发明名称 |
O2-sensor fault diagnosis method and apparatus |
摘要 |
An O2-sensor fault diagnosis method and apparatus for detecting a fault of an O2-sensor when a feedback control of a fuel supply to an engine is performed by making use of the output of an O2-sensor and detecting and identifying a fault of the O2-sensor even in the case where the feedback control is invalidated. A microcomputer (24) receives an output of an O2-sensor (19) for detecting concentration of oxygen contained in an exhaust gas of an internal combustion engine (1). An ECU (20) controls a quantity of fuel supplied to the internal combustion engine (1) through feedback control in dependence on an output signal of the O2-sensor (19). A first decision circuit is provided for deciding whether or not the O2-sensor (19) exhibits abnormality on the basis of the output signal state of the O2-sensor (19) by forcibly changing the amount of the fuel supplied to the engine during the feedback control, and a second decision circuit is provided for deciding abnormality of the O2-sensor (19) in accordance with an abnormality decision process which bears a stronger correlation to the abnormality than the decision performed by the first decision circuit. Fault detection of the O2-sensor is possible not only during the feedback control of the fuel supply but also in the state where the feedback control is not performed.
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申请公布号 |
US5685284(A) |
申请公布日期 |
1997.11.11 |
申请号 |
US19960615411 |
申请日期 |
1996.03.14 |
申请人 |
MITSUBISHI DENKI KABUSHIKI KAISHA |
发明人 |
NAKAMICHI, MASAKI |
分类号 |
F02B77/08;F02D41/14;(IPC1-7):F02D41/00 |
主分类号 |
F02B77/08 |
代理机构 |
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