Engine self-diagnosis apparatus and control apparatus
The present invention relates to a self-diagnosis apparatus and control apparatus of an engine (internal combustion engine) for use in vehicles such as a car, particularly to a self-diagnosis apparatus for self-diagnosing an abnormality of an air/fuel ratio detection apparatus, and a control apparat...
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| Main Authors | , , , |
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| Format | Patent |
| Language | English |
| Published |
29.10.2002
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| Online Access | Get full text |
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| Summary: | The present invention relates to a self-diagnosis apparatus and control apparatus of an engine (internal combustion engine) for use in vehicles such as a car, particularly to a self-diagnosis apparatus for self-diagnosing an abnormality of an air/fuel ratio detection apparatus, and a control apparatus.
There is disclosed an apparatus in which changes of linear A/F sensor or engine response characteristics can be detected with high precision in a broad range during operation of an engine. The apparatus includes a controller for controlling an air/fuel ratio of each cylinder of a multiple cylinder engine, and a linear A/F sensor for emitting an output which is proportional to the air/fuel ratio of an exhaust tube assembly. The air/fuel ratio of a specific cylinder is changed by a predetermined amount, a vibration component amplitude or a frequency component based on an engine rotation number is extracted from a signal obtained from the linear A/F sensor , and the response characteristics of an air/fuel ratio detector or the engine are detected from the amplitude or a power of the frequency component. |
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