Sampling system for exhaust gas sensors and method of using same

• US 20030172741A1
• Filed: 01/29/2003
• Published: 09/18/2003
• Est. Priority Date: 01/29/2002
• Status: Active Grant

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Busch, Michael-Rainer
• Granted Patent: US 6,843,104 B2
• Time in Patent Office: Days
• US Class Current: 73/861.21
• CPC Class Codes: G01N 1/2252 in a vehicle exhaust
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 2001/2264 with dilution
• CPC Class Codes: G01N 33/0011 Sample conditioning in general G01N1/28

Abstract

A system is provided for measuring gaseous constituents of a flowing gas mixture, having a gas flow control device and at least one sensor which is in contact with the flowing gas mixture. At least one mixing device is placed in the flow of the gas mixture, which mixing device homogenizes the gas mixture to mixed gas before it is detected by the sensor. The system is adapted for use in exhaust gas systems of internal-combustion engines.

Claims

1. System for measuring gaseous constituents of a flowing gas mixture comprising:

a gas flow control device;

at least one sensor which is in use in contact with the flowing gas mixture; and

at least one mixing device inserted in a flow of the gas mixture, which mixing device in use homogenizes the gas mixture to mixed gas before it is detected by the sensor.

2. System according to claim 1, wherein the mixing device is operable to homogenize between 1% and 100%, of the gas mixture flowing in the gas flow control device;

and

wherein the mixing device feeds between 10% and 90% of the mixed gas to the sensor.

3. System according to claim 2, wherein the mixing device is operable to homogenize approximately 20% of the gas mixture flowing in the gas flow control device.

4. System according to claim 1, wherein the mixing device is provided on one of:

(i) the entire diameter of the gas flow control device;

(ii) at a distance from an interior wall area to into an area of the center axis; and

(iii) along the entire inner circumference of the gas flow control device.

5. System according to claim 2, wherein the mixing device is provided on one of:

(i) the entire diameter of the gas flow control device;

(ii) at a distance from an interior wall area to into an area of the center axis; and

(iii) along the entire inner circumference of the gas flow control device.

6. System according to claim 1, wherein the cross-sectional surface of the mixing device perpendicular to the flow direction amounts to between 5% and 90% of the flow cross-section of the gas flow control device.

7. System according to claim 1, wherein the mixing device is inserted through the housing wall of the gas flow control device.

8. System according to claim 6, wherein the cross-sectional surface of the mixing device perpendicular to the flow direction amounts to approximates 15% of the flow cross section of the gas flow control device.

9. System according to claim 1, wherein the mixing device has at least one inlet opening and at least one outlet opening;

and

wherein a guiding device is provided between the inlet opening and the outlet opening, which guiding device deflects the gas mixture received through the inlet openings in its flow direction.

10. System according to claim 2, wherein the mixing device has at least one inlet opening and at least one outlet opening;

and

wherein a guiding device is provided between the inlet opening and the outlet opening, which guiding device deflects the gas mixture received through the inlet openings in its flow direction.

11. System according to claim 6, wherein the mixing device has at least one inlet opening and at least one outlet opening;

and

wherein a guiding device is provided between the inlet opening and the outlet opening, which guiding device deflects the gas mixture received through the inlet openings in its flow direction.

12. System according to claim 1, wherein the system exhibits at least one of the following features:

a) the cross-sections of the inlet openings vary in their shape and size,

b) the cross-sections of the outlet openings vary in their shape and size,

c) the cross-sectional surfaces of the mixing device perpendicular to the flow direction vary in the shape and the size,

d) the cross-sections of the mixing device parallel to the flow direction vary in their shape and size,

e) the inlet openings vary in their inlet spacing with respect to one another,

f) the inlet openings are formed by pores,

g) the outlet openings are formed by pores.

13. System according to claim 1, wherein the size, the shape and the inlet spacing of the inlet openings vary with respect to one another as a function of the distance of the respective inlet openings from the sensor.

14. System according to claim 1, wherein the size, the shape and the outlet spacing of the outlet openings vary with respect to one another as a function of the distance of the respective outlet openings from the sensor.

15. System according to claim 13, wherein the size, the shape and the outlet spacing of the outlet openings vary with respect to one another as a function of the distance of the respective outlet openings from the sensor.

16. System according to claim 1, wherein the surface forming at least one of the inlet openings and the outlet openings of the mixing device is formed of one of metal and ceramics.

17. System according to claim 1, wherein the mixing device accommodates the sensor and/or is inserted together with the sensor into the gas flow control device and can be exchanged together with the sensor.

18. System according to claim 9, wherein in addition to the guiding device, the mixing device has at least one baffle plate which is situated on the outside and which guides the gas mixture into the inlet openings.

19. System according to claim 1, wherein the mixing device can be heated by a heating device or receives a heating device.

20. System according to claim 1, wherein the flowing gas mixture is an exhaust flow mixture from a combustion engine.

21. A method of using the system of claim 1, for measuring an exhaust flow mixture from a combustion engine.

25. A system according to claim 2, wherein the cross-sectional surface of the mixing device perpendicular to the flow direction amounts to between 5% and 90% of the flow cross-section of the gas flow control device.

22. A system for measuring gas constituents of an exhaust gas flow mixture from a combustion engine of a motor vehicle comprising:

a gas flow control device;

at least one sensor which is in use in contact with the flowing gas mixture; and

at least one mixing device inserted in a flow of the gas mixture, which mixing device in use homogenizes the gas mixture to mixed gas before it is detected by the sensor.

23. A system according to claim 22, wherein the mixing device is operable to homogenize between 1% and 100%, of the gas mixture flowing in the gas flow control device;

and wherein the mixing device feeds between 10% and 90% of the mixed gas to the sensor.

24. A system according to claim 23, wherein the mixing device is operable to homogenize approximately 20% of the gas mixture flowing in the gas flow control device.