| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality diagnostic device for a blow-by gas reducing device, accurately determining an abnormality of the blow-by gas reducing device without using a sensor detecting the opening of a PCV valve. 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 forcibly changes the controlled variable of the PCV valve from a controlled variable with the opening of the valve 36 maintained to a first opening when the device 30 is normal to a controlled variable with the opening of the valve 36 maintained to a second opening, during ISC control, and determines that the blow-by gas reducing device 30 is abnormal if a difference in a feedback controlled variable before and after forcible control reaches a reference value or below. COPYRIGHT: (C)2009,JPO&INPIT
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