Design of a Tumble-Orientated Intake Port Layout for a Gasoline Combustion Process Used in Power Sport Application

In this publication, an intake design study was implemented in the development of a GDI engine concept at the Institute for Internal Combustion Engines and Thermodynamics at Graz University of Technology. For a high performance three-cylinder gasoline engine, different intake port geometries were developed, designed and evaluated with CAD and 3D CFD simulation methods. An emission reduction might be achieved with the improvement of the combustion behavior, as well as an increase of performance with an optimized cylinder charging. The combustion behavior was influenced by increasing the turbulence level via an intensified charge movement. The assessment criteria comprised the cylinder charge represented by the flow coefficient and the charge movement using the tumble number. The different intake designs were investigated in terms of a naturally aspirated engine concept using external (MPFI concept) and a supercharged engine concept with an internal homogeneous fuel mixture formation (DI concept). The studies took place in three basic steps. In the first, the statistical methodology of design of experiments (DoE) was applied to evaluate different parameters; the second consisted of a comparison of different intake port variants using a steady state flow simulation. In the third step, a detailed comparison of two intake port variants using a transient flow simulation was carried out.

The primary objective was to present the best possible charge movement without losses in the cylinder charge. The requirement on the intake port layout was thus to generate “low-loss” tumble flow. Furthermore, it was attempted to use the intake port geometry for two cylinder head concepts (DI and MPFI combustion process).