Procedure for metering a reagent and device for implementing the procedure
US8567181B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 29, 2009 |
| Grant date | Oct 29, 2013 |
| Priority date | — |
| Expiry date | Mar 8, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A procedure for metering a reagent into an exhaust duct of a combustion engine, which is required for a catalytic conversion of NOx in a SCR-catalyzer and a device for implementing the procedure are suggested. Determined is the difference between a calculated and a measured NOx-concentration each downstream after the SCR-catalyzer. The difference is compared to a difference threshold. After an exceeding of the difference threshold a lowering of the metering rate on to a sinking metering rate is undertaken, which is higher than zero. After a waiting time, a comparison of the calculated and the measured NOx-concentration is provided each downstream after the SCR-catalyzer. If the measured NOx-concentration is above the calculated NOx-concentration the metering rate is increased. If the measured NOx-concentration is below the calculated NOx-concentration the metering rate is lowered. The approach according to the invention enables an adaptation of the metering, at which it is ensured that a NOx-conversion can always take place.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.