Diesel oil redirects here. Sometimes “diesel oil” is used to mean lubricating oil for diesel engines.

Diesel fuel ( /ˈdiːzəl/) in general is any liquid fuel used in diesel engines. The most common is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel, are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is increasingly called petrodiesel.^[1] Ultra-low sulfur diesel (ULSD) is a standard for defining diesel fuel with substantially lowered sulfur contents. As of 2007, almost all diesel fuel available in the United States of America, Canada and Europe is the ULSD type.

In the UK, diesel fuel for on-road use is commonly abbreviated DERV, standing for Diesel Engined Road Vehicle, which carries a tax premium over equivalent fuel for non-road use (see Taxation).^[2]

Contents 1 History 1.1 Etymology 1.2 Diesel engine 2 Sources 2.1 Petroleum diesel 2.1.1 Refining 2.1.2 Fuel value and price 2.1.3 Use as vehicle fuel 2.1.4 Use as car fuel 2.1.5 Reduction of sulfur emissions 2.1.6 Environment hazards of sulfur 2.1.7 Chemical composition 2.1.8 Algae, microbes, and water contamination 2.1.9 Road hazard 2.2 Synthetic diesel 2.3 FAME 2.4 Hydrogenated oils and fats 2.5 DME 3 Transportation and storage 3.1 Railroad 3.2 Aircraft 3.3 Storage 4 Other uses 5 Emissions 6 Taxation 7 See also 8 References 9 External links

History

Etymology

The word “diesel” is derived from the family name of German inventor Rudolf Diesel who in 1892 invented the diesel engine.^[3]

Diesel engine

Diesel engines are a type of internal combustion engine. Rudolf Diesel originally designed the diesel engine to use coal dust as a fuel. He also experimented with various oils, including some vegetable oils,^[4] such as peanut oil, which was used to power the engines which he exhibited at the 1900 Paris Exposition and the 1911 World’s Fair in Paris.^[5]

Sources

Diesel fuel is produced from petroleum and from various other sources.

Petroleum diesel

Refining

Petroleum diesel, also called petrodiesel,^[6] or fossil diesel is produced from the fractional distillation of crude oil between 200 °C (392 °F) and 350 °C (662 °F) at atmospheric pressure, resulting in a mixture of carbon chains that typically contain between 8 and 21 carbon atoms per molecule.^[7]

Fuel value and price

As of 2010, the density of petroleum diesel is about 0.832 kg/l (6.943 lb/US gal), about 12% more than ethanol-free petrol (gasoline), which has a density of about 0.745 kg/l (6.217 lb/US gal). About 86.1% of the fuel mass is carbon, and when burned, it offers a net heating value of 43.1 MJ/kg as opposed to 43.2 MJ/kg for gasoline. However, due to the higher density, diesel offers a higher volumetric energy density at 35.86 MJ/L (128 700 BTU/US gal) vs. 32.18 MJ/L (115 500 BTU/US gal) for gasoline, some 11% higher, which should be considered when comparing the fuel efficiency by volume. The CO₂ emissions from diesel are 73.25 g/MJ, just slightly lower than for gasoline at 73.38 g/MJ.^[8] Diesel is generally simpler to refine from petroleum than gasoline, and contains hydrocarbons having a boiling point in the range of 180-360°C (360-680°F). The price of diesel traditionally rises during colder months as demand for heating oil rises, which is refined in much the same way. Because of recent changes in fuel quality regulations, additional refining is required to remove sulfur, which contributes to a sometimes higher cost. In many parts of the United States and throughout the United Kingdom and Australia,^[9] diesel may be priced higher than petrol.^[10] Reasons for higher-priced diesel include the shutdown of some refineries in the Gulf of Mexico, diversion of mass refining capacity to gasoline production, and a recent transfer to ultra-low sulfur diesel (ULSD), which causes infrastructural complications.^[11] In Sweden, a diesel fuel designated as MK-1 (class 1 environmental diesel) is also being sold; this is a ULSD that also has a lower aromatics content, with a limit of 5%.^[12] This fuel is slightly more expensive to produce than regular ULSD.

Use as vehicle fuel

Unlike petroleum ether and liquefied petroleum gas engines, diesel engines do not use high-voltage spark ignition (spark plugs). An engine running on diesel compresses the air inside the cylinder to high pressures and temperatures (compression ratios from 14:1 to 18:1 are common in current diesel engines); the engine generally injects the diesel fuel directly into the cylinder, starting a few degrees before top dead center (TDC) and continuing during the combustion event. The high temperatures inside the cylinder cause the diesel fuel to react with the oxygen in the mix (burn or oxidize), heating and expanding the burning mixture to convert the thermal/pressure difference into mechanical work, i.e., to move the piston. Engines have glow plugs to help start the engine by preheating the cylinders to a minimum operating temperature. Diesel engines are lean burn engines^[13], burning the fuel in more air than is required for the chemical reaction. They thus use less fuel than rich burn spark ignition engines which use a Stoichiometric air-fuel ratio (just enough air to react with the fuel). Because they have high compression ratios and no throttle, diesel engines are more efficient than many spark-ignited engines^{[citation needed]}.

Gas turbine internal combustion engines can also take diesel fuel, as can some other types of internal combustion. External combustion engines can easily use diesel fuel as well.

This efficiency^[14] and its lower flammability than gasoline^[15] are the two main reasons for military use of diesel in armored fighting vehicles. Engines running on diesel also provide more torque, and are less likely to stall, as they are controlled by a mechanical or electronic governor^{[citation needed]}.

A disadvantage of diesel as a vehicle fuel in cold climates, compared to gasoline or other petroleum-derived fuels, is that its viscosity increases quickly as the fuel’s temperature decreases, turning into a non-flowing gel (see Compression Ignition – Gelling) at temperatures as high as -19 °C (-2.2 °F) or -15 °C (5 °F), which cannot be pumped by regular fuel pumps. Special low-temperature diesel contains additives to keep it in a more liquid state at lower temperatures, but starting a diesel engine in very cold weather may still pose considerable difficulties.

Another disadvantage of diesel engines compared to petrol/gasoline engines is the possibility of runaway failure. Since diesel engines do not require spark ignition, they can sustain operation as long as diesel fuel is supplied. Fuel is typically supplied via a fuel pump. If the pump breaks down in an “open” position, the supply of fuel will be unrestricted, and the engine will runaway and risk terminal failure.^[16] (In vehicles or installations that use both diesel engines and bottled gas, a gas leak into the engine room could also provide fuel for a runaway, via the engine air intake.^[17])

Use as car fuel

Diesel-powered cars generally have a better fuel economy than equivalent gasoline engines and produce less greenhouse gas emission. Their greater economy is due to the higher energy per-litre content of diesel fuel and the intrinsic efficiency of the diesel engine. While petrodiesel’s higher density results in higher greenhouse gas emissions per litre compared to gasoline,^[18] the 20–40% better fuel economy achieved by modern diesel-engined automobiles offsets the higher per-litre emissions of greenhouse gases, and a diesel-powered vehicle emits 10-20 percent less greenhouse gas than comparable gasoline vehicles.^[19][20][21] Biodiesel-powered diesel engines offer substantially improved emission reductions compared to petrodiesel or gasoline-powered engines, while retaining most of the fuel economy advantages over conventional gasoline-powered automobiles. However, the increased compression ratios mean there are increased emissions of oxides of nitrogen (NO_x) from diesel engines. This is compounded by biological nitrogen in biodiesel to make NO_x emissions the main drawback of diesel versus gasoline engines.^{[citation needed]}

Reduction of sulfur emissions

In the past, diesel fuel contained higher quantities of sulfur. European emission standards and preferential taxation have forced oil refineries to dramatically reduce the level of sulfur in diesel fuels. In the United States, more stringent emission standards have been adopted with the transition to ULSD starting in 2006, and becoming mandatory on June 1, 2010 (see also diesel exhaust). U.S. diesel fuel typically also has a lower cetane number (a measure of ignition quality) than European diesel, resulting in worse cold weather performance and some increase in emissions.^[22]

Environment hazards of sulfur

High levels of sulfur in diesel are harmful for the environment because they prevent the use of catalytic diesel particulate filters to control diesel particulate emissions, as well as more advanced technologies, such as nitrogen oxide (NO_x) adsorbers (still under development), to reduce emissions. Moreover, sulfur in the fuel is oxidized during combustion, producing sulfur dioxide and sulfur trioxide, that in presence of water rapidly convert to sulfuric acid, one of the chemical processes that results in acid rain. However, the process for lowering sulfur also reduces the lubricity of the fuel, meaning that additives must be put into the fuel to help lubricate engines. Biodiesel and biodiesel/petrodiesel blends, with their higher lubricity levels, are increasingly being utilized as an alternative. The U.S. annual consumption of diesel fuel in 2006 was about 190 billion litres (42 billion imperial gallons or 50 billion US gallons).^[23]

Chemical composition

Petroleum-derived diesel is composed of about 75% saturated hydrocarbons (primarily paraffins including n, iso, and cycloparaffins), and 25% aromatic hydrocarbons (including naphthalenes and alkylbenzenes).^[24] The average chemical formula for common diesel fuel is C₁₂H₂₃, ranging approximately from C₁₀H₂₀ to C₁₅H₂₈.

Algae, microbes, and water contamination

There has been much discussion and misunderstanding of algae in diesel fuel.^{[25][dead link]} Algae need light to live and grow. As there is no sunlight in a closed fuel tank, no algae can survive, but some microbes can survive and feed on the diesel fuel.

These microbes form a colony that lives at the interface of fuel and water. They grow quite fast in warmer temperatures. They can even grow in cold weather when fuel tank heaters are installed. Parts of the colony can break off and clog the fuel lines and fuel filters.

Water in fuel can damage a fuel injection pump, some diesel fuel filters also trap water.

Road hazard

Petrodiesel spilled on a road will stay there until washed away by sufficiently heavy rain, whereas gasoline will quickly evaporate. After the light fractions have evaporated, a greasy slick is left on the road which can destabilize moving vehicles. Diesel spills severely reduce tire grip and traction, and have been implicated in many accidents. The loss of traction is similar to that encountered on black ice. Diesel slicks are especially dangerous for two-wheeled vehicles such as motorcycles.

Synthetic diesel

Synthetic diesel can be produced from any carbonaceous material, including biomass, biogas, natural gas, coal and many others. The raw material is gasified into synthesis gas, which after purification is converted by the Fischer-Tropsch process to a synthetic diesel.^[26]

The process is typically referred to as biomass-to-liquid (BTL), gas-to-liquid (GTL) or coal-to-liquid (CTL), depending on the raw material used.

Paraffinic synthetic diesel generally has a near-zero content of sulfur and very low aromatics content, reducing unregulated emissions of toxic hydrocarbons, nitrous oxides and PM.^[27]

FAME

Fatty-acid methyl ester (FAME), perhaps more widely known as biodiesel, is obtained from vegetable oil or animal fats (biolipids) which have been transesterified with methanol. It can be produced from many types of oils, the most common being rapeseed oil (rapeseed methyl ester, RME) in Europe and soybean oil (soy methyl ester, SME) in the USA. Methanol can also be replaced with ethanol for the transesterification process, which results in the production of ethyl esters. The transesterification processes use catalysts, such as sodium or potassium hydroxide, to convert vegetable oil and methanol into FAME and the undesirable byproducts glycerine and water, which will need to be removed from the fuel along with methanol traces. FAME can be used pure (B100) in engines where the manufacturer approves such use, but it is more often used as a mix with diesel, BXX where XX is the biodiesel content in percent.^[28][29]

FAME as a fuel is regulated under DIN EN 14214^[30] and ASTM D6751.^[31]

FAME has a lower energy content than diesel due to its oxygen content, and as a result, performance and fuel consumption can be affected. It also can have higher levels of NOx emissions, possibly even exceeding the legal limit. FAME also has lower oxidation stability than diesel, and it offers favorable conditions for bacterial growth, so applications which have a low fuel turnover should not use FAME.^[32] The loss in power when using pure biodiesel is 5 to 7%.^[29]

Fuel equipment manufacturers (FIE) have raised several concerns regarding FAME fuels: free methanol, dissolved and free water, free glycerin, mono and diglycerides, free fatty acids, total solid impurity levels, alkaline metal compounds in solution and oxidation and thermal stability. They have also identified FAME as being the cause of the following problems: corrosion of fuel injection components, low-pressure fuel system blockage, increased dilution and polymerization of engine sump oil, pump seizures due to high fuel viscosity at low temperature, increased injection pressure, elastomeric seal failures and fuel injector spray blockage.^[33]

Unsaturated fatty acids are the source for the lower oxidation stability; they react with oxygen and form peroxides and result in degradation byproducts, which can cause sludge and lacquer in the fuel system.^[34]

As FAME contains low levels of sulfur, the emissions of sulfur oxides and sulfates, major components of acid rain, are low. Use of biodiesel also results in reductions of unburned hydrocarbons, carbon monoxide (CO), and particulate matter. CO emissions using biodiesel are substantially reduced, on the order of 50% compared to most petrodiesel fuels. The exhaust emissions of particulate matter from biodiesel have been found to be 30 percent lower than overall particulate matter emissions from petrodiesel. The exhaust emissions of total hydrocarbons (a contributing factor in the localized formation of smog and ozone) are up to 93 percent lower for biodiesel than diesel fuel.

Biodiesel also may reduce health risks associated with petroleum diesel. Biodiesel emissions showed decreased levels of polycyclic aromatic hydrocarbon (PAH) and nitrited PAH compounds, which have been identified as potential cancer-causing compounds. In recent testing, PAH compounds were reduced by 75 to 85 percent, except for benz(a)anthracene, which was reduced by roughly 50 percent. Targeted nPAH compounds were also reduced dramatically with biodiesel fuel, with 2-nitrofluorene and 1-nitropyrene reduced by 90 percent, and the rest of the nPAH compounds reduced to only trace levels.^[35]

Hydrogenated oils and fats

This category of diesel fuels involves converting the triglycerides in vegetable oil and animal fats into alkanes by refining and hydrogenation. The produced fuel has many properties that are similar to synthetic diesel, and are free from the many disadvantages of FAME.

DME

Dimethyl ether, DME, is a synthetic, gaseous diesel fuel that results in clean combustion with very little soot and reduced NOx emissions.^[36]

Transportation and storage

Diesel fuel is widely used in most types of transportation. The gasoline-powered passenger automobile is the major exception.

Railroad

Diesel displaced coal and fuel oil for steam-powered vehicles in the latter half of the 20th century, and is now used almost exclusively for the combustion engines of self-powered rail vehicles (locomotives and railcars).

Aircraft

The first diesel-powered flight of a fixed-wing aircraft took place on the evening of September 18, 1928, at the Packard Motor Company proving grounds at Utica, USA, with Captain Lionel M. Woolson and Walter Lees at the controls (the first “official” test flight was taken the next morning). The engine was designed for Packard by Woolson, and the aircraft was a Stinson SM1B, X7654. Later that year, Charles Lindbergh flew the same aircraft. In 1929, it was flown 621 miles (999 km) nonstop from Detroit to Langley Field, near Norfolk, Virginia. This aircraft is now owned by Greg Herrick, and is at the Golden Wings Flying Museum near Minneapolis, Minnesota. In 1931, Walter Lees and Fredrick Brossy set the nonstop flight record flying a Bellanca powered by a Packard diesel for 84 hours and 32 minutes. The Hindenburg rigid airship was powered by four 16-cylinder diesel engines, each with approximately 1,200 horsepower (890 kW) available in bursts, and 850 horsepower (630 kW) available for cruising.^{[citation needed]}

The most-produced aviation diesel engine in history has been the Junkers Jumo 205,^{[citation needed]} which, along with its similar developments from the Junkers Motorenwerke, had approximately 1000 examples of the unique opposed piston, two-stroke design power plant built in the 1930s leading into World War II in Germany.

Storage

In the US, diesel is recommended to be stored in a yellow container to differentiate it from kerosene and gasoline, which are typically kept in blue and red containers, respectively.^[37]

Other uses

Poor quality (high sulfur) diesel fuel has been used as an extraction agent for liquid-liquid extraction of palladium from nitric acid mixtures. Such use has been proposed as a means of separating the fission product palladium from PUREX raffinate which comes from used nuclear fuel. In this system of solvent extraction, the hydrocarbons of the diesel act as the diluent while the dialkyl sulfides act as the extractant. This extraction operates by a solvation mechanism. So far, neither a pilot plant nor full scale plant has been constructed to recover palladium, rhodium or ruthenium from nuclear wastes created by the use of nuclear fuel.^[38]

Emissions

See Diesel exhaust.

Taxation

Diesel fuel is very similar to heating oil, which is used in central heating. In Europe, the United States, and Canada, taxes on diesel fuel are higher than on heating oil due to the fuel tax, and in those areas, heating oil is marked with fuel dyes and trace chemicals to prevent and detect tax fraud. Similarly, “untaxed” diesel (sometimes called “off-road diesel”) is available in some countries for use primarily in agricultural applications, such as fuel for tractors, recreational and utility vehicles or other noncommercial vehicles that do not use public roads. Additionally, this fuel may have sulphur levels that exceed the limits for road use in some countries (e.g. USA).

This untaxed diesel is dyed red for identification,^[39] and should a person be found to be using this untaxed diesel fuel for a typically taxed purpose (such as “over-the-road”, or driving use), the user can be fined (e.g. US$10,000 in the USA). In the United Kingdom, Belgium and the Netherlands, it is known as red diesel (or gas oil), and is also used in agricultural vehicles, home heating tanks, refrigeration units on vans/trucks which contain perishable items such as food and medicine and for marine craft. Diesel fuel, or marked gas oil is dyed green in the Republic of Ireland and Norway. The term “diesel-engined road vehicle” (DERV) is used in the UK as a synonym for unmarked road diesel fuel. In India, taxes on diesel fuel are lower than on petrol, as the majority of the transportation for grains and other essential commodities across the country runs on diesel.

In some countries, such as Germany and Belgium, diesel fuel is taxed lower than petrol (gasoline) (typically around 20% lower), but the annual vehicle tax is higher for diesel vehicles than for petrol vehicles.^{[citation needed]} This gives an advantage to vehicles that travel longer distances (which is the case for trucks and utility vehicles) because the annual vehicle tax depends only on engine displacement, not on distance driven. The point at which a diesel vehicle becomes less expensive than a comparable petro vehicle is around 20,000 km a year (12,500 miles per year) for an average car.^{[citation needed]} However, due to a rise in oil prices from about 2009, the advantage point started to drop, causing more people opting to buy a diesel car where they would have opted for a gasoline car a few years ago. Such an increased interest in diesel has resulted in slow but steady “dieseling” of the automobile fleet in the countries affected, sparking concerns in certain authorities about the harmful effects of diesel.^{[citation needed]}

Taxes on biodiesel in the U.S. vary between states; some states (Texas, for example) have no tax on biodiesel and a reduced tax on biodiesel blends equivalent to the amount of biodiesel in the blend, so that B20 fuel is taxed 20% less than pure petrodiesel.^[40] Other states, such as North Carolina, tax biodiesel (in any blended configuration) the same as petrodiesel, although they have introduced new incentives to producers and users of all biofuels.^[41]

See also

Wikimedia Commons has media related to: Diesel fuel

References

External links

• U.S. Department of Labor Occupational Safety & Health Administration: Safety and Health Topics: Diesel Exhaust
• Eight-Year History of Diesel Prices in the U.S.

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Liquefied petroleum gas, also called LPG, GPL, LP Gas, liquid petroleum gas or simply propane, is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. When specifically used as a vehicle fuel it is often referred to as autogas.

Varieties of LPG bought and sold include mixes that are primarily propane (C₃H₈), primarily butane (C₄H₁₀) and, most commonly, mixes including both propane and butane, depending on the season — in winter more propane, in summer more butane^{[citation needed]}. In the United States, primarily only two grades of LPG are sold, commercial propane and HD-5. These specifications are published by the Gas Processors Association (GPA)^[1] and the American Society of Testing and Materials (ASTM)^[2]. Propane/butane blends are also listed in these specifications. Propylene, butylenes and various other hydrocarbons are usually also present in small concentrations. HD-5 limits the amount of propylene that can be placed in LPG, and is utilized as an autogas specification. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The international standard is EN 589. In the United States, tetrahydrothiophene (thiophane) or amyl mercaptan are also approved odorants^[3], although neither is currently being utilized.

LPG is synthesised by refining petroleum or “wet” natural gas, and is almost entirely derived from fossil fuel sources, being manufactured during the refining of petroleum (crude oil), or extracted from petroleum or natural gas streams as they emerge from the ground. It was first produced in 1910 by Dr. Walter Snelling, and the first commercial products appeared in 1912. It currently provides about 3% of all energy consumed, and burns relatively cleanly with no soot and very few sulfur emissions. As it is a gas, it does not pose ground or water pollution hazards, but it can cause air pollution. LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and 43.5 MJ/kg for premium grade petrol (gasoline).^[4] However, its energy density per volume unit of 26 MJ/l is lower than either that of petrol or fuel oil.^{[citation needed]}

LPG evaporates quickly at normal temperatures and pressures and is usually supplied in pressurised steel gas cylinders. They are typically filled to between 80% and 85% of their capacity to allow for thermal expansion of the contained liquid. The ratio between the volumes of the vaporized gas and the liquefied gas varies depending on composition, pressure, and temperature, but is typically around 250:1. The pressure at which LPG becomes liquid, called its vapour pressure, likewise varies depending on composition and temperature; for example, it is approximately 220 kilopascals (2.2 bar) for pure butane at 20 °C (68 °F), and approximately 2.2 megapascals (22 bar) (319 psi) for pure propane at 55 °C (131 °F). LPG is heavier than air, unlike natural gas, and thus will flow along floors and tend to settle in low spots, such as basements. There are two main dangers from this. The first is a possible explosion if the mixture of LPG and air is right and if there is an ignition source. The second is suffocation due to LPG displacing air, causing a decrease in oxygen concentration. Fortunately, LPG is not toxic, so there is no danger of poisoning. In addition, odorants are mixed with all LPG so that leaks can be detected more easily.

Large amounts of LPG can be stored in bulk cylinders and can be buried underground.

Contents 1 Uses 1.1 Rural heating 1.2 Motor fuel 1.3 Refrigeration 1.4 Cooking 2 Security of supply 3 Comparison with natural gas 4 Environmental Effects 5 Fire risk and mitigation 6 See also 7 References 8 External links

Uses

Rural heating

Predominantly in Europe and rural parts of the United States, LPG can provide an alternative to electricity and heating oil (kerosene). LPG is most often used where there is no access to piped natural gas.

LPG can be used as a power source for combined heat and power technologies (CHP). CHP is the process of generating both electrical power and useful heat from a single fuel source. This technology has allowed LPG to be used not just as fuel for heating and cooking, but also for de-centralised generation of electricity.

LPG can be stored in a variety of ways. LPG, as with other fossil fuels, can be combined with renewable power sources to provide greater reliability while still achieving some reduction in CO₂ emissions.

Motor fuel

When LPG is used to fuel internal combustion engines, it is often referred to as autogas or auto propane. In some countries, it has been used since the 1940s as a petrol alternative for spark ignition engines. Two recent studies have examined LPG-fuel-oil fuel mixes and found that smoke emissions and fuel consumption are reduced but hydrocarbon emissions are increased.^[5][6] The studies were split on CO emissions, with one finding significant increases,^[5] and the other finding slight increases at low engine load but a considerable decrease at high engine load.^[6] Its advantage is that it is non-toxic, non-corrosive and free of tetra-ethyl lead or any additives, and has a high octane rating (102-108 RON depending on local specifications). It burns more cleanly than petrol or fuel-oil and is especially free of the particulates from the latter.

LPG has a lower energy density than either petrol or fuel-oil, so the equivalent fuel consumption is higher. Many governments impose less tax on LPG than on petrol or fuel-oil, which helps offset the greater consumption of LPG than of petrol or fuel-oil. However, in many European countries this tax break is often compensated by a much higher annual road tax on cars using LPG than on cars using petrol or fuel-oil. Propane is the third most widely used motor fuel in the world. 2008 estimates are that over 13 million vehicles are fueled by propane gas worldwide. Over 20 million tonnes (over 7 billion US gallons) are used annually as a vehicle fuel.

Not all automobile engines are suitable for use with LPG as a fuel. LPG provides less upper cylinder lubrication than petrol or diesel, as a consequence LPG fueled engines are more prone to wearing valves if not suitably modified. Many modern common rail diesel engines respond well to LPG use as a supplementary fuel. This is where LPG is used as fuel as well as diesel. Systems are now available that integrate with OEM engine management systems.

Refrigeration

LPG is instrumental in providing off-the-grid refrigeration, usually by means of a gas absorption refrigerator.

Blended of pure, dry propane (refrigerant designator R-290 ) and isobutane (R-600a) the blend – “R-290a” – has negligible ozone depletion potential and very low global warming potential and can serve as a functional replacement for R-12, R-22, R-134a,and other chlorofluorocarbon or hydrofluorocarbon refrigerants in conventional stationary refrigeration and air conditioning systems.^[7]

Such substitution is widely prohibited or discouraged in motor vehicle air conditioning systems, on the grounds that using flammable hydrocarbons in systems originally designed to carry non-flammable refrigerant presents a significant risk of fire or explosion.^{[8][9][10][11][12][13][14][15]}

Vendors and advocates of hydrocarbon refrigerants argue against such bans on the grounds that there have been very few such incidents relative to the number of vehicle air conditioning systems filled with hydrocarbons.^[16][17] One particular test was conducted by a professor at the University of New South Wales that unintentionally tested the worst case scenario of a sudden and complete refrigerant loss into the passenger compartment followed by subsequent ignition. He and several others in the car sustained minor burns to their face, ears, and hands, and several observers received lacerations from the burst glass of the front passenger window. No one was seriously injured.^[18]

Cooking

According to the 2001 Census of India, 17.5% of Indian households or 33.6 million Indian households used LPG as cooking fuel in 2001, which is supplied to their homes by Indian Oil which is known as Indane.^[19] 76.64% of such households were from urban India making up 48% of urban Indian households as compared to a usage of 5.7% only in rural Indian households. LPG is subsidised by the government. Increase in LPG prices has been a politically sensitive matter in India as it potentially affects the urban middle class voting pattern.

LPG was once a popular cooking fuel in Hong Kong; however, the continued expansion of town gas to buildings has reduced LPG usage to less than 24% of residential units.

LPG is the most common cooking fuel in Brazilian urban areas, being used in virtually all households. Poor families receive a government grant (“Vale Gás”) used exclusively for the acquisition of LPG.

Security of supply

Because of the natural gas and the oil-refining industry, Europe is almost self-sufficient in LPG. Europe’s security of supply is further safeguarded by:

• a wide range of sources, both inside and outside Europe;
• a flexible supply chain via water, rail and road with numerous routes and entry points into Europe;

As of early 2008, world reserves of natural gas — from which most LPG is derived — stood at 6,342.411 trillion cubic feet. Added to the LPG derived from cracking crude oil, this amounts to a major energy source that is virtually untapped and has massive potential. Production continues to grow at an average annual rate of 2.2%, virtually assuring that there is no risk of demand outstripping supply for the foreseeable future.^{[citation needed]}

Comparison with natural gas

LPG is composed primarily of propane and butane, while natural gas is composed of the lighter methane and ethane. LPG, vaporised and at atmospheric pressure, has a higher calorific value (94 MJ/m³ equivalent to 26.1kWh/m³) than natural gas (methane) (38 MJ/m³ equivalent to 10.6 kWh/m³), which means that LPG cannot simply be substituted for natural gas. In order to allow the use of the same burner controls and to provide for similar combustion characteristics, LPG can be mixed with air to produce a synthetic natural gas (SNG) that can be easily substituted. LPG/air mixing ratios average 60/40, though this is widely variable based on the gases making up the LPG. The method for determining the mixing ratios is by calculating the Wobbe index of the mix. Gases having the same Wobbe index are held to be interchangeable.

LPG-based SNG is used in emergency backup systems for many public, industrial and military installations, and many utilities use LPG peak shaving plants in times of high demand to make up shortages in natural gas supplied to their distributions systems. LPG-SNG installations are also used during initial gas system introductions, when the distribution infrastructure is in place before gas supplies can be connected. Developing markets in India and China (among others) use LPG-SNG systems to build up customer bases prior to expanding existing natural gas systems.

Environmental Effects

Commercially available LPG is currently derived from fossil fuels. Burning LPG releases CO₂, an important greenhouse gas, contributing to global warming. LPG does, however, release less CO₂ per unit of energy than that of coal or oil. It emits 81% of the CO₂ per kWh produced by oil, 70% of that of coal, and less than 50% of that emitted by coal-generated electricity distributed via the grid.^{[citation needed]} Being a mix of propane and butane, LPG emits less carbon per joule than butane but more carbon per joule than propane.

LPG can be considered to burn more ‘cleanly’ than heavier molecule hydrocarbons, in that it releases very few particulates when burnt.

Fire risk and mitigation

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Since LPG turns gaseous under ambient temperature and pressure, it must be stored in special pressure vessels. If the containers are cylindrical and horizontal, they are referred to as “cigars” or “bullets”, whereas circular ones are “spheres”.

LPG containers that are subjected to fire of sufficient duration and intensity can undergo a boiling liquid expanding vapour explosion (BLEVE). Due to the destructive nature of LPG explosions, the substance is classified as a dangerous good.^[20] This is typically a concern for large refineries and petrochemical plants that maintain very large containers. The remedy is to equip such containers with a measure to provide a fire-resistance rating. Large, spherical LPG containers may have up to a 15 cm steel wall thickness. Ordinarily, they are equipped with an approved pressure relief valve on the top, in the centre. One of the main dangers is that accidental spills of hydrocarbons may ignite and heat an LPG container, which increases its temperature and pressure, following the basic gas laws. The relief valve on the top is designed to vent off excess pressure in order to prevent the rupture of the container itself. Given a fire of sufficient duration and intensity, the pressure being generated by the boiling and expanding gas can exceed the ability of the valve to vent the excess. When that occurs, an overexposed container may rupture violently, launching pieces at high velocity, while the released products can ignite as well, potentially causing catastrophic damage to anything nearby, including other containers. In the case of “cigars”, a midway rupture may send two “rockets” going off each way, with plenty of fuel in each to propel each segment at high speed until the fuel is spent.

Mitigation measures include separating LPG containers from potential sources of fire. In the case of rail transport, for instance, LPG containers can be staggered, so that other goods are put in between them. This is not always done, but it does represent a low-cost remedy to the problem. LPG rail cars are easy to spot from the relief valves on top, typically with railings all around.

In the case of new LPG containers, one may simply bury them, only leaving valves and armatures exposed, for easy maintenance. Great care must be taken there though, as mechanical damage can occur to the primers, which can result in hazardous corrosion of the containers. For the buried container, only the exposed parts need to be treated with approved fireproofing materials, such as intumescent and or endothermic coatings, or even fireproofing plasters. The rest are amply protected by soil. Speciality removable covers exist for easy access to the dials and components that must be accessed for proper maintenance and operation of the equipment. LPG containers are subject to significant motion due to expansion, contraction, filling and emptying; even with very thick steel walls. This operational motion makes the burial option less attractive in the long run, because it is difficult to detect mechanical damage to the outer waterproofing of the vessel through soil. A small stone scraping back and forth across the epoxy-painted hull can jeopardise the waterproofing and be the cause for corrosion.

Whilst one may calculate and justify on paper the use of inorganic plasters to cover entire spheres, it can be difficult to keep plasters operable for extended periods of time. Major errors have also been made in the past in this field, as the presumption was that the steel substrate would be adequately protected from rusting through the use of alkaline plasters. The alkalinity in such plasters is due to the presence of cement stone. This alkalinity, however, does not typically have a permanent character, which means that waterproofing with high quality epoxy primers is very important. Also, exterior waterproofing of the plaster is required by some fireproofing plaster vendors, as reduced alkalinity in exposed plasters can have a deleterious effect on the cement stone, which binds the plaster in the first place. By contrast, the intumescent and endothermic coatings are usually epoxy based to begin with, meaning that corrosion of the substrate is no problem whatsoever.

Fireproofing, not unlike all passive fire protection products, is subject to stringent Listing and approval use and compliance. The problem with this is though, that exterior structures of this nature are not subject to the building code or the fire code, meaning that one still sees the majority of LPG containers without any fireproofing at all, as there are often no local regulations, let alone any Authority Having Jurisdiction, apart from an insurance inspector, to force owners to use the proper mitigation methods. Insurance companies are also in a competitive quandary, where such items are concerned, as they compete not only on the basis of rates, but also on the strictness of the demands by their inspectors. LPG vessel fireproofing tests are varied. The only realistic exposure offered is done at the Braunschweig test facility of “BAM” Berlin. BAM’s procedure is to expose a small LPG container to the hydrocarbon test curve and to quantify the results. North American methods are based on UL1709. While UL1709 uses the correct time/temperature curve for testing, it is limited to testing steel columns (not even beams), whereas BAM actually exposes a real LPG container that has been fireproofed. No matter the fireproofing method one uses, it is very important to pay close attention to listing and approval use and compliance and to be sure that the product one chooses has undergone product certification, whereby the original test included the environmental exposures that the product will be exposed to during operations. Particularly with organic products, such as the endothermic and intumescent ones, one must closely review the ageing criteria and be able to quantify how long the product is expected to be operable for. This is where UL1709 “shines”. Anything that can withstand the full battery of environmental exposures prior to the actual fire test, is a very tough product indeed. The idea is to rule out conditions that may render the product inoperable before it is ever exposed to a fire. By using products that have received the appropriate environmental tests FIRST, and the fire expose afterwards, using the very same test sample with all the applicable exposures, one can then demonstrate due diligence, but not otherwise. Likewise, the DIBt ageing qualifications for intumescents have proven to be very reliable. With close attention to the bounding and coverage of ageing and environmental exposures, it is absolutely possible to buy a lot of time for firefighting measures to relieve the LPG containers of the energy exposure from accidental fires and thus reduce the likelihood of a BLEVE to the maximum possible extent.

In June 2009, a freight train carrying LPG derailed in the rail station of Viareggio, Italy. 29 people were killed and over 30 people were injured.

See also

• Listing and approval use and compliance
• Blau gas
• Compressed natural gas (CNG)
• Endothermic
• Filling Carousel
• Fireproofing
• Fire-resistance rating
• Gasoline gallon equivalent
• Hybrid vehicles and Hybrid electric vehicles
• Intumescent
• Industrial gas
• Liquefied natural gas (LNG)
• Natural gas
• Passive fire protection
• Product certification
• Underwriters Laboratories
• World LP Gas Association
• List of CO2 emitted per million Btu of energy from various fuels

References

External links

• WLPGA World LP Gas Association
• PERC Propane Education & Research Council
• NPGA National Propane Gas Association, USA
• Propane 101 Explaining propane and LP Gas fundamentals

Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.

Autogas is widely used as a “green” fuel as it decreases exhaust emissions. In particular, it reduces CO₂ emissions by around 35% compared to petrol. One litre of petrol produces 2.3 kg of CO₂ when burnt, whereas the equivalent amount of autogas produces only 1.5 kg of CO₂ when burnt.^[1] It has an octane rating (MON/RON) that is between 90 and 110 and an energy content (higher heating value—HHV) that is between 25.5 megajoules per litre (for pure propane) and 28.7 megajoules per litre (for pure butane) depending upon the actual fuel composition.

Autogas is the third most popular automotive fuel in the world, with approximately 16 million of 600 million passenger cars powered using the fuel, representing less than 3% of the total market share. Approximately half of all autogas-fueled passenger vehicles are in the five largest markets (in ascending order): Turkey, South Korea, Poland, Italy, and Australia.^[2]

Contents 1 Terminology variations 2 Vehicle manufacturers 3 Countries 3.1 Algeria 3.2 Australia 3.3 Belgium 3.4 Bulgaria 3.5 Canada 3.6 China 3.7 Croatia 3.8 Czech Republic 3.9 Denmark 3.10 France 3.11 Hong Kong 3.12 Italy 3.13 Malta 3.14 Japan 3.15 Netherlands 3.16 Poland 3.17 Russia 3.18 Turkey 3.19 United Kingdom 3.20 United States 4 System types 5 System components 5.1 Filler 5.2 Hoses, pipes and fittings 5.3 Tank 5.4 Valves 5.5 Converter 5.6 Mixer 5.7 Vapour phase injectors 5.8 Liquid phase injectors 5.9 Electrical and electronic controls 5.10 Optional valve protection 6 Converter-and-mixer system operation 7 LPG injection for diesel vehicles 8 See also 9 References 10 External links

Terminology variations

In countries where petrol is called petrol rather than gasoline, it is common for autogas to be simply referred to as gas.^{[citation needed]} This can be confusing for people from countries where petrol is called gasoline, as they often use gas as an abbreviation of gasoline.

In the United States, autogas is more commonly known under the name of its primary constituent, propane. The term autogas is used in the United States to refer to automobile petrol, when used in piston-powered small aircraft. Aircraft owners using this fuel in place of the more common aviation fuel or avgas, require a Supplemental Type Certificate issued by the United States Federal Aviation Agency.

In the UK and Australia LPG and autogas are used interchangeably. In Italy and France, GPL (an acronym for gas di petrolio liquefatto and gaz de pétrole liquéfié) is used, and in Spain GLP (gas licuado del petróleo) is used.

In Asian countries, particularly those with historical American influences such as the Philippines, the term autogas is not commonly recognised as a generic term and the use of the terms LPG or autoLPG is more widely used by consumers, especially by taxi drivers many of whom use converted vehicles.^[3] The converted vehicles are commonly called LPG vehicles or LPG cars.

Vehicle manufacturers

Toyota made a number of LPG-only engines in their 1970s M, R, and Y engine families.

A number of automobile manufacturers—Citroën, Fiat, Ford, Hyundai, General Motors (including Daewoo, Holden, Opel/Vauxhall, Saab), Maruti Suzuki, Peugeot, Renault (including Dacia), Skoda, Tata Motors, Toyota, Volvo, and more recently Volkswagen —have OEM bi-fuel models that will run equally well on both LPG and petrol. Holden Special Vehicles (HSV) also offer bi-fuel models however the vehicles use a different system to that of their donor vehicles from Holden, with HSV using technology from Orbital Autogas Systems, which injects the autogas into the engine as a liquid instead of a gas for increased efficiency.^[4]

Petrol engined cars which have not been fitted with LPG/autogas systems by the manufacturers can usually accept third party systems to enable them to use both LPG or petrol.

Vialle manufacture OEM LPG powered scooters and LPG powered mopeds that run equally well on LPG. Ford Australia have offered an LPG-only variant of their Falcon model since 2000.

• 

  4.0 litre E-Gas straight-six engine of a 2001 Ford AU Falcon.

• 

  3.6 litre Alloytec bi-fuel (petrol and LPG) V6 engine of a 2006–2008 Holden VE Commodore.

Countries

Autogas enjoys great popularity in numerous countries and territories, including Australia, Croatia, Lithuania, the European Union, Hong Kong, India, Philippines, the Republic of Macedonia, South Korea, Serbia, and Turkey. It is also available at larger petrol stations in several countries. In the Republic of Armenia, for example, the transport ministry estimates as many as 20 to 30% of vehicles use autogas, because it offers a very cheap alternative to both diesel and petrol, being less than half the price of petrol and some 40% cheaper than diesel. The recent^[when?] rises in oil-derived fuel prices has significantly increased the difference.

Algeria

Since the 1980s, the Algerian Government has pursued a policy to promote the use of autogas in Algeria. The two main incentives for the government to put this policy into action was to take advantage of the large LPG production and reduce urban pollution. At the end of 2003, there were approximately 120,000 autogas-powered vehicles on the roads, supported by over 300 refuelling stations, accounting for 14% of the national vehicle fuel network.^[5]

The Algerian Government fixes the prices of all automotive fuels. Autogas is priced in Algeria at 61% of the price of diesel, making it an affordable option.^[5]

Australia

LPG is popular in Australia, because it is less than half the price of petrol in urban areas (approx A$0.59-0.75 per litre, as opposed to A$1.10-1.35 per litre for unleaded fuel and A$1.15-1.30 per litre for diesel, as of February 2010), and it is locally produced. The three major local manufacturers, (Ford, Holden and Toyota), offer factory fitted autogas in some models of their locally made large cars and commercial vehicles. Mitsubishi Australia formerly manufactured factory-fitted autogas vehicles locally but ceased manufacturing in 2008. All factory autogas vehicles, with the exception of the E-Gas Ford Falcon model, are bi-fuel vehicles, meaning they have the capability to run on either petrol, autogas, or a combination.^[6] It should be noted that Holden Special Vehicles offers a different autogas system to its parent, Holden, that injects the autogas into the engine as a liquid, making for efficiency.^[7]

There are over 615,000 autogas-powered cars on Australia’s roads and over 3,200 refuelling stations.^[8] Autogas is especially popular with taxis, except in remote areas where transportation costs make autogas prices uncompetitive.

Whilst autogas is currently excise-free, excise is to be imposed on all vehicle fuels that are not currently subject to excise, being added incrementally from 2011 to 2015. The excise on autogas will start at 2.5 cents per litre in 2011 and reach 12.5 cents per litre by 2015. By comparison, the excise on petrol will remain at its existing 38 cents per litre. The additional excise on autogas is being offset somewhat by a subsidy that was implemented in 2006 for private motorists, paying either A$2000 to convert their existing vehicle to autogas, or A$1000 for purchasing a new vehicle that was manufactured to operate on autogas.^[9] The subsidy does not apply to business vehicles or vehicles with a Gross Vehicle Mass of over 3500 kilograms. In addition to the subsidy provided by the Australian federal government, the Western Australian government also provides a A$1000 subsidy under the long-running LPG subsidy scheme.

Belgium

The use of autogas was once very popular in Belgium, thanks to the subsidies given by the government to install conversion kits. Since, 2003, when the subisidies disappeared, the number of cars running in LPG has decreased and the number of cars running on diesel has increased. In recent years, the use of autogas as a vehicle fuel has accounted for less than 2% of vehicle fuel use in Belgium. At the end of 2003, there were an estimated 93,000 autogas-powered vehicles on Belgium, supported by 600 refuelling stations.^[5] The price of a litre of autogas is approximately 50% of the price of diesel, thanks to the low taxation on autogas by the Belgian government.

Bulgaria

Autogas consumption in Bulgaria accounted for 14% the total fuel consumption in 2003, an amount which has tripled since 1999. By the end of 2003, there were an estimated 195,000 autogas-powered vehicles on the road, with around 1,500 refuelling stations. Autogas is also very popular with commercial users in Bulgaria, as 90% of minibuses and taxicabs were able to run on the fuel. Vehicles originally manufactured to operate on autogas are virtually non-existent in Bulgaria, so the vast majority of the vehicles are third-party conversions.^[5]

Canada

In 2003, there were an estimated 92,000 autogas vehicles on Canada’s roads, accounting for 0.8% or the total automotive fuel use. In the late 1980s and early 1990s, autogas enjoyed widespread consumption in Canada, only to decline in the late 1990s.^[5]

In the early 1980s, there were few autogas vehicles in Canada. Then, the Canadian Government established a grant to convert petrol vehicles to run on alternative fuels, in an attempt to resolve or improve the country’s energy security concerns. The grant was a success, with Autogas becoming Canada’s most popular alternative vehicle fuel by a wide margin. Over 5,000 refuelling stations were set up to facilitate the boom, and autogas sales peaked with in 1992 700,000 tonnes sold. In the mid 1990s, the national conversion grant was dropped and components became more expensive. This resulted in a major decline in autogas sales and vehicles by more than half, with only 310,000 tonnes sold in 2003, equal to 0.8% of the total automotive fuel consumption. In 2005, an estimated 92,000 autogas vehicles survived on Canada’s roads, with the majority being owned by commercial users. Many of the previous autogas users have since switched to diesel or CNG.

China

Autogas consumption in China has grown rapidly since the 1990s, has slowed down in the early 2000s, but has started to grow again in recent years. In 2009, Autogas refuelling stations have spread to 25 cities and has become a major alternative fuel in China. Motorcycles account for a large portion of the autogas, with over 260,000 Autogas motorcycles in Shanghai alone. In Shenyang, the local government is encouraging public transport to convert to autogas, and as of 2009 over 160,000 taxicabs run on the fuel as well as over 2,500 buses. The city of Guangzhou accounted for 46.56% of national autogas consumption in 2009. Only 24% of China’s Liquefied Petroleum Gas is produced domestically.^[5][10]

Croatia

As of 2008, approximately 30,000 Croatians drove using autogas, which at the time was available from 90 stations throughout the nation. In 2009, it was estimated that there were 60,000 autogas-powered cars on Croatia‘s roads,^[11] and in 2010, it is estimated that 150,000 drivers in Croatia were using the autogas. This recent increase in popularity has largely been attributed to the lower price of autogas compared to petrol or diesel.^[12]

In 2009, Croatia exported 51% of domestically produced Liquefied Petroleum Gas (LPG), leaving only 49% for consumption. Out of that 49%, 45% of domestically sold LPG is used as autogas. Damir Stambuk from the Croatian Ministry of Economy, which is also responsible for energy, said that Croatia is not yet ready for a regular autogas market due to a small network of stations, but in the future it will be.^[13]

Czech Republic

At the end of 2003, the roads of the Czech Republic had an estimated 145,000 autogas vehicles with 350 refuelling stations.^[5]

Denmark

Autogas is uncommon in Denmark, and as a result there are only around 13 refuelling stations. The stations are run by Shell, YX, OK, Uno-X, Q8 and Statoil.^[14]

France

It was estimated that France would have over 62,500 autogas vehicles on the road by the end of 2010.^[15] By the end of 2003, there were an estimated 190,000 autogas vehicles in use with almost 1,900 refuelling stations. In 2005, autogas accounted for around 0.4% of the total automotive fuel use.^[5]

Hong Kong

In Hong Kong all taxicabs rely on autogas. Many public light buses also rely on autogas.

Italy

Autogas is very popular in Italy. With over 1,000,000 autogas vehicles on the road,^[16] it is the second largest autogas market in the European Union, after Poland. Italy was one of the first countries in the world to introduce autogas, which happened in the 1950s.^[5] In the first half of 2010 alone, more than 170,000 new autogas cars were registered.^[17] General Motors has been especially successful in Italy, with two-thirds of the vehicles sold in 2008 being autogas-capable.^[18]

Malta

Autogas was introduced to Malta on 22 May 2012 by Liquigas. The first filling station is located at the Malta International Airport.

Japan

Currently, Japan has about 280,000 autogas vehicles on the road, which is less than in recent years. However, the number of autogas vehicles on Japan’s roads has been very unstable. The first autogas taxicabs were introduced in Japan in the 1960s/1970s. With a sharp decline in the 1990s, the number started to rise again in 2003. Sometime between 2004 and 2010, the number has dropped. The vast majority of autogas vehicles on Japanese roads are taxicabs or commercial vehicles.^[5] This is why, in 2010, the Japan LP Gas Association started an initiative to encourage corporations and motorists alike to switch to autogas vehicles. The initiative involves 27,000 Japanese retailers to introduce an autogas vehicle into their fleet every three years. Many of these corporations already have autogas vehicles, but Makoto Arahata from the Japanese LP Gas Association says that there is still much room for improvement.^[19]

Netherlands

Use of autogas has varied in the Netherlands. It went up in the 1980s and has gone down ever since, except for an increase in 2005.^[20] In 2010, there are around 220,000 autogas vehicles on the road (total cars being a little less than 8 million).^[21]

Autogas is so ubiquitous, there are very few fuel stations that do not have it. The aptly named Dutch Bayonet is the standard filling device used.

The road tax on autogas vehicles can be up to 2 times that of petrol powered vehicles. On the modern G3 autogas systems, the difference on tax is zero for cars up to 850 kg, but increases for heavier cars.^[22] (Compare the diesel tax, which is twice the petrol tax.) But because the price of autogas is less than half that of petrol, retrofitting a car with an autogas tank is economically viable after around 10,000 km/year.

Poland

Poland is one of the oldest and most successful markets in Europe. In 2011, there were 6050 autogas refuelling stations and 2,500,000 autogas vehicles on the road. The number of autogas vehicles in Poland increased by 8% in 2011, however autogas sales decreased by 3.7%. This is mostly due to older vehicles being replaced with newer, more fuel efficient ones. Almost half of Poland’s LPG comes from Russia.^[23] As of 2011, the number of autogas vehicles exceeded 2,500,000.^[24]

Russia

Autogas is widely used in Russia. In its modern form it has been used since the 1970s. There are two types of autogas equipment and autogas stations as well. These are LPG (propane-butane mix) and Pressurised Gas (methane). The main consumer of LPG is commercial transport. Pressurised Gas is losing its positions to LPG and now can be rarely seen on public transport buses.^{[citation needed]}. There are some community supported sources where people post gas station location on the map. gas station on a map. Gaz station on a map 2 (propane) / gas stations on a map 2 (metane). These sources may be used by some travelers going to Russia by car. First limited series of vehicles driven by multifuel including metane has appeared in the middle of 20-th century

Turkey

Turkey has the highest percentage of autogas vehicles in the world. Some 37% of passenger cars run on autogas and autogas consumption now exceeds gasoline consumption. The Turkish government regulated the autogas price to provide consumers with a net economic advantage of 20-35%. As of the end of 2010, there are 8,500 autogas fueling stations around the country and market growth has been supported by a network of 1,000 licensed conversion shops.^[25]

According to Turkish Statistics Institute’s—TUIK, a governmental organisation— the nation has over 16,500,000 vehicles in January, 2012. %50.3 are passenger vehicles. 16.2% light weight trucks, 15.7% motorcycles, %9.2 tractors, 4.6% heavy weight trucks, 2.5% mini buses for transportation, 1.4% buses and %0.1 special purpose vehicles.

Right now monthly, average 50.000 new generation cars are sold.

LPG is dominantly used in Turkey as an autogas while CNG converted vehicles is only around 500 cars and there is only 2 CNG filling stations.

In Turkey, nobody has the courage to convert diesel vehicles to LPG after unsucessul applications in the past. For that reason, the conversion workshops don’t make installations to light and heavy weight trucks, tractors, bus and mini-buses and motorcycles.

8,3 millions are passenger vehicles. 33% of the passenger cars (2,739.000 ) are diesel powered and 67% are gasoline powered (5.561.000). As there is no conversion to diesel cars, among 5.561.000 gasoline powered passenger cars, According to the reports of MMO ( Chamber of Mechanical Engineer’s Department autohorised to deal with the leakage tests and exhause emissions of LPG powered vehicles) declared that LPG powered vehciles are 3.1 million by the end of 2011.

This means more than 55% of gasoline powered passenger vehicles are already converted to LPG.

The converted vehicles were mostly carburated engines. More or less 90% of the old carburated engines has already been converted and day by day, new generation vehicle owners are also choosing LPG as an alternative fuel.

The reason of this high LPG application is because of the Turkish government’s application of an unbelaivable high fuel taxes + OTV (special consumption tax) especially upon the petrol and diesel prices and due to that reason Turkish people are using the most expensive fuel in the world for almost 50 years. (Even though Turkey has borders with OPEC countries exporting crude oil and petroleum to the world and has the lowest transportation costs ) Turkish people found the only solution to save money from their road expenses by converting their cars to autogas which gives them an advantage of 35% up to 40% saving.

This big conversion is the success of Turkish Autogas Kits and Autogas Tanks manufacturers starting from 1995, even though autogas use became legal in 2000. At the same time, Italian companies also supplied systems through their several companies.

United Kingdom

According to the LPG trade association ^[26] in the UK there are about 1500 refuelling stations that cater for the 160,000 LPG powered vehicles on UK roads. This represents less than 1% of vehicles. The only Government incentive to use LPG is the lower road fuel tax applied to LPG compared to petrol. As of January 2012, the saving of about 60 pence per litre is the highest it has ever been and that combined with conversion prices being an historic low should result in an increase in LPG conversions. Technology has reached the point where almost all conversions are ‘Sequential Vapour Injection’, and in the UK there is a large number of kits ^{[27][better source needed]} with various price and quality ranges to choose from, resulting in a very competitive market.

United States

Autogas is on the rise in the United States. As of February 2012,^[28] the United States has more than 270,000 autogas vehicles on the road, accounting for just 2% of the world’s total and as of 2011, the United States has more than 2,600 autogas fueling stations, making it easier for drivers to refuel across the country.^[29] The U.S. Department of Energy has a website that autogas drivers can easily locate autogas fueling stations near them as well as other alternative fuels.^[30] The cost of converting a car to use gasoline or autogas at a turn of a knob starts from US$3,000.^[31] Autogas use by car drivers can help the United States to reduce dependence on foreign oil as 90% of all U.S. Autogas is produced in the U.S.^[32][33] In 2005, a provision was enacted that placed a 50 cent per gallon tax credit on propane autogas as part of H.R. 4853, making it $1 per gallon cheaper than petrol on average. The alternative fuel credit was extended in 2010 and remains in effect until the end of 2011.

Autogas for America claims to be the unified voice of the autogas industry in the United States. Composed of autogas experts, transportation industry specialists and environmental advocates, Autogas for America says it “leverages industry cooperation to widen recognition of autogas among the US public, media and government.”^[34]

System types

The different autogas systems generally use the same type of filler, tanks, lines and fittings but use different components in the engine bay. Liquid injection systems use special tanks with circulation pumps and return lines similar to petrol fuel injection systems.

There are three basic types of autogas system. The oldest of these is the conventional converter-and-mixer system, which has existed since the 1940s and is still widely used today. The other two types are known as injection systems, but there are significant differences between the two.

A converter-mixer system uses a converter to change liquid fuel from the tank into vapour, then feeds that vapour to the mixer where it is mixed with the intake air. This is also known as a venturi system or “single point” system.

Vapour phase injection systems also use a converter, but unlike the mixer system, the gas exits the converter at a regulated pressure. The gas is then injected into the air intake manifold via a series of electrically controlled injectors. The injector opening times are controlled by the autogas control unit. This unit works in much the same way as a petrol fuel injection control unit. This allows much more accurate metering of fuel to the engine than is possible with mixers, improving economy and/or power while reducing emissions. Liquid phase injection systems do not use a converter, but instead deliver the liquid fuel into a fuel rail in much the same manner as a petrol injection system. These systems are still very much in their infancy. Because the fuel vaporises in the intake, the air around it is cooled significantly. This increases the density of the intake air and can potentially lead to substantial increases in engine power output, to the extent that such systems are usually de-tuned to avoid damaging other parts of the engine. Liquid phase injection has the potential to achieve much better economy and power plus lower emission levels than are possible using mixers or vapour phase injectors.

System components

Filler

The fuel is transferred into a vehicle tank as liquid by connecting the bowser at the filling station to the filler fitting on the vehicle.

The type of filler used varies from country to country and in some cases different types are used within the same country.^[35]

The three types are:

• ACME thread. This type has a threaded fitting onto which the bowser nozzle is screwed before the trigger is pulled to establish a seal before fuel transfer. This type is used in Australia, USA, Germany, Austria, Belgium, Republic of Ireland.
• ‘Dutch’ Bayonet. This type establishes a gas proof seal by a push and twist action. This type is used in the United Kingdom, Netherlands and Switzerland.
• ‘Italian’ Dish. This type is used in Italy, France, Poland, Scandinavia and Portugal.

Adaptors that allow a vehicle fitted with a particular system to refuel at a station equipped with another system are available.

The fill valve contains a check valve so that the liquid in the line between the filler and the tank(s) does not escape when the bowser nozzle is disconnected.

In installations where more than one tank is fitted, T-fittings may be used to connect the tanks to one filler so that the tanks are filled simultaneously. In some applications, more than one filler may be fitted, such as on opposite sides of the vehicle. These may be connected to separate tanks, or may be connected to the same tanks using T-fittings in the same manner as for connecting multiple tanks to one filler.

Fillers are typically made of brass to avoid the possibility of sparks when attaching or removing the bowser that might occur if steel fittings were used.

Hoses, pipes and fittings

The hose between the filler and tank(s) is called the fill hose or fill line. The hose or pipe between the tank(s) and the converter is called the service line. These both carry liquid under pressure.

The flexible hose between the converter and mixer is called the vapour hose or vapour line. This line carries vapour at low pressure and has a much larger diameter to suit.

Where the tank valves are located inside an enclosed space such as the boot of a sedan, a plastic containment hose is used to provide a gas-tight seal between the gas components and the inside of the vehicle.

Liquid hoses for LPG are specifically designed and rated for the pressures that exist in LPG systems, and are made from materials designed to be compatible with the fuel. Some hoses are made with crimped fittings, while others are made using re-usable fittings that are pressed or screwed onto the end of the hose.

Rigid sections of liquid line are usually made using copper tubing, although in some applications, steel pipes are used instead. The ends of the pipes are always double-flared and fitted with flare nuts to secure them to the fittings.

Liquid line fittings are mostly made from brass. The fittings typically adapt from a thread in a component, such as a BSP or NPT threaded hole on a tank, to an SAE flare fitting to suit the ends of pipes or hoses.

Tank

Further information: Gas tank, Gas cylinder, Storage tank, and Pressure vessel

Vehicles are often fitted with only one tank, but multiple tanks are used in a some applications. In passenger car applications, the tank is typically either a cylindrical tank mounted in the boot of the vehicle or a toroidal tank or set of permanently interconnected cylinders placed in the spare wheel well. In commercial vehicle applications, the tanks are generally cylindrical tanks mounted either in the cargo space or on the chassis underneath the body.

The tanks have fittings for filling, liquid outlet, emergency relief of excess pressure, fuel level gauge and sometimes a vapour outlet. These may be separate valves mounted into a series of 3 to 5 holes in a plate welded into the tank shell, or may be assembled onto a multi-valve unit which is bolted into one large hole on a boss welded into the tank shell.

Modern fill valves are usually fitted with an automatic fill limiter (AFL) to prevent overfilling. The AFL has a float arm which restricts the flow significantly but does not shut it off entirely. This is intended to cause the pressure in the line to rise enough to tell the bowser to stop pumping but not cause dangerously high pressures. Before AFLs were introduced, it was common for the filler (with integral check valve) to be screwed directly into the tank, as the operator had to open an ullage valve at the tank while filling, allowing vapour out of the top of the tank and stopping filling when liquid started coming out of the ullage valve to indicate that the tank was full. Modern tanks are not fitted with ullage valves.

The liquid outlet is usually used to supply fuel to the engine, and is usually referred to as the service valve. Modern service valves incorporate an electric shut-off solenoid. In applications using very small engines such as small generators, vapour may be withdrawn from the top of the tank instead of liquid from the bottom of the tank.

The emergency pressure relief valve in the tank is called a hydrostatic pressure relief valve. It is designed to open if the pressure in the tank is dangerously high, thus releasing some vapour to the atmosphere to reduce the pressure in the tank. The release of a small quantity of vapour reduces the pressure in the tank, which causes some of the liquid in the tank to vaporise to re-establish equilibrium between liquid and vapour. The latent heat of vaporisation causes the tank to cool, which reduces pressure even further.

The gauge sender is usually a magnetically coupled arrangement, with a float arm inside the tank rotating a magnet, which rotates an external gauge. The external gauge is usually readable directly, and most also incorporate an electronic sender to operate a fuel gauge on the dashboard.

Valves

There are a number of types of valve used in autogas systems. The most common ones are shut-off or filter-lock valves, which are used to stop flow in the service line. These may be operated by vacuum or electricity. On bi-fuel systems with a petrol carburettor, a similar shut-off valve is usually fitted in the petrol line between the pump and carburettor.

Check valves are fitted in the filler and on the fill input to the fuel tank to prevent fuel flowing back the wrong way.

Service valves are fitted to the outlet from the tank to the service line. These have a tap to turn the fuel on and off. The tap is usually only closed when the tank is being worked on. In some countries, an electrical shut-off valve is built into the service valve.

Where multiple tanks are fitted, a combination of check valves and a hydrostatic relief valve are usually installed to prevent fuel from flowing from one tank to another. In Australia, there is a common assembly designed for this purpose. It is a combined twin check valve and hydrostatic relief valve assembly built in the form of a T-fitting, such that the lines from the tanks come into the sides of the valve and the outlet to the converter comes out the end. Because there is only one common brand of these valves, they are known colloquially as a Sherwood valve.

Converter

The converter (also known as vaporiser) is a device designed to change the fuel from a pressurised liquid to a vapour at around atmospheric pressure for delivery to the mixer or vapour phase injectors. Because of the refrigerant characteristic of the fuel, heat must be put into the fuel by the converter. This is usually achieved by having engine coolant circulated through a heat exchanger that transfers heat from that coolant to the LPG.

There are two distinctly different basic types of converter for use with mixer type systems. The European style of converter is a more complex device that incorporates an idle circuit and is designed to be used with a simple fixed venturi mixer. The American style of converter is a simpler design which is intended to be used with a variable venturi mixer that incorporates an idle circuit.

Engines with a low power output such as; scooters, quad bikes and generators can use a simpler type of converter (also known as governor or regulator). These converters are fed with fuel in vapour form. Evaporation takes place in the tank where refrigeration occurs as the liquid fuel boils. The tanks large surface area exposed to the ambient air temperature combined with the low power output (fuel requirement) of the engine make this type of system viable. The refrigeration of the fuel tank is proportional to fuel demand hence this arrangement is only used on smaller engines. This type of converter can either be fed with vapour at tank pressure (called a 2 stage regulator) or be fed via a tank mounted regulator at a fixed reduced pressure (called a single stage regulator).

Mixer

The mixer is the device that mixes the fuel into the air flowing to the engine. The mixer incorporates a venturi designed to draw the fuel into the airflow due to the movement of the air.

Mixer type systems have existed since the 1940s and some designs have changed little over that time. Mixers are now being increasingly superseded by injectors.

Vapour phase injectors

Most vapour phase injection systems mount the solenoids in a manifold block or injector rail, then run hoses to the nozzles, which are screwed into holes drilled and tapped into the runners of the intake manifold. There is usually one nozzle for each cylinder. Some vapour injection systems resemble petrol injection, having separate injectors that fit into the manifold or head in the same manner as petrol injectors, and are fed fuel through a fuel rail.

Liquid phase injectors

Liquid phase injectors are mounted onto the engine in a manner similar to petrol injectors, being mounted directly at the inlet manifold and fed liquid fuel from a fuel rail.

Electrical and electronic controls

There are four distinct electrical systems that may be used in autogas systems – fuel gauge sender, fuel shut-off, closed loop feedback mixture control and injection control.

In some installations, the fuel gauge sender fitted to the autogas tank is matched to the original fuel gauge in the vehicle. In others, an additional gauge is added to display the level of fuel in the autogas tank separately from the existing petrol gauge.

In most modern installations, an electronic device called a tachometric relay or safety switch is used to operate electrical shut-off solenoids. These work by sensing that the engine is running by detecting ignition pulses. Some systems use an engine oil pressure sensor instead. In all installations, there is a filterlock (consisting of a filter assembly and a vacuum or electric solenoid operated shut-off valve) located at the input to the converter. In European converters, there is also a solenoid in the converter to shut off the idle circuit. These valves are usually both connected to the output of the tachometric relay or oil pressure switch. Where solenoids are fitted to the outputs of fuel tanks, these are also connected to the output of the tachometric relay or oil pressure switch. In installations with multiple tanks, a switch or changeover relay may be fitted to allow the driver to select which tank to use fuel from. On bi-fuel, the switch used to change between fuels is used to turn off the tachometric relay.

Closed loop feedback systems use an electronic controller that operates in much the same way as in a petrol fuel injection systems, using an oxygen sensor to effectively measure the air/fuel mixture by measuring the oxygen content of the exhaust and control valve on the converter or in the vapour line to adjust the mixture. Mixer type systems that do not have a closed loop feedback fitted are sometimes referred to as open loop systems.

Injection systems use a computerised control system which is very similar to that used in petrol injection systems. In virtually all systems, the injection control system integrates the tachometric relay and closed loop feedback functions.

Optional valve protection

Many LPG equipment installers recommend the installation of so-called valve protection systems. These can consist in the most simple case of a bottle containing valve protection liquid. The liquid is drawn into the air intake system and distributed into the engines’ cylinders along with the fuel and air.

More sophisticated systems can consist of a piggyback ECU that is synchronised with the LPG injector ECU. This results in a more precise injection of valve protection fluid.^{[citation needed]}

Converter-and-mixer system operation

The designs of converters and mixers are matched to each other by matching sizes and shapes of components within the two.

In almost all over the world the “converter” word is not mostly used. The LPG REGULATOR – REDUCER – or VAPORIZER are more popular.

Because it has 3 main functions:

1- REDUCER : It reduces the high pressure of incoming liquid phase LPG down to atmospheric pressure.

2- REGULATOR : It regulates the gas flow according to the requirement of the engine.

3- VAPORIZER : It evaporizes the liquid form LPG into gas form by using the hot coolant circulation of the engine.

In European style systems, the size and shape of the venturi is designed to match the converter. In American style systems, the air valve and metering pins in the mixer are sized to match the diaphragm size and spring stiffness in the converter. In both cases, the components are matched by the manufacturers and only basic adjustments are needed during installation and tuning.

An autogas carburettor may simply consist of a throttlebody and a mixer, sometimes fitted together using an adapter.

Cold start enrichment is achieved by the fact that the engine coolant is cold when the engine is cold. This causes denser vapour to be delivered to the mixer. As the engine warms up, the coolant temperature rises until the engine is at operating temperature and the mixture has leaned off to the normal running mixture. Depending on the system, the throttle may need to be held open further when the engine is cold in the same manner as with a petrol carburettor. On others, the normal mixture is intended to be somewhat lean and no cold-start throttle increase is needed. Because of the way enrichment is achieved, no additional choke butterfly is required for cold starting with LPG.

The temperature of the engine is critical to the tuning of an autogas system. The engine thermostat effectively controls the temperature of the converter, thus directly affecting the mixture. A faulty thermostat, or a thermostat of the wrong temperature range for the design of the system may not operate correctly.

The power output capacity of a system is limited by the ability of the converter to deliver a stable flow of vapour. A coolant temperature lower than intended will reduce the maximum power output possible, as will an air bubble trapped in the cooling circuit or complete loss of coolant. All converters have a limit, beyond which mixtures become unstable. Unstable mixtures typically contain tiny droplets of liquid fuel that were not heated enough in the converter and will vaporise in the mixer or intake to form an excessively rich mixture. When this occurs, the mixture will become so rich that the engine will flood and stall. Because the outside of the converter will be at or below 0°C when this happens, water vapour from the air will freeze onto the outside of the converter, forming an icy white layer. Some converters are very susceptible to cracking when this happens.

LPG injection for diesel vehicles

LPG may be used for a supplemental fuel for diesels of all sizes. A gallon of diesel contains 128,700 BTU per US gallon, where propane contains 91,690 BTU per US gallon. If LPG is 30-40% less expensive, there may very well be a saving.

Any actual savings are dependent on the relative cost of diesel versus LPG. In Australia, where diesel costs substantially more than LPG, savings of 10 to 20% are claimed.^[36]

The above systems add small quantities of LPG with the primary aim of improving economy, but much larger quantities of LPG can be injected in order to increase power. Even at full output a diesel engine runs about 50% lean of stoichiometric to avoid black smoke production, so there is a substantial amount of oxygen in the intake charge which is not consumed in the combustion process. This oxygen is therefore available for the combustion of a substantial addition of LPG resulting in a large increase in power output.

A successful LPG sequential injection system is being offered by “Solaris Diesel”, a system well suited for large diesel engines in trucks and delivery.

See also

• Hybrid vehicle
• Fuel injection
• Gas engine

which exhaust gas emission is increased when biodiesel is burned as compared to conventional diesel

References

External links

• European LPG Association
• World LP Gas Association
• LPG Information

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