Urea injection systems for diesel vehicles might soon be less expensive thanks to a recent ruling in a European patent case. Daimler was part owner of a patent covering selective catalytic reduction systems for diesel engines. The SCR systems use urea injected into the exhaust stream along with a special catalytic converter to transform NOx emissions into nitrogen and water. The original patent was filed by British supplier Johnson Matthey with later filings from Daimler and Umicore.
Daimler eventually took a partial ownership stake in the Johnson Matthey patent that was granted first in Europe and later in the U.S. Umicore, which makes catalytic converters including the SCR units used by Mercedes, challenged the patent and the European patent office overturned it on the grounds that as written, it only covered a particular configuration of parts rather than the concept as well as the presence of prior art. A U.S. challenge is still pending, but Daimler won't be able to collect any royalties on the technology in Europe and may abandon hopes of doing so here as well.