Performance of Next Generation Gasoline Particulate Filter Materials under RDE Conditions

In order to meet the challenging CO₂ targets beyond 2020 without sacrificing performance, Gasoline Direct Injection (GDI) technology, in combination with turbo charging technology, is expanding in the automotive industry. However, while this technology does provide a significant CO₂ reduction, one side effect is increased Particle Number (PN) emission. As a result, from September 2017, GDI vehicles in Europe are required to meet the stringent PN emission limits of 6x10¹¹ #/km under the Worldwide harmonized Light vehicles Test Procedure (WLTP). In addition, it is required to meet PN emission of 9x10¹¹ #/km under Real Driving Emission (RDE) testing, which includes a Conformity Factor (CF) of 1.5 to account for current measurement inaccuracies on the road. This introduction of RDE testing in Europe and China will especially provide a unique challenge for the design of exhaust after-treatment systems due to its wide boundary conditions. Previous investigations have shown that Gasoline Particulate Filter (GPF) technology is an effective method to reduce PN emissions, with minimal impact on CO₂ emissions. Due to increasingly stringent global emission requirements as well as the implementation of RDE testing conditions, it is critical to continuously develop and improve GPF performances. In this study, GPF of various design configurations were initially evaluated under laboratory conditions, from which several candidates wereselected for further evaluation under RDE conditions. As a result, next generation GPF achieved high filtration performance while maintaining acceptable pressure drop levels.