Patent ID: 6917865

Claim:
An engine oil degradation-determining system that determines a degradation level of engine oil for lubricating an internal combustion engine, the engine oil degradation-determining system comprising: operating condition-detecting means for detecting an operating condition of the engine; degradation level parameter-calculating means for calculating a degradation level parameter indicative of a degradation level of the engine oil, based on the detected operating condition; degradation-determining means for determining the degradation level of the engine oil, based on the calculated degradation level parameter; oil level-detecting means for detecting an oil level of the engine oil; and degradation level parameter-correcting means for correcting the degradation level parameter in a direction of indicating a lower degradation level, when the detected oil level was equal to or lower than a predetermined lower limit value before stoppage of the engine, and is equal to or higher than a predetermined upper limit value higher than the predetermined lower limit value after start operation of the engine following the stoppage.