Editing Vehicle (section)

=== 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intermittent internal combustion engines were once the primary means of aircraft propulsion, they have been largely superseded by continuous internal combustion engines, such as [[gas turbine]]s. Turbine engines are light and, particularly when used on aircraft, efficient.{{Citation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>