Abstract:
Considering the difficulty in meeting the ever increasing demand of energy as well as
greater concern regarding the environment, searches for possible alternative energy
resources are being carried out throughout the developed world as well as in many
developing countries. Conventional fossil fuel run internal combustion engines are one
of the large sources of environmental pollution. Natural gas is one of the most potential
alternative fuels that can be used in petrol or diesel run engines of different types, with
different degree of engine modifications. Small scale petrol engine run generators are
widely used to cope up with frequent power failures in Bangladesh. This research
concerns the use of domestic line supply of natural gas as an alternative fuel in a small
spark ignition engine run portable electric generator of 1.5kW rated capacity. To retain
instant inter-chanagability to petrol fuel and minimum alteration cost, the engine
modifications were intended to be kept as minimum as possible. Such an engine could
have potential applications in - households, community halls and small commercial units.
Smooth engine operation with natural gas was achieved with small alterations to the air
intake structure. The engine run with natural gas showed improved performance
regarding - fuel economy, overall efficiency and significantly better exhaust emission
characteristics, compared to the petrol counterpart. On the other hand the maximum load
carrying capacity was found to be limited to some extent (about 85% of rated) and the gas
now controlling requirement introduced some added complexity. A simple and cheap.
single step gas flow regulating device was designed for running the engine near the rated
capacity. This provided smooth engine operations from 50-85% of the rated capacity.
Taking the economical and environmental benefits into account natural gas could be a
very potential alternative fuel for small scale power generation using Sl engines.
