Particle-based flow sensor

• US 7,549,317 B2
• Filed: 08/09/2007
• Issued: 06/23/2009
• Est. Priority Date: 12/31/2003
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Rhodes, Michael L., Krafthefer, Brian C.
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US11/836,471
• Publication Number:
  US 20070271903A1
• Time in Patent Office: 684 Days
• Field of Search: 73/280.1, 73/280.2, 73/233.1, 731/147.4, 731/146.9, 123/568.16, 123/568.21
• US Class Current: 73/23.31
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: F01N 2560/05 the means being a particulate sensor
• CPC Class Codes: F01N 2560/07 the means being an exhaust gas flow rate or velocity meter or sensor, intake flow meters only when exclusively used to determine exhaust gas parameters
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1445 the characteristics being related to the exhaust flow
• CPC Class Codes: F02D 41/1466 the characteristics being a soot concentration or content
• CPC Class Codes: F02M 26/46 for determining the characteristics of gases, e.g. composition
• CPC Class Codes: F02M 26/47 the characteristics being temperatures, pressures or flow rates
• CPC Class Codes: F02M 26/49 Detecting, diagnosing or indicating an abnormal function of the EGR system
• CPC Class Codes: F02M 26/50 Arrangements or methods for preventing or reducing deposits, corrosion or wear caused by impurities arrangement or layout of EGR passages with means for cleaning or treating the recirculated gases F02M26/35; protection of EGR valves from damage F02M26/74
• CPC Class Codes: G01F 1/7088 using electrically charged particles as tracers
• CPC Class Codes: G01N 15/0656 using electric, e.g. electrostatic methods or magnetic methods by investigating individual particles G01N15/1031, G01N15/12
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A fluid conveyance apparatus having more than one particulate matter sensing probe situated at two or more locations on the apparatus. Signals from the probes from at least two locations may indicate particulate matter flowing within a fluid through the conveyance apparatus. The times between signals may be indicated the rate of movement of the particulate matter in the conveyance apparatus and also a flow rate and direction of the fluid. The sensing probe signals may be processed into control signals that may go to a flow control mechanism. An example application of the flow control mechanism may be for an exhaust gas recirculation system of an engine.

Claims

1. A particulate-based flow sensing system comprising:

a first particulate matter sensor; and

a second particulate matter sensor; and

wherein the first and second sensors include probe electrodes made of 304 type stainless steel, and are positioned at a distance along a path between the first and second sensors, wherein the first and second sensors each have a passivation layer on the electrodes.

2. The system of claim 1, further comprising a processor connected to the first and second sensors, wherein the processor may receive first and second signals from first and second sensors, respectively.

3. The system of claim 2, wherein:

the processor measures a time between the first and second signals; and

the processor divides the distance along the line between the first and second sensors by the time to obtain a rate of movement of the particulate matter.

4. The system of claim 3, wherein:

the particulate matter is in an exhaust gas; and

the rate of movement of the particulate matter is an indication of exhaust gas flow rate.

5. The system of claim 3, wherein processor outputs a flow rate of an exhaust gas containing the particulate matter.

6. The system of claim 2 wherein the signals from the first and second particulate matter sensors indicate a direction of flow of particulate matter through the flow control mechanism.

7. A particulate-based flow system comprising:

a flow control mechanism having an input for connection to an engine exhaust system and an output for connection to an engine intake system;

a first particulate matter sensor situated at a first location at the input of the flow control mechanism; and

a second particulate matter sensor situated at a second location at the input of the flow control mechanism;

a processor connected to the flow control mechanism, the first particulate matter sensor and the second particulate matter sensor, the processor receiving signals from the first and second particulate matter sensors;

wherein the signals from the first and second particulate matter sensors indicate a direction of flow of particulate matter through the flow control mechanism.

8. The system of claim 7, wherein the first and second particulate sensors measure a flow rate of particulate matter.

9. The system of claim 8, wherein the processor adjusts the flow control mechanism in part according to the signals from the first and second particulate matter sensors.

10. The system of claim 7, wherein the first and second sensors include probe electrodes made of 304 type stainless steel.

11. The system of claim 7, wherein:

if the flow of particulate matter is sensed to be from the input to the output of the flow control mechanism, then the flow control mechanism may allow the flow to continue; and

if the flow of particulate matter is sensed to be from the output to the input of the flow control mechanism, then the flow control mechanism may stop the flow.

12. The system of claim 11, wherein the flow control mechanism is an exhaust gas recirculation valve.

13. A method for measuring a flow, comprising:

placing a first particulate matter sensor at a first location in a conveyance mechanism for movement of a fluid containing particulate matter;

placing a second particulate matter sensor at a second location in the conveyance mechanism; and

receiving first and second signals from the first and second particulate matter sensors, respectively, which indicate a flow of a fluid containing particulate matter;

wherein the conveyance mechanism for movement of a fluid containing particulate matter includes a flow control mechanism having an input and an output and the signals from the first and second particulate matter sensors indicate a direction of flow of particulate matter through the flow control sensor.

14. The method of claim 13, further comprising:

measuring a time difference between the first and second signals and a length between the first and second locations; and

calculating the speed of the particulate matter between the first and second locations.

15. The method of claim 14, further comprising determining a flow rate of the fluid in the conveyance mechanism from the speed of the particulate matter.

16. The method of claim 15, wherein the fluid is an exhaust gas of an engine.

17. The method of claim 16, further comprising controlling an exhaust gas recirculation flow control mechanism in part according to the flow rate of the exhaust gas.

18. The method of claim 13, wherein the first and second sensors include probe electrodes made of 304 type stainless steel.

19. The method of claim 13,

wherein if the flow of particulate matter is sensed to be from the input to the output of the flow control mechanism, then the flow control mechanism may allow the flow to continue;

and

if the flow of particulate matter is sensed to be from the output to the input of the flow control mechanism, then the flow control mechanism may stop the flow.