Estimation of assorted injection schedules on hydrogen-diesel dual fuel and reactivity controlled compression ignition modes in a medium duty automotive engine

Intention of this research is to comprehend the impact of injection parameters on dual fuel and RCCI combustion strategies using hydrogen as the primary fuel and diesel as the ignition source. The study also aims to achieve a smooth transition between these two modes. In this experimental analysis, the quantity of hydrogen and diesel fuel has been equally divided. Hydrogen fuel has been inducted through intake manifold whereas diesel has been injected directly into the cylinder. The quantity of diesel injected is split between two pulses and studied for combustion, performance and emission attributes by altering the timing of first pulse injection whilst maintaining a constant second pulse injection timing. The results show that splitting the diesel fuel quantity equally between two pulses produces the optimum outputs for the study. The research proposes a first pulse of 30 degrees bTDC for hydrogen-diesel dual fuel (HDDF) mode whereas, for hydrogen-diesel RCCI (HDRCCI) mode of combustion, the best first pulse injection timing has been selected as 60 degrees bTDC. The experiment accomplished a smooth transition between HDDF mode and HDRCCI mode by gradually advancing the injection timing without disturbing the performance parameters significantly while accomplishing noteworthy reduction in NOx and negligible variations in other emission parameters.