Performance of an SI Engine Operating on a Dual Gasoline and Liquefied Petroleum Gas (LPG) Fuel

Abstract The economic growth of nations often coincides with an increase in energy consumption. As countries develop, their energy demand naturally rises. In Nigeria, this demand is primarily met with conventional fossil fuels, which have resulted in environmental degradation and greenhouse gas emissions. In response to the Paris Agreement of 2015, which seeks to limit global warming, many nations made pledges and commitments towards cleaner energy options to help mitigate climate change. This article presents experimental investigations conducted on a mini-internal combustion engine test bed commonly used for power generation in Nigeria. The test bed is a single-cylinder, two-stroke, single overhead camshaft (SOHC), 6.5 HP spark ignition (SI) gasoline engine, typically used as an off-grid backup power source for low- and middle-income households. The engine was slightly modified to run on dual liquefied petroleum gas (LPG) and gasoline fuel using a dual-fuel carburetor. Our findings reveal that gasoline produced marginally better operational mean effective pressure (OMEP) of about 13.26 kPa and engine torque (and power), 49 RPM relative to LPG, with OMEP of 12.24 kPa and 45 RPM, respectively. LPG, on the other hand, outperformed gasoline in terms of engine efficiency, specific fuel consumption, and energy pricing. Despite the engine test bed being designed and optimized for gasoline fuel, LPG showed significant promise as a viable fuel in a gasoline SI engine.