11
Fuels and Trends
of gasoline because of its higher cost. Currently, methanol is again considered
for fuel cell vehicles; that is, methanol is used as fuel to derive the hydrogen
for the operation of fuel cells.
1.4.1.2 Ethanol
Ethyl alcohol, commercially known as ethanol, possesses a number of characteristics favoring its use as an automobile fuel. Nikolaus August Otto, the
German inventor of the internal combustion engine, conceived his invention
to run on ethanol. Ethanol is a by-product in the production of sugar. It can
be considered a renewable fuel as it is produced from the sources where
there is a potential for greenhouse gas emissions abatement. It depends on
the production process, especially the nature of energy inputs used in distillation and other phases. The use of ethanol in spark ignition engines started
from the 1950s in countries like United States, Germany, and France. During
World War I and World War II, ethanol was used as a substitute fuel for commercial as well as military vehicles. Currently, it is blended with gasoline in
most of the countries and it is a major fuel in Brazil.
A close observation on its properties shows that it can be considered as
a suitable automobile fuel. The autoignition temperature of ethanol is significantly higher than gasoline and this makes ethanol less susceptible to
ignition. Presently, the focus is on ethanol for the replacement of MTBE and
oxygenates in the gasoline. At present, ethanol is blended with gasoline for
improving the octane number of gasoline for eliminating the blending of
MTBE. Ethanol molecules contain oxygen and therefore, it allows the engine
to completely combust the fuel, resulting in less emission of carcinogenic
gases like carbon monoxide, NO x , and so on. Moreover, it reduces the particulate concentration and greenhouse gas effect.
Though most of the work has been done on ethanol as a substitute for
gasoline fuel, ethanol is also a suitable alternative fuel for diesel engines.
Vaporizing ethanol in a naturally aspirated engine is an inexpensive way of
using ethanol in the diesel engine and replacing about 60% diesel consumption. For higher blends of ethanol ( > 20%), high concentrations of additives
are needed to stabilize the mixture or attain the required cetane number.
The higher percentage of ethanol in diesel requires a double-injection device
or so-called dual fuel or fumigation systems. Gaseous pollutants and combustion noise levels could be significantly reduced, but the complexity to
control these devices is restricted. However, use of 100% ethanol in diesel
engines requires some modification in the engine fuel system.
1.4.2 Vegetable Oils and Biodiesel
Dr. Rudolf Diesel, inventor of the diesel engine, has demonstrated that his
engine ran on peanut oil. With the advent of low-cost crude oil, appropriate crude oil fractions were refined to serve as fuel and hence diesel engine
Fuels and Trends
of gasoline because of its higher cost. Currently, methanol is again considered
for fuel cell vehicles; that is, methanol is used as fuel to derive the hydrogen
for the operation of fuel cells.
1.4.1.2 Ethanol
Ethyl alcohol, commercially known as ethanol, possesses a number of characteristics favoring its use as an automobile fuel. Nikolaus August Otto, the
German inventor of the internal combustion engine, conceived his invention
to run on ethanol. Ethanol is a by-product in the production of sugar. It can
be considered a renewable fuel as it is produced from the sources where
there is a potential for greenhouse gas emissions abatement. It depends on
the production process, especially the nature of energy inputs used in distillation and other phases. The use of ethanol in spark ignition engines started
from the 1950s in countries like United States, Germany, and France. During
World War I and World War II, ethanol was used as a substitute fuel for commercial as well as military vehicles. Currently, it is blended with gasoline in
most of the countries and it is a major fuel in Brazil.
A close observation on its properties shows that it can be considered as
a suitable automobile fuel. The autoignition temperature of ethanol is significantly higher than gasoline and this makes ethanol less susceptible to
ignition. Presently, the focus is on ethanol for the replacement of MTBE and
oxygenates in the gasoline. At present, ethanol is blended with gasoline for
improving the octane number of gasoline for eliminating the blending of
MTBE. Ethanol molecules contain oxygen and therefore, it allows the engine
to completely combust the fuel, resulting in less emission of carcinogenic
gases like carbon monoxide, NO x , and so on. Moreover, it reduces the particulate concentration and greenhouse gas effect.
Though most of the work has been done on ethanol as a substitute for
gasoline fuel, ethanol is also a suitable alternative fuel for diesel engines.
Vaporizing ethanol in a naturally aspirated engine is an inexpensive way of
using ethanol in the diesel engine and replacing about 60% diesel consumption. For higher blends of ethanol ( > 20%), high concentrations of additives
are needed to stabilize the mixture or attain the required cetane number.
The higher percentage of ethanol in diesel requires a double-injection device
or so-called dual fuel or fumigation systems. Gaseous pollutants and combustion noise levels could be significantly reduced, but the complexity to
control these devices is restricted. However, use of 100% ethanol in diesel
engines requires some modification in the engine fuel system.
1.4.2 Vegetable Oils and Biodiesel
Dr. Rudolf Diesel, inventor of the diesel engine, has demonstrated that his
engine ran on peanut oil. With the advent of low-cost crude oil, appropriate crude oil fractions were refined to serve as fuel and hence diesel engine