Apparatus for remote analysis of vehicle emissions

• US 5,210,702 A
• Filed: 12/26/1990
• Issued: 05/11/1993
• Est. Priority Date: 12/26/1990
• Status: Expired due to Term

• Current Assignee: Colorado Seminary
• Original Assignee: Colorado Seminary
• Inventors: Stedman, Donald H., Bishop, Gary
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Cosimano, Edward R.
• Application Number:
  US07/633,952
• Time in Patent Office: 867 Days
• Field of Search: 250/338.5, 250/339, 250/372, 364/496, 364/497, 364/498
• US Class Current: 702/24
• CPC Class Codes: G01N 2021/1793 Remote sensing
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis

Abstract

A gas analysis device for the remote detecting, measuring and recording of NO_x, CO, CO₂, HC and H₂ O levels from the exhaust of moving motor vehicles. It utilizes a source of collimated infrared and ultraviolet radiation and includes a mechanism for receiving and measuring the infrared and ultraviolet radiation from its source, and another mechanism for measuring background infrared and ultraviolet radiation levels in the ambient atmosphere. The receiving mechanism splits the combined infrared and ultraviolet radiation into separate infrared and ultraviolet beams. A mechanism receives the separate ultraviolet beam and generates a signal indicative of NO_x. Another mechanism splits the infrared beam into two to four components, and devices are positioned for receiving each of the infrared components and generating two to four signals indicative of, for example, CO, CO₂, HC and H₂ O. Another associated mechanism then computes and produces signals indicative of the amount of CO, CO₂, HC, NO_x and H₂ O in the path of the infrared and ultraviolet radiation from the source, thereby making it capable of measuring emissions of vehicles. The source and the receiving mechanism are aligned on opposite sides of a roadway, both being at the elevation of the to-be-measured vehicle exhaust. Vehicles traveling on that roadway and passing through the radiation emanating from the source interrupt reception of the beam by the detector, thereby initiating a detection sequence. In one embodiment a visual recording device is positioned for visually recording the vehicle and test results.

Claims

1. A gas analysis device for detecting and measuring levels of gases in the exhaust of moving motor vehicles in the ambient atmosphere selected from the group consisting of carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxides and water vapor levels, said device comprising:

a. source means for producing collimated infrared and ultraviolet radiation and transmitting such radiation through a portion of said motor vehicle exhaust;

b. means for splitting said infrared and ultra-violet radiation into separate infrared and ultraviolet beams;

c. means for receiving said ultraviolet beam and generating a first electrical signal indicative of the absorption of ultraviolet radiation by nitrogen oxides in said exhaust;

d. means for splitting said infrared beam into at least two separate infrared beam components;

e. means for receiving a first infrared beam component and generating a second electrical signal indicative of the absorption of said infrared beam by carbon dioxide in said exhaust;

f. means for receiving a second infrared beam component and generating at least a third electrical signal therefrom indicative of the absorption of said infrared beam by gases in said exhaust selected from the group consisting of carbon monoxide, hydrocarbons and water vapor; and

g. means responsive to said electrical signals for computing and producing output signals indicative of the amount of gases selected from the group consisting of carbon monoxide, hydrocarbons and water in the path of said collimated infrared and ultraviolet radiation in said exhaust.

2. The device as claimed in claim 1, wherein said infrared beam splitting means further includes means for splitting said beam into a third infrared beam component, and wherein said device further includes means for receiving said third infrared beam component and generating a fourth electrical signal indicative of the absorption of said infrared beam by a fourth gas selected from the group consisting of carbon monoxide, hydrocarbons and water vapor, said electrical signal responsive means further including means responsive to said fourth electrical signal for computing and producing an output signal indicative of the amount of said fourth gas in the path of said collimated beam in said exhaust.

3. The device as claimed in claim 1, wherein said infrared beam splitting means further includes means for splitting said beam into a third infrared beam component, and wherein said device further includes means for receiving said third infrared beam component and generating a fourth electrical signal indicative of the absorption of said infrared beam by a fourth gas selected from the group consisting of carbon monoxide, hydrocarbons and water vapor, said electrical signal responsive means further including means responsive to said fourth electrical signal for computing and producing an output signal indicative of the amount of said fourth gas in the path of said collimated beam in said exhaust.

4. The device as claimed in claim 1, wherein said infrared beam component detection means is selected from the group consisting of liquid nitrogen cooled, indium antimonide photovoltaic detector units and lead selenide detector units operated at or below ambient temperature.

5. The device as claimed in claim 1, wherein said ultraviolet beam detection means comprises an ultraviolet photomultiplier.

6. The device as claimed in claim 1, wherein said device includes means for splitting said ultraviolet beam into an ultraviolet detection beam and an ultraviolet reference beam.

7. The device as claimed in claim 1, wherein said means for splitting said infrared beam and said ultra-violet beam includes a dichroic beamsplitter constructed to bend the ultraviolet beam at a considerable angle relative to bending of the infrared beam, thereby separating said infrared and ultraviolet beams.

8. The device as claimed in claim 1, wherein said means for splitting said infrared beam and said ultra-violet beam includes a calcium fluoride beamsplitter constructed to reflect the ultraviolet beam at a considerable angle relative to the transmission of the infrared beam, thereby separating said infrared and ultraviolet beams.

9. The device as claimed in claim 1, wherein said means for splitting said infrared beam into at least two separate infrared beam components comprises a rotation polygonal structure having a mirror on each side, whereby the infrared beam is directed sequentially onto at least two separate infrared detector systems.

10. A gas analysis system for the remote sensing, measuring and recording of carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxide and water vapor levels in the exhaust of moving motor vehicles, said system comprising;

a. means for generating and directing a collimated beam of infrared and ultraviolet radiation across an open space of sufficient size to permit passage of moving vehicles therethrough;

b. detector means for receiving said collimated infrared and ultraviolet beam and producing in response thereto a first electrical signal indicative of the absorption of said beam radiation by nitrogen oxides, a second electrical signal indicative of the absorption of said beam radiation by carbon monoxide, a third electrical signal indicative of the absorption of said beam radiation by carbon dioxide, a fourth electrical signal indicative of the absorption of said beam radiation by hydrocarbons, a fifth electrical signal indicative of the absorption of said beam radiation by water, and a sixth electrical signal indicative of the total absorption of said beam radiation in said open space between said beam generating means and said detection means, said beam generating means and said detector means being aligned at a elevation such that a moving vehicles passing through such open space interrupts reception of said collimated beam by said detector means by blocking said beam;

c. means responsive to said electrical signals for computing and producing output signals indicative of the amount of nitrogen oxides, carbon monoxide, carbon dioxide and hydrocarbons in the path of said collimated beam in said open space;

d. memory storage means for storing said output and signal information prior to beam interruption;

e. means for sampling said electrical signals and corresponding output signals for from about 0.1 to about 1.0 second after resumption of collimated beam reception by said detector means; and

f. means for correlating and comparing said output signals before and after beam interruption to determine any increase of nitrogen oxides, carbon monoxide, carbon dioxide, hydrocarbons and water vapor levels in the open space due to the exhaust of the moving vehicle responsible for beam interruption as well as for calculating and providing ratios of all tested species to carbon dioxide for the exhaust of said vehicles.

11. The system as claimed in claim 10, wherein said detection means includes means for measuring the background infrared and ultraviolet radiation levels in the said open space for providing reference calibration signals to monitor the total infrared and ultraviolet beam intensities for comparison with said electrical signals generated by said computing means to provide said output signals.

12. The system as claimed in claim 10, wherein said detection means includes a prism for splitting said infrared and ultraviolet radiation into two separate beams within said detection means, an infrared beam splitter means for dividing said infrared beam into four separate infrared beam paths within said detection means, a ultraviolet detection unit aligned to receive said ultraviolet beam, and four separate infrared detection units aligned to receive said four infrared beam paths, each said infrared detection unit including a band pass filter member to isolate, respectively, carbon monoxide, carbon dioxide, hydrocarbons and water spectral regions from said split beam paths to provide said second, third, fourth and fifth electrical signals.

13. The system as claimed in claim 10, wherein said system further includes computing means including a memory for continuously sampling all infrared and ultraviolet beam intensities received by said detector means and includes means for computing the ratios of the carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxide and water voltages to reference voltages and rescaling these units into calibrated carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxide and water values data.

14. The system as claimed in claim 13, wherein said computing means further includes means for analyzing said values to determine the path independent CO/CO₂ ratio as well as the other gas/CO₂ ratios.

15. The system as claimed in claim 10, wherein said system further includes means positioned along said open space, spaced from said detector means and orientated for visually recording for identification the end portion of a moving vehicle as it passes through said open space and interrupts the reception of said collimated beam by said detector means;

means for visually monitoring the output of said visually recording means while simultaneously displaying said nitrogen oxide, carbon monoxide, carbon dioxide, hydrocarbons and water level information available from said correlation means in conjunction with the exhaust of the same moving motor vehicle; and

means for storing the information displayed on said monitor means.

17. The system as claimed in claim 15, wherein said monitoring means includes a visual monitor device connected to said correlation means to display the output of said video camera simultaneously with the output of said correlation means to provide on line information of levels in the exhaust of the identified vehicle.

18. The system as claimed in claim 17, wherein said storing means comprises a video recording device to store the display of said monitor device.

16. The system as claimed in 15, wherein said visual recording means comprises a video camera aligned to record the end portion of said moving vehicle, including any vehicle identification material displayed on said moving vehicle, as said vehicle interrupts the reception of said collimated beam by said detector means.