A Preliminary Study on Intake Flow to Improve In-Cylinder Air Motion

The intake flow of a diesel engine significantly affects the combustion characteristics, thus influencing the power output, fuel efficiency and the emissions. In this thesis work, simulations using computational fluid dynamics (CFD) along with steady flow experiments were conducted to study the intake flow of a Yanmar NFD-170 diesel engine. The in-cylinder air motion generated by the intake flow through the helical intake port was studied. In order to model the shape of the engine accurately, a three dimensional model of the engine intake port, cylinder head and cylinder was produced using AutoDesk Inventor. The air motion was simulated under steady flow conditions using Converge CFD software, and the simulation results were compared with the experimental results to validate the model. The results indicated that major features of the steady flow were well modeled at particular flow conditions