Simulation of Scavenging Process, Internal Mixture Preparation, and Combustion of a Gasoline Direct Injection Two-Cylinder Two-Stroke Engine

The continuous improvement of the numerical methods together with the increase of computer power allows the simulation of more and more complex technical problems even for increasing calculation domains. In order to get effective and significant results for the two-stroke two-cylinder engine, the simulation of the complete geometry with both cylinders and the complete exhaust port is required. However, the simulation requires several revolutions until the gas dynamic inside the exhaust port achieves a steady state. Hence, the simulation of a two-cylinder two-stroke engine consumes a lot of calculation time; nevertheless it is still acceptable in the development process of a new engine.

This paper covers the discussion of the simulation of a two-stroke two-cylinder high-performance engine using the commercial CFD Code Fluent 6.3.26. The used settings for the simulation, like the turbulence model, injection settings, combustion model and reduced reaction mechanism are presented. The results of the scavenging process, internal mixture preparation and combustion are also discussed in detail. Test bench results of the fired engine were used for the validation of the simulation. The main focus lies on the accuracy of the results using the standard models from the conventional CFD code Fluent and their computational efficiency. Finally, the use of the simulation for development tasks, e.g. the improvement of a two-cylinder two-stroke engine, will be demonstrated.