Method for determining a NOx concentration
US6699383B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 2002 |
| Grant date | Mar 2, 2004 |
| Priority date | — |
| Expiry date | May 28, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/4074
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A thick-film measurement sensor includes two measurement cells and is used to measure the NOx concentration in the exhaust gas from an internal combustion engine. The 1/&lgr; value of the exhaust gas is determined from an oxygen ion pump current flowing in the first measurement cell, for example, by a characteristic diagram, and, a measurement error, which can be used to correct the measured NOx concentration, is determined from this 1/&lgr; value, for example, by a characteristic curve that has previously been determined in a calibration measurement. The invention is based on the discovery that the measurement error is dependent on the air ratio in the exhaust gas. If this is expressed by the 1/&lgr; value, there is no need for a complex division calculation during the correction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.