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Measuring axial exhaust species concentration distributions within a wall-flow aftertreatment device provides unique and significant insights regarding the performance of complex devices like the SCR-on-filter. In this particular study, a less complex aftertreatment configuration which includes a DOC followed by two uncoated partial flow filters (PFF) was used to demonstrate the potential and challenges. The PFF design in this study was a particulate filter with alternating open and plugged channels. A SpaciMS [1] instrument was used to measure the axial NO2 profiles within adjacent open and plugged channels of each filter element during an extended passive regeneration event using a full-scale engine and catalyst system. By estimating the mass flow through the open and plugged channels, the axial soot load profile history could be assessed.

The conventional evaluation of automotive catalysts has been carried out based on end-pipe measurement whereby the gas at the tailpipe of an automobile or the outlet of the bench reactor is monitored by using various analytical techniques such as Fourier-transform infrared spectroscopy (FTIR), mass spectrometry (MS), and gas chromatography (GC). However, this approach only provides overall gas concentrations at the exit flow of a monolith catalyst. Thereby, there is a deficiency of information on intra-catalyst chemistry. To obtain deeper insights on the design of an automotive catalyst, an emission breakdown analysis is critical. In this way, a comprehensive understanding of continuous processes along the catalyst length can be achieved. Here, we introduce the High Throughput Vehicle Test (HTVT), which is an analysis technology method for simultaneous emission observations at different catalyst positions in the vehicle.

Improved Lean NOx Trap (LNT) catalysts with enhanced NH3 generation feature were developed for the small diesel engine. The next generation LNT system needs to perform good NOx conversions over the wide temperature range including below 200°C for urban driving and above 400°C for motorway of real road driving. However, the extended use of BaO, a component of LNT known to be very effective for high temperature NOx storage, results in the decrease of low temperature NOx conversion due to the degradation of NO oxidation associating with sulfur over time. The improvement of the low-temperature LNT performance is a key requirement for the real driving emission control as the best operation temperature for urea-SCR is above ~250°C. In this study, our next generation LNT with new washcoat architecture has demonstrated improved NOx removal efficiencies under the wider operation temperature window than the current production technology.