10
Alternative Fuels for Transportation
compatibility with the use of two fuels. Switch over of operation
from alternative fuel mode to conventional fuel mode should be
done easily.
The search for an alternative fuel has produced a long list of new candidates
and a series of arguments, which support and project their characteristics.
Suitability of each of these fuels for internal combustion engines has been
under investigation throughout the world. Some of the important fuels are
listed here:
i. Alcohols (methanol and ethanol)
ii. Vegetable oils and biodiesel
iii. Gaseous fuels (natural gas, hydrogen, and liquefied petroleum gas)
iv. Ethers
v. Electric/fuel cell/hybrid vehicles
vi. Future fuels
1.4.1 Alcohols
Alcohols are considered as a substitute or additive component for gasoline as
they possess a higher octane number. The move toward unleaded fuels produced excessive exhaust valve wear in gasoline engines. This problem was
solved by incorporating hardened valve seats and satellite coating of valves.
These lead to an increase in the use of alternative fuels, particularly methyl
tertiary butyl ether (MTBE), methanol/ethanol blends with gasoline because
of their higher octane number.
1.4.1.1 Methanol
Methanol was used as an automobile fuel during the 1930s to replace/
supplement gasoline supplies in high-performance engines. With the U.S.
Government’s mandatory phase-out of lead as a gasoline octane additive, a
low concentration of methanol is found to be a good nonmetallic substitute. MTBE replaced methanol and tertiary butyl alcohol for a short while.
However, the use of MTBE phased out due to the environmental concern.
With the advent of flexi-fuel vehicles (FFV) in the 1990s, the methanol
became a prime candidate for use in vehicles because of its lower emission
characteristics and high-octane rating. To solve the cold-start problems in
methanol, a percentage of gasoline is added. Blends of 15% gasoline and 85%
of methanol are called M85. The FFV vehicles are also able to operate on
gasoline, methanol, and their blends. For the adjustment of air–fuel ratio and
spark timing there is a sensor in the fuel line that measures the percentage of
methanol in the gasoline and gives the information to the engine computer.
Though it is a commercial success, methanol has not become the competitor
Alternative Fuels for Transportation
compatibility with the use of two fuels. Switch over of operation
from alternative fuel mode to conventional fuel mode should be
done easily.
The search for an alternative fuel has produced a long list of new candidates
and a series of arguments, which support and project their characteristics.
Suitability of each of these fuels for internal combustion engines has been
under investigation throughout the world. Some of the important fuels are
listed here:
i. Alcohols (methanol and ethanol)
ii. Vegetable oils and biodiesel
iii. Gaseous fuels (natural gas, hydrogen, and liquefied petroleum gas)
iv. Ethers
v. Electric/fuel cell/hybrid vehicles
vi. Future fuels
1.4.1 Alcohols
Alcohols are considered as a substitute or additive component for gasoline as
they possess a higher octane number. The move toward unleaded fuels produced excessive exhaust valve wear in gasoline engines. This problem was
solved by incorporating hardened valve seats and satellite coating of valves.
These lead to an increase in the use of alternative fuels, particularly methyl
tertiary butyl ether (MTBE), methanol/ethanol blends with gasoline because
of their higher octane number.
1.4.1.1 Methanol
Methanol was used as an automobile fuel during the 1930s to replace/
supplement gasoline supplies in high-performance engines. With the U.S.
Government’s mandatory phase-out of lead as a gasoline octane additive, a
low concentration of methanol is found to be a good nonmetallic substitute. MTBE replaced methanol and tertiary butyl alcohol for a short while.
However, the use of MTBE phased out due to the environmental concern.
With the advent of flexi-fuel vehicles (FFV) in the 1990s, the methanol
became a prime candidate for use in vehicles because of its lower emission
characteristics and high-octane rating. To solve the cold-start problems in
methanol, a percentage of gasoline is added. Blends of 15% gasoline and 85%
of methanol are called M85. The FFV vehicles are also able to operate on
gasoline, methanol, and their blends. For the adjustment of air–fuel ratio and
spark timing there is a sensor in the fuel line that measures the percentage of
methanol in the gasoline and gives the information to the engine computer.
Though it is a commercial success, methanol has not become the competitor