Destruction of diesel soot aggregates with the use of fuel-borne oxygen and the application of hydrogen assisted SCR catalyst

The sustainability of diesel-powertrain technology in the light-duty vehicles’ market is mainly dependant on the level to which the engine-out emissions, mainly particulate matter (PM) and nitrogen oxides (NOx), can be supressed. The use of new-fuel generation, fuel injection calibration and advanced aftertreatment devices is the main state-of-the-art technology to control diesel emissions. To evaluate the impact of alternative fuels and in-cylinder post-fuel injection (PFI) on PM characteristics and a non-commercial silver alumina hydrocarbon selective catalytic reduction (HC-SCR) catalyst, glycol ether-diesel blends were studied at various steady-state engine operating conditions. The results indicate that glycol ethers combustion permits a lower NOx/PM trade-off and produces more reactive PM compared to neat diesel. Introduction of PFI can adequately regulate the exhaust HC:NOx ratios to fully activate the HC-SCR when minute concentration of Hydrogen (H2) is fed to the flow. Considering the effective de-NOx mechanism shown with this application, the soot destruction throughout the catalyst was also examined to reveal synergies that can assist in the development of the next generations of aftertreatment devices. Given the needed enhancers (H2) and exhaust temperatures, HC-SCR can effectively breakdown and oxidise the soot aggregates throughout the catalyst channels despite of the limited catalyst/soot residence time.