| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality diagnostic device for a blow-by gas reducing device capable of accurately determining the abnormality of the blow-by gas reducing device while suppressing the excessive enrichment of an air-fuel ratio caused by control over a PCV valve for diagnosing an abnormality. SOLUTION: This blow-by gas reducing device 30 includes a PCV passage 34 introducing blow-by gas to the intake air downstream side of a throttle valve 26 in an intake passage 22, and the PCV valve 36 controlling a blow-by gas flow rate in the passage 34. The abnormality diagnostic device 60 for the blow-by gas reducing device 30 calculates a fuel dilution rate DR of lubricating oil in a crankcase 40, performs first abnormality diagnosing processing if the fuel dilution rate DR is lower than a reference value DRX, and performs second abnormality diagnosing processing for reducing the degree of a change in the controlled variable of the PCV valve 36 in comparison with that in the first abnormality diagnosing processing if an estimate value is larger the reference value DRX. COPYRIGHT: (C)2009,JPO&INPIT
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