Performance and Emission Evaluation in Dual-Fuel Engine Using Renewable Fuels for Pilot Injection

The non-availability of suitable alternative energy sources for automotive vehicles in the near future at an affordable price has been a global concern. A short-term measure that has attracted interest is the use of renewable bio-fuel substitutes that can be readily available, economical and friendly to the environment. The present study examines the performance of rapeseed methyl ester (RME), and pure vegetable oil (veg. oil), di-methyl ether (DME), or diesel as neat fuels or for pilot injection in a natural gas fuelled compression-ignition engine. With the DME operation, the corresponding range of power and peak pressure were much lower and the resultant specific fuel consumption higher than in the cases with diesel, and the bio-fuels. The emissions of oxides of nitrogen (NOx) and carbon dioxide (CO₂) were found to be lower when DME was used for pilot injection while carbon monoxide (CO) and unburnt hydrocarbon (uHC) were found to be higher than expected at all operating conditions compared to operation with diesel or bio-fuel pilot injection.