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Technical Paper

Particle Number Emission Reduction for GDI Engines with Gasoline Particulate Filters

2017-10-08
2017-01-2378
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.
Technical Paper

Development of New High Porosity Diesel Particulate Filter for Integrated SCR Technology/Catalyst

2015-09-01
2015-01-2018
Diesel engines are widely used to reduce CO2 emission due to its higher thermal efficiency over gasoline engines. Considering long term CO2 targets, as well as tighter gas emission, especially NOx, diesel engines must become cleaner and more efficient. However, there is a tradeoff between CO2 and NOx and, naturally, engine developers choose lower CO2 because NOx can be reduced by a catalytic converter, such as a SCR catalyst. Lower CO2 engine calibration, unfortunately, leads to lower exhaust gas temperatures, which delays the activation of the catalytic converter. In order to overcome both problems, higher engine out NOx emission and lower exhaust gas temperatures, close-coupled a diesel particulate filter (DPF) system with integration of SCR catalyst technology is preferred. For SCR catalyst activity, it is known that the catalyst loading amount has an influence on NOx performance, so a high SCR catalyst loading will be required.
Journal Article

Development of New High Porosity Diesel Particulate Filter for Integrated SCR Technology/Catalyst

2015-04-14
2015-01-1017
Since the implementation of Euro 6 in September 2014, diesel engines are facing another drastic reduction of NOx emission limits from 180 to only 80 mg/km during NEDC and real driving emissions (RDE) are going to be monitored until limit values are enforced from September 2017. Considering also long term CO2 targets of 95 g/km beyond 2020, diesel engines must become cleaner and more efficient. However, there is a tradeoff between NOx and CO2 and, naturally, engine developers choose lower CO2 because NOx can be reduced by additional devices such as EGR or a catalytic converter. Lower CO2 engine calibration, unfortunately, leads to lower exhaust gas temperatures, which delays the activation of the catalytic converter. In order to overcome both problems, higher NOx engine out emission and lower exhaust gas temperatures, new aftertreatment systems will incorporate close-coupled DeNOx systems.
Technical Paper

Newly Developed Cordierite Honeycomb Substrate for SCR Coating Realizing System Compactness and Low Backpressure

2012-04-16
2012-01-1079
Ammonia Selective Catalytic Reduction (SCR) and Lean NOx Trap (LNT) systems are key technologies to reduce NOx emission for diesel on-highway vehicles to meet worldwide tighter emission regulations. In addition DeNOx catalysts have already been applied to several commercial off-road applications. Adding the DeNOx catalyst to existing Diesel Oxidation Catalyst (DOC) and Diesel Particulate Filter (DPF) emission control system requires additional space and will result in an increase of emission system back pressure. Therefore it is necessary to address optimizing the DeNOx catalyst in regards to back pressure and downsizing. Recently, extruded zeolite for DeNOx application has been considered. This technology improves NOx conversion at low temperature due to the high catalyst amount. However, this technology has concerned about strength and robustness, because the honeycomb body is composed of catalyst.
Technical Paper

High Porosity DPF Design for Integrated SCR Functions

2012-04-16
2012-01-0843
Diesel engines are more fuel efficient due to their high thermal efficiency, compared to gasoline engines and therefore, have a higher potential to reduce CO2 emissions. Since diesel engines emit higher amounts of Particulate Matter (PM), DPF systems have been introduced. Today, DPF systems have become a standard technology. Nevertheless, with more stringent NOx emission limits and CO2 targets, additional NOx emission control is needed. For high NOx conversion efficiency, SCR catalysts technology shows high potential. Due to higher temperature at the close coupled position and space restrictions, an integrated SCR concept on the DPFs is preferred. A high SCR catalyst loading will be required to have high conversion efficiency over a wide range of engine operations which causes high pressure for conventional DPF materials.
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