US 6,917,865 B2 · Engine oil, degradation-determining system and method, and engine control unit

Abstract

There is provided an engine oil degradation-determining system which is capable of accurately detecting whether or not engine oil has been replenished, to thereby enhance accuracy of determination as to a degradation level of engine oil in use, at a low cost. A crankshaft angle sensor detects the engine rotational speed of an internal combustion engine. An ECU calculates a cumulative revolution number indicative of a degradation level of engine oil. An oil level sensor detects an oil level of the engine oil. When the detected oil level, which was equal to or lower than a predetermined lower limit level before stoppage of the engine, is equal to or higher than a predetermined higher limit level after start operation following the stoppage, the calculated cumulative revolution number is corrected in the direction of indicating a lower degradation level.

Claims15

Dependent claims

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.

4 more elements

An engine oil degradation-determining method of determining a degradation level of engine oil for lubricating an internal combustion engine,

the engine oil degradation-determining method comprising the steps of:
detecting an operating condition of the engine;
calculating a degradation level parameter indicative of a degradation level of the engine oil, based on the detected operating condition;
determining the degradation level of the engine oil, based on the calculated degradation level parameter;
detecting an oil level of the engine oil;
and
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.

4 more elements

An engine control unit including a control program for causing a computer to determine a degradation level of engine oil for lubricating an internal combustion engine,

wherein the program causes the computer to detect an operating condition of the engine, calculate a degradation level parameter indicative of a degradation level of the engine oil, based on the detected operating condition, determine the degradation level of the engine oil, based on the calculated degradation level parameter, detect an oil level of the engine oil, and correct 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.

Dependencies are inferred from the claim text.

Engine oil, degradation-determining system and method, and engine control unit

Life of this patent

Engine oil, degradation-determining system and method, and engine control unit

Life of this patent

Abstract

Claims15