Currently, automatic transmission fluid (ATF) and additive manufacturers are addressing the possible introduction of low viscometric fluids (10,000 centipoise) for the next-generation ATF specification. The new fluid specification includes the requirement for improved transmission fluid efficiency.

Southwest Research Institute (SwRI) has developed a unique capability to evaluate the fluid-related effects on transmission efficiency by measuring torque losses at various fluid temperatures. Testing can be conducted in three ways:

Transmission assembly evaluation
Pump performance
Clutch pack drag testing

SwRI operates a test stand that is uniquely configured to allow for absolute configuration of temperature, flow, pressure and speed control of a transmission or transmission component with measurement accuracies of 1 in-lb. When temperature effects are to be investigated, the stand provides for absolute temperature control to 0.5 °F of the set point. This is critical when determining the viscosity-related effects associated with the fluid.

The SwRI test stand is capable of temperature control through −40 to +300 °F. Various instrumentation provides real-time measurements of viscosity, flow, temperature and pressure using coriolis-type flow meters and an SwRI-developed kinematic viscosity transducer. Below is an example of the fluid effects as a function of temperature for an automatic transmission gearbox.

For more information about our drivetrain engineering capabilities and past performance briefs, or how you can contract with SwRI, please contact Douglas Fussner at dfussner@swri.org or (210) 522-3972.

drivetrain.swri.org

Contact Information

Douglas Fussner

Drivetrain Design and Development

(210) 522-3972

dfussner@swri.org

drivetrain.swri.org

Related Terminology

transmission test
facility

transmission testing

automatic
transmissions

drivetrain database

drivetrain
engineering

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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