# US 2014/0150406 A1 · Methods and systems for a particulate matter sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0150406 A1 - Document ID: US20140150406A1 - Status: Published application - Kind: A1 - Application number: 13/706,048 - Filed: 2012-12-05 - Published: 2014-06-05 - Earliest claimed: 2012-12-05 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: William Russell Goodwin - Web page: https://patentgrep.com/patent/US20140150406A1 ## CPC - F01N 11/007: {the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus} - F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus - F02D 41/1466: {the characteristics being a soot concentration or content} - F02D 41/1494: {Control of sensor heater} - F02D 41/222: {relating to the failure of sensors or parameter detection devices} - F01N 2550/04: Filtering activity of particulate filters - F01N 2900/1411: Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate - 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 Various systems and methods are described for a particulate matter sensor coupled to an exhaust system of an engine. One example method comprises, during a measurement mode, generating a particulate flow rate based on the sensor and adjusting one or more engine operating parameters based on the flow rate. The method further includes, during a reduced contamination mode, heating the sensor to repel particulate from the sensor, and not adjusting the one or more operating parameters based on the sensor. ## Claims ### Claim 1 A method for a particulate matter sensor, comprising: generating an indication of particulate flow rate through a particulate filter based on particulate accumulation on a sensing element of the sensor, and diagnosing the sensor based on the flow rate; and after diagnosing of the sensor is completed, heating a sensing element of the sensor to repel particulate from the sensing element. ### Claim 2 (depends on 1) The method of claim 1, wherein generating the indication of particulate flow rate includes operating the sensor in a measurement mode. ### Claim 3 (depends on 2) The method of claim 2, further comprising adjusting one or more engine operating parameters based on the flow rate during the measurement mode. ### Claim 4 (depends on 3) The method of claim 3, wherein the one or more engine operating parameters includes engine fueling and air fuel ratio. ### Claim 5 (depends on 2) The method of claim 2, wherein the sensor is operated in the measurement mode only once per drive cycle of an engine to which the sensor is coupled in an exhaust passage thereof. ### Claim 6 (depends on 1) The method of claim 1, wherein heating the sensing element includes heating the sensor to a temperature greater than an exhaust gas temperature, and maintaining it greater than the exhaust gas temperature even as the exhaust gas temperature fluctuates with engine operating conditions, but less than a temperature at which soot burns. ### Claim 7 (depends on 1) The method of claim 1, wherein heating the sensing element to repel particulate from the sensing element includes operating the sensor in a reduced contamination mode. ### Claim 8 (depends on 7) The method of claim 7, further comprising not adjusting one or more engine operating parameters based on the sensor during the reduced contamination mode. ### Claim 9 (depends on 1) The method of claim 1, wherein heating the sensing element of the sensor includes initiating operation of a sensor heater. ### Claim 10 (depends on 1) The method of claim 1, further comprising indicating degradation of the particulate filter based on the flow rate generated by the sensor. ### Claim 11 A method, comprising: during a drive cycle of an engine: during a measurement mode, generating a particulate flow rate through a particulate filter based on particulate accumulation on a sensing element of a particulate matter sensor, and adjusting one or more engine operating parameters based on the sensor; and during a reduced contamination mode, increasing a sensor temperature to a temperature greater than an exhaust gas temperature to repel particulate from the sensing element, and not adjusting the engine operating parameters based on the sensor. ### Claim 12 (depends on 11) The method of claim 11, further comprising operating the sensor in the measurement mode once during the drive cycle. ### Claim 13 (depends on 11) The method of claim 11, wherein the engine operating parameters include engine fueling and air fuel ratio. ### Claim 14 (depends on 11) The method of claim 11, wherein increasing the sensor temperature includes increasing the sensor temperature to a temperature less than a temperature at which soot burns. ### Claim 15 (depends on 11) The method of claim 11, wherein a change in the sensor temperature due to the increase is based on one or more sensor operating parameters. ### Claim 16 (depends on 11) The method of claim 11, further comprising, during the measurement mode, indicating degradation of the sensor when the particulate flow rate is greater than a threshold flow rate. ### Claim 17 A system, comprising: an engine with an exhaust system; a particulate matter sensor disposed downstream of a particulate filter in the exhaust system, the particulate matter sensor including a heater, and a sensing element exposed to an exhaust gas stream; a control system in communication with the particulate matter sensor, the control system including non-transitory instructions to, during a measurement mode, generate a particulate flow rate through the particulate filter based on the particulate matter sensor, and adjust one or more engine operating parameters based on the particulate flow rate; and, during a reduced contamination mode, initiate operation of the heater to increase a sensor temperature to repel particulate matter from the sensing element, and not adjust the engine operating parameters based on the sensor. ### Claim 18 (depends on 17) The system of claim 17, wherein the control system further includes instructions to indicate degradation of the particulate filter based on the particulate flow rate. ### Claim 19 (depends on 17) The system of claim 17, further comprising an exhaust temperature sensor configured to output an exhaust gas temperature. ### Claim 20 (depends on 19) The system of claim 19, wherein the control system further includes instructions to increase the sensor temperature to a temperature higher than the exhaust gas temperature, but less than a temperature at which soot burns.