The Effects of Piston Bowl Shape in Emission Formation for Direct Injection Heavy Duty Diesel Engine

The piston bowl design is one of the most important factors that affect the air-fuel mixing and the subsequent combustion and pollutant formation processes in a direct-injection diesel engine. The bowl geometry and dimensions are known to have considerable effect on the in-cylinder mixing and combustion process. In order to make a deep understanding of the effect of geometry, three piston bowls are subjected to computational fluid dynamics engine modeling. A CFD code is used to model the in-cylinder flows and combustion process. This code is than validated on a heavy duty diesel engine with a common-rail fuel injection system. The engine s performance, in-cylinder flow and combustion, and emission characteristics were analyzed at maximum power and maximum torque conditions. The objective of this work is to determine the piston bowl among a few applicable piston shapes to improve combustion quality, power and emission.

Keywords:

diesel spray , diesel combustion , bowl shape , NOx emission , soot emission.