A research on the backfire in a port injection hydrogen engine

Due to the low ignition energy of hydrogen-air mixture, backfire and other abnormal combustion phenomena often happen in hydrogen engine, affecting its performances. For investigating the situation of backfire in port injection hydrogen engines at different loading conditions, an experimental study is conducted on a 2.0 L four-cylinder hydrogen engine. The results show that when hydrogen engine works at low load condition, the combustion velocity of hydrogen-air mixture is rather low and a large amount of unburned hydrogen remains, leading to the occurrence of backfire; while at high load condition, the high temperature residual exhaust gas or hot spots in cylinder ignite the hydrogen-air mixture and cause backfire.