NOx Emissions Control for Euro 6

The control of oxides of nitrogen (NOx) emissions to meet more stringent motor vehicle emission legislation has been enabled by the development of various exhaust gas aftertreatment technologies, notably those that employ platinum group metals (pgms). New legislation in force for European heavy-duty diesel vehicles from 2013, light-duty diesels from 2014 and some non-road diesel engines from 2014 requires a further reduction of NOx emissions. The proposed enforcement of a particulate number limit for gasoline engines in Europe also presents challenges by requiring control of PM to extremely low levels in addition to keeping emissions of other pollutants at minimal levels. One possibility is to use a filter coated with similar material to a TWC as part of the overall aftertreatment system. For gasoline engines, new on-board diagnostic limits that come into force at Euro 6 part 2 in 2017 reduce by 70% the threshold amount of NOx emitted before the driver is notified of a problem with the catalyst.