Emissions and Fuel Consumption Potential of a Mild-Hybrid-Diesel-Powertrain with a Pre-Turbine Exhaust Aftertreatment

摘要

The potential to achieve a simultaneous reduction in both NOx and CO2 emissions viafitting of a pre-turbine exhaust aftertreatment system (PT-EATS) in combination with amild hybrid concept was investigated via simulation. A vehicle demonstrator was setup in parallel after a detailed hardware concept assessment which contained an electricassisted turbocharger. Furthermore the operating strategies for recuperation andturbocharger control were determined. The target system performance was definedwith limit value of 35 mg/km for NOx together with a CF of 1 to be achieved over twoWLTC-low cycles. Additionally, representative real driving cycles were investigated viasimulating many driving profiles, including short & long driving distances, low & highload operation, stop & go sections as well as urban driving. The optimized pre-turbineEATS layout achieves the target emissions in all driving cycles, except the high-speedhighways cycle. The fuel consumption penalties for engine heating for the pre-turbineEATS are in the range of 2 to 4 %. Moreover the total fuel consumption in comparisonto a standard Diesel powertrain reduced by 13 to 26 % in urban driving cycles; thisshows the large potential of the pre-turbine EATS concept with hybridization.