Glider| work = [[NASA]]| url = http://www.grc.nasa.gov/WWW/K-12/airplane/glidfor.html| access-date = 2 August 2011| archive-date = 15 April 2021| archive-url = https://web.archive.org/web/20210415211536/https://www.grc.nasa.gov/WWW/K-12/airplane/glidfor.html| url-status = dead}}</ref> [[Ornithopter]]s also produce thrust aerodynamically. Ornithopters with large rounded leading edges produce lift by leading-edge suction forces.<ref>{{cite web | title = How It Works | publisher = Project Ornithopter | url = http://www.ornithopter.net/how_it_works_e.html| access-date = 2 August 2011}}</ref> Research at the University of Toronto Institute for Aerospace Studies<ref>{{cite web | title = University of Toronto Institute for Aerospace Studies| url = https://www.utias.utoronto.ca/tag/ornitopter/ | access-date = 10 November 2022}}</ref> lead to a flight with an actual ornithopter on July 31, 2010.

Paddle wheels are used on some older watercraft and their reconstructions. These ships were known as [[paddle steamer]]s. Because paddle wheels simply push against the water, their design and construction is very simple. The oldest such ship in scheduled service is the [[Skibladner]].<ref>{{cite web| title = Skibladner: the world's oldest paddle steamer| work = [[Skibladner]]| url = http://www.skibladner.no/engelsk/index.htm| access-date = 2 August 2011| url-status = dead| archive-url = https://web.archive.org/web/20110809043151/http://www.skibladner.no/engelsk/index.htm| archive-date = 9 August 2011| df = dmy-all}}</ref> Many [[pedalo]] boats also use paddle wheels for propulsion.

[[Screw-propelled vehicle]]s are propelled by [[auger (drill)|auger]]-like cylinders fitted with helical flanges. Because they can produce thrust on both land and water, they are commonly used on all-terrain vehicles. The [[ZiL#Models|ZiL-2906]] was a Soviet-designed screw-propelled vehicle designed to retrieve cosmonauts from the Siberian wilderness.<ref>{{cite web| title = Véhicules Insolites (Strange Vehicles)| language = fr| author = Jean Pierre Dardinier| publisher = Fédération Française des Groupes de Conservation de Véhicules Militaires| url = http://mvcgfrance.org/vzil.htm| access-date = 23 July 2011| url-status = dead| archive-url = https://web.archive.org/web/20111202213122/http://mvcgfrance.org/vzil.htm| archive-date = 2 December 2011| df = dmy-all}}</ref>

=== Friction ===
All or almost all of the useful energy produced by the engine is usually dissipated as friction; so minimizing frictional losses is very important in many vehicles. The main sources of friction are [[rolling friction]] and [[drag (physics)|fluid drag]] (air drag or water drag).

Wheels have low bearing friction, and pneumatic tires give low rolling friction. Steel wheels on steel tracks are lower still.<ref>{{cite web|last=Nice |first=Karim |url=http://auto.howstuffworks.com/tire4.htm |title=HowStuffWorks – How Tires Work |publisher=Auto.howstuffworks.com |date=19 September 2000 |access-date=8 January 2013}}</ref>

[[Aerodynamic drag]] can be reduced by streamlined design features.

Friction is desirable and important in supplying [[traction (engineering)|traction]] to facilitate motion on land. Most land vehicles rely on friction for accelerating, decelerating and changing direction. Sudden reductions in traction can cause loss of control and accidents.