| 摘要 |
Individual cylinder output deviations from a normal operating engine cylinder are detected via an analysis of crank shaft speed fluctuations. In the detection phase, the engine is operated at a steady state low idle condition, and engine speed data is collected over a plurality of engine cycles. This data is then averaged, filtered and compared to expected engine speed data. A substantial deviation from the expected speed data in the region of crank shaft angles associated with an individual cylinder during its power stroke adjacent its top dead center position indicates a power level deviation in that cylinder. The magnitude of the power level deviation can then be assessed through a similar procedure where engine speed data is collected, averaged, filtered and compared to expected engine speed data when the engine is operating in a steady state rated condition.
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