Numerical study of ducted fuel injection strategy for soot emissions reduction in a heavy-duty diesel engine

Abstract

This study investigates the method of ducted fuel injection (DFI) technology to improve fuel–air mixing and reduce soot emissions in heavy-duty diesel engines, addressing critical challenges in sustainable combustion technology. While optical engine experiments have demonstrated DFI’s potential for emissions reduction, challenges arise when translating these results to actual diesel engines due to differences in design and operational conditions. Unlike previous optical engine experiments, this work evaluates DFI under real engine operating conditions through comprehensive numerical simulations. For the first time, the mechanisms of soot emission formation and control with DFI in a practical engine are elucidated. Results show that injection timing significantly affects engine performance, with the optimal timing for the original engine at −12° CA ATDC, achieving an indicated mean effective pressure (IMEP) of 16.55 bar and minimizing soot emissions (1.78 g/kWh). The engine with a directly installed duct (without optimization) improves early-stage combustion but extends later-stage combustion, reducing IMEP to 14.90 bar and increasing soot and CO emissions. By optimizing duct parameters—such as jet direction, number of ducts, and offset angle—we improve fuel–air distribution and in-cylinder airflow dynamics. Our findings indicate that this optimization not only slightly increases the IMEP of 16.56 bar but also significantly reduces soot emissions by 8.99 % and hydrocarbons (HC) emissions by 96.05 % compared to the original engine. These findings highlight the potential of DFI technology for effective emission control and sustainable engine performance, advancing its practical application in heavy-duty diesel engines.