Several studies have shown that the INHN affects the exhaust emissions of diesel engines. Montgomery et al. [10] investigated the effects of number of size and hole on the emissions of a DI heavy duty diesel engine. The injector nozzle hole size and number combinations used in the experiments included 225 8 (225 mm diameter holes with 8 holes), 260 6, 260 8, and 300 6. Results showed that the best emissions and second best BSFC were obtained with the nozzle with the maximum INHN.