Fuel efficiency
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Fuel efficiency (or fuel economy) is a form of
In the context of
Fuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.
Vehicle design
Fuel efficiency is dependent on many parameters of a vehicle, including its engine parameters, aerodynamic drag, weight, AC usage, fuel and rolling resistance. There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.[3]
Fleet efficiency
Fleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient.[5]
Energy efficiency terminology
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:
- There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below).
- When comparing transportation energy costs, it must be remembered that a kilowatt hourof electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it.
Energy content of fuel
The specific
Fuel type | MJ/L | MJ/kg | BTU/imp gal | BTU/ US gal
|
Research octane number (RON) |
---|---|---|---|---|---|
Regular gasoline/petrol | 34.8 | ~47 | 150,100 | 125,000 | Min. 91 |
Premium gasoline/petrol | ~46 | Min. 95 | |||
Autogas (LPG) (60% propane and 40% butane) | 25.5–28.7 | ~51 | 108–110 | ||
Ethanol | 23.5 | 31.1[7] | 101,600 | 84,600 | 129 |
Methanol | 17.9 | 19.9 | 77,600 | 64,600 | 123 |
Gasohol (10% ethanol and 90% gasoline) | 33.7 | ~45 | 145,200 | 121,000 | 93/94 |
E85 (85% ethanol and 15% gasoline) | 25.2 | ~33 | 108,878 | 90,660 | 100–105 |
Diesel | 38.6 | ~48 | 166,600 | 138,700 | N/A (see cetane) |
Biodiesel | 35.1 | 39.9 | 151,600 | 126,200 | N/A (see cetane) |
Vegetable oil (using 9.00 kcal/g)
|
34.3 | 37.7 | 147,894 | 123,143 | |
Aviation gasoline
|
33.5 | 46.8 | 144,400 | 120,200 | 80-145 |
Jet fuel, naphtha | 35.5 | 46.6 | 153,100 | 127,500 | N/A to turbine engines |
Jet fuel, kerosene | 37.6 | ~47 | 162,100 | 135,000 | N/A to turbine engines |
Liquefied natural gas | 25.3 | ~55 | 109,000 | 90,800 | |
Liquid hydrogen | 9.3 | ~130 | 40,467 | 33,696 |
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
Transportation
The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy.[9][10] The energy efficiency is also occasionally known as energy intensity.[11] The inverse of the energy efficiency in transport is the energy consumption in transport.
Energy efficiency in transport is often described in terms of
Therefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m/J, while the energy consumption in transport is measured in terms of joules per metre, or J/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The
Fuel efficiency of motor vehicles
The
Different methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses (
Driving technique
Energy-efficient driving techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly.[13] Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency.[14] Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called "hypermiling".[15]
Simple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles.Advanced technology
The most efficient machines for converting energy to rotary motion are electric motors, as used in
Hydrogen fuel cells
In the future, hydrogen cars may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. 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). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by electrolysis using electricity from non-polluting sources such as solar, wind or hydroelectricity or nuclear. Commercial hydrogen production uses fossil fuels and produces more carbon dioxide than hydrogen.
Because there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label "zero pollution" applies only to the car's conversion of stored energy into movement.
In 2004, a consortium of major auto-makers —
In microgravity
How fuel combusts affects how much energy is produced. The
The common distribution of a flame under normal gravity conditions depends on
See also
- Annual fuel utilization efficiency (AFUE)
- ACEA agreement
- Alternative propulsion
- Camless piston engine
- Carbon dioxide equivalent
- Corporate Average Fuel Economy(CAFE)
- EcoAuto (in Canada)
- Efficient energy use
- Emission standard
- Energy content of Biofuel
- Energy conservation
- Energy conversion efficiency
- Energy density
- FF layout
- Front-wheel drive
- Fuel economy in aircraft
- Fuel economy in automobiles
- Fuel economy maximising behaviors
- Fuel efficiency in transportation
- Gas-guzzler
- Heating value
- Jevons paradox
- Life cycle assessment
- Low-rolling resistance tires
- Miles per gallon gasoline equivalent
- Marine fuel management
- Twinjet
- Variable valve timing
- Unibody
- Automobile costs
- Vehicle metrics
References
- ^ "Information on the fuel consumption of new cars". Archived from the original on 8 September 2019. Retrieved 7 November 2019.
- ^ "Learn More About the Fuel Economy Label for Gasoline Vehicles". Archived from the original on 2013-07-05.
- ^ "Simple tips and tricks to increase fuel efficiency of your car | CarSangrah". CarSangrah. 2018-06-07. Retrieved 2018-07-24.
- U.S. Department of Energy. Archivedfrom the original on 2015-07-08. Retrieved 2014-01-16.
- ^ a b "Highlights of the Automotive Trends Report". EPA.gov. U.S. Environmental Protection Agency (EPA). 12 December 2022. Archived from the original on 2 September 2023.
- doi:10.7922/G2HM56SV. Archived(PDF) from the original on 26 November 2023.
- ^ Calculated from heats of formation. Does not correspond exactly to the figure for MJ/L divided by density.
- Center for Transportation Analysis of the Oak Ridge National Laboratory
- ^ "Efficiency". Retrieved 18 September 2016.
- ^ ISBN 978-0-309-15607-3. Retrieved 18 September 2016.
- U.S. Department of Energy. Retrieved 20 September 2016.
- ^ Page, Walter Hines; Page, Arthur Wilson (1916). "Man and His Machines". The World's Work. Vol. XXXIII. Garden City, New York: Doubleday, Page & Co.
- from the original on 2013-10-19.
- ^ "20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump". Archived from the original on 2016-08-16.
- ^ http://www.merriam-webster.com/dictionary/hypermiling Merriam Webster dictionary
- ^ "Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment". Archived from the original on 2007-09-28.
- ^ Top Tier Gasoline Archived 2013-08-15 at the Wayback Machine
- ^ "Deposit Control Standards". Archived from the original on 2004-08-06. Retrieved 2012-10-19.
- ^ SOFBAL-2 experiment results Archived 2007-03-12 at the Wayback Machine, National Aeronautics and Space Administration, April 2005.
External links
This article's use of external links may not follow Wikipedia's policies or guidelines. (November 2023) |
- US Government website on fuel economy
- UK DfT comparisons on road and rail
- NASA Offers a $1.5 Million Prize for a Fast and Fuel-Efficient Aircraft Archived 2016-03-03 at the Wayback Machine
- Car Fuel Consumption Official Figures
- Spritmonitor.de "the most fuel efficient cars" - Database of thousands of (mostly German) car owners' actual fuel consumption figures (cf. Spritmonitor)
- Searchable fuel economy data from the EPA - United States Environmental Protection Agency
- penghemat bbm - Alat penghemat bbm
- Ny Times: A Road Test of Alternative Fuel Visions