Feasibility study on raw Simarouba glauca oil as an alternate fuel in a diesel engine and comparative assessment with its esterified oil

Abstract

In this work, the influence of raw Simarouba glauca Seed Oil (SSO) and its biodiesel (SSOB) is studied in terms of its performance, combustion and emissions of a four-stroke, single-cylinder, direct injection and water-cooled diesel engine. 10 different fuel blends are used such as R10 (10% SSO + 90% diesel), R20, R40, R60, R100 (100% SSO), B10 (10% SSOB + 90% diesel), B20, B40, B60 and B100 (100% SSOB), and they are compared with the diesel. The experiment is carried out at a constant speed of 1800 rpm and a compression ratio of 17.5:1 with four loading conditions of 0, 1.75, 3.5 and 5 kW. The results have shown a slight loss in the performance and inferior combustion on higher blends. At higher loads, Brake Thermal Efficiency (BTE) of SSO and SSOB blends have decreased in the range of 4.11–9.00% and 0.96–7.53%, respectively, while the Brake Specific Energy Consumption (BSEC) of SSO and SSOB blends get increased when compared to the neat diesel. For SSO blends, the Net Heat Release Rate (NHRR) and Cumulative Heat Release Rate (CHRR) are in the range of 15–48% and 1.8–15.8% which is lower than the diesel, respectively. On the other hand, SSOB blends have proved with higher BTE, NHRR and CHRR than the respective SSO blends. NOx emissions of SSO blends are in the range of 9.22–20% which is lower than that of the pure diesel at higher loads. Meanwhile, HC and CO emissions of SSO blends are slightly higher than the pure diesel and SSOB blends, respectively. It is due to the reasons such as reduced viscosity, better atomisation, and enhanced heating value of SSOB blends after the esterification process compared to the SSO blends. From the investigation, it has been concluded that the Compression Ignition (CI) engine could run satisfactorily on raw oil blends without any alterations in the engine. However, the performance and emission levels are inferior to the Bio-Diesel (BD) blends.