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As emission norms are becoming stringent day by day and in the view
of energy security, it is very much essential and necessary to find
alternate solutions. Dimethyl Ether is an alternative fuel for
conventional diesel engine similar to as Alcohol is for petrol
engine. Dimethyl Ether is a simplest form of ether with chemical
formula CH3OCH3. It can be synthesis indirectly by dehydration of
methanol or directly from natural gas. As DME does not have any C-C
bond it is said that exhaust emission would be free of soot and NOx
can be eliminated by Exhaust Gas Recirculation, which are the two
main exhaust emission constituents for diesel engines. Challenges
for using DME as a fuel are mainly, handling the liquefied gas at a
pressure above its vapour pressure(5bar @NTP) to maintain liquid
state through out the fuel injection system, both in high pressure
line and low pressure line with leak proof joints and mixing
additives with DME in pressurized condition to lubricate the fuel
injection pump. Other modification that might be incorporated are:
changes in design of fuel injection system such as injection angle
and nozzle diameter to inject the high vapor pressure DME having low
calorific value compared to conventional diesel. Currently in our
laboratory to modify the design of mechanical fuel injection system
of existing 49hp tractor engine, macroscopic and microscopic spray
study is being carried out with a high speed CCD camera (Photron,
FastCam SA 1.1) and Phase Doppler Interferometry(Artium, PDI-300
MD). Further the low pressure line suitable for liquid DME supply to
the engine is also being developed. This project also has a scope to
run the engine in transient dynamometer for checking transient load
conditions, combustion analyzing, exhaust gas emission and
particulate measurements. |
