Influence of Electronically Controlled Hot and Cold External ReBreathing System in DI-CI Diesel Engine for Reducing NO_x Emission

The World Health Organization published a report, saying that diesel fumes do cause cancer; this is due to higher levels of nitrogen oxides and particulate matter diffused with air. In an investigation point of view, most of the researcher’s accepting that external rebreathing system is the successful way of reducing the NO_x in the diesel engine. This paper focused on comparing the hot and cold external rebreathing system used to reduce NO_x emission. A one-cylinder four-stroke H₂O-cooled DI-CI engine coupled with an eddy current dynamometer equipped with electronics-based Ethernet-controlled digitalized hot and cold external rebreathing system was used to analyze the percentage of EGR admitted to the engine. The present experimental investigation is carried out compared to the baseline data with 10% hot and cold rebreathing system. The experimental result shows the brake thermal efficiency of hot EGR 1% increases compared to cold EGR and 1.5% increased without EGR. Emissions like HC, CO, CO₂, and NO_x are reduced 14.21%, 12.5%, 6.12%, and 48%, respectively, and smoke level increased 7.26% compared the baseline data of the diesel engine without rebreathing system. The related information of the present work with other researchers’ works is detailed in the literature. Overall, the experimental results proved that combust gases will be advantageous in promoting quick auto-ignition of mixed air/fuel, and cooled burned gases would be accepted to obtain already mixed air/fuel mixture.