US5831267A
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US
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Method and apparatus for remote measurement of exhaust gas
Assignee: ENVIRONTEST SYSTEMS CORP
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Filing: 1997-02-24
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Granted: 1998-11-03
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Expires: 2017-02-24
Abstract
Abstract A method and apparatus for sensing a composition of an exhaust plume includes a light source that radiates an infrared light beam having a plurality of predetermined wavelengths. A first of the predetermined wavelengths is associated with carbon dioxide and a second of the predetermined wavelengths is associated with a second gas, such as a hydrocarbon or carbon monoxide. The apparatus also includes a detector unit that detects the beam passing through the plume. The apparatus computes a ratio of the second gas to carbon dioxide based upon the first and second detected wavelengths, and this ratio is then multiplied by a predetermined estimation of a concentration of carbon dioxide in the plume.
Inventors
- 👤 Michael D. Jack
- 👤 Jay C. Peterson
- 👤 David R. Nelson
- 👤 Michael N. Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:18
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504; G01N2021/1793
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
121 words
An apparatus for sensing a composition of an exhaust plume, comprising: a light source that radiates an infrared light beam through said plume, said beam including a plurality of predetermined wavelengths; a detector that detects said beam passing through said plume at said predetermined wavelengths, wherein a first of said predetermined wavelengths is associated with carbon dioxide and a second of said predetermined wavelengths is associated with a second gas; means for computing a ratio of said second gas to carbon dioxide based upon said first and second detected wavelengths; and a multiplier that multiplies said ratio by a predetermined estimation of a concentration of carbon dioxide in said plume, to provide a measurement of a concentration of said second gas.
Claim 2
Independent Claim
121 words
An apparatus for sensing a composition of an exhaust plume, comprising: a light source that radiates an infrared light beam through said plume, said beam including a plurality of predetermined wavelengths; a detector that detects said beam passing through said plume at said predetermined wavelengths, wherein a first of said predetermined wavelengths is associated with carbon dioxide and a second of said predetermined wavelengths is associated with a second gas; means for computing a ratio of said second gas to carbon dioxide based upon said first and second detected wavelengths; and a multiplier that multiplies said ratio by a predetermined estimation of a concentration of carbon dioxide in said plume, to provide a measurement of a concentration of said second gas.
Claim 3
Dependent Claim
12 words
The apparatus of claim 1, wherein: said second gas is a hydrocarbon.
Claim 4
Dependent Claim
12 words
The apparatus of claim 1, wherein: said second gas is carbon monoxide.
Claim 5
Dependent Claim
14 words
The apparatus of claim 1, wherein: said second gas is an oxide of nitrogen.
Claim 6
Dependent Claim
12 words
The apparatus of claim 1, wherein: said second gas is nitric oxide.
Claim 7
Dependent Claim
31 words
The apparatus of claim 1, wherein: said predetermined estimation of carbon dioxide is in a range of about 13 percent to about 18 percent based upon the volume of the plume.
Claim 8
Dependent Claim
32 words
The apparatus of claim 1, wherein: said predetermined estimation of carbon dioxide is in a range of about 14 percent to about 16 percent based upon the dry volume of the plume.
Claim 9
Dependent Claim
32 words
The apparatus of claim 1, wherein: said predetermined estimation of carbon dioxide is in a range of about 12 percent to about 14 percent based upon the wet volume of the plume.
Claim 10
Dependent Claim
30 words
The apparatus of claim 1, wherein: said detector comprises a plurality of photodetectors, each photodetector being sensitive to a band of wavelengths that includes only one of said predetermined wavelengths.
Claim 11
Dependent Claim
33 words
The apparatus of claim 1, wherein each detector comprises a photosensitive element and a filter disposed between said plume and the photosensitive element having a passband coinciding with a respective band of wavelengths.
Claim 12
Dependent Claim
18 words
The apparatus of claim 1, wherein said predetermined estimation of a concentration of carbon dioxide is experimentally obtained.
Claim 13
Dependent Claim
29 words
The apparatus of claim 1, wherein said second gas is a hydrocarbon, further comprising: a multiplier that multiplies said measurement of concentration of hydrocarbon by an experimentally determined factor.
Claim 14
Dependent Claim
83 words
The apparatus of claim 1, wherein said second gas is a hydrocarbon and a third of said predetermined wavelengths is associated with nitrogen oxide, further comprising: means for computing a ratio (R NO/CO .sbsb.2) of said nitrogen oxide to carbon dioxide based upon said first and third detected wavelengths; and a multiplier that multiplies said ratio (R NO/CO .sbsb.2) by said predetermined estimation of a concentration of carbon dioxide in said plume, to provide a measurement of a concentration of said nitrogen oxide.
Claim 15
Dependent Claim
112 words
The apparatus of claim 1, wherein said exhaust plume is produced by burning a fuel and wherein said second gas is a hydrocarbon and a third of said predetermined wavelengths is associated with carbon monoxide, further comprising: means for computing a second ratio (R CO/CO .sbsb.2) of carbon monoxide to carbon dioxide based upon said first and third detected wavelengths; and means for computing a concentration of said carbon monoxide in said plume from said first ratio and said second ratio (R CO/CO .sbsb.2) based upon an assumption of a first C:H ratio of fuel and a second C:H ratio of the exhaust plume, said first and second C:H ratios being different.
Claim 16
Dependent Claim
21 words
The apparatus of claim 14, wherein: said first C:H ratio is about 1.85 and said second C:H ratio is about 2.33.
Claim 17
Independent Claim
116 words
A method of sensing a composition of an exhaust plume from a moving vehicle, comprising the steps of: radiating an infrared light beam through said plume, said beam including a plurality of predetermined wavelengths; detecting said beam passing through said plume at said predetermined wavelengths, wherein a first of said predetermined wavelengths is associated with carbon dioxide and a second of said predetermined wavelengths is associated with a second gas; computing a ratio of said second gas to carbon dioxide based upon said first and second detected wavelengths; and multiplying said ratio by a predetermined estimation of a concentration of carbon dioxide in said plume, to provide a measurement of the concentration of said second gas.
Claim 18
Independent Claim
116 words
A method of sensing a composition of an exhaust plume from a moving vehicle, comprising the steps of: radiating an infrared light beam through said plume, said beam including a plurality of predetermined wavelengths; detecting said beam passing through said plume at said predetermined wavelengths, wherein a first of said predetermined wavelengths is associated with carbon dioxide and a second of said predetermined wavelengths is associated with a second gas; computing a ratio of said second gas to carbon dioxide based upon said first and second detected wavelengths; and multiplying said ratio by a predetermined estimation of a concentration of carbon dioxide in said plume, to provide a measurement of the concentration of said second gas.
Claim 19
Dependent Claim
12 words
The method of claim 16, wherein: said second gas is carbon monoxide.
Claim 20
Dependent Claim
12 words
The method of claim 16, wherein: said second gas is a hydrocarbon.
Claim 21
Dependent Claim
26 words
The method of claim 16, wherein said second gas is a hydrocarbon, further comprising: multiplying said measurement of concentration of hydrocarbon by an experimentally determined factor.
Claim 22
Dependent Claim
14 words
The method of claim 16, wherein: said second gas is an oxide of nitrogen.
Claim 23
Dependent Claim
12 words
The method of claim 16, wherein: said second gas is water vapor.
Claim 24
Dependent Claim
29 words
The method of claim 16, wherein: said predetermined estimation is in a range of about 13 percent to about 18 percent based upon the volume of the exhaust plume.
Claim 25
Dependent Claim
30 words
The method of claim 16, wherein: said predetermined estimation is in a range of about 14 percent to about 16 percent based upon the dry volume of the exhaust plume.
Claim 26
Dependent Claim
30 words
The method of claim 16, wherein: said predetermined estimation is in a range of about 12 percent to about 14 percent based upon the wet volume of the exhaust plume.
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