The invention discloses a method for rapidly measuring physical and
chemical quality indexes of in-use lubricating oil, which comprises the following steps: in a first step, collecting representative samples as a
training set; in a second step, measuring an
infrared spectrum decay index of the in-use lubricating oil; in a third step, measuring in-use oil physical and
chemical quality indexes; in a fourth step, adopting a gradual
linear regression method to carry out optimization on the
infrared spectrum decay index and establishing a multiple
linear regression equation of the physical and chemical indexes and the
infrared spectrum decay index; and in a fifth step, for an in-use oil sample, firstly measuring the infrared spectrum decay index and then utilizing the regression equation established in the fourth step to calculate the physical and
chemical quality indexes. The method of the invention can rapidly measure seven physical and chemical quality indexes of the in-use lubricating oil, i.e. a kinematic
viscosity at the temperature of 40 DEG C, a kinematic
viscosity at the temperature of 100 DEG C,
water content, a
total acid number (TAN), a
total base number (TBN), a
flash point and a
pour point, monitor the quality decay of the lubricating oil, guide to change the oil and guarantee the normal operation of the engine.