Effects of injector nozzle hole number and hydraulic flow rate on combustion and emission characteristics in a heavy duty diesel engine

Abstract

This study investigated the influence of the number of injector nozzle holes and hydraulic flow rate (HFR) on combustion and emission characteristics in a 1.1L single cylinder diesel engine equipped with a direct injection system. In addition, the spray development processes were visualized at a constant volume chamber by using a high speed camera. The test injectors of the present study have number of holes from 6 to 12. In addition, effects of HFR on spray development and engine performances were investigated at fixed 8 holes. Results showed that particle emissions emitted from the engine were reduced as the number of injector nozzle holes increased. This is a result of the advantage of the mixture formation because the nozzle holes diameter is reduced and droplets of smaller size are injected as the number of nozzle holes increases. However, NOx emission, which is a trade-off relationship with particulate matter (PM), tends to increase as the number of holes increases. This is because the initial droplets are decreased and the mixture formation is advantageous. ? 2018 Solar Turbines Incorporated.