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Fuel efficiency, in its basic sense, is the same as thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. In Thermodynamics, the thermal efficiency (\eta_{th} \ is a dimensionless performance measure of a thermal device such as an Internal combustion Fuel is any material that is burned or altered in order to obtain energy The kinetic energy of an object is the extra Energy which it possesses due to its motion In Physics, mechanical work is the amount of Energy transferred by a Force. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. In Standardization, a profile consists of an agreed-upon subset and interpretation of a Specification. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process. For other uses of this term see Industry (disambiguation An industry (from Latin industrius, "diligent industrious" A fossil fuel power plant burns Fossil fuels such as Coal, Natural gas or Petroleum (oil to produce Electricity. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor The Haber process, also called the Haber–Bosch process, is the Nitrogen fixation reaction of Nitrogen and Hydrogen, over an iron substrate

In the context of transportation, "fuel efficiency" more commonly refers to the energy efficiency of a particular vehicle model, where its total output (range, or "mileage" [U. Transport or transportation is the movement of people and goods from one place to another Fuel economy in automobiles is the amount of Fuel required to move the Automobile over a given Distance. S. ]) is given as a ratio of range units per a unit amount of input fuel (gasoline, diesel, etc. A ratio is an expression which compares quantities relative to each other ). This ratio is given in common measures such as "liters per 100 kilometers" (L/100 km) (common in Europe and Canada) or "miles per gallon" (mpg) (prevalent in USA and UK, using their respective gallon measurements) or "kilometers per liter"(kmpl) (prevalent in India). The litre or liter (see spelling differences) is a unit of Volume. The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand A mile is a unit of Length, usually used to measure Distance, in a number of different systems including Imperial units United States A gallon is a measure of Volume. It is in current use in the United States and still has limited use in many other English-speaking countries Fuel economy in automobiles is the amount of Fuel required to move the Automobile over a given Distance. Though the typical output measure is vehicle range, for certain applications output can also be measured in terms of weight per range units (freight) or individual passenger-range (vehicle range / passenger capacity). Cargo (or freight) refers to goods or produce transported generally for Commercial gain by ship, aircraft, train,

This ratio is based on a car's total properties, including its engine properties, its body drag, weight, and rolling resistance (friction), and as such may vary substantially from the profile of the engine alone. An engine is a mechanical device that produces some form of output from a given input Body drag is the name given to a freestyle trick performed by a Windsurfer. While the thermal efficiency of petroleum engines has improved in recent decades, this does not necessarily translate into fuel economy of cars, as people in developed countries tend to buy bigger and heavier cars (i. Petroleum ( L petroleum, from Greek πετρέλαιον, lit The internal combustion engine is an engine in which the Combustion of Fuel and an Oxidizer (typically air occurs in a confined space called a The term developed country, or advanced country, is used to categorize countries with developed Economies in which the tertiary and quaternary sectors e. SUVs will get less range per unit fuel than an economy car). A sport utility vehicle ( SUV) is a generic marketing description for a rugged automotive vehicle similar to a Station wagon but built on a light-truck chassis An economy car is an Automobile that is designed for Low cost operation

Hybrid vehicle designs use smaller combustion engines as electric generators to produce greater range per unit fuel than directly powering the wheels with an engine would, and (proportionally) less fuel emissions (CO2 grams) than a conventional (combustion engine) vehicle of similar size and capacity. A hybrid vehicle is a vehicle that uses two or more distinct power sources to propel the vehicle Air pollution is the human introduction into the atmosphere of Chemicals Particulate matter, or Biological materials that cause harm or discomfort Carbon dioxide equivalent ( CDE) and Equivalent carbon dioxide (or CO2e) are two related but distinct measures for describing how much Global

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Energy-efficiency terminology

"Energy efficiency" is similar to fuel efficiency but the input is usually in units of energy such as British thermal units (BTU), megajoules (MJ), gigajoules (GJ), kilocalories (kcal), or kilowatt-hours (kW·h). The inverse of "energy efficiency" is "energy intensity", or the amount of input energy required for a unit of output such as MJ/passenger-km (of passenger transport), BTU/ton-mile (of freight transport, for long/short/metric tons), GJ/t (for steel production), BTU/(kW·h) (for electricity generation), or litres/100 km (of vehicle travel). This last term "litres per 100 km" is also a measure of "fuel economy" where the input is measured by the amount of fuel and the output is measured by the distance travelled. Distance is a numerical description of how far apart objects are For example: Fuel economy in automobiles. Fuel economy in automobiles is the amount of Fuel required to move the Automobile over a given Distance.

Given a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units:

Energy content of fuel

The specific energy content of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram, etc. ). It is sometimes called the "heat of combustion". There exists two different values of specific heat energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the "exhaust" is in liquid form. For the low value, the "exhaust" has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the high value is larger since it includes the latent heat of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U. S. (and the table below) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used.

Fuel type     MJ/L     MJ/kg    BTU/Imp gal    BTU/US gal    Research octane
number (RON)
Regular Gasoline / Petrol34. A gallon is a measure of Volume. It is in current use in the United States and still has limited use in many other English-speaking countries A gallon is a measure of Volume. It is in current use in the United States and still has limited use in many other English-speaking countries The octane rating is a measure of the resistance of Gasoline and other Fuels to Detonation ( Engine knocking) in spark-ignition 83~47150,100125,000Min 91
Premium Gasoline / Petrol~46Min 95
Autogas (LPG) (60% Propane + 40% Butane)~51
Ethanol23. Autogas is the common name for Liquified petroleum gas (LPG when it is used as a Fuel in Internal combustion engines in Vehicles. Liquefied petroleum gas (also called LPG, GPL, LP Gas, or Autogas) is a mixture of Hydrocarbon Gases used as a Fuel Propane is a three- Carbon Alkane, normally a gas but compressible to a liquid that is transportable Butane, also called n -butane, is the unbranched Alkane with four Carbon Atoms CH3CH2CH2CH3 Ethanol fuel is Ethanol (ethyl alcohol the same type of Alcohol found in Alcoholic beverages. 531. 1[1]101,60084,600129
Methanol17. Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a Chemical compound 919. 977,60064,600123
Gasohol (10% ethanol + 90% gasoline)33. Although Fossil fuels have become the dominant Energy resource for the modern world Alcohol has been used as a fuel throughout history 7~45145,200120,90093/94
Diesel38. Diesel or Diesel fuel (ˈdiːzəl in general is any Fuel used in Diesel engines The most common is a specific fractional distillate of petroleum 60~48166,600138,700N/A (see cetane)
Biodiesel35. Cetane number or CN is a measurement of the Combustion quality of Diesel fuel during compression ignition Biodiesel refers to a non-petroleum-based Diesel fuel consisting of short chain Alkyl ( Methyl or ethyl) Esters made by 1039. 89151,600126,200
Vegetable oil (using 9. For engines designed to burn #2 diesel fuel the Viscosity of vegetable oil must be lowered to allow for proper Atomization of fuel otherwise incomplete combustion 00 kcal/g)34. 3237. 66147,894123,143
Aviation gasoline33. Avgas is a high-octane Aviation fuel used for Aircraft and Racing cars Avgas is a Portmanteau for aviation gasoline 546. 8144,400120,200
Jet fuel, naphtha35. Jet fuel is a type of Aviation fuel designed for use in Aircraft powered by gas-turbine engines. 546. 6153,100127,500
Jet fuel, kerosene37. Jet fuel is a type of Aviation fuel designed for use in Aircraft powered by gas-turbine engines. 60162,100135,000
Liquefied natural gas25. Not to be confused with Natural Gas Liquids (NGL Liquefied natural gas or LNG is Natural gas (primarily Methane, CH4 3~55109,00090,800
Liquid hydrogen9. Liquid hydrogen (LH2 or LH2 is the Liquid state of the element Hydrogen. 36140. 440,46733,696

Neither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in Gibbs free energy, and is around 45. In Thermodynamics, the Gibbs free energy ( IUPAC recommended name Gibbs energy or Gibbs function) is a Thermodynamic potential which 7 MJ/kg for gasoline. ) The actual amount of mechanical work obtained from fuel (the inverse of the specific fuel consumption) depends on the engine. Specific fuel consumption, often shortened to SFC, or TSFC is an Engineering term that is used to describe the Fuel efficiency of an Engine A figure of 17. 6 MJ/kg is possible with a gasoline engine, and 19. 1 MJ/kg for a diesel engine. See specific fuel consumption for more information. Specific fuel consumption, often shortened to SFC, or TSFC is an Engineering term that is used to describe the Fuel efficiency of an Engine

Fuel economy

Main article: Fuel economy in automobiles

Fuel economy is usually expressed in one of two ways:

Converting from mpg or to L/100 km (or vice versa) involves the use of the reciprocal function, which is not distributive. In Mathematics, a multiplicative inverse for a number x, denoted by 1&frasl x or x &minus1 is a number which In Mathematics, and in particular in Abstract algebra, distributivity is a property of Binary operations that generalises the distributive law Therefore, the average of two fuel economy numbers gives different values if those units are used. If two people calculate the fuel economy average of two groups of cars with different units, the group with better fuel economy may be one or the other.

The formula for converting to miles per US gallon (3. 785 L) from L/100 km is \frac{235.2}{x}, where x is value of L/100km. For miles per Imperial gallon (4. 546 L) the formula is \frac{282.5}{x}.

In Europe, the two standard measuring cycles for "L/100 km" value are motorway travel at 90 km/h and rush hour city traffic. Motorway is a term for both a type of Road and a classification or designation A reasonably modern European supermini may manage motorway travel at 5 L/100 km (47 mpg US) or 6. A supermini is a British Car classification term that describes Automobiles larger than a City car but smaller than a Small family car. Motorway is a term for both a type of Road and a classification or designation 5 L/100 km in city traffic (36 mpg US), with carbon dioxide emissions of around 140 g/km. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single

An average North American mid-size car travels 27 mpg (US) (9 L/100 km) highway, 21 mpg (US) (11 L/100 km) city; a full-size SUV usually travels 13 mpg (US) (18 L/100 km) city and 16 mpg (US) (15 L/100 km) highway. A mid-size car (occasionally referred to as an intermediate) is the North American and Australian term for an Automobile with a size between A full-size car is a Marketing term used in North America for an Automobile larger than a Mid-size car. A sport utility vehicle ( SUV) is a generic marketing description for a rugged automotive vehicle similar to a Station wagon but built on a light-truck chassis Pickup trucks vary considerably; whereas a 4 cylinder-engined light pickup can achieve 28 mpg (8 L/100 km), a V8 full-size pickup with extended cabin only travels 13 mpg (US) (18 L/100 km) city and 15 mpg (US) (15 L/100 km) highway. A pickup truck is a light Motor vehicle with an open-top rear cargo area which is almost always separated from the cab to allow for chassis flex when carrying or pulling A V8 engine is a V engine with eight cylinders mounted on the Crankcase in two banks of four cylinders in most cases set at a right angle to each other

So, in general, cars are far more fuel-efficient in Europe. Part is because there are lots of diesel vehicles (more efficient) nevertheless, gasoline vehicles are also more efficient. The problem in the US is that American car buyers have downplayed the importancy of energy usage and polution, relative to flexibility and cost of ownership. [2]

An interesting example of fuel economy is the microcar Smart Fortwo cdi, which can achieve up to 3. A microcar is an extremely small Automobile, popularly referred to as Cyclecars in the 1910s and 1920s and Bubblecars in the 1950s and 1960s many of which The smart fortwo is a rear-engined two-seater It was first shown at the 1998 Paris Motor Show. 4 L/100 km (69. 2 mpg US) using a turbocharged three-cylinder 41 hp (30 kW) Diesel engine. A turbocharger, or turbo, is an air Compressor used for forced-induction of an Internal combustion engine. The Fortwo is produced by DaimlerChrysler and is currently only sold by one company in the United States (see external link ZAP). Daimler AG ( (formerly DaimlerChrysler AG) is a German car corporation (not to be confused with the British car-maker Daimler Motor Company) and The current record in fuel economy of production cars is held by Volkswagen, with a special production model of the Volkswagen Lupo (the Lupo 3L) that can consume as little as 3 litres per 100 kilometres (78 miles per US gallon or 94 miles per Imperial gallon). The Volkswagen Lupo is a City car manufactured by German automaker Volkswagen from 1998 to 2005 The litre or liter (see spelling differences) is a unit of Volume. The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand US customary units, also known in the United States as English units or Imperial units (in reference to the British Empire) (but see English A gallon is a measure of Volume. It is in current use in the United States and still has limited use in many other English-speaking countries Imperial units or the Imperial system is a collection of units first defined in the British Weights and Measures Act of 1824 The last Lupo was built in July 2005.

Diesel engines often achieve greater fuel efficiency than petrol (gasoline) engines. A diesel engine is an Internal combustion engine which operates using the Diesel cycle (named after Dr Diesel engines have energy efficiency of 45% and petrol engines of 30%. [3] That is one of the reasons why diesels have better fuel efficiency that equivalent petrol cars. A common margin is 40% more miles per gallon for an efficient turbodiesel. For example, the current model Skoda Octavia, using Volkswagen engines, has a combined European fuel efficiency of 38. 2 mpg for the 102 bhp petrol engine and 53. 3 mpg for the 105 bhp — and heavier — diesel engine. The higher compression ratio is helpful in raising efficiency, but diesel fuel also contains approximately 10-20% more energy per unit volume than gasoline. [4]

Fuel efficiency in microgravity

How fuel combusts affects how much energy is produced. The National Aeronautics and Space Administration (NASA) has investigated fuel consumption in microgravity. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program

The common distribution of a flame under normal gravity conditions depends on convection, because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. Convection in the most general terms refers to the movement of molecules within Fluids (i In microgravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient. Weightlessness is a phenomenon experienced by people during Free-fall. Outer space, often simply called space, comprises the relatively empty regions of the Universe outside the escape velocities of Celestial bodies. "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe There are several possible explanations for this difference, of which the most likely one given is that the cause is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs. [5] Experiments by NASA in microgravity reveal that diffusion flames in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions. In Combustion, a diffusion flame is a Flame in which the Oxidizer combines with the Fuel by Diffusion. [6] Premixed flames in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer. A premixed flame is a Flame in which the Oxidizer has been mixed with the Fuel before it reaches the flame front [7]

Transportation

Fuel efficiency in transportation

Main article: Fuel efficiency in transportation

Vehicle efficiency and transportation pollution

Main articles: Gas-guzzler and Vehicle Efficiency Initiative

Fuel efficiency directly affects emissions causing pollution and potentially leading to climate change by affecting the amount of fuel used. This page describes Fuel efficiency in means of Transportation. Gas-guzzler commonly refers to a vehicle that makes inefficient use of Fuel. The Vehicle Efficiency Incentive (VEI was introduced in the 2007 Canadian federal government budget aimed at promoting fuel efficient vehicles Climate change is any long-term significant change in the “average weather” that a given region experiences However, it also depends on the fuel source used to drive the vehicle concerned. Cars can, for example, run on a number of fuel types other than gasoline, such as natural gas, LPG or biofuel or electricity which creates various quantities of atmospheric pollution. "NGV" redirects here For the art gallery in Melbourne Australia see National Gallery of Victoria.

A kilogram of petrol, diesel, kerosene and the like in a vehicle leads to approximately 3. 15 kg of CO2 emissions, or 2. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single 3 kg/L (19 lb/gal). This figure is only the CO2 emissions of the final fuel product and does not include additional CO2 emissions created during the drilling, pumping, transportation and refining steps required to produce the fuel. Additional measures to reduce overall emission includes improvements to the efficiency of air conditioners, lights and tires. An air conditioner is an Appliance, System, or mechanism designed to extract Heat from an area via a Refrigeration cycle

There is also a growing movement of drivers who practice ways to increase their MPG and save fuel through driving techniques. They are often referred to as hypermilers. Fuel economy-maximizing behaviors describe techniques that drivers can use to optimize their automobile fuel economy. Hypermilers have broken records of fuel efficiency, averaging 109 miles per gallon driving a Prius. The Toyota Prius is a hybrid electric Mid-size car developed and manufactured by the Toyota Motor Corporation In non-hybrid vehicles these techniques are also beneficial. Hypermiler Wayne Gerdes can get 59 MPG in a Honda Accord and 30 MPG in an Acura MDX. The Honda Accord is series of midrange Automobile manufactured by Honda since 1976 and sold in most automotive markets throughout the world The Acura MDX ( Honda MDX in Japan and Australia) is a Mid-size Crossover SUV produced by the Japanese automaker [8]

Hybrid vehicles can conserve petroleum fuel and therefore be more efficient than conventional vehicles. A hybrid vehicle is a vehicle that uses two or more distinct power sources to propel the vehicle

The most efficient machines for converting energy to rotary motion are electric motors, as used in electric vehicles. The Electric Vehicle was an American Automobile manufactured only in 1899 However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. Currently railway trains can be powered using electricity, delivered through an additional running rail, overhead catenary system or by onboard generators used in diesel-electric locomotives as common on the UK rail network. "Railroad" and "Railway" both redirect here For other uses see Railroad (disambiguation. In Physics and Geometry, the catenary is the theoretical Shape of a hanging flexible Chain or Cable when supported at its ends and A number of vehicles use a diesel-electric Powertrain for providing locomotion. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than "on site". Some railways, such as the french SNCF and Swiss federal railways derive most, if not 100% of their current, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a Eurostar train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO2, per passenger, than planes, helped in part by french nuclear generation which, however, creates its own radioactive waste which air flight does not. Radioactive wastes are Waste types containing radioactive Chemical elements that do not have a practical purpose So only comparing CO2 is misleading. [9]. This can be changed using more renewable sources for electric generation. Renewable energy is Energy generated from Natural resources mdashsuch as Sunlight, Wind, Rain, tides and geothermal Electricity generation is the process of converting non-electrical Energy to Electricity.

In the future hydrogen cars may be commercially available. A hydrogen vehicle is a Vehicle that uses Hydrogen as its on-board fuel for motive power Powered either through chemical reactions in a fuel cell that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a natural gas vehicle, and similarly compatible with both natural gas and gasoline); these vehicles promise to have near zero pollution from the tailpipe (exhaust pipe). A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the "NGV" redirects here For the art gallery in Melbourne Australia see National Gallery of Victoria. Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by electrolysis using electricity from nonpolluting sources such as solar, wind, or hydroelectricity. In chemistry and manufacturing electrolysis is a method of separating chemically bonded elements and compounds by passing an Electric current Hydroelectricity is electricity generated by Hydropower, ie the production of power through use of the gravitational force of falling water One advantage of fuel cell vehicles is that they can electrolyze water using their own fuel cells, operating in exactly the same closed-loop fashion as any other rechargeable electric battery.

In any process, it is vitally important to account for all of the energy used throughout, i. e. , cradle-to-grave. Thus, in addition to the energy cost of the electricity or hydrogen production, we must also account for transmission and/or storage losses to support large-scale use of such vehicles. For this reason the use of the idea "zero pollution" should be avoided.

See also

References

  1. ^ Calculated from heats of formation. The annual fuel utilization efficiency ( AFUE; pronounced 'A'-'Few' is a Thermal efficiency measure of combustion equipment like Furnaces Boilers The ACEA agreement refers to a voluntary agreement between the European Automobile Manufacturers Association (ACEA and the European Commission to limit the amount Alternative propulsion is a term used frequently for Powertrain concepts differing from the Internal combustion engine concept used in only Petroleum fueled The Association for the Study of Peak Oil and Gas, or ASPO, is a network of scientists affiliated with a wide array of global institutions and universities Carbon dioxide equivalent ( CDE) and Equivalent carbon dioxide (or CO2e) are two related but distinct measures for describing how much Global Emission standards are requirements that set specific limits to the amount of Pollutants that can be released into the environment Energy conservation is the practice of decreasing the quantity of energy used A Table of Energy Content and CO2 Output of Common Fuels Energy is the ability to do work Energy density is the amount of Energy stored in a given system or region of space per unit Volume, or per unit Mass, depending on the context although Fuel economy in automobiles is the amount of Fuel required to move the Automobile over a given Distance. This page describes Fuel efficiency in means of Transportation. Gas-guzzler commonly refers to a vehicle that makes inefficient use of Fuel. The heat of combustion (ΔHc0 is the Energy released as Heat when a compound undergoes complete Combustion with Oxygen A Low-energy vehicle is any type of vehicle that uses less energy than a regular Petroleum fuel vehicle Road transport ( British English) or road transportation ( American English) is Transport on Roads of passengers or goods Does not correspond exactly to the figure for MJ/L divided by density.
  2. ^ EuropeVsUS Efficiency
  3. ^ Diesel engines - Products : Volvo Group - Global
  4. ^ Diesel Engines
  5. ^ CFM-1 experiment results, National Aeronautics and Space Administration, April 2005.
  6. ^ LSP-1 experiment results, National Aeronautics and Space Administration, April 2005.
  7. ^ SOFBAL-2 experiment results, National Aeronautics and Space Administration, April 2005.
  8. ^ Gaffney, Dennis. "This Guy Can Get 59 MPG in a Plain Old Accord. Beat That, Punk.", Mother Jones, 2007-01-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Retrieved on 2007-04-20. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1303 - The University of Rome La Sapienza is instituted by Pope Boniface VIII.  
  9. ^ European Federation for Transport and Environment

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