Use of a Multi-Zone Combustion Model to Interpret the Effect of Injector Nozzle Hole Geometry on HD DI Diesel Engine Performance and Pollutant Emissions
A major challenge in the development of future heavy-duty diesel engines is the reduction of NOx and particulate emissions with minimum penalties in fuel consumption. The further decrease of emission limits (i.e., EPA 2007-2010, Euro 5 and Japan 05) requires new, advanced approaches. The injection system of DI diesel engines has an important role regarding the fulfillment of demands for low pollutant emissions and high engine efficiency. One of the injection system parameters affecting fuel spray characteristics, fuel-air mixing and consequently, combustion and pollutant formation is the geometry of the nozzle hole. A detailed experimental investigation was conducted at UPV-CMT using three different nozzle hole types: a standard, a convergent and a divergent one to discern the effect of nozzle hole conical shape on engine performance and emissions.