Comparative Study on Effect of Hydrogen and Hydrogen Blended Compressed Natural Gas on Compression Ignition Engine Operated under Homogeneous Charge Compression Ignition and Reactivity Controlled Compression Ignition Mode of Combustion

In the present work, an attempt was made to study and compare the effect of hydrogen (H₂) and hydrogen blended compressed natural gas (HCNG) as primary fuels along with diesel and Simarouba biodiesel as secondary fuels in compression ignition (CI) engine operated under homogeneous charge compression ignition (HCCI) and reactivity controlled compression (RCCI) mode of combustion. Compressed natural gas (CNG) can blended with H₂ at the proportion of 20% of H₂. Experiments have been conducted on single cylinder CI engine running at 1500 rpm at 75% load for RCCI mode of operation and 50% load for HCCI mode of operation by varying gaseous energy share. The results show that RCCI engine operated with H₂ and HCNG exhibits higher brake thermal efficiency (BTE) as compared with HCCI engine operated with same gaseous fuels. At 40% of gaseous fuels energy share (GFES) results in higher brake thermal efficiency along with reduced emissions. Nitric oxide (NOx) and smoke emissions were reduced significantly for RCCI mode as compared with HCCI combustion mode. Beyond 40% gaseous fuels energy share there is penalty of lower thermal efficiency and higher emissions. Among primary fuels tested H₂ gives better results as compared with HCNG for both HCCI and RCCI mode of combustion.