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US 7,248,960 B2Granted
Air-fuel ratio sensor monitor, air-fuel ratio detector, and air-fuel ratio control
AssigneeDenso Corporation
InventorsNoriaki Ikemoto, Naoki Yoshiume, Yukihiro Yamashita
Life of this patent
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Abstract
An air-fuel ratio sensor monitor is provided which is designed to monitor reactive characteristics or response rates of an air-fuel ratio sensor when an air-fuel ratio of a mixture to an internal combustion engine is changing to a rich side and to a lean side. The monitored response rates are used in determining whether the sensor is failing or not, in determining the air-fuel ratio of the mixture accurately, or in air-fuel ratio control of the engine.
Claims49
An air-fuel ratio sensor failure detecting apparatus designed to detect a predetermined failure of an air-fuel ratio sensor installed in an exhaust line of an internal combustion engine, comprising:
- a correction factor determining circuit working to determine an air-fuel ratio correction factor to bring an air-fuel ratio, as detected through the air-fuel ratio sensor, into agreement with a target value;
- an air-fuel ratio change data determining circuit working to determine air-fuel ratio change data associated with changes in the detected air-fuel ratio to a rich and a lean side, respectively;
- an air-fuel ratio correction factor change data determining circuit working to determine air-fuel ratio correction factor change data associated with changes in the air-fuel ratio correction factor upon changes in the air-fuel ratio to the rich and lean sides, respectively;
- a response characteristic determining circuit working to determine response characteristics of the air-fuel ratio sensor upon the changes in the air-fuel ratio to the rich and lean sides, respectively, as functions of the air-fuel ratio change data and the air-fuel ratio correction factor change data;
- and
- a sensor failure detecting circuit working to detect the predetermined failure of the air-fuel ratio sensor based on the response characteristics, as determined by said response characteristic determining circuit.
3 more elements
A response characteristic detecting apparatus for an air-fuel ratio sensor installed in an exhaust line of an internal combustion engine, comprising:
- a correction factor determining circuit working to determine an air fuel ratio correction factor to bring an air-fuel ratio of a mixture to the engine, as detected through the air-fuel ratio sensor, into agreement with a target value;
- an air-fuel ratio change data determining circuit working to determine air-fuel ratio change data associated with changes in the detected air-fuel ratio to a rich and a lean side, respectively;
- an air-fuel ratio correction factor change data determining circuit working to determine air-fuel ratio correction factor change data associated with changes in the air-fuel ratio correction factor upon changes in the air-fuel ratio to the rich and lean sides, respectively;
- a response characteristic determining circuit working to determine response characteristics of the air-fuel ratio sensor upon the changes in the air-fuel ratio to the rich and lean sides, respectively, based on the air-fuel ratio change data and the air-fuel ratio correction factor change data;
- and
- a data determination permission circuit which works to selectively permit the air-fuel ratio change data and the air-fuel ratio correction factor change data to be determined based on behavior of the changes in the air-fuel ratio correction factor.
3 more elements
An air-fuel ratio detecting apparatus for an internal combustion engine comprising:
- an air-fuel ratio sensor installed in an exhaust line of an internal combustion engine to produce an output that is a function of an air-fuel ratio of a mixture to the engine:
- a correction factor determining circuit working to determine an air-fuel ratio correction factor to bring the air-fuel ratio, as detected through said air-fuel ratio sensor, into agreement with a target value;
- an air-fuel ratio change data determining circuit working to determine air-fuel ratio change data associated with changes in the detected air-fuel ratio to a rich and a lean side, respectively;
- an air-fuel ratio correction factor change data determining circuit working to determine air-fuel ratio correction factor change data associated with changes in the air-fuel ratio correction factor upon changes in the air-fuel ratio to the rich and lean sides, respectively;
- a response characteristic determining circuit working to determine response characteristics of said air-fuel ratio sensor upon the changes in the air-fuel ratio to the rich and lean sides, respectively, as functions of the air-fuel ratio change data and the air-fuel ratio correction factor change data;
- and
- an air-fuel ratio correcting circuit working to correct the detected air-fuel ratio using the response characteristics determined by said response characteristic determining circuit.
4 more elements
An air-fuel ratio detecting apparatus for an internal combustion engine comprising:
- an air-fuel ratio sensor installed in an exhaust line of an 5 internal combustion engine to produce an output that is a function of an air-fuel ratio of a mixture to the engine:
- an air-fuel ratio change data determining circuit working to determine air-fuel ratio change data associated with changes in the detected air-fuel ratio to a rich and a lean side, respectively;
- and
- an air-fuel ratio correcting circuit working to correct the detected air-fuel ratio based on the air-fuel ratio change data associated with the changes in the detected air-fuel ratio to the rich and lean sides.
1 more element
An air-fuel ratio controlling apparatus comprising:
- an air-fuel ratio sensor installed in an exhaust line of an internal combustion engine to produce an output that is a function of an air-fuel ratio of a mixture to the engine:
- a correction factor determining circuit working to determine an air-fuel ratio correction factor to bring an air-fuel ratio, as detected through the air-fuel ratio sensor, into agreement with a target air-fuel ratio value;
- an air-fuel ratio change data determining circuit working to determine air-fuel ratio change data associated with changes in the detected air-fuel ratio to a rich and a lean side, respectively;
- an air-fuel ratio correction factor change data determining circuit working to determine air-fuel ratio correction factor change data associated with changes in the air-fuel ratio correction factor upon changes in the air-fuel ratio to the rich and lean sides, respectively;
- a response characteristic determining circuit working to determine response characteristics of the air-fuel ratio sensor upon the changes in the air-fuel ratio to the rich and lean sides, respectively, as functions of the air-fuel ratio change data and the air-fuel ratio correction factor change data;
- and
- a control parameter correcting circuit working to correct a control parameter using the response characteristics of the air-fuel ratio sensor, the control parameter being used in controlling the air-fuel ratio of the mixture to the engine.
4 more elements
Dependencies are inferred from the claim text.