# US 8,464,521 B2 · Method and arrangement for maintaining a diesel particulate filter in a diesel engine exhaust system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,521 B2 - Document ID: US8464521B2 - Status: Granted - Kind: B2 - Application number: 12/597,886 - Filed: 2007-05-01 - Published: 2010-04-15 - Granted: 2013-06-18 - Earliest claimed: 2007-05-01 - Assignees: Mack Trucks, Inc. - Applicants: Chun Tai; Kenth I. Svensson - Inventors: Chun Tai; Kenth I. Svensson - Web page: https://patentgrep.com/patent/US8464521B2 ## CPC - F01N 9/002: {of filter regeneration} - F02D 41/029: {the exhaust gas treating apparatus being a particulate filter} - F01N 3/027: using electric or magnetic heating means - F01N 2560/06: the means being a temperature sensor - F01N 2560/08: the means being a pressure sensor - F01N 2900/1606: Particle filter loading or soot amount - F02D 2041/1417: {Kalman filter} - F02D 2200/0812: Particle filter loading - Y02T 10/40: Engine management systems - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## 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 ### Claim 1 A method for estimating soot loading in a DPF, comprising: measuring a pressure drop across the DPF; providing an estimate of soot mass loading in the DPF to a recursive filter, the estimate of soot mass loading comprising a first component determined as a function of the measured pressure drop across the DPF and assuming uniform soot mass distribution and a second, modeled non-uniform soot mass distribution component determined as a function of soot reaction rate and exhaust gas flow velocity in the DPF; and using the recursive filter, updating the estimate of soot mass loading in view of the measured pressure drop to provide an updated estimate of soot mass loading in the DPF; at least periodically measuring the pressure drop across the DPF, and at least periodically updating the updated estimate of soot mass loading in view of the at least periodic pressure drop measurements to generate a. plurality of updated estimates of soot mass loading and calculating a standard deviation of the plurality of updated estimates of soot mass loading; and triggering regeneration when the updated estimate of soot mass loading plus the standard deviation, or a function of the estimated error, of the plurality of updated estimates of soot mass loading exceeds a predetermined value. ### Claim 2 (depends on 1) The method for estimating soot loading in a DPF as set forth in claim 1, wherein the modeled non-uniform soot mass distribution is a function of exhaust gas flow velocity in the DPF and soot reaction rate. ### Claim 3 (depends on 1) The method for estimating soot loading in a DPF as set forth in claim 1, wherein the recursive filter is a Kalman filter. ### Claim 4 (depends on 3) The method for estimating soot loading in a DPF as set forth in claim 3, wherein a measurement noise covariance in the Kalman filter is a function of the modeled non-uniform soot mass distribution. ### Claim 5 (depends on 1) The method for estimating soot loading in a DPF as set forth in claim 1, comprising, after triggering regeneration of the DPF, stopping regeneration of the DPF when another earliest one of at least one stopping condition occurs, the updated estimate of soot mass loading reaching another predetermined value being one of the at least one stopping condition. ### Claim 6 (depends on 5) The method for estimating soot loading in a DPF as set forth in claim 5, wherein another one of the at least one stopping condition comprises lapsing of a predetermined period of time. ### Claim 7 (depends on 1) Anon-transitory computer-readable medium including a computer program for performing the method of claim 1. ### Claim 8 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 mass loading in the DPF and a measurement b the pressure sensor arrangement of pressure drop across the DPF, an updated estimate of soot mass 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 mass loading, the estimate of soot mass loading comprising a first component determined as a function of the measured pressure drop across the DPF and assuming uniform soot mass distribution and a second, modeled non-uniform soot mass distribution component determined as a function of soot reaction rate and exhaust gas flow velocity in the DPF, 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 mass loading in view of respective ones of the at least periodic pressure drop measurements to generate a plurality of updated estimates of soot mass loading and to periodically calculate a standard deviation of the plurality of updated estimates of soot mass loading, the control system being adapted to trigger regeneration when the updated estimate of soot mass loading plus the standard deviation, or a function of the estimated error, of the plurality of updated estimates of soot mass loading exceeds a predetermined value. ### Claim 9 (depends on 8) The diesel engine system as set forth in claim 8, wherein the recursive filter is a Kalman filter. ### Claim 10 (depends on 9) The diesel engine system as set forth in claim 9, wherein a measurement noise covariance in the Kalman filter is a function of the modeled non-uniform soot mass distribution.