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Technical Paper

Design of a Portable Thermoelectric Convective Cooling System for Neighborhood Electric Vehicles and Other Applications

2019-04-02
2019-01-0499
Automotive technology is increasingly reliant on electrically driven accessories, systems, and payloads thanks to the rising popularity of electric and hybrid electric vehicles. Solid state and similar purely electrical solutions such as thermoelectric devices are eminently preferable sources for thermal management in neighborhood electric vehicles (NEVs) and similar short-range automobiles which often do not come stock with a climate control system. Directed convection strategies such as zone cooling using DC electric current are a natural fit for the infinitely scalable thermal control architecture possible with thermoelectrics. One such prototype device, actuated by thermoelectric devices, has been developed to meet a variety of thermal management needs with a versatile, portable system suitable for NEVs, micro cars without air conditioning, or even more specialized cooling needs.
Technical Paper

An Innovative Electric Motor Cooling System for Hybrid Vehicles - Model and Test

2019-04-02
2019-01-1076
Enhanced electric motor performance in transportation vehicles can improve system reliability and durability over rigorous operating cycles. The design of innovative heat rejection strategies in electric motors can minimize cooling power consumption and associated noise generation while offering configuration flexibility. This study investigates an innovative electric motor cooling strategy through bench top thermal testing on an emulated electric motor. The system design includes passive (e.g., heat pipes) cooling as the primary heat rejection pathway with supplemental conventional cooling using a variable speed coolant pump and radiator fan(s). The integrated thermal structure, “cradle”, transfers heat from the motor shell towards an end plate for heat dissipation to the ambient surroundings or transmission to an external thermal bus to remote heat exchanger.
Journal Article

Automotive Waste Heat Recovery after Engine Shutoff in Parking Lots

2019-04-02
2019-01-0157
1 The efficiency of internal combustion engines remains a research challenge given the mechanical friction and thermodynamic losses. Although incremental engine design changes continue to emerge, the harvesting of waste heat represents an immediate opportunity to address improved energy utilization. An external mobile thermal recovery system for gasoline and diesel engines is proposed for use in parking lots based on phase change material cartridges. Heat is extracted via a retrofitted conduction plate beneath the engine block after engine shutoff. An autonomous robot attaches the cartridge to the plate and transfers the heat from the block to the Phase Change Material (PCM) and returns later to retrieve the packet. These reusable cartridges are then driven to a Heat Extraction and Recycling Tower (HEART) facility where a heat exchanger harvests the thermal energy stored in the cartridges.
Journal Article

An Integrated Cooling System for Hybrid Electric Vehicle Motors: Design and Simulation

2018-04-03
2018-01-1108
Hybrid electric vehicles offer the advantages of reduced emissions and greater travel range in comparison to conventional and electric ground vehicles. Regardless of propulsion strategy, efficient cooling of electric motors remains an open challenge due to the operating cycles and ambient conditions. The onboard thermal management system must remove the generated heat so that the motors and other vehicle components operate within their designed temperature ranges. In this article, an integrated thermal structure, or cradle, is designed to efficiently transfer heat within the motor housing to the end plates for transmission to an external heat exchanger. A radial array of heat pipes function as an efficient thermal connector between the motor and heat connector, or thermal bus, depending on the configuration. Cooling performance has been evaluated for various driving cycles.
Journal Article

A Hybrid Thermal Bus for Ground Vehicles Featuring Parallel Heat Transfer Pathways

2018-04-03
2018-01-1111
Improved propulsion system cooling remains an important challenge in the transportation industry as heat generating components, embedded in ground vehicles, trend toward higher heat fluxes and power requirements. The further minimization of the thermal management system power consumption necessitates the integration of parallel heat rejection strategies to maintain prescribed temperature limits. When properly designed, the cooling solution will offer lower noise, weight, and total volume while improving system durability, reliability, and power efficiency. This study investigates the integration of high thermal conductivity (HTC) materials, carbon fibers, and heat pipes with conventional liquid cooling to create a hybrid “thermal bus” to move the thermal energy from the heat source(s) to the ambient surroundings. The innovative design can transfer heat between the separated heat source(s) and heat sink(s) without sensitivity to gravity.
Technical Paper

Optimization of a Military Ground Vehicle Engine Cooling System Heat Exchanger - Modeling and Size Scaling

2017-03-28
2017-01-0259
Heat rejection in ground vehicle propulsion systems remains a challenge given variations in powertrain configurations, driving cycles, and ambient conditions as well as space constraints and available power budgets. An optimization strategy is proposed for engine radiator geometry size scaling to minimize the cooling system power consumption while satisfying both the heat removal rate requirement and the radiator dimension size limitation. A finite difference method (FDM) based on a heat exchanger model is introduced and utilized in the optimization design. The optimization technique searches for the best radiator core dimension solution over the design space, subject to different constraints. To validate the proposed heat exchanger model and optimization algorithm, a heavy duty military truck engine cooling system is investigated.
Journal Article

Control of a Thermoelectric Cooling System for Vehicle Components and Payloads - Theory and Test

2017-03-28
2017-01-0126
Hybrid vehicle embedded systems and payloads require progressively more accurate and versatile thermal control mechanisms and strategies capable of withstanding harsh environments and increasing power density. The division of the cargo and passenger compartments into convective thermal zones which are independently managed can lead to a manageable temperature control problem. This study investigates the performance of a Peltier-effect thermoelectric zone cooling system to regulate the temperature of target objects (e.g., electronic controllers, auxiliary computer equipment, etc) within ground vehicles. Multiple thermoelectric cooling modules (TEC) are integrated with convective cooling fans to provide chilled air for convective heat transfer from a robust, compact, and solid state device. A series of control strategies have been designed and evaluated to track a prescribed time-varying temperature profile while minimizing power consumption.
Journal Article

A Thermal Bus for Vehicle Cooling Applications - Design and Analysis

2017-03-28
2017-01-0266
Designing an efficient cooling system with low power consumption is of high interest in the automotive engineering community. Heat generated due to the propulsion system and the on-board electronics in ground vehicles must be dissipated to avoid exceeding component temperature limits. In addition, proper thermal management will offer improved system durability and efficiency while providing a flexible, modular, and reduced weight structure. Traditional cooling systems are effective but they typically require high energy consumption which provides motivation for a paradigm shift. This study will examine the integration of passive heat rejection pathways in ground vehicle cooling systems using a “thermal bus”. Potential solutions include heat pipes and composite fibers with high thermal properties and light weight properties to move heat from the source to ambient surroundings.
Journal Article

An Engine Thermal Management System Design for Military Ground Vehicle - Simultaneous Fan, Pump and Valve Control

2016-04-05
2016-01-0310
The pursuit of greater fuel economy in internal combustion engines requires the optimization of all subsystems including thermal management. The reduction of cooling power required by the electromechanical coolant pump, radiator fan(s), and thermal valve demands real time control strategies. To maintain the engine temperature within prescribed limits for different operating conditions, the continual estimation of the heat removal needs and the synergistic operation of the cooling system components must be accomplished. The reductions in thermal management power consumption can be achieved by avoiding unnecessary overcooling efforts which are often accommodated by extreme thermostat valve positions. In this paper, an optimal nonlinear controller for a military M-ATV engine cooling system will be presented. The prescribed engine coolant temperature will be tracked while minimizing the pump, fan(s), and valve power usage.
Technical Paper

A Hybrid Electric Vehicle Thermal Management System - Nonlinear Controller Design

2015-04-14
2015-01-1710
The components in a hybrid electric vehicle (HEV) powertrain include the battery pack, an internal combustion engine, and the electric machines such as motors and possibly a generator. These components generate a considerable amount of heat during driving cycles. A robust thermal management system with advanced controller, designed for temperature tracking, is required for vehicle safety and energy efficiency. In this study, a hybridized mid-size truck for military application is investigated. The paper examines the integration of advanced control algorithms to the cooling system featuring an electric-mechanical compressor, coolant pump and radiator fans. Mathematical models are developed to numerically describe the thermal behavior of these powertrain elements. A series of controllers are designed to effectively manage the battery pack, electric motors, and the internal combustion engine temperatures.
Technical Paper

A Smart Engine Cooling System - Experimental Study of Integrated Actuator Transient Behavior

2015-04-14
2015-01-1604
Smart thermal management systems can positively impact the performance, fuel economy, and reliability of internal combustion engines. Advanced cooling systems typically feature multiple computer controlled actuators - a three way smart valve, a variable speed pump, and a variable speed electric radiator fan(s). To investigate the contributions of these electro-mechanical devices, a scale multifunction test bench was constructed which integrated these actuators, accompanying system sensors, and a controllable engine thermal load with real time data acquisition and control hardware/software. This paper presents a series of experimental studies that focus on the engine's thermal transient response to various actuators input control combinations. The test results established a basis for several key operating conclusions.
Technical Paper

Advanced Thermal Management for Internal Combustion Engines - Valve Design, Component Testing and Block Redesign

2006-04-03
2006-01-1232
Advanced engine cooling systems can enhance the combustion environment, increase fuel efficiency, and reduce tailpipe emissions with less parasitic engine load. The introduction of computer controlled electro-mechanical valves, radiator fans, and coolant pumps require mathematic models and real time algorithms to implement intelligent thermal control strategies for prescribed engine temperature tracking. Smart butterfly valves can replace the traditional wax-based thermostat to control the coolant flow based on both engine temperature and operating conditions. The electric water pump and radiator fan replace the mechanically driven components to reduce unnecessary engine loads at high speeds and provide better cooling at low speeds.
Technical Paper

Modeling and Validation of Automotive “Smart” Thermal Management System Architectures

2004-03-08
2004-01-0048
The functionality and performance of an internal combustion (spark or compression ignition) engine's thermal management system can be significantly enhanced through the application of mechatronics technology. The replacement of the conventional thermostat valve and mechanical coolant pump in the heating/cooling system by a servo-motor driven smart valve and variable flow pump permits powertrain control module regulated coolant flow through the engine block and radiator. In this paper, a dynamic mathematical model will be created for a 4.6L spark ignition engine to analyze various thermal management system architectures. The designs to be studied include the factory configuration, a smart valve upgrade, and the smart valve combined with a variable flow pump and radiator fan. Representative results are presented and discussed to demonstrate improvements in the engine warm-up time, temperature tracking, and component power consumption.
Technical Paper

Smart Thermostat and Coolant Pump Control for Engine Thermal Management Systems

2003-03-03
2003-01-0272
The introduction of mechatronic components into thermal-mechanical systems provides an opportunity to apply real time control strategies for enhanced engine performance. The traditional automotive thermal management system contains the engine, thermostat, air cooled radiator, and centrifugal pump driven by the crankshaft belt. A servo-motor valve and pump may be inserted into the vehicle's heating/cooling system to regulate the coolant flow with the engine control unit. To study these dual actuators, a scale experimental cooling system has been investigated. This automotive inspired thermal system contains a heater, smart thermostat valve, radiator, and variable speed electric pump. A lumped parameter model has been developed to describe the system's behavioral response and establish the basis for temperature regulation. Real time control algorithms are introduced for the synchronous regulation of the valve and pump.
Technical Paper

Coolant Flow Control Strategies for Automotive Thermal Management Systems

2002-03-04
2002-01-0713
The automotive thermal management system is responsible for maintaining engine and passenger compartment temperatures, which promote normal combustion events and passenger comfort. This system traditionally circulates a water ethylene glycol mixture through the engine block using a belt-driven water pump, wax pellet thermostat valve, radiator with electric fan, and heater core. Although vehicle cooling system performance has been reliable and acceptable for many decades, advances in mechatronics have permitted upgrades to powertrain and chassis components. In a similar spirit, the introduction of a variable speed electric water pump and servo-motor thermostat valve allows ECU-based thermal control. This paper examines the integration of an electric water pump and intelligent thermostat valve to satisfy the engine's basic cooling requirements, minimize combustion chamber fluctuations due to engine speed changes, and permit quick heating of a cold block.
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