Cycle variations in a hydrogen internal combustion engine

摘要

The cycle variation characteristics of a port fuel injection hydrogen internal combustion engine (PFI-HICE) have been extensively investigated. The covariance of indicated mean effective pressure (COV_(imep)) is the best parameter for evaluating the cycle variations in the PFI-HICE. COV_(imep) decreases as fuel-air ratio increases from 1000 to 5500 rpm, and engine speed minimally affects COV_(imep). The effect of ignition advance angle on COV_(imep) is determined by fuel-air ratio. The ignition advance angles that correspond to the minimum COV_(imep) of the PFI-HICE decrease as fuel-air ratio increases. The effect of ignition advance angle on COV_(imep) diminishes as fuel-air ratio increases. The COV_(imep) of the PFI-HICE rapidly decreases as throttle increases when the throttle is less than 20%. Injection timing only slightly affects COV_(imep) under high-speed conditions, and COV_(imep) increases when hydrogen is injected in intake periods under low-speed conditions. These results indicate that studying COV_(imep) improves the stability of PFI-HICEs.