The impact of hydrogen injection pressure and timing on exhaust, mechanical vibration, and noise emissions in a CI engine fueled with hydrogen-diesel.

The hydrogen-diesel dual-fuel mode is an efficient way of lowering exhaust emissions from compression-ignition engines. Along with exhaust emissions, mechanical vibration and noise emissions are also problems for these engines. In dual fuel mode, it is possible to reduce all emissions by using the appropriate injection strategy. In this study, different injection strategies were used in an engine with an ECU-controlled liquid and gas fuel system. In experiments, constant load (5 Nm), constant speed (1850 rpm), constant hydrogen energy ratio (12%), 4 different hydrogen injection pressures (1, 1.5, 2.0, and 2.5 Bar), and 5 different hydrogen injection starts (25, 35, 45, 55, and 65 °CA aTDC) were performed. In the study, exhaust, mechanical vibration, and noise emissions were recorded and analysed. When a few of the study's data were looked at, it was determined that CO 2 emissions decreased by 33.4% and PM emissions by 40.7% at 25 °CA aTDC injection start and 2.5 bar injection pressure. Under the same experimental conditions, NO emissions increased by 8.7%, mechanical vibration emissions increased by 19.9%, and noise emissions increased by 2 dBA. [Display omitted] • H 2 -diesel dual fuel use is effective in reducing CO, CO 2 and soot emissions. • In dual fuel mode, H 2 increased NO, mechanical vibration, and noise emissions. • Increasing the injection timing in dual fuel mode reduces emissions. • H 2 injection being lower than 25 °CA aTDC risks combustion safety. [ABSTRACT FROM AUTHOR]