Low-Temperature Combustion Aftertreatment Strategy and Particle Emission Correlation with Different Dual-Fuel Ratios

An experimental test bed study was conducted in a 3.8-liter diesel common rail engine with a gasoline port injection to evaluate the aftertreatment strategy in low- and high-reactive fuel. The selection of diesel oxidation catalyst (DOC) and precious group metal (PGM) content is critical for low-temperature combustion (LTC) (dual fuel) to control hydrocarbon (HC) and carbon monoxide (CO) emissions. Three DOCs with different PGM contents were tested along with different dual-fuel compositions to understand their effectiveness and particle mass composition. The chemical composition of exhaust particles from the engine out and DOC out are compared. An increase in low-reactive fuel (D15G85) and an increase in PGM content highlights a significant reduction in particle mass (PM) from 31 mg/kWhr to 2 mg/kWhr. The major reduction in particle size distribution observed with high PGM loading is 40 nm with a dual-fuel configuration of D15G85 as the best approach to meet emission standards. Additionally, a detailed study was made to investigate the characteristics of PM and particle size distribution in the engine and aftertreatment emissions. The particle number (PN) and their correlation for engine out, DOC out, and diesel particulate filter (DPF) out emission are demonstrated with different dual-fuel combinations of D50G50, D25G75, and D15G85 compared with diesel fuel. To comprehend the characteristic of PN and PM correlation, dual fuel is tested in different ratios. A linear correlation of PM and PN emissions is observed between engine out and DOC out as particulate diameter of the particle size with the total number concentration of particles in engine out and DOC out. The nonlinear trend is observed for DPF out due to small particle size (around 5 nm) with different dual-fuel ratios. PM filter paper analyses were performed to understand chemical composition with different DOCs and dual-fuel ratios.