# US 2004/0163380 A1 · Device, method, and program recording medium for control of air-fuel ratio of 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 2004/0163380 A1 - Document ID: US20040163380A1 - Status: Published application - Kind: A1 - Application number: 10/481,245 - Filed: 2003-12-18 - Published: 2004-08-26 - Earliest claimed: 2001-06-19 - Assignees: Honda Giken Kogyo Kabushiki Kaisha - Inventors: Yuji Yasui - Web page: https://patentgrep.com/patent/US20040163380A1 ## CPC - F02D 41/1455: {with sensor resistivity varying with oxygen concentration (F02D41/1456 takes precedence)} - F02D 41/1401: {characterised by the control or regulation method (F02D41/1473, F02D41/1477 take precedence)} - F01N 2430/06: by varying fuel-air ratio, e.g. by enriching fuel-air mixture - F02D 41/1441: {Plural sensors} - F02D 41/1456: {with sensor output signal being linear or quasi-linear with the concentration of oxygen} - F02D 2041/141: {using a feed-forward control element} - F02D 2041/1416: {Observer} - F02D 2041/1423: {Identification of model or controller parameters} - F02D 2041/1433: {using a model or simulation of the system} - 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) ## Abstract An apparatus for controlling the air-fuel ratio of an internal combustion engine to stably determine a highly reliable identified value of a parameter of a model of an exhaust system including a catalytic converter and to increase the purifying capability of the catalytic converter. An exhaust-side control unit 7a sequentially variably sets a dead time of an exhaust system E depending on the flow rate of an exhaust gas supplied to a catalytic converter 3, and sequentially identifies the value of a parameter of a model of the exhaust system E which has a dead time element of the set dead time. The exhaust-side control unit 7a sequentially calculates a target air-fuel ratio KCMD to converge the output of an O2 sensor 6 to a target value using the identified value of the parameter, and an engine-side control unit 7b manipulates the air-fuel ratio of the internal combustion engine 1 depending on the target air-fuel ratio KCMD. According to the algorithm of the process of identifying the parameter of the model of the exhaust system E, the value of a weighted parameter is variable set depending on the flow rate of the exhaust gas. ## Claims ### Claim 1 An apparatus for controlling the air-fuel ratio of an internal combustion engine having an exhaust gas sensor disposed downstream of a catalytic converter disposed in an exhaust passage of the internal combustion engine, for detecting the concentration of a particular component in an exhaust gas which has passed through the catalytic converter, identifying means for sequentially identifying the value of a predetermined parameter of a predetermined model of an exhaust system, which ranges from a position upstream of said catalytic converter to said exhaust gas sensor and including said catalytic converter, for expressing a behavior of the exhaust system which is regarded as a system for generating the output of said exhaust gas sensor via at least a dead time element from the air-fuel ratio of the exhaust gas which enters said catalytic converter, manipulated variable generating means for sequentially generating a manipulated variable to determine an air-fuel ratio of the exhaust gas which enters said catalytic converter using the identified value of the parameter of said model to converge the output of said exhaust gas sensor to a predetermined target value, and air-fuel ratio manipulating means for manipulating the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine depending on the manipulated variable, said apparatus comprising: flow rate data generating means for sequentially generating data representative of a flow rate of the exhaust gas flowing through the catalytic converter; and dead time setting means for variably setting a set dead time as the dead time of a dead time element of the model of said exhaust system depending on the value of the data generated by said flow rate data generating means, wherein said identifying means identifies the value of said parameter using the value of the set dead time set by said dead time setting means. ### Claim 2 (depends on 1) An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein said identifying means comprises means for identifying the value of said parameter according to an algorithm for minimizing an error between the output of said exhaust gas sensor in the model of said exhaust system and an actual output of said exhaust gas sensor, said apparatus further comprising: means for variably setting the value of a weighted parameter of said algorithm depending on the value of the data generated by said flow rate data generating means. ### Claim 3 An apparatus for controlling the air-fuel ratio of an internal combustion engine having an exhaust gas sensor disposed downstream of a catalytic converter disposed in an exhaust passage of the internal combustion engine, for detecting the concentration of a particular component in an exhaust gas which has passed through the catalytic converter, identifying means for sequentially identifying the value of a predetermined parameter of a predetermined model of an exhaust system, which ranges from a position upstream of said catalytic converter to said exhaust gas sensor and including said catalytic converter, for expressing a behavior of the exhaust system which is regarded as a system for generating the output of said exhaust gas sensor from the air-fuel ratio of the exhaust gas which enters said catalytic converter, manipulated variable generating means for sequentially generating a manipulated variable to determine an air-fuel ratio of the exhaust gas which enters said catalytic converter using the identified value of the parameter of said model to converge the output of said exhaust gas sensor to a predetermined target value, and air-fuel ratio manipulating means for manipulating the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine depending on the manipulated variable, wherein: said identifying means comprises means for identifying the value of said parameter according to an algorithm for minimizing an error between the output of said exhaust gas sensor in the model of said exhaust system and an actual output of said exhaust gas sensor; wherein said apparatus further comprising: flow rate data generating means for sequentially generating data representative of a flow rate of the exhaust gas flowing through the catalytic converter; and means for variably setting the value of a weighted parameter of the algorithm of said identifying means depending on the value of the data generated by said flow rate data generating means. ### Claim 4 (depends on 1, 2, 3) An apparatus for controlling the air-fuel ratio of an internal combustion engine according to any one of claim 1 through 3, wherein identifying means determines the identified value of the parameter of the model of said exhaust system by limiting the identified value to a value within a predetermined range depending on the value of the data generated by said flow rate data generating means. ### Claim 5 A method of controlling the air-fuel ratio of an internal combustion engine, comprising the steps of sequentially identifying the value of a predetermined parameter of a predetermined model of an exhaust system, which ranges from a position upstream of a catalytic converter disposed in an exhaust passage of the internal combustion engine to an exhaust gas sensor disposed downstream of the catalytic converter for detecting the concentration of a particular component in an exhaust gas, and includes said catalytic converter, for expressing a behavior of the exhaust system which is regarded as a system for generating the output of said exhaust gas sensor via at least a dead time element from the air-fuel ratio of the exhaust gas which enters said catalytic converter, and sequentially generating a manipulated variable to determine an air-fuel ratio of the exhaust gas which enters said catalytic converter using the identified value of the parameter of said model in order to converge the output of said exhaust gas sensor to a predetermined target value, said internal combustion engine having air-fuel ratio manipulating means for manipulating the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine depending on the manipulated variable, said method comprising the steps of: sequentially generating data representative of a flow rate of the exhaust gas flowing through the catalytic converter, and sequentially setting a set dead time as the dead time of a dead time element of the model of said exhaust system depending on the value of the data representative of the flow rate of the exhaust gas, wherein said step of identifying the parameter of the model of said exhaust system identifies the value of said parameter using the value of said set dead time. ### Claim 6 (depends on 5) A method of controlling the air-fuel ratio of an internal combustion engine according to claim 5, wherein said step of identifying the parameter of the model of said exhaust system identifies the value of said parameter according to an algorithm for minimizing an error between the output of said exhaust gas sensor in the model of said exhaust system and an actual output of said exhaust gas sensor, and variably sets the value of a weighted parameter of said algorithm depending on the value of the data generated by said flow rate data generating means. ### Claim 7 A method of controlling the air-fuel ratio of an internal combustion engine, comprising the steps of sequentially identifying the value of a predetermined parameter of a predetermined model of an exhaust system, which ranges from a position upstream of a catalytic converter disposed in an exhaust passage of the internal combustion engine to an exhaust gas sensor disposed downstream of the catalytic converter for detecting the concentration of a particular component in an exhaust gas, and includes said catalytic converter, for expressing a behavior of the exhaust system which is regarded as a system for generating the output of said exhaust gas sensor from the air-fuel ratio of the exhaust gas which enters said catalytic converter, and sequentially generating a manipulated variable to determine an air-fuel ratio of the exhaust gas which enters said catalytic converter using the identified value of the parameter of said model in order to converge the output of said exhaust gas sensor to a predetermined target value, wherein the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine is manipulated depending on the manipulated variable, wherein: said step of identifying the parameter of the model of said exhaust system comprises the step of identifying the value of said parameter according to an algorithm for minimizing an error between the output of said exhaust gas sensor in the model of said exhaust system and an actual output of said exhaust gas sensor; said method further comprising the steps of: sequentially generating data representative of a flow rate of the exhaust gas flowing through the catalytic converter, and variably setting the value of a weighted parameter of said algorithm for identifying the parameter of said model depending on the value of the data representative of the flow rate of the exhaust gas. ### Claim 8 (depends on 5, 6, 7) A method of controlling the air-fuel ratio of an internal combustion engine according to any one of claims 5 through 7, wherein said step of identifying the parameter of the model of said exhaust system determines the identified value of the parameter of the model of said exhaust system by limiting the identified value to a value within a predetermined range depending on the value of the data representative of the flow rate of the exhaust gas. ### Claim 9 A recording medium readable by a computer and storing an air-fuel ratio control program for enabling said computer to perform a process of sequentially identifying the value of a predetermined parameter of a predetermined model of an exhaust system, which ranges from a position upstream of a catalytic converter disposed in an exhaust passage of the internal combustion engine to an exhaust gas sensor disposed downstream of the catalytic converter for detecting the concentration of a particular component in an exhaust gas, and includes said catalytic converter, for expressing a behavior of the exhaust system which is regarded as a system for generating the output of said exhaust gas sensor via at least a dead time element from the air-fuel ratio of the exhaust gas which enters said catalytic converter, a process of sequentially generating a manipulated variable to determine an air-fuel ratio of the exhaust gas which enters said catalytic converter using the identified value of the parameter of said model in order to converge the output of said exhaust gas sensor to a predetermined target value, and a process of manipulating the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine depending on the manipulated variable, wherein said program comprising: said air-fuel ratio control program includes a program for enabling the computer to perform a process of sequentially generating data representative of a flow rate of the exhaust gas flowing through the catalytic converter, and sequentially setting a value of said set dead time as the dead time of a dead time element of the model of said exhaust system depending on the value of the data representative of the flow rate of the exhaust gas, and said program for enabling the computer to identify the parameter of the model of said exhaust system identifies the parameter using the value of said set dead time. ### Claim 10 (depends on 9) A recording medium storing an air-fuel ratio control program for an internal combustion engine according to claim 9, wherein the program of said air-fuel ratio control program for enabling the computer to perform the process of identifying the value of the parameter of the model of said exhaust system identifies the value of said parameter according to an algorithm for minimizing an error between the output of said exhaust gas sensor in the model of said exhaust system and an actual output of said exhaust gas sensor, and variably sets the value of a weighted parameter of said algorithm depending on the value of the data representative of the flow rate of said exhaust gas. ### Claim 11 A recording medium readable by a computer and storing an air-fuel ratio control program for enabling said computer to perform a process of sequentially identifying the value of a predetermined parameter of a predetermined model of an exhaust system, which ranges from a position upstream of a catalytic converter disposed in an exhaust passage of the internal combustion engine to an exhaust gas sensor disposed downstream of the catalytic converter for detecting the concentration of a particular component in an exhaust gas, and includes said catalytic converter, for expressing a behavior of the exhaust system which is regarded as a system for generating the output of said exhaust gas sensor from the air-fuel ratio of the exhaust gas which enters said catalytic converter, a process of sequentially generating a manipulated variable to determine an air-fuel ratio of the exhaust gas which enters said catalytic converter using the identified value of the parameter of said model in order to converge the output of said exhaust gas sensor to a predetermined target value, and a process of manipulating the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine depending on the manipulated variable, wherein: the program of said air-fuel ratio control program for enabling the computer to perform the process of identifying the value of the parameter of the model of said exhaust system identifies the value of said parameter according to an algorithm for minimizing an error between the output of said exhaust gas sensor in the model of said exhaust system and an actual output of said exhaust gas sensor; and said air-fuel ratio control program includes a program for enabling the computer to perform a process of sequentially generating-data representative of a flow rate of the exhaust gas flowing through the catalytic converter, and a process of variably setting the value of a weighted parameter of said algorithm for identifying the parameter of said model depending on the value of the data representative of the flow rate of the exhaust gas. ### Claim 12 (depends on 9, 10, 11) A recording medium storing an air-fuel ratio control program for an internal combustion engine according to any one of claims 9 through 11, wherein the program of said air-fuel ratio control program for enabling the computer to perform the process of identifying the value of the parameter of the model of said exhaust system determines the identified value of the parameter of the model of said exhaust system by limiting the identified value to a value within a predetermined range depending on the value of the data representative of the flow rate of the exhaust gas.