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The emission limitations for heavy-duty vehicles are coming stricter between 2005 - 2008 in Europe, Japan and United States. In addition to engine, fuel and control modifications, efficient exhaust gas after treatments like oxidation/deNOx catalysts and particulate filters are needed. In mobile truck applications the system should operate at low (<300°C) and stand high temperatures (500-650°C) in transient driving conditions. Coated V2O5/TiO2-WO3 based SCR catalysts on thin metal foil substrates have been studied here in laboratory and engine experiments. The open-coating method enables the high volumetric amount of SCR catalyst evenly coated on high cell density substrates (e.g. 600 cpsi). A new washcoat composition with platinum loading has been used in pre-oxidation catalyst to reach the NO2 concentrations, which initiate the SCR reaction clearly below 300°C.

The development of efficient, durable three-way catalysts with OBD facilities needs cooperation between different areas related to engine, control and catalyst technologies. High-loading Pd and Pd-Rh precatalysts with λ sensors upstream and downstream were evaluated in FTP cycle to find out the appropriate driving conditions for OBD-II. Diagnostic values were calculated by the damping of λ responses caused by the aged precatalyst. The ratio of oxygen storage capacity (OSC) and precious metals were studied to improve the correlation between calculated diagnostic values and the catalyst efficiency. In fact, the correlation from diagnostic values was better to NOx than to THC efficiency by bag 1 and 2 emissions in FTP 75. The amplitude method with two λ sensors over warm converters is commonly used for OBD but hydrocarbon emissions are mainly formed during cold-start periods. Therefore the OBD calibration and catalyst optimal compositions have conflicting demands.