A progressive review on strategies to reduce exhaust emissions from diesel engine: Current trends and future options

This study examines modern methods to reduce emissions from diesel engines, with a focus on the role of advanced biofuels and innovative emission control techniques. The primary goal is to assess the potential of these solutions in lowering emissions and improving engine performance. Techniques like hydrogen injection and advanced biofuel blends are compared with conventional measures such as catalytic converters and particulate filters. Despite their widespread use, traditional methods often fall short in addressing the emission challenges of compression ignition (CI) engines. Research shows that hydrogen injection can lower NO_x emissions by up to 30% and particulate matter (PM) by nearly 25%, along with an improvement in thermal efficiency of 5–10%. Similarly, advanced biofuel blends, especially those derived from genetically modified microbes, have demonstrated a 15–25% reduction in CO₂ emissions and a 10–20% increase in combustion efficiency. Despite these encouraging results, these technologies remain in the experimental stage and are generally expensive. This analysis highlights the importance of further research to optimize engine designs and fuel mixtures to maximize efficiency and minimize emissions. Notably, hydrogen-enriched biofuels have shown combined reductions in NO_x and PM of over 40% in certain experiments, making them a promising solution for future sustainable energy needs. The study concludes by stressing the need for continuous advancements in renewable fuel technologies and emission control strategies to support long-term reductions in transportation emissions and encourage sustainable energy options for CI engines.