Combustion of ethanol-vegetable oil blends in diesel engines

Vegetable oils, utilized in transportation primarily as a feedstock for biodiesel, can be also combusted in diesel engines in their neat, non-esterified form. Given the high viscosity and high flash point of vegetable oils, they need to be used heated, in a warm engine, operated at moderate to high loads. This study examines the possibility to reduce the viscosity and the flash point of vegetable oils by blending with a small quantity of ethanol. Experimental work carried on a typical tractor diesel engine Zetor 1505, fueled by heated fuel-grade rapeseed oil in its neat form and with 10 % by weight of commercial E85 fuel containing 85% ethanol, reveals emissions benefits (decrease in HC, CO and NOx) at higher loads, where the combustion of rapeseed oil is not considered to be problematic. At low loads, where rapeseed oil combusts poorly, the addition of ethanol further delayed the combustion and increased both HC and CO emissions. Addition of ethanol, while in some ways possibly beneficial, thus does not appear to improve the problematic combustion of vegetable oils at low loads.

Subject(s)

Combustion, Diesel engines, Emissions, Ethanol, Rapeseed oil, Vegetable oil

Item identifier

https://dspace.tul.cz/handle/15240/16412

ISSN

1210-3306

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