LPG is a viable alterna tive gaseous fuel (also known as ''Auto gas'') which is a gas
product of petroleum refining primarily consisting of propane,
propylene, butane and other light hydrocarbons [7-9].The engine, which uses conventional diesel fuel and
LPG fuel, is referred to as 'LPG-Diesel dual fuel engine'.In contrast, the low cetane number of LPG makes it difficult
to be used in large proportions in compression ignition
engines, mainly due to high cyclic variation [10,11,101].LPG has high calorific
value compared to other gaseous fuels and also it has high
octane number but a low cetane number.The high octane
number of LPG makes it suitable for spark ignition engines.Hence it can be used in the CI engine in the dual fuel mode
only and in this mode it has been extensively studied.So, storage and transportation of
LPG is easier than other gaseous fuels.It can
be liquefied in a low pressure range of 0.7-0.8 Mpa at
atmospheric temperature.It leads
to better performance, low particulate and smoke emissions
[12].