Effects of antioxidant additives on engine performance and exhaust emissions of a diesel engine fueled with canola oil methyl ester–diesel blend

• BHA, BHT, TBHQ, EHN synthetic antioxidants were employed in the study.
• Antioxidant additives are a promising candidate for improving cetane number, oxidation stability and decreasing NOx emissions
• Cetane number improving efficiency of the antioxidants was ordered as EHN>BHA>BHT>TBHQ.
• Formation of CO emissions has been increased with addition of each of the antioxidants to B20.

An experimental investigation has been carried out to analyze the effect of antioxidants on engine performance and exhaust emissions of a diesel engine fueled with B20 (20 vol.% canola oil methyl ester and 80 vol.% diesel fuel blend). The four synthetic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butylhydroquinone (TBHQ) and 2-ethylhexyl nitrate (EHN), were tested on a Land Rover turbocharged direct injection (TDI) 110 type diesel engine with water cooled, 4-cycl and 4-cylinder. The addition of antioxidants to B20 did not cause any negative effect on basic fuel properties of B20. According to engine performance test results, brake specific fuel consumption (BSFC) of B20 with antioxidants decreased compared to those of B20 without antioxidants. A 1000 ppm concentration of TBHQ was optimal as BSFC values were considerably reduced (10.19%) in the whole engine speeds when compared to B20. EHN antioxidant with B20 presented the best mean oxides of nitrogen (NOx) with a reduction of 4.63%. However, formation of carbon monoxide (CO) emissions has been increased with addition of each of the antioxidants to B20.