A critical factor that will dramatically affect a vehicle's performance and fuel consumption is the shift strategy selected by the vehicle manufacturer. Current production automobiles and trucks use complex electronic control modules to affect the shift strategy based on 60 to 80 sensor inputs providing information about the operating conditions of the vehicle. To improve vehicle performance, Southwest Research Institute (SwRI) evaluates various powertrain and transmission control modules to determine their shift strategy as a function of changing operating conditions.

A complete vehicle was mounted on a specially configured dynamometer test stand capable of simulating road conditions such as aerodynamic drag, tire rolling resistance, and slope. The vehicle was instrumented to monitor selected powertrain control module input and output parameters such as:

Throttle position
Wheel speed
Engine speed
Transaxle shift solenoid actuation
Torque converter solenoid actuation
Transaxle fluid temperature

Automatic transaxle shift strategy was mapped at the following conditions:

10 throttle positions
Vehicle speeds to 65 mph
2 transaxle fluid temperatures
2 manifold absolute pressures
2 intake air temperatures
2 exhaust gas recirculation conditions

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

Contact Information

Douglas Fussner

Drivetrain Design and Development

(210) 522-3972

dfussner@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.

September 30, 2008