Multi-Fuel Performance of a Petrol Engine for Small Scale Power Generation

With limited power production and management resources Bangladesh is struggling to meet the increasing energy demand of its large population. Small-scale power generators run by petrol engines are widely being used to cope up with the frequent power failures. Engine performance with three alternative fuels - domestic line supply of Natural Gas (NG), Liquefied Petroleum Gas (LPG) and Bio-gas were studied in a 1.5 kW portable electric generator run by a petrol engine. In order to retain instant interchangeability to petrol fuel and minimum alteration cost, the engine modifications were kept to a minimum. The engine running with natural gas and LPG showed improved performance regarding - fuel economy, overall efficiency and significantly better exhaust emission characteristics, compared to running on petrol. Maximum output power was reduced by 10-15% with natural gas and LPG, while using bio-gas the reduction was more significant. For all cases the alternative fuel was introduced into the intake manifold using natural aspiration of the engine. Requirement of controlling gas flow introduced some added complexity. Taking the economical and environmental benefits into account, natural gas was found to be the most potential alternative fuel for small-scale power generation using SI engines. LPG at the existing market prices gave only a small economic benefit while use of bio-gas could be viable only for specific locations. The results may have significance in small-scale power generation in - small hotel-restaurants with line supply of natural gas, households using LPG cylinders for cooking and agricultural and poultry firms using bio-gas plants.