| 摘要 |
PROBLEM TO BE SOLVED: To secure a frequency of executing malfunction diagnosis of an intake pipe pressure sensor in an engine whose combustion mode is changed over between a stratified charge combustion mode and a homogeneous combustion mode. SOLUTION: When a combustion mode change-over flag is on, this malfunction diagnosis device reads an output value for the intake pipe pressure sensor at starting change-over. Then, when the combustion mode change-over flag is off, it reads an output value for the intake pipe pressure sensor at finishing change-over. It finds an output change amountΔMAP of the intake pipe pressure sensor before and after the change-over of the combustion mode and determines the malfunction or not of the intake pipe pressure sensor depending on whether the output change amountΔMAP is a predetermined malfunction determining value K or smaller, or not. When diagnosing the malfunction or not, it checks whether the combustion mode is normally changed over or not in accordance with an air-fuel ratio detected by an exhaust gas sensor 28. COPYRIGHT: (C)2007,JPO&INPIT
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