Optical path structure for open path emissions sensing with particulate matter and lubricating oil consumption absorption methodology

• US 6,900,893 B2
• Filed: 05/10/2002
• Issued: 05/31/2005
• Est. Priority Date: 08/21/2001
• Status: Active Grant

• Current Assignee: SPX Corporation
• Original Assignee: SPX Corporation
• Inventors: Rendahl, Craig S., Foley, Theresa A., Gentala, Robert A., DiDomenico, John
• Primary Examiner(s): Pham, Hoa Q.
• Application Number:
  US10/142,061
• Publication Number:
  US 20030058451A1
• Time in Patent Office: 1,117 Days
• Field of Search: 356432-440, 356335-343, 250/339.01, 250/339.05, 250/338.1, 250/338.5, 250/336.1, 250/339.13, 250/372, 250/339.11, 250/343, 250/345, 73/10.6
• US Class Current: 356/437
• CPC Class Codes: G01M 15/108 using optical methods
• CPC Class Codes: G01N 1/2252 in a vehicle exhaust
• CPC Class Codes: G01N 2001/2264 with dilution
• CPC Class Codes: G01N 2021/3155 Measuring in two spectral ranges, e.g. UV and visible
• CPC Class Codes: G01N 2021/3174 Filter wheel
• CPC Class Codes: G01N 2021/3513 Open path with an instrumental source
• CPC Class Codes: G01N 2021/3527 and using one filter cell as attenuator
• 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
• CPC Class Codes: G01N 21/534 by measuring transmission alone, i.e. determining opacity

Abstract

A device for measuring particulate matter includes a light source that emits light, a receiver positioned to receive light emitted from the light source, and a detection unit in communication with the receiver. The detection unit detects an amount of particulate matter based upon the light received by the receiver.

Claims

1. A device for measuring particulate matter comprising:

a light source that emits light;

a receiver positioned to receive light emitted from said light source; and

a detection unit in communication with said receiver wherein said detection unit detects an amount of particulate matter based upon said light received by said receiver

wherein said detection unit determines the concentration of particulate matter using the relationship;

$C=\frac{2-{\mathrm{Log}}_{10}<br><br>\left(\frac{I_p}{I_o}\times <br><br>100\right)}{\mathrm{\varepsilon <br><br>}\times <br><br>l}.$

wherein

I_p is the amount of light after passing through the gas sample of interest;

I_o is the amount of light that was originally sent through the entire sample path and not absorbed by the gas of interest;

ε

is the absorption coefficient for the gas of interest at a corresponding wavelength of absorption; and

l is the path length.

2. The device as recited in claim 1 wherein said light source emits light at wavelengths in the visible spectrum.

3. The device as recited in claim 1 wherein said light source emits light at al wavelength of 500 nanometers.

4. The device as recited in claim 1 wherein said detection unit determines the concentration of particulate matte by determining a concentration of particulate matter and scaling said concentration.

5. The device as recited in claim 1 further comprising a reflector positioned to receive said light emitted from said light source and to reflect said light to said receiver.

6. The device as recited in claim 1 further comprising:

a beam splitter/combiner positioned to receive light emitted from said light source; and

additional light sources positioned to emit light to said beam splitter/combiner so that the path of light emitted from said additional light sources follows the same optical path as said light emitted from said light source.

7. A method for determining a concentration of particulate matter comprising the steps of:

emitting light from a light source;

receiving said light emitted from said light source in a receiver;

determining an amount of particulate matte using said light received in said receiver;

wherein the step of determining an amount of particulate matter further comprises the step of suing the relationship;

$C=\frac{2-{\mathrm{Log}}_{10}<br><br>\left(\frac{I_p}{I_o}\times <br><br>100\right)}{\mathrm{\varepsilon <br><br>}\times <br><br>l}.$

 

wherein

I_p is the amount of light after passing through the gas sample of interest;

I_o is the amount of light that was originally sent through the entire sample path and not absorbed by the gas of interest;

ε

is the absorption coefficient for the gas of interest at a corresponding wavelength of absorption; and

l is the path length.

8. The method as recited in claim 7 wherein said step of emitting light from said light source comprises the step of emitting light at wavelengths in the visible spectrum.

9. The method as recited in claim 7 wherein said step of emitting light from said light source comprises the step of emitting light at wavelength at 500 nanometers.

10. The method as recited in claim 7 further comprising the step of reflecting said light emitted from said light source to said receiver.

11. The method as recited in claim 7 further comprising the step of reflecting said light emitted from said light source to said receiver.

12. A system for measuring particulate matter comprising:

a light source means for emitting light;

a receiver means for receiving said light emitted from said light source means, said receiver means positioned to receive said light emitted from said light source means; and

a detection unit means for determining an amount of particulate matter based upon the light received by said receiver, said detection unit means in communication with said receiver means;

wherein said detection unit means determines the concentration of particulate matter using the relationship;

$C=\frac{2-{\mathrm{Log}}_{10}<br><br>\left(\frac{I_p}{I_o}\times <br><br>100\right)}{\mathrm{\varepsilon <br><br>}\times <br><br>l}$

 

wherein

I_p is the amount of light after passing through the gas sample of interest;

I_o is the amount of light that was originally sent through the entire sample path and not absorbed by the gas of interest;

ε

is the absorption coefficient for the gas of interest at a corresponding wavelength of absorption; and

l is the path length.

13. The system as recited in claim 12 wherein said light source means emits light at wavelengths in the visible spectrum.

14. The system as recited in claim 12 wherein said light source means emits light at a wavelength of 500 nanometers.

15. The system as recited in claim 12 wherein said detection unit means determines the concentration of particulate matter by determining a concentration of particulate matter and scaling said concentration.

16. The system as recited in claim 12 further comprising a reflector means fro reflecting said light emitted from said light source means to said receiver means.

17. The system as recited in claim 12 further comprising:

a beam splitter/combiner means for receiving light emitted from said light source means; and

an additional light source means for emitting light to said beam splitter/combiner means so that the path of light emitted from said additional light source means follows the same optical path as said light emitted from said light source means.