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This study shows the newest results of a near-series pre-turbo-catalyst (PTC) system reaching lowest emissions for electrified diesel passenger cars to address future emission legislation. The PTC system is developed using a state-of-the-art tool chain containing 1D & 3D simulation approaches and testing near-series exhaust gas aftertreatment systems under real-driving boundary conditions. The innovative concept of a selective catalytic reduction (SCR) PTC and a PTC bypass path solve the challenge of a thermal handshake between PTC and underfloor SCR System as well as the challenge of a particular filter regeneration. The development of adaptive PTC bypass path operation strategies based on exhaust gas and catalyst conditions enables lowest NOx and NH3. Using this concept, zero-impact NOx emissions, that don’t impact cities air quality, can be reached in a wide range of operating scenarios while sustaining full drivability and highest efficiency.

China 6 emission legislation was finalized in 2018 and the full implementation nationwide is postponed to 2021 due to COVID-19. It is foreseen that the post China 6 legislation will have more stringent primary and secondary emission requirements including further reduction of nitrous oxide (N2O) emissions and likely to include limits on ammonia (NH3) emissions. This study investigated the secondary emissions (i.e. N2O and NH3) of a variety of China 6 production gasoline vehicles operating under the worldwide harmonized light vehicles test cycle (WLTC) and random test standardized aggressive (RTS 95) cycle. It was found that N2O emissions were less than 5 mg/km on all these vehicles, far below the current China 6 limit (20 mg/km), however NH3 emissions varied from 2 to 48 mg/km among the production vehicles. The mechanisms of N2O and NH3 formation and their correlation with primary emissions were also investigated.

In order to study the influence of lubricant ash on the performance of the CN6 after-treatment system, especially the catalyst characteristics of Coated Gasoline Particulate Filter (CGPF), the system was rapidly aged on the engine bench by blending combustion method, and the ash content of 60g represented the endurance of 200kkm CGPF. The effects of CGPF with different endurance mileage on particulate matter emission, gas light-off temperature and engine performance of a Gasoline Direct Injection (GDI) vehicle were studied on the engine bench, chassis dynamometer and real-road tests. Finally, the ash distribution was analyzed by computed tomography (CT). The results showed that the vehicle equipped with CGPF could meet the requirements of CN6 particulate and gas emission limits under both worldwide harmonized light vehicles test cycle (WLTC) and real driving emission (RDE) tests.

It is estimated that operating continuously on a B20 fuel containing the current allowable ASTM specification limits for metal impurities in biodiesel could result in a doubling of ash exposure relative to lube-oil-derived ash. The purpose of this study was to determine if a fuel containing metals at the ASTM limits could cause adverse impacts on the performance and durability of diesel emission control systems. An accelerated durability test method was developed to determine the potential impact of these biodiesel impurities. The test program included engine testing with multiple DPF substrate types as well as DOC and SCR catalysts. The results showed no significant degradation in the thermo-mechanical properties of cordierite, aluminum titanate, or silicon carbide DPFs after exposure to 150,000 mile equivalent biodiesel ash and thermal aging. However, exposure of a cordierite DPF to 435,000 mile equivalent aging resulted in a 69% decrease in the thermal shock resistance parameter.

New fuel economy standards intensify the power train development for more fuel efficient vehicles worldwide. Different approaches are utilized to improve the fuel efficiency of gasoline engines. Of all concepts, including downsizing plus turbocharging, stratified operation of spray-guided gasoline direct injection (GDI) engines show the greatest fuel savings benefit. A significant challenge for stratified GDI aftertreatment systems is to develop both catalysts and systems that can reduce the high amount and cost of precious metals currently needed to meet performance standards under low exhaust temperature operating conditions. Furthermore, tighter emission standards will exceedingly require high conversion rates for HC, CO and NOx. In this paper the most recently developed catalyst and systems for lean GDI aftertreatment will be compared with serial production EURO 5 systems against future legislated targets.

The reduction of diesel emissions will remain a major challenge in the near future. Based on the expected emissions legislation for Europe and NAFTA, respectively, two main routes to approach this challenge are possible. Especially for the NAFTA market the use of a NOx emission control system is highly probable due to the established low limit for NOx emissions. From today's point of view only two systems - the NOx storage catalyst and the SCR catalyst system - have the potential to reach these limits. In Europe the expected Euro5 NOx limit can most likely be reached by engine measures only. Nevertheless both markets have the common understanding that besides the further improvement by internal engine measures the diesel oxidation catalyst (DOC) as well as the catalysed diesel particulate (DPF) filter will play an essential role in diesel emissions reduction.

Modern Diesel Engines equipped with Common-Rail Direct Injection and EGR are characterized by an increasingly high combustion efficiency. Consequently the exhaust gas temperature, especially during a cold start, is significantly reduced compared to typical values measured in previous engine generations. This leads to a potential problem with CO emission limit compliance. The present paper deals with an experimental investigation of turbulent-flow metal substrates, carried out on a vehicle roller bench using a production 1.3 Liter diesel engine equipped passenger car. The tested metal supported catalysts proved to yield extremely high conversion rates both during cold start and in warm operation phase. The improved mass transfer efficiency of the advanced metal substrates is related on one hand to the optimized coating technology and, on the other hand, to the enhanced flow performance in the single converter channels which is caused by structured metal foils.

Future stringent emission levels for NOx and PM will lead to the introduction of innovative combustion processes for diesel engines, such as premixed combustion, with the results to enhance the engine out emission of HC and CO. Therefore very efficient oxidation catalyst will be needed to face this possible issue. This paper deals with the optimization of a EU IV exhaust system by means of innovative metal supported catalyst, as for example the Pre Turbo Catalyst and the Hybrid Catalyst in combination with dedicated catalyst coatings. Moreover a base study over the use of PM-Filter Catalyst has been made, to show the efficiency of such a device with EU IV engine calibration. The second part of the paper deals with the turbulent like structured foils substrates to have an even more efficient diesel oxidation catalyst with very high volumetric efficiency.