Patent ID: 8074504
Filing Date: 2011-12-13
Classification: F01N,F02D,Y02T

Abstract:
1. A malfunction diagnosing apparatus for an internal combustion engine which enables selection of a fuel to be supplied to a fuel tank from a plurality of fuels having different properties, comprising: a refueling determining unit that determines whether fuel has been supplied to the fuel tank; a fuel property sensor that detects a property of the fuel supplied from the fuel tank to a fuel injection valve; an air-fuel ratio control unit that determines an air-fuel ratio correction amount according to a difference between a target air-fuel ratio and an actual air-fuel ratio and according to the property of the fuel sensed by the fuel property sensor to correct a fuel injection quantity of the fuel injection valve using the air-fuel ratio correction amount; and a malfunction diagnosing unit that definitively diagnoses malfunction of the refueling determining unit, malfunction of the fuel property sensor, and malfunction of a fuel system extending from the fuel tank to the fuel injection valve, based on a combination of a result of a determination made by the refueling determining unit, a result of detection conducted by the fuel property sensor, and the air-fuel ratio correction amount or the difference.