An investigation of a cause of backfire and its control due to crevice volumes in a hydrogen fueled engine

To understand the occurrence of backfire in hydrogen fueled engines using art external (inducted) fuel supply, a fundamental study was completed using a modified experimental engine. A relation was found between the crevice volume in the combustion chamber and the occurrence of backfire. The results showed that the crevice around the spark plug electrode was not a major cause of backfire, but the combustion state of the mixture in the piston top land crevice, second land, and ring groove did have a direct affect on backfire occurrence. By increasing the top land crevice volume and the amount of flow-by gas, the equivalence ratio before backfire occurred was extended.