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CAViDS Consortium. Transmission Thermal Limit Analysis. A CAViDS Consortium Project. Advisory Board Report December 5, 2013. CAViDS Consortium. Project Objective. Develop process to evaluate power and load application limits of uncooled transmissions. CAViDS Consortium. Steps.
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CAViDS Consortium Transmission Thermal Limit Analysis A CAViDS Consortium Project Advisory Board Report December 5, 2013
CAViDS Consortium Project Objective • Develop process to evaluate power and load application limits of uncooled transmissions
CAViDS Consortium Steps • Define Vehicle Characteristics • Define Worst Case Grade Characteristics • Calculate Engine Speeds and Loads Required to Ascend Grade • Determine Transmission Heat Generated at Each Condition • Determine Temperature
CAViDS Consortium Vehicle Definition Status - Green Engine Ratings Based on published torque-speed curves Transmission Ratios Well documented Axle Ratio Well documented Load Variable
CAViDS Consortium Grade Profile Status - Green Baker Grade As defined on website NAVTEQ web link http://www.navteq.com/company.htm
CAViDS Consortium Predicted Torque-Speed-Gear History Status - Yellow Relying on engine percent torque too unstable Measuring driveline torque may be better alternative Should verify aerodynamic and rolling loss calculations Could automate process with software development
CAViDS Consortium Predicted Heat Input Status - Green No Load Losses Changenet churning, synchronizer, and bearing loss prediction spreadsheet (2011) Gear Sliding Losses LDP predicted and SwRI measured friction factors (2013) Predicted no load losses could use more verification Could do point to point verification between LDP and SwRI
CAViDS Consortium Temperature Rise (Work to Date) Status - Yellow Need more work on defining in-vehicle convection Local air velocity and temperature needs definition Develop gear sensitive friction sub-model within AMESim
CAViDS Consortium Temperature Rise Calculation Inputs Status - Yellow
CAViDS Consortium Conclusions • Process needs some tuning • Has potential to be valuable tool in assessing risks of no coolers and thereby assessing customer value of heat generation improvements like honing additional gears • Could automate process in a single step or two step software package
CAViDS Consortium Recommendations • Measure driveline torque up Baker Grade with strain gaged drive shaft • Verify aerodynamic and rolling loss calculations • Measure local air velocity and temperature up Baker Grade local to transmission • Automate torque-speed-gear calculation process • Do point to point comparison of LDP and SwRI results • Verify no-load calculations with measurements • Develop gear sensitive sub-model within AMESim