Investigation of Injection Timing and Hydrogen Energy Share on a Direct Injection SI (DISI) Engine Fuelled with Parallel Direct Injection of Hydrogen and Ethanol

Sustainable automotive power systems require low-carbon fuels that retain the advantages of conventional internal combustion engines. The current study conducted experiments to examine the combined influence of ethanol injection timing (EIT) and hydrogen energy share (HES) in a parallel dual-direct-injection spark-ignition engine, with direct injection of ethanol and hydrogen at 120 and 10 bar, respectively. Hydrogen injection timing was set at 26 °CA ATDC, EIT varied from 80 °CA ATDC to 160 °CA ATDC, and hydrogen injection ratio (HES) varied from 0% to 20%. For the highest brake thermal efficiency (25.381%), the results indicated 15% HES and 130 °CA EIT, which were 1.94% better than neat ethanol. Under these conditions, the CA10 decreased by 10.8%, and the peak cylinder pressure and peak cylinder temperature increased by 6.36% and 2.60%, respectively. At 20% HES, CA10–90 decreased by 14.61%, peak heat-release rate increased by 11.14%, and CoVIMEP decreased by 16.35%. When 15% HES and 130 °CA EIT are used, the levels of CO, HC, and CO2 emissions were reduced by 16.05%, 16.36%, and 9.89%, respectively, despite an increase of 19.32% in the levels of NOx emissions. It can be observed that injecting ethanol using hydrogen energy shares will improve the above factors.