Performance and Emissions of Diesel Fuels Containing Rapeseed Oil and the Characteristics of Evaporation and Combustion of Single Droplets

This investigation reports how rapeseed oil blended with gas oil influences performance and emissions of a small single cylinder DI diesel engine. The paper also investigates evaporation and combustion characteristics of the blended fuels with basic experiments of single droplet evaporation on a hot plate and suspended droplet combustion. The results showed that the smoke density decreased when the rapeseed oil addition rates, y are equal to or higher than 50%. Compared with gas oil operation, equal proportions of gas oil and rapeseed oil (y=50%) or fuels with lower rapeseed oil ratios showed quite similar BSEC (specific energy consumption) and combustion characteristics. The droplet evaporation experiments on a hot plate showed that the maximum boiling rate point of the blend with equal proportions of gas oil and rapeseed oil is about 720K, intermediate between the two fuels. The results of the suspended droplet combustion showed different trends in ignitability. The ignition lag of neat rapeseed oil droplets was much longer but equal proportions of gas oil and rapeseed oil showed good ignitability, like that of gas oil.