Performance and emission characteristics of CI engine using hydrogen enrichment in biodiesel blend with additives—A review

It is an irresistible argument that there is a requirement for sustainable resources for energy production as there is an enormous rise in demand for energy. Various sectors involve a wide range of energy consumption shares. Conventional fuels are exhaustible and can be replaced with sustainable substitutes, i.e., biofuels including bio-ethanol, biogas, and biodiesel. Recently, biodiesel has gained popularity due to the availability and affordability of feedstock. To extract biodiesel from vegetable oils, the transesterification process is widely used. Biodiesel blends can be used as a direct substitute in diesel engines, which may result in a slight reduction in hydrocarbons, carbon monoxide, and an increase in oxides of nitrogen. The performance parameters may increase or decrease depending on the blend type and calorific value. The objective of this review is to analyze the performance and emission characteristics of second and third-generation biodiesel blends enriched with hydrogen and to explore techniques for improvement such as the addition of additives. Research has shown that the addition of hydrogen improves combustion, resulting in increased brake thermal efficiency and reduced brake specific fuel consumption. Similarly, the inclusion of additives can reduce the production of oxides of nitrogen during combustion. In conclusion, biodiesel blends enriched with hydrogen and additives can offer improved performance, combustion, and emission characteristics. To meet energy demand sustainably and reduce reliance on conventional fuels, further research is necessary to ensure the long-term viability of biodiesel as a sustainable energy source.