California Air Resources Board (CARB) publishes paper on Selective Catalytic Reduction (SCR) testing

Niels Tholen - 20 September 2013

California Air Resources Board (CARB) has published a paper on Selective Catalytic Reduction (SCR) performance during real-time driving conditions. The research team used four vehicles, one with Exhaust Gas Recirculation (EGR) technology and three with SCR technology.

In typical highway driving conditions, emissions from the vehicle equipped with EGR technology were found to be higher than the legal limit while NOx levels from vehicles equipped with SCR met the standard. Under conditions which did not reach optimal temperatures (cold start, low-load, low-speed etc) emission levels were found to be elevated.

The research team has recommended CARB should use World Harmonised Test Cycle (WHTC) conditions to capture real-time driving conditions and record more accurate readings. They also advised an alternative to these testing conditions could be the use of PEMS testing combined with OBD monitoring or data broadcasting.

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