The invention relates to a method for determining the high-temperature
evaporation loss of lubricating oil. According to the method, an aluminum
block heater in accordance with an SH / T 0661 method is adopted, and a ring-shaped heater of an
air preheater is closed to determine the
evaporation loss of the lubricating oil by adopting a pressure regulation type
heating temperature control mode, wherein a sample cup and a cover of an
evaporator assembly accord with provisions of a GB / T 7325 method, and an
exhaust pipe and a cover of the
evaporator assembly accord with provisions of the SH / T 0661 method. The method is characterized by comprising the following determination steps of: thoroughly cleaning all components of the
evaporator assembly; setting a test temperature and an air flow rate; keeping the temperature of the aluminum
block heater and the air flow rate for at least 0.5 hour; weighing 10+ / -0.05g of a sample; testing for 6.5+ / -0.1 hours; and calculating the
evaporation loss X of the lubricating oil. According to the method, the evaporation loss of the lubricating oil at 150 to 250 DEG C can be accurately determined, and design requirements for a novel aircraft engine can be met.