Emission analysis of combustion of cashew nutshell biodiesel in a toroidal combustion chamber: an experimental study

Fossil fuels dominate the transportation industry and contribute to a major influence on global energy consumption. However, there is a need for sustainable and renewable alternatives to conventional fossil fuels to create significant health hazards for the ecological system. This study investigates the potential of waste cashew nut shell liquid (CSNL) biodiesel blends as a sustainable alternative fuel for compression ignition (CI) engines. The research focuses on the impact of various CNSL blends on combustion, engine performance, and emission characteristics in a CI engine equipped with a toroidal combustion chamber (TCC) and the results are compared with the normal piston (NP) geometry arrangement. The experimental results show that at a maximum brake power (BP) of 4.9 kW, TCC exhibited a 1.89% higher brake thermal efficiency (BTE) than the NP arrangement when powered by D80-CNSL20 fuel, and 7.14% lower brake specific fuel consumption was observed for the same configurations. Fewer emission levels of 10.71% hydrocarbon (HC), 4.85% carbon monoxide (CO), and 12.71% smoke were recorded in TCC compared to the NP arrangement. Furthermore, TCC released 4.40% higher HRR than NP and developed 26.92% higher pressure than NP. However, the higher heat release rate (HRR) observed in TCC results in slightly higher oxides of nitrogen (NO_x) emission. Thus, based on the results, the authors conclude that CSNL blends minimize the emission level and the use of TCC enhances the engine performance.