Introduction
Ethanol fuel is ethanol (ethyl alcohol), the same type of alcohol found in
alcoholic beverages. It is most often used as a motor fuel, mainly as a biofuel
additive for gasoline. Most cars on the road today in the United States can
run on blends of up to 10 per cent ethanol, and the use of 10 per cent ethanol
gasoline is mandated in some US states and cities.
Bioethanol is a form of renewable energy that can be produced from
agricultural feedstocks. It can be made from very common crops such as sugar
cane, potato, manioc and corn. There has been considerable debate about how
useful bioethanol will be in replacing gasoline. Concerns about its production
and use relate to increased food prices due to the large amount of arable land
required for crops, as well as the energy and pollution balance of the whole cycle
of ethanol production, especially from corn. Recent developments with cellulosic
ethanol production and commercialisation may allay some of these concerns.
The need for automotive fuel is going to increase and, dependence of
internal combustion engine as a source for transport will continue with other
technological developments not posing any significant challenge to it. Among
the automobiles, there are two groups of their engines, based on:
1. Constant volume cycle which in practice is our gas engines and
alternatively called spark ignition engine. The fuel for this kind of
engine is gasoline cut of the crude oil.
2. Constant pressure cycle which in practice is diesel engine and
alternatively called compression ignition engine. The fuel for this
kind of engine is diesel a major fraction of crude oil distillation.
While the latter is used for all our heavy vehicles in railway transport, in
tractors, etc. the former is used for all light vehicles like cars, three wheelers
and two wheelers. Overall efficiency of a gasoline engine is lower than that
of a diesel engine; still it offers certain advantages due to its operation based
on gasoline, a light fuel. The advantages are in the form of quick start, fast
acceleration, no large emission of particulate matter (PM), no frequent major
engine overhauling requirement, etc. One of the major concerns of the diesel