INVESTIGATION OF AN SI-CAI ENGINE FUELLED WITH METHANE-HYDROGEN MIXTURES FOR DIFFERENT EXHAUST VALVE LIFTS

Özet

In this study, a spark-assisted controlled auto-ignition (SI-CAI) engine with different Methane-Hydrogen blends was numerically and experimentally investigated under different excess air ratio and valve lift value conditions. Experimental results were used to validate the numerical study. GT-Power simulation tool was used for the numerical studies. The valve lifts were created ranging from 3.0 to 5.0 mm with 0.5 increments. The excess air ratio () values were considered as 1.0, 1.1, 1.2, 1.3 and 1.4. Besides, Methane-Hydrogen blends were constituted as 100% Methane (100M), 90% Methane-10% Hydrogen (90M10H), 80% Methane-20% Hydrogen (80M20H) and 70% Methane-30% Hydrogen (70M30H) by volume. Results revealed that the peak pressure values increase when the valve lift increases. The pressure and temperature values tend to reduce with the increasing of  values. Increasing the volume fraction of Hydrogen in Methane–Hydrogen blend contributes to pressure development earlier. As a conclusion increasing of the volume fraction of Hydrogen in the Methane-Hydrogen blend causes a reduction in the indicated thermal efficiency and mean effective pressure, and a lower specific fuel consumption.