Particle Emissions and Size Distribution across the DPF from a Modern Diesel Engine Using Pure and Blended GTL Fuels

A Gas to liquid (GTL) fuel was investigated for its combustion and emission performance in an IVECO EURO5 DI diesel engine with a DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particle Filter) installed. The composition of the GTL fuel was analyzed by GC-MS (gas chromatography-mass spectrometry) and showed the carbon distribution of 8-20. Selected physical properties such as density and distillation were measured. The GTL fuel was blended with standard fossil diesel fuel by ratios of diesel/GTL: 100/0, 70/30, 50/50, 30/70 and 0/100. The engine was equipped with a pressure transducer and crank angle encoder in one of its cylinders. The properties of ignition delay and maximum in-cylinder pressure were studied as a function of fraction of the GTL fuel. Particle emissions were measured using DMS500 particle size instrument at both upstream (engine out) and downstream of the DPF (DPF out) for particle number concentrations and size distribution from 5 nm to 1000 nm. The results show that total particle number concentrations were significantly reduced with the increase of GTL fuel fractions. The particle number emissions reduction was captured both from nucleation and agglomeration mode particles. The significant reduction in particle emissions were due to the chemical composition of the GTL fuel, dominantly alkanes without aromatics, which leads to more complete combustion. The ignition delays were reduced with the increasing of blending ratio of the GTL and GTL blends also showed shorter combustion duration when compared to diesel fuel at low engine power test conditions.