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Viewing 151 to 180 of 10344
2016-04-05
Technical Paper
2016-01-0283
Joydip Saha, Harry Chen, Sadek Rahman
Abstract More stringent federal emission regulations and fuel economy requirements have driven the automotive industry toward more sophisticated vehicle thermal management systems in order to best utilize the waste heat and minimize overall power consumption. With all new technologies and requirements, how to properly design, optimize, and control the vehicle thermal and cooling systems become great challenges to automotive engineers. Model based approach has become essential to the new thermal management system architectures design and evaluation of the optimal system solutions. This paper will discuss how the model based vehicle thermal system simulation tools have been developed from analytical & empirical data, and have been used for assessment and development of new thermal management system architectures.
2016-04-05
Technical Paper
2016-01-1512
Jeya Padmanaban, Roger Burnett, Andrew Levitt
Abstract This paper updates the findings of prior research addressing the relationship between seatback strength and likelihood of serious injury/fatality to belted drivers and rear seat occupants in rear-impact crashes. Statistical analyses were performed using 1995-2014 CY police-reported crash data from seventeen states. Seatback strength for over 100 vehicle model groupings (model years 1996-2013) was included in the analysis. Seatback strength is measured in terms of the maximum moment that results in 10 inches of seat displacement. These measurements range from 5,989 in-lbs to 39,918 in-lbs, resulting in a wide range of seatback strengths. Additional analysis was done to see whether Seat Integrated Restraint Systems (SIRS) perform better than conventional belts in reducing driver and rear seat occupant injury in rear impacts. Field data shows the severe injury rate for belted drivers in rear-impact crashes is less than 1%.
2016-04-05
Journal Article
2016-01-0261
Lili Feng, Predrag Hrnjak
Abstract This paper presents a simulation model for a reversible air conditioning and heat pump system for electric vehicles. The system contains a variable speed compressor, three microchannel heat exchangers, an accumulator, and two electronic expansion valves. Heat exchangers are solved by discretizing into cells. Compressor and accumulator models are developed by fitting data with physical insights. Expansion valves are modeled by isenthalpic processes. System performance is calculated by connecting all parts in the same way as the physical system and solved iteratively. The model is reasonably validated against experimental data from a separate experimental study. Future improvement is needed to take into account maldistribution in outdoor heat exchanger working as an evaporator in HP mode. Charge retention in components also requires further study.
2016-04-05
Technical Paper
2016-01-0213
Andrea Alessandro Piovano, Laura Maria Lorefice, Giuseppe Scantamburlo
Abstract The aim of this work has been to develop an advanced methodology to model the car cabin cool down test. It has been decided to focus the attention on the fluid dynamics and thermal dynamics aspects of the phenomenon, trying to catch the correct heat transfer between the outside environment and the internal cabin with a thermal tool, together with an internal flows CFD simulation. To start with, an experimental cool down test was conducted in the FCA Italy climatic wind tunnel on a L0 segment vehicle, to get the correlation data and the boundary conditions required for the simulation: panel ducts air transient temperatures, wind tunnel air temperature and velocity, solar array load. The simulation was divided into two steps: steady state soak with a finite difference based thermal solver and transient cool down, coupling the thermal solver with a CFD one. In particular an advanced CFD/thermal coupled approach has been applied, using STAR-CCM+® and TAITherm® tools.
2016-04-05
Technical Paper
2016-01-1410
Stefan G. Grötsch, Morten Brink, Roland Fiederling, Thomas Liebetrau, Ingo Möllers, Jörg Moisel, Hermann Oppermann, Alexander Pfeuffer
Abstract A cooperation of several research partners supported by the German Federal Ministry of Research and Education proposes a new active matrix LED light source. A multi pixel flip chip LED array is directly mounted to an active driver IC. A total of 1024 pixel can be individually addressed through a serial data bus. Several of these units are integrated in a prototype headlamp to enable advanced light distribution patterns in an evaluation vehicle.
2016-04-05
Technical Paper
2016-01-0212
Paras Kaushal, Satishchandra C. Wani
Abstract TeamIndus is the only Indian participant in the Google Lunar X Prize (GLXP). GLXP, also referred to as Moon 2.0, is an inducement prize space competition organized by the X Prize Foundation, and sponsored by Google. The mission objective is to soft land a rover on moon, travel 500 meters and transmit HD videos and images to Earth. Team Indus’s strategy is to design and realize a lunar lander that will deliver a rover on to the surface of the moon which will accomplish GLXP mission objectives. The mission configuration comprises of four phases- Earth orbits, moon orbits, descent and surface operations. The lander during its interplanetary journey from earth to moon is exposed to different thermal loads viz. solar load, earth IR and albedo, moon IR and albedo, cold space at 4K and eclipse periods. The lander is also exposed to high temperatures of thruster nozzle during orbital transfer maneuvers.
2016-04-05
Journal Article
2016-01-1402
Jeffrey Hurlbut, Daniel Cashen, Emily Robb, Lora L. Spangler, Jim Eckhart
Abstract Head-up display (HUD) technology creates inherent driver safety advantages by displaying critical information directly in the driver’s line of sight, reducing eyes off road and accommodation time. This is accomplished using a system of relay optics and windshield reflection to generate a virtual image that appears to hover over the hood near the bumper. The windshield is an integral optical component of the HUD system, but unfortunately the windshield-air interface causes a double image ghost effect as a result of refractive index change, reducing HUD image clarity. Current technology uses a constant angle wedged PVB windshield interlayer to eliminate double image at a single driver height. However, the HUD double image persists for all other viewing locations. Eastman Chemical Company has developed a new interlayer technology which eliminates the double image at all driver locations by tuning the wedge angle as a function of driver occupant seated height.
2016-04-05
Journal Article
2016-01-0202
Bjoern Franzke, Stefan Pischinger, Philipp Adomeit, Christof Schernus, Johannes Scharf, Tolga Uhlmann
Abstract A new approach is presented to modelling wall heat transfer in the exhaust port and manifold within 1D gas exchange simulation to ensure a precise calculation of thermal exhaust enthalpy. One of the principal characteristics of this approach is the partition of the exhaust process in a blow-down and a push-out phase. In addition to the split in two phases, the exhaust system is divided into several sections to consider changes in heat transfer characteristics downstream the exhaust valves. Principally, the convective heat transfer is described by the characteristic numbers of Nusselt, Reynolds and Prandtl. However, the phase individual correlation coefficients are derived from 3D CFD investigations of the flow in the exhaust system combined with Low-Re turbulence modelling. Furthermore, heat losses on the valve and the seat ring surfaces are considered by an empirical model approach.
2016-04-05
Technical Paper
2016-01-0184
Toshio Murata, Tadashi Nakagawa, Hisashi Nishino, Kazunari Matsuura
In order to speed up engine coolant warm-up, the exhaust heat recirculation system collects and reuses the heat from exhaust gases by utilizing the heat exchanger. The conventional system improves actual fuel economy at the scene of the engine restart in winter season only. The heat recirculation system becomes more effective at the low outside temperature because it takes longer time to warm up engine coolant. However, the heat recirculation system becomes less effective at the high outside temperature because it takes shorter time to warm up engine coolant. Therefore, the new exhaust heat recirculation system is developed, which adopted as follows: 1) a fin-type heat exchanger in order to enhance exhaust recirculation efficiency 2) a thinner heat exchanger component and smaller amount of engine coolant capacity in the heat exchanger in order to reduce the heat mass As a result, the actual fuel economy is more improved in winter season.
2016-04-05
Journal Article
2016-01-0186
Hyunki Sul, Taehoon Han, Mitchell Bieniek, John Hoard, Chih-Kuang Kuan, Daniel Styles
Abstract Exhaust gas recirculation (EGR) coolers are used on diesel engines to reduce peak in-cylinder flame temperatures, leading to less NOx formation during the combustion process. There is an ongoing concern with soot and hydrocarbon fouling inside the cold surface of the cooler. The fouling layer reduces the heat transfer efficiency and causes pressure drop to increase across the cooler. A number of experimental studies have demonstrated that the fouling layer tends to asymptotically approach a critical height, after which the layer growth ceases. One potential explanation for this behavior is the removal mechanism derived by the shear force applied on the soot and hydrocarbon deposit surface. As the deposit layer thickens, shear force applied on the fouling surface increases due to the flow velocity growth. When a critical shear force is applied, deposit particles start to get removed.
2016-04-05
Journal Article
2016-01-0183
Taehoon Han, Hyunki Sul, John Hoard, Chih-Kuang Kuan, Daniel Styles
Abstract Exhaust Gas Recirculation (EGR) coolers are commonly used in diesel and modern gasoline engines to reduce the re-circulated gas temperature. A common problem with the EGR cooler is a reduction of the effectiveness due to the fouling layer primarily caused by thermophoresis, diffusion, and hydrocarbon condensation. Typically, effectiveness decreases rapidly at first, and asymptotically stabilizes over time. There are several hypotheses of this stabilizing phenomenon; one of the possible theories is a deposit removal mechanism. Verifying such a mechanism and finding out the correlation between the removal and stabilization tendency would be a key factor to understand and overcome the problem. Some authors have proposed that the removal is a possible influential factor, while other authors suggest that removal is not a significant factor under realistic conditions.
2016-04-05
Technical Paper
2016-01-0224
Robin Y. Cash, Edward Lumsdaine, Apoorv Talekar, Bashar AbdulNour
Abstract To address the need of increasing fuel economy requirements, automotive Original Equipment Manufacturers (OEMs) are increasing the number of turbocharged engines in their powertrain line-ups. The turbine-driven technology uses a forced induction device, which increases engine performance by increasing the density of the air charge being drawn into the cylinder. Denser air allows more fuel to be introduced into the combustion chamber, thus increasing engine performance. During the inlet air compression process, the air is heated to temperatures that can result in pre-ignition resulting and reduced engine functionality. The introduction of the charge air cooler (CAC) is therefore, necessary to extract heat created during the compression process. The present research describes the physics and develops the optimized simulation method that defines the process and gives insight into the development of CACs.
2016-04-05
Technical Paper
2016-01-0219
Song Lan, Zhijia Yang, Richard Stobart, Edward Winward
Abstract An automotive engine can be more efficient if thermoelectric generators (TEG) are used to convert a portion of the exhaust gas enthalpy into electricity. Due to the relatively low cost of the incoming thermal energy, the efficiency of the TEG is not an overriding consideration. Instead, the maximum power output (MPO) is the first priority. The MPO of the TEG is closely related to not only the thermoelectric materials properties, but also the operating conditions. This study shows the development of a numerical TEG model integrated with a plate-fin heat exchanger, which is designed for automotive waste heat recovery (WHR) in the exhaust gas recirculation (EGR) path in a diesel engine. This model takes into account the following factors: the exhaust gas properties’ variation along the flow direction, temperature influence on the thermoelectric materials, thermal contact effect, and heat transfer leakage effect. Its accuracy has been checked using engine test data.
2016-04-05
Journal Article
2016-01-0215
Amey Y. Karnik, Adrian Fuxman, Phillip Bonkoski, Mrdjan Jankovic, Jaroslav Pekar
Abstract An advanced powertrain cooling system with appropriate control strategy and active actuators allows greater flexibility in managing engine temperatures and operating near constraints. An organized controls development process is necessary to allow comparison of multiple configurations to select the best way forward. In this work, we formulate, calibrate and validate a Model Predictive Controller (MPC) for temperature regulation and constraint handling in an advanced cooling system. A model-based development process was followed; where the system model was used to develop and calibrate a gain scheduled linear MPC. The implementation of MPC for continuous systems and the modification related to implementing switching systems has been described. Multiple hardware configurations were compared with their corresponding control system in simulations.
2016-04-05
Technical Paper
2016-01-0206
Ken T. Lan
An Air intake system (AIS) is a duct system which leads the airflow going into the internal combustion engine. Combustion requires oxygen, and the more oxygen is provided into the combustion process the more power it will produce. The lower the air temperature, the higher its density, and hence there is more oxygen in a unit volume. The quality of air entering engine can be measured with the air temperature. AIS design and routing influence the air charge temperature (ACT) at intake manifold runners and ACT is normally measured at AIS throttle body in reality. Higher ACT lead to inefficient combustion and can lead to spark retard. Optimization of AIS designs and reduction of ACT can improve engine performance and vehicle fuel economy. High ACT can be a result of two different phenomena: Recirculation - Hot air from the underhood environment ingested into the dirty side of the air intake system.
2016-04-05
Journal Article
2016-01-0233
Masayoshi Mori, Manabu Matsumoto, Makoto Ohtani
Abstract The practical application of heat recovery using thermoelectrics requires the realization of reasonable cost effectiveness. Therefore, a thermoelectric generator (TEG) structure that can compatibly increase efficiency and reduce cost was investigated with the aim of enhancing cost effectiveness. To increase efficiency, a method of using a vacuum space structure to reduce the TEG size was investigated to enable installation just after the close-coupled catalyzer, which is subject to many space restrictions. It was found that by making it possible to use high temperature exhaust heat, power generation efficiency can be increased to approximately twice that of the typical under floor installation. In addition, coupled simulation of heat transfer and power generation using FEM, 1D cost effectiveness simulations, and bench tests were performed with the aim of reducing cost.
2016-04-05
Technical Paper
2016-01-0651
Masaki Harada, Takashi Yasuda, Shota Terachi, Sergio Pujols, Jason R. Spenny
Abstract Due to the recent trend emphasizing on environmental friendly, engine supercharger downsizing technology has been under development globally. In this report, the technical knowledge for high performance and high quality water-cooled CAC development is provided. For higher cooling performance, the optimum fin and tube core matrix water-cooled CAC, delivering best performance and quality have been developed. For higher reliability against thermal stress, the detail specifications of water-cooled CAC based on the transient analysis and the simulation technology have been established.
2016-04-05
Technical Paper
2016-01-0646
Pablo Olmeda, Jaime Martin, Antonio Garcia, Diego Blanco, Alok Warey, Vicent Domenech
Abstract Regulated emissions and fuel consumption are the main constraints affecting internal combustion engine (ICE) design. Over the years, many techniques have been used with the aim of meeting these limitations. In particular, exhaust gas recirculation (EGR) has proved to be an invaluable solution to reduce NOx emissions in Diesel engines, becoming a widely used technique in production engines. However, its application has a direct effect on fuel consumption due to both the changes in the in-cylinder processes, affecting indicated efficiency, and also on the air management. An analysis, based on the engine Global Energy Balance, is presented to thoroughly assess the behavior of a HSDI Diesel engine under variable EGR conditions at different operating points. The tests have been carried out keeping constant the conditions at the IVC and the combustion centering.
2016-04-05
Journal Article
2016-01-0661
Yoshifumi Wakisaka, Minaji Inayoshi, Kenji Fukui, Hidemasa Kosaka, Yoshihiro Hotta, Akio Kawaguchi, Noriyuki Takada
The reduction of the heat loss from the in-cylinder gas to the combustion chamber wall is one of the key technologies for improving the thermal efficiency of internal combustion engines. This paper describes an experimental verification of the “temperature swing” insulation concept, whereby the surface temperature of the combustion chamber wall follows that of the transient gas. First, we focus on the development of “temperature swing” insulation materials and structures with the thermo-physical properties of low thermal conductivity and low volumetric heat capacity. Heat flux measurements for the developed insulation coating show that a new insulation material formed from silica-reinforced porous anodized aluminum (SiRPA) offers both heat-rejecting properties and reliability in an internal combustion engine. Furthermore, a laser-induced phosphorescence technique was used to verify the temporal changes in the surface temperature of the developed insulation coating.
2016-04-05
Technical Paper
2016-01-0664
Ahmed E. Hassaneen, Wael I. A. Aly, Gamal Bedair, Mohammed Abdussalam
Abstract The thermal performance of an ammonia-water-hydrogen absorption refrigeration system using the waste exhaust gases of an internal combustion diesel engine as energy source was investigated experimentally. An automotive engine was tested in a bench test dynamometer, with the absorption refrigeration system adapted to the exhaust pipe via a heat exchanger. The engine was tested for different torques (15 N.m, 30 N.m, and 45 N.m). The exhaust gas flow to the heat exchanger built on the generator was controlled manually using two control valves. The refrigerator reached a steady state temperature between 10 and 14.5°C about 3.5 hours after system start up, depending on engine load. The maximum coefficient of performance was 0.10 obtained for the controlled exhaust mass flow case at torque 30 Nm after 3hrs from system startup.
2016-04-05
Technical Paper
2016-01-0681
Cyrille Constensou, Vincent Collee
Abstract Increasing the efficiency of internal combustion engines is mandatory to meet ever more stringent regulations. The implementation of very high compression ratio (> 15:1) is the key to take full advantage of the association of Variable Compression Ratio (VCR) and Variable Valve Actuation (VVA) in the implementation of Miller-Atkinson cycle, leading to higher thermodynamic efficiency and thus better fuel consumption benefits. VVA systems allow differentiating geometric compression ratio and effective compression ratio. They theoretically permit to maximize expansion ratio (i.e. geometric compression ratio) while keeping an effective compression ratio in accordance with the constraints of the knocking limits, but with a limitation on the reachable maximum Brake Mean Effective Pressure (BMEP) at low compression ratio and the associated downsizing.
2016-04-05
Journal Article
2016-01-1273
Lakshmikanth Meda, Martin Romzek, Yanliang Zhang, Martin Cleary
Abstract Although the technology of combustion engines is reasonably well developed, the degree of efficiency is considerably low. Considerable amount of the energy of around 35 % is lost as exhaust waste heat, and up to 30 % is dissipated in the cooling circuits. Due to this, thermal recuperation has a great potential for raising the efficiency of combustion engines. In order to meet the ever-increasing consumer demand for higher fuel economy, and to conform to more stringent governmental regulations, auto manufacturers have increasingly looked at thermoelectric materials as a potential method to recover some of that waste heat and improve the overall efficiency of their vehicle fleets. Seeking new possibilities to make vehicles greener and more efficient, the industry wants to use the waste heat which passes through the exhaust system almost completely unused in the past.
2016-04-05
Journal Article
2016-01-0258
Jason Aaron Lustbader, Bidzina Kekelia, Jeff Tomerlin, Cory J. Kreutzer, Skip Yeakel, Steven Adelman, Zhiming Luo, John Zehme
Abstract Annual fuel use for sleeper cab truck rest period idling is estimated at 667 million gallons in the United States, or 6.8% of long-haul truck fuel use. Truck idling during a rest period represents zero freight efficiency and is largely done to supply accessory power for climate conditioning of the cab. The National Renewable Energy Laboratory’s CoolCab project aims to reduce heating, ventilating, and air conditioning (HVAC) loads and resulting fuel use from rest period idling by working closely with industry to design efficient long-haul truck thermal management systems while maintaining occupant comfort. Enhancing the thermal performance of cab/sleepers will enable smaller, lighter, and more cost-effective idle reduction solutions. In addition, if the fuel savings provide a one- to three-year payback period, fleet owners will be economically motivated to incorporate them.
2016-04-05
Journal Article
2016-01-0656
Jung Hyun Kim, Taewoo Kim, SungJin Park, JungJae Han, Choongsoo Jung, Young rock Chung, Sangsoo Pae
Abstract In cold start driving cycles, high viscosity of the lubrication oil (engine oil) increases the mechanical friction losses compared with warmed up condition. Thus, an engine oil warm up system can provide the opportunity to reduce the mechanical friction losses during cold start. In this study, an engine oil heater using EGR is used for the fast warm up of the engine oil. This paper presents the effect of the engine oil heater on the fuel economy and emissions over a driving cycle (NEDC). A numerical model is developed to simulate the thermal response of the powertrain using multi-domain 1-D commercial powertrain simulation software (GT-Suite) and it is calibrated using test data from a full size sedan equipped with a 2.0L diesel engine. The model consists of an engine model, coolant circuit model, oil circuit model, engine cooling model, friction model, and ECU model.
2016-04-05
Journal Article
2016-01-0729
Takeshi Okamoto, Noboru Uchida
Abstract To overcome the trade-offs of thermal efficiency with energy loss and exhaust emissions typical of conventional diesel engines, a new diffusion-combustion-based concept with multiple fuel injectors has been developed. This engine employs neither low temperature combustion nor homogeneous charge compression ignition combustion. One injector was mounted vertically at the cylinder center like in a conventional direct injection diesel engine, and two additional injectors were slant-mounted at the piston cavity circumference. The sprays from the side injectors were directed along the swirl direction to prevent both spray interference and spray impingement on the cavity wall, while improving air utilization near the center of the cavity.
2016-04-05
Journal Article
2016-01-1304
Tadayoshi Fukushima, Hitoshi Takagi, Toshio Enomoto, Hiroyuki Sawada, Tomoyuki Kaneda
Abstract Interior noise caused by exterior air flow, or wind noise, is one of the noise-and-vibration phenomena for which a systematic simulation method has been desired for enabling their prediction. One of the main difficulties in simulating wind noise is that, unlike most other noises from the engine or road input, wind noise has not one but two different types of sources, namely, convective and acoustic ones. Therefore, in order to synthesize the interior sound pressure level (SPL), the body sensitivities (interior SPL/outer source level) for both types of sources have to be considered. In particular, sensitivity to the convective input has not been well understood, and hence it has not been determined. Moreover, the high-frequency nature of wind noise (e.g., the main energy range extends up to 4000 Hz) has limited the effective application of CAE for determining body sensitivities, for example, from the side window glass to the occupants’ ears.
2016-04-05
Technical Paper
2016-01-0892
Oliver P. Taylor, Richard Pearson, Richard Stone
Abstract Most major regional automotive markets have stringent legislative targets for vehicle greenhouse gas emissions or fuel economy enforced by fiscal penalties. Large improvements in vehicle efficiency on mandated test cycles have already taken place in some markets through the widespread adoption of technologies such as downsizing or dieselisation. There is now increased focus on approaches which give smaller, but significant incremental efficiency benefits, such as reducing parasitic losses due to engine friction. The reduction in tail pipe CO2 emissions through the reduction of engine friction using lubricants has been reported by many authors. However, opportunities also exist to reduce the lubricant viscosity during warm up by the thermal management of the lubricant mass.
2016-04-05
Technical Paper
2016-01-0823
Jason Miwa, Darius Mehta, Chad Koci
Abstract Increasingly stringent emissions regulations require that modern diesel aftertreatment systems must warm up and begin controlling emissions shortly after startup. While several new aftertreatment technologies have been introduced that focus on lowering the aftertreatment activation temperature, the engine system still needs to provide thermal energy to the exhaust for cold start. A study was conducted to evaluate several engine technologies that focus on improving the thermal energy that the engine system provides to the aftertreatment system while minimizing the impact on fuel economy and emissions. Studies were conducted on a modern common rail 3L diesel engine with a custom dual loop EGR system. The engine was calibrated for low engine-out NOx using various combustion strategies depending on the speed/load operating condition.
2016-04-05
Journal Article
2016-01-1239
Xueyu Zhang, Zoran Filipi
Abstract This paper develops a methodology to optimize the supervisory controller for a heavy-duty series hybrid electric vehicle, with consideration of battery aging and cooling loss. Electrochemistrybased battery aging model is integrated into vehicle model. The side reaction, reductive electrolyte decomposition, is modeled to determine battery aging rate, and the thermal effect on this reaction rate is considered by Arrhenius Law. The resulting capacity and power fading is included in the system-level study. Sensitivity analysis shows that battery aging could cause fuel economy loss by 5.9%, and increasing temperature could improve fuel economy at any given state-of-health, while accelerating battery aging. Stochastic dynamic programming algorithm is applied to a modeled system to handle the tradeoff between two objectives: maximizing fuel economy and minimizing battery aging.
2016-04-05
Journal Article
2016-01-1404
Steven E. Hodges
Abstract Fire protection, active and passive, has been, and is, an important area of concern during the design, development and deployment phases for all modern ground vehicles. All US military vehicles carry handheld fire extinguishers, and many tactical and all combat vehicles have automatic fire protection systems that protect the crew, engine, and in some cases, external components such as fuel tanks and wheels, from potentially catastrophic combat events involving fire. Vehicle designs also mitigate fire hazards by separating the vehicle occupants from the most flammable materials, e.g., fuel and ammunition, as much as practical. Explosion protection of the crew and passengers in military vehicles is a unique application with unique requirements that must balance suppression actions with safety limits.
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