Designing more fuel-efficient vehicles requires that considerations be given to the thermal management requirements of vehicle propulsion systems. Exterior appearance, vehicle function, and thermal limits all have a direct impact on the design of the cooling airflow system. For hybrid and all-electric vehicles, batteries and thermal management present unique integration challenges. To address these challenges, suppliers and vehicle manufacturers must work as partners in the selection and packaging of batteries and under-hood cooling components. Critical to a successful design effort is a thorough understanding of the vehicle-level trade-offs and thermal issues that affect system performance.

This two-day seminar will provide attendees a vehicle-level perspective of powertrain and battery cooling airflow systems, including the unique challenges of hybrid and all-electric vehicles. Product design constraints related to front-end, batteries, and underhood components will be discussed. Special emphasis will be placed on the numerous battery integration issues and thermal management characteristics. A lumped capacitance model will be used to pull together battery thermal analysis concepts and the trade-off with energy required for cooling. Attendees will also learn about cooling airflow (fan & ram), HEV/EV battery thermal management, heat generation rate, grille openings, thermal recirculation, system resistance, cooling drag, and powertrain heat rejection. The radiator heat transfer equation will be used to describe the influence of vehicle-level and subsystem requirements on powertrain cooling.

Included in this seminar is the SAE paper A Systems Engineering Approach to Engine Cooling Design; The 44th L. Ray Buckendale Lecture.

Case studies will be used to reinforce concepts and attendees should bring a calculator for these in-class activities.

• List fundamental considerations of grille openings and underhood airflow systems
• List battery thermal management requirements and integration issues
• Describe options for HEV/EV battery thermal management
• Conduct a steady-state analysis of a low temperature cooling airflow system
• Use the fan/ram airflow map to track system operation and performance
• List major factors and considerations in airflow system resistance and optimization
• Estimate installed-powertrain radiator heat rejection for system analysis
• Conduct an analysis of a powertrain cooling system proposal against thermal limits
• Draft alternatives for program management discussions on cooling system trade-offs

• OEM vehicle perspective
  • Powertrain cooling airflow system
  • Underhood package and cooling fan alternatives
  • Suppliers
  • System & sub-system requirements
  • Thermal recirculation
• HEV and EV Battery Thermal Management
  • HEV/EV vehicle classifications
  • Battery thermal characteristics
  • Heat generation rate
  • Internal and external heating
  • Lumped capacitance model
  • Cooling system options
  • Thermal management system characteristics
  • Electric machines and power electronics
  • Low temperature cooling airflow system calculation
  • Vehicle ¿ BTMS integration issues and challenges
  • Some current vehicle design solutions
  • Current technology, challenges, future development
  • Underhood airflow patterns

• Thermodynamics Review
  • First Law
  • Radiator heat transfer equation
  • Radiator effectiveness and pressure drop
  • SCFM
  • Total-pressure
• Powertrain Heat Rejection
  • Estimating radiator heat rejection; SAE Dynamometer engine test procedures
  • Engine mean effective pressure (MEP)
  • Engine specific heat rejection (SHR)
  • Engine oil temperature
• Front-End Airflow
  • Airflow patterns; idle, ram, exit, underhood
  • Airflow restrictions; system resistance, underhood, grille opening
  • Sizing cooling openings; inlet total-pressure recovery
  • Ram airflow and cooling drag
• Cooling Fans
  • Classification and Specific speed
  • Characteristic curves and performance matching
  • Axial fan systems, design parameters, shroud immersion and tip clearance
  • Fan laws
  • Shrouds
  • System airflow road map ¿ fan and ram
• Powertrain Cooling System Case Study
  • Define a system to meet thermal and product requirements
  • Evaluate system alternatives
  • List and discuss options for program management trade-off discussions
• Wrap-Up Discussions

Mr. Williams is the principal at Airflow & Aerodynamics Engineering, LLC and an independent consultant specializing in the design and development of thermal management systems and vehicle aerodynamics. He is an adjunct faculty member at the Lawrence Technological University (LTU) and a guest lecturer for their MSAE Program on Automotive Mechanical Systems. In addition to his consulting work, he conducts professional development seminars for engineers on cooling systems, HEV battery thermal management, and road vehicle aerodynamics. Mr. Williams has over thirty years engineering management experience in product development at Ford Motor Co. Additionally, he was an aerodynamics project leader with the USAF Aeronautical Systems Division at Wright-Patterson Air Force Base, Ohio where he specialized in engine/aircraft integration, gas turbine engine performance, inlet design, and aircraft mission analysis. An active member of the SAE, Mr. Williams has authored over twenty technical papers, given invited lectures at major mid-west universities, and has received professional awards and international recognition for his innovative work. He is a recipient of the Henry Ford II Technology Award, the SAE Industrial Lectureship Award, the SAE Oral Presentation Award, and the SAE Forest R. McFarland Award. He holds a B.S. in Aeronautical Engineering from the University of Detroit and an M.S. in Aerospace/Mechanical Engineering from the United States Air Force Institute of Technology.