METHOD OF ESTIMATING DEGREE OF DEGRADATION OF ENGINE OIL Russian patent published in 2015 - IPC G01N33/28 

FIELD: chemistry.

SUBSTANCE: method employs a gas analyser with n=3-8 piezoelectric crystal resonators with natural oscillation frequency of 10-15 MHz, whose electrodes are modified with sorbents which are selective and sensitive to engine oil degradation marker gases; the method includes collecting an analysed engine oil sample and placing in a sealed vessel for saturation of the gas phase with the oil degradation marker gases; after establishing equilibrium in the gas-liquid system, without breaching the air-tightness of the vessel, using a sampler to collect 1-5 cm³ of the equilibrium gas phase and injecting said sample into a closed detection cell of the gas analyser; detecting change in the oscillation frequency of the modified piezoelectric crystal resonators for 1 minute; based on the results of responses in a program, constructing the "visual print"; calculating the area thereof S_v.p, arbitrary units²; calculating the difference ΔS between the area of the "visual print" for the analysed sample S_i and the area of the "visual print" for a standard engine oil sample S_st using the formula ΔS=(S_i-S_st)/S_st×l00%; if the relative area difference ΔS≤30%, the engine oil meets the standard, if ΔS≥30%, the degree of degradation of the engine oil is critical, and if ΔS>45% the engine oil is spent and should be replaced.

EFFECT: more accurate, faster and easier evaluation.

1 ex, 1 dwg