Particulate matter sensor with engineered particle size cut-point

• US 10,641,154 B2
• Filed: 08/27/2015
• Issued: 05/05/2020
• Est. Priority Date: 08/27/2015
• Status: Active Grant

• Current Assignee: Cummins Emission Solutions Inc. (Cummins Incorporated)
• Original Assignee: Cummins Emission Solutions Inc. (Cummins Incorporated)
• Inventors: Cremeens, Christopher M., Yezerets, Aleksey, Prattipati, Reshma, Robinson, Michael A.
• Primary Examiner(s): Matthias, Jonathan R
• Application Number:
  US15/755,292
• Publication Number:
  US 20180245499A1
• Time in Patent Office: 1,713 Days
• CPC Class Codes: B01D 2279/30 for treatment of exhaust gases from IC Engines
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/44 controlling filtration
• CPC Class Codes: B01D 46/442 by measuring the concentration of particles
• CPC Class Codes: B01D 46/446 by pressure measuring
• 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 2550/00 Monitoring or diagnosing the deterioration of exhaust systems
• CPC Class Codes: F01N 2550/04 Filtering activity of particulate filters
• CPC Class Codes: F01N 2560/05 the means being a particulate sensor
• CPC Class Codes: F01N 3/021 by means of filters
• CPC Class Codes: G01N 1/2252 in a vehicle exhaust
• CPC Class Codes: G01N 15/0255 with mechanical, e.g. inertial, classification, and investigation of sorted collections with centrifuges G01N15/042
• CPC Class Codes: G01N 15/0606 by collecting particles on a support
• 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 15/0826 and measuring fluid flow rate, i.e. permeation rate or pressure change
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: G01N 2015/0261 using impactors
• CPC Class Codes: G01N 2015/084 Testing filters
• CPC Class Codes: G07C 5/0825 using optical means
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

Abstract

An aftertreatment system comprises a particulate filter configured to filter PM possessing a predetermined, least effective size range included in an exhaust gas flowing through the aftertreatment system. A PM sensor assembly is positioned downstream of the particulate filter and includes a housing having an inlet, an outlet, a sidewall and defines an internal volume. A PM sensor is positioned within the internal volume. The housing is configured to redirect a flow of exhaust gas entering the PM sensor assembly around the PM sensor so that small particles included in the exhaust gas flow having a first size within or smaller than the predetermined size range are directed around the particulate matter sensor. Large particles having a second size larger than the predetermined size range impact the PM sensor. A controller is communicatively coupled to the PM sensor.

Claims

1. An aftertreatment system, comprising:

a particulate filter configured to filter particulate matter possessing a predetermined size range included in an exhaust gas flowing through the aftertreatment system;

a particulate matter sensor assembly positioned downstream of the particulate filter, the particulate matter sensor assembly including;

a housing having a single inlet, a single outlet and a sidewall, the housing defining an internal volume, and

a particulate matter sensor positioned within the internal volume, the particulate matter sensor having a first flat surface facing the inlet of the housing, the first flat surface being inclined at an angle in a range of 75 degrees to 105 degrees with respect to a longitudinal axis of the particulate matter sensor assembly, and having at least one of a resistance sensor, a conductance sensor, and/or a capacitance sensor disposed thereon; and

a controller communicatively coupled to the particular matter sensor,

wherein the particulate matter sensor assembly is positioned within a flow path of the exhaust gas so that a portion of the exhaust gas enters the internal volume of the housing via the single inlet, wherein the housing is configured to redirect the flow of the portion of the exhaust gas around the particulate matter sensor such that small particles included in the portion of the exhaust gas flow having a first size within or smaller than the predetermined size range are directed around the particulate matter sensor, and large particles having a second size larger than the predetermined size range impact the particulate matter sensor.

2. The aftertreatment system of claim 1, wherein the predetermined size range is between 100 nm to 300 nm.

3. The aftertreatment system of claim 1, wherein the single inlet has a first cross-section and the single outlet has a second cross-section larger than the first cross-section.

4. The aftertreatment system of claim 1, wherein the sidewall of the housing is arcuate.

5. The aftertreatment system of claim 1, wherein a sensing portion of the particulate matter sensor is oriented orthogonally to a longitudinal axis of the particulate matter sensor assembly.

6. The aftertreatment system of claim 1, wherein the controller is configured to:

interpret a first electrical parameter value of the particulate matter sensor;

after a predetermined time has passed, interpret a second electrical parameter value of the particulate matter sensor;

if a difference between the second electrical parameter value and the first electrical parameter value is greater than a predetermined threshold, determine that the particulate filter has failed; and

indicate the failure of the particulate filter to a user.

7. The aftertreatment system of claim 6, wherein the first electrical parameter value is a baseline electrical parameter of the particulate matter sensor, and wherein the second electrical parameter value occurs as a result of impact and accumulation of the large particles on the particulate matter sensor, the accumulation changing the first electrical parameter value to the second electrical parameter value.

8. The aftertreatment system of claim 7, wherein the first electrical parameter value and the second electrical parameter value include at least one of a resistance, conductance and capacitance.

9. The aftertreatment system of claim 8, wherein the particulate matter sensor includes interdigitated electrodes.

10. The aftertreatment system of claim 7, further comprising:

a differential pressure sensor positioned across the particulate filter,

wherein the controller is communicatively coupled to the differential pressure sensor, the controller further configured to interpret a pressure output value from the differential pressure sensor, the pressure output value indicative of a filtering efficiency of the particulate filter.

11. A particulate matter sensor assembly for use in an aftertreatment system, comprising:

a housing having a single inlet, a single outlet and a sidewall, the housing defining an internal volume; and

a particulate matter sensor positioned within the internal volume, the particulate matter sensor having a first flat surface facing the inlet of the housing, the first flat surface being inclined at an angle in a range of 75 degrees to 105 degrees with respect to a longitudinal axis of the particulate matter sensor assembly, and having at least one of a resistance sensor, a conductance sensor, and/or a capacitance sensor disposed thereon,

wherein the housing is configured to redirect an exhaust gas flow entering through the single inlet and flowing around the particulate matter sensor such that that small particles included in the exhaust gas flow having a first size within or smaller than a predetermined size range are directed around the particulate matter sensor, and large particles having a second size larger than the predetermined size range impact the particulate matter sensor.

12. The particulate matter sensor assembly of claim 11, wherein the predetermined size range is between 100 nm to 300 nm.

13. The particulate matter sensor assembly of claim 11, wherein the single inlet has a first cross-section, and the single outlet has a second cross-section larger than the first cross-section.

14. The particulate matter sensor assembly of claim 11, wherein the sidewall of the housing is arcuate.

15. The particulate matter sensor assembly of claim 11, wherein a sensing portion of the particulate matter sensor is positioned orthogonal to a longitudinal axis of the particulate matter sensor assembly.

16. The particulate matter sensor assembly of claim 11, wherein the particulate matter sensor includes an accumulating-type sensor.

17. The particulate matter sensor assembly system of claim 16, wherein the particulate matter sensor includes interdigitated electrodes.

18. A method for determining a failure of a particulate filter configured to filter particulate matter possessing a predetermined size range, the particulate filter included in an aftertreatment system having a particulate matter sensor assembly positioned downstream of the particulate filter, the particulate matter sensor assembly comprising a housing having an inlet, an outlet and a sidewall, a particulate matter sensor positioned within an internal volume defined by the housing, the particulate matter sensor having a first flat surface facing the inlet of the housing, the first flat surface being inclined at an angle in a range of 75 degrees to 105 degrees with respect to a longitudinal axis of the particulate matter sensor assembly, and having at least one of a resistance sensor, a conductance sensor, and/or a capacitance sensor disposed thereon, the method comprising:

flowing an exhaust gas through the aftertreatment system, a portion of the exhaust gas flowing into the housing via the single inlet after flowing through the particulate filter, the housing configured to redirect the flow of the portion of the exhaust gas flow around the particulate matter sensor such that small particles included in the portion of the exhaust gas flow having a first size within or smaller than the predetermined size range are directed around the particulate matter sensor, and large particles having a second size larger than the predetermined size range impact the particulate matter sensor;

interpreting a first electrical parameter value of the particulate matter sensor;

allowing the exhaust gas to flow through the particulate matter sensor assembly for a predetermined time, the predetermined time enabling the large particles to accumulate on the particulate matter sensor;

interpreting a second electrical parameter value of the particulate matter sensor;

determining if a difference between the second electrical parameter value and the first electrical parameter value is greater than a predetermined threshold;

if the difference is greater than the predetermined threshold, determining a failure of the particulate filter; and

indicating the failure of the catalyst to a user.

19. The method of claim 18, wherein the first electrical parameter value is a baseline electrical parameter of the particulate matter sensor, and wherein the second electrical parameter value occurs as a result of impact and accumulation of the large particles on the particulate matter sensor, the accumulation changing the first electrical parameter value to the second electrical parameter value.

20. The method of claim 19, wherein the first electrical parameter value and the second electrical parameter value include at least one of a resistance, a conductance and a capacitance.

21. The method of claim 18, wherein the indicating comprises at least one of generating a fault code and lighting a malfunction indicator lamp.

22. The method of claim 18, wherein a sensing portion of the particulate matter sensor is positioned orthogonal to longitudinal axis of the particulate matter sensor assembly.

23. An aftertreatment system, comprising:

a particulate filter configured to filter particulate matter possessing a predetermined size range included in an exhaust gas flowing through the aftertreatment system;

a particulate matter sensor assembly positioned downstream of the particulate filter, the particulate matter sensor assembly including;

a housing having an inlet, an outlet and a sidewall, the housing defining an internal volume, and

a particulate matter sensor positioned within the internal volume, the particulate matter sensor having a first flat surface facing the inlet of the housing, the first flat surface being inclined at an angle in a range of 75 degrees to 105 degrees with respect to a longitudinal axis of the particulate matter sensor assembly, and having at least one of a resistance sensor, a conductance sensor, and/or a capacitance sensor disposed thereon; and

a controller communicatively coupled to the particular matter sensor, the controller configured to;

interpret a first electrical parameter value of the particulate matter sensor;

after a predetermined time has passed, interpret a second electrical parameter value of the particulate matter sensor;

if a difference between the second electrical parameter value and the first electrical parameter value is greater than a predetermined threshold, determine that the particulate filter has failed; and

indicate the failure of the particulate filter to a user,

wherein the particulate matter sensor assembly is positioned within a flow path of the exhaust gas so that a portion of the exhaust gas enters the internal volume of the housing via the inlet, wherein the housing is configured to redirect the flow of the portion of the exhaust gas around the particulate matter sensor such that small particles included in the portion of the exhaust gas flow having a first size within or smaller than the predetermined size range are directed around the particulate matter sensor, and large particles having a second size larger than the predetermined size range impact the particulate matter sensor.