Analysis of the Emission Conversion Performance of Gasoline Particulate Filters Over Lifetime 2019-24-0156
Gasoline particulate filters (GPF) recently entered the market, and are already regarded a state-of-the-art solution for gasoline exhaust aftertreatment systems to enable EU6d-TEMP fulfilment and beyond. Due to their rapid market introduction, extensive field experience with GPFs is not yet available. Especially for four-way catalytic converters, the prognosis of the emission conversion performance over lifetime poses an ambitious challenge, which significantly influences future catalyst diagnosis calibrations.
In the first part of the paper, experimental GPF ash loading results are presented. Since most of the ash accumulated in the filter results from the combustion of lubricating oil additives, a burner test bench with a purpose-designed oil injection system was chosen for the investigations. The analysis of the backpressure results show that, contrary to high soot loadings, the ash load has a relatively low impact on engine performance and fuel consumption. Regarding the filtration efficiency over time, there is discrepancy between the results obtained during a “COP” (conformity of production) test and the measured values after a run-in mileage of 3,000 km that is required for the real driving emissions (RDE) tests. Due to the consecutive change in soot loading speed, the filtration efficiency has to be considered in the soot model calibration.
The paper’s second part presents the oxygen storage capacity (OSC) development of the three-way coating throughout the aging. The comparison to an ash-free thermal aging of a similar GPF illustrates the ash impact on the OSC and results in the discussion of possible simulation software solutions. Vehicle emission test results according to the Worldwide Harmonized Light-Duty Vehicles Test Procedure (WLTP) provide evidence of the extent to which the gaseous emission conversion efficiency is reduced over time. The paper concludes with an evaluation of the consequences for the catalyst diagnosis routines in series vehicle calibrations.
Stefan Sterlepper, Johannes Claßen, Stefan Pischinger, Christof Schernus, Michael Görgen, Jim Cox, Martin Nijs, Johannes Scharf, Dominik Rose, Thorsten Boger
RWTH Aachen University, FEV Europe GmbH, Corning GmbH
14th International Conference on Engines & Vehicles