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CAViDS Consortium. AMESim Thermal Modeling. A CAViDS Consortium Project. Advisory Board Report March 15, 2012. CAViDS Consortium. 2012 Core Project Objective. Extend AMESim thermal modeling capability beyond that developed in 2011. CAViDS Consortium. Work Plan.
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CAViDS Consortium AMESim Thermal Modeling A CAViDS Consortium Project Advisory Board Report March 15, 2012
CAViDS Consortium 2012 Core Project Objective • Extend AMESim thermal modeling capability beyond that developed in 2011
CAViDS Consortium Work Plan Correlate ongoing member testing with model building and correlation Develop sliding loss model Develop duty cycle model building capability Incorporate in-vehicle convection into AMESim model Develop cooler model building capability
CAViDS Consortium 2012 Technical Status Published report on 2011 work Used thermal model to back-calculate sliding losses generated by loaded temp rise testing with various oils Developed initial model with cooler Wrote LMS Report Developed initial duty cycle model
CAViDS Consortium Eaton Oil Study • Determined biggest test variables • Ambient temperature control • Gear surface finish change with test • Build repeatability • Decided to investigate temperature control • Decided to run tests with honed gears (initial testing done with ground gears)
CAViDS Consortium Oil Cooler Modeling • Used cooler model to determine effect of predicted sliding and churning heat input on maximum temperatures • Discussed input required for cooler modeling with Eaton experts
CAViDS Consortium Latest Interim ResultsOil Cooler Modeling
CAViDS Consortium Interim Results – Oil Cooler Modeling Eaton approach to cooler modeling defined based on experimental results. Need to determine CAT approach.
CAViDS Consortium LMS Request • LMS report OKed and released • LMS presentation today
CAViDS Consortium Duty Cycle • Built simple model • Exercised with constructed data • Predicted HD transmission temperature rise up Eisenhower grade with OD and Direct Transmissions with full and low sump levels • Used ASCII input to define speed and torque time histories • Added oil cooler to duty cycle model
CAViDS Consortium Duty Cycle Model
CAViDS Consortium Duty Cycle Model • Churning Input • Derived relationship for input torque loss vs. speed from analysis of specific transmission at normal fill level • Multiplied by input speed to get power loss • Input to churning loss in temp rise model • Gear Sliding Loss Input • Determined input power • Multiplied by % gear loss per mesh and number of meshes • Input to sliding loss in temp rise model • Time Varying Speed and Torque • AMESim allows 8 segments of time varying input which must be synchronized between speed and torque • Used constant torque and speed in each segment to find loss and temp rise for each segment
CAViDS Consortium Duty Cycle Model • Speed and Torque Input • Simulated up and down a hill • 3 segments of 1000 seconds each • First – Up Hill: 1200 rpm, 1850 LB-FT, 2 meshes • Second – Flat Terrain: 1500 rpm, 1000 LB-FT, 2 meshes • Third – Down Hill with Jake Brake: 1800 rpm, 1000 LB-FT, 2 meshes
CAViDS Consortium Duty Cycle Model • Up Eisenhower Grade on I80 West of Denver • 8 grade segments • Define truck configuration • Engine • Transmission • Axle • Load • Calculate gear, engine speed and torque for each segment • Input results (speed, torque, number of meshes) into AMESim • Calculate resulting temp rise • Big assumptions • Static convection as in test lab at 20 degrees C • Starting temps 100 degrees C
CAViDS Consortium Duty Cycle ModelEisenhower Calculations – First 2 Segments
CAViDS Consortium Duty Cycle ModelEisenhower Grade Results
CAViDS Consortium Duty Cycle ModelEisenhower Grade Results
CAViDS Consortium Duty Cycle ModelEisenhower Grade Results
CAViDS Consortium Duty Cycle Model Wrote ASCII text file to input speed and torque data, duplicating the first example. The results were exactly the same
CAViDS Consortium Duty Cycle Model with Cooler
CAViDS Consortium Duty Cycle Model with Cooler
CAViDS Consortium Duty Cycle Model • Future Work • Add churning model to duty cycle model within AMESim • Incorporate sliding model within AMESim • Prepare for in vehicle convection model • Continue to evaluate/correlate incoming data
CAViDS Consortium Viscous Fan Drive Model
CAViDS Consortium Viscous Fan Drive Model • Parameter Assumptions • 50 wt oil • 51 ml volume • Oil convective area 2000 mm^2 • Oil convective characteristic length 150 mm • Oil velocity 150 m/sec • Changenet forced convection equation • Air convective area 4000 mm^2 • Air convective characteristic length 150 mm • Relative velocity for convection 150 m/sec • Changenet forced convection equation • Drive material alumuinum • Drive mass 5 kg
CAViDS Consortium Viscous Fan Drive Model