In this study, engine performance on thermal factors for different biodiesels has been studied and compared with diesel fuel. Biodiesels were produced from Pongamia pinnata (PP), Calophyllum inophyllum (CI), waste cooking oil (WCO), and acid oil. Depending on their free fatty acid content, they were subjected to the transesterification process to produce biodiesel. The main characterizations of density, calorific range, cloud, pour, flash and fire point followed by the viscosity of obtained biodiesels were conducted and compared with mineral diesel. The characterization results presented benefits near to standard diesel fuel. Then the proposed diesel engine was analyzed using four blends of higher concentrations of B50, B65, B80, and B100 to better substitute fuel for mineral diesel. For each blend, different biodiesels were compared, and the relative best performance of the biodiesel is concluded. This diesel engine was tested in terms of BSFC (brake-specific fuel consumption), BTE (brake thermal efficiency), and EGT (exhaust gas temperature) calculated with the obtained results. The B50 blend of acid oil provided the highest BTE compared to other biodiesels at all loads while B50 blend of WCO provided the lowest BSFC compared to other biodiesels, and B50 blends of all biodiesels provided a minimum % of the increase in EGT compared to diesel.

In this experimental study, the performance of the diesel engine was analyzed for biodiesel derived from Calophyllum inophyllum. The impact of the addition of additives such as N-octanol and N-butanol with Calophyllum inophyllum biodiesel has been assessed. Impact of the application of hybrid N-octanol and N-butanol with biodiesel on emission profile used for the engine performance has also been demonstrated. Response surface analysis of alcohol additives-biodiesel blend was performed separately in this study for the engine efficiency and emission profile. A combination of N-octanol and N-butanol presented the highest brake thermal efficiency (BTE) and lowest carbon monoxide (CO) emission among the ternary blends of octanol. N-butanol-biodiesel blend presented the lowest hydrocarbon (HC) emission among the blends of N-butanol. N-octanol with 5 and 10% addition with biodiesel showed the lowest HC emissions among the blends of octanol. The response surface methodology (RSM) optimization revealed that the optimized thermal efficiency and emission were obtained at full load and minimum load, respectively. The addition of N-octanol hindered the emission at all loads, while N-butanol reduced it at higher loads. A strong correlation between the load and alcohol additives on the engine performance and emission profile has been obtained using the RSM optimization approach. The R-squared value obtained from the RSM was 0.92 and emission profile has been characterized.