SAE classification

The SAE classification has existed since 1911 and has undergone several revisions. The latest version is designated by the symbol SAE J 300 followed by the date of the latest revision. 

A lubricant should be characterized by its viscosity at low temperature (-18°C) to account for its behavior during cold weather starting and by its viscosity at high temperature (100°C). Values of these two viscosities are based on the SAE classification. See Chapter 6. 

However, multigrade oils do not behave as Newtonian fluids and this is primarily due to the presence of polymeric viscosity index improvers. The result is that the viscosity of multigrade oils is generally higher at -18°C (0°F) than is predicted by extrapolation from 38°C (100°F) and 99°C (210°F) data, the extent of the deviation varying with the type and amount of viscosity index improver used. To overcome this, the SAE classification is based on a measured viscosity at -18°C (0°F) using a laboratory test apparatus known as a cold cranking simulator (ASTM D-2602). 

As with other engine lubricants, viscosity is used to divide turbine lubricants into various grades, not by using the SAE classification system but by the lubricant s kinematic viscosity at 100°C. The grades currently available are 3, 4, 5 and 7.5 cSt. Some of the more common specifications used to define these are shown in Table 11.1. 

According to SAE classification, tractor transmission oils are divided into 6 classes (Table 1.9) with regard to viscosity. 

Table 1.9 The SAE classification for transmission oils with regard to viscosity.

The classification of motor oils has not been completed in the ISO standard because the technical differences between motors in different parts of the world, particularly Europe and the United States, make the implementation of a single system of classification and specifications very difficult. In practice, different systems coming from national or international organizations are used. The best known is the SAE viscosity classification from the Society of Automotive Engineers, developed in the United States. 

Fig. 1. SAE J200 Classification system for ASTM No. 3 oil where in volume swell nr = no requirement. EPDM is ethylene—propylene—diene monomer HR, butyl mbber SBR, styrene—butadiene mbber NR, natural mbber VMQ, methyl vinyl siUcone CR, chloroprene FKM, fluoroelastomer FVMQ, fluorovinyl methyl siUcone ACM, acryUc elastomers HSN, hydrogenated nitrile ECO, epichlorohydrin and NBR, nitrile mbber.

Specifications. EZ compounds meet class EK in the SAE automotive mbber classification J200. Line callouts have been developed for 50, 70, and 80 durometer materials. Specific compounds meet requirements for O-rings for military aerospace appHcations identified in MIL-P-87175,... 

This classification was devised by the Society of Automotive Engineers (SAE) in America by dividing the viscosity span into four and giving each of the divisions a number - SAE 20, 30, 40 and 50. The thinnest (SAE 20), for example, covered the range 5.7-9.6cSt specified at 210°F, which was considered to be a temperature typical of a hot engine. (The SAE originally specified temperatures in °F, because they were the convention. Today, temperatures are quoted in °C.)... 

SAE Numbers—A classification of motor, transmission, and differential lubricants to indicate- viscosities, standaidized by the Society of Automotive Engineers. They do not connote quality of the lubricant. 

API Engine Service Categories— gasoline and diesel engine oil quality levels established jointly by API, SAE, and ASTM, and sometimes called SAE or API/SAE categories formerly called API Engine Service Classifications. API Service Categories are as follows ... 

SAE (Society of Automotive Engineers)—organization responsible for the establishment of many U.S. automotive and aviation standards, including the viscosity classifications of engine oils and gear oils. See SAE viscosity grades. 

SAE viscosity grades-engine oil classification system developed by the Society of Automotive Engineers (SAE), based on the measured viscosity of the oil at either -18°C (-0.4°F), using test method... 

After 1981, the low-temperature portion of the SAE viscosity classification system is to be superseded by a revised system, following an 18-month (1980-81) phase-in. The new system introduces the following key changes 1) two new grades are added—a 0W grade for... 

Lubricant requirements and specifications. The development of North American classification systems for the SAE began in 1911 on the basis of viscosity alone. In 1947, the API (American Petroleum Institute) developed a performance classification system for engine oils in terms of regular, premium and heavy duty lubricants. By 1952, the API and ASTM (American Society for Testing and Materials) further advanced the system to generally classify engine oils. In 1970, the TRIPARTITE of API, ASTM, and SAE was established to manage a completely new API classification system, see Fig. 2.12 (Haycock, 1993). 

Viscosity classification In the description of SAE grade oils, such as SAE 5 W, does the W designate a viscosity that applies to warm or winter temperatures Which multigrade engine oil designation is incorrect SAE 5W-20, SAE 10W-50, or SAE 5W-10W-30 ... 

Table 1. Engine Oil Viscosity Classification SAE J300 (April 1997)a...

A new proposed SAE Viscosity Classification not only reflects lower than 0°F temperature cranking characteristics of an oil, but also covers low temperature pumpability characteristics (j), 10). Low temperature cranking success without oil pump-ability could result in oil starvation and subsequent engine damage. This new proposed classification attempts to establish a maximum cranking viscosity and then classifies oils according to what temperature they match this viscosity. It also includes a low shear test (mini-rotor viscometer) to duplicate pumpability of the oil at various low temperatures. Needless to say, minimum... 

The viscosity of automotive engine oil is the main controlling property for manufacture and for selection to meet the particular service condition using the American Society of Automotive Engineers (SAE) viscosity classification. The higher-viscosity oils are standardized at 210°F (99°C), and the lighter oils that are intended for use in cold weather conditions are standardized at 0°F (-18°C). 

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