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This paper introduces a research project on a spark ignition engine used in non-road applications. The aim is to illustrate the present situation as basis for comparison and to identify possible improvement potential in terms of performance, efficiency or exhaust and noise emissions. The study is carried out in two steps. First a standard walk-behind lawn mower is equipped with measuring instrumentation for recording the cutting forces and the engine variables during real world operation. The tests are carried out on three different lawn types and two different blade types are investigated. Consequently, in a second step the engine is analysed on the engine test bench in stationary and transient operating mode. A complete engine mapping is done regarding all relevant variables. Additionally to the outdoor tests, fuel consumption and engine out emissions are measured on the engine dynamometer. The recorded data enables a detailed analysis of the engine behaviour.

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.