SwRI has compiled friction data from a variety of engines into a comprehensive database of engine and component friction. Measured friction losses are useful when validating computational codes. The Institute quantifies the torque losses within a transmission gearbox for transmission manufacturers. This information is essential for initial product development, on-going improvement, vendor manufacturing process verification, modeling, and simulations. To determine torque losses under various test conditions, precision measurements are made with specialized equipment.
Efficiency varies by up to one percent with five-degree mounting angle difference.
Transmission Mounting Angle Fluid churning and windage losses are major contributions to manual transmission internal torque loss and are directly affected by the installation angle of the transmission. Varying the mounting angle on the test stand, SwRI determines the effects of mounting angle on efficiency. The internal torque losses of manual transmissions are greatly affected by fluid viscosity and temperature. The temperature effect has become particularly significant as lighter weight automatic transmission fluids have replaced heavier lube oils. This plot shows transmission efficiency as a function of fluid temperature.