Potential for Particulate Reduction by Use of eFuels in MPFI Engines

Currently, emission regulations for the LVs using standard spark ignited ICEs considering only gaseous pollutants, just as CO, HC and NOx. Following the upcoming legislation for personal vehicles sector, the LVs might also include limits of PN and PM. Regarding fuel injection strategies, the MPFI which was previously excluded from particulate control will be incorporated into the new regulation 1. In terms of social harm, there will be a necessity to reduce engine particulate emissions, as they are known for being carcinogenic substances 2, 3, 4. Generally, the smaller the particulate diameter, the more critical are the damages for human health therefore, the correct determination of PN and particulate diameter is essential. Beside future challenges for reducing and controlling particulates, the reduction of fossil fuel usage is also an imminent target, being the replacement by eFuels one of the most promising alternatives. Therefore, the particulate generation behavior of eFuels and the influence of their novel fuel composition need to be researched. Hence, gas chromatography of five different eFuel blends was carried out in order to identify precisely the fuel composition and subsequentially correlate it with particulate emission behavior. Thereafter, the impacts of eFuel functional groups on PM/PN were studied using a motorcycle equipped with a two-cylinder engine by two different experiments. First, the standard homologation test cycle WMTC was selected for evaluating the total PM/PN emitted. Then, particulate size distribution at steady state condition was investigated to determine soot composition at two different operational load points of the vehicle, utilizing a scanning mobility particulate sizer (SMPS). By adopting this approach, it becomes possible to develop strategies for reducing particulate emissions by taking into account fuel composition and a comprehensive analysis of particle size distribution.