SAE CLASSIFICATION
Kinematic viscosity measured at 100°C defines SAE degrees from 20 to 60 for rising levels of viscosity. Dynamic viscosity at low temperatures defines the SAE "W" degrees, from the initial "winter", from 0W to 25W on the basis of viscosity levels measured at temperatures from -35° to -5°C. The temperature represents the lowest possible temperature at which the engine can be started when lubricated with an oil of the corresponding SAE degree (e.g. a 15W oil makes it possible to start the engine at up to -20°C). The minimum pumping temperature is the minimum temperature at which oil, in addition to allowing start up, can flow freely and lubricate the critical parts of the engine.
SAE J300 JANUARY 2009 (ENGINE OILS)
The most widely used system for engine oil viscosity classification is that established by the Society of Automotive Engineers (SAE) in the USA. In this system two series of viscosity grades are defined – those containing the letter W and those without the letter W. Grades with the letter W are intended for use at lower temperatures and are based on a maximum low temperature viscosity and a maximum borderline pumping temperature, as well as a minimum viscosity at 100°C. The low temperature viscosity is measured by means of a multi-temperature version of ASTM D2602 ‘Method of Test for apparent Viscosity of Motor Oils at Low temperature using the Cold Cranking Simulator’.
Viscosities measured by this method have been found to correlate with engine speeds developed during low temperature cranking.
SAE J300.jpg 85,15К 2 Количество загрузок:
В книжке на машину рисуют картинку со стрелками - какое масло в каком климатическом регионе (по темературе) использовать. Если картинка правильно напечатана, на ней видно, что масло с цифрами 10W рекомендуют при температуре выше -25С.
Верхний предел - выделил в цитате - измеряют вязкость при 100С - рабочей температуре блока цилиндров.