# US 8,769,936 B2 · Method for monitoring a regulated emission concentration in the exhaust gas of an internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,769,936 B2 - Document ID: US8769936B2 - Status: Granted - Kind: B2 - Application number: 13/276,020 - Filed: 2011-10-18 - Published: 2012-05-03 - Granted: 2014-07-08 - Earliest claimed: 2010-11-03 - Assignees: Ford Global Technologies, LLC - Applicants: Simon Petrovic; Yasser Mohamed sayed Yacoub - Inventors: Simon Petrovic; Yasser Mohamed sayed Yacoub - Web page: https://patentgrep.com/patent/US8769936B2 ## CPC - F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)} - F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus - F02D 41/0047: {Controlling exhaust gas recirculation [EGR] (temperature control with cooler in recirculation circuit F02M26/33)} - F02M 26/05: High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor - F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts} - F01N 2550/02: Catalytic activity of catalytic converters - F01N 2560/025: for measuring or detecting O2, e.g. lambda sensors - F02B 2039/168: {the rotational speed of pump or exhaust drive being limited} - F02D 41/1454: {the characteristics being an oxygen content or concentration or the air-fuel ratio} - F02D 41/1462: {with determination means using an estimation} - F02D 2250/36: Control for minimising NOx emissions - Y02T 10/12: Improving ICE efficiencies - Y02T 10/40: Engine management systems - 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) - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method for monitoring a regulated emissions concentration C, in the exhaust gas of an internal combustion engine is provided. The method comprises directing the exhaust gas through an exhaust-gas turbocharger, directing at least a portion of the exhaust gas through an exhaust-gas recirculation system, measuring an air ratio λmeas in the exhaust gas with a lambda probe, measuring a rotational speed nT of the exhaust-gas turbocharger with a sensor, and determining the regulated emission concentration Ci based on the air ratio λmeas and the rotational speed nT. In this way, the emission concentration of the exhaust may be determined as a function of the rotational speed of the turbine. ## Claims ### Claim 1 A method for monitoring a regulated emission concentration (Ci) in the exhaust gas of an internal combustion engine, comprising: directing the exhaust gas through an exhaust-gas turbocharger; directing at least a portion of the exhaust gas through an exhaust-gas recirculation (EGR) system; measuring an air ratio (λmeas) in the exhaust gas with a lambda probe; measuring a rotational speed (nT) of the exhaust-gas turbocharger with a sensor; estimating the portion of the exhaust gas directed through the exhaust-gas recirculation system based on the rotational speed (nT) of the exhaust gas turbocharger; and determining the regulated emission concentration (Ci) based on the air ratio (λmeas) and the estimated portion of the exhaust gas. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the regulated emission concentration (Ci) is determined in steady-state operation of the internal combustion engine at a fixed operating point characterized by at least two operating parameters. ### Claim 3 (depends on 2) The method as claimed in claim 2, wherein the at least two operating parameters comprise the rotational speed (nT) and a load of the internal combustion engine. ### Claim 4 (depends on 2) The method as claimed in claim 2, wherein the at least two operating parameters comprise a rotational speed (n) and a torque (T) of the internal combustion engine. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the regulated emission concentration (Ci) is determined based on a regression model including coefficients dependent upon operating points. ### Claim 6 (depends on 5) The method as claimed in claim 5, wherein the coefficients are stored in at least one characteristic map, with each characteristic map being assigned to a particular operating point. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the regulated emission concentration (CNOx) of nitrogen oxides (NOx) is determined. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein functionality of an exhaust-gas aftertreatment system may be determined based on the regulated emission concentration. ### Claim 9 (depends on 8) The method as claimed in claim 8, wherein the exhaust-gas aftertreatment system is a storage catalytic converter. ### Claim 10 A method for determining NOx concentration in an exhaust stream of an engine, comprising: estimating an exhaust gas recirculation (EGR) amount based on a turbine rotational speed; estimating NOx concentration based on the estimated EGR amount and an upstream exhaust air-fuel ratio, and further based on current operating conditions; and adjusting an engine operating parameter responsive to the estimated NOx concentration. ### Claim 11 (depends on 10) The method of claim 10, wherein the estimated NOx concentration is further based on engine speed and load. ### Claim 12 (depends on 10) The method of claim 10, wherein the estimated NOx concentration is further based on one or more of ambient pressure, temperature, humidity, and flow delay of the exhaust stream. ### Claim 13 (depends on 10) The method of claim 10, further comprising: if engine speed and load remain constant over a predetermined period of time, then adjusting the engine operating parameter responsive to the estimated NOx concentration; and if engine speed and load vary by a threshold amount over the predetermined period of time, then not adjusting the operating parameter responsive to the estimated NOx concentration. ### Claim 14 (depends on 10) The method of claim 10, wherein adjusting the operating parameter responsive to the estimated NOx concentration further comprises adjusting a fuel injection amount into one or more cylinders of the engine. ### Claim 15 (depends on 10) The method of claim 10, wherein the estimated NOx concentration is a first NOx concentration, and further comprising adjusting an operating parameter responsive to a difference between the first NOx and concentration and a second NOx concentration, the second NOx concentration based on the estimated EGR amount and an air-fuel ratio downstream of an exhaust aftertreatment device. ### Claim 16 (depends on 10) The method of claim 10, wherein adjusting the operating parameter responsive to the estimated NOx concentration further comprises sending a notification to a vehicle operator to replace an exhaust aftertreatment device. ### Claim 17 A system comprising: an engine; a turbine arranged in an exhaust stream downstream of the engine; an exhaust gas recirculation (EGR) system upstream of the turbine to direct at least a portion of the exhaust stream back to the engine; and a controller having instructions executable to: estimate an amount of EGR directed to the engine based on a rotational speed of the turbine; and adjust an operating parameter responsive to an emissions concentration, the emissions concentration based on the amount of EGR and an upstream exhaust air-fuel ratio, and further based on current operating conditions. ### Claim 18 (depends on 17) The system of claim 17, wherein the rotational speed of the turbine is inversely proportional to the portion of the exhaust stream diverted through the exhaust gas recirculation system upstream of the turbine. ### Claim 19 (depends on 17) The system of claim 17, wherein the instructions are executable to determine an NOx concentration of the exhaust, and wherein the NOx concentration of the exhaust is inversely proportional to the portion of the exhaust stream diverted through the EGR upstream of the turbine. ### Claim 20 (depends on 17) The system of claim 17, wherein the instructions are further executable to determine a degradation state of an exhaust aftertreatment device arranged in the exhaust stream based on the emissions concentration, and a second emissions concentration downstream of the exhaust aftertreatment device.