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Viewing 1 to 30 of 1319
2017-03-28
Technical Paper
2017-01-0215
Mohammad Nahid, Amin Sharfuzzaman, Joydip Saha, Harry Chen, Sadek S. Rahman
More stringent Federal emission regulations and fuel economy requirements have driven the automotive industry toward more sophisticated vehicle thermal management systems to best utilize the waste heat and improve driveline efficiency. The final drive unit in light and heavy duty trucks usually consists of geared transmission and differential housed in a lubricated axle. The automotive rear axles is one of the major sources of power loss in the driveline due to gear friction, churning and bearing loss and have a significant effect on overall vehicle fuel economy. These losses vary significantly with the viscosity of the lubricant. Also the temperatures of the lubricant are critical to the overall axle performance in terms of power losses, fatigue life and wear.
2017-03-28
Technical Paper
2017-01-0216
Joydip Saha, Harshit Coutinho, Sadek S. Rahman
Current and future automotive systems are becoming more complex than ever. They consist of different subsystems such as the engine, transmission, cooling system, driveline, controls systems, HVAC and active/passive safety systems. Hardware and software development for each of these subsystems have different timeline’s. The subsystems are usually developed by different teams within an organization and in some cases are also developed by suppliers. These are some of the main hurdles for carrying out a system level analysis of the vehicle earlier in the development process. Model.CONNECT was used to overcome the above mentioned hurdles by connecting a driveline model, a cooling system model, thermal controller and two-phase flow models with minimal effort.
2017-03-28
Technical Paper
2017-01-0214
Simon O. Omekanda, Rezwanur Rahman, Eric M. Lott, Sadek S. Rahman, Daniel E. Hornback
Designing an efficient transient thermal system model has become a very important task in improving fuel economy. As opposed to steady-state thermal models, part of the difficulty in designing a transient model is optimizing a set of inputs. The first objective in this work is to develop an engine compatible physics-based 1D thermal model for fuel economy and robust control. In order to capture and study the intrinsic thermo-physical nature, both generic “Three Mass” and “Eight Mass” engine model are developed. The models have been correlated heuristically using Simulink and Flowmaster, respectively. In order to extend the lumped mass engine model it also has been extended to Simulink model. In contrast to the complexity of the models the “Heuristic search” of input parameters has been found to be challenging and time consuming.
2017-03-28
Technical Paper
2017-01-0212
Mohammad Nahid, Rezwanur Rahman, Tabassum Hossainy, Shreyas Kapatral, Prashant Modi, Joydip Saha, Sadek S. Rahman
More stringent Federal emission regulations and fuel economy requirements have driven the automotive industry toward more efficient vehicle thermal management systems to best utilize the heat produced from burning fuel and improve driveline efficiency. The greatest part of the effort is directed toward the hybridization of automotive transmission systems. The efficiency and durability of hybrid powertrain depends on the heat generation in electric motors and their interactions among each other, ambient condition, the cooling system and the transmission component configuration. These increase the complexity of motor temperature prediction as well as the computational cost of running a conjugate heat-transfer based CFD analysis. In this paper, 1-D physics based thermal model is developed which allows rapid and accurate component-wise temperature estimation of the electric motor as well as transmission lubricant temperature during both steady-state and transient driving cycles.
2017-03-28
Technical Paper
2017-01-0016
Don Zaremba, Emily Linehan, Carlos Ramirez Ramos
Abstract For over thirty years, the silicon power MOSFET’s role has expanded from a few key components in electronic engine control to a key component in nearly every automotive electronics system. New and emerging automotive applications such as 48 V micro hybrids and autonomous vehicle operation require improved power MOSFET performance. This paper reviews mature and state of the art power MOSFET technologies, from planar to shield gate trench, with emphasis on applicability to automotive electronic systems. The automotive application environment presents unique challenges for electronic systems and associated components such as potential for direct short to high capacity battery, high voltage battery transients, high ambient temperature, electromagnetic interference (EMI) limitations, and large delta temperature power cycling. Moreover, high reliability performance of semiconductor components is mandatory; sub 1 ppm overall failure rate is now a fundamental requirement.
2017-03-28
Technical Paper
2017-01-0633
Kurt Stuart, Terry Yan, James Mathias
In the interest of improving the efficiency of the internal combustion engine, many alternatives to the traditional 4-stroke engine have been proposed. One promising alternative is the 5-stroke engine, which adds an additional expansion stroke to the traditional 4-stroke engine. By adding an additional expansion stroke, the combustion gas can be further expanded with increased work output for the same heat input. The extra expansion stroke, i.e. the 5th stroke, is accomplished in a separate cylinder operating on a 2 stroke cycle. This can be readily accomplished by adding one expansion cylinder with two combustion cylinders operating 360 degree off-phase, creating an engine with 3 cylinders. Previous works have investigated the interactions of the engines operating points and design parameters. Few have, however, included in-cylinder heat transfer and mass lost due to blow-by, which can have a significant effect on the thermodynamic performance of such an engine.
2017-03-28
Technical Paper
2017-01-0937
David Culbertson, James Pradun, Magdi Khair, Jeff Diestelmeier
Abstract Tightening regulations throughout the world demand a reduction in fuel consumption and NOX emission levels, creating an increasing need for additional heat for SCR aftertreatment. A durable and low cost heating system is needed for vehicles with hybrid or 24Vdc electricity. Recent development efforts have resulted in much smaller and lower cost heating systems for electrical systems ranging from 400 to 24Vdc. Test results demonstrate the feasibility of reducing the size of the heater and the relationship of heater power to the amount of time required to heat the exhaust. Intelligent solid state switching enables the heater to be smaller without compromising durability.
2017-03-28
Technical Paper
2017-01-1207
Satyam Panchal, Scott Mathewson, Roydon Fraser, Richard Culham, Michael Fowler
Abstract Lithium-ion batteries, which are nowadays common in laptops, cell phones, toys, and other portable electronic devices, are also viewed as a most promising advanced technology for electric and hybrid electric vehicles (EVs and HEVs), but battery manufacturers and automakers must understand the performance of these batteries when they are scaled up to the large sizes needed for the propulsion of the vehicle. In addition, accurate thermo-physical property input is crucial to thermal modeling. Therefore, a designer must study the thermal characteristics of batteries for improvement in the design of a thermal management system and also for thermal modeling. This work presents a purely experimental thermal characterization in terms of measurement of the temperature gradient and temperature response of a lithium-ion battery utilizing a promising electrode material, LiFePO4, in a prismatic pouch configuration.
2017-03-28
Technical Paper
2017-01-1217
Jiangong Zhu, Zechang Sun, Xuezhe Wei, Haifeng Dai
Abstract An alternating current (AC) heating method for a NMC lithium-ion battery with 8Ah capacity is proposed. The effects of excitation frequency, current amplitudes, and voltage limit condition on the temperature evolution are investigated experimentally. Current amplitudes are set to 24A(3C), 40(5C), and 64A(8C), and excitation frequencies are set to 300Hz, 100Hz, 30Hz, 10Hz, 5Hz, and 1Hz respectively. The voltage limitations are necessary to protect cells from overcharge and over-discharge. Therefore the voltage limit condition (4.2V/2.75V, 4.3V/2.65V, and 4.4V/2.55V) are also considered in depth to verify the feasibility of the AC heating method. The temperature rises prominently as the current increases, and the decrement of frequencies also lead to the obvious growth of battery temperature. The battery obtain the maximum temperature rise at 64A and 1Hz, which takes 1800s to heat up the battery from -25°C to 18°C.
2017-03-28
Technical Paper
2017-01-0513
Jose Serrano, Luis Miguel García-Cuevas lng, Andres Tiseira, Tatiana Rodriguez Usaquen, Guillaume Mijotte
Abstract The growing concerns about emissions in internal combustion engines, makes necessary a good prediction of the after-treatment inlet temperature in fast one-dimensional engine simulation codes. Different simple models have been developed during the last years which improve the prediction of the turbocharger heat transfer phenomena. Although these models produce good results when computing the turbine outlet temperature, those models focus on the axial heat transfer paths and lack the capability of producing detailed results about the internal thermal behavior of the turbocharger. In this work, a new version of heat transfer model for automotive turbochargers is presented. This model discretizes the turbocharger in both the radial and axial directions, and computes the heat transfer and temperature at different parts of the machine.
2017-03-28
Technical Paper
2017-01-0521
Richard Merrett, John Murray, Doug Kolak
Abstract The development of experimental ORC systems is an extremely complex, time consuming and costly task. Running a range of experiments on a number of different component configurations may be prohibitively expensive and subject to equipment issues and failures. Yet ORC systems offer significant potential for automotive manufacturers to improve vehicle efficiency, reduce fuel consumption and vehicle emissions; the technology is particularly relevant for those involved in the design and/or manufacture of heavy duty trucks. This paper is focused on the validation of a computational ORC system simulation tool against a number of SAE published test results based on the European Stationary Cycle. Such studies on industry standard systems are essential in order to help promote confidence in a virtual prototype approach.
2017-03-28
Technical Paper
2017-01-0527
Arya Yazdani, Jeffrey Naber, Mahdi Shahbakhti, Paul Dice, Chris Glugla, Stephen Cooper, Douglas McEwan, Garlan Huberts
An accurate estimation of cycle-by-cycle in-cylinder mass and the composition of the cylinder charge is required for spark-ignition engine transient control strategies to obtain required torque, Air-Fuel-Ratio (AFR) and meet engine pollution regulations. Mass Air Flow (MAF) and Manifold Absolute Pressure (MAP) sensors have been utilized in different control strategies to achieve these targets; however, these sensors have response delay in transients. As an alternative to air flow metering, in-cylinder pressure sensors can be utilized to directly measure cylinder pressure, based on which, the amount of air charge can be estimated without the requirement to model the dynamics of the manifold.
2017-03-28
Technical Paper
2017-01-0526
Oldrich Vitek, Jan Macek
Abstract The proposed paper deals with thermodynamic optimization of highly flexible ICE (variable compression ratio, intake/exhaust VVA) while comparing e-turbocharging concept with classical one. The e-turbocharging approach is based on idea that compressor/turbine has its own electric machine (motor/generator) and that additional electric energy can be supplied/attached from/to engine crank train. Hence it allows independent control of compressor/turbine. On the other hand, classical approach is based on a standard mechanical connection between turbine and compressor. The whole system (flexible engine + boost device) is optimized under steady operation – low load (BMEP of 4 bar), medium load (BMEP of 13 bar), high load (BMEP of 30, 25 and 18 bar) and maximum load are considered. Moreover, 3 combustion concepts are considered – classical SI and CI, and ideal RCCI.
2017-03-28
Technical Paper
2017-01-0627
Bo Yang, Peter Woyciesjes, Aleksei Gershun
Abstract In this paper, new test results in the use of electrochemical techniques to measure corrosion in extended life engine coolants are presented. Corrosion protection performance of the engine coolants (including both fresh coolants and simulated used coolants) for typical cooling system metals under heat rejecting and heat accepting surface corrosion conditions for both general corrosion and localized corrosion are measured under conditions similar to the ones encountered in vehicle engine cooling systems as a function of immersion time. Fleet tests of the coolants were also conducted. They are used to provide support on the electrochemical test methodologies adopted. The effective use of electrochemical techniques to aid the development of the next generation of extended life coolant technologies with improved corrosion protection performance and a longer service life will be demonstrated and discussed.
2017-03-28
Technical Paper
2017-01-0624
Jiaxin Liu, Sicheng Qin, Yankun Jiang, Shumo He
Abstract In this work, a XD132 Road Roller from XCMG in China was employed as a research basis to study the heat exchange performance of the heat dissipation module under varied working conditions. The module in the XD132 consists of a cooling fan and three radiators. At first, the numerical investigation on the elementary units of radiators was performed to obtain Colburn j factor and Fanning friction f factor, which were used for the ε-NTU method to predict the radiator performance. The fan was numerically tested in a wind test tunnel to acquire the performance curve. The performance data from both investigations were transformed into the boundary conditions of the numerical vehicle model in a virtual tunnel. A field experiment was carried out to validate the simulation accuracy, and an entrance coefficient was proposed to discuss the performance regularity under four working conditions.
2017-03-28
Technical Paper
2017-01-0634
Schoeffmann Wolfgang, Helfried Sorger, Siegfried Loesch, Wolfgang Unzeitig, Thomas Huettner, Alois Fuerhapter
Abstract In order to achieve future CO2 targets - in particular under real driving conditions - different powertrain technologies will have to be introduced. Beside the increasing electrification of the powertrain, it will be essential to utilize the full potential of the internal combustion engine. In addition to further optimization of the combustion processes and the reduction of mechanical losses in the thermal- and energetic systems, the introduction of Variable Compression Ratio (VCR) is probably the measure with the highest potential for fuel economy improvement. VCR systems are expected to be introduced to a considerable number of next generation turbocharged Spark Ignited (SI) engines in certain vehicle classes. The basic principle of the AVL VCR system described in this paper is a 2-stage variation of the conrod length and thus the Compression Ratio (CR).
2017-03-28
Technical Paper
2017-01-0631
David C. Ogbuaku, Timothy Potter, James M. Boileau
Abstract The need to increase the fuel-efficiency of modern vehicles while lowering the emission footprint is a continuous driver in automotive design. This has given rise to the use of engines with smaller displacements and higher power outputs. Compared to past engine designs, this combination generates greater amounts of excess heat which must be removed to ensure the durability of the engine. This has resulted in an increase in the number and size of the heat exchangers required to adequately cool the engine. Further, the use of smaller, more aerodynamic front-end designs has reduced the area available in the engine compartment to mount the heat exchangers. This is an issue, since the reduced engine compartment space is increasingly incapable of supporting an enlarged rectangular radiator system.
2017-03-28
Technical Paper
2017-01-0629
John Kuo, George Garfinkel
Abstract Thermal modeling of liquid-cooled vehicle traction battery assemblies using Computational Fluid Dynamics (CFD) usually involves large models to accurately resolve small cooling channel details, and intensive computation to simulate drive-cycle transient solutions. This paper proposes a segregated method to divide the system into three parts: the cells, the cold plate and the interface between them. Each of the three parts can be separated and thermally characterized and then combined to predict the overall system thermal behavior for both steady-state and transient operating conditions. The method largely simplifies battery thermal analysis to overcome the limitations of using large 3D CFD models especially for pack level dynamic drive cycle simulations.
2017-03-28
Technical Paper
2017-01-0620
Chandrakant Parmar, Sethuramalingam Tyagarajan, Sashikant Tiwari, Ravindra Thonge, S Arun Paul
Abstract The engine compartment of passenger car application contains various source which radiates the produced heat and raises the temperature level of the compartment. The rise in compartment temperature increases the body temperature of individual component. The rise in body temperature of critical components can endanger the durability or functionality of the specific component or a system in which it operates. The aim of this paper is to strategize thermal protection of the rear mounted engine and its components of a vehicle having radiator and cooling fan mounted in front. An additional ventilation fan with speed sensor is fitted alongside rear mounted engine and a unique monitoring technique framed in the EMS ECU to protect critical components like HT cables, alternators, ECUs, wiring harness etc. from thermal damage. The EMS continuously monitors the engine speed, vehicle speed and the PWM signal of ventilation fan to ensure the intended operation of the ventilation fan.
2017-03-28
Technical Paper
2017-01-0730
Jose M Desantes, J. Javier Lopez, Jose M Garcia-Oliver, Dario Lopez-Pintor
Abstract In this work, a 5-zone model has been applied to replicate the in-cylinder conditions evolution of a Rapid Compression-Expansion Machine (RCEM) in order to improve the chemical kinetic analyses by obtaining more accurate simulation results. To do so, CFD simulations under motoring conditions have been performed in order to identify the proper number of zones and their relative volume, walls surface and temperature. Furthermore, experiments have been carried out in an RCEM with different Primary Reference Fuels (PRF) blends under homogeneous conditions to obtain a database of ignition delays and in-cylinder pressure and temperature evolution profiles. Such experiments have been replicated in CHEMKIN by imposing the heat losses and volume profiles of the experimental facility using a 0-D 1-zone model. Then, the 5-zone model has been analogously solved and both results have been compared to the experimental ones.
2017-03-28
Technical Paper
2017-01-1737
Piyapong Premvaranon, Jenwit Soparat, Apichart Teralapsuwan, Sutee Olarnrithinun
Abstract Beyond the modern design and illumination quality of automotive lamps, thermal management plays a crucial role and must be fulfilled in the early stages of the design process. An excessive thermal radiation from incandescent bulb can cause a severe thermal degradation of plastic parts such as housing or optical lens. Hence, to assess such impact of heat on the plastic parts, thermal analysis of a license plate lamp was investigated by a proposed technique combining computational fluid dynamics (CFD) and ray tracing mapping method. Then, the accuracy and computational cost of the method were compared with thermal results obtained by a thermal radiation model using Monte Carlo (MC) technique for calculating radiation effect coupled with CFD in heat transfer analysis. Finally, a comparison of temperature results from both techniques were validated with practical thermal measurements of license plate lamp prototype.
2017-03-28
Journal Article
2017-01-0388
Haeyoon Jung, MiYeon Song, Sanghak Kim
This paper proposes the Off-cycle credit alternative test methodology for Semi-transparent solar panel integrated on Automobile roof glass to achieve the CO2 credits from the Environmental Protection Agency (EPA) & the National Highway Traffic Safety Administration (NHTSA). Manufactures offer the option to put solar cells on the roof of a vehicle for reducing cabin ambient temperature. However, Hyundai Motors develops the semi-transparent solar roof with a controller to provide electric energy for vehicles. This electrical energy cannot be accounted for on the current EPA cycles either the two cycle test or the five-cycle test. Therefore, the manufacture has to establish the methodology based on solar system for vehicles. In order to improve the efficiency of our solar system and to calculate reduced CO2 emission, we studied useable solar energy in driving condition other than peak power in standard test condition(@ 25℃, 1Sun).
2017-03-28
Journal Article
2017-01-0266
Shervin Shoai Naini, Junkui (Allen) Huang, Richard Miller, John R. Wagner, Denise Rizzo, Scott Shurin, Katherine Sebeck
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 peak component heat loads. 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.
2017-03-28
Journal Article
2017-01-0622
Sury Janarthanam, Sarav Paramasivam, Patrick Maguire, James Gebbie, Douglas Hughes
Abstract Hybrid Electric Vehicles (HEV) utilize a High Voltage (HV) battery pack to improve fuel economy by maximizing the capture of vehicle kinetic energy for reuse. Consequently, these HV battery packs experience frequent and rapid charge-discharge cycles. The heat generated during these cycles must be managed effectively to maintain battery cell performance and cell life. The HV battery pack cooling system must keep the HV battery pack temperature below a design target value and maintain a uniform temperature across all of the cells in the HV battery pack. Herein, the authors discuss some of the design points of the air cooled HV battery packs in Ford Motor Company’s current model C-Max and Fusion HEVs. In these vehicles, the flow of battery cooling air was required to not only provide effective cooling of the battery cells, but to simultaneously cool a direct current high voltage to low voltage (DC-DC) converter module.
2017-03-28
Journal Article
2017-01-0625
Yen-Chung Liu, Brian Sangeorzan, Alex Alkidas
Abstract The purpose of this research was to measure and correlate the area-average heat transfer coefficients for free, circular upward-impinging oil-jets onto two automotive pistons having different undercrown shapes and different diameters. For the piston heat transfer studies, two empirical area-average Nusselt number correlations were developed. One was based on the whole piston undercrown surface area with the Nusselt number based on the nozzle diameter, and the other was based on the oil-jet impingement area with the Nusselt number based on the oil-jet effective impingement diameter. The correlations can predict the 95% and 94% of the experimental measurements within 30% error, respectively. The first correlation is simpler to use and can be employed for cases in which the oil jet wets the whole piston undercrown. The latter may be more useful for larger pistons or higher Prandtl number conditions in which the oil jet wets only a portion of the undercrown.
2017-03-28
Journal Article
2017-01-0722
Pablo Olmeda, Jaime Martin, Antonio Garcia, David Villalta, Alok Warey, Vicent Domenech
Abstract Growing awareness about CO2 emissions and their environmental implications are leading to an increase in the importance of thermal efficiency as criteria to design internal combustion engines (ICE). Heat transfer to the combustion chamber walls contributes to a decrease in the indicated efficiency. A strategy explored in this study to mitigate this efficiency loss is to promote low swirl conditions in the combustion chamber by using low swirl ratios. A decrease in swirl ratio leads to a reduction in heat transfer, but unfortunately, it can also lead to worsening of combustion development and a decrease in the gross indicated efficiency. Moreover, pumping work plays also an important role due to the effect of reduced intake restriction to generate the swirl motion. Current research evaluates the effect of a dedicated injection strategy to enhance combustion process when low swirl is used.
2017-03-28
Technical Paper
2017-01-0732
Stijn Broekaert, Thomas De Cuyper, Michel De Paepe, Sebastian Verhelst
Abstract Homogeneous Charge Compression Ignition (HCCI) engines can achieve both a high thermal efficiency and near-zero emissions of NOx and soot. However, their maximum attainable load is limited by the occurrence of a ringing combustion. At high loads, the fast combustion rate gives rise to pressure oscillations in the combustion chamber accompanied by a ringing or knocking sound. In this work, it is investigated how these pressure oscillations affect the in-cylinder heat transfer and what the best approach is to model the heat transfer during ringing combustion. The heat transfer is measured with a thermopile heat flux sensor inside a CFR engine converted to HCCI operation. A variation of the mass fuel rate at different compression ratios is performed to measure the heat transfer during three different operating conditions: no, light and severe ringing. The occurrence of ringing increases both the peak heat flux and the total heat loss.
2017-03-28
Journal Article
2017-01-0011
Kesav Kumar Sridharan, Swaminathan Viswanathan
Abstract Current generation automobiles are controlled by electronic modules for performing various functions. These electronic modules have numerous semiconductor devices mounted on printed circuit boards. Solders are generally used as thermal interface material between surface mount devices and printed circuit boards (PCB) for efficient heat transfer. In the manufacturing stage, voids are formed in solders during reflow process due to outgassing phenomenon. The presence of these voids in solder for power packages with exposed pads impedes heat flow and can increase the device temperature. Therefore it is imperative to understand the effect of solder voids on thermal characteristics of semiconductor devices. But the solder void pattern will vary drastically during mass manufacturing. Replicating the exact solder void pattern and doing detail simulation to predict the device temperature for each manufactured module is not practical.
2017-03-28
Journal Article
2017-01-0126
Joshua W. Finn, John R. Wagner
Abstract 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.
2017-03-28
Journal Article
2017-01-1215
Peter Haussmann, Joachim Melbert
Abstract Battery safety is the most critical requirement for the energy storage systems in hybrid and electric vehicles. The allowable battery temperature is limited with respect to the battery chemistry in order to avoid the risk of thermal runaway. Battery temperature monitoring is already implemented in electric vehicles, however only cell surface temperature can be measured at reasonable cost using conventional sensors. The internal cell temperature may exceed the surface temperature significantly at high current due to the finite internal electrical and thermal cell resistance. In this work, a novel approach for internal cell temperature measurement is proposed applying on board impedance spectroscopy. The method considers the temperature coefficient of the complex internal cell impedance. It can be observed by current and voltage measurements as usually performed by standard battery management systems.
Viewing 1 to 30 of 1319

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