2010 NDIA GROUND VEHICLE SYSTEMS ENGINEERING AND TECHNOLOGY SYMPOSIUM MODELING & SIMULATION, TESTING AND VALIDATION (MSTV) MINI-SYMPOSIUM AUGUST 17-19 DEARBORN, MICHIGAN THERMAL MANAGEMENT SYSTEM MODELING AND OPTIMIZATION FOR HEAVY HYBRID ELECTRIC MILITARY VEHICLES 1 S. Park M. Kokkolaras University of Michigan Ann Arbor, MI A. Malikopoulos General Motors Warren, MI B. AbdulNour J. Sedarous General Dynamics Land Systems Sterling Heights, MI D. Jung University of Michigan-Dearborn Dearborn, MI ABSTRACT A thermodynamics-based Vehicle Thermal Management System (VTMS) model for a heavy-duty, off-road vehicle with a series hybrid electric powertrain is developed to analyze the thermal behavior of the powertrain system and investigate the power consumption under different vehicle driving conditions. The simulation approach consists of two steps: first, a Series Hybrid Electric Vehicle (SHEV) powertrain is modeled; the output data of the powertrain system simulation are then fed into a cooling system model to provide the operating conditions of the powertrain components. Guidelines for VTMS configuration was developed based on the vehicle simulation results and the operating conditions of powertrain components. Based on the guidelines, a VTMS configuration for the hybrid vehicle was created and used for designs of experiments to identify the factors that affect the performance and power consumption of each cooling system. Design space exploration techniques are then applied to investigate trade-offs and determine near-optimal size of components such that power consumed by fans and pumps is minimized. Finally, gradient-based optimization is used to fine-tune the component sizing subject to performance and geometry constraints. The cooling system design study demonstrates that the configuration and sizing of an SHEV cooling system is different from that of a conventional cooling system because of additional heat sources, increased complexity of component operations and interactions, and the dependency of parasitic power consumption on driving modes. INTRODUCTION Series Hybrid Electric Vehicles (SHEVs) for military applications can offer improved fuel economy, exportable electric power, enhanced low speed maneuverability, and low acoustic signature for stealth operation. Compared with conventional vehicles, however, SHEVs need additional powertrain components such as a generator, driving motors, a battery pack, and a power bus, all of which make the thermal management system more complicated. Moreover, military vehicles need more reliable thermal management system for the vehicle’s survivability because combat vehicles are operated under desert-like conditions allowing a high tractive effort to weight ratio. Thus, a more strategic approach is required when designing a thermal management system for military SHEVs. Increased cooling demands in SHEV and additional hardware make it challenging to provide an effective cooling system that has minimal impact on fuel economy and cost. Typically, SHEVs tend to have a dedicated cooling system for the hybrid components due to their different requirements. The additional cooling system increases the hardware, cost, weight, and affects the vehicle fuel economy. Packaging issue is another critical challenge in Vehicle Thermal Management System (VTMS) 1 Approved for Public Release, Distribution Unlimited, GDLS approved, Log No. 2010-73, dated 07/08/10