Impact of RME/Diesel Blends on Particle Formation, Particle Filtration and PAH Emissions
Vegetable oils blended to Diesel fuel are becoming popular. Economic, ecological and even political reasons are cited to decrease dependence on mineral oil and improve CO2 balance. The chemical composition of these bio fuels is different from mineral fuel, having less carbon and much more oxygen. Hence, internal combustion of Diesel + RME (Rapeseed Methyl Ester) blends was tested with particular focus on nanoparticle emissions, particle filtration characteristics and PAH-emissions. Fuel economy and emissions of bus engines were investigated in traffic, on a test-rig during standardized cycles, and on the chassis dynamometer. Fuel compositions were varied from standard EN 590 Diesel with <50 ppm sulfur to RME blends of 15, 30, and 50%. Also 100 % RME was tested on the test-rig. Emissions were compared with and without CRT traps. The PAH profiles of PM were determined. Particles were counted and analyzed for size, surface, and composition, using SMPS, PAS, DC and Coulometry.