Patent Number: 7,611,901

Title: Method for determining the content of diesel fuel in a lubricating oil of a combustion engine

Abstract: 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 C.sub.5 hydrocarbon such as a C.sub.5 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 C.sub.5 hydrocarbon such as a C.sub.5 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 ##EQU00001## 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.

Inventors: Fitamen; Eric (Fontenay Aux Roses, FR), Tiquet; Laurent (Gallardon, FR)

Assignee: Renault S.A.S.

International Classification: G01N 33/30 (20060101); G01N 30/02 (20060101)

Expiration Date: 1/03/02017