PM reduction over vanadium SCR

Emission limits and legislative boundaries at the On-Road and Off-Road applications are steadily tightened. Beside Europe and the USA even at the BRICS states (Brazil, Russia, India, China, South Africa) a stricter legislation is visible.The limits of carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO_x) and particulate matter (PM) are strictly lowered. Optimization of engine parameters like EGR and injection technology is not sufficient. Adapted exhaust gas aftertreatment (EGA) systems have to be used to reach the targets. A combination of different catalyst systems is suitable.Recent EU VI systems use particle filters, Diesel oxidation catalysts (DOC) as well as lean NO_x trap catalysts or SCR systems. For emerging markets, the combination of increased mobility requirements and the need of cheap and resilient exhaust gas aftertreatment systems lead to SCR-only systems based on vanadium (V-SCR). Beside the positive effect of low costs, vanadium SCR systems show a positive particulate emission reducing effect under different circumstances. The observed values for PM and hydrocarbons present significant reductions, but this property has not yet been adequately studied and understood. CO₂ is the favored outcome after oxidation, but also CO and byproducts of partial oxidation can been found.It was shown that especially smaller particles are preferably reduced by the oxidation at the V-SCR. This is advantageous because studies arise that small particles seem to be more harmful to human health. A high efficiency application of the engine shows the best results of the oxidation effect and furthermore low tailpipe emissions of TPM, NO_x and CO₂, which leads to an additional benefit for a possible series application.