Optical sensing apparatus for remotely measuring exhaust gas composition of moving motor vehicles
US5591975A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1994 |
| Grant date | Jan 7, 1997 |
| Priority date | — |
| Expiry date | Oct 5, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A50/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A light source radiates an infrared beam that passes through a chopper, a calibration cell and the exhaust plume of a motor vehicle passing in front of the source. A photosensor assembly includes a plurality of photodetectors which are spaced closely adjacent to each other and simultaneously sense the beam after it propagates through the plume. An optical beam homogenizer or integrator disposed between the plume and the photosensor unit causes the light incident on the photodetectors to have uniform intensity. The photodetectors are sensitive to different wavelengths corresponding to spectral absorption peaks of constituents of the composition of the plume, including carbon monoxide (CO), carbon dioxide (CO.sub.2), hydrocarbon (HC), water vapor (H.sub.2 O) and nitric oxide (NO). A computer computes the composition of the plume as the percentages of the constituents based on the sensed transmittances of the respective wavelengths through the plume. A video camera produces a video image of the vehicle license plate, which is displayed on a video monitor and recorded on a video recorder together with the plume composition data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.