Impacts of novel calotropis gigantea seed biodiesel usage as a fuel substitute along with various metal-oxide nanoparticles on the DICI engine characteristics

Abstract

Calotropis gigantea, commonly known as Indian milkweed, is a prevalent plant in Asia. It typically thrives in open and unused areas, often considered a weed. This plant produces flowers and fruits consistently throughout the year, exhibiting a continuous flowering and fruiting cycle. This research investigated the viability of Calotropis gigantea seed oil as a potential source intended for biodiesel manufacturing. The oil was obtained from Calotropis gigantea seeds using hexane extraction in the Soxhlet apparatus. The seeds were determined to contain 33.3 wt% of oil content. The process of biodiesel production involved conducting a transesterification reaction. Further, the produced biodiesel was blended with pure diesel and three different nanoparticles, Titanium dioxide (TiO₂), Chromium oxide (Cr₂O₃), and Silicon dioxide (SiO₂), to evaluate combustion performance, and emission characteristics of a single-cylinder diesel engine under various load conditions. Incorporating Cr₂O₃ nanoparticles into the CGSB20 biodiesel blend yielded significant improvements in BTE, coupled with BSFC reduction. Specifically, in the CGSB20 + Cr₂O₃ fuel mixture, BTE increased notably by 31.2 %, reaching a value of 0.33 g/kWh for BSFC. Similarly, for the CGSB20 + SiO₂ and CGSB20 + TiO₂ blends, BTE experienced enhancements of 29.2 % and 28.1 %, respectively, while BSFC values were lowered to 0.37 and 0.4 g/kWh. Furthermore, the unchanging dispersal of nanoparticles within the CGSB20 blend exhibited extraordinary cylinder pressure and HRR values, reaching 77 bar and 34.2 J/CA, respectively. The CGSB20+ Cr₂O₃ blend yielded favorable emissions outcomes. Specifically, CO, NOx, UHC, and smoke emissions were approximately 4.5 g/kWh, 725 ppm, 0.11 g/kWh, and 23.6 %, respectively.