A hydrogen vehicle is a vehicle that uses hydrogen as its onboard fuel for motive power. Hydrogen vehicles include hydrogen fueled space rockets, as well as automobiles and other transportation vehicles. The power plants of such vehicles convert the chemical energy of hydrogen to mechanical energy either by burning hydrogen in an internal combustion engine, or by reacting hydrogen with oxygen in a fuel cell to run electric motors. Widespread use of hydrogen for fueling transportation is a key element of a proposed hydrogen economy.

Hydrogen fuel does not occur naturally on Earth and thus is not an energy source, but is an energy carrier. Currently it is most frequently made from methane or other fossil fuels. However, it can be produced from a wide range of sources (such as wind, solar, or nuclear) that are intermittent, too diffuse or too cumbersome to directly propel vehicles. Integrated wind-to-hydrogen plants, using electrolysis of water, are exploring technologies to deliver costs low enough, and quantities great enough, to compete with traditional energy sources.^[1]

Many companies are working to develop technologies that might efficiently exploit the potential of hydrogen energy for mobile uses. The attraction of using hydrogen as an energy currency is that, if hydrogen is prepared without using fossil fuel inputs, vehicle propulsion would not contribute to carbon dioxide emissions. The drawbacks of hydrogen use are low energy content per unit volume, high tankage weights, very high storage vessel pressures, the storage, transportation and filling of gaseous or liquid hydrogen in vehicles, the large investment in infrastructure that would be required to fuel vehicles, and the inefficiency of production processes.

Contents 1 Vehicles 1.1 Automobiles 1.2 Buses 1.3 Bicycles 1.4 Motorcycles and scooters 1.5 Quads and tractors 1.6 Airplanes 1.7 Fork trucks 1.8 Rockets 2 Internal combustion vehicle 3 Fuel cell 3.1 Fuel cell cost 3.2 Freezing conditions 3.3 Service life 4 Hydrogen 4.1 Production 4.2 Storage 4.3 Infrastructure 4.4 Codes and standards 5 Criticism 6 Comparison with other types of alternative fuel vehicle 6.1 Plug-in hybrids 6.2 Natural gas 6.3 Battery electric vehicles 7 See also 8 References 9 External links

Vehicles

Buses, trains, PHB bicycles, canal boats, cargo bikes, golf carts, motorcycles, wheelchairs, ships, airplanes, submarines, and rockets can already run on hydrogen, in various forms. NASA used hydrogen to launch Space Shuttles into space. A working toy model car runs on solar power, using a regenerative fuel cell to store energy in the form of hydrogen and oxygen gas. It can then convert the fuel back into water to release the solar energy.^[2]

The current land speed record for a hydrogen-powered vehicle is 286.476 mph (461.038 km/h) set by Ohio State University‘s Buckeye Bullet 2, which achieved a “flying-mile” speed of 280.007 mph (450.628 km/h) at the Bonneville Salt Flats in August 2008. For production-style vehicles, the current record for a hydrogen-powered vehicle is 333.38 km/h (207.2 mph) set by a prototype Ford Fusion Hydrogen 999 Fuel Cell Race Car at Bonneville Salt Flats in Wendover, Utah in August 2007. It was accompanied by a large compressed oxygen tank to increase power. Honda has also created a concept called the FC Sport that it hopes will challenge that record.^[3]

Automobiles

Many companies are currently researching the feasibility of building hydrogen cars, and some automobile manufacturers have begun developing hydrogen cars (see list of fuel cell vehicles). Funding has come from both private and government sources. However, the Ford Motor Company has dropped its plans to develop hydrogen cars, stating that “The next major step in Ford’s plan is to increase over time the volume of electrified vehicles”.^[4] Similarly, French Renault-Nissan announced in 2009 that it is cancelling its hydrogen car R&D efforts.^[5] As of October 2009, General Motors CEO Fritz Henderson noted that GM had reduced its hydrogen program because the cost of building hydrogen cars was too high. “It’s still a ways away from commercialization”, he said. The “Volt will likely cost around $40,000 while a hydrogen vehicle would cost around $400,000.^[6] Most hydrogen cars are currently only available as demonstration models for lease in limited numbers and are not yet ready for general public use. The estimated number of hydrogen-powered cars in the United States was 200 as of October 2009, mostly in California.^[7]

Honda introduced its first fuel cell vehicle in 1999 called the FCX and has since then introduced the second generation FCX Clarity. In 2007 at the Greater Los Angeles Auto Show, Honda unveiled the first production model of the FCX Clarity. Limited marketing of the FCX Clarity began in June 2008 in the United States, and it was introduced in Japan in November 2008.^[8] The FCX Clarity is available in the U.S. only in Los Angeles Area, where 16 hydrogen filling stations are available, and as of July 2009, ten drivers had leased the Clarity for US$600 a month.^[9] Honda stated that it could start mass producing vehicles based on the FCX concept by the year 2020^[9] and reaffirmed, in 2009, that it continues to put resources into hydrogen fuel cell development, which it saw as “a better long term bet than batteries and plug-in vehicles”.^[10] In December 2010, however, it introduced a BEV version of the Honda Fit, using elements of its hydrogen engine design, stating that the “industry trend seems to be focused on the battery electric vehicle”.^[11]

In 2011, Hyundai revealed its Blue² (“Blue Square”) fuel cell electric vehicle (FCEV), and stated that it plans to have FCEVs available for sale by 2014.^[12] In early 2009, Daimler announced plans to begin its FC vehicle production in 2009 with the aim of 100,000 vehicles in 2012–2013.^[13][14] In 2009, Nissan started testing a new FC vehicle in Japan.^[15] In September 2009, Daimler, Ford, General Motors, Honda, Hyundai, Kia, Renault, Nissan and Toyota issued a joint statement about their undertaking to further develop and launch fuel-cell electric vehicles as early as 2015.^[16]

In February 2010 Lotus Cars announced that it was developing a fleet of hydrogen taxis in London. London’s deputy mayor, Kit Malthouse, said he hoped six filling stations would be available and that around 20 to 50 taxis would be in operation by the time of the 2012 Olympic Games, as well as 150 hydrogen-powered buses.^[17] In March 2010, General Motors said it had not abandoned fuel-cell technology and is still targeted to introduce hydrogen vehicles to retail customers by 2015. Charles Freese, GM’s executive director of global powertrain engineering, stated that the company believes that both fuel-cell vehicles and battery electric vehicles are needed for reduction of greenhouse gases and reliance on oil, and the U.S. should follow Germany and Japan in adopting a more uniform strategy on advanced technology options. Both countries have announced plans to open 1,000 hydrogen fuel stations.^[18]

Buses

Fuel cell buses (as opposed to hydrogen fueled buses) are being trialed by several manufacturers in different locations. The Fuel Cell Bus Club is a global fuel cell bus testing collaboration.

Hydrogen was first stored in roof mounted tanks, although models are now incorporating onboard tanks. Some double deck models use between floor tanks.

Bicycles

Pearl Hydrogen Power Sources of Shanghai, China, unveiled a hydrogen bicycle at the 9th China International Exhibition on Gas Technology, Equipment and Applications in 2007.

Motorcycles and scooters

ENV develops electric motorcycles powered by a hydrogen fuel cell, including the Crosscage and Biplane. Other manufacturers as Vectrix are working on hydrogen scooters.^[19] Finally, hydrogen fuel cell-electric hybrid scooters are being made such as the Suzuki Burgman Fuel cell scooter^[20] and the FHybrid.^[21]

Quads and tractors

Autostudi S.r.l‘s H-Due^[22] is a hydrogen-powered quad, capable of transporting 1-3 passengers. A concept for a hydrogen powered tractor has been proposed.^[23]

Airplanes

Companies such as Boeing, Lange Aviation, and the German Aerospace Center pursue hydrogen as fuel for manned and unmanned airplanes. In February 2008 Boeing tested a manned flight of a small aircraft powered by a hydrogen fuel cell. Unmanned hydrogen planes have also been tested.^[24] For large passenger airplanes however, The Times reported that “Boeing said that hydrogen fuel cells were unlikely to power the engines of large passenger jet airplanes but could be used as backup or auxiliary power units onboard.”^[25]

In July 2010 Boeing unveiled its hydrogen powered Phantom Eye UAV, powered by two Ford internal combustion engines that have been converted to run on hydrogen.^[26]

In Europe, the Reaction Engines A2 has been proposed to use the thermodynamic properties of liquid hydrogen to achieve very high speed, long distance (antipodal) flight by burning it in a precooled jet engine.

Fork trucks

A HICE forklift or HICE lift truck is a hydrogen fueled, internal combustion engine powered industrial forklift truck used for lifting and transporting materials. The first production HICE forklift truck based on the Linde X39 Diesel was presented at an exposition in Hannover on May 27, 2008. It used a 2.0 litre, 43 kW diesel internal combustion engine converted to use hydrogen as a fuel with the use of a compressor and direct injection.^[27][28] The hydrogen tank is filled with 26 liters of hydrogen at 350 bar pressure.

Rockets

Many large rockets use liquid hydrogen as fuel, with liquid oxygen as an oxidizer. The main advantage of hydrogen rocket fuel is the high effective exhaust velocity compared to kerosene/LOX or UDMH/NTO engines. According to the Tsiolkovsky rocket equation, a rocket with higher exhaust velocity needs less propellant mass to achieve a given change of speed. Before combustion, the hydrogen runs through cooling pipes around the exhaust nozzle to protect the nozzle from damage by the hot exhaust gases.^[29]

The disadvantages of LH2/LOX engines are the low density and low temperature of liquid hydrogen, which means bigger and insulated and thus heavier fuel tanks are needed. This increases the rocket’s structural mass and decreases its efficiency somewhat. Another disadvantage is the poor storability of LH2/LOX-powered rockets: Due to the constant hydrogen boil-off, the rocket can only be fueled shortly before launch, which makes cryogenic engines unsuitable for ICBMs and other rocket applications with the need for short launch preparations.

Liquid hydrogen and oxygen were also used in the Space Shuttle to run the fuel cells that power the electrical systems.^[30] The byproduct of the fuel cell is water, which is used for drinking and other applications that require water in space.

Internal combustion vehicle

Hydrogen internal combustion engine cars are different from hydrogen fuel cell cars. The hydrogen internal combustion car is a slightly modified version of the traditional gasoline internal combustion engine car. These hydrogen engines burn fuel in the same manner that gasoline engines do.

Francois Isaac de Rivaz designed in 1807 the first hydrogen-fueled internal combustion engine.^[31] Paul Dieges patented in 1970 a modification to internal combustion engines which allowed a gasoline-powered engine to run on hydrogen US 3844262 .

Mazda has developed Wankel engines burning hydrogen. The advantage of using ICE (internal combustion engine) like Wankel and piston engines is the cost of retooling for production is much lower. Existing-technology ICE can still be applied for solving those problems where fuel cells are not a viable solution insofar, for example in cold-weather applications.

HICE forklift trucks have been demonstrated^[32] based on converted diesel internal combustion engines with direct injection.^[28]

Fuel cell

While fuel cells themselves are potentially highly energy efficient, and working prototypes were made by Francis Thomas Bacon in 1959^[33] and Roger E. Billings in the 1960s, at least four technical obstacles and other political considerations exist regarding the development and use of a fuel cell-powered hydrogen car: the cost, reliability and durability of the fuel cells; storage of hydrogen for use in fuel cells; production of hydrogen; and delivery of hydrogen to vehicles.^[34]

Fuel cell cost

Currently, hydrogen fuel cells are relatively expensive to produce and some are fragile. As of October 2009, Fortune magazine estimated the cost of producing the Honda Clarity at $300,000 per car.^[35] Also, many designs require rare substances such as platinum as a catalyst in order to work properly. Occasionally, a catalyst can become contaminated by impurities in the hydrogen supply, rendering the fuel cell inoperable. In 2010, research and design advances developed a new nickel-tin nanometal catalyst which lowers the cost of cells.^[36]

Fuel cells are generally priced in USD/kW. The U.S. Department of Energy estimated that the cost of a fuel cell for an automobile in 2002 was approximately $275/kw, which translated into each vehicle costing more than 1 million dollars. However, by 2010, the Department of Energy estimated that the cost had fallen 80% and that such fuel cells could be manufactured for $51/kW, assuming high-volume manufacturing cost savings.^[37] Ballard Power Systems also published similar data. Their 2005 figure was $73 USD/kW (based on high volume manufacturing estimates), which they said was on track to achieve the U.S. Department of Energy’s 2012 goal of $30 USD/kW. This would achieve closer parity with internal combustion engines for automotive applications, allowing a 100 kW fuel cell to be produced for $3000. 100 kW is about 134 hp.^[38]

Freezing conditions

Temperatures below freezing are a concern with fuel cells operations. Operational fuel cells have an internal vaporous water environment that could solidify if the fuel cell and contents are not kept above 0° Celsius (32°F). Most fuel cell designs are not as yet robust enough to survive in below-freezing environments. Frozen solid, especially before start up, they would not be able to begin working. Once running though, heat is a byproduct of the fuel cell process, which would keep the fuel cell at an adequate operational temperature to function correctly. This makes startup of the fuel cell a concern in cold weather operation. Places such as Alaska where temperatures can reach −40 °C (−40 °F) at startup would not be able to use early model fuel cells. Ballard announced in 2006 that it had already hit the U.S. DoE’s 2010 target for cold weather starting which was 50% power achieved in 30 seconds at -20 °C.^[39]

Fuel cells have startup and long term reliability problems. Early gasoline engines had the characteristic of higher heat dissipation once running, whereas fuels cells emit less heat, making the warm up process somewhat slower.^[40]

Service life

Although service life is coupled to cost, fuel cells have to be compared to existing machines with a service life in excess of 5000 hours^[41] for stationary and light-duty. Marine PEM fuel cells reached the target in 2004.^[42] Current service life is 7,300 hours under cycling conditions.^[43] Research is going on especially for heavy duty like in the bus trials which are targeted up to a service life of 30,000 hours.

Hydrogen

Hydrogen does not come as a pre-existing source of energy like fossil fuels, but is first produced and then stored as a carrier, much like a battery. Hydrogen for vehicle uses needs to be produced using either renewable or non-renewable energy sources. A suggested benefit of large-scale deployment of hydrogen vehicles is that it could lead to decreased emissions of greenhouse gases and ozone precursors.^[44]

According to the United States Department of Energy “Producing hydrogen from natural gas does result in some greenhouse gas emissions. When compared to ICE vehicles using gasoline, however, fuel cell vehicles using hydrogen produced from natural gas reduce greenhouse gas emissions by 60%.^[45] While methods of hydrogen production that do not use fossil fuel would be more sustainable,^[46] currently renewable energy represents only a small percentage of energy generated, and power produced from renewable sources can be used in electric vehicles and for non-vehicle applications.^[47]

The challenges facing the use of hydrogen in vehicles include production, storage, transport and distribution. Because of all these challenges, the well-to-wheel efficiency for hydrogen is less than 25%.^[48][49][50]

Production

The molecular hydrogen needed as an on-board fuel for hydrogen vehicles can be obtained through many thermochemical methods utilizing natural gas, coal (by a process known as coal gasification), liquefied petroleum gas, biomass (biomass gasification), by a process called thermolysis, or as a microbial waste product called biohydrogen or Biological hydrogen production. 95% of hydrogen is produced using natural gas,^[51] and 85% of hydrogen produced is used to remove sulfur from gasoline. Hydrogen can also be produced from water by electrolysis or by chemical reduction using chemical hydrides or aluminum.^[52] Current technologies for manufacturing hydrogen use energy in various forms, totaling between 25 and 50 percent of the higher heating value of the hydrogen fuel, used to produce, compress or liquefy, and transmit the hydrogen by pipeline or truck.^[53]

Environmental consequences of the production of hydrogen from fossil energy resources include the emission of greenhouse gases, a consequence that would also result from the on-board reforming of methanol into hydrogen.^[48] Studies comparing the environmental consequences of hydrogen production and use in fuel-cell vehicles to the refining of petroleum and combustion in conventional automobile engines find a net reduction of ozone and greenhouse gases in favor of hydrogen.^[44] Hydrogen production using renewable energy resources would not create such emissions or, in the case of biomass, would create near-zero net emissions assuming new biomass is grown in place of that converted to hydrogen. However the same land could be used to create Biodiesel, usable with (at most) minor alterations to existing well developed and relatively efficient diesel engines. In either case, the scale of renewable energy production today is small and would need to be greatly expanded to be used in producing hydrogen for a significant part of transportation needs.^[54] As of December 2008, less than 3 percent of U.S. electricity was produced from renewable sources, not including dams.^[55] In a few countries, renewable sources are being used more widely to produce energy and hydrogen. For example, Iceland is using geothermal power to produce hydrogen,^[56] and Denmark is using wind.^[57]

Storage

Hydrogen has a very low volumetric energy density at ambient conditions, equal to about one-third that of methane. Even when the fuel is stored as liquid hydrogen in a cryogenic tank or in a compressed hydrogen storage tank, the volumetric energy density (megajoules per liter) is small relative to that of gasoline. Hydrogen has a three times higher energy density by mass compared to gasoline (143 MJ/kg versus 46.9 MJ/kg). Some research has been done into using special crystalline materials to store hydrogen at greater densities and at lower pressures. A recent study by Dutch researcher Robin Gremaud has shown that metal hydride hydrogen tanks are actually 40 to 60-percent lighter than an equivalent energy battery pack on an electric vehicle permitting greater range for H2 cars.^[58] In 2011, scientists at Los Alamos National Laboratory and University of Alabama, working with the U.S. Department of Energy, found a new single-stage method for recharging ammonia borane, a hydrogen storage compound.^[59][60]

Infrastructure

The hydrogen infrastructure consists mainly of industrial hydrogen pipeline transport and hydrogen-equipped filling stations like those found on a hydrogen highway. Hydrogen stations which are not situated near a hydrogen pipeline can obtain supply via hydrogen tanks, compressed hydrogen tube trailers, liquid hydrogen tank trucks or dedicated onsite production.

Hydrogen use would require the alteration of industry and transport on a scale never seen before in history. For example, according to GM, 70% of the U.S. population lives near a hydrogen-generating facility but has little access to hydrogen, despite its wide availability for commercial use.^[61] The distribution of hydrogen fuel for vehicles throughout the U.S. would require new hydrogen stations costing, by some estimates, 20 billion dollars.^[62] and 4.6 billion in the EU.^[63] Other estimates place the cost as high as half trillion dollars in the United States alone.^[64]

The California Hydrogen Highway is an initiative to build a series of hydrogen refueling stations along that state. These stations are used to refuel hydrogen vehicles such as fuel cell vehicles and hydrogen combustion vehicles. As of March 2011, the California Fuel Cell Partnership showed 20 stations in operation, with eight more planned. These are located mostly in and around Los Angeles, with a few in the Bay area^[65][66] South Carolina also has a hydrogen freeway project, and the first two hydrogen fueling stations opened in 2009 in Aiken and Columbia, South Carolina. According to the South Carolina Hydrogen & Fuel Cell Alliance, the Columbia station has a current capacity of 120 kg a day, with future plans to develop on-site hydrogen production from electrolysis and reformation. The Aiken station has a current capacity of 80 kg. There are several funding projects for Hydrogen fuel cell research and infrastructure in South Carolina. The University of South Carolina, a founding member of the South Carolina Hydrogen & Fuel Cell Alliance, received 12.5 million dollars from the Department of Energy for its Future Fuels Program.^[67]

Codes and standards

Hydrogen codes and standards, as well as codes and technical standards for hydrogen safety and the storage of hydrogen, have been identified as an institutional barrier to deploying hydrogen technologies and developing a hydrogen economy. To enable the commercialization of hydrogen in consumer products, new codes and standards must be developed and adopted by federal, state and local governments.^[68]

Criticism

Critics claim the time frame for overcoming the technical and economic challenges to implementing wide-scale use of hydrogen vehicles is likely to last for at least several decades, and hydrogen vehicles may never become broadly available.^[47][69] They claim that the focus on the use of the hydrogen car is a dangerous detour from more readily available solutions to reducing the use of fossil fuels in vehicles.^[70] In May 2008, Wired News reported that “experts say it will be 40 years or more before hydrogen has any meaningful impact on gasoline consumption or global warming, and we can’t afford to wait that long. In the meantime, fuel cells are diverting resources from more immediate solutions.”^[71]

K. G. Duleep speculates that “a strong case exists for continuing fuel-efficiency improvements from conventional technology at relatively low cost.”^[72] Critiques of hydrogen vehicles are presented in the 2006 documentary, Who Killed the Electric Car?. According to former U.S. Department of Energy official Joseph Romm, “A hydrogen car is one of the least efficient, most expensive ways to reduce greenhouse gases.” Asked when hydrogen cars will be broadly available, Romm replied: “Not in our lifetime, and very possibly never.”^[72] The Los Angeles Times wrote, in February 2009, “Hydrogen fuel-cell technology won’t work in cars. … Any way you look at it, hydrogen is a lousy way to move cars.”^[73] A 2007 article in Technology Review stated, “In the context of the overall energy economy, a car like the BMW Hydrogen 7 would probably produce far more carbon dioxide emissions than gasoline-powered cars available today. And changing this calculation would take multiple breakthroughs – which study after study has predicted will take decades, if they arrive at all. In fact, the Hydrogen 7 and its hydrogen-fuel-cell cousins are, in many ways, simply flashy distractions produced by automakers who should be taking stronger immediate action to reduce the greenhouse-gas emissions of their cars.”^[47][74]

The Wall Street Journal reported in 2008 that “Top executives from General Motors Corp. and Toyota Motor Corp. Tuesday expressed doubts about the viability of hydrogen fuel cells for mass-market production in the near term and suggested their companies are now betting that electric cars will prove to be a better way to reduce fuel consumption and cut tailpipe emissions on a large scale.”^[6][75] The Economist magazine, in September 2008, quoted Robert Zubrin, the author of Energy Victory, as saying: “Hydrogen is ‘just about the worst possible vehicle fuel’”.^[76] The magazine noted the withdrawal of California from earlier goals: “In March [2008] the California Air Resources Board, an agency of California’s state government and a bellwether for state governments across America, changed its requirement for the number of zero-emission vehicles (ZEVs) to be built and sold in California between 2012 and 2014. The revised mandate allows manufacturers to comply with the rules by building more battery-electric cars instead of fuel-cell vehicles.”^[76] The magazine also noted that most hydrogen is produced through steam reformation, which creates at least as much emission of carbon per mile as some of today’s gasoline cars. On the other hand, if the hydrogen could be produced using renewable energy, “it would surely be easier simply to use this energy to charge the batteries of all-electric or plug-in hybrid vehicles.”^[76]

The Washington Post asked in November 2009, “But why would you want to store energy in the form of hydrogen and then use that hydrogen to produce electricity for a motor, when electrical energy is already waiting to be sucked out of sockets all over America and stored in auto batteries”? The paper concluded that commercializing hydrogen cars is “stupendously difficult and probably pointless. That’s why, for the foreseeable future, the hydrogen car will remain a tailpipe dream”.^[51] A December 2009 study at UC Davis, published in the Journal of Power Sources, found that, over their lifetimes, hydrogen vehicles will emit more carbon than gasoline vehicles.^[77]

In 2009 the U.S. Secretary of Energy, Stephen Chu, stated that fuel cell hydrogen vehicles “will not be practical over the next 10 to 20 years”. He cited difficulties in the development of the required infrastructure to distribute hydrogen as a justification for cutting research funds.^[78] The National Hydrogen Association and other hydrogen groups criticized the decision.^[79] Secretary Chu told MIT’s Technology Review that he is skeptical about hydrogen’s use in transportation because “the way we get hydrogen primarily is from reforming [natural] gas. … You’re giving away some of the energy content of natural gas. … So that’s one problem. … [For] transportation, we don’t have a good storage mechanism yet. … The fuel cells aren’t there yet, and the distribution infrastructure isn’t there yet. … In order to get significant deployment, you need four significant technological breakthroughs. … If you need four miracles, that’s unlikely: saints only need three miracles”.^[34] Congress reversed the funding cuts in its appropriations bill for 2010,^[7] but the Department of Energy plans to decrease funding for Fuel Cell Vehicle development in its 2012 budget.^[80]

In July 2011, the Chairman and CEO of General Motors, Daniel Akerson, stated that while the cost of hydrogen fuel cell cars is decreasing: “The car is still too expensive and probably won’t be practical until the 2020-plus period, I don’t know.”^[69][81]

Comparison with other types of alternative fuel vehicle

Hydrogen vehicles are one of a number of proposed alternatives to the modern fossil fuel powered vehicle infrastructure.

Plug-in hybrids

Plug-in hybrid electric vehicles, or PHEVs, are hybrid vehicles that can be plugged into the electric grid and contain an electric motor and also an ICE or other engine. The Chevrolet Volt, the first commercially-manufactured PHEV, became commercially available in some U.S. states in 2010 and in more locations in 2011. The PHEV concept augments standard hybrid electric vehicles with the ability to recharge their batteries from an external source while parked, enabling increased use of the vehicle’s electric motors while reducing their reliance on internal combustion engines. The infrastructure required to charge PHEVs is already in place,^[82] and transmission of power from grid to car is about 93% efficient.^[83] This, however, is not the only energy loss in transferring power from grid to wheels. AC/DC conversion must take place from the grids AC supply to the PHEV’s DC. This is roughly 98% efficient.^[84] The battery then must be charged. As of 2007, the Lithium iron phosphate battery was between 80-90% efficient in charging/discharging.^[85] The battery needs to be cooled; the GM Volt’s battery has 4 coolers and two radiators.^[86] As of 2009, “the total well-to-wheels efficiency with which a hydrogen fuel cell vehicle might utilize renewable electricity is roughly 20% (although that number could rise to 25% or a little higher with the kind of multiple technology breakthroughs required to enable a hydrogen economy). The well-to-wheels efficiency of charging an onboard battery and then discharging it to run an electric motor in a PHEV or EV, however, is 80% (and could be higher in the future)—four times more efficient than current hydrogen fuel cell vehicle pathways.”^[50] A 2006 article in Scientific American argued that PHEVs, rather than hydrogen vehicles, would become standard in the automobile industry.^[87][88] A December 2009 study at UC Davis found that, over their lifetimes, PHEVs will emit less carbon than current vehicles, while hydrogen cars will emit more carbon than gasoline vehicles.^[77]

Natural gas

ICE-based CNG or LNG vehicles (Natural gas vehicles or NGVs) use Natural gas or Biogas as a fuel source. Natural gas has a higher energy density than hydrogen gas. Natural gas powered vehicles have a lower carbon dioxide footprint than ICE vehicles. When using Biogas, NGVs become carbon neutral vehicles that run on animal waste.^[89] CNG vehicles have been available for several years, and there is sufficient infrastructure to provide both commercial and home refueling stations. In 2008, the ACEEE rated the Honda Civic GX, which uses compressed natural gas, as the greenest vehicle available.^[90][91][92]

Battery electric vehicles

A 2008 Technology Review article stated, “Electric cars—and plug-in hybrid cars—have an enormous advantage over hydrogen fuel-cell vehicles in utilizing low-carbon electricity. That is because of the inherent inefficiency of the entire hydrogen fueling process, from generating the hydrogen with that electricity to transporting this diffuse gas long distances, getting the hydrogen in the car, and then running it through a fuel cell—all for the purpose of converting the hydrogen back into electricity to drive the same exact electric motor you’ll find in an electric car.”^[93] Thermodynamically, each additional step in the conversion process decreases the overall efficiency of the process.^[94][95] Many BEV designs offer limited driving range. For example, The Nissan Leaf, the first commercially-manufactured BEV, which became available in in some U.S. states beginning in 2010, has a maximum range of 100 miles. Mini E users have reported a range of between 100–120 miles (160–190 km).^[96] However, most commutes are 30–40 miles (48–64 km) miles per day round trip. Ed Begley, Jr., an electric car advocate, noted wryly, “The detractors of electric vehicles are right. Given their limited range, they can only meet the needs of 90 percent of the population.”^[50] In addition, new Nickel-metal hydride and lithium batteries are non-toxic and can be recycled, and “the supposed ‘lithium shortage’ doesn’t exist”.^[50]

See also

Alternative fuel car Bivalent engine Electric vehicle Future of the car

Sustainable development portal Hell and High Water The Hype about Hydrogen Tribrid vehicle World Green Car

References

External links

Wikimedia Commons has media related to: Hydrogen vehicles

• California Fuel Cell Partnership homepage
• Clean Energy Partnership
• C-Net – Hydrogen: More Polluting than Petroleum? Cnet news 2007
• U.S. Dept. of Energy hydrogen pages
• Toronto Star article on hydrogen trains dated October 21, 2007
• NOVA – Video on Fuel Cell Cars (aired on PBS, July 26, 2005)
• Sandia Corporation – Hydrogen internal combustion engine description
• Inside world’s first hydrogen-powered production car BBC News, 14 September 2010

v t e Alternative fuel vehicles Compressed-air engine Compressed air car Compressed-air vehicle Electric motor Battery electric vehicle Electric aircraft Electric bicycle Electric boat Electric car Electric vehicle Electric motorcycles and scooters Hybrid electric vehicle Motorized bicycle Neighborhood Electric Vehicle Plug-in electric vehicle Plug-in hybrid electric vehicle Solar vehicle Wind-powered vehicle Biofuel ICE Alcohol fuel Biodiesel Biogas Butanol fuel Common ethanol fuel mixtures E85 Ethanol fuel Flexible-fuel vehicle Methanol economy Methanol fuel Hydrogen Fuel cell vehicle Hydrogen economy Hydrogen vehicle Hydrogen internal combustion engine vehicle Others Autogas Hybrid electric vehicle Liquid nitrogen vehicle Natural gas vehicle Propane Steam car Wood gas Multiple-fuel Bi-fuel vehicle Flexible-fuel vehicle Hybrid vehicle Multifuel Plug-in hybrid Documentaries Who Killed the Electric Car? What Is the Electric Car? Revenge of the Electric Car See also Zero-emissions vehicle

v t e Emerging technologies Technology Fields Agriculture Agricultural robot In vitro meat Genetically modified food Precision agriculture Vertical farming Biomedical Ampakine Cryonics Full genome sequencing Genetic engineering Gene therapy Personalized medicine Regenerative medicine Stem cell treatments Tissue engineering Robotic surgery Strategies for Engineered Negligible Senescence Suspended animation Synthetic biology Synthetic genomics Whole-body transplant Head transplant Isolated brain Displays Autostereoscopy Holographic display Next generation of display technology Screenless display Bionic contact lens Head-mounted display Head-up display Virtual retinal display Ultra High Definition Television Electronics Electronic nose Electronic textile Flexible electronics Memristor Spintronics Thermal copper pillar bump Energy Energy storage Beltway battery Compressed air energy storage Flywheel energy storage Grid energy storage Lithium air battery Molten salt battery Nanowire battery Silicon air battery Thermal energy storage Ultracapacitor Fusion power Molten salt reactor Renewable energy Airborne wind turbine Artificial photosynthesis Biofuels Concentrated solar power Home fuel cell Hydrogen economy Nantenna Solar roadway Space-based solar power Smart grid Wireless energy transfer IT and communications Artificial intelligence Applications of artificial intelligence Progress in artificial intelligence Machine translation Machine vision Semantic Web Speech recognition Atomtronics Cybermethodology Fourth-generation optical discs 3D optical data storage Holographic data storage GPGPU Memory CBRAM FRAM Millipede MRAM NRAM PRAM Racetrack memory RRAM SONOS Optical computing Quantum computing Quantum cryptography RFID Three-dimensional integrated circuit Manufacturing 3D printing Contour Crafting Claytronics Molecular assembler Utility fog Materials science Graphene High-temperature superconductivity High-temperature superfluidity Metamaterials Metamaterial cloaking Multi-function structures Nanotechnology Carbon nanotubes Molecular nanotechnology Nanomaterials Programmable matter Quantum dots Military Antimatter weapon Directed-energy weapon Laser Maser Particle beam weapon Sonic weapon Electromagnetic weapon Coilgun Railgun Plasma weapon Pure fusion weapon Neuroscience Artificial brain Blue Brain Project Electroencephalography Mind uploading Brain-reading Neuroinformatics Neuroprosthetics Bionic eye Brain implant Exocortex Retinal implant Robotics Nanorobotics Powered exoskeleton Self-reconfiguring modular robot Swarm robotics Transport Adaptive Compliant Wing Alternative fuel vehicle Hydrogen vehicle Backpack helicopter Driverless car Flying car Ground effect train Jet pack Interstellar travel Laser propulsion Maglev train Non-rocket spacelaunch Mass driver Orbital ring Skyhook Space elevator Space fountain Space tether Personal rapid transit ETT Pulse detonation engine Nuclear pulse propulsion Scramjet Solar sail Spaceplane Supersonic transport Tweel Vactrain Other Anti-gravity Arcology Cloak of invisibility Digital scent technology Domed city Force field Plasma window Immersive virtual reality Magnetic refrigeration Phased-array optics Quantum technology Quantum teleportation Other Differential technological development Ephemeralization Exploratory engineering Fictional technology Technological convergence Technological evolution Technology forecasting Accelerating change Moore’s law Timeline of the future in forecasts Technological singularity Technology scouting Technology readiness level Technology roadmap Transhumanism Virtusphere Category List

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

v t e Alternative fuel vehicles Compressed-air engine Compressed air car Compressed-air vehicle Electric motor Battery electric vehicle Electric aircraft Electric bicycle Electric boat Electric car Electric vehicle Electric motorcycles and scooters Hybrid electric vehicle Motorized bicycle Neighborhood Electric Vehicle Plug-in electric vehicle Plug-in hybrid electric vehicle Solar vehicle Wind-powered vehicle Biofuel ICE Alcohol fuel Biodiesel Biogas Butanol fuel Common ethanol fuel mixtures E85 Ethanol fuel Flexible-fuel vehicle Methanol economy Methanol fuel Hydrogen Fuel cell vehicle Hydrogen economy Hydrogen vehicle Hydrogen internal combustion engine vehicle Others Autogas Hybrid electric vehicle Liquid nitrogen vehicle Natural gas vehicle Propane Steam car Wood gas Multiple-fuel Bi-fuel vehicle Flexible-fuel vehicle Hybrid vehicle Multifuel Plug-in hybrid Documentaries Who Killed the Electric Car? What Is the Electric Car? Revenge of the Electric Car See also Zero-emissions vehicle