Method for Determining the Charge State of a Particle Filter Installed in the Exhaust Gas Line of an Internal Combustion Engine and Device for Reducing the Particle Emissions of an Internal Combustion Engine

• US 20110036070A1
• Filed: 03/06/2009
• Published: 02/17/2011
• Est. Priority Date: 03/15/2008
• Status: Active Grant

• Current Assignee: HJS Emission Technology GmbH & Co. KG
• Original Assignee: HJS Fahrzeugtechnik GmbH & Co. KG
• Inventors: Schrewe, Klaus, Mandt, Rüdiger
• Granted Patent: US 8,152,912 B2
• Time in Patent Office: Days
• US Class Current: 60/273
• CPC Class Codes: F01N 2260/04 for regeneration or reactivation, e.g. of catalyst
• 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: F01N 2560/08 the means being a pressure sensor
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for determining the charge state of a particle filter installed in the exhaust gas line of an internal combustion engine comprises the following steps: determining the exhaust gas volumetric flow in the flow direction of the exhaust gas downstream of the particle filter (2), detecting the pressure present in the exhaust gas line (1) in the direction of flow of the exhaust gas prior to the particle filter (2), comparing the exhaust gas volumetric flow determined hinter the particle filter (2) with the detected pressure present upstream of the particle filter (2) and evaluating the results of the comparison with consideration to the exhaust gas back pressure of the uncharged particle filter (2) and the exhaust gas back pressure caused by the particle filter charge, said pressure being higher than the uncharged filter. Further described is a corresponding device for reducing the particle emissions of an internal combustion engine.

Claims

1-14. -14. (canceled)

15. A method for determining the soot charge state of a particle filter installed in the exhaust gas line of an internal combustion engine, in particular a diesel engine, comprising the following steps:

determining of a volumetric flow of a exhaust gas in the direction of flow of the exhaust gas downstream of the particle filter;

detecting the pressure prevailing upstream of the particle filter in the exhaust gas line in the direction of flow of the exhaust gas;

comparing the determined volumetric flow of the exhaust gas downstream of the particle filter in the direction of flow with the prevailing pressure detected upstream of the particle filter; and

evaluating the result of the comparison, taking into account the exhaust gas backpressure of the uncharged particle filter and the higher exhaust gas backpressure caused by the soot charge of the particle filter, compared to the uncharged filter.

16. The method of claim 15 wherein the determination of the volumetric flow of the exhaust gas in the direction of flow of the exhaust gas downstream of the particle filter and the detection of the prevailing pressure in the exhaust gas line in the direction of flow of the exhaust gas upstream of the particle filter is performed simultaneously or virtually simultaneously.

17. The method of claim 15, wherein to determine the volumetric flow of the exhaust gas in the direction of flow of the exhaust gas downstream of the particle filter and/or for detecting the prevailing pressure upstream of the particle filter, in each case several measurements are performed at a defined time interval and that the respective mean value is used for the downstream evaluation.

18. The method of claim 16, wherein to determine the volumetric flow of the exhaust gas in the direction of flow of the exhaust gas downstream of the particle filter and/or for detecting the prevailing pressure upstream of the particle filter, in each case several measurements are performed at a defined time interval and that the respective mean value is used for the downstream evaluation.

19. The method of claim 17, in that the weighted mean value of the measurements is used for the evaluation.

20. The method according to claim 15, wherein the determination of the volumetric flow downstream of the particle filter further comprises the steps of detecting a total pressure and detecting a static pressure, and wherein a dynamic pressure is determined from said results which is relevant for the determination of the volumetric flow.

21. The method of claim 15 wherein the results of the volumetric flow determination downstream of the particle filter and those of the pressure measurement upstream of the particle filter are corrected for temperature.

22. The method of claim 15 wherein during the determination of a sufficient soot charge of the particle filter a regeneration signal is generated.

23. The method of claim 22 wherein a regeneration process for regenerating the particle filter is initiated only if in addition to the respective regeneration signal for the necessary soot charge one or several soot regeneration conditions are met.

24. A device for reducing the particle emissions of an internal combustion engine, in particular a diesel engine, comprising:

a particle filter installed in the exhaust gas line of the internal combustion engine;

a device for determining the soot charge state of the particle filter, the device for determining the charge state having a pressure sensor arranged in the exhaust gas line in a direction of flow of the exhaust gas upstream of the particle filter for detecting the prevailing pressure in the exhaust gas line and a volumetric flow sensor arranged downstream of the particle filter in the direction of the flow of the exhaust gas; and

wherein two sensors for evaluating measured results are connected to control a unit.

25. The device of claim 24, wherein volumetric flow sensor comprises a measuring cone arranged in the exhaust gas line, a longitudinal axis of the measuring cone being parallel to a longitudinal axis of the exhaust gas line in this section;

the measuring cone arranged with a conical surface facing the direction of flow of the exhaust gas in the exhaust gas line, wherein one measuring point for measuring the dynamic pressure in the center of the cone is located opposite to the direction of flow of the exhaust gas, and one measuring point for measuring the static pressure is located in the no-flow zone of the measuring cone.

26. The device of claim 25, wherein the measuring points in both connected by means of a measuring channel with a pressure sensor arranged outside of the exhaust gas line.

27. The device of claim 26, wherein the measuring cone is held by a body forming the measuring channel(s) within the exhaust gas line.

28. The device of claim 27, wherein the measuring channels are arranged in a support body which holds the measuring cone in the exhaust gas line.

29. The device of claims 25, wherein the measuring cone further comprises an effective fluidic trailing edge on its largest diameter that determines the radial termination.