Alternative Fuel Vehicle refers to a vehicle that runs on a fuel other than traditional gasoline or diesel - any method of powering an engine that does not involve solely petroleum like electric car, gasoline-electric hybrid, solar powered.
Alternative Fuel Vehicles
Due to a combination of heavy taxes on fuel, particularly in Europe, tightening environmental laws, particularly in California, and the possibility of further restrictions on greenhouse gas
emissions, work on alternative power systems for vehicles has become a
high priority for governments and vehicle manufacturers around the
Current research and development is largely centered on "hybrid"
vehicles that use both electric power and internal combustion. The
first hybrid vehicle available for sale in the United States was the Honda Insight, achieving around 70 miles per gallon (25.5km per liter).
Other R & D efforts in alternative forms of power focus on developing fuel cells, alternative forms of combustion such as GDI and HCCI, and even the stored energy of compressed air (see Air Engine).
The air engine is an emission-free piston engine that uses
compressed air as a source of energy. The first compressed air car was
invented by a French engineer named Guy Nègre, 58.
The expansion of compressed air may be used to drive the pistons in
a modified piston engine. Efficiency of operation is gained through the
use of environmental heat at normal temperature to warm the otherwise
cold expanded air from the storage tank. This non-adiabatic expansion
has the potential to greatly increase the efficiency of the machine.
The only exhaust is cold air (−15 °C), which could also be used to air
condition the car. The source for air is a pressurized carbon-fiber
tank holding air at 3,000 lbf/in² (20 MPa). Air is delivered to the
engine via a rather conventional injection system. Unique crank design
within the engine increases the time during which the air charge is
warmed from ambient sources and a two stage process allows improved
heat transfer rates.
This engine was used to power an urban car with room for five
passengers and a projected range of about 100 to 200 miles (160 to 320
km), depending on traffic conditions. The main advantages are: no
roadside emissions, low cost technology, engine uses food oil for
lubrication (just about 1 liter, changes only every 30,000 miles
(50,000 km)) and integrated air conditioning. Range could be quickly
tripled, since there are already carbon fiber tanks which have passed
safety standards holding gas at 10,000 lbf/in² (70 MPa).
The tanks may be refilled in about three minutes at a service
station, or in a few hours at home plugging the car into the electric
grid via an on-board compressor. The cost of refilling is projected to
be about US$3.
Battery Electric Vehicles (BEVs) are electric vehicles whose main
energy storage is in the chemical energy of batteries. BEVs are the
most common form of what is defined by the California Air Resources
Board (CARB) as zero emission (ZEV) passenger automobiles, because they
produce no emissions while being driven. The electrical energy carried
onboard a BEV to power the motors is obtained from a variety of battery
chemistries arranged into battery packs. For additional range genset
trailers or pusher trailers are sometimes used, forming a type of
hybrid vehicle. Batteries used in electric vehicles include "flooded"
lead-acid, absorbed glass mat, NiCd, nickel metal hydride, Li-ion,
Li-poly and zinc-air batteries.
Attempts at building viable, modern battery-powered electric vehicle began in the 1950s with the introduction of the first modern (transistor controlled) electric car - the Henney Kilowatt.
Despite the poor sales of the early battery-powered vehicles,
development of various battery-powered vehicles continued through the
1990s (notably General Motors with the EV1), but cost, speed and inadequate driving range continued to make them impractical. Battery powered cars have primarily used lead-acid batteries and NiMH batteries.
Lead-acid batteries' recharge capacity is considerably reduced if
they're discharged beyond 75% on a regular basis, making them a
less-than-ideal solution. NiMH batteries are a better choice, but are
considerably more expensive than lead-acid. Lithium-ion battery powered vehicles such as the Venturi Fetish have recently demonstrated excellent performance and range, but they remain very expensive.
Bioalcohol / Ethanol
An early poster, prior to flexi-fuel engines, promoting alcohol fuel
warns Brazilians not to mix standard petrol with alcohol fuel, and not
to use alcohol in un converted engines.
The use of alcohol as a fuel for internal combustion engines, either
alone or in combination with other fuels, has been given much attention
mostly because of its possible environmental and long-term economical
advantages over fossil fuel.
Both ethanol and methanol have been considered for this purpose.
While both can be obtained from petroleum or natural gas, ethanol may
be the most interesting because many believe it to be a renewable
resource, easily obtained from sugar or starch in crops and other
agricultural produce such as grain, sugarcane or even lactose. Since
ethanol occurs in nature whenever yeast happens to find a sugar
solution such as overripe fruit, most organisms have evolved some
tolerance to ethanol, whereas methanol is toxic. Other experiments
involve butanol, which can also be produced by fermentation of plants.
When alcohol fuel is mixed into gasoline, the result is known as
gasohol and labelled with an 'E' followed by the percentage of Ethanol.
E10 is commonly found throughout the southern United States, E20 will
be mandated by the U.S. state of Minnesota by 2013. and E85
(containing 85% ethanol and just 15% of gasoline) is slowly becoming
available. E100 is straight ethanol, which is most widely used in Brazil and Argentina.
Use of pure ethanol and ethanol/gasoline mixtures is not without
problems however. Ethanol has the unfortunate property of slowly
decomposing certain rubber compounds such as are found in the fuel
lines and seals in vehicles produced before the mid 1980s. There are
claims that even E10 can have a significantly deleterious effect on
older vehicles and after prolonged use may cause dangerous fuel leaks
in affected cars. Because gasoline is more volatile than Ethanol, it
can be harder to start some engines using higher Ethanol percentages
than they were designed to use - especially when the engine is cold -
and even modern vehicles may be unable to run more than 20% ethanol for
this reason. Because of the difficulty of starting engines using
ethanol, it is common practice in E100 countries such as Brazil
to have a small gasoline reservoir in addition to the normal fuel tank
with a switch to allow the driver to switch over to gasoline when the
car has difficulties starting on ethanol alone. Ethanol is also
electrically conductive (gasoline is an effective insulator) which can
cause problems with some early electric fuel pump designs and fuel tank sensors. Corrosion of magnesium and aluminium
parts is also a concern at higher ethanol percentages. Ethanol has less
energy per volume than gasoline so miles-per-gallon ratings with
ethanol mixtures are significantly worse than with pure gasoline -
although ethanol has a higher octane rating which is beneficial to high
compression ratio engines.
Many cars that currently use gasoline can run on ethanol,
a fuel made from plant sugars. Most cars that are designed to run on
gasoline are capable of running with up to 15% ethanol mixed into
gasoline. With a small amount of redesign, gasoline-powered vehicles
can run on ethanol concentrations as high as 85%. Most gasoline fuelled
vehicles can be modified to run on LPG
but there has been some concern that the ethanol-gasoline mixtures
prematurely wear down seals and gaskets. Theoretically, the lower
energy content of alcohol should lead to considerably reduced
efficiency and range when compared with gasoline. However, EPA testing
has actually shown only a 20-30% reduction in range. Therefore, if the
vehicle is capable of doing 750 kilometers on a 50 liter tank (15
kilometers per liter), its range would be reduced to approximately 600
kilometers (12 kilometers per liter). Measures are available to
increase this efficiency, such as different camshaft configurations,
altering the timing/spark output of the ignition, increasing
compression, or simply using a larger fuel tank.
In the United States, alcohol fuel was produced in corn-alcohol stills until Prohibition
criminalized the production of alcohol in 1919. Interest in alcohol as
an automotive fuel lapsed until the oil price shocks of the 1970s.
Reacting to the high price of oil and its growing dependence on
imports, in 1975 Brazil
launched a huge government-subsidized effort to manufacture ethanol
fuel (from its sugar cane crop) and ethanol-powered automobiles. These
ethanol-only vehicles were very popular in the 1980s, but became
economically impractical when oil prices fell - and sugar prices rose -
late in that decade. In recent years Brazil has encouraged the
development of flex-fuel automobiles,
where the owner can use any mixture of ethanol and gasoline based on
their individual cost and performance goals. In 2005, 70% of the cars
sold in Brazil were flex-fuel.
The main benefit of Diesel combustion engines is that they have a
50% fuel burn efficiency; compared with just 23% in the best gasoline
engines. This makes Diesel engines capable of achieving much better
fuel efficiency than gasoline vehicles.
Biodiesel is commercially available in most oilseed-producing states
in the United States. As of 2005, it is somewhat more expensive than
fossil diesel, though it is still commonly produced in relatively small
quantities (in comparison to petroleum products and ethanol). Many
farmers who raise oilseeds use a biodiesel blend in tractors and
equipment as a matter of policy, to foster production of biodiesel and
raise public awareness. It is sometimes easier to find biodiesel in
rural areas than in cities.
Some Diesel-powered cars can run with little or no modification on 100% pure biodiesel, a fuel that can be made from vegetable oils.
Vegetable oils tend to solidify in cold weather conditions so vehicle
modifications may be required in order to heat the fuel prior to use
under those circumstances. Modern low emission diesels (most often Euro
-3 and -4 compliant), typical of the current production in the European
industry, require extensive modification of injector system, pumps and
seals etc. due to the higher operating pressures. The result is
sensitive lubrication & sealing systems that bio diesel fuels do
not protect and may even attack. This reduces the market for bio
diesels as increasing numbers of new vehicles are not able to use it.
Compressed Biogas may be used for Internal Combustion Engines after
purification of the raw gas. The removal of H2O, H2S and particles can
be seen as standard producing a gas which has the same quality as
Compressed Natural Gas. The use of biogas is particularly interesting
for climates where the waste heat of a biogas powered power plant
cannot be used during the summer.
CNG Compressed Natural Gas
High pressure compressed natural gas, mainly composed of methane,
that is used to fuel normal combustion engines instead of gasoline.
Combustion of methane produces the least amount of CO2 of all fossil
fuels. Gasoline cars can be retrofitted to CNG and become bifuel NGV Natural gas vehicles
as the gasoline tank stays. You can switch between CNG and gasoline
during operation. Estimated over 5 million CNG vehicles running
A flexible-fuel vehicle or dual-fuel vehicle is an automobile or
truck (lorry) that can typically alternate between two sources of fuel.
A common example is a vehicle that can accept gasoline mixed with
varying levels of ethanol (gasohol). Some cars carry a natural gas tank
and one can switch from gasoline to gas.
North American vehicles from approximately 1980 onward can run on
10% ethanol/90% gasoline (e.g., E10) with no modifications. Prior to
1980, many cars imported into the United States contained rubber,
aluminium, and other materials that were generally non-compatible with
any ethanol in their fuel delivery systems, and these cars experienced
problems when E10 was first introduced. American made cars from the
late 1970s onward can run on E10 with no modifications. E10 fuel is
widely available. Going beyond 10% ethanol generally requires special
In the United States, many flexible-fuel vehicles can accept up to
85% ethanol (E85). The fuel mixture is automatically detected by one or
more sensors, and once detected, the ECU tunes the timing of spark
plugs and fuel injectors so that the fuel will burn cleanly in the
vehicle's internal combustion engine. Originally, sensors in both the
fuel-line and in the exhaust system were used for flexible fuel
vehicles. In recent years, manufacturers have instead opted to use only
sensors in the exhaust manifold, before the catalytic converter, and to
eliminate the fuel inline sensor. As E85 is more corrosive, special
fuel lines are also required. Some manufacturers also required a
different motor oil be used, but even this requirement is now dropped
for all but one manufacturer.
A hybrid vehicle uses multiple propulsion systems to provide motive
power. This most commonly refers to gasoline-electric hybrid vehicles,
which use gasoline (petrol) and electric batteries for the energy used
to power internal-combustion engines (ICEs) and electric motors. These
powerplants are usually relatively small and would be considered
"underpowered" by themselves, but they can provide a normal driving
experience when used in combination during acceleration and other
maneuvers that require greater power.
The Toyota Prius
is one of the world's first commercially mass-produced and marketed
hybrid automobiles. Manufactured by Toyota, the Prius first went on
sale in Japan in 1997. The car was introduced to the worldwide market
in 2000 and almost 160,000 units had been produced for sale in Japan,
Europe, and North America as of the end of 2003.
The Honda Insight
is a 2-seater hatchback hybrid automobile manufactured by Honda. It was
the first mass-produced hybrid automobile sold in the United States,
introduced in 1999, and produced until 2006. Honda now offers the Civic as an optional hybrid.
Pedal Assisted Electric Hybrid Vehicle
In very small vehicles, the power demand decreases, so human power
can be employed to make a significant improvement in battery life. Two
such commercially made vehicles are the Sinclair C5 and the TWIKE.
A hydrogen car is an automobile which uses hydrogen as its primary
source of power for locomotion. These cars generally use the hydrogen
in one of two methods: combustion or fuel-cell conversion. In
combustion, the hydrogen is "burned" in engines in fundamentally the
same method as traditional gasoline cars. In fuel-cell conversion, the
hydrogen is turned into electricity through fuel cells which then
powers electric motors. With either method, the only byproduct from the
spent hydrogen is water.
A small number of prototype hydrogen cars currently exist, and a
significant amount of research is underway to make the technology more
viable. The common internal combustion engine, usually fueled with gasoline (petrol) or diesel liquids, can be converted to run on gaseous hydrogen. However, the most efficient use of hydrogen involves the use of fuel cells and electric motors instead of a traditional engine. Hydrogen reacts with oxygen inside the fuel cells, which produces electricity
to power the motors. One primary area of research is hydrogen storage,
to try to increase the range of hydrogen vehicles while reducing the
weight, energy consumption, and complexity of the storage systems. Two
primary methods of storage are metal hydrides and compression. Some
believe that hydrogen cars will never be economically viable and that
the emphasis on this technology is a diversion from the development and
popularization of more efficient hybrid cars and other alternative
High speed cars, buses, motorcycles, bicycles, submarines, and space rockets
already run on hydrogen, in various forms. There is even a working toy
model car that runs on solar power, using a reversible 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.
BMW's Clean Energy internal combustion hydrogen car has more power
and is faster than hydrogen fuel cell electric cars. A limited series
production of the 7 Series Saloon was announced as commencing at the
end of 2006. A BMW hydrogen prototype (H2R) using the driveline of this
model broke the speed record for hydrogen cars at 300 km/h (186 mi/h),
making automotive history. Mazda has developed Wankel engines to burn
hydrogen. The Wankel uses a rotary principle of operation, so the
hydrogen burns in a different part of the engine from the intake. This
reduces pre-detonation, a problem with hydrogen fueled piston engines.
However the major car companies like DaimlerChrysler and General
Motors Corp, are investing in the slower, weaker, but more efficient
hydrogen fuel cells instead. Hydrogen fuel cells run directly on
hydrogen fuel, or on hydrogen produced in the vehicle from reforming
methane or gasoline (this from petroleum), or natural ethanol, while
hydrogen internal-combustion cars run on hydrogen only.
Liquid Nitrogen car
Liquid nitrogen (LN2) is a method of storing energy. Energy is used
to liquify air, and then LN2 is produced by evaporation, and
distributed. LN2 is exposed to ambient heat in the car and the
resulting nitrogen gas can be used to power a piston or turbine engine.
The maximum amount of energy that can be extracted from 1 kg of LN2 is
213 W-hr or 173 W-hr per liter, in which a maximum of 70 W-hr can be
utilized with an isothermal expansion process. Such a vehicle can
achieve ranges similar to that of gasoline with a 350 liter (90 gallon)
tank. Theoretical future engines, using cascading topping cycles, can
improve this to around 110 W-hr/kg with a quasi-isothermal expansion
process. The advantages are zero harmful emissions and superior energy
densities than compressed air, and a car powered by LN2 can be refilled
in a matter of minutes.
LPG or Autogas
LPG or liquified petroleum gas
is a low pressure liquified gas mixture composed mainly of propane and
butane which burns in conventional gasoline combustion engines with
less CO2 than gasoline. Gasoline cars can be retrofitted to LPG aka
Autogas and become bifuel vehicles as the gasoline tank stays. You can
switch between LPG and gasoline during operation. Estimated 10 million
vehicles running worldwide.
A solar car is an electric vehicle powered by solar energy obtained
from solar panels on the car. Solar cars are not a practical form of
transportation; insufficient power falls on the roof of a practically
sized and shaped vehicle to provide adequate performance. They are
raced in competitions such as the World Solar Challenge and the North
American Solar Challenge. These events are often sponsored by
Government agencies such as the United States Department of Energy keen
to promote the development of alternative energy technology such as
solar cells and electric vehicles. Such challenges are often entered by
universities to develop their students engineering and technological
skills as well as motor vehicle manufacturers such as GM and Honda.
The North American Solar Challenge
is a solar car race across North America. Originally called Sunrayce,
organized and sponsored by General Motors in 1990, it was renamed
American Solar Challenge in 2001, sponsored by the United States
Department of Energy and the National Renewable Energy Laboratory.
Teams from universities in the United States and Canada compete in a
long distance test of endurance as well as efficiency, driving
thousands of miles on regular highways.
the name of a series of manned solar powered vehicles that won the
World solar challenge in Australia three times in a row, in 2001 (Nuna
1 or just Nuna), 2003 (Nuna 2) and 2005 (Nuna 3). The Nunas are built
by students of the Delft University of Technology.
The World solar challenge
is a solar powered car race over 3021 km through central Australia from
Darwin to Adelaide. The race attracts teams from around the world, most
of which are fielded by universities or corporations although some are
fielded by high schools.
A steam car is a car that has a steam engine. Wood, coal, ethanol, or others can be used as fuel. The fuel is burned in a boiler and the heat converts water into steam. When the water turns to steam, it expands. The expansion creates pressure. The pressure pushes the pistons back and forth. This turns the driveshaft to spin the wheels forward. It works like a coal-fueled steam train, or steam boat. The steam car was the next logical step in independent transport.
Steam cars take a long time to start, but some can reach speeds over 100 mph (161 km/h) eventually.
A steam engine uses external combustion, as opposed to internal combustion. Gasoline-powered cars are more efficient at about 25-28% efficiency. In theory, a combined cycle steam engine in which the burning material is first used to drive a gas turbine can produce 50% to 60% efficiency. However, practical examples of steam engined cars work at only around 5-8% efficiency.
The best known and best selling steam-powered car was the Stanley Steamer. It used a compact fire-tube boiler under the hood to power a simple two-piston engine which was connected directly to the rear axle. Before Henry Ford
introduced monthly payment financing with great success, cars were
typically purchased outright. This is why the Stanley was kept simple;
to keep the purchase price affordable.
Steam produced in refrigeration also can be use by a turbine in other vehicle types to produce electricity, that can be employed in electric motors or stored in a battery.
Steam power can be combined with a standard oil-based engine to
create a hybrid. Water is injected into the cylinder after the fuel is
burned, when the piston is still superheated, often at temperatures of
1500 degrees or more. The water will instantly be vaporized into steam,
taking advantage of the heat that would otherwise be wasted.
can be used to power cars with ordinary internal combustion engines if
a wood gasifier is attached. This was quite popular during World War II in several European and Asian countries because the war prevented easy and cost-effective access to oil.
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