| 摘要 |
PROBLEM TO BE SOLVED: To expand diagnostic range and improve diagnostic precision of irregularity diagnostic of a valve timing control system. SOLUTION: Sampling of a target advanced angle integration amountΣVTT which integrated target advanced angle variation amountsΔVTT and an actual advanced angle integration amountΣVT which integrated actual advanced angle correction variation amountΔVTH corrected by an actual advanced correction coefficient KH is carried out for a predetermined period, ratio of the target advanced angle integration amountΣVTT to the actual advanced angle integration amountΣVT is calculated as a diagnostic value DIAG (S101, S102-S111). When the diagnosis value DIAG exceeds a determination value DIAGset1, the valve timing control system is determined as irregular (S112, S114) and a control command to set a current target advanced angle value VTT as most delayed angles is issued (S115). Consequently, irregularity is precisely detected even in acceleration and deceleration or the like, irregularity is precisely detected even if response of actual advance angle to the target advance angle is deteriorated. COPYRIGHT: (C)2004,JPO
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