An Assessment About the Reasons of NOx Rise in Biodiesel’s Exhaust Emissions

Mustafa Çanakçı

Department of Mechanical Education,
Kocaeli University, Izmit, Kocaeli, Turkey

Hüseyin Şanlı

Department of Automotive, Yeniköy Vocational HighSchool,
Kocaeli University, Yeniköy, Kocaeli, Turkey


“Biodiesel” is the name used for fatty acid alkyl monoesters produced from renewable feedstocks such as vegetable oils and animal fats. Biodiesel is an environmentally friendly alternative fuel. Although important decreases are observed in biodiesel exhaust emissions, compared with petroleum based diesel fuel, its NOx emission raises. When we consider that biodiesel’s heating value is less and cetane number is higher than that of diesel fuel, higher NOx emission is surprising. In this work, the fuel properties of biodiesel such as cetane number, compressibility, and oxygen content, which are effective on NOx formation, are discussed.

Keywords: biodiesel, NOx emission, fuel properties, combustion