This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Fuel Dosing on a Diesel Oxidation Catalyst for After-treatment System Heating on a Heavy Duty Engine Powered by Polyoxymethylene Dimethyl Ethers
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
Renewable energies support efforts for restricting climate change. As power supply by solar and wind energy are subject to temporal and local fluctuations, electricity based fuels (e-fuels) offer a bridge technology for storage and distribution of carbon neutral energies. For air pollution control, the production of tailored fuels with raw pollutant emissions on a low level is meaningful. Polyoxymethylene dimethyl ethers (OME) offer the property of sustainability on the one hand, because the reactants of production are hydrogen and carbon dioxide, and air pollution control on the other hand in consequence of soot-free combustion. Therefore, high Exhaust Gas Recirculation (EGR) rates are a promising measure for nitric oxides (NOx) reduction without increasing particle emissions because of the resolved soot-NOx trade-off. However, EGR rates in direction of stoichiometric combustion in OME operation reveals other trade-offs like methane emission. Therefore, a combination of EGR and exhaust aftertreatment with selective catalytic reduction (SCR) is considered. Because the light-off temperature of SCR system limits urea dosing, heating measurements are needed. Beside electrical heating, fuel injection on the diesel oxidation catalyst (DOC) for exothermic reaction is an effective method. This is restricted by slip of unburned hydrocarbons (HC) in fossil diesel operation. Investigations on a heavy duty engine showed a reciprocal proportionality in OME operation between injection quantity and HC slip over the DOC. This behavior enables potentials for further NOx reduction in tailpipe emissions of internal combustion engines because of the possibility of earlier urea dosing in SCR systems beside lower raw emission levels caused by high EGR rates.