The Effect Of Ignition Advance Angle On The Combustion And Emission Characteristics Of A Hydrogen Engine

Global fossil energy crisis and environmental pollution are increasingly serious.Because of being renewable,abundant,clean and having wide variety of sources,hydrogen is considered to be the ideal alternative fuel for conventional internal combustion engines by many scholars in ICE field.But it has problems of pre-ignition,backfire,knocking and other abnormal combustion phenomenon when hydrogen is used as fuel for internal combustion engines.So the improvement of power and fuel economy of hydrogen engine is restricted.At the same time,the application and development of hydrogen in-internal combustion engine is seriously hampered.This paper established the three-dimensional geometric model of the hydrogen engine whose prototype engine was Jia Ling JH600 with the Solid Works software.The combustion and emissions of hydrogen fuel engine were simulated with AVL-Fire.Effects of spark advance angle on cylinder combustion pressure,temperature,instantaneous heat release rate,accumulated heat release and NOx emission were analyzed under conditions of different speeds and equivalent fuel-air ratios.Also,the relationship between spark advance angle and restricting backfire was studied based on backfire mechanism of hydrogen engines and factors causing backfire.Finally,the optimum spark advance angle sunder different conditions were determined through comprehensive analysis of engine power,economy and emission characteristics.By the mean of iterative optimization about spark time,we find: the corresponding optimum spark advance increases as the speed increases.The optimum ignition timing angles of 1000r/min,4500r/min and 6000r/min are 7.5°CA,12.5°CA and 15°CA before Top Dead Center respectively when the equivalence ratio is 0.5.When the equivalence ratio is0.67,the corresponding angles are 5°CA、10°CA and 12.5°CA before TDC.Under theseconditions,the ignition delay period is shorter,the combustion content is better,the indication work is the maximum,the dynamic and economic indicators are better,the exhaust emission is less,which is conducive to the suppression of engine temper.In summary,it has a positive effect on inhibition of backfire of hydrogen engine to appropriately postpone the ignition timing under condition of keeping the engine power.