Experimental Study on the Effect of Concentrated Turbulence around the Spark Plug Zone in a Swirling Flow on a Hydrogen SI Engine Performance and Combustion Parameters

This study investigates the effect of concentrated turbulence in the spark plug zone on engine performance and combustion parameters in a hydrogen engine. The swirling flow in the cylinder was directed to the spark plug zone by a turbulator-shaped piston head during the compression stroke. The engine was operated under lean mixture and wide-open throttle (WOT) conditions at different engine speeds. Depending on the engine speed, it was found that the concentrated turbulence around the spark plug zone enhances the engine performance between 4.3 and 7.8%. The combustion duration and the cyclic variation in the engine were also reduced with the concentrated turbulence in the spark plug zone. The reduction in combustion duration was higher in the first combustion period [0-10% mass fraction burned (mfb)] than that in the other two combustion periods (10-90% and 90-100mfb). While the indicated mean effective pressure (imep) increased, the coefficient of variations of imep was markedly decreased thanks to the concentrated turbulence around the spark plug zone.