METHOD AND ARRANGEMENT FOR MAINTAINING A DIESEL PARTICULATE FILTER IN A DIESEL ENGINE EXHAUST SYSTEM

• US 20100089041A1
• Filed: 05/01/2007
• Published: 04/15/2010
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: AB Volvo
• Original Assignee: MACK Trucks Incorporated (AB Volvo)
• Inventors: Tai, Chun, Svensson, Kenth I.
• Granted Patent: US 8,464,521 B2
• Time in Patent Office: Days
• US Class Current: 60/287
• CPC Class Codes: F01N 2560/06 the means being a temperature sensor
• CPC Class Codes: F01N 2560/08 the means being a pressure sensor
• CPC Class Codes: F01N 2900/1606 Particle filter loading or soot amount
• CPC Class Codes: F01N 3/027 using electric or magnetic heating means
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F02D 2041/1417 Kalman filter
• CPC Class Codes: F02D 2200/0812 Particle filter loading
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method and apparatus for maintaining a diesel particulate filter (DPF) is provided. A pressure drop across the DPF is measured and an initial estimate of soot loading in the DPF is provided to a recursive filter. Using the recursive filter, the initial estimate of soot loading is updated in view of the measured pressure drop to provide an updated estimate of soot loading in the DPF. Active regeneration of the DPF is triggered when an earliest one of at least one triggering condition occurs, the updated estimate of soot loading reaching a predetermined value being one of the at least one triggering condition.

Claims

1. A method for maintaining a DPF, comprising:

measuring a pressure drop across the DPF;

providing an initial estimate of soot loading in the DPF to a recursive filter;

using the recursive filter, updating the initial estimate of soot loading in view of the measured pressure drop to provide an updated estimate of soot loading in the DPF;

triggering active regeneration of the DPF when an earliest one of at least one triggering condition occurs, the updated estimate of soot loading reaching a predetermined value being one of the at least one triggering condition.

2. The method for maintaining a DPF as set forth in claim 1, wherein the recursive filter is a Kalman filter.

3. The method for maintaining a DPF as set forth in claim 1, comprising at least periodically measuring the pressure drop across the DPF, and at least periodically updating the updated estimate of soot loading in view of respective ones of the at least periodic pressure drop measurements to generate a plurality of updated estimates of soot loading and calculating a standard deviation of the plurality of updated estimates of soot loading, comprising triggering regeneration when the updated estimate of soot loading plus the standard deviation, or a function of the estimated error, of the plurality of updated estimates of soot loading exceeds a predetermined value.

4. The method for maintaining a DPF as set forth in claim 3, wherein the recursive filter is a Kalman filter.

5. The method for maintaining a DPF as set forth in claim 4, wherein a measurement noise covariance in the Kalman filter is a function of a non-uniformly distributed soot mass estimate.

6. The method for maintaining a DPF as set forth in claim 5, wherein the non-uniformly distributed soot mass estimate is a function of exhaust gas flow velocity in the DPF and soot reaction rate.

7. The method for maintaining a DPF as set forth in claim 1, comprising, after triggering active regeneration of the DPF, stopping active regeneration of the DPF when another earliest one of at least one stopping condition occurs, the updated estimate of soot loading reaching another predetermined value being one of the at least one stopping condition.

8. The method for maintaining a DPF as set forth in claim 7, wherein the recursive filter is a Kalman filter.

9. The method for maintaining a DPF as set forth in claim 8, wherein a measurement noise covariance in the Kalman filter is a function of a non-uniformly distributed soot mass estimate.

10. The method for maintaining a DPF as set forth in claim 9, wherein the non-uniformly distributed soot mass estimate is a function of exhaust gas flow velocity in the DPF and soot reaction rate.

11. The method for maintaining a DPF as set forth in claim 7, wherein another one of the at least one stopping condition comprises lapsing of a predetermined period of time.

12. The method for maintaining a DPF as set forth in claim 1, comprising calculating exhaust gas flow velocity through the DPF and adjusting the initial estimate for soot distribution as a function of the exhaust gas flow velocity.

13. A computer program stored on a computer-readable medium for performing the method of claim 1.

14. A method for estimating soot loading in a DPF, comprising:

measuring a pressure drop across the DPF;

providing an initial estimate of soot loading in the DPF to a recursive filter; and

using the recursive filter, updating the initial estimate of soot loading in view of the measured pressure drop to provide an updated estimate of soot loading in the DPF.

15. The method for estimating soot loading in a DPF as set forth in claim 14, wherein the filter is a Kalman filter.

16. The method for estimating soot loading in a DPF as set forth in claim 15, wherein a measurement noise covariance in the Kalman filter is a function of a non-uniformly distributed soot mass estimate.

17. The method for estimating soot loading in a DPF as set forth in claim 16, wherein the non-uniformly distributed soot mass estimate is a function of exhaust gas flow velocity in the DPF and soot reaction rate.

18. A computer program stored on a computer-readable medium for performing the method of claim 14.

19. A diesel engine system, comprising:

a diesel engine;

a DPF downstream of the engine;

a pressure sensor arrangement for measuring pressure drop across the DPF; and

a control system comprising a recursive filter arranged so that, upon provision of an estimate of soot loading in the DPF and a measurement by the pressure sensor arrangement of pressure drop across the DPF, an updated estimate of soot loading in the DPF is provided, and so that active regeneration of the DPF is triggered in response to at least one triggering condition, the at least one triggering condition including the updated estimate of soot loading.

20. The diesel engine system as set forth in claim 19, wherein the pressure sensor arrangement at least periodically measures the pressure drop across the DPF, and the control system is adapted to periodically update the updated estimate of soot loading in view of respective ones of the at least periodic pressure drop measurements to generate a plurality of updated estimates of soot loading and to periodically calculate a standard deviation of the plurality of updated estimates of soot loading, the control system being adapted to trigger regeneration when the updated estimate of soot loading plus the standard deviation, or a function of the estimated error, of the plurality of updated estimates of soot loading exceeds a predetermined value.

21. The diesel engine system as set forth in claim 19, wherein the recursive filter is a Kalman filter.

22. The diesel engine system as set forth in claim 21, wherein a measurement noise covariance in the Kalman filter is a function of a non-uniformly distributed soot mass estimate.

23. The diesel engine system as set forth in claim 22, wherein the non-uniformly distributed soot mass estimate is a function of exhaust gas flow velocity in the DPF and soot reaction rate.