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Viewing 91 to 120 of 10048
2015-04-14
Technical Paper
2015-01-1650
Azmi Osman, Mohd Asmu'i Hussin, Shaiful Fadzil Zainal Abidin
Abstract The drive to reduce CO2 and fuel consumption from passenger cars requires improvements from various subsystems. In particular, the ever growing importance of effective and efficient thermal management will no doubt benefit the quest for more efficient vehicle. While many established automakers have decided to increase the sophistications of the engine cooling circuits through electronics, the increase in complexity and costs are still not desirable especially for A and B passenger car segments. With this in mind, simple mechanical based cooling systems with enhanced functionalities are in high demand. To meet such demand, a simplified engine split cooling circuit previously proposed, simulated and reported seems to be promising. To further verify the indicated advantages, a prototype unit was built and physically tested using a dynamometer with motoring capability.
2015-04-14
Technical Paper
2015-01-0364
Yinhua Zheng
This paper presents the way to optimize vehicle AC system TXV to meet the various AC system requirements. It discusses vehicle AC system TXV sizing and selection process. In today's automotive industry, sizing and selecting the TXV is more complicated than before as various new components are introduced such as external control compressor, internal control compressors and internal heat exchanger etc. These components complicated the system interaction among the components. Thus it requires mapping TXV characteristic to meet the system demand. Sizing TXV capacity, it must start with the vehicle heat load requirement. The type of TXV (i.e. cross charge or parallel charge head) is determined by the system configuration such as compressor, evaporator, and condenser type and with or without internal heat exchanger, etc. To optimize TXV in the system involves in evaluating TXV characteristic and cooling capacity in the various AC operating conditions.
2015-04-14
Technical Paper
2015-01-0360
Maryline Leriche, Wolfgang Roessner, Heinrich Reister, Bernhard Weigand
Abstract An accurate model to predict the formation of fogging and defogging which occurs for low windshield temperatures is helpful for designing the air-conditioning system in a car. Using a multiphase flow approach and additional user-defined functions within the commercial CFD-software STAR-CCM+, a model which is able to calculate the amount of water droplets on the windshield from condensation and which causes the fogging is set up. Different parameters like relative humidity, air temperature, mass flow rate and droplet distributions are considered. Because of the condition of the windshield's surface, the condensation occurs as tiny droplets with different sizes. The distribution of these very small droplets must be obtained to estimate numerically the heat transfer coefficient during the condensation process to predict the defogging time.
2015-04-14
Technical Paper
2015-01-0354
Ji Wan Kim, Tae Hee Lee
Abstract This study has been conducted to analyze microbial diversity and its community by using a method of NGS(Next generation sequencing) technique that is not rely on cultivation for microbial community in an core evaporator causing odor of car air conditioner. The NGS without any cultivation method of cultivation, has been developed recently and widely. This method is able to research a microorganism that has not been cultivated. Differently with others, it can get a result that is closer to fact, also can acquire more base sequence with larger volume in relatively shorter time. According to bacteria population analysis of 23 samples, It can be known limited number of bacteria can inhabit in Evaporator core, due to small exposure between bacteria and evaporate, as well as its environmental characteristics. With the population analysis, only certain group of it is forming biofilm in proportion.
2015-04-14
Technical Paper
2015-01-0358
Praveen Balaj Balakrishnan, Xiaoyong Yu, Ka Chung Chan, Chi Yan Tso, Christopher Chao
Abstract An adsorption air conditioning system is proposed to provide cabin comfort cooling for automotives. This report focuses on the development of a compact adsorption cooling system for automobile applications and its experimental performance. This system uses AQSOA - Z01, an adsorbent material that adsorbs and regenerates water efficiently at low temperature ranges. A water circulation system was built to simulate the process of obtaining heat from exhaust gas heat and providing low-grade thermal energy for the adsorption cooling system. As this system does not need to be powered by the engine as it is in the conventional system, fuel efficiency of the engine can be improved by 10%. This also results in reduction of pollutants due to combustion. The prototype is produced a maximum1310 Watts of cooling power. The system also achieved 650 W/kg SPC (Specific Cooling Power) and a COP (Coefficient of Performance) value of 0.45.
2015-04-14
Technical Paper
2015-01-0352
Kuo-Huey Chen, Jeffrey Bozeman, Mingyu Wang, Debashis Ghosh, Edward Wolfe, Sourav Chowdhury
Abstract The present paper reports on a study of the HVAC energy usage for an EREV (extended range electric vehicle) implementation of a localized cooling/heating system. Components in the localized system use thermoelectric (TE) devices to target the occupant's chest, face, lap and foot areas. A novel contact TE seat was integrated into the system. Human subject comfort rides and a thermal manikin in the tunnel were used to establish equivalent comfort for the baseline and localized system. The tunnel test results indicate that, with the localized system, HVAC energy savings of 37% are achieved for cooling conditions (ambient conditions greater than 10 °C) and 38% for heating conditions (ambient conditions less than 10 °C), respectively based on an annualized ambient and vehicle occupancy weighted method. The driving range extension for an electric vehicle was also estimated based on the HVAC energy saving.
2015-04-14
Technical Paper
2015-01-0351
Jason A. Lustbader, Cory Kreutzer, Steven Adelman, Skip Yeakel, John Zehme
Abstract Annual fuel use for long-haul truck rest period idling is estimated at 667 million gallons in the United States. The U.S. Department of Energy's 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 climate control systems while maintaining occupant comfort. Enhancing the thermal performance of cab/sleepers will enable smaller, lighter, and more cost-effective idle reduction solutions. In order for candidate idle reduction technologies to be implemented at the original equipment manufacturer and fleet level, their effectiveness must be quantified. To address this need, a number of promising candidate technologies were evaluated through experimentation and modeling to determine their effectiveness in reducing rest period HVAC loads.
2015-04-14
Technical Paper
2015-01-1236
John Jaranson, Meraj Ahmed
Abstract The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The MMLV vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three-cylinder engine resulting in a significant environmental benefit and fuel reduction. This paper describes the concept design, prototyping, and validation for interior subsystems of the MMLV. Case studies are presented for two of the interior subsystems: the instrument panel/cross-car beam (IP/CCB) and the front seat structures.
2015-04-14
Technical Paper
2015-01-0350
Zhi Li, Gangfeng Tan, Jing Cai, Zhongjie Yang, YiRui Wang, Haobo Xu
Abstract The vehicle engine exhaust wastes heat. For the conventional scheme, the hot-end of the thermoelectric module is connected with the exhaust pipe, while the cold-end is cooled through the vehicle engine cooling cycle. The variation of vehicle engine operating conditions brings the instability of the hot-end temperature, which affects the power generation performance of thermoelectric materials and increases the damage risk to the thermoelectric materials caused by the high temperature. This research adopts the heat transfer oil circulation as the intermediate fluid to absorb the dynamic heat flux of the vehicle engine exhaust so as to release the heat steadily to the hot-end of the thermoelectric module. The thermal characteristics of the target diesel vehicle engine exhaust gas are evaluated based on the experimental data firstly.
2015-04-14
Technical Paper
2015-01-1230
Ahmed Imtiaz Uddin, Jerry Ku
Abstract It is well known that thermal management is a key factor in design and performance analysis of Lithium-ion (Li-ion) battery, which is widely adopted for hybrid and electric vehicles. In this paper, an air cooled battery thermal management system design has been proposed and analyzed for mild hybrid vehicle application. Computational Fluid Dynamics (CFD) analysis was performed using CD-adapco's STAR-CCM+ solver and Battery Simulation Module (BMS) application to predict the temperature distribution within a module comprised of twelve 40Ah Superior Lithium Polymer Battery (SLPB) cells connected in series. The cells are cooled by air through aluminum cooling plate sandwiched in-between every pair of cells. The cooling plate has extended the cooling surface area exposed to cooling air flow. Cell level electrical and thermal simulation results were validated against experimental measurements.
2015-04-14
Technical Paper
2015-01-1606
Saroj Pradhan, Arvind Thiruvengadam, Pragalath Thiruvengadam, Marc C. Besch, Daniel Carder
Heavy-duty diesel (HDD) engines are the primary propulsion source for most heavy-duty vehicle freight movement and have been equipped with an array of aftertreatment devices to comply with more stringent emissions regulations. In light of concerns about the transportation sector's influence on climate change, legislators are introducing requirements calling for significant reductions in fuel consumption and thereby, greenhouse gas (GHG) emission over the coming decades. Advanced engine concepts and technologies will be needed to boost engine efficiencies. However, increasing the engine's efficiency may result in a reduction in thermal energy of the exhaust gas, thus contributing to lower exhaust temperature, potentially affecting aftertreatment activity, and consequently rate of regulated pollutants. This study investigates the possible utilization of waste heat recovered from a HDD engine as a means to offset fuel penalty incurred during thermal management of SCR system.
2015-04-14
Technical Paper
2015-01-1753
Mario Vila Millan, Stephen Samuel
Abstract Stringent emission norms introduced by the legislators over the decades has forced automotive manufacturers to improve the fuel economy and emission levels of their engines continuously. Therefore, the emission levels of modern engines are significantly lower than pre-1990 engines. However, the improvement in fuel economy is marginal when compared to that of emission levels. For example, approximately 30% of total energy in the fuel is being wasted through the cooling systems in the modern engines. Therefore, thermal management systems are being developed to reduce these losses and offer new opportunities for improving the fuel economy of the vehicles. One of the new emerging technologies for thermal management is the use of nanofluids as coolant. Nanofluids are a mixture of nano-sized particles added to a base fluid to improve its thermal characteristics.
2015-04-14
Technical Paper
2015-01-0329
Mark Hepokoski, Allen Curran, Richard Burke, John Rugh, Larry Chaney, Clay Maranville
Abstract Reliable assessment of occupant thermal comfort can be difficult to obtain within automotive environments, especially under transient and asymmetric heating and cooling scenarios. Evaluation of HVAC system performance in terms of comfort commonly requires human subject testing, which may involve multiple repetitions, as well as multiple test subjects. Instrumentation (typically comprised of an array of temperature sensors) is usually only sparsely applied across the human body, significantly reducing the spatial resolution of available test data. Further, since comfort is highly subjective in nature, a single test protocol can yield a wide variation in results which can only be overcome by increasing the number of test replications and subjects. In light of these difficulties, various types of manikins are finding use in automotive testing scenarios.
2015-04-14
Technical Paper
2015-01-0367
Zhiqiang Hu, Gangfeng Tan, Zhilei Li, Haobo Xu, Wenhui Huang, Yifan Ye
Abstract The cabin air temperature increases quickly and can reach 80°C when the vehicle parks in the summer sunlight which has the bad influence on the occupants entering comfort. Some luxury vehicles, like Audi A8[1], reduce the internal temperature through operating air-condition in advance or using on-board battery to drive the cabin ventilator, which requires relatively complex control system and limits the system's operating time because of energy consumption. This research adopts the solar wing as the ventilation power supply and accomplishes the cabin real-time heat rejection by achieving the steady air circulation for both inside and outside environment. First, the static thermal transfer model of the crew cabin is established. Then, on the basis of the parameters of the prototype ventilation pipe, the ventilation model for the outside circulation is built.
2015-04-14
Technical Paper
2015-01-0355
Matthew A. Jeffers, Larry Chaney, John P. Rugh
Abstract Passenger compartment climate control is one of the largest auxiliary loads on a vehicle. Like conventional vehicles, electric vehicles (EVs) require climate control to maintain occupant comfort and safety, but cabin heating and air conditioning have a negative impact on driving range for all-electric vehicles. Range reduction caused by climate control and other factors is a barrier to widespread adoption of EVs. Reducing the thermal loads on the climate control system will extend driving range, thereby reducing consumer range anxiety and increasing the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have investigated strategies for vehicle climate control load reduction, with special attention toward EVs. Outdoor vehicle thermal testing was conducted on two 2012 Ford Focus Electric vehicles to evaluate thermal management strategies for warm weather, including solar load reduction and cabin pre-ventilation.
2015-04-14
Technical Paper
2015-01-0356
Aniket Patil, Manoj Radle, Biswadip Shome, Sankar Ramachandran
Abstract Passenger comfort and safety are major drivers in a typical automotive design and optimization cycle. Addressing thermal comfort requirements and the thermal management of the passenger cabin within a car, which involves accurate prediction of the temperature of the cabin interior space and the various aggregates that are present in a cabin, has become an area of active research. Traditionally, these have been done using experiments or detailed three-dimensional Computational Fluid Dynamics (CFD) analysis, which are both expensive and time-consuming. To alleviate this, recent approaches have been to use one-dimensional system-level simulation techniques with a goal to shorten the design cycle time and reduce costs. This paper describes the use of Modelica language to develop a one-dimensional mathematical model using Modelica language for automotive cabin thermal assessment when the car is subjected to solar heat loading.
2015-04-14
Technical Paper
2015-01-0353
Kaushal Kumar Jha, Ravi Badathala
Abstract The prime focus of automotive industries in recent times is to improve the energy efficiency of automotive subsystem and system as whole. Harvesting the waste energy and averaging the peak thermal loads using thermal energy storage (TES) materials and devices can help to improve the energy efficiency of automotive system and sub-system. The phase change materials (PCM) well suit the requirement of energy storage/release according to demand requirement. One such example of TES using PCM is extended automotive cabin comfort during vehicle idling and city traffics including start/stop of the engine at traffic stops. PCM as TES poses high density and capacity in thermal energy storage and release. It is due to latent heat absorption and release during phase change. Generally the latent heat of a material compare to it sensible heat is much higher, almost an order of 2.
2015-04-14
Technical Paper
2015-01-0442
Sudhi Uppuluri, Ajay Naiknaware
This paper discusses the sensitivity of key parameters that are used as an input into engine cooling system simulation model that affect the coolant temperature and required airflow calculations. In simulation, these parameters are obtained either from calculations of other programs such as a combustion program or from measured engine test data and are typically assumed to be constant. Tests and measurements from vehicle tests indicate that these parameters always vary affecting the final predicted coolant temperature. The sensitivity on few selected parameters such as the ambient pressure, temperature, humidity, coolant properties among others were studied. Results discussed in this paper quantify the effect of each of these parameters on required airflow and advise which parameters must be tightly controlled to improve the robustness of the simulation model and the accuracy of predictions.
2015-04-14
Journal Article
2015-01-1184
Satyam Panchal, Scott Mathewson, Roydon Fraser, Richard Culham, Michael Fowler
Abstract The performance, life cycle cost, and safety of electric and hybrid electric vehicles (EVs and HEVs) depend strongly on their energy storage system. Advanced batteries such as lithium-ion (Li-ion) polymer batteries are quite viable options for storing energy in EVs and HEVs. In addition, thermal management is essential for achieving the desired performance and life cycle from a particular battery. Therefore, to design a thermal management system, a designer must study the thermal characteristics of batteries. The thermal characteristics that are needed include the surface temperature distribution, heat flux, and the heat generation from batteries under various charge/discharge profiles. Therefore, in the first part of the research, surface temperature distribution from a lithium-ion pouch cell (20Ah capacity) is studied under different discharge rates of 1C, 2C, 3C, and 4C.
2015-04-14
Technical Paper
2015-01-1254
Daishi Takahashi, Koichi Nakata, Yasushi Yoshihara, Yukinori Ohta, Hiroyuki Nishiura
Abstract In recent years, enhancing engine thermal efficiency is strongly required. Since the maximum engine thermal efficiency is especially important for HVs, the technologies for improving engine thermal efficiency have been developed. The current gasoline engines for hybrid vehicles have Atkinson cycle with high expansion ratio and cooled exhaust gas recirculation (EGR) system. These technologies contribute to raise the brake engine thermal efficiency to more than 38%.In the near future the consumers demand will push the limit to 40% thermal efficiency. To enhance engine thermal efficiency, it is essential to improve the engine anti-knock quality and to decrease the engine cooling heat loss. To comply with improving the anti-knock quality and decreasing the cooling heat loss, it is known that the cooled EGR is an effective way.
2015-04-14
Technical Paper
2015-01-1658
Xi Luo, Xin Yu, Marcis Jansons
Abstract As engine efficiency targets continue to rise, additional improvements must consider reduction of heat transfer losses. The development of advanced heat transfer models and realistic boundary conditions for simulation based engine design both require accurate in-cylinder wall temperature measurements. A novel dual wavelength infrared diagnostic has been developed to measure in-cylinder surface temperatures with high temporal resolution. The diagnostic has the capability to measure low amplitude, high frequency temperature variations, such as those occurring during the gas exchange process. The dual wavelength ratio method has the benefit of correcting for background scattering reflections and the emission from the optical window itself. The assumption that background effects are relatively constant during an engine cycle is shown to be valid over a range of intake conditions during motoring.
2015-04-14
Journal Article
2015-01-0359
Satoki Uematsu, Toshiyuki Uehara, Toshiya Uchida, Gursaran D. Mathur
Abstract In last 10 years or so, a number of OEMs are designing vehicles with start-stop function to save energy and to reduce pollution. For these systems, the situations in which air-conditioning systems are used have been changing with a significant increase in adoption of idle-time reduction systems (no idling-system). Blower fan remains operating at idle condition while compressor stops in most cases for these systems. In this case, the air temperature at the vent outlets increases. The increase in the air temperature under range of thermal boundary conditions around the evaporator causes a concern of odor to occur. This paper describes and explains experimental studies on changes in heat and humidity at the air outlets according to the switching operation of compressor and root cause analyses of odor coming from air-conditioning system for vehicles with start-stop function.
2015-04-14
Journal Article
2015-01-0371
Rupesh Sonu Kakade, Prashant Mer
Abstract The human thermal comfort, which has been a subject of extensive research, is a principal objective of the automotive climate control system. Applying the results of research studies to the practical problems require quantitative information of the thermal environment in the passenger compartment of a vehicle. The exposure to solar radiation is known to alter the thermal environment in the passenger compartment. A photovoltaic-cell based sensor is commonly used in the automotive climate control system to measure the solar radiation exposure of the passenger compartment of a vehicle. The erroneous information from a sensor however can cause thermal discomfort to the occupants. The erroneous measurement can be due to physical or environmental parameters. Shading of a solar sensor due to the opaque vehicle body elements is one such environmental parameter that is known to give incorrect measurement.
2015-04-14
Journal Article
2015-01-1391
Scott Allen Ziolek, Joshua Pryor, Tony Schwenn, Adam Steinman
Abstract Optimizing climate seat systems requires increased complexity in seat design which in turn is driving a need for more detailed thermal simulation methods. This paper presents the model development considerations and results of a thermal simulation study aimed at improving the thermal seat comfort experience of Hyundai-Kia's heated seating systems.
2015-04-14
Journal Article
2015-01-1379
Hideki Matsumura, Shinichiro Itoh, Kenichi Ando
Abstract Lithium-ion cells are being used in an increasing number of electric and hybrid vehicles. Both of these vehicle types contain many cells. Despite various safety measures, however, there are still reports of accidents involving abnormal heat, smoke, and fire caused by thermal runaway in the cells. If thermal runaway in one cell triggers that of another and thus causes thermal runaway propagation, this can lead to rupture of the battery pack, car fire, or other serious accidents. This study is aimed to ensure the safety of vehicles with lithium-ion cells by clarifying such accident risks, and so we investigated the process of thermal runaway propagation. In the experiment, we created a battery module made of seven laminate-type cells tightly stacked one on another. Then, we induced thermal runaway in one of the cells, measured the surface temperatures of the cells, and collected video data as the process developed. As a result, all of the seven cells underwent thermal runaway.
2015-04-14
Journal Article
2015-01-1392
Se Jin Park, Seung Nam Min, Murali Subramaniyam, Heeran Lee, Yu Kyung Shin, Chang Hee Jang, Soon Hyun Hwang
Abstract Driving posture measurement is essential for the evaluation of a driver workspace and for improved seat comfort design. This study captures the comfortable driving postures for Koreans using a handheld portable Artec L™ 3D scanner. Subjects consisted of 20 healthy individuals (10 males and 10 females) ranging in age from 20 to 40 years and grouped as three weight groups (<59 kg, 60-79 kg and >80 kg). Eighteen land markers were attached (car seat: 9 markers; subject: 9 markers). From the 3D scanned data, the angles (neck, back, headrest, seat back, wrist, elbow, knee, and ankle) and distances (head to headrest, seat height, and seat back and forth) between the land markers were extracted in the Rapidform XOR software. The body pressure distribution was measured using two pressure mats from 17 body part regions. The measured pressure data were analyzed for average pressure, contact area, and body part pressure ratio.
2015-04-14
Journal Article
2015-01-1526
Yasuyuki Onishi, Thomas Ramsay, Timothy Juan, James McKillen
Abstract A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept.
2015-04-14
Journal Article
2015-01-1709
Daniel Leighton
Abstract Electric drive vehicles (EDVs) have complex thermal management requirements not present in conventional vehicles. In addition to cabin conditioning, the energy storage system (ESS) and power electronics and electric motor (PEEM) subsystems also require thermal management. Many current-generation EDVs utilize separate cooling systems, adding both weight and volume, and lack abundant waste heat from an engine for cabin heating. Some use battery energy to heat the cabin via electrical resistance heating, which can result in vehicle range reductions of 50% under cold ambient conditions. These thermal challenges present an opportunity for integrated vehicle thermal management technologies that reduce weight and volume and increase cabin heating efficiency. Bench testing was conducted to evaluate a combined fluid loop technology that unifies the cabin air-conditioning and heating, ESS thermal management, and PEEM cooling into a single liquid coolant-based system.
2015-04-14
Journal Article
2015-01-1689
Xu Song, Ryan Fortier, Scott Sarnia
The underhood hot air recirculation greatly impacts A/C system performance at idle and low vehicle speed conditions. The hot air recirculation can raise condenser inlet air temperature in some cases as much as 18°C above ambient, which lowers condenser cooling capacity and increases compressor work. Underhood airflow research in the following study suggests that a properly designed air duct is able to minimize hot air recirculation and improve the Compressors Coefficient of Performance (COP) at idle by 27%. This paper discusses underhood hot air recirculation testing methods, airflow distribution, air duct design concepts, as well as the cross wind and wind tunnel effects. This dedicated air duct design indicates it should improve A/C emissions, which could contribute to meeting the Environmental Protection Agency's (EPA) Green House Gas Emissions Regulations in North America.
2015-04-14
Journal Article
2015-01-0782
Philipp Huegel, Heiko Kubach, Thomas Koch, Amin Velji
Abstract In this work, heat loss was investigated in homogeneous and stratified DI-SI operation mode in a single cylinder research engine. Several thermocouples were adapted to the combustion chamber surfaces. The crank angle resolved temperature oscillations at the cylinder head and piston surface could thereby be measured in homogeneous and stratified operation mode. A grasshopper linkage was designed and adapted to the engine, to transfer the piston signals to the data acquisition device. The design of the experimental apparatus is described briefly. For both operation modes the average steady-state temperatures of the combustion chamber surfaces were compared. The temperature distribution along the individual sensor positions at the cylinder head and piston surface are shown. Furthermore, the curves of the crank angle resolved temperature oscillations in stratified and homogeneous operation mode were compared.
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