Improving the performance of a diesel engine using nanomaterials and chlorella vulgaris microalgae blends assisted with biogas

Microalgae-based fuel has attracted attention as a green energy source for the transportation sector owing to its high suitability, availability, and rapid growth rate. Furthermore, algae consume carbon dioxide to produce fuel, and indirectly reduce global warming. This study predicts the effects of microalgae biofuel blends assisted by biogas and nanoparticles on diesel engine performance, combustion, and emission characteristics across various engine speeds for the first time. Biogas, which is rich in carbon monoxide and hydrogen, passed through the intake manifold at a constant flow rate of 10 L per minute. Al₂O₃ nanoparticles were dispersed in the biodiesel at a concentration of 100 ppm. The inclusion of hydrogen enhanced both the brake power and brake thermal efficiency of the engine irrespective of engine speed. A blend of both biogas and nanoparticles resulted in less specific fuel consumption than Chlorella vulgaris biodiesel blends owing to lower viscosity and higher energy ratio. However, the inclusion of nanoparticles reduced the in-cylinder pressure. In terms of emissions, all the microalgae blends exhibited reduced formation of carbon monoxide, carbon dioxide, and hydrocarbon compared to diesel. However, the formation of nitrogen of oxides in 20% microalgae blend A20 was higher than that in diesel and 20% microalgae blend with nanoparticle (AB20 N). Owing to the presence of CO in the biogas, the total accumulation of CO and CO₂ was higher for AB20 N than for other fuel blends. From the above analysis, it is clear that CO can be used in conjunction with hydrogen to assist the internal combustion process.