Correlation Between Hydraulic Nozzle Flow Rate of Diesel Injectors and HC Emissions.

The correlation between diesel injector hydraulic nozzle flow rate and HC emissions under light load conditions was investigated using two injection nozzles with different hole diameters. Experimental results showed that (1) a reduced hydraulic nozzle flow rate (by reducing the nozzle hole diameter) is accompanied by stronger spray tip penetration when the fuel injection quantity is limited to the level of pilot injection, (2) the strong penetration accelerates fuel spray diffusion, creating an over-lean area in the fuel-air mixture, which causes an increase in HC emissions under light load conditions. [ABSTRACT FROM AUTHOR]