Thermal Modeling of Lithium-Ion Energy Storage Systems for Hybrid Electric Vehicles Using Computational Fluid Dynamics with Conjugate Heat Transfer

The success and performance of a Hybrid Electric Vehicle (HEV) relies largely on its Energy Storage System (ESS). High temperatures and thermal variations can significantly affect a battery\u27s performance and lifecycle. An effective thermal management system is vital to the health and safe operation of the ESS\u27s batteries. A well designed thermal management system begins with the accurate prediction of the battery\u27s thermal conditions. In hot climates, HEVs may be required to operate within ten degrees Celsius of the maximum safe operating temperature of their batteries. This study aims to evaluate the thermal management system of a lithium-ion based energy storage system designed for HEV applications. The analysis uses estimated current values from powertrain simulation software, fundamental heat transfer principles, finite element analysis (FEA), and computational fluid dynamics (CFD) tools to predict the temperature distributions in battery modules

ES2008-54271 Simulation, Analysis and Systems Engineering of a Hybrid-Electric Race Car

ABSTRACT For the past two years, Embry-Riddle has participated in the SAE Formula Hybrid competition. As part of the competition, a team of students analyze, design, and build a fully functional hybrid-electric race car. As an academic competition, the event is designed to allow a wide variety of system configurations and fuel choices. In order to optimize the vehicle characteristics, simulate vehicle performance, and build control laws, the design team created a Simulink model of the race car. As a recently created design competition, the SAE Formula Hybrid event offers an opportunity for both design innovation and system engineering. To develop a concept for the competition, the ERAU team developed detailed simulations of the vehicle in Simulink. Since the competition allows a variety of energy storage devices, engines, fuels, driveline configurations, and control systems, the development of a system dynamics model was not straight-forward. Further, system components for this project are constrained by some rules and practical constraints. The vehicle configuration was selected to be a parallel hybrid using a 250cc gasoline engine and 7.2kW DC motor with 1500F ultra-capacitor energy storage, with an unusual control strategy. The results of the Simulink model were used to predict how this vehicle configuration compares to other design choices including alternative fuels, energy storage devices and control strategies. The performance of the actual vehicle at the 2008 SAE Formula Hybrid competition, which occurs May 2008, will be presented at the conference

Truck Rear View Mirror Drag Reduction Using Passive Jet Boat Tail Flow Control

This paper conducts numerical simulation and wind tunnel testing to demonstrate the passive flow control jet boat tail (JBT) drag reduction technique for a heavy duty truck rear view mirror. The JBT passive flow control technique is to introduce a flow jet by opening an inlet in the front of a bluff body, accelerate the jet via a converging duct and eject the jet at an angle toward the center of the base surface. The high speed jet flow entrains the free stream flow to energize the base flow, increase the base pressure, reduces the wake size, and thus reduce the drag. A baseline heavy duty truck rear view mirror is used as reference. The mirror is then redesigned to include the JBT feature without violating any of the variable mirror position geometric constraints and internal control system volume requirement. The wind tunnel testing was conducted at various flow speed and yaw angles. The condition selected for CFD (computational fluid dynamics) simulation is at high way speed of 70 miles/h, zero yaw angle and Reynolds number of 4.8x105. The wind tunnel testing measured a drag reduction of 10.1% due to the JBT configuration. The 3D CFD based on RANS model predicts the drag reduction of 11.0%, an excellent agreement. This study confirms that the JBT device is very effective for heavy duty truck mirror drag reduction from both numerical simulation and wind tunnel experiment