Experimental Investigations on Particle Number Emissions from GDI Engines

Experimental Investigations on Particle Number Emissions from GDI Engines



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Markus Bertsch | 2016 | ISBN: 3832544038 | English | 167 pages | PDF | 5 MB

This thesis discusses experimental investigations to reduce particle number emissions from gasoline engines with direct injection. Measures on a single cylinder research engine with combined usage of a particle number measurement system, a particle size distribution measurement system as well as optical diagnostics and thermodynamic analysis enable an in-depth assessment of particle formation and oxidation. Therefore, numerous optical diagnostic techniques for spray visualisation (Mie-scattering, High-Speed PIV) and soot detection (High-Speed-Imaging, Fiber optical diagnostics) are deployed.

Two injectors with different hydraulic flows but identical spray-targeting are characterised and compared by measurements in a pressurised chamber. The operation at higher engine load and low engine speed is in the focus of the experimental work at the engine test bench. Thereby, the low flow velocities in the combustion chamber, caused by the low engine speed, as well as the large amount of fuel injected are major challenges for the mixture formation process. A substantial part of the thesis thus focusses on the detailed analysis of the mixture formation process, which is consisting of fuel injection, interaction of the in-cylinder charge motion with the fuel injected and the fuel properties.