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2016-04-05
Technical Paper
2016-01-0254
Gursaran D. Mathur
Field tests were conducted on a late full sized sedan with the HVAC unit operating in both Recirculation and OSA modes to monitor build-up of the CO2 concentration inside the cabin and its influence on occupant’s fatigue and alertness. These tests were conducted during 2015 summer on interstate highways with test durations ranging from 4 to 7 hours. During the above tests, fatigue or tiredness of the occupants (including CO2 levels) was monitored and recorded at 30 min intervals. Based on this investigation it is determined that the measured cabin concentration levels reaches ASHRAE (Standard 62-1999) specified magnitudes (greater than 700 ppm over ambient levels) with three occupants in the vehicle. Further, the occupants did show fatigue when the HVAC unit was operated in recirculation mode in excess of 5 hours. Further details have been presented in the paper.
2016-04-05
Technical Paper
2016-01-0256
Hideaki Nagano, Kenji Tomita, Yasuhiro Tanoue, Yuji Kobayashi, Itsuhei Kohri, Shinsuke Kato
Abstract In the winter, windshield glass fogging must be prevented through the intake of outdoor air into a vehicle. However, the corresponding energy loss via the ventilation system cannot be ignored. In the present study, the defogging pattern on the windshield is evaluated and the water vapor transportation in the flow field in the vehicle is analyzed in order to investigate the ventilation load by means of a numerical simulation. Some examined cases involve new outlet positions. Additionally, a new, energy-saving air supply method for defogging, with so-called “double-layer ventilator”, is proposed. In this method, one air jet layer is obtained via a conventional defogging opening in the vicinity of the windshield, supplying an outdoor air intake. The other jet consists of recirculated air that covers the outdoor air, preventing it from mixing with the surrounding air.
2016-04-05
Technical Paper
2016-01-0253
Jun Li, Predrag Hrnjak
Abstract This paper presents the experimental analysis of separation in vertical headers based on flow visualization. Two-phase separation phenomena inside the header is observed and quantified. Driving forces are analyzed to study the mechanisms for two-phase flow motion and flow regimes. Main tube of the header is made of clear PVC for visualization study. R-134a is used as the fluid of interest and the mass flux from the inlet pass is 55 kg/m2s - 195 kg/m2s. Potential ways to improve two-phase separation are discussed. A model is built to show how separation brings potential benefits to MAC heat exchangers by arranging the flow path.
2016-04-05
Technical Paper
2016-01-0252
Huize Li, Predrag Hrnjak
Abstract This paper presents the visualization of periodic reverse flow in tubes of an automobile microchannel evaporator. Two microchannel tubes in an off-the-shelf evaporator are modified so that the leading edges are transparent and the rest of the area remains unchanged, providing realistic air heating. Flow visualizations in air heated aluminum tubes and electric heating glass tube are compared and similar flow physics is identified. A mechanistic model of flow reversal is developed. The model is capable of simulating bubble generation, growth coalescence and reverse. The validation against experimental visualization is on the way.
2016-04-05
Journal Article
2016-01-0251
Somnath Sen, Mayur Selokar
Abstract Maintaining thermal comfort is one of the key areas in vehicle HVAC design wherein airflow distribution inside the cabin is one of the important elements in deciding comfort sensation. However, the energy consumption of air conditioning system needs to stay within the efficient boundaries to efficiently cool down the passenger cabin otherwise the vehicle energy consumption may get worsened to a great extent. One approach to optimize this process is by using numerical methods while developing climate systems. The present paper focuses on the numerical study of cabin aiming and cabin cool-down of a passenger car by using computational fluid dynamics (CFD). The main goal is to investigate the cabin aiming with a view to figure out the minimum average velocity over the passengers at all vent positions. Cabin aiming ensures substantial amount of airflow reaches to the passengers as well as every corners of the cabin across the wide climatic range.
2016-04-05
Technical Paper
2016-01-0204
Igor Gritsuk, Yurii Gutarevych, Vasyl Mateichyk, Vladimir Volkov
Abstract The article discusses the features of applying vehicular engine heating system with phase-transitional thermal accumulator. The peculiarity of the presented system is that it uses thermal energy of exhaust gases from internal combustion engine during its operation to accumulate heat. The results of experimental studies of heating the vehicular engine are shown. The article describes the structure of information package for studying the internal combustion engine of a vehicle with heating system and thermal accumulator during the start and after-start heating. The package allows engine performance parameters and engine thermal development to be estimated from distance within intelligent transport systems. Using phase-transitional thermal accumulator in engine coolant heater system (case studied: G4GC (4FS 8.2 / 9.35) of KIA CEE'D 2.0 5MT2) reduces time for heating by 17.8 - 68.4% and fuel consumption by 19.5 - 56.25%.
2016-04-05
Technical Paper
2016-01-0203
Yadong Deng, Chunhua Liu, Panqi Chu
Abstract In order to make full use of engine exhaust heat, the thermoelectric module been used to contribute to thermoelectric power generation in the automotive. At present, the thermoelectric generators (TEGs) have been developing with continuously advances in thermoelectric technology. And almost all of the existing thermoelectric technologies are adding a gas tank to the vehicle exhaust system which increases the exhaust back pressure and occupying excessive space of the vehicle chassis. In this study, a new TEG integrated with a front silencer muffler (FMTEG) is proposed. The muffler is reshaped as the heat exchanger which has a hexagon cross-section. The water tank and clamping mechanism have been redesigned for the new heat exchanger. The FMTEG system’s dimensions are small that can well meet the installation requirements and has a good compatibility with the vehicle exhaust system.
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
2016-01-0201
Armin Traussnig, Wilko Jansen, Heinz Petutschnig, Sepp Steiner, Petra Gruen
Abstract In order to meet current and future emission and CO2 targets, an efficient vehicle thermal management system is one of the key factors in conventional as well as in electrified powertrains. Global vehicle simulation is already a well-established tool to support the vehicle development process. In contrast to conventional vehicles, electrified powertrains offer an additional challenge to the thermal conditioning: the durability of E-components is not only influenced by temperature peaks but also by the duration and amplitude of temperature swings as well as temperature gradients within the components during their lifetime. Keeping all components always at the preferred lowest temperature level to avoid ageing under any conditions (driving, parking, etc.) will result in very high energy consumption which is in contradiction to the efficiency targets.
2016-04-05
Technical Paper
2016-01-0208
Xuzhi Du, Zhigang Yang, Hua Zhou, Qiliang Li, Zheyan Jin
Abstract The effect of jet geometry on flow, heat transfer and defrosting characteristics was numerically investigated for elliptic and rectangular impinging jets on an automobile windshield. Initially, various turbulence models within the commercial computational fluid dynamics (CFD) package FLUENT were employed and validated for a single jet, and the results indicated that the impinging jet heat transfer was more accurately predicted by the SST k -ω turbulence model, which was then utilized for this study. The aspect ratios (AR) of elliptic and rectangular jets were respectively 0.5, 1.0, and 2.0, with jet-to-target spacing h/d=2, 4 and jet-to-jet spacing c/d=4, and all those situations were numerically analyzed with the same air mass flow and jet open area. It was observed that the heat transfer coefficient and defrosting performance of the inclined windshield were significantly affected by the shape of the jet, and the best results were obtained with the elliptic jet arrangements.
2016-04-05
Technical Paper
2016-01-0207
Ivan Arsie, Andrea Cricchio, Cesare Pianese, Vincenzo Ricciardi, Matteo De Cesare
Abstract In the last years, the research effort of the automotive industry has been mainly focused on the reduction of CO2 and pollutants emissions. In this scenario, concepts such as the engines downsizing, stop/start systems as well as more costly full hybrid solutions and, more recently, Waste Heat Recovery technologies have been proposed. These latter include Thermo-Electric Generator (TEG), Organic Rankine Cycle (ORC) and Electric Turbo-Compound (ETC) that have been practically implemented on few heavy-duty applications but have not been proved yet as effective and affordable solutions for passenger cars. The paper deals with modeling of ORC power plant for simulation analyses aimed at evaluating the opportunities and challenges of its application for the waste heat recovery in a compact car, powered by a turbocharged SI engine.
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
Technical Paper
2016-01-0205
Mattia De Rosa, Roy Douglas, Stephen Glover
Abstract The internal combustion (IC) engines exploits only about 30% of the chemical energy ejected through combustion, whereas the remaining part is rejected by means of cooling system and exhausted gas. Nowadays, a major global concern is finding sustainable solutions for better fuel economy which in turn results in a decrease of carbon dioxide (CO2) emissions. The Waste Heat Recovery (WHR) is one of the most promising techniques to increase the overall efficiency of a vehicle system, allowing the recovery of the heat rejected by the exhaust and cooling systems. In this context, Organic Rankine Cycles (ORCs) are widely recognized as a potential technology to exploit the heat rejected by engines to produce electricity. The aim of the present paper is to investigate a WHR system, designed to collect both coolant and exhausted gas heats, coupled with an ORC cycle for vehicle applications.
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
Technical Paper
2016-01-0211
Wang Yiping, Shuai Li, Chunhua Liu, Tao Wang, Panqi Chu
Abstract For vehicle thermoelectric generator, heat would be directly transferred into electricity by thermoelectric modules because there was temperature difference between heat exchanger and water tank. The electrical power generation was deeply influenced by temperature difference, temperature uniformity and topological structure of TEG. In previous works, increasing the difference of temperature would significantly enhance the power generation of TEG and inserted fins were always applied to enhance heat transfer in parallel-plate heat exchanger. But fins would result in a large backpressure which was not conductive to efficiency of the engine.In current study, to enhance heat transfer rates and outside surface temperature, cylindrical grooves on the top and bottom surface in heat exchanger was proposed. The cylindrical grooves could increase the heat transfer area and enhance the turbulence intensity, meanwhile there was no inserts in the fluid to block the flow.
2016-04-05
Technical Paper
2016-01-0210
Taku Matsuda, Yuji Kobayashi, Itsuhei Kohri, Hideaki Nagano, ZongGuang Wang, Saneaki Akieda
Abstract Recently, the evaluation of the thermal environment of an engine compartment has become more difficult because of the increased employment and installation of turbochargers. This paper proposes a new prediction model of the momentum source for the turbine of a turbocharger, which is applicable to three-dimensional thermal fluid analyses of vehicle exhaust systems during the actual vehicle development phase. Taking the computational cost into account, the fluid force given by the turbine blades is imitated by adding an external source term to the Navier-Stokes equations corresponding to the optional domain without the computational grids of the actual blades. The mass flow rate through the turbine, blade angle, and number of blade revolutions are used as input data, and then the source is calculated to satisfy the law of the conservation of angular momentum.
2016-04-05
Technical Paper
2016-01-0209
Youcai Liang
Abstract This paper presents performance of a novel ECCS (electricity-cooling cogeneration system) based on cascade utilization of the waste heat of marine engines. The cogeneration system consists of a steam Rankine cycle and an NH3-H2O absorption refrigeration cycle with an expander. The steam Rankine cycle recycles the energy of both jacket coolant and exhaust gas of engine, while the absorption refrigeration cycle is employed to recover energy of the expanded steam at the turbine outlet in Rankine cycle. The performance of the waste heat recovery system is evaluated in terms of electricity, cooling capacity, equivalent electricity and exergy efficiency. The simulation results show that the novel ECCS exhibited a maximum net electricity output of 4561 kW, a maximum cooling capacity of 3197 kW, and a maximum equivalent electricity of 5233 kW.
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
2016-01-0214
Kaushal Kumar Jha, Ravi Ranjan, Parvej Khan, Lakshmaiah Brahmasani
Abstract For the thermal management of an automobile, the induced airflow becomes necessary to enable the sufficient heat transfer with ambient. In this way, the components work within the designed temperature limit. It is the engine-cooling fan that enables the induced airflow. There are two types of engine-cooling fan, one that is driven by engine itself and the other one is electrically driven. Due to ease in handling, reduced power consumption, improved emission condition, electrically operated fan is becoming increasingly popular compared to engine driven fan. The prime mover for electric engine cooling fan is DC motor. Malfunction of DC motor due to overheating will lead to engine over heat, Poor HVAC performance, overheating of other critical components in engine bay. Based upon the real world driving condition, 1D transient thermal model of engine cooling fan motor is developed. This transient model is able to predict the temperature of rotor and casing with and without holes.
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
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
2016-01-0186.01
Hyunki Sul, Taehoon Han, Mitchell S. Bieniek, John Hoard, Chih-Kuang Kuan, Daniel J. Styles
ERRATUM: In the article Reference 24 should read as follows: 24. Han, T., Booth, A., Song, S., Styles, D., and Hoard, J., “Review and A Conceptual Model of Exhaust Gas Recirculation (EGR) Cooler Fouling Deposition and Removal Mechanism” Proceedings of the Int. Conf. on Heat Exchanger Fouling and Cleaning, 2015”
2016-04-05
Technical Paper
2016-01-0185
Yangjie Ji, Jiaqi Wang, Yingxiao Xu, Ziang Liu, Yongchi Zhou, Jiawei Li
Abstract As an auxiliary braking device of heavy-duty vehicle, eddy current retarder can reduce the brake failure due to the high temperature of the main brake. Nevertheless, the eddy current retarder will generate high temperature locally during the working process of it, leading to the decline of the brake power. The study on the heating characteristics of eddy current retarder is advantageous to the layout and parameter design of the liquid cooling channel of the retarder body and prolong the effective time of the auxiliary brake. In this research, a new kind of integrated eddy current retarder has been established. The thermal-magnetic coupling characteristics are studied and the laws of variation in torque output of auxiliary brake affected by the body temperature of retarder are analyzed. The boundary conditions are provided for the construction of the cooling channel. Firstly, the distribution of magnetic field and the characteristics of eddy current are simulated.
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
2016-01-0191
Gursaran D. Mathur
Water drainage characteristics of an evaporator changes with the age of the vehicle. This is due to the fact that with time, a part of the hydrophilic coating washes off with the moisture that condenses over the evaporator core from the air-stream. Hence, the effectiveness of the evaporator for water drainage deteriorates with the age of the vehicle. At this condition more water is retained in the evaporator as the contact angle increases. Author has conducted experiments with evaporators from multiple vehicles from different OEMs. These evaporators were analyzed to determine the effectiveness of the hydrophilic coating as a function of time or vehicle age. This is the first paper in the open literature that deals with the vehicle mileage or vehicle age with the evaporator plate contact angle and surface coating of an evaporator.
2016-04-05
Journal Article
2016-01-0189
Alaa El-Sharkawy, Ahmed Uddin
Abstract A heat pipe is a self-operating device which is capable of transferring large amounts of heat with a minimum temperature differences between the hot end (evaporator) and the cold end (condenser). However, a limited number of research work or analysis [1,2,3,4,5,6,7,8,9] has been reported in automotive industry on the applications of heat pipes in power train cooling. The advantage of a heat pipe heat exchanger is the possibility to use a more compact and lighter radiator. In addition, the proposed radiator is expected to be more robust as it is less sensitive to variations in ambient temperatures. In this paper, a proposed design for an automotive heat exchanger is investigated. The proposed design is evaluated through thermal simulation of heat pipes using various design parameters. The analysis addresses the ability of the heat exchanger to maintain engine coolant temperature at acceptable limits under different loading conditions.
2016-04-05
Technical Paper
2016-01-0188
Elankathiravan Mathivanan, Liping Liu
In the present work, the effect of various nanofluids on convective heat transfer performance in an automotive radiator was analyzed based on measured nanofluid properties. Al2O3, TiC, SiC, MWNT (multi-walled nanotube) and SiO2 nanoparticles ranging between 1 and 100 nm in size were dispersed in distilled water to form nanofluids. An ultrasonic generator was used to provide uniform particle dispersion in the fluid and keep the mixture stable for a long period of time. The impact of various particle types and their volume concentration on fluid properties such as density, thermal conductivity and viscosity were experimentally analyzed. It is observed that the nanofluid properties increased with the increase in particle volume concentration. TiO2 nanofluids were observed to show the highest increase in density (2.6% higher than the base fluid at a 1% vol. concentration) and also the largest enhancement in thermal conductivity (7.5% augmentation at 1% concentration).
2016-04-05
Technical Paper
2016-01-0187
Zizhen Yu, Gangfeng Tan, Tianming He, Xuexun Guo, MengYing Yang, Shengguang Xiong
Abstract With the improvement of occupants’ awareness on the driving safety, hydraulic retarder applications increase quickly. The traditional hydraulic retarder, on the one hand, exhausts the waste heat of transmission oil by the engine cooling system; on the other hand, the engine power should be consumed to drive the water pump and the engine cooling fan for maintaining the normal operation of the auxiliary braking system. In this study, the Organic Rankine Cycle (ORC) instead of the traditional hydraulic retarder water-cooling system is applied to achieve the effective temperature control of the hydraulic retarder, while the waste heat of transmission oil could be recovered for saving vehicle energy consumption.
2016-04-05
Journal Article
2016-01-0192
Alaa El-Sharkawy, Ahmed Uddin
Abstract Engine mount is one of the temperature sensitive components in the vehicle under-hood. Due to increasing requirements for improved fuel economy, the under-hood thermal management has become very challenging in recent years. In order to study the effects of material thermal degradation on engine mount performance and durability; it is required to estimate the temperature of engine mount rubber during various driving conditions. The effect of temperature on physical properties of natural rubber can then be evaluated and the life of engine mount can be estimated. In this paper, a bench test is conducted where the engine mount is exposed to a step change in the environment around it, and the temperature of the rubber section is recorded at several points till a steady state temperature is reached. A time response curve is generated, from which a time constant is determined.
2016-04-05
Technical Paper
2016-01-0193
Shoichi Imahigashi, Masaharu Sakai, Etsuro Yoshino, Yasushi Mitsuishi
Abstract In recent years, the spread of eco-car has led to the demand for adaptation to low heat source, high efficiency and low noise in vehicle air conditioner. On the other hand, larger interior space of vehicle to assure passenger comfort is demanded, so that the car air-conditioner is required to be smaller. Therefore, we adopted 2-layer HVAC for the air conditioner which can respond to a low heat source. At the same time we have developed the compact high-efficiency 2-layer blower fan for HVAC in order to enable the 2-layer HVAC to be mounted on eco-car with smaller space than conventional HVAC. Generally, because axial flow velocity increases resulting from downsizing of the blower, the ununiform velocity distribution in the axial direction and the turbulent flow between fan blades occurs. It causes the efficiency decrease. To satisfy both downsizing and high-efficiency of the 2-layer blower, we have developed new technologies which can make the flow uniform between fan blades.
Viewing 271 to 300 of 8600