The effects of the combustion chamber geometry and a double-row nozzle on the diesel engine emissions:

This paper presents how injector nozzle distributions and the combustion chamber geometry affect the emission characteristics of diesel engines. The number of nozzle holes was increased from seven to 12 by a using double-row nozzle distribution to enhance the air–fuel mixing and the spatial distribution of the spray while avoiding spray overlap. The combustion chamber geometry was modified to have a wide shallow two-step bowl, which ensured adequate spray penetration with the double-row nozzle, to observe the influence of the spray–piston interaction on the combustion and emissions. Three hardware combinations (a seven-hole single-row nozzle with a conventional piston, a 12-hole double-row nozzle with a conventional piston, and a two-step piston) were tested in a single-cylinder direct-injection diesel engine under three boost and exhaust gas recirculation conditions. The injection timing was adjusted to result in a similar power by maintaining 50% of the total fuel mass fraction burned points for each ha...