摘要 |
A method for determining proportion of diesel fuel in a lubricating oil of a combustion engine, including: forming a mixture containing an oil sample and a C5 hydrocarbon such as a C5 alkane; injecting the mixture into the injector of a gas chromatograph; establishing a chromatograph of the sample; determining a first parameter M representative of the area of a peak associated with the C5 hydrocarbon such as a C5 alkane; determining a second parameter C representing of the area of at least one peak associated with a hydrocarbon representative of diesel fuel; and determining the proportion T of diesel fuel by a formula T = C / ( M ) - b a in which a and b are constants defining equation y=ax+b of a calibration straight line of the ratio between the second and the first parameters as a function of the proportion of diesel fuel.
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