Soot load estimation using dual differential pressure sensors

Patent metadata

Field	Value
Publication number	US-11035281-B2
Application number	US-201816975982-A
Country	US
Kind code	B2
Filing date	Mar 5, 2018
Priority date	Mar 5, 2018
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

An exhaust filtration system comprises a first pressure sensor and a second pressure sensor, each configured to measure pressure in the exhaust filtration system under low-flow conditions. The exhaust filtration system comprises a third pressure sensor and a fourth pressure sensor, each configured to measure pressure in the exhaust filtration system under high-flow conditions. A flow rate of exhaust gas flowing through the exhaust filtration system is periodically determined. When the flow rate is below a predetermined flow rate threshold, the first and second pressure sensors are used to measure pressure in the exhaust filtration system, and a soot load of the exhaust filtration system is estimated using the pressure measured by the first and second pressure sensors. When the flow rate is above the predetermined flow rate threshold, the third and fourth pressure sensors are used to measure pressure in the exhaust filtration system and a soot load of the exhaust filtration system is estimated using the pressure measured by the third and fourth pressure sensors.

First claim

What is claimed is:

1. A method for estimating soot load in an exhaust filtration system of an exhaust aftertreatment system that is configured to receive exhaust gas from an engine, the method comprising:
providing the exhaust filtration system comprising:
a first pressure sensor located at an inlet of the exhaust filtration system configured to measure a first pressure in the exhaust filtration system under low-flow conditions and a second pressure sensor located at an outlet of the exhaust filtration system configured to measure a second pressure in the exhaust filtration system under low-flow conditions;
a third pressure sensor located at the inlet of the exhaust filtration system configured to measure a third pressure in the exhaust filtration system under high-flow conditions and a fourth pressure sensor located at the outlet of the exhaust filtration system configured to measure a fourth pressure in the exhaust filtration system under high-flow conditions;

periodically determining a flow rate of exhaust gas flowing through the exhaust filtration system;
when the flow rate is below a predetermined flow rate threshold, using the first and second pressure sensors to measure the first and second pressures in the exhaust filtration system, respectively, and estimating a soot load of the exhaust filtration system using the first and second pressures measured by the first and second pressure sensors; and
when the flow rate is above the predetermined flow rate threshold, using the third and fourth pressure sensors to measure the third and fourth pressures in the exhaust filtration system, respectively, and estimating a soot load of the exhaust filtration system using the third and fourth pressures measured by the third and fourth pressure sensors.

2. The method of claim 1 , wherein the predetermined flow rate threshold is in a range of 0.05 to 1.5 m 3 /s.

3. The method of claim 1 , wherein:
when the flow rate is below the predetermined flow rate threshold, the soot load is estimated based on a difference between the first pressure measured by the first pressure sensor and the second pressure measured by the second pressure sensor; and
when the flow rate is above the predetermined flow rate threshold, the soot load is estimated based on a difference between the third pressure measured by the third pressure sensor and the fourth pressure measured by the fourth pressure sensor.

4. The method of claim 1 , further comprising comparing the estimated soot load to a predetermined soot load threshold.

5. The method of claim 4 , further comprising running an exhaust filter regeneration process when the estimated soot load is higher than the predetermined soot load threshold.

6. The method of claim 4 , wherein the predetermined soot load threshold is at least 4.5 g/L.

7. The method of claim 4 , wherein the predetermined soot load threshold is in a range of 4.5-6 g/L.

8. The method of claim 1 , wherein, in the step of periodically determining the flow rate, the flow rate is updated at a rate of at least 5 Hz.

9. The method of claim 1 , wherein the first and second pressure sensors are calibrated for use in measuring a first range of pressures, and the third and fourth pressure sensors are calibrated for use in measuring a second range of pressures, wherein at least a portion of the second range of pressures is greater than at least a portion of the first range of pressures.

10. The method of claim 1 , wherein the first and second pressure sensors are rated for use in measuring a first range of pressures, and the third and fourth pressure sensors are rated for use in measuring a second range of pressures, wherein at least a portion of the second range of pressures is greater than at least a portion of the first range of pressures.

11. An exhaust filtration system of an exhaust aftertreatment system that is configured to receive exhaust gas from an engine, the exhaust filtration system comprising:
a first pressure sensor located at an inlet of the exhaust filtration system configured to measure a first pressure in the exhaust filtration system under low-flow conditions and a second pressure sensor located at an outlet of the exhaust filtration system configured to measure a second pressure in the exhaust filtration system under low-flow conditions;
a third pressure sensor located at the inlet of the exhaust filtration system configured to measure a third pressure in the exhaust filtration system under high-flow conditions and a fourth pressure sensor located at the outlet of the exhaust filtration system configured to measure a fourth pressure in the exhaust filtration system under high-flow conditions; and
a controller configured to:
periodically determine a flow rate of exhaust gas flowing through the exhaust filtration system;
when the flow rate is below a predetermined flow rate threshold, activate the first and second pressure sensors to measure the first and second pressures in the exhaust filtration system, respectively, and estimate a soot load of the exhaust filtration system using the first and second pressures measured by the first and second pressure sensors; and
when the flow rate is above the predetermined flow rate threshold, activate the third and fourth pressure sensors to measure the third and fourth pressures in the exhaust filtration system, respectively, and estimate a soot load of the exhaust filtration system using the third and fourth pressures measured by the third and fourth pressure sensors.

12. The exhaust filtration system of claim 11 , wherein the predetermined flow rate threshold is in a range of 0.05 to 1.5 m 3 /s.

13. The exhaust filtration system of claim 11 , wherein the predetermined flow rate threshold is in a range of 0.1 to 1.4 m 3 /s.

14. The exhaust filtration system of claim 11 , wherein the predetermined flow rate threshold is in a range of 0.3 to 1.1 m 3 /s.

15. The exhaust filtration system of claim 11 , wherein the predetermined flow rate threshold is in a range of 0.5 to 0.9 m 3 /s.

16. The exhaust filtration system of claim 11 , wherein the controller is further configured to:
when the flow rate is below the predetermined flow rate threshold, estimate the soot load based on a difference between the first pressure measured by the first pressure sensor and the second pressure measured by the second pressure sensor; and
when the flow rate is above the predetermined flow rate threshold, estimate the soot load based on a difference between the third pressure measured by the third pressure sensor and the fourth pressure measured by the fourth pressure sensor.

17. The exhaust filtration system of claim 11 , wherein the controller is further configured to compare the estimated soot load to a predetermined soot load threshold.

18. The exhaust filtration system of claim 17 , wherein the controller is further configured to run an exhaust filter regeneration process when the estimated soot load is higher than the predetermined soot load threshold.

19. The exhaust filtration system of claim 17 , wherein the predetermined soot load threshold is at least 4.5 g/L.

20. The exhaust filtration system of claim 17 , wherein the predetermined soot load threshold is in a range of 4.5-6 g/L.

21. The exhaust filtration system of claim 11 , wherein, in the step of periodically determining the flow rate by the controller, the flow rate is updated at a rate of at least 5 Hz.

22. The exhaust filtration system of claim 11 , wherein the first and second pressure s

Assignees

• Cummins Emission Solutions Inc

Inventors

• Srinivasan Sriram

Classifications

• F01N2900/1606

  Particle filter loading or soot amount · CPC title

• F01N2900/1411

  Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate · CPC title

• F01N2560/14

  having more than one sensor of one kind · CPC title

• F01N2560/08

  the means being a pressure sensor · CPC title

• F01N9/002 Primary

  of filter regeneration · CPC title