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India is an agrarian country and produces a considerable amount of
agricultural waste and has vast reserve of high ash coal and
low-value biomass, which can be used to produce methanol, which can
be a potential fuel for diesel locomotives. Methanol has emerged as
a potential alternative fuel globally because it can be prepared
from high ash coal and low-value biomass, via gasification. It can
also be prepared from natural gas, atmospheric CO2, and CO2 emitted
by thermal power plants. CO2 extraction from atmosphere or thermal
power plants can also reduce India’s contribution to GHG emissions.
Methanol is a high octane and low cetane fuel with higher
auto-ignition temperature (470°C), as compared to mineral diesel
(250-450°C). Therefore, it is difficult to auto-ignite methanol in
CI engines without external assistance. It is therefore a preferable
fuel for SI engines. However, Methanol can also be used in CI
engines with diesel pilot injection, which has relatively higher
cetane number. Different methods for utilizing methanol in CI engine
are: (i) Introduction of methanol-diesel blend into the engine
cylinder via a single injector. Single injector is required for
injecting diesel-methanol blend, which is an advantage of this method.
However, this method limits the quantity of methanol injected into
CI engine because methanol separates from diesel if it’s
concentration is more than 10% (v/v). In addition, an emulsifier is
needed in case blending of higher methanol fraction is targeted.
(ii) Port injection of methanol with direct injection of diesel.
(iii) Methanol injected directly into the cylinder with diesel pilot
injection. In this approach, diesel pilot is used for igniting
methanol. This method can be implemented in the locomotive engine in
two different ways. First, use two separate injectors for
introduction of methanol and diesel. Second, use a co-axial
injector, which is able to introduce both methanol and diesel.
Current research is focusing on the development of Co-Axial injector
by following both simulation (1-D and 3-D )and experimental routes.
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