Examine individual changes

'{{other uses}} {{redirect|Petrol}} {{Use American English|date=April 2016}} {{Use dmy dates|date=May 2017}} [[File:GasStationHiroshima.jpg|thumb|upright=1.35|A [[Royal Dutch Shell|Shell]] gasoline station in [[Hiroshima]], [[Japan]]]] '''Gasoline''' ([[American English]]) or '''petrol''' ([[British English]]) is a transparent [[petroleum]]-derived liquid that is used primarily as a [[fuel]] in [[spark-ignition engine|spark-ignited]] [[internal combustion engine]]s. It consists mostly of [[organic compound]]s obtained by the [[fractional distillation]] of petroleum, enhanced with a variety of [[gasoline additive|additives]]. On average, a {{convert|42|gal|liter|adj=on|abbr=off}} [[Oil barrel|barrel of crude oil]] yields about {{convert|19|gal|liter|abbr=off}} of gasoline after processing in an [[oil refinery]], though this varies based on the [[crude oil assay]]. The characteristic of a particular gasoline blend to resist igniting too early (which causes [[engine knocking|knocking]] and reduces efficiency in reciprocating engines) is measured by its [[octane rating]]. Gasoline is produced in several grades of octane rating. [[Tetraethyllead]] and other lead compounds are no longer used in most areas to increase octane rating. Other chemicals are frequently added to gasoline to improve chemical stability and performance characteristics, control corrosiveness and provide fuel system cleaning. Gasoline may contain oxygen-containing chemicals such as [[ethanol]], [[MTBE]] or [[ETBE]] to improve combustion. Gasoline used in internal combustion engines has a significant effect on the environment, both in local effects (e.g., [[smog]]) and in global effects (e.g., [[climate change|effect on the climate]]). Gasoline can also enter the environment uncombusted, both as liquid and as vapor, from leakage and handling during production, transport and delivery (e.g., from storage tanks, from spills, etc.). As an example of efforts to control such leakage, many (underground) storage tanks are required to have extensive measures in place to detect and prevent such leaks.<ref>{{Cite web|url=https://www.epa.gov/ust/preventing-and-detecting-underground-storage-tank-ust-releases|title=Preventing and Detecting Underground Storage Tank (UST) Releases {{!}} US EPA|last=EPA,OSWER|first=US|website=US EPA|language=en|access-date=2018-06-18}}</ref> Gasoline contains [[benzene]] and other known [[carcinogen]]s.<ref>{{cite web|url=http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=36176#Download|title=Evaluation of the Carcinogenicity of Unleaded Gasoline|work=epa.gov|deadurl=no|archiveurl=https://web.archive.org/web/20100627032708/http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=36176#Download|archivedate=27 June 2010|df=dmy-all}}</ref><ref>{{cite journal|last1=Mehlman|first1=MA|title=Dangerous properties of petroleum-refining products: carcinogenicity of motor fuels (gasoline).|journal=Teratogenesis, carcinogenesis, and mutagenesis|date=1990|volume=10|issue=5|pages=399–408|pmid=1981951}}</ref><ref>{{cite journal|last1=Baumbach|first1=JI|last2=Sielemann|first2=S|last3=Xie|first3=Z|last4=Schmidt|first4=H|title=Detection of the gasoline components methyl tert-butyl ether, benzene, toluene, and m-xylene using ion mobility spectrometers with a radioactive and UV ionization source.|journal=Analytical Chemistry|date=15 March 2003|volume=75|issue=6|pages=1483–90|pmid=12659213|doi=10.1021/ac020342i}}</ref> ==Etymology== "Gasoline" is a North American word that refers to fuel for [[automobile]]s. The ''Oxford English Dictionary'' dates its first recorded use to 1863 when it was spelled "gasolene". The term "gasoline" was first used in North America in 1864.<ref>See: * [https://blog.oxforddictionaries.com/2012/04/11/the-origin-of-gasoline/ Oxford Dictionaries (blog): The etymology of gasoline] * 38th Congress. Sessions I. Chapter 173: An Act to provide Internal Revenue to support the Government, to pay Interest on the Public Debt, and for other Purposes, 1864, p.265. From p. 265: " … ; ''And provided, also,'' That naphtha of specific gravity exceeding eighty degrees, according to Baume's hydrometer, and of the kind usually known as gasoline, shall be subject to a tax of five per centum ad valorem." See [https://www.loc.gov/law/help/statutes-at-large/38th-congress/session-1/c38s1ch173.pdf Library of Congress (U.S.A.)] * See also: Stevens, Levi, [http://pdfpiw.uspto.gov/.piw?docid=00045568&PageNum=1&IDKey=16AA8FEE495E "Improved apparatus for vaporizing and aerating volatile hydrocarbon,"] U.S. Patent no. 45,568 (issued: 20 December 1864). From p.2 of the text: "One of the products obtained from the distillation of petroleum is a colorless liquid having an ethereal odor and being the lightest in specific gravity of all known liquids. This material is known now in commerce by the term "gasoline." "</ref> The word is a derivation from the word "gas" and the chemical suffixes "-ol" and "-ine" or "-ene".<ref name="oed">'''gasoline,''' ''n.'', and '''gasoline,''' ''n.,'' Oxford English Dictionary online edition</ref> However, the term may also have been influenced by the trademark "Cazeline" or "Gazeline". On 27 November 1862, the British publisher, coffee merchant and social campaigner [[John Cassell]] placed an advertisement in ''[[The Times]]'' of London: {{quote|The Patent Cazeline Oil, safe, economical, and brilliant … possesses all the requisites which have so long been desired as a means of powerful artificial light.<ref name="The etymology of gasoline">{{cite web|title=The etymology of gasoline|url=http://blog.oxforddictionaries.com/2012/04/the-origin-of-gasoline/|website=[[Oxford English Dictionary]]|accessdate=30 July 2017|deadurl=no|archiveurl=https://web.archive.org/web/20170729091400/http://blog.oxforddictionaries.com/2012/04/the-origin-of-gasoline/|archivedate=29 July 2017|df=dmy-all}}</ref>}} This is the earliest occurrence of the word to have been found. Cassell discovered that a shopkeeper in Dublin named Samuel Boyd was selling counterfeit cazeline and wrote to him to ask him to stop. Boyd did not reply and changed every ‘C’ into a ‘G’, thus coining the word "gazeline".<ref name="The etymology of gasoline">{{cite web|title=The etymology of gasoline|url=http://blog.oxforddictionaries.com/2012/04/the-origin-of-gasoline/|website=[[Oxford English Dictionary]]|accessdate=30 July 2017|deadurl=no|archiveurl=https://web.archive.org/web/20170729091400/http://blog.oxforddictionaries.com/2012/04/the-origin-of-gasoline/|archivedate=29 July 2017|df=dmy-all}}</ref> The name "petrol" is used in place of "gasoline" in most Commonwealth countries. "Petrol" was first used as the name of a refined petroleum product around 1870 by British wholesaler [[Carless Refining and Marketing Ltd|Carless, Capel & Leonard]], who marketed it as a [[solvent]].<ref>"[https://web.archive.org/web/20110628204613/http://vintagegarage.co.uk/histories/carless%20capel%20%26%20leonard.htm Carless, Capel & Leonard]", vintagegarage.co.uk, accessed 5 August 2012</ref> When the product later found a new use as a motor fuel, [[Frederick Richard Simms|Frederick Simms]], an associate of [[Gottlieb Daimler]], suggested to Carless that they register the trademark "petrol",<ref>"[http://www.nationalarchives.gov.uk/a2a/records.aspx?cat=084-dbccl&cid=0#0 Carless, Capel and Leonard Ltd Records: Administrative History] {{webarchive|url=https://web.archive.org/web/20130629214535/http://www.nationalarchives.gov.uk/a2a/records.aspx?cat=084-dbccl&cid=0 |date=29 June 2013 }}", The National Archives, accessed 5 August 2012</ref> but by this time the word was already in general use, possibly inspired by the French ''pétrole'',<ref name="oed"/> and the registration was not allowed. Carless registered a number of alternative names for the product, but "petrol" nonetheless became the common term for the fuel in the British Commonwealth.<ref name=etymonline>{{cite web|url=http://www.etymonline.com/index.php?search=gasoline|title=Online Etymology Dictionary|work=etymonline.com|deadurl=no|archiveurl=https://web.archive.org/web/20060109025338/http://www.etymonline.com/index.php?search=gasoline|archivedate=9 January 2006|df=dmy-all}}</ref><ref>{{Cite journal| journal = Chrysler Collector | issue = 154 | year = 2004 | pages = 16–20 | first=Ron | last=Hincks | title = Our Motoring Heritage: gasoline & Oil}}</ref> British refiners originally used "motor spirit" as a generic name for the automotive fuel and "aviation spirit" for [[avgas|aviation gasoline]]. When Carless was denied a trademark on "petrol" in the 1930s, its competitors switched to the more popular name "petrol". However, "motor spirit" had already made its way into laws and regulations, so the term remains in use as a formal name for petrol.<ref>{{cite news|last1=Kemp|first1=John|title=India's thirst for gasoline helps spur global oil demand: Kemp|url=https://www.reuters.com/article/india-gasoline-kemp-idUSL5N16Q3EX|work=Reuters|date=18 March 2017|quote=India's drivers used 500,000 barrels per day of motor spirit in the 12 months ending in February 2016, according to the Petroleum Planning and Analysis Cell of the Ministry of Petroleum.|deadurl=no|archiveurl=https://web.archive.org/web/20170830214917/https://www.reuters.com/article/india-gasoline-kemp-idUSL5N16Q3EX|archivedate=30 August 2017|df=dmy-all}}</ref><ref>{{cite book|author1=National Energy Advisory Committee (Australia)|title=Motor Spirit: Vehicle Emissions, Octane Ratings and Lead Additives: Further Examination, March 1981|publisher=Australian Government Publishing Service|isbn=9780642066725|page=11|url=https://books.google.com/books?id=x0ANAQAAIAAJ|language=en|quote=Based on estimated provided by the oil refining industry, the Department of National Development and Energy has estimated that the decision to reduce the RON of premium motor spirit from 98 to 97 has resulted in an annual saving equivalent to about 1.6 million barrels of crude oil.|deadurl=no|archiveurl=https://web.archive.org/web/20170217140909/https://books.google.com/books?id=x0ANAQAAIAAJ|archivedate=17 February 2017|df=dmy-all}}</ref> The term is used most widely in Nigeria, where the largest petroleum companies call their product "premium motor spirit".<ref>{{cite web|title=Premium Motor Spirit|url=http://www.oandoplc.com/oando-marketing/products/premium-motor-spirits/|publisher=Oando PLC|deadurl=yes|archiveurl=https://web.archive.org/web/20170217070556/http://www.oandoplc.com/oando-marketing/products/premium-motor-spirits/|archivedate=17 February 2017|df=dmy-all}}</ref> Although "petrol" has made inroads into Nigerian English, "premium motor spirit" remains the formal name that is used in scientific publications, government reports, and newspapers.<ref>{{cite journal|last1=Udonwa|first1=N. E.|last2=Uko|first2=E. K.|last3=Ikpeme|first3=B. M.|last4=Ibanga|first4=I. A.|last5=Okon|first5=B. O.|title=Exposure of Petrol Station Attendants and Auto Mechanics to Premium Motor Sprit Fumes in Calabar, Nigeria|journal=Journal of Environmental and Public Health|date=2009|volume=2009|doi=10.1155/2009/281876|pmc=2778824|pmid=19936128|pages=1–5}}</ref> The use of the word ''gasoline'' instead of ''petrol'' outside North America can often be confusing. Shortening ''gasoline'' to ''gas'', which happens often, causes confusion with various forms of [[gas]]eous products also used as automotive fuel (for example, [[Compressed natural gas|compressed natural gas (CNG)]], [[liquefied natural gas|liquefied natural gas (LNG)]] and [[liquefied petroleum gas|liquefied petroleum gas (LPG)]]). In many countries, gasoline has a colloquial name derived from that of the chemical [[benzene]] (e.g., German ''Benzin'', Czech ''benzín'', Dutch ''benzine'', Italian ''benzina'', Russian бензин ''benzin'', Polish ''benzyna'', Chilean Spanish ''bencina'', Thai เบนซิน ''bensin'', Greek βενζίνη ''venzini'', Romanian ''benzină'', Hebrew בנזין ''benzin'', Swedish ''bensin'', Arabic بنزين ''binzīn'', and Catalan ''benzina''). Argentina, Uruguay and Paraguay use the colloquial name ''nafta'' derived from that of the chemical [[naphtha]].<ref>{{cite web|url=http://www.spanishdict.com/translate/nafta|title=Nafta in English – Spanish to English Translation|work=SpanishDict|deadurl=no|archiveurl=https://web.archive.org/web/20100206210120/http://www.spanishdict.com/translate/nafta|archivedate=6 February 2010|df=dmy-all}}</ref> ==History== ===Prior to 1903=== The first internal combustion engines suitable for use in transportation applications, so-called [[Otto engine]]s, were developed in Germany during the last quarter of the 19th century. The fuel for these early engines was a relatively volatile [[hydrocarbon]] obtained from [[coal gas]]. With a [[boiling point]] near {{convert|85|°C|°F}} ([[octane]]s boil about 40&nbsp;°C higher), it was well-suited for early [[carburetor]]s (evaporators). The development of a "spray nozzle" carburetor enabled the use of less volatile fuels. Further improvements in engine efficiency were attempted at higher [[compression ratio]]s, but early attempts were blocked by the premature explosion of fuel, known as [[engine knocking|knocking]]. In 1891, the [[Shukhov cracking process]] became the world's first commercial method to break down heavier hydrocarbons in crude oil to increase the percentage of lighter products compared to simple distillation. ===1903 to 1914=== The evolution of gasoline followed the evolution of oil as the dominant source of energy in the industrializing world. Prior to World War One, Britain was the world's greatest industrial power and depended on its navy to protect the shipping of raw materials from its colonies. Germany was also industrializing and, like Britain, lacked many natural resources which had to be shipped to the home country. By the 1890s, Germany began to pursue a policy of global prominence and began building a navy to compete with Britain's. Coal was the fuel that powered their navies. Though both Britain and Germany had natural coal reserves, new developments in oil as a fuel for ships changed the situation. Coal-powered ships were a tactical weakness because the process of [[coaling (ships)|loading coal]] was extremely slow and dirty and left the ship completely vulnerable to attack, and unreliable supplies of coal at international ports made long-distance voyages impractical. The advantages of petroleum oil soon found the navies of the world converting to oil, but Britain and Germany had very few domestic oil reserves.<ref>Daniel Yergen, ''The Prize, The Epic Quest for Oil, Money & Power'', Simon & Schuster, 1992, pp. 150–163.</ref> Britain eventually solved its naval oil dependence by securing oil from [[Royal Dutch Shell]] and the [[Anglo-Persian Oil Company]] and this determined from where and of what quality its gasoline would come. During the early period of gasoline engine development, aircraft were forced to use motor vehicle gasoline since aviation gasoline did not yet exist. These early fuels were termed "straight-run" gasolines and were byproducts from the distillation of a single crude oil to produce [[kerosene]], which was the principal product sought for burning in [[kerosene lamp]]s. Gasoline production would not surpass kerosene production until 1916. The earliest straight-run gasolines were the result of distilling eastern crude oils and there was no mixing of distillates from different crudes. The composition of these early fuels was unknown and the quality varied greatly as crude oils from different oil fields emerged in different mixtures of hydrocarbons in different ratios. The engine effects produced by abnormal combustion ([[engine knocking]] and [[pre-ignition]]) due to inferior fuels had not yet been identified, and as a result there was no rating of gasoline in terms of its resistance to abnormal combustion. The general specification by which early gasolines were measured was that of [[specific gravity]] via the [[Baumé scale]] and later the [[volatility (chemistry)|volatility]] (tendency to vaporize) specified in terms of boiling points, which became the primary focuses for gasoline producers. These early eastern crude oil gasolines had relatively high Baumé test results (65 to 80 degrees Baumé) and were called Pennsylvania "High-Test" or simply "High-Test" gasolines. These would often be used in aircraft engines. By 1910, increased automobile production and the resultant increase in gasoline consumption produced a greater demand for gasoline. Also, the growing electrification of lighting produced a drop in kerosene demand, creating a supply problem. It appeared that the burgeoning oil industry would be trapped into over-producing kerosene and under-producing gasoline since simple distillation could not alter the ratio of the two products from any given crude. The solution appeared in 1911 when the development of the [[Burton process]] allowed [[thermal cracking]] of crude oils, which increased the percent yield of gasoline from the heavier hydrocarbons. This was combined with expansion of foreign markets for the export of surplus kerosene which domestic markets no longer needed. These new thermally "cracked" gasolines were believed to have no harmful effects and would be added to straight-run gasolines. There also was the practice of mixing heavy and light distillates to achieve a desired Baumé reading and collectively these were called "blended" gasolines.<ref name="Matthew Van Winkle 1944, pp. 1">Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, pp. 1–4.</ref> Gradually, volatility gained favor over the Baumé test, though both would continue to be used in combination to specify a gasoline. As late as June 1917, [[Standard Oil]] (the largest refiner of crude oil in the United States at the time) stated that the most important property of a gasoline was its volatility.<ref>https://play.google.com/books/reader?id=bKo7AQAAMAAJ&printsec=frontcover&pg=GBS.PP1</ref> It is estimated that the rating equivalent of these straight-run gasolines varied from 40 to 60 octane and that the "High-Test" (sometimes referred to as "fighting grade") probably averaged 50 to 65 octane.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 10.</ref> ===World War I=== Prior to the [[American entry into World War I]], the European Allies used fuels derived from crude oils from Borneo, Java and Sumatra, which gave satisfactory performance in their military aircraft. When the United States entered the war in April 1917, the U.S. became the principal supplier of aviation gasoline to the Allies and a decrease in engine performance was noted.<ref>https://play.google.com/books/reader?id=lo9TAAAAMAAJ&printsec=frontcover&output=reader&hl=en&pg=GBS.PA575 p.569</ref> Soon it was realized that motor vehicle fuels were unsatisfactory for aviation, and after the loss of a number of combat aircraft, attention turned to the quality of the gasolines being used. Later flight tests conducted in 1937 showed that an octane reduction of 13 points (from 100 down to 87 octane) decreased engine performance by 20 percent and increased take-off distance by 45 percent.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 252</ref> If abnormal combustion were to occur, the engine could lose enough power to make getting airborne impossible and a take-off roll became a threat to the pilot and aircraft. On 2 August 1917, the [[United States Bureau of Mines]] arranged to study fuels for aircraft in cooperation with the Aviation Section of the [[U.S. Army Signal Corps]] and a general survey concluded that no reliable data existed for the proper fuels for aircraft. As a result, flight tests began at Langley, McCook and Wright fields to determine how different gasolines performed under different conditions. These tests showed that in certain aircraft, motor vehicle gasolines performed as well as "High-Test" but in other types resulted in hot-running engines. It was also found that gasolines from aromatic and naphthenic base crude oils from California, South Texas and Venezuela resulted in smooth-running engines. These tests resulted in the first government specifications for motor gasolines (aviation gasolines used the same specifications as motor gasolines) in late 1917.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 3.</ref> ===United States, 1918–1929=== Engine designers knew that, according to the [[Otto cycle]], power and efficiency increased with compression ratio, but experience with early gasolines during World War I showed that higher compression ratios increased the risk of abnormal combustion, producing lower power, lower efficiency, hot-running engines and potentially severe engine damage. To compensate for these poor fuels, early engines used low compression ratios, which required relatively large, heavy engines to produce limited power and efficiency. The [[Wright brothers]]' first gasoline engine used a compression ratio as low as 4.7-to-1, developed only {{convert|12|hp}} from {{convert|201|cuin|cc}} and weighed {{convert|180|lb|kg}}.<ref>http://www.wright-brothers.org/Information_Desk/Just_the_Facts/Engines_&_Props/1903_Engine.htm</ref><ref>https://www.scribd.com/document/111256746/Evaluation-of-Wright-Flyer-s-Engine</ref> This was a major concern for aircraft designers and the needs of the aviation industry provoked the search for fuels that could be used in higher-compression engines. Between 1917 and 1919, the amount of thermally cracked gasoline utilized almost doubled. Also, the use of [[natural gasoline]] increased greatly. During this period, many U.S. states established specifications for motor gasoline but none of these agreed and were unsatisfactory from one standpoint or another. Larger oil refiners began to specify [[saturated and unsaturated compounds|unsaturated]] material percentage (thermally cracked products caused gumming in both use and storage and unsaturated hydrocarbons are more reactive and tend to combine with impurities leading to gumming). In 1922, the U.S. government published the first specifications for aviation gasolines (two grades were designated as "Fighting" and "Domestic" and were governed by boiling points, color, sulphur content and a gum formation test) along with one "Motor" grade for automobiles. The gum test essentially eliminated thermally cracked gasoline from aviation usage and thus aviation gasolines reverted to fractionating straight-run naphthas or blending straight-run and highly treated thermally cracked naphthas. This situation persisted until 1929.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, pp. 6–9.</ref> The automobile industry reacted to the increase in thermally cracked gasoline with alarm. Thermal cracking produced large amounts of both [[olefin|mono-]] and [[diolefin]]s (unsaturated hydrocarbons), which increased the risk of gumming.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 74.</ref> Also the volatility was decreasing to the point that fuel did not vaporize and was sticking to [[spark plug]]s and fouling them, creating hard starting and rough running in winter and sticking to cylinder walls, bypassing the pistons and rings and going into the crankcase oil.<ref>J. G. Vincent, ''Adapting Engines to the Use of Available Fuels'', The Journal of the Society of Automotive Engineers, November 1919, p. 346. https://play.google.com/store/books/details?id=Gcg6AQAAMAAJ&rdid=book-Gcg6AQAAMAAJ&rdot=1</ref> One journal stated, "...on a multi-cylinder engine in a high-priced car we are diluting the oil in the crankcase as much as 40 percent in a 200-mile run, as the analysis of the oil in the oil-pan shows."<ref>Joseph E. Pogue, ''The Engine-Fuel Problem'', The Journal of the Society of Automotive Engineers, September 1919, p. 232. https://play.google.com/store/books/details?id=Gcg6AQAAMAAJ&rdid=book-Gcg6AQAAMAAJ&rdot=1</ref> Being very unhappy with the consequent reduction in overall gasoline quality, automobile manufacturers suggested imposing a quality standard on the oil suppliers. The oil industry in turn accused the automakers of not doing enough to improve vehicle economy, and the dispute became known within the two industries as "The Fuel Problem". Animosity grew between the industries, each accusing the other of not doing anything to resolve matters, and relationships deteriorated. The situation was only resolved when the [[American Petroleum Institute]] (API) initiated a conference to address "The Fuel Problem" and a Cooperative Fuel Research (CFR) Committee was established in 1920 to oversee joint investigative programs and solutions. Apart from representatives of the two industries, the [[Society of Automotive Engineers]] (SAE) also played an instrumental role, with the [[U.S. Bureau of Standards]] being chosen as an impartial research organization to carry out many of the studies. Initially, all the programs were related to volatility and fuel consumption, ease of starting, crankcase oil dilution and acceleration.<ref>https://www.newcomen.com/wp-content/uploads/2012/12/Chapter-11-Marshall.pdf p. 227.</ref> ===Leaded gasoline controversy, 1924–1925=== With the increased use of thermally cracked gasolines came an increased concern regarding its effects on abnormal combustion, and this led to research for antiknock additives. In the late 1910s, researchers such as A.H. Gibson, [[Harry Ricardo]], [[Thomas Midgley Jr.]] and Thomas Boyd began to investigate abnormal combustion. Beginning in 1916, [[Charles F. Kettering]] began investigating additives based on two paths, the "high percentage" solution (where large quantities of [[ethanol]] were added) and the "low percentage" solution (where only 2–4 grams per gallon were needed). The "low percentage" solution ultimately led to the discovery of [[tetraethyllead]] (TEL) in December 1921, a product of the research of Midgley and Boyd. This innovation started a cycle of improvements in [[fuel efficiency]] that coincided with the large-scale development of oil refining to provide more products in the boiling range of gasoline. Ethanol could not be patented but TEL could, so Kettering secured a patent for TEL and began promoting it instead of other options. The dangers of compounds containing [[lead]] were well-established by then and Kettering was directly warned by Robert Wilson of MIT, Reid Hunt of Harvard, Yandell Henderson of Yale, and Charles Kraus of the University of Potsdam in Germany about its use. Kraus had worked on tetraethyllead for many years and called it "a creeping and malicious poison" that had killed a member of his dissertation committee.<ref>https://thewaternetwork.com/article-FfV/a-creeping-and-malicious-poison-W8Gx1ojp1oQjUZtgCKL1jQ</ref><ref name="pdfs.semanticscholar.org">https://pdfs.semanticscholar.org/5ef4/a42a4a5940ef6adf04aa1912147097aa3363.pdf</ref> On 27 October 1924, newspaper articles around the nation told of the workers at the Standard Oil refinery near [[Elizabeth, New Jersey]] who were producing TEL and were suffering from [[lead poisoning]]. By 30 October, the death toll had reached five.<ref name="pdfs.semanticscholar.org"/> In November, the New Jersey Labor Commission closed the Bayway refinery and a grand jury investigation was started which had resulted in no charges by February 1925. Leaded gasoline sales were banned in New York City, Philadelphia and New Jersey. [[General Motors]], [[DuPont]], and Standard Oil, who were partners in [[Ethyl Corporation]], the company created to produce TEL, began to argue that there were no alternatives to leaded gasoline that would maintain fuel efficiency and still prevent engine knocking. After flawed studies determined that TEL-treated gasoline was not a public health issue, the controversy subsided.<ref name="pdfs.semanticscholar.org"/> ===United States, 1930–1941=== In the five-year period prior to 1929, a great amount of experimentation was conducted on different testing methods for determining fuel resistance to abnormal combustion. It appeared engine knocking was dependent on a wide variety of parameters including compression, cylinder temperature, air-cooled or water-cooled engines, chamber shapes, intake temperatures, lean or rich mixtures and others. This led to a confusing variety of test engines that gave conflicting results, and no standard rating scale existed. By 1929, it was recognized by most aviation gasoline manufacturers and users that some kind of antiknock rating must be included in government specifications. In 1929, the [[octane rating]] scale was adopted, and in 1930 the first octane specification for aviation fuels was established. In the same year, the [[U.S. Army Air Force]] specified fuels rated at 87 octane for its aircraft as a result of studies it conducted.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 22.</ref> During this period, research showed that hydrocarbon structure was extremely important to the antiknocking properties of fuel. Straight-chain [[alkane|paraffins]] in the boiling range of gasoline had low antiknock qualities while ring-shaped molecules such as [[aromatic hydrocarbon]]s (an example is [[benzene]]) had higher resistance to knocking.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 20.</ref> This development led to the search for processes that would produce more of these compounds from crude oils than achieved under straight distillation or thermal cracking. Research by the major refiners into conversion processes yielded isomerization, dehydration, and alkylation that could change the cheap and abundant [[butane]] into [[isooctane]], which became an important component in aviation fuel blending. To further complicate the situation, as engine performance increased, the altitude that aircraft could reach also increased, which resulted in concerns about the fuel freezing. The average temperature decrease is {{convert|3.6|F-change}} per {{convert|1000|ft|m|adj=on|abbr=off}} increase in altitude, and at {{convert|40000|ft|km}}, the temperature can approach {{convert|-70|°F|°C}}. Additives like benzene, with a freezing point of {{convert|42|°F|°C}}, would freeze in the gasoline and plug fuel lines. Substitute aromatics such as [[toluene]], [[xylene]] and [[cumene]] combined with limited benzene solved the problem.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, p. 34.</ref> By 1935, there were seven different aviation grades based on octane rating, two Army grades, four Navy grades and three commercial grades including the introduction of 100-octane aviation gasoline. By 1937 the confusion increased to 14 different grades, in addition to 11 others in foreign countries. With some companies required to stock 14 grades of aviation fuel, none of which could be interchanged, the effect on the refiners was negative. The refining industry could not concentrate on large capacity conversion processes for so many different grades and a solution had to be found. By 1941, principally through the efforts of the Cooperative Fuel Research Committee, the number of grades for aviation fuels was reduced to three: 73, 91 and 100 octane.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, pp. 12–19.</ref> In 1937, [[Eugene Houdry]] developed the Houdry process of [[catalytic cracking]], which produced a high-octane base stock of gasoline which was superior to the thermally cracked product since it did not contain the high concentration of olefins.<ref name="Matthew Van Winkle 1944, pp. 1"/> In 1940, there were only 14 Houdry units in operation in the U.S.; by 1943, this had increased to 77, either of the Houdry process or of the Thermofor Catalytic or Fluid Catalyst type.<ref>Matthew Van Winkle, ''Aviation Gasoline Manufacture'', McGraw-Hill, 1944, pp. 94–95.</ref> ===World War II=== ===Germany=== Oil and its byproducts, especially high-octane aviation gasoline, would prove to be a driving concern for how Germany conducted the war. As a result of the lessons of World War I, Germany had stockpiled oil and gasoline for its [[blitzkrieg]] offensive and had annexed Austria, adding 18,000 barrels per day of oil production, but this was not sufficient to sustain the planned conquest of Europe. Because captured supplies and oil fields would be necessary to fuel the campaign, the German high command created a special squad of oil-field experts drawn from the ranks of domestic oil industries. They were sent in to put out oil-field fires and get production going again as soon as possible. But capturing oil fields remained an obstacle throughout the war. During the [[Invasion of Poland]], German estimates of gasoline consumption turned out to be vastly underestimated. [[Heinz Guderian]] and his [[Panzer division]]s consumed nearly {{convert|1000|gal|liter}} of gasoline per mile on the drive to [[Vienna]]. When they were engaged in combat across open country, gasoline consumption almost doubled. On the second day of battle, a unit of the XIX Corps was forced to halt when it ran out of gasoline.<ref>Robert W. Czeschin, ''The Last Wave; Oil, War, and Financial Upheaval in the 1990's'', Agora Inc., 1988, pp. 13–14.</ref> One of the major objectives of the Polish invasion was their oil fields but the Soviets invaded and captured 70 percent of the Polish production before the Germans could reach it. Through the [[German-Soviet Commercial Agreement (1940)]], Stalin agreed in vague terms to supply Germany with additional oil equal to that produced by now Soviet-occupied Polish oil fields at Drohobych and Boryslav in exchange for hard coal and steel tubing. Even after the Nazis conquered the vast territories of Europe, this did not help the gasoline shortage. This area had never been self-sufficient in oil before the war. In 1938, the area that would become Nazi-occupied would produce 575,000 barrels per day. In 1940, total production under German control amounted to only 234,550 barrels—a shortfall of 59 percent.<ref>Robert W. Czeschin, ''The Last Wave; Oil, War, and Financial Upheaval in the 1990's'', Agora Inc., 1988, p. 17.</ref> By the spring of 1941 and the depletion of German gasoline reserves, Hitler saw the invasion of Russia to seize the Polish oil fields and the Russian oil in the Caucasus as the solution to the German gasoline shortage. As early as July 1941, following the 22 June start of [[Operation Barbarossa]], certain Luftwaffe squadrons were forced to curtail ground support missions due to shortages of aviation gasoline. On 9 October, the German quartermaster general estimated that army vehicles were 24,000 barrels short of gasoline requirements.<ref>Robert W. Czeschin, ''The Last Wave; Oil, War, and Financial Upheaval in the 1990's'', Agora Inc., 1988, p. 19.</ref> ===Japan=== Japan, like Germany, had almost no domestic oil supply and by the late 1930s produced only 7% of its own oil while importing the rest - 80% from the United States. As Japanese aggression grew in China ( [[USS Panay incident]] ) and news reached the American public of Japanese bombing of civilian centers, especially the bombing of Chungking, public opinion began to support a U.S. embargo. A Gallup poll in June 1939 found that 72 percent of the American public supported an embargo on war materials to Japan. This increased tensions between the U.S. and Japan led to the U.S. placing restrictions on exports and in July 1940 the U.S. issued a proclamation that banned the export of 87 octane or higher aviation gasoline to Japan. This ban did not hinder the Japanese as their aircraft could operate with fuels below 87 octane and if needed they could add TEL to increase the octane. As it turned out, Japan bought 550 percent more sub-87 octane aviation gasoline in the five months after the July 1940 ban on higher octane sales.<ref>Daniel Yergin, The Prize, Simon & Schuster, 1992, p.310-312</ref> The possibility of a complete ban of gasoline from America created friction in the Japanese government as to what action to take to secure more supplies from the Dutch East Indies and demanded greater oil exports from the exiled Dutch government after the [[Battle of the Netherlands]]. This action prompted the U.S. to move its Pacific fleet from Southern California to Pearl Harbor to help stiffen British resolve to stay in Indochina. With the [[Japanese invasion of French Indochina]] in September 1940 came great concerns about the possible Japanese invasion of the Dutch Indies to secure their oil. After the U.S. banned all exports of steel and iron scrap, the next day Japan signed the [[Tripartite Pact]] and this led Washington to fear that a complete U.S. oil embargo would prompt the Japanese to invade the Dutch East Indies. On June 16, 1941 Harold Ickes, who was appointed Petroleum Coordinator for National Defense, stopped a shipment of oil from Philadelphia to Japan in light of the oil shortage on the East coast due to increased exports to Allies. He also telegrammed all oil suppliers on the East coast not to ship any oil to Japan without his permission. President Roosevelt countermanded Ickes' orders telling Ickes that the ". . . I simply have not got enough Navy to go around and every little episode in the Pacific means fewer ships in the Atlantic". <ref>Daniel Yergin, The Prize, Simon & Schuster, 1992, p.316-317</ref> On July 25, 1941 the U.S. froze all Japanese financial assets and licenses would be required for each use of the frozen funds including oil purchases that could produce aviation gasoline. On July 28, 1941 Japan invaded southern Indochina. The debate inside the Japanese government as to its oil and gasoline situation was leading to invasion of the Dutch East Indies but this would mean war with the U.S. whose Pacific fleet was a threat to their flank. This situation led to the decision to attack the U.S. fleet at Pearl Harbor before proceeding with the Dutch East Indies invasion. On December 7, 1941 Japan attacked Pearl Harbor and the next day the Netherlands declared war on Japan which initiated the [[Dutch East Indies campaign]]. ===United States=== Early in 1944, William Boyd, president of the American Petroleum Institute and chairman of the Petroleum Industry War Council said: "The Allies may have floated to victory on a wave of oil in World War I, but in this infinitely greater World War II, we are flying to victory on the wings of petroleum". In December, 1941 the United States had 385,000 oil wells producing 1.4 billion barrels of oil a year and 100-octane aviation gasoline capacity was at 40,000 barrels a day. By 1944 the U.S. was producing over 1.5 billion barrels a year (67 percent of world production) and the petroleum industry had built 122 new plants for the production of 100-octane aviation gasoline and capacity was over 400,000 barrels a day - an increase of more than ten-fold. It was estimated that the U.S. was producing enough 100-octane aviation gasoline to permit the dropping of 20,000 tons of bombs on the enemy every day of the year. The record of gasoline consumption by the Army prior to June, 1943 was uncoordinated as each supply service of the Army purchased its own petroleum products and no centralized system of control nor records existed. On June 1, 1943 the Army created the Fuels and Lubricants Division of the Quartermaster Corps and from their records they tabulated that the Army (excluding fuels and lubricants for aircraft) purchased over 2.4 billion gallons of gasoline for delivery to overseas theaters between June 1, 1943 through August, 1945. That figure does not include gasoline used by the Army inside the United States.<ref>Erna Risch and Chester L. Kieffer, United States Army in World War II, The Technical Services, The Quartermaster Corps: Organization, Supply, and Services, Office of the CHief of Military History, Department of the Army, Washington, D.C., 1955, p. 128-129</ref> Motor fuel production had declined from 701,000,000 barrels in 1941 down to 608,000,000 barrels in 1943.<ref>Robert E. Allen, Director of Information, American Petroleum Institute, The American Year Book - 1946, Thomas Nelson & Sons, copyright 1947, p.499</ref> World War II marked the first time in U.S. history that gasoline was rationed and the government imposed price controls to prevent inflation. Gasoline consumption per automobile declined from 755 gallons per year in 1941 down to 540 gallons in 1943 with the goal of preserving rubber for tires since the Japanese had cut the U.S. off from over 90 percent of its rubber supply from the Dutch East Indies and the U.S. synthetic rubber industry was in its infancy. Average gasoline prices went from an all-time record low of $0.1275 per gallon ($0.1841 with taxes) in 1940 to $0.1448 per gallon ($0.2050 with taxes) in 1945.<ref>Robert E. Allen, Director of Information, American Petroleum Institute, The American Year Book - 1946, Thomas Nelson & Sons, copyright 1947, p.512-518</ref> Even with the world's largest gasoline production, the U.S. military still found that more was needed. When the Allied breakout after D-Day found their armies stretching their supply lines to a dangerous point, the make-shift solution was the [[Red Ball Express]]. But even this soon was inadequate. The trucks in the convoys had to drive longer distances as the armies advanced and they were consuming a greater percentage of the same gasoline they were trying to deliver. In 1944, General George Patton's Third Army finally stalled just short of the German border after running out of gasoline. The general was so upset at the arrival of a truckload of rations instead of gasoline he was reported to have shouted: "Hell, they send us food, when they know we can fight without food but not without oil."<ref>Robert E. Allen, Director of Information, American Petroleum Institute, The American Year Book - 1946, Thomas Nelson & Sons, copyright 1947, p.498</ref> The solution had to wait for the repairing of the railroad lines and bridges so that the more efficient trains could replace the gasoline consuming truck convoys. ===United States, 1946 to present=== In the 1950s oil refineries started to focus on high octane fuels, and then detergents were added to gasoline to clean the jets in carburetors. The 1970s witnessed greater attention to the environmental consequences of burning gasoline. These considerations led to the phasing out of TEL and its replacement by other antiknock compounds. Subsequently, low-sulfur gasoline was introduced, in part to preserve the catalysts in modern exhaust systems.<ref name=Ullmann/> ==Chemical analysis and production== [[File:GasolineComp.png|thumb|upright=1.35|right|Some of the main components of gasoline: [[isooctane]], [[butane]], 3-[[ethyltoluene]], and the octane enhancer [[MTBE]]]] [[File:Nodding donkey.jpg|thumb|A [[pumpjack]] in the United States]] [[File:Gulf Offshore Platform.jpg|thumb|An oil rig in the [[Gulf of Mexico]]]] Gasoline is produced in [[oil refinery|oil refineries]]. Roughly {{convert|19|gal|liter}} of gasoline is derived from a {{convert|42|gal|liter|adj=on}} barrel of [[crude oil]].<ref>{{cite web|url=https://www.eia.gov/energyexplained/index.cfm?page=gasoline_home|title=Gasoline—a petroleum product|author=<!--Not stated-->|date=12 August 2016|website=U.S Energy Information Administration website|publisher=U.S Energy Information Administration|access-date=15 May 2017|deadurl=no|archiveurl=https://web.archive.org/web/20170524145355/https://www.eia.gov/Energyexplained/index.cfm?page=gasoline_home|archivedate=24 May 2017|df=dmy-all}}</ref> Material separated from crude oil via [[distillation]], called virgin or straight-run gasoline, does not meet specifications for modern engines (particularly the [[octane rating]]; see below), but can be pooled to the gasoline blend. The bulk of a typical gasoline consists of a homogeneous mixture of small, relatively lightweight [[hydrocarbon]]s with between 4 and 12 [[carbon]] atoms per molecule (commonly referred to as C4–C12).<ref name=Ullmann>Werner Dabelstein, Arno Reglitzky, Andrea Schütze and Klaus Reders "Automotive Fuels" in Ullmann's Encyclopedia of Industrial Chemistry 2007, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a16_719.pub2}}</ref> It is a mixture of paraffins ([[alkane]]s), olefins ([[alkene]]s) and [[cycloalkane]]s (naphthenes). The usage of the terms ''paraffin'' and ''olefin'' in place of the standard chemical nomenclature ''alkane'' and ''alkene'', respectively, is particular to the oil industry. The actual ratio of molecules in any gasoline depends upon: *the oil refinery that makes the gasoline, as not all refineries have the same set of processing units; *the [[crude oil]] feed used by the refinery; *the grade of gasoline (in particular, the octane rating). The various refinery streams blended to make gasoline have different characteristics. Some important streams include: *'''straight-run gasoline''', commonly referred to as ''naphtha'', which is distilled directly from crude oil. Once the leading source of fuel, its low octane rating required lead additives. It is low in aromatics (depending on the grade of the crude oil stream) and contains some cycloalkanes (naphthenes) and no olefins (alkenes). Between 0 and 20 percent of this stream is pooled into the finished gasoline, because the supply of this fraction is insufficient{{clarify|date=January 2015}} and its [[Octane rating#Research Octane Number (RON)|RON]] is too low.{{citation needed|date=September 2014}} The chemical properties (namely RON and [[Reid vapor pressure]]) of the straight-run gasoline can be improved through [[Catalytic reforming|reforming]] and [[isomerisation]]. However, before feeding those units, the naphtha needs to be split into light and heavy naphtha. Straight-run gasoline can be also used as a feedstock into steam-crackers to produce olefins. *'''reformate''', produced in a [[catalytic reformer]], has a high octane rating with high aromatic content and relatively low olefin content. Most of the [[benzene]], [[toluene]] and [[xylene]] (the so-called [[BTX (chemistry)|BTX]] hydrocarbons) are more valuable as chemical feedstocks and are thus removed to some extent. *'''catalytic cracked gasoline''', or catalytic cracked [[petroleum naphtha|naphtha]], produced with a [[Fluid catalytic cracking|catalytic cracker]], has a moderate octane rating, high olefin content and moderate aromatic content. *'''hydrocrackate''' (heavy, mid and light), produced with a [[hydrocracker]], has a medium to low octane rating and moderate aromatic levels. *'''alkylate''' is produced in an [[alkylation]] unit, using [[isobutane]] and olefins as feedstocks. Finished alkylate contains no aromatics or olefins and has a high MON. *'''isomerate''' is obtained by isomerizing low-octane straight-run gasoline into iso-paraffins (non-chain alkanes, such as [[isooctane]]). Isomerate has a medium RON and MON, but no aromatics or olefins. *'''butane''' is usually blended in the gasoline pool, although the quantity of this stream is limited by the RVP specification. The terms above are the jargon used in the oil industry and terminology varies. Currently, many countries set limits on gasoline [[aromatic]]s in general, benzene in particular, and olefin (alkene) content. Such regulations have led to an increasing preference for high-octane pure paraffin (alkane) components, such as alkylate, and are forcing refineries to add processing units to reduce benzene content. In the European Union, the benzene limit is set at 1% volume for all grades of automotive gasoline. Gasoline can also contain other [[organic compound]]s, such as [[organic ether]]s (deliberately added), plus small levels of contaminants, in particular [[organosulfur]] compounds (which is usually removed at the refinery). ==Physical properties== ===Density=== The [[density]] of gasoline generally ranges between 0.71 and 0.77&nbsp;kg/L ({{nowrap|719.7 [[kg]]/[[Cubic meter|m³]]}}; 0.026 [[Pound (mass)|lb]]/[[cubic inch|in³]]; 6.073&nbsp;lb/[[US liquid gallon|US gal]]; 7.29&nbsp;lb/[[imperial gallon|imp gal]]), with higher densities having a greater volume of aromatics.<ref>{{cite web|title=Lead-Free gasoline Material Safety Data Sheet |author=Bell Fuels |publisher=[[NOAA]] |url=http://www.sefsc.noaa.gov/HTMLdocs/Gasoline.htm |archive-url=https://web.archive.org/web/20020820074636/http://www.sefsc.noaa.gov/HTMLdocs/Gasoline.htm |dead-url=yes |archive-date=20 August 2002 |accessdate=6 July 2008 |df= }}</ref> Finished marketable gasoline is traded with a standard reference of 0.755&nbsp;kg/L, and its price is escalated or de-escalated according to its actual density. Because of its low density, gasoline floats on water, and so water cannot generally be used to extinguish a gasoline fire unless applied in a fine mist. ===Stability=== Quality gasoline should be stable for six months if stored properly, but as gasoline is a mixture rather than a single compound, it will break down slowly over time due to the separation of the components. Gasoline stored for a year will most likely be able to be burned in an internal combustion engine without too much trouble but the effects of long-term storage will become more noticeable with each passing month until a time comes when the gasoline should be diluted with ever-increasing amounts of freshly made fuel so that the older gasoline may be used up. If left undiluted, improper operation will occur and this may include engine damage from misfiring or the lack of proper action of the fuel within a [[fuel injection]] system and from an onboard computer attempting to compensate (if applicable to the vehicle). Gasoline should ideally be stored in an airtight container (to prevent [[oxidation]] or water vapor mixing in with the gas) that can withstand the [[vapor pressure]] of the gasoline without venting (to prevent the loss of the more volatile fractions) at a stable cool temperature (to reduce the excess pressure from liquid expansion and to reduce the rate of any decomposition reactions). When gasoline is not stored correctly, gums and solids may result, which can corrode system components and accumulate on wetted surfaces, resulting in a condition called "stale fuel". Gasoline containing ethanol is especially subject to absorbing atmospheric moisture, then forming gums, solids or two phases (a hydrocarbon phase floating on top of a water-alcohol phase). The presence of these degradation products in the fuel tank or fuel lines plus a carburetor or fuel injection components makes it harder to start the engine or causes reduced engine performance. On resumption of regular engine use, the buildup may or may not be eventually cleaned out by the flow of fresh gasoline. The addition of a fuel stabilizer to gasoline can extend the life of fuel that is not or cannot be stored properly, though removal of all fuel from a fuel system is the only real solution to the problem of long-term storage of an engine or a machine or vehicle. Typical fuel stabilizers are proprietary mixtures containing [[mineral spirits]], [[isopropyl alcohol]], [[1,2,4-trimethylbenzene]] or [[gasoline additive|other additives]]. Fuel stabilizers are commonly used for small engines, such as lawnmower and tractor engines, especially when their use is sporadic or seasonal (little to no use for one or more seasons of the year). Users have been advised to keep gasoline containers more than half full and properly capped to reduce air exposure, to avoid storage at high temperatures, to run an engine for ten minutes to circulate the stabilizer through all components prior to storage, and to run the engine at intervals to purge stale fuel from the carburetor.<ref name=Ullmann/> Gasoline stability requirements are set by the standard [[ASTM International|ASTM]] D4814. This standard describes the various characteristics and requirements of automotive fuels for use over a wide range of operating conditions in ground vehicles equipped with spark-ignition engines. ===Energy content=== A gasoline-fueled internal combustion engine obtains energy from the combustion of gasoline's various hydrocarbons with oxygen from the ambient air, yielding [[carbon dioxide]] and [[water]] as exhaust. The combustion of octane, a representative species, performs the chemical reaction: <chem>2 C8H18 + 25 O2 -> 16 CO2 + 18 H2O </chem> Gasoline contains about 46.7 [[megajoule|MJ]]/kg (127 MJ/US gal; 35.3 [[kilowatt hour|kWh]]/US gal; 13.0 kWh/kg; 120,405 [[British thermal unit|BTU]]/US gal), quoting the lower heating value.<ref>{{cite web|url=http://www.eia.gov/Energyexplained/?page=about_energy_units|title=Energy Information Administration|website=www.eia.gov|deadurl=no|archiveurl=https://web.archive.org/web/20151215012732/http://www.eia.gov/Energyexplained/?page=about_energy_units|archivedate=15 December 2015|df=dmy-all}}</ref> Gasoline blends differ, and therefore actual energy content varies according to the season and producer by up to 1.75% more or less than the average.<ref>{{cite web|url=http://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf|title=Fuel Properties Comparison|last=|first=|date=|website=Alternative Fuels Data Center|publisher=|access-date=31 October 2016|deadurl=no|archiveurl=https://web.archive.org/web/20161031034323/http://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf|archivedate=31 October 2016|df=dmy-all}}</ref> On average, about 74 L (19.5 US gal; 16.3 imp gal) of gasoline are available from a barrel of crude oil (about 46% by volume), varying with the quality of the crude and the grade of the gasoline. The remainder are products ranging from tar to [[naphtha]].<ref>{{cite web |url = http://www.gravmag.com/oil.html |title = Oil Industry Statistics from Gibson Consulting |accessdate = 31 July 2008 |deadurl = no |archiveurl = https://web.archive.org/web/20080912232920/http://www.gravmag.com/oil.html |archivedate = 12 September 2008 |df = dmy-all }}</ref> A high-octane-rated fuel, such as [[liquefied petroleum gas]] (LPG), has an overall lower power output at the typical 10:1 [[compression ratio]] of an engine design optimized for gasoline fuel. An engine [[engine tuning|tuned]] for [[Autogas|LPG]] fuel via higher compression ratios (typically 12:1) improves the power output. This is because higher-octane fuels allow for a higher compression ratio without knocking, resulting in a higher cylinder temperature, which improves efficiency. Also, increased mechanical efficiency is created by a higher compression ratio through the concomitant higher expansion ratio on the power stroke, which is by far the greater effect. The higher expansion ratio extracts more work from the high-pressure gas created by the combustion process. An [[Atkinson cycle]] engine uses the timing of the valve events to produce the benefits of a high expansion ratio without the disadvantages, chiefly detonation, of a high compression ratio. A high expansion ratio is also one of the two key reasons for the efficiency of [[diesel engine]]s, along with the elimination of pumping losses due to throttling of the intake air flow. The lower energy content of LPG by liquid volume in comparison to gasoline is due mainly to its lower density. This lower density is a property of the lower [[molecular weight]] of [[propane]] (LPG's chief component) compared to gasoline's blend of various hydrocarbon compounds with heavier molecular weights than propane. Conversely, LPG's energy content by weight is higher than gasoline's due to a higher [[hydrogen]]-to-[[carbon]] ratio. Molecular weights of the representative octane combustion are C₈H₁₈ 114, O₂ 32, CO₂ 44, H₂O 18; therefore 1&nbsp;kg of fuel reacts with 3.51&nbsp;kg of oxygen to produce 3.09&nbsp;kg of carbon dioxide and 1.42&nbsp;kg of water. ==Octane rating== {{main|Octane rating}} [[Spark-ignition engine]]s are designed to burn gasoline in a controlled process called [[deflagration]]. However, the unburned mixture may autoignite by pressure and heat alone, rather than igniting from the [[spark plug]] at exactly the right time, causing a rapid pressure rise which can damage the engine. This is often referred to as [[engine knocking]] or end-gas knock. Knocking can be reduced by increasing the gasoline's resistance to [[autoignition temperature|autoignition]], which is expressed by its octane rating. Octane rating is measured relative to a mixture of [[2,2,4-Trimethylpentane|2,2,4-trimethylpentane]] (an [[isomer]] of [[octane]]) and n-[[heptane]]. There are different conventions for expressing octane ratings, so the same physical fuel may have several different octane ratings based on the measure used. One of the best known is the research octane number (RON). The octane rating of typical commercially available gasoline varies by country. In [[Finland]], [[Sweden]] and [[Norway]], 95 RON is the standard for regular unleaded gasoline and 98 RON is also available as a more expensive option. In the United Kingdom, ordinary regular unleaded gasoline is sold at 95 RON (commonly available), premium unleaded gasoline is always 97 RON, and super-unleaded is usually 97–98 RON.{{Citation needed|date=September 2014}} However, both Shell and BP produce fuel at 102 RON for cars with high-performance engines, and in 2006 the supermarket chain [[Tesco]] began to sell super-unleaded gasoline rated at 99 RON. In the United States, octane ratings in unleaded fuels vary between 85<ref>{{cite web|url=http://rapidcityjournal.com/news/local/octane-warning-labels-not-posted-at-many-gas-stations/article_681e07bc-3cd3-5e0c-a3c7-c06fcc4d319c.html|title=85-octane warning labels not posted at many gas stations|author=Ryan Lengerich Journal staff|work=Rapid City Journal|deadurl=no|archiveurl=https://web.archive.org/web/20150615025518/http://rapidcityjournal.com/news/local/octane-warning-labels-not-posted-at-many-gas-stations/article_681e07bc-3cd3-5e0c-a3c7-c06fcc4d319c.html|archivedate=15 June 2015|df=dmy-all}}</ref> and 87 AKI (91–92 RON) for regular, 89–90 AKI (94–95 RON) for mid-grade (equivalent to European regular), up to 90–94 AKI (95–99 RON) for premium (European premium). As South Africa's largest city, [[Johannesburg]], is located on the [[Highveld]] at {{convert|1753|m|ft}} above sea level, the [[Automobile Association of South Africa]] recommends 95-octane gasoline at low altitude and 93-octane for use in Johannesburg because "The higher the altitude the lower the air pressure, and the lower the need for a high octane fuel as there is no real performance gain".<ref>{{cite web |url=http://www.aa.co.za/about/press-room/press-releases/9593-what-is-the-difference-reallyij.html |title=95/93 – What is the Difference, Really? |publisher=Automobile Association of South Africa (AA) |accessdate=26 January 2017 |deadurl=yes |archiveurl=https://web.archive.org/web/20161229112643/https://www.aa.co.za/about/press-room/press-releases/9593-what-is-the-difference-reallyij.html |archivedate=29 December 2016 |df=dmy-all }}</ref> Octane rating became important as the military sought higher output for [[aircraft engine]]s in the late 1930s and the 1940s. A higher octane rating allows a higher [[compression ratio]] or [[supercharger]] boost, and thus higher temperatures and pressures, which translate to higher power output. Some scientists{{who|date=August 2018}} even predicted that a nation with a good supply of high-octane gasoline would have the advantage in air power. In 1943, the [[Rolls-Royce Merlin]] aero engine produced 1,320 horsepower (984&nbsp;kW) using 100 RON fuel from a modest 27-liter displacement. By the time of [[Operation Overlord]], both the RAF and USAAF were conducting some operations in Europe using 150 RON fuel (100/150 [[avgas]]), obtained by adding 2.5% [[aniline]] to 100-octane avgas.<ref name="Magazines1936">{{cite book|author=Hearst Magazines|title=Popular Mechanics|url=https://books.google.com/books?id=lNsDAAAAMBAJ&pg=PA524|date=April 1936|publisher=Hearst Magazines|pages=524–|issn=0032-4558|deadurl=no|archiveurl=https://web.archive.org/web/20130619054026/http://books.google.com/books?id=lNsDAAAAMBAJ&pg=PA524|archivedate=19 June 2013|df=dmy-all}}</ref> By this time the Rolls-Royce Merlin 66 was developing 2,000&nbsp;hp using this fuel. ==Additives== {{See also|List of gasoline additives}} ===Antiknock additives=== [[File:Reservekanister.JPG|thumb|left|upright=1.15|A plastic container for storing gasoline used in Germany]] Almost all countries in the world have phased out automotive leaded fuel. In 2011, six countries<ref>{{cite web|url=http://www.lead.org.au/lanv11n4/lanv11n4-5.html|title=List of countries using leaded petrol in 2011|deadurl=no|archiveurl=https://web.archive.org/web/20140629223457/http://www.lead.org.au/lanv11n4/lanv11n4-5.html|archivedate=29 June 2014|df=dmy-all}}</ref> were still using leaded gasoline: [[Afghanistan]], [[Myanmar]], [[North Korea]], [[Algeria]], [[Iraq]] and [[Yemen]]. It was expected that by the end of 2013 those countries, too, would ban leaded gasoline,<ref>{{cite web|url=https://news.yahoo.com/un-leaded-fuel-gone-2013-223737108.html|title=UN: Leaded fuel to be gone by 2013|deadurl=yes|archiveurl=https://web.archive.org/web/20160305062416/http://news.yahoo.com/un-leaded-fuel-gone-2013-223737108.html|archivedate=5 March 2016|df=dmy-all}}</ref> but this target was not met. Algeria replaced leaded with unleaded automotive fuel only in 2015.{{citation needed|date=August 2018}} Different additives have replaced the lead compounds. The most popular additives include [[aromatic hydrocarbon]]s, [[ether]]s and [[alcohol as a fuel|alcohol]] (usually [[ethanol]] or [[methanol]]). For technical reasons, the use of leaded additives is still permitted worldwide for the formulation of some grades of [[aviation gasoline]] such as [[100LL]], because the required octane rating would be technically infeasible to reach without the use of leaded additives. [[File:GasCan.jpg|thumb|A gas can]] ====Tetraethyllead==== {{main|Tetraethyllead}} <!-- This section is linked from [[Lead]] --> Gasoline, when used in high-[[compression (physical)|compression]] internal combustion engines, tends to autoignite or "detonate" causing damaging [[engine knocking]] (also called "pinging" or "pinking"). To address this problem, [[tetraethyllead]] (TEL) was widely adopted as an additive for gasoline in the 1920s. With the discovery of the seriousness of the extent of environmental and health damage caused by lead compounds, however, and the incompatibility of lead with [[catalytic converter]]s, leaded gasoline was phased out in the United States beginning in 1973. By 1995, leaded fuel accounted for only 0.6 percent of total gasoline sales and under 2000 [[short tons]] (1814 t) of lead per year. From 1 January 1996, the [[Clean Air Act (United States)|U.S. Clean Air Act]] banned the sale of leaded fuel for use in on-road vehicles in the U.S. The use of TEL also necessitated other additives, such as [[dibromoethane]]. European countries began replacing lead-containing additives by the end of the 1980s, and by the end of the 1990s, leaded gasoline was banned within the entire European Union. Reduction in the average lead content of human blood is believed to be a major cause for falling violent crime rates around the world, including in the United States<ref name="WashingtonPostCrime">{{cite news | url=https://www.washingtonpost.com/blogs/wonkblog/wp/2013/04/22/lead-abatement-alcohol-taxes-and-10-other-ways-to-reduce-the-crime-rate-without-annoying-the-nra/ | title=Lead abatement, alcohol taxes and 10 other ways to reduce the crime rate without annoying the NRA | work=Washington Post | date=22 April 2013 | accessdate=23 May 2013 | author=Matthews, Dylan | deadurl=no | archiveurl=https://web.archive.org/web/20130512052321/http://www.washingtonpost.com/blogs/wonkblog/wp/2013/04/22/lead-abatement-alcohol-taxes-and-10-other-ways-to-reduce-the-crime-rate-without-annoying-the-nra/ | archivedate=12 May 2013 | df=dmy-all }}</ref> and South Africa.<ref name="BusinessDayCrime">{{cite web | url=http://www.bdlive.co.za/opinion/columnists/2013/01/22/ban-on-lead-may-yet-give-us-respite-from-crime | title=Ban on lead may yet give us respite from crime | publisher=Business Day | date=22 January 2013 | accessdate=23 May 2013 | author=Marrs, Dave | deadurl=bot: unknown | archiveurl=https://web.archive.org/web/20130406072130/http://www.bdlive.co.za/opinion/columnists/2013/01/22/ban-on-lead-may-yet-give-us-respite-from-crime | archivedate=6 April 2013 | df=dmy-all }}</ref> A statistically significant correlation has been found between the usage rate of leaded gasoline and violent crime: taking into account a 22-year time lag, the violent crime curve virtually tracks the lead exposure curve.<ref name="Reyes">Reyes, J. W. (2007). [http://www.amherst.edu/~jwreyes/papers/LeadCrimeNBERWP13097.pdf "The Impact of Childhood Lead Exposure on Crime". National Bureau of Economic Research.] {{webarchive|url=https://web.archive.org/web/20070929131323/http://www.amherst.edu/~jwreyes/papers/LeadCrimeNBERWP13097.pdf |date=29 September 2007 }} "a" ref citing Pirkle, Brody, et. al (1994). Retrieved 17 August 2009.</ref><ref>{{cite news|url=https://www.independent.co.uk/environment/green-living/ban-on-leaded-petrol-has-cut-crime-rates-around-the-world-398151.html|title=Ban on leaded petrol 'has cut crime rates around the world'|date=28 October 2007|publisher=|deadurl=no|archiveurl=https://web.archive.org/web/20170829032830/https://www.independent.co.uk/environment/green-living/ban-on-leaded-petrol-has-cut-crime-rates-around-the-world-398151.html|archivedate=29 August 2017|df=dmy-all}}</ref> ====Lead replacement petrol (gasoline)==== Lead replacement petrol (LRP) was developed for vehicles designed to run on leaded fuels and incompatible with unleaded fuels. Rather than tetraethyllead it contains other metals such as [[potassium]] compounds or [[methylcyclopentadienyl manganese tricarbonyl]] (MMT); these are purported to buffer soft exhaust valves and seats so that they do not suffer recession due to the use of unleaded fuel. LRP was marketed during and after the phaseout of leaded motor fuels in the [[United Kingdom]], [[Australia]], [[South Africa]] and some other countries.{{vague|date=August 2016}} Consumer confusion led to a widespread mistaken preference for LRP rather than unleaded,<ref>{{cite news |last=Seggie |first=Eleanor |date=5 August 2011 |title=More than 20% of SA cars still using lead-replacement petrol but only 1% need it |url=http://www.engineeringnews.co.za/article/cleaner-fuels-for-sa-2011-08-05 |work=[[Engineering News (Creamer Media)|Engineering News]] |location=South Africa |access-date=30 March 2017 |deadurl=no |archiveurl=https://web.archive.org/web/20161013195145/http://www.engineeringnews.co.za/article/cleaner-fuels-for-sa-2011-08-05 |archivedate=13 October 2016 |df=dmy-all }}</ref> and LRP was phased out 8 to 10 years after the introduction of unleaded.<ref>{{cite news |first1=Andrew |last1=Clark |date=14 August 2002 |title=Petrol for older cars about to disappear |url=https://www.theguardian.com/uk/2002/aug/15/oil.business |work=[[The Guardian]] |location=London |access-date=30 March 2017 |deadurl=no |archiveurl=https://web.archive.org/web/20161229112618/https://www.theguardian.com/uk/2002/aug/15/oil.business |archivedate=29 December 2016 |df=dmy-all }}</ref> Leaded gasoline was withdrawn from sale in Britain after 31 December 1999, seven years after [[European Economic Community|EEC]] regulations signaled the end of production for cars using leaded gasoline in member states. At this stage, a large percentage of cars from the 1980s and early 1990s which ran on leaded gasoline were still in use, along with cars which could run on unleaded fuel. However, the declining number of such cars on British roads saw many gasoline stations withdrawing LRP from sale by 2003.<ref>{{Cite news |date=15 August 2002 |title=AA warns over lead replacement fuel |url=https://www.telegraph.co.uk/motoring/news/2717637/AA-warns-over-lead-replacement-fuel.html |work=[[The Daily Telegraph]] |location=London |access-date=30 March 2017 |deadurl=no |archiveurl=https://web.archive.org/web/20170421115246/http://www.telegraph.co.uk/motoring/news/2717637/AA-warns-over-lead-replacement-fuel.html |archivedate=21 April 2017 |df=dmy-all }}</ref> ====MMT==== [[Methylcyclopentadienyl manganese tricarbonyl]] (MMT) is used in Canada and Australia to boost octane rating.<ref>{{cite web|last1=Hollrah|first1=Don P.|last2=Burns|first2=Allen M.|title=MMT INCREASES OCTANE WHILE REDUCING EMISSIONS|url=http://www.ogj.com/articles/print/volume-89/issue-10/in-this-issue/refining/mmt-increases-octane-while-reducing-emissions.html|website=www.ogj.com|deadurl=no|archiveurl=https://web.archive.org/web/20161117072536/http://www.ogj.com/articles/print/volume-89/issue-10/in-this-issue/refining/mmt-increases-octane-while-reducing-emissions.html|archivedate=17 November 2016|df=dmy-all}}</ref> It also helps old cars designed for leaded fuel run on unleaded fuel without the need for additives to prevent valve problems.{{Citation needed|date=August 2016}} Its use in the United States has been restricted by regulations.<ref>{{cite web|last1=EPA, OAR, OTAQ|first1=US|title=EPA Comments on the Gasoline Additive MMT|url=https://www.epa.gov/gasoline-standards/epa-comments-gasoline-additive-mmt|website=www.epa.gov|language=en|deadurl=no|archiveurl=https://web.archive.org/web/20161117070650/https://www.epa.gov/gasoline-standards/epa-comments-gasoline-additive-mmt|archivedate=17 November 2016|df=dmy-all}}</ref> Its use in the European Union is restricted by Article 8a of the Fuel Quality Directive<ref>http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:140:0088:0113:EN:PDF</ref> following its testing under the Protocol for the evaluation of effects of metallic fuel-additives on the emissions performance of vehicles.<ref>{{cite web|url=http://ec.europa.eu/clima/policies/transport/fuel/docs/fuel_metallic_additive_protocol_en.pdf |title=Archived copy |accessdate=30 August 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20161008030628/http://ec.europa.eu/clima/policies/transport/fuel/docs/fuel_metallic_additive_protocol_en.pdf |archivedate=8 October 2016 |df= }}</ref> ===Fuel stabilizers (antioxidants and metal deactivators)=== [[File:Antioxidant.png|thumb|upright=1.15|Substituted [[phenol]]s and derivatives of [[phenylenediamine]] are common antioxidants used to inhibit gum formation in gasoline]] Gummy, sticky resin deposits result from [[oxidation|oxidative]] degradation of gasoline during long-term storage. These harmful deposits arise from the oxidation of [[alkene]]s and other minor components in gasoline (see [[drying oil]]s). Improvements in refinery techniques have generally reduced the susceptibility of gasolines to these problems. Previously, catalytically or thermally cracked gasolines were most susceptible to oxidation. The formation of gums is accelerated by copper salts, which can be neutralized by additives called [[metal deactivator]]s. This degradation can be prevented through the addition of 5–100 ppm of [[antioxidant]]s, such as [[phenylenediamine]]s and other [[amine]]s.<ref name=Ullmann/> Hydrocarbons with a [[bromine number]] of 10 or above can be protected with the combination of unhindered or partially hindered [[phenol]]s and oil-soluble strong amine bases, such as hindered phenols. "Stale" gasoline can be detected by a [[colorimetric]] [[enzymatic]] test for [[organic peroxide]]s produced by oxidation of the gasoline.<ref>{{patent|AU|2000/72399 A1|Gasoline test kit}}</ref><!---See http://www.patentlens.net/patentlens/structured.cgi?patnum=AU_2000/72399_A1#show if template link fails---> Gasolines are also treated with [[metal deactivator]]s, which are compounds that sequester (deactivate) metal salts that otherwise accelerate the formation of gummy residues. The metal impurities might arise from the engine itself or as contaminants in the fuel. ===Detergents=== Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve [[combustion]] and allow easier starting in cold climates. High levels of detergent can be found in [[Top Tier Detergent Gasoline]]s. The specification for Top Tier Detergent Gasolines was developed by four automakers: [[General Motors|GM]], [[Honda]], [[Toyota]] and [[BMW]]. According to the bulletin, the minimal U.S. [[Environmental Protection Agency|EPA]] requirement is not sufficient to keep engines clean.<ref>"Top Tier Detergent Gasoline (Deposits, Fuel Economy, No Start, Power, Performance, Stall Concerns)", GM Bulletin, 04-06-04-047, 06-Engine/Propulsion System, June 2004</ref> Typical detergents include [[Amine#Classification of amines|alkylamines]] and [[alkyl phosphate]]s at the level of 50–100 ppm.<ref name=Ullmann/> ===Ethanol=== {{see also|Ethanol fuel|Common ethanol fuel mixtures}} ====European Union==== In the EU, 5% [[ethanol]] can be added within the common gasoline spec (EN 228). Discussions are ongoing to allow 10% blending of ethanol (available in Finnish, French and German gas stations). In Finland, most gasoline stations sell 95E10, which is 10% ethanol, and 98E5, which is 5% ethanol. Most gasoline sold in Sweden has 5–15% ethanol added. Three different ethanol blends are sold in the Netherlands—E5, E10 and hE15. The last of these differs from standard ethanol–gasoline blends in that it consists of 15% [[hydrous ethanol]] (i.e., the ethanol–water [[azeotrope]]) instead of the anhydrous ethanol traditionally used for blending with gasoline. ====Brazil==== The [[Brazilian National Agency of Petroleum, Natural Gas and Biofuels]] (ANP) requires gasoline for automobile use to have 27.5% of ethanol added to its composition.<ref>{{cite web|url=http://www.senado.gov.br/atividade/materia/detalhes.asp?p_cod_mate=100053|title=MEDIDA PROVISÓRIA nº 532, de 2011|work=senado.gov.br|deadurl=no|archiveurl=https://web.archive.org/web/20110919030421/http://www.senado.gov.br/atividade/materia/detalhes.asp?p_cod_mate=100053|archivedate=19 September 2011|df=dmy-all}}</ref> Pure hydrated ethanol is also available as a fuel. ====Australia==== Legislation requires retailers to label fuels containing ethanol on the dispenser, and limits ethanol use to 10% of gasoline in Australia. Such gasoline is commonly called [[Common ethanol fuel mixtures|E10]] by major brands, and it is cheaper than regular unleaded gasoline. ====United States==== The federal [[Renewable Fuel Standard]] (RFS) effectively requires refiners and blenders to blend renewable [[biofuel]]s (mostly ethanol) with gasoline, sufficient to meet a growing annual target of total gallons blended. Although the mandate does not require a specific percentage of ethanol, annual increases in the target combined with declining [[gasoline consumption]] has caused the typical ethanol content in gasoline to approach 10%. Most fuel pumps display a sticker that states that the fuel may contain up to 10% ethanol, an intentional disparity that reflects the varying actual percentage. Until late 2010, fuel retailers were only authorized to sell fuel containing up to 10 percent ethanol (E10), and most vehicle warranties (except for flexible fuel vehicles) authorize fuels that contain no more than 10 percent ethanol.{{citation needed|date=October 2016}} In parts of the United States, ethanol is sometimes added to gasoline without an indication that it is a component. ====India==== In October 2007, the [[Government of India]] decided to make 5% ethanol blending (with gasoline) mandatory. Currently, 10% ethanol blended product (E10) is being sold in various parts of the country.<ref name="Government to take a call on ethanol price soon">{{cite news | url=http://www.thehindu.com/news/national/article2647940.ece | title=Government to take a call on ethanol price soon | date=21 November 2011 | accessdate=25 May 2012 | location=Chennai, India | work=The Hindu | deadurl=no | archiveurl=https://web.archive.org/web/20120505123807/http://www.thehindu.com/news/national/article2647940.ece | archivedate=5 May 2012 | df=dmy-all }}</ref><ref name="India to raise ethanol blending in gasoline to 10%">{{cite news | url=http://www.commodityonline.com/news/india-to-raise-ethanol-blending-in-gasoline-to-10-43892-3-43893.html | title=India to raise ethanol blending in gasoline to 10% | date=22 November 2011 | accessdate=25 May 2012 | deadurl=no | archiveurl=https://web.archive.org/web/20140407231713/http://www.commodityonline.com/news/india-to-raise-ethanol-blending-in-gasoline-to-10-43892-3-43893.html | archivedate=7 April 2014 | df=dmy-all }}</ref> Ethanol has been found in at least one study to damage catalytic converters.<ref>{{cite web |url=http://european-biogas.eu/wp-content/uploads/2014/02/022013_Fuel-impact-on-the-aging-of-TWC%E2%80%99s-under-real-driving-conditions_Winkler-et-al.pdf |title=Archived copy |accessdate=2016-03-16 |deadurl=no |archiveurl=https://web.archive.org/web/20160324165803/http://european-biogas.eu/wp-content/uploads/2014/02/022013_Fuel-impact-on-the-aging-of-TWC%E2%80%99s-under-real-driving-conditions_Winkler-et-al.pdf |archivedate=24 March 2016 |df=dmy-all }}</ref> ===Dyes=== {{Main|Fuel dyes}} Though gasoline is a naturally colorless liquid, many gasolines are dyed in various colors to indicate their composition and acceptable uses. In Australia, the lowest grade of gasoline (RON 91) is dyed a light shade of red/orange and the medium grade (RON 95) is dyed yellow.<ref>{{cite web |url=http://www.aip.com.au/topics/mr_pdf/AIP_media_release_280912.pdf |title=Archived copy |accessdate=2012-11-22 |deadurl=yes |archiveurl=https://web.archive.org/web/20130409211243/http://www.aip.com.au/topics/mr_pdf/AIP_media_release_280912.pdf |archivedate=9 April 2013 |df=dmy-all }}</ref> In the United States, aviation gasoline ([[avgas]]) is dyed to identify its octane rating and to distinguish it from kerosene-based jet fuel, which is clear.<ref>{{cite web|url=http://www.eaa.org/autofuel/avgas/grades.asp |title=EAA - Avgas Grades |date=17 May 2008 |publisher= |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20080517022056/http://www.eaa.org/autofuel/avgas/grades.asp |archivedate=17 May 2008 |df= }}</ref> In Canada, the gasoline for marine and farm use is dyed red and is not subject to sales tax.<ref>{{cite web |url=https://umanitoba.ca/faculties/management/ti/media/docs/Fuel_Taxes_Road_Expenditures_1999.pdf |title=Archived copy |accessdate=2017-09-26 |deadurl=no |archiveurl=https://web.archive.org/web/20140410200621/http://umanitoba.ca/faculties/management/ti/media/docs/Fuel_Taxes_Road_Expenditures_1999.pdf |archivedate=10 April 2014 |df=dmy-all }} ''Fuel Taxes & Road Expenditures: Making the Link'', retrieved 2017 Sept 26, page 2</ref> ===Oxygenate blending=== [[Oxygenate]] blending adds [[oxygen]]-bearing compounds such as [[MTBE]], [[ETBE]], [[ethanol]] and [[biobutanol]]. The presence of these oxygenates reduces the amount of [[carbon monoxide]] and unburned fuel in the exhaust. In many areas throughout the U.S., oxygenate blending is mandated by EPA regulations to reduce smog and other airborne pollutants. For example, in Southern California, fuel must contain 2% oxygen by weight, resulting in a mixture of 5.6% ethanol in gasoline. The resulting fuel is often known as reformulated gasoline (RFG) or oxygenated gasoline, or in the case of California, [[California reformulated gasoline]]. The federal requirement that RFG contain oxygen was dropped on 6 May 2006 because the industry had developed [[Volatile organic compound|VOC]]-controlled RFG that did not need additional oxygen.<ref>{{cite web | url = http://www.epa.gov/otaq/rfg_regs.htm#usage | title = Removal of Reformulated Gasoline Oxygen Content Requirement (national) and Revision of Commingling Prohibition to Address Non-0xygenated Reformulated Gasoline (national) | date = 22 February 2006 | publisher = [[U.S. Environmental Protection Agency]] | deadurl = no | archiveurl = https://web.archive.org/web/20050920073346/http://www.epa.gov/otaq/rfg_regs.htm#usage | archivedate = 20 September 2005 | df = dmy-all }}</ref> MTBE was phased out in the U.S. due to groundwater contamination and the resulting regulations and lawsuits. Ethanol and, to a lesser extent, the ethanol-derived ETBE are common substitutes. A common ethanol-gasoline mix of 10% ethanol mixed with gasoline is called [[Ethanol fuel|gasohol]] or E10, and an ethanol-gasoline mix of 85% ethanol mixed with gasoline is called [[E85]]. The most extensive use of ethanol takes place in [[Brazil]], where the ethanol is derived from [[sugarcane]]. In 2004, over 3.4 billion US gallons (2.8&nbsp;billion imp&nbsp;gal; 13 million m³) of ethanol was produced in the United States for fuel use, mostly from [[maize|corn]], and E85 is slowly becoming available in much of the United States, though many of the relatively few stations vending E85 are not open to the general public.<ref>{{cite web | url = http://www.eere.energy.gov/afdc/fuels/stations_locator.html | title = Alternative Fueling Station Locator | publisher = [[U.S. Department of Energy]] | deadurl = yes | archiveurl = https://web.archive.org/web/20080714060953/http://www.eere.energy.gov/afdc/fuels/stations_locator.html | archivedate = 14 July 2008 | df = dmy-all | access-date = 14 July 2008 }}</ref> The use of [[bioethanol]], either directly or indirectly by conversion of such ethanol to bio-ETBE, is encouraged by the European Union [[Directive on the Promotion of the use of biofuels and other renewable fuels for transport]]. Since producing bioethanol from fermented sugars and starches involves [[distillation]], though, ordinary people in much of Europe cannot legally ferment and distill their own bioethanol at present (unlike in the U.S., where getting a [[BATF]] distillation permit has been easy since the [[1973 oil crisis]]). ==Safety== [[File:HAZMAT Class 3 Gasoline.png|thumb|HAZMAT class 3 gasoline]] ===Environmental considerations=== Combustion of {{convert|1|USgal|liter}} of gasoline produces {{convert|8.74|kg|lbs}} of carbon dioxide (2.3&nbsp;kg/l), a [[greenhouse gas]].<ref>{{cite web |url=http://www.slate.com/id/2152685/ |title=How Gasoline Becomes CO2 |publisher=Slate Magazine |date=1 November 2006 |deadurl=no |archiveurl=https://web.archive.org/web/20110820030124/http://www.slate.com/id/2152685/ |archivedate=20 August 2011 |df=dmy-all }}</ref><ref name="US Energy Information Administration">{{cite web|url=http://www.eia.gov/tools/faqs/faq.cfm?id=307&t=11|title=How much carbon dioxide is produced by burning gasoline and diesel fuel?|publisher=U.S. Energy Information Administration (EIA)|deadurl=no|archiveurl=https://web.archive.org/web/20131027195801/http://www.eia.gov/tools/faqs/faq.cfm?id=307&t=11|archivedate=27 October 2013|df=dmy-all}} {{PD-notice}}</ref> The main concern with gasoline on the environment, aside from the complications of its extraction and refining, is the [[climate change|effect on the climate]] through the production of carbon dioxide.<ref>https://www.un.org/en/sections/issues-depth/climate-change/index.html</ref> Unburnt gasoline and [[Automobile emissions control#Evaporative emissions control|evaporation from the tank]], when in the [[atmosphere]], reacts in [[sunlight]] to produce [[photochemical smog]]. Vapor pressure initially rises with some addition of ethanol to gasoline, but the increase is greatest at 10% by volume.{{Citation needed|reason=No source given for this claim|date=April 2016}} At higher concentrations of ethanol above 10%, the vapor pressure of the blend starts to decrease. At a 10% ethanol by volume, the rise in vapor pressure may potentially increase the problem of photochemical smog. This rise in vapor pressure could be mitigated by increasing or decreasing the percentage of ethanol in the gasoline mixture. The chief risks of such leaks come not from vehicles, but from gasoline delivery truck accidents and leaks from storage tanks. Because of this risk, most (underground) storage tanks now have extensive measures in place to detect and prevent any such leaks, such as monitoring systems (Veeder-Root, Franklin Fueling). Production of gasoline consumes 0.63 gallons of [[water]] per mile driven.<ref>{{cite web|url=http://www.circleofblue.org/waternews/wp-content/uploads/2010/08/Webber-water-in-transportation.pdf |title=Archived copy |accessdate=6 October 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20130915174902/http://www.circleofblue.org/waternews/wp-content/uploads/2010/08/Webber-water-in-transportation.pdf |archivedate=15 September 2013 |df= }}</ref> ===Toxicity=== The [[safety data sheet]] for a 2003 [[Texas|Texan]] unleaded gasoline shows at least 15 hazardous chemicals occurring in various amounts, including [[benzene]] (up to 5% by volume), [[toluene]] (up to 35% by volume), [[naphthalene]] (up to 1% by volume), [[1,2,4-Trimethylbenzene|trimethylbenzene]] (up to 7% by volume), [[Methyl tert-butyl ether|methyl ''tert''-butyl ether]] (MTBE) (up to 18% by volume, in some states) and about ten others.<ref>[http://firstfuelbank.com/msds/Tesoro.pdf Material safety data sheet] {{webarchive|url=https://web.archive.org/web/20070928104058/http://firstfuelbank.com/msds/Tesoro.pdf |date=28 September 2007 }} Tesoro petroleum Companies, Inc., U.S., 8 February 2003</ref> Hydrocarbons in gasoline generally exhibit low acute toxicities, with [[LD50]] of 700–2700&nbsp;mg/kg for simple aromatic compounds.<ref>Karl Griesbaum et al. "Hydrocarbons" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a13_227}}</ref> Benzene and many antiknocking additives are [[carcinogenic]]. People can be exposed to gasoline in the workplace by swallowing it, breathing in vapors, skin contact, and eye contact. Gasoline is toxic. The [[National Institute for Occupational Safety and Health]] (NIOSH) has also designated gasoline as a carcinogen.<ref>{{cite web|title = CDC – NIOSH Pocket Guide to Chemical Hazards – Gasoline|url = https://www.cdc.gov/niosh/npg/npgd0299.html|website = www.cdc.gov|accessdate = 3 November 2015|deadurl = no|archiveurl = https://web.archive.org/web/20151016080051/http://www.cdc.gov/niosh/npg/npgd0299.html|archivedate = 16 October 2015|df = dmy-all}}</ref>Physical contact, ingestion or inhalation can cause health problems. Since ingesting gasoline can cause permanent damage to major organs, a call to a local poison control center or emergency room visit is indicated.<ref>https://www.healthline.com/health/gasoline</ref> Contrary to common misconception, swallowing gasoline doesn't generally require special emergency treatment, and inducing vomiting doesn't help, and can make it worse. Acording to poison specialist Brad Dahl, "even two mouthfuls wouldn't be that dangerous as long as it goes down to your stomach and stays there or keeps going."<ref>https://healthcare.utah.edu/the-scope/shows.php?shows=0_g9tzppx4</ref> ===Inhalation for intoxication=== [[Inhalant|Inhaled (huffed)]] gasoline vapor is a common intoxicant. Users concentrate and inhale gasoline vapour in a manner not intended by the manufacturer to produce [[euphoria]] and [[Substance intoxication|intoxication]]. Gasoline inhalation has become epidemic in some poorer communities and indigenous groups in Australia, Canada, New Zealand, and some Pacific Islands.<ref name="gasoline Sniffing Fact File">[http://www.abc.net.au/health/library/stories/2005/24/11/1831506.htm gasoline Sniffing Fact File] Sheree Cairney, www.abc.net.au, Published 24 November 2005. Retrieved 13 October 2007, a modified version of [http://www.abc.net.au/health/library/gasoline_ff.htm the original article] {{dead link|date=August 2017|bot=medic}}{{cbignore|bot=medic}}, now archived [http://www.abc.net.au/health/library/gasoline_ff.htm]</ref> The practice is thought to cause severe organ damage, including mental retardation.<ref>{{cite web|url=https://www.researchgate.net/publication/7873998_Low_IQ_and_Gasoline_Huffing_The_Perpetuation_Cycle|title=Low IQ and Gasoline Huffing: The Perpetuation Cycle|publisher=|deadurl=no|archiveurl=https://web.archive.org/web/20170814215234/https://www.researchgate.net/publication/7873998_Low_IQ_and_Gasoline_Huffing_The_Perpetuation_Cycle|archivedate=14 August 2017|df=dmy-all}}</ref><ref>{{cite web|url=https://www.addiction.com/3385/gas-sniffing-form-substance-abuse/|title=Rising Trend: Sniffing Gasoline - Huffing & Inhalants|date=16 May 2013|publisher=|deadurl=no|archiveurl=https://web.archive.org/web/20161220203248/https://www.addiction.com/3385/gas-sniffing-form-substance-abuse/|archivedate=20 December 2016|df=dmy-all}}</ref><ref>{{cite web|url=http://alcoholrehab.com/drug-addiction/petrol-sniffing-gasoline-sniffing/|title=Petrol Sniffing / Gasoline Sniffing|publisher=|deadurl=no|archiveurl=https://web.archive.org/web/20161221072052/http://alcoholrehab.com/drug-addiction/petrol-sniffing-gasoline-sniffing/|archivedate=21 December 2016|df=dmy-all}}</ref> In Canada, Native children in the isolated Northern Labrador community of [[Davis Inlet, Newfoundland and Labrador|Davis Inlet]] were the focus of national concern in 1993, when many were found to be sniffing gasoline. The Canadian and provincial [[Newfoundland and Labrador]] governments intervened on a number of occasions, sending many children away for treatment. Despite being moved to the new community of [[Natuashish, Newfoundland and Labrador|Natuashish]] in 2002, serious inhalant abuse problems have continued. Similar problems were reported in [[Sheshatshiu, Newfoundland and Labrador|Sheshatshiu]] in 2000 and also in [[Pikangikum First Nation]].<ref>{{cite web|url=http://www.mcscs.jus.gov.on.ca/english/DeathInvestigations/office_coroner/PublicationsandReports/Pikangikum/PIK_report.html |last=Lauwers |first=Bert |title=The Office of the Chief Coroner's Death Review of the Youth Suicides at the Pikangikum First Nation, 2006 – 2008 |publisher=Office of the Chief Coroner of Ontario |date=1 June 2011 |accessdate=2 October 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120930122313/http://www.mcscs.jus.gov.on.ca//english/DeathInvestigations/office_coroner/PublicationsandReports/Pikangikum/PIK_report.html |archivedate=30 September 2012 |df= }}</ref> In 2012, the issue once again made the news media in Canada.<ref>{{cite web|url=http://www.cbc.ca/news/canada/newfoundland-labrador/story/2012/06/18/nl-natuashish-sniffing-618.html|title=Labrador Innu kids sniffing gas again to fight boredom|publisher=[[CBC.ca]]|accessdate=18 June 2012|deadurl=no|archiveurl=https://web.archive.org/web/20120618224149/http://www.cbc.ca/news/canada/newfoundland-labrador/story/2012/06/18/nl-natuashish-sniffing-618.html|archivedate=18 June 2012|df=dmy-all}}</ref> {{see also|Indigenous Australian#Substance abuse}} Australia has long faced a petrol (gasoline) sniffing problem in isolated and impoverished [[Australian Aborigines|aboriginal]] communities. Although some sources argue that sniffing was introduced by [[United States]] [[soldier|servicemen]] stationed in the nation's [[Top End]] during [[World War II]]<ref>{{cite journal | last = Wortley | first = R. P. | title = Anangu Pitjantjatjara Yankunytjatjara Land Rights (Regulated Substances) Amendment Bill | journal = Legislative Council (South Australia) | publisher = Hansard |date= 29 August 2006 | url = http://www.parliament.sa.gov.au/SAN/Attachments/Hansard/2006/LC/WH290806.LC.htm | accessdate = 27 December 2006 | format = – ^{[https://scholar.google.co.uk/scholar?hl=en&lr=&q=author%3AWortley+intitle%3AAnangu+Pitjantjatjara+Yankunytjatjara+Land+Rights+%28Regulated+Substances%29+Amendment+Bill&as_publication=Legislative+Council+%28South+Australia%29&as_ylo=&as_yhi=&btnG=Search Scholar search]} |archiveurl = https://web.archive.org/web/20070929121901/http://www.parliament.sa.gov.au/SAN/Attachments/Hansard/2006/LC/WH290806.LC.htm |archivedate = 29 September 2007}}</ref> or through experimentation by 1940s-era [[Cobourg Peninsula]] sawmill workers,<ref>{{cite journal |last=Brady |first=Maggie |title=Community Affairs Reference Committee Reference: Petrol sniffing in remote Aboriginal communities |page=11 |journal=Official Committee Hansard (Senate) |publisher=Hansard |date=27 April 2006 |url=http://www.aph.gov.au/hansard/senate/commttee/S9271.pdf |accessdate=20 March 2006 |format=PDF |deadurl=yes |archiveurl=https://web.archive.org/web/20060912011023/http://www.aph.gov.au/hansard/senate/commttee/S9271.pdf |archivedate=12 September 2006 |df= }}</ref> other sources claim that inhalant abuse (such as glue inhalation) emerged in Australia in the late 1960s.{{citation needed|date=May 2017}} Chronic, heavy petrol sniffing appears to occur among remote, impoverished [[indigenous Australians|indigenous]] communities, where the ready accessibility of petrol has helped to make it a common substance for abuse. In Australia, petrol sniffing now occurs widely throughout remote Aboriginal communities in the [[Northern Territory]], [[Western Australia]], northern parts of [[South Australia]] and [[Queensland]]. The number of people sniffing petrol goes up and down over time as young people experiment or sniff occasionally. "Boss", or chronic, sniffers may move in and out of communities; they are often responsible for encouraging young people to take it up.<ref>{{cite web |last = Williams |first = Jonas |title = Responding to petrol sniffing on the Anangu Pitjantjatjara Lands: A case study |work = Social Justice Report 2003 |publisher = Human Rights and Equal Opportunity Commission |date = March 2004 |url = http://www.humanrights.gov.au/social_justice/sj_report/sjreport03/chap4.html |accessdate = 27 December 2006 |deadurl = no |archiveurl = https://web.archive.org/web/20070831173214/http://humanrights.gov.au/social_justice/sj_report/sjreport03/chap4.html |archivedate = 31 August 2007 |df = dmy-all }}</ref> In 2005, the [[Government of Australia]] and [[BP|BP Australia]] began the usage of [[Opal (fuel)|Opal fuel]] in remote areas prone to petrol sniffing.<ref>[http://www.aph.gov.au/senate/Committee/clac_ctte/petrol_sniffing/submissions/sub03.pdf Submission to the Senate Community Affairs References Committee by BP Australia Pty Ltd] {{webarchive|url=https://web.archive.org/web/20070614103002/http://www.aph.gov.au/Senate/committee/clac_ctte/petrol_sniffing/submissions/sub03.pdf |date=14 June 2007 }} Parliament of Australia Web Site. Retrieved 8 June 2007.</ref> Opal is a non-sniffable fuel (which is much less likely to cause a high) and has made a difference in some indigenous communities. ===Flammability=== [[File:gasoline-fire.png|thumb|upright=1.15|Uncontrolled burning of gasoline produces large quantities of [[soot]] and [[carbon monoxide]]]] Like other hydrocarbons, gasoline burns in a limited range of its vapor phase and, coupled with its volatility, this makes leaks highly dangerous when sources of ignition are present. Gasoline has a [[lower explosive limit]] of 1.4% by volume and an [[upper explosive limit]] of 7.6%. If the concentration is below 1.4%, the air-gasoline mixture is too lean and does not ignite. If the concentration is above 7.6%, the mixture is too rich and also does not ignite. However, gasoline vapor rapidly mixes and spreads with air, making unconstrained gasoline quickly flammable. ==Use and pricing== {{Main|Gasoline and diesel usage and pricing|Peak oil}} The United States accounts for about 44% of the world’s gasoline consumption.<ref>{{cite web |url=http://www.worldwatch.org/node/5579 |title=Archived copy |accessdate=2014-02-15 |deadurl=no |archiveurl=https://web.archive.org/web/20131013141752/http://www.worldwatch.org/node/5579 |archivedate=13 October 2013 |df=dmy-all }}, {{cite web |url=http://www.eia.doe.gov/emeu/international/oilconsumption.html |title=Archived copy |accessdate=2007-12-20 |deadurl=no |archiveurl=https://web.archive.org/web/20071212204424/http://www.eia.doe.gov/emeu/international/oilconsumption.html |archivedate=12 December 2007 |df=dmy-all }}</ref> In 2003, the United States consumed {{convert|476|GL|e9USgal+e9impgal|abbr=off|sp=us|lk=on}},<ref>{{cite web|url=http://earthtrends.wri.org/text/energy-resources/variable-291.html |title=EarthTrends: Energy and Resources—Transportation: Motor gasoline consumption Units: Million liters |publisher= |deadurl=yes |archiveurl=https://web.archive.org/web/20070927000755/http://earthtrends.wri.org/text/energy-resources/variable-291.html |archivedate=27 September 2007 |df= }}</ref> which equates to {{convert|1.3|GL|e6USgal+e6impgal|abbr=off|sp=us}} of gasoline each day. The United States used about {{convert|510|GL|e9USgal+e9impgal|abbr=off|sp=us}} of gasoline in 2006, of which 5.6% was mid-grade and 9.5% was premium grade.<ref>{{cite web|url=http://tonto.eia.doe.gov/dnav/pet/pet_cons_prim_dcu_nus_a.htm|title=U.S. Prime Supplier Sales Volumes of petroleum Products|publisher=United States Energy Information Administration|accessdate=24 October 2007|deadurl=no|archiveurl=https://web.archive.org/web/20071015072028/http://tonto.eia.doe.gov/dnav/pet/pet_cons_prim_dcu_nus_a.htm|archivedate=15 October 2007|df=dmy-all}}</ref> ===Europe=== Countries in Europe impose substantially higher [[fuel tax|tax]]es on fuels such as gasoline when compared to the United States. The price of gasoline in Europe is typically higher than that in the U.S. due to this difference. ===United States=== {{update-section|date=April 2016}} From 1998 to 2004, the price of gasoline fluctuated between [[US$]]1 and US$2 per [[U.S. gallon]].<ref name="FE.gov">{{cite web|url=http://www.fueleconomy.gov/feg/gasprices/faq.shtml#History|title=Gas Prices: Frequently Asked Questions|work=fueleconomy.gov|deadurl=no|archiveurl=https://web.archive.org/web/20110121193757/http://fueleconomy.gov/feg/gasprices/FAQ.shtml#History|archivedate=21 January 2011|df=dmy-all}}</ref> After 2004, the price increased until the average gas price reached a high of $4.11 per U.S. gallon in mid-2008, but receded to approximately $2.60 per U.S. gallon by September 2009.<ref name="FE.gov" /> More recently, the U.S. experienced an upswing in gasoline prices through 2011,<ref name="taxfoundation.org">{{cite web|url=http://www.taxfoundation.org/UserFiles/Image/Fiscal%20Facts/gas-tax-690px.jpg |title=Archived copy |accessdate=12 June 2009 |deadurl=yes |archiveurl=https://web.archive.org/web/20090706073258/http://www.taxfoundation.org/UserFiles/Image/Fiscal%20Facts/gas-tax-690px.jpg |archivedate=6 July 2009 |df= }}</ref> and by 1 March 2012, the national average was $3.74 per gallon. In the United States, most consumer goods bear pre-tax prices, but gasoline prices are posted with taxes included. Taxes are added by federal, state, and local governments. As of 2009, the federal tax is 18.4¢ per gallon for gasoline and 24.4¢ per gallon for [[diesel fuel|diesel]] (excluding [[red diesel]]).<ref>{{cite web |url=http://www.fhwa.dot.gov/infrastructure/gastax.cfm |title=When did the Federal Government begin collecting the gas tax?—Ask the Rambler — Highway History |publisher=FHWA |date= |accessdate=17 October 2010 |deadurl=no |archiveurl=https://web.archive.org/web/20100529003035/http://www.fhwa.dot.gov/infrastructure/gastax.cfm |archivedate=29 May 2010 |df=dmy-all }}</ref> Among individual states, the highest gasoline tax rates, including the federal taxes as of 2005, are found in [[New York (state)|New York]] (62.9¢/gal), [[Hawaii]] (60.1¢/gal) and [[California]] (60¢/gal).<ref name="taxfoundation.org"/> About 9 percent of all gasoline sold in the U.S. in May 2009 was premium grade, according to the Energy Information Administration. ''[[Consumer Reports]]'' magazine says, "If [your owner’s manual] says to use regular fuel, do so—there's no advantage to a higher grade."<ref>{{cite web|url=http://www.consumerreports.org/cro/cars/tires-auto-parts/car-maintenance/save-at-the-pump/overview/save-at-the-pump-ov.htm|title=New & Used Car Reviews & Ratings|work=Consumer Reports|deadurl=no|archiveurl=https://web.archive.org/web/20130223032546/http://www.consumerreports.org/cro/cars/tires-auto-parts/car-maintenance/save-at-the-pump/overview/save-at-the-pump-ov.htm|archivedate=23 February 2013|df=dmy-all}}</ref> The ''Associated Press'' said premium gas—which has a higher octane rating and costs more per gallon than regular unleaded—should be used only if the manufacturer says it is "required".<ref>{{cite web|url=http://www.philly.com/philly/business/personal_finance/081909_premium_gas.html |title=Gassing up with premium probably a waste |date=19 August 2009 |work=philly.com |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20090821162543/http://www.philly.com/philly/business/personal_finance/081909_premium_gas.html |archivedate=21 August 2009 |df= }}</ref> Cars with [[turbocharger|turbocharged]] engines and high compression ratios often specify premium gas because higher octane fuels reduce the incidence of "knock", or fuel pre-detonation.<ref>{{cite web|url=http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-premium-g|title=Fact or Fiction?: Premium Gasoline Delivers Premium Benefits to Your Car|first=David|last=Biello|work=Scientific American|deadurl=no|archiveurl=https://web.archive.org/web/20121012015036/http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-premium-g|archivedate=12 October 2012|df=dmy-all}}</ref> The price of gas varies considerably between the summer and winter months.<ref>{{cite web|url=http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/summer-fuel.htm|title=Why is summer fuel more expensive than winter fuel?|publisher=[[HowStuffWorks]]|deadurl=no|archiveurl=https://web.archive.org/web/20150530115419/http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/summer-fuel.htm|archivedate=30 May 2015|df=dmy-all}}</ref> ==Carbon dioxide production== About {{convert|19.64|lb|kg}} of [[carbon dioxide]] (CO₂) are produced from burning {{convert|1|gal|liter|abbr=off}} of gasoline that does not contain ethanol (2.36&nbsp;kg/L). About {{convert|22.38|lb|kg}} of CO₂ are produced from burning one US gallon of diesel fuel (2.69&nbsp;kg/l).<ref name="US Energy Information Administration"/> The U.S. [[Energy Information Administration|EIA]] estimates that U.S. motor gasoline and diesel (distillate) fuel consumption for transportation in 2015 resulted in the emission of about 1,105 million metric tons of CO₂ and 440 million metric tons of CO₂, respectively, for a total of 1,545 million metric tons of CO₂.<ref name="US Energy Information Administration"/> This total was equivalent to 83% of total U.S. transportation-sector CO₂ emissions and equivalent to 29% of total U.S. energy-related CO₂ emissions in 2015.<ref name="US Energy Information Administration"/> Most of the retail gasoline now sold in the United States contains about 10% fuel ethanol (or E10) by volume.<ref name="US Energy Information Administration"/> Burning a gallon of E10 produces about {{convert|17.68|lb|kg}} of CO₂ that is emitted from the fossil fuel content. If the CO₂ emissions from ethanol combustion are considered, then about {{convert|18.95|lb|kg}} of CO₂ are produced when a gallon of E10 is combusted.<ref name="US Energy Information Administration"/> About {{convert|12.73|lb|kg}} of CO₂ are produced when a gallon of pure ethanol is combusted.<ref name="US Energy Information Administration"/> ==Comparison with other fuels== {{See also|Energy content of biofuel}} <!--Note: I modified this table because the values in SI units didn't agree with the values in British or US units. So I used another source (Oak Ridge reference), but it did not have MJ/kg, and I did not have the time to try to find accurate densities in order to convert to MJ/kg. If someone can fill in the blanks using good data, it would be useful. --> Below is a table of the volumetric and mass [[energy density]] of various transportation fuels as compared with gasoline. In the rows with [[higher heating value|gross]] and [[lower heating value|net]], they are from the [[Oak Ridge National Laboratory]]'s Transportation Energy Data Book.<ref name=TEDB>{{cite web|url=http://cta.ornl.gov/data/appendix_b.shtml|title=Appendix B – Transportation Energy Data Book|work=ornl.gov|deadurl=no|archiveurl=https://web.archive.org/web/20110718143536/http://cta.ornl.gov/data/appendix_b.shtml|archivedate=18 July 2011|df=dmy-all}}</ref> {| class="wikitable sortable"<!--please cleanup this table to enable sorting: non-numeric characters that break sorting should be removed or moved to non-numeric sorting columns--> |- ! style="text-align:left;"|Fuel type{{Clarify|date=June 2009|reason=need specific compositions of each fuel, plus cites, to avoid vagueness in numbers}} ! style="text-align:right;"|Gross MJ/[[liter|l]] ! style="text-align:right;"|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;MJ/kg ! Gross [[British thermal unit|BTU]]/[[imperial gallon|gal]]<br>(imp) ! Gross BTU/[[US gallon|gal]]<br>(U.S.) ! Net BTU/gal (U.S.) ! style="text-align:right;"|&nbsp;&nbsp;&nbsp;&nbsp;[[octane rating|RON]] |- | Conventional gasoline | style="text-align:right;"|34.8 | style="text-align:right;"|44.4<ref name=Thomas>Thomas, George: {{cite web|url=http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf |title=Overview of Storage Development DOE Hydrogen Program |deadurl=yes |archiveurl=https://web.archive.org/web/20070221185632/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf |archivedate=21 February 2007 |df= }}&nbsp;{{small|(99.6&nbsp;KB)}}. Livermore, CA. Sandia National Laboratories. 2000.</ref> | style="text-align:right;"|150,100 | style="text-align:right;"|125,000 | style="text-align:right;"|115,400 | style="text-align:right;"|91–92 |- | [[Autogas]] ([[Liquified petroleum gas|LPG]]) (Consisting mostly of C3 and C4 hydrocarbons) | style="text-align:right;"|26.8 | style="text-align:right;"|46 | style="text-align:right;"| | style="text-align:right;"|95,640 | style="text-align:right;"| | style="text-align:right;"|108 |- |[[ethanol fuel|Ethanol]] | style="text-align:right;"|21.2<ref name=Thomas /> | style="text-align:right;"|26.8<ref name=Thomas /> | style="text-align:right;"|101,600 | style="text-align:right;"|84,600 | style="text-align:right;"|75,700 | style="text-align:right;"|108.7<ref name='Fuel 89 (2010) 2713-2720'>{{cite journal | doi = 10.1016/j.fuel.2010.01.032 | title = Impact of alcohol–gasoline fuel blends on the performance and combustion characteristics of an SI engine | year = 2010 | last1 = Eyidogan | first1 = Muharrem | last2 = Ozsezen | first2 = Ahmet Necati | last3 = Canakci | first3 = Mustafa | last4 = Turkcan | first4 = Ali | journal = Fuel | volume = 89 | issue = 10 | page = 2713}}</ref> <!-- remove incorrect citation of 113<ref name='Texas Energy Conservation Office'>{{cite web | url = http://www.seco.cpa.state.tx.us/re_ethanol.htm | title = Ethanol | accessdate =6 October 2010}}</ref> --> |- | [[Methanol]] | style="text-align:right;"|17.9 | style="text-align:right;"|19.9<ref name=Thomas/> | style="text-align:right;"|77,600 | style="text-align:right;"|64,600 | style="text-align:right;"|56,600 | style="text-align:right;"|123 |- | [[Butanol fuel|Butanol]]{{ref}} | style="text-align:right;"|29.2 | style="text-align:right;"|36.6 | style="text-align:right;"|125,819 | style="text-align:right;"|104,766 | style="text-align:right;"| | style="text-align:right;"|91–99{{Clarify|date=June 2009|reason=need specific compositions of each fuel, plus cites, to avoid vagueness in numbers; pure n-butanol only has one rating; otherwise split into two Butanol mixes}} |- | [[Alcohol fuel|Gasohol]] | style="text-align:right;"|31.2 | style="text-align:right;"| | style="text-align:right;"|145,200 | style="text-align:right;"|120,900 | style="text-align:right;"|112,400 | style="text-align:right;"|93/94{{Clarify|date=June 2009|reason=can only be one figure, cites would help}} |- | [[Diesel fuel|Diesel]](*) | style="text-align:right;"|38.6 | style="text-align:right;"|45.4 | style="text-align:right;"|166,600 | style="text-align:right;"|138,700 | style="text-align:right;"|128,700 | style="text-align:right;"|25 |- | [[Biodiesel]] | style="text-align:right;"|33.3–35.7<ref>{{cite web|url=http://www.ces.ncsu.edu/forestry/biomass/pubs/WB0008.pdf|archive-url=https://web.archive.org/web/20121122142254/http://www.ces.ncsu.edu/forestry/biomass/pubs/WB0008.pdf|dead-url=yes|archive-date=22 November 2012|title=Extension Forestry - North Carolina Cooperative Extension|publisher=}}</ref>{{Clarify|date=June 2009|reason=need specific composition, plus cite, to avoid vagueness in numbers; otherwise remove this as uninformative}} | style="text-align:right;"| | style="text-align:right;"| | style="text-align:right;"|126,200 | style="text-align:right;"|117,100 | style="text-align:right;"| |- | [[Avgas]] (high octane gasoline) | style="text-align:right;"|33.5 | style="text-align:right;"|46.8 | style="text-align:right;"|144,400 | style="text-align:right;"|120,200 | style="text-align:right;"|112,000 | style="text-align:right;"| |- | [[Aviation fuel#Energy content|Jet fuel (kerosene based)]] | style="text-align:right;"|35.1 | style="text-align:right;"|43.8 | style="text-align:right;"|151,242 | style="text-align:right;"|125,935 | style="text-align:right;"| | style="text-align:right;"| |- | [[Aviation fuel#Energy content|Jet fuel (naphtha)]] | style="text-align:right;"| | style="text-align:right;"| | style="text-align:right;"| | style="text-align:right;"|127,500 | style="text-align:right;"|118,700 | style="text-align:right;"| |- | [[Liquefied natural gas]] | style="text-align:right;"|25.3 | style="text-align:right;"|~55 | style="text-align:right;"|109,000 | style="text-align:right;"|90,800 | style="text-align:right;"| | style="text-align:right;"| |- | [[Liquefied petroleum gas]] | style="text-align:right;"| | style="text-align:right;"|46.1 | style="text-align:right;"| | style="text-align:right;"|91,300 | style="text-align:right;"|83,500 | style="text-align:right;"| |- | [[Hydrogen]] | style="text-align:right;"|10.1 (at 20 kelvin) | style="text-align:right;"|142 | style="text-align:right;"| | style="text-align:right;"| | style="text-align:right;"|130<ref>{{cite web|url=http://www.hydrogenassociation.org/general/faqs.asp |title=The National Hydrogen Association |date=25 November 2005 |publisher= |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20051125094124/http://www.hydrogenassociation.org/general/faqs.asp |archivedate=25 November 2005 |df= }}</ref> |} <small>(*) Diesel fuel is not used in a gasoline engine, so its low octane rating is not an issue; the relevant metric for diesel engines is the [[cetane number]].</small> ==See also== {{Portal|Energy}} {{cmn|colwidth=22em| * [[Aviation fuel]] * [[Butanol fuel]] – replacement fuel for use in unmodified gasoline engines * [[Diesel fuel]] * [[Filling station]] * [[Fuel dispenser]] * [[Fuel saving device]] * [[Gasoline and diesel usage and pricing]] * [[Gasoline gallon equivalent]] * [[Internal combustion engine]] (ICE) * [[Jerrycan]] * [[List of automotive fuel brands]] * [[List of gasoline additives]] * [[Natural-gas condensate#Drip gas]] * [[Octane rating]] * [[World oil market chronology from 2003]] }} ==References== {{reflist}} ===Bibliography=== {{refbegin}} * Gold, Russell. ''The Boom: How Fracking Ignited the American Energy Revolution and Changed the World'' (Simon & Schuster, 2014). * Yergin, Daniel. ''[[The Quest: Energy, Security, and the Remaking of the Modern World]]'' (Penguin, 2011). * Yergin, Daniel. ''[[The Prize: The Epic Quest for Oil, Money, and Power]]'' (Buccaneer Books, 1994; latest edition: Reissue Press, 2008). * [http://zfacts.com/p/35.html Graph of inflation-corrected historic prices, 1970–2005. Highest in 2005] * [https://web.archive.org/web/20070917190316/http://www.ftc.gov/bcp/edu/pubs/consumer/autos/aut12.shtm The Low-Down on High Octane Gasoline] * [http://www.epa.gov/otaq/regs/fuels/additive/mmt_cmts.htm MMT-US EPA] * An [http://www.gasresources.net/Introduction.htm introduction to the modern petroleum science], and to the Russian-Ukrainian theory of deep, [[abiotic petroleum]] origins. * [http://www.straightdope.com/columns/041008.html What's the difference between premium and regular gas?] (from [[The Straight Dope]]) * [http://i-r-squared.blogspot.com/2006/09/here-comes-winter-gasoline.html "Here Comes Winter Gasoline" R-Squared Energy Blog] 14 September 2006 * [https://web.archive.org/web/20051109151831/http://www.gtz.de/en/themen/umwelt-infrastruktur/transport/10285.htm International Fuel Prices 2005] with diesel and gasoline prices of 172 countries * [https://web.archive.org/web/20010815085245/http://tonto.eia.doe.gov/oog/info/gdu/gasdiesel.asp EIA—Gasoline and Diesel Fuel Update] * [https://web.archive.org/web/20060614021021/http://soc.hfac.uh.edu/artman/publish/article_375.shtml World Internet News: "Big Oil Looking for Another Government Handout", April 2006.] * [http://journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html#table Durability of various plastics: Alcohols vs. Gasoline] * [https://web.archive.org/web/20030221233432/http://www.gasresources.net/DisposalBioClaims.htm Dismissal of the Claims of a Biological Connection for Natural petroleum.] * [https://www.epa.gov/OMSWWW/rfgecon.htm Fuel Economy Impact Analysis of RFG] i.e. reformulated gasoline. Has lower heating value data, actual energy content is higher see [[higher heating value]] {{refend}} ==External links== {{Commons|Gasoline}} {{Wiktionary|gasoline}} * [http://money.cnn.com/pf/features/lists/global_gasprices/ CNN/Money: Global gas prices] * [http://www.energy.eu/#Prices EEP: European gas prices] * [http://cta.ornl.gov/data/index.shtml Transportation Energy Data Book] * [http://www.energysupplylogistics.com/terminals Energy Supply Logistics Searchable Directory of US Terminals] * [http://robotpig.net/__automotive/fuel.php High octane fuel, leaded and LRP gasoline—article from robotpig.net] * [https://www.cdc.gov/niosh/npg/npgd0299.html CDC – NIOSH Pocket Guide to Chemical Hazards] * [http://www.globalair.com/airport/fuelmap.aspx Aviation Fuel Map] '''Images''' * ''[https://archive.org/movies/details-db.php?collection=prelinger&collectionid=19334&from=collectionSpotlight Down the Gasoline Trail]'' Handy Jam Organization, 1935 (Cartoon) {{Motor fuel}} {{Authority control}} [[Category:IARC Group 2B carcinogens]] [[Category:Liquid fuels]] [[Category:Petroleum products]] [[Category:Inhalants]]'