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A catalytic deSoot-deNOx system, comprising Pt and Ce fuel additives, a Pt impregnated wall-flow monolith soot filter and a vanadia-type monolithic NH3 - SCR catalyst, was tested with a 2 cylinder DI diesel engine. The soot removal efficiency of the filter was 98-99% (mass), the balance temperature (stationary pressure drop) was 315 °C at an engine load of 55%. The NOx-emission at high loads is around 15% lower than those of engine running without fuel additives. The NOx conversion ranged from 40 to 73%, at a NH3/NOx ratio of 0.9, both measured at a GHSV of 52,000 l/l/h. The maximum NOx conversion was obtained at 400 °C. No deactivation was observed after 380 h time on stream.

The physical state of a heterogeneous soot oxidation catalyst has a big impact on their performance. Contact between soot and solid catalysts is one of the key parameters for soot oxidation. Catalyst formulations based on low eutectic melting points were studied. Formulation based on cesiumsulfate and vanadiumoxide, became active at their melting point of 320-350 °C. Ceramic foam can act as support for the liquid catalyst as well as a deep filter for the soot. Downstream of a small diesel engine a balance temperature of 350 °C was established with an initial trapping efficiency of 40 %. Stable pressure drop over the system was maintained over a period of more than 24 hours.

In laboratory engine tests, a combination of platinum and cerium fuel additives with a platinum activated wall flow monolithic filter has been shown to be especially effective in the control of diesel particulate. Continuous regeneration of a filter can be achieved at temperatures of 600 K using 5 ppm of cerium and 0.5 ppm of platinum in EN590 fuel containing 500 ppm (wt) of sulfur.