Cycle variations in a hydrogen internal combustion engine

The cycle variation characteristics of a 2.0, L port fuel injection hydrogen internal combustion engine (PFI-HICE) have been extensively investigated. The results show that the covariance of indicated mean effective pressure C_imep is the best parameter for evaluating the cycle variations in the PFI-HICE. C_imep decreases with the increase of idle speed or fuel-air ratio. The effect of ignition advance angle on C_imep diminishes as fuel-air ratio increases. The ignition advance angles that correspond to the minimum C_imep of the PFI-HICE decrease as fuel-air ratio increases. The Cimep of the PFI-HICE rapidly decreases as throttle increases when the throttle is less than 20%. The C_imep increases when hydrogen is injected in intake periods under idle conditions. These results indicate that the study on C_imep improves the stability of PFI-HICEs.