Effect of antioxidant additives on the performance and emission characteristics of a DICI engine using neat lemongrass oil–diesel blend

• Use of antioxidants is an effective technique for improving oxidation stability.
• Two antioxidants such as BHA and BHT were used in the study.
• BHA exhibits better oxidation stability and reduction of NOx emission than BHT.
• CO, HC and Smoke emissions increase with the addition of antioxidants BHA and BHT.

In this experimental investigation, the effect of antioxidant additives on the performance and the exhaust emissions of a computerized single cylinder direct injection compression ignition (DICI) engine has been studied. The test fuel used in this study was neat lemongrass oil (LGO)–diesel blend. Neat lemongrass oil is a new alternate fuel used in a diesel engine. Antioxidant additives butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were individually dissolved at concentrations of 500, 1000, 2000 ppm by weight in LGO25 blend (75% diesel + 25% neat lemongrass oil by % volume). The emission results showed a significant reduction of NOx at the expense of increasing CO, Smoke and HC emissions. The addition of BHA at 2000 ppm with LGO25 exhibited a maximum reduction of NOx by 11% than LGO25 without any antioxidant additives. The results showed that LGO25 with antioxidant additives produced an increase in Brake thermal efficiency (BTE) and decrease in exhaust gas temperature (EGT) and specific fuel consumption (BSFC). BHA antioxidant additive exhibits a better stability than BHT in LGO25 fuel. Thus, LGO25 with added antioxidants can be used in diesel engines without any modification.