Diagnostic system of an air-fuel ratio control device
Internal combustion engine with device for warning of malfunction in an air-fuel ratio control system
Method of detecting abnormality in fuel supply systems of internal combustion engines
Fuel delivery control apparatus for engine operable on gasoline/alcohol fuel blend
Vehicle engine fuel system diagnostics
Learning-correcting method and apparatus and self-diagnosis method and apparatus in fuel supply control system of internal combustion engine
Apparatus for controlling the respective cylinders in the fuel supply system of an internal combustion engine Patent #: 5131372
ApplicationNo. 842425 filed on 02/27/1992
US Classes:123/690With fail-safe, backup, or malfunction means
ExaminersPrimary: Nelli, Raymond A.
Attorney, Agent or Firm
Foreign Patent References
International ClassF02M 051/00
Foreign Application Priority Data1991-03-08 JP
AbstractIn an apparatus for diagnosing an abnormality in a fuel injection system in which an injection quantity is feedback-controlled by adjusting a first air-fuel ratio correction value so that an air-fuel ratio is equal to a target air-fuel ratio. The injection quantity is also adjusted by a second air-fuel ratio correction value. When the first air-fuel ratio correction value has reached a first upper limit value, the second air-fuel ratio correction value is set to a second upper limit value. When the first air-fuel ratio correction value has reached a second lower limit value, the second air-fuel ratio correction value is set to a second lower limit value. When the first air-fuel ratio correction value is outside of a predetermined range when a predetermined time has elapsed after the second air-fuel ratio correction value is set to either the second upper limit value or the second lower limit value, it is determined that a fault has occured in the fuel injection system.