Hydrogen-diesel co-combustion characteristics, vibro-acoustics and unregulated emissions in EGR assisted dual fuel engine

Abstract

This work investigates the co-combustion characteristics of the hydrogen-diesel dual fuel with exhaust gas recirculation (EGR). The experiments were performed on a retrofitted duel fuel compression ignition engine for the entire engine load spectra, while the maximum hydrogen energy share in the study was 30%. Further, EGR was varied up to 10% to examine its effect on the hydrogen-diesel co-combustion and other relevant characteristics. It was found that although, hydrogen exhibit contrasting effects on the combustion at low and high loads, EGR continually degraded the peak combustion pressure. However, interestingly, the combustion’s variability improved on addition of EGR at higher loads, despite EGR’s detrimental effect on variability at lower loads. In addition, combustion noise and engine vibration were also studied with the aim to understand the effect of fuels and their combustion stability on such parameters. The relatively lower participation of hydrogen tends to reduce the vibrations, however, EGR leads to higher vibrations in the engine. The combustion noise however reduced with addition of hydrogen and EGR at lower loads. Further, the cumulative effect of EGR- hydrogen on the much unattended but harmful unregulated emissions was also investigated, and a synergy between the hydrogen addition and EGR was observed in this study. The present study showcases the key concerns as well as advantages in the EGR assisted hydrogen diesel combustion.