Numerical investigation of different combustion chamber on flow, combustion characteristics and exhaust emissions

Abstract

This study includes numerical analysis of diesel engine with different bowl geometry. 3D CFD analyzes of the engine with asymmetrical piston geometry were performed in Ansys Forte software. In the study, a single-cylinder, four-stroke and direct injection diesel engine was used. It has been tested where the maximum torque is obtained as the operating condition at 2000 rpm. According to the results obtained from the analyzes, the new combustion chamber system (NCCS) geometry provided a 40.3% reduction in soot emissions while NO emissions increased slightly with the 8-cavity bowl geometry created in the combustion chamber compared to the standard combustion chamber system (SCCS). Increasing air velocity and turbulent kinetic energy (TKE) values in the combustion chamber affected the evaporation levels of the fuels. As a result, the improved mixture formation caused a decrease in incomplete combustion products (CO, HC and soot). The NCCS geometry according to SCCS type, an increase of approximately 4.2% occurred in the calculated squish rates. It has been observed that the increase in the bowl surface area causes the combustion and thus the temperature to spread over a larger area on the piston.

Analysis of an innovative combustion chamber with the wall guided fuel injection in a small diesel engine

“…It is one of the most preferred models for modeling the engines as suggested by some the articles. 47,48 Adaptive Collision Mesh model was used for droplet collision. One of the biggest advantages of this model is that it eliminates the dependency on the mesh structure.…”

“…Higher turbulence intensity causes an increase in the surface area of the flame and, as a result, an increase in the combustion rate. 48,54,52 In parallel with the increase in the guided angle of the fuel, it is thought that the distribution of the fuel sprays between the cavities further increases the homogeneity tendency and the wall/fuel interaction. However, this situation is thought to affect the increase in NO emissions.…”