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	Shear stability evaluation equipment
	A polymer-containing fluid is passed through a diesel injector nozzle at a shear rate that causes polymer molecules to degrade.

The shear stability procedure is an API CJ-4-approved test that evaluates the shear stability of polymer-containing fluids. This evaluation method measures the percent viscosity loss at 100°C of polymer-containing fluids when evaluated by a diesel injector apparatus procedure that uses European diesel injector test equipment. The viscosity loss reflects polymer degradation due to shear at the nozzle.

Shear Stability Evaluation Equipment and Procedure

The shear stability apparatus consists of the following:

• Fluid reservoir

• Double-plunger pump with electric motor drive

• Atomization chamber with diesel injector spray nozzle

• Fluid-cooling vessel, installed in an area with an ambient temperature of 20 to 25°C (68 to 77°F)

Shear Stability Evaluation Method and Summary

The shear stability procedure evaluates the percent viscosity loss for polymer-containing fluids resulting from polymer degradation in the high shear nozzle device. Thermal or oxidative effects are minimized. This test method is used for quality control purposes by manufacturers of polymeric lubricant additives and their customers.

A polymer-containing fluid is passed through a diesel injector nozzle at a shear rate that causes polymer molecules to degrade. The resultant degradation reduces the kinematic viscosity of the mechanical shear stability of the polymer containing fluid.

Pass/Fail Criteria

For more information about our shear stability evaluation capabilities, or how you can contract with Southwest Research Institute (SwRI), please contact Becky Grinfield at bgrinfield@swri.org or (210) 522-3652.

shearstability.swri.org

| Engine Lubricants Research Department | Fuels and Lubricants Research Division | SwRI Home |

Southwest Research Institute^® (SwRI^®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 11 technical divisions.

December 28, 2012