Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen

This research study aims to investigate the causes of the particles emitted by a spark ignition engine fueled with hydrogen. The experiments were carried out on a single cylinder 250 cm3 direct injection spark ignition engine. Two operating conditions at 2000 rpm both full and low load, representative of typical urban conditions, were investigated. A physical characterization of the particles, size and number, was performed through an Engine Exhaust Particle Sizer coupled to a single diluter. Chemical characterization was carried out on the condensed exhaust. The simultaneous analysis of the physical properties and their chemical characterization allows to point out not only the role of the oil on the particle emissions but also to give an important information on its state/composition, if it was unburned and oxidized. Particles were detected with conventional spectrometer at low load while at high load the noise signal ratio is too high to distinguish the presence of particles. More detailed chemical techniques highlighted the presence of PAH, alkyl-PAHs, oxy-PAHs and unburned hydrocarbon in the exhaust due to the mineral oil.