Method and apparatus for measuring NOx gas concentration
US6214208A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1997 |
| Grant date | Apr 10, 2001 |
| Priority date | — |
| Expiry date | Dec 2, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/179228
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This is a method and apparatus for accurately determining a NOx concentration of a measurement gas that contains H.sub.2 O and/or CO.sub.2, without being affected by a dissociation of H.sub.2 O and/or CO.sub.2. In this method and apparatus, PA1 (1) the NOx-measurement gas containing H.sub.2 O and/or CO.sub.2 is introduced to travel through a heated flow channel formed by an oxygen ion conductive solid ceramic electrolyte body that electrically control amount of O.sub.2 from the flow channel, PA1 (2) while said measurement gas travels, a residual gas including NO and H.sub.2 O and/or CO.sub.2 is formed from the measurement gas, PA1 (3) said residual gas is flowed to contact a catalytic electrode to which a negative polarity of a low voltage that does not dissociate H.sub.2 O and/or CO.sub.2 but dissociates NO is applied, so that said electrode dissociates a NO gas of the residual gas into N ions and O ions and flows an electric current through the electrolyte body in proportion to an amount of the O ions dissociated from said residual gas at the electrode, and PA1 (4) the NOx concentration in the measurement gas is determined based on the current. The low voltage preferably applied …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.