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In order to meet the challenging CO2 targets beyond 2020 despite keeping high performance engines, Gasoline Direct Injection (GDI) technology usually combined with charged aspiration is expanding in the automotive industry. While providing more efficient powertrains to reduce fuel consumption one side effect of GDI is the increased particle formation during the combustion process. For the first time for GDI from September 2014 there is a Particle Number (PN) limit in EU of 6x10 sup 12 #/km, which will be further reduced by one order of magnitude to 6x10 sup 11 #/km effective from September 2017 to be the same level as applied to Diesel engines. In addition to the PN limit of the certification cycle NEDC further certification of Real Driving Emissions (RDE) including portable PN measurements are under discussion by the European Commission. RDE test procedure requires stable and low emissions in a wide range of engine operations and durable over a distance of 160 000 km.

Low fuel consumption and improved power output are the main market drivers in the automotive industry. For these challenges, Gasoline Direct Injection (GDI) technology provides higher thermal efficiency than Multi Point Injection (MPI) engines and this technology is expanding as a solution to reduce CO₂ and improve driveability. In Europe under the Euro 5 regulation, engine downsizing becomes a major solution to reduce CO₂ of gasoline engines. For this concept GDI is essential together with turbocharging technology. However GDI technology increases particulate matter (PM) emissions compared to MPI engines. As the introduction of a Particle Number (PN) regulation for Euro 6 GDI vehicles has been decided, technologies to reduce GDI PN emissions start to become necessary. For this requirement, a gasoline particulate filter (GPF) is an effective solution.

Heavy Duty Vehicle (HDV) Diesel emission regulations are set to be tightened in the future. The introduction of PN PEMS testing for Euro VI-e, and the expected tightening of PM/NOx targets set to be introduced by CARB in the US beyond 2024 are expected to create challenging tailpipe PN conditions for OEMs. Additionally, warranty and the useful life period will be extended from current levels. Improved fuel efficiency (reduction of CO2) also remains an important performance criteria. Furthermore, future non-road diesel emission regulations may follow tighten HDV diesel emission regulations contents, and non-road cycles evaluation needs to be considered as well for future. In response to the above tightened regulation, for Diesel Particulate Filter (DPF) technologies will require higher PN filtration performance, lower pressure drop, higher ash capacity and better pressure drop hysteresis for improved soot detectability.

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.

A Particle Number (PN) limit for Gasoline Direct Injection (GDI) vehicles was introduced in Europe from September 2014 (Euro 6b). In addition, further certification to Real Driving Emissions (RDE) is planned [1] [2], which requires low and stable emissions in a wide range of engine operation, which must be durable for at least 160,000 km. To achieve such stringent targets, a ceramic wall-flow Gasoline Particulate Filter (GPF) is one potential emission control device. This paper focuses on a catalyzed GPF, combining particle trapping and catalytic conversion into a single device. The main parameters to be considered when introducing this technology are filtration efficiency, pressure drop and catalytic conversion. This paper portrays a detailed study starting from the choice of material recipe, design optimization, engine bench evaluation, and final validation inside a standard vehicle from the market during an extensive field test up to 160,000 km on public roads.

The LDV gasoline emission regulation is set to be tightened for Euro7. In particular, the particulate number (PN) requirement has been significantly tightened requiring a GPF with extra - high filtration efficiency to meet the target requirement. In order to meet the stricter PN requirements, GPF substrate material improvement is necessary. However, conventional GPF material improvement for high filtration efficiency will increase the filter backpressure significantly. The relationship between pressure drop and CO2 emission is difficult to quantify but high pressure drop can potentially increase the CO2 emission. Therefore, Membrane Technology (MT) is the key to break through the trade-off between filtration performance and pressure drop. MT is thin and dense layer of small grains applied on the GPF surface. MT application can increase particulate filtration efficiency significantly with minimal pressure drop increase.

Diesel Particulate Filters (DPF) are becoming mandatory for many Heavy Duty Vehicle (HDV) and Non Road Mobile Machinery (NRMM) applications as the requirement for particulate filtration performance has increased over this past decade. In a previous study, a new generation of cordierite DPF was developed to meet the latest major emission regulations; PN-PEMS requirement for EuroVI StepE, while maintaining a lower pressure drop and high ash capacity. Despite the improvements made in the latest generation DPF material, the introduction of tighter particulate regulations demands further improvement in DPF technology. More specifically, PN emission limits for Euro7 under wide operation conditions in conjunction with PN down to 10nm, as described in the proposal from Consortium for Ultra Low Vehicle Emission (CLOVE), requires further improvement in PN filtration performance. Pressure drop, which may negatively influence the CO2 emissions, remains a key performance criteria.