Effects of Intake Port Geometry on the Performance of an SI Engine 2011-32-0506

Flow field within the intake port determines the mass flow into the engine and in-cylinder charge motion of the spark ignition engine, which further influences power output, emissions and fuel consumption. Hence, a detailed investigation of influence of intake port geometry on the engine performance is required.

In the present project work, an existing intake port of a single cylinder, 4-stroke and air-cooled gasoline engine was experimentally and numerically investigated. This intake port is further subjected to variation in geometry towards improving the volumetric efficiency and subsequently the power output has been estimated. Initially a steady state flow analysis was carried out for various intake port designs at different valve lift positions to determine the mass flow into the engine. The best intake port design based on the steady state flow analysis results was considered for unsteady analysis to determine the peak cylinder pressure and emission characteristics of the engine.

Comparison of the CFD results with the experimental results for the baseline intake port design showed a good agreement. The CFD results predicted that the optimised design allows achieving increased mass flow rate by 20% at peak valve lift condition and increased combustion peak pressure by 10.7% at 5000 rpm.