NOx concentration measuring apparatus
US4988428A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1990 |
| Grant date | Jan 29, 1991 |
| Priority date | — |
| Expiry date | May 15, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A50/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An NOx concentration measuring apparatus employing first and second wide-range air/fuel ratio sensors for measuring an NOx concentration of gases introduced thereto through a first passage. First and second restricted orifices are provided in the first passage upstream of the first and second sensors. A second passage is connected to the first passage between the first and second orifices. A suction pump is connected to the first passage downstream of the first and second sensors for producing a suction vacuum in the first passage and is also connected to the second passage for producing a suction vacuum in the second passage. The first and second orifices are effective to prevent momentary gas pressure fluctuations from affecting the accuracy of measurement of the first and second sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.