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2015-04-14
Technical Paper
2015-01-1394
Alessandro Naddeo, Marco Apicella, Davide Galluzzi
General comfort may be defined as the “level of well-being” perceived by humans in a working environment. The state-of-the-art about evaluation of comfort/discomfort shows the need for an objective method to evaluate the “effect in the internal body” and “perceived effects” in main systems of comfort perception. Some medical studies show that each human joint has its own natural Rest Posture (RP); in this Rest Posture human muscles are completely relaxed or at minimum strain level: when it happens the geometrical configuration corresponds to the natural position of resting Arms/Legs/Neck etc.. From this starting point, authors developed and build, through a wide experimental campaign, the postural-comfort curves for each DOF of human upper limbs joints; the obtained comfort curves are regular and don’t show any kind of discontinuity. A software named Ca-Man has been developed in order to analyze a general posture and calculate a postural comfort index for the entire upper body.
2015-04-14
Technical Paper
2015-01-1393
Misun Kwon, Sangdo Park, Chanho Jeong, Taehoon Lee, Sanghark LEE, Hoonbok Lee, Jinho Seo
In the era of diversification, car is not only a means of transportation, but also a place of leisure & refreshment. As more and more people drive cars, their demand is growing in a quality & quantity manner. Also industrial development facilitates a development of high class interiors in a car in and out of the world. And consumers prefer their convenience & comfort leading to an increase in demand for a premium car. Above all, car seat is a part where human body touches for the longest time, thereby having impact on consumes' preference for convenience & comfort. In this context, we designed a rear seat convenience system for premium car based on an assessment and comfort analysis according to consumers' tendency and character. Through this system, we aims to enhance the convenience & comfort of seat, and eventually improve passengers' satisfaction.
2015-04-14
Technical Paper
2015-01-1397
Donghee Lee, Younggeun OH
In recent years, trends are changed that a focus on the automotive seat comfort is from the initial and short-term seating feel into the long-term seating feel. However, there was no standardized test method for long-term seating comfort. The aim of this study is to identify a relationship between mechanical properties and stress of seats as one of the objective test methods for long-term evaluation. Totally, 18 samples were prepared with the four identifying factors - three levels of density, hardness and thickness of the PU foam pad, and two levels for stiffness of cushion suspension spring. It was conducted that four kinds of in-lab test and multi-dynamic driving test. Each two sort of static and dynamic comfort in-lab tests were performed to define differences and find relationships among each test samples. Three comfort experts were participated in this study to evaluate each test seats.
2015-04-14
Technical Paper
2015-01-1398
Herbert Reynolds, Ph.D.
Seat design has long searched for a mathematical solution, but the solution has to satisfy human factors in the population, task and government standards. In the automobile, the population defines boundary conditions for seat design and adjustments to fit small to large driver body sizes. The task, however, focuses on vision for vertical rise of the seat for vision and reach for horizontal travel of the seat. The steering wheel and pedals have a relationship with all seated drivers that must meet human factor guidelines for driver performance and comfort. Government standards, however, have imposed a 50 year old tool on vision, reach and seat design through the use of the H-point machine (SAE J826). As a result, seat design has been omitted from interior design with the assumption that the H-point machine will ensure compliance with standards and regulations for the population of drivers.
2015-04-14
Technical Paper
2015-01-1710
Xinran Tao, Kan Zhou, Andrej Ivanco, John R. Wagner, Heath Hofmann, Zoran Filipi
ABSTRACT The components in a hybrid electric vehicle (HEV) powertrain include the battery pack, an internal combustion engine, and the electric machines such as motors and possibly a generator. These components generate a considerable amount of heat during driving cycles. A robust thermal management system with advanced controller, designed for temperature tracking, is required for vehicle safety and energy efficiency. This paper examines the integration of an advanced control algorithm to a HEV powertrain cooling system featuring an electric-mechanical compressor, coolant pump, three radiators, and heat exchanger and radiator fans. Mathematical models are developed to numerically describe the thermal behavior of these powertrain elements. A series of controllers are designed to effectively manage the battery pack, electric motors, and the internal combustion engine temperatures.
2015-04-14
Technical Paper
2015-01-1691
Manabu Matsumoto, Masayoshi Mori, Tomohide Haraguchi, Makoto Ohtani, Tomoya Kubo, Kanji Matsumoto, Hiroshi Matsuda
Exhaust heat recovery units that use a thermoelectric element generate electricity by creating a temperature difference in the thermoelectric element by heating one side and cooling the other side of the thermoelectric circuit (module). In this case, the typical structure does not directly join the thermoelectric module with the heat sink, and instead presses the thermoelectric module against the heat sink using bolts or other means in order to prevent thermoelectric element damage due to the difference in linear expansion between the cooled and heated sides of the thermoelectric module. However, this poses the issues associated with a complex, heavy and expensive structure. Therefore, a new vacuum space structure was devised that houses the thermoelectric module in a vacuum chamber and presses the module against the heat sink using atmospheric pressure.
2015-04-14
Technical Paper
2015-01-1709
Daniel Leighton
Electric drive vehicles (EDVs) have complex thermal management requirements not present in traditional internal combustion engine vehicles. In addition to cabin conditioning, the battery, power electronics, and electric motor drivetrain sub-systems also require thermal management. Many current generation EDVs utilize separate cooling systems for each of these sub-systems, which adds both weight and cost. Another issue for EDVs is the lack of abundant waste heat from the engine for cabin heating. In many cases EDVs use battery energy to heat the cabin via an electrical resistance heater, which results in vehicle range reductions of nearly 50% under cold ambient conditions. These EDV thermal challenges present an opportunity for integrated vehicle thermal management technologies which can reduce cost and weight, and enable efficient heating methods that increase vehicle range.
2015-04-14
Technical Paper
2015-01-0359
Satoki Uematsu, Toshiyuki Uehara, Toshiya Uchida, Gursaran D. Mathur
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 remain operating at idle condition while compressor stops in most cases for these systems. In this case, the air temperature at the vent outlets is likely to increase. 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
Technical Paper
2015-01-1274
Prashant Kaliram Pradip, David S-K. Ting, Graham Reader
Otto cycle engine is one of the most common technology used in automotive industry to produce mechanical power from the chemical energy of the fuel. In the cyclic process, about one third of heat energy produced by combustion is rejected to the exhaust, this limits the efficiency of the engine. Stirling engine is a closed-cycle external combustion engine, which works on a temperature difference and converts the heat energy into mechanical work. It is one of the most efficient engine, which can be used to recover heat from the exhaust of Internal Combustion (IC) engine. This combined Otto and Stirling cycle will substantially increase the overall efficiency of the system. Thermodynamic analysis for the combined system with a primary IC engine to power transmission and a Stirling engine for additional power and efficiency is proposed. The study starts with the modelling of commercially available Otto cycle for engine performance.
2015-04-14
Technical Paper
2015-01-0343
Carlo N. Grimaldi, Claudio Poggiani, Alessandro Cimarello, Matteo De Cesare, Giovanni Osbat lng
The CO2 emission limits for vehicles are becoming more stringent with the aim of reducing greenhouse gas emissions and for improving fuel economy. The New European Driving Cycle (NEDC), adopted to measure all new internal combustion engine emissions in the European Union, is performed on cold vehicle, starting at a temperature of 22°C ± 2°C. So the cold-start efficiency of internal combustion engine is becoming of predominant interest. Since at the cold start the lubricant oil viscosity is higher than at target operating temperature, the consequently higher energy losses due to the friction losses can substantially affect the emission cycle result in terms of fuel consumption and CO2 emission. A suitable thermal management system, such as an exhaust-to-oil heat exchanger, could help to raise the oil temperature more quickly.
2015-04-14
Technical Paper
2015-01-0326
Takuya Yamaguchi, Akira Fukunaga, Yuzo Aoyagi, Noboru Uchida, Takayuki Adachi, Munemasa Hashimoto, Masayuki Kobayashi
Diesel engine is the effective countermeasure for CO2 emission because of high thermal efficiency compare with the other internal combustion engines. On the other hand, diesel engine is strongly required the further improvement of fuel consumption from the point of view of global warming and energy security. Recent years, waste heat recovery technologies such as turbo-compound system, thermoelectric element and combined cycle with Rankine cycle attract much attention as the way of improvement of fuel consumption in addition to the downsizing and down- speeding of engine. In recent years, 2-stage turbocharging system was applied to heavy duty diesel engine to realize high brake mean effective pressure in the low engine speed region which is low mechanical loss.
2015-04-14
Technical Paper
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 cooling airflow temperature over ambient by 18°C, which lowers condenser cooling capacity and increases compressor work. Underhood airflow research 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, and air duct design concepts. 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
Technical Paper
2015-01-1602
Mohamed Abdessalam, Wael I. A. Aly, Gamal Bedair, Ahmed E. Hassaneen
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 optimized exhaust mass flow case at torque 30 Nm after 3hrs from system startup.
2015-04-14
Technical Paper
2015-01-0338
Roberto Monforte, Riccardo Seccardini
Dual Loop System Model: tool for performance analysis and control design Authors: F. Mattiello (CRF), R. Monforte (CRF), M.M. Rostagno (CRF), F. Lovuolo (Altran) The paper focuses on the development of a dual loop system (DLS) model. The secondary coolant loop, working at lower temperature with respect to the engine level, is exploited to cool down the charge air mass flow by means of a coolant-to-air heat exchanger and to provide heat to the HVAC circuit by means of a coolant-to refrigerant condenser. In perspective of the incoming CO2 emission regulation, the on board heat management is becoming more and more relevant to guarantee the engine performance. Other authors have outlined the effect on fuel consumption of the DLS in previous papers by means of prototype tests. The need of a prediction tool for design and performance analysis arises more and more.
2015-04-14
Technical Paper
2015-01-0357
Huize Li, Predrag Hrnjak
This paper presents a method of utilizing infrared images to quantify the distribution of liquid refrigerant mass flow rate in microchannel heat exchangers, which are widely used in automobile air conditioning systems. In order to achieve quantification, a relationship is built between the liquid mass flow rate through each microchannel tube and the corresponding air side capacity calculated from the infrared measurement of the wall temperature. After being implemented in a heat exchanger model, the quantification method is validated against experimental data. This method can be used for several types of heat exchangers and it can be applied to various heat exchanger designs.
2015-04-14
Technical Paper
2015-01-0367
Zhiqiang Hu
The cabin temperature increases quickly and can reach 80℃ when the vehicle parks in the summer sunlight which has the bad influence on the occupants entering comfort. Most luxury vehicles reduce the internal temperature through opening 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 working time because of energy consumption. This research adopts the solar empennage 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. After that, the parameters of the solar empennage are determined according to the control target of the cabin internal temperature.
2015-04-14
Technical Paper
2015-01-1608
Roberto Cipollone, Marco Mauriello, Davide Di Battista
Internal combustion engines are the most important source of propulsive energy in the transportation sector. The expectations of more efficient and performing engines have to match with environmental issues that lead to cleaner vehicles. In fact, the awareness of oil shortage and greenhouse effect has led international governments to impose energy consumption levels which reflects on CO2 emissions: this commitment adds to the emission targets (CO, HC, NOX, PM) which proceed continuously toward lower levels. All of these limits will provide a huge effort on engine and vehicle efficiency with non-negligible costs. CO2 reductions appears the most important issue and it is representing the technological future driver. A smart way match to fulfill the targets concerning CO2 emission is to recover energy usually wasted and re-use it for engine and vehicle needs.
2015-04-14
Technical Paper
2015-01-1658
Xi Luo, Xin Yu, Marcis Jansons
As engine efficiencies continue to rise, heat transfer losses increase in relative importance. Understanding of these phenomena requires accurate in-cylinder wall temperature measurements. A novel dual wavelength infrared diagnostic has been developed to measure in-cylinder surface temperatures with potential temporal resolutions exceeding 1ns. The diagnostic has the capability to measure low amplitude, high frequency temperature variations, such as those occurring during the gas exchange process. A dual wavelength ratio method has also been developed to correct for background scattering reflections. The assumption that scatting reflection effect is constant during an engine cycle has also been provided at all exam engine condition. In-cylinder surface temperatures have been simultaneously measured during motored engine conditions with three independent measurement techniques: thermocouple, laser-induced phosphorescence, and the dual wavelength infrared diagnostic.
2015-04-14
Technical Paper
2015-01-0330
Iman Goldasteh, Shi-Ing Chang, Salamah Maaita, Gursaran Mathur
Proper flow distribution on the windshield and side windows is critical for adequate visibility while driving. Fog or ice which forms on the windshield is the main reason of invisibility and leads to major safety issue. It has been shown that proper clear visibility for the windshield could be obtained with a better flow pattern and uniform flow distribution in the defrost mode of the HVAC system. In this study, a three dimensional numerical model of a car cabin with full HVAC system was developed using Star-CCM+, a commercial CFD package. The Reynolds-Averaged Navier–Stokes equations (RANS) approach with the realizable two-layer k-ε turbulence model was employed for simulating the airflow field on the windshield for the defrost mode. The HVAC unit, ducts and defroster grille were included in the analysis in detail and air distribution on the windshield was studied.
2015-04-14
Technical Paper
2015-01-0335
Sandeep Makam, Christopher Dubbs, Yeliana Roosien, Feng Lin, William Resh
Due to ever-tightening CAFE regulations on passenger vehicles, it is necessary to find novel methods to improve powertrain system efficiency. These increases in efficiency must be cost effective so that the customer perceives that they add value. One approach for improving system efficiency has been the use of thermal energy management. For example, changing the flow of, or reusing “waste” heat from the powertrain to improve efficiency. Due to the interactions involved with thermal management, a system level approach is useful for exploring, selecting, and developing alternative solutions. It provides a structured approach to augment the right kind of synergies between subsystems and mitigate unintended consequences. However, one challenge with using these approaches early in a program is having appropriate metrics for assessing key aspects of the system behaviors.
2015-04-14
Technical Paper
2015-01-1651
Francisco Payri, Jaime Martin, Antonio Garcia, Ricardo Carreño
Determining the weight of different energy terms in a reciprocating engine is a key issue to evaluate the interest of improving a specific thermo-and-mechanical process and to assess the potential of different strategies to reduce the consumption. In this paper, the effect of some parameters variation on the energy repartition of a DI Diesel engine is presented: the experimental work includes variations of coolant and oil temperatures, intake temperature and injection timing at different operating conditions. In each study, the Global Energy Balance (GEB) methodology, based on the experimental measurement of different fluid temperatures and flows, is applied to determine all the relevant energy terms, including heat flow to the coolant and oil, the exhaust gases enthalpy, and the EGR and intercooler heat rejections along with some other minor terms. This information is used to justify in detail the final effect of the parameters on the brake consumption.
2015-04-14
Technical Paper
2015-01-1607
Chuen-Sen Lin, Vamshi Avadhanula, Vamsi Mokkapati, Daisy Huang, Brent Sheets
This paper presents test results of a 50 kilowatt (kW) Organic Rankine Cycle (ORC) system and proposed guidelines for how to effectively apply this system to the rural Alaska power industry. In rural Alaska, approximately 180 villages rely on off-grid diesel generators for power. Most of the generators have capacities of about 1 megawatt (MW) or less. In general, the average operation efficiencies are noticeably less than 40%, with the rest of the fuel energy becoming heat. If the heat is not applied for useful application, it is called waste heat. Most of the wasted heat is contained in engine exhaust and jacket fluid and eventually dissipates into the environment. For rural Alaska, waste heat for heating is most effective; in many cases, waste heat for power may be needed due to a variety of reasons.
2015-04-14
Technical Paper
2015-01-1604
Tianwei(Thomas) Wang, John R. Wagner
**ABSTRACT Smart thermal management systems can positively impact the performance, fuel economy, and reliability of internal combustion engines. Advanced cooling systems typically feature multiple computer controlled actuators - a three way smart valve, a variable speed pump, and a variable speed electric radiator fan(s). To investigate the contributions of these electro-mechanical devices, a scale multifunction test bench was constructed which integrated these actuators, accompanying system sensors, and a controllable engine thermal load with real time data acquisition and control hardware/software. This paper presents a series of experimental studies that focus on the engine’s thermal transient response to various actuator input control combinations. From these test results, several key conclusions can be drawn.
2015-04-14
Technical Paper
2015-01-0337
Blago B. Minovski, Lennart Lofdahl, Peter Gullberg
The current work demonstrates a further step in 1D modeling of cooling systems including discretized cooling package with non-uniform boundary conditions. In a stacked cooling package the heat transfer through each heat exchanger depends on the mass flows and temperature fields through it. These are a result of complex three-dimensional phenomena, which take place in the under-hood and are highly non-uniform. A typical approach in 1D simulations is to assume these to be uniform, which reduces the authenticity of the simulation and calls for additional calibrations, normally done with input from test measurements. The presented work employs 3D CFD simulations of complete vehicle in STAR-CCM+ to perform a comprehensive study of mass-flow and thermal distribution over the inlet of the cooling package of a Volvo FM commercial vehicle in several steady-state operating points.
2015-04-14
Technical Paper
2015-01-0347
Logesh Shankar Somasundaram
The paper aimed at numerically modeling the flow and thermal processes occurring in an agricultural tractor using Computational Fluid Dynamics (CFD) and determines the comfort level of the tractor operator during working condition. The motive of the investigation is to develop and demonstrate capabilities of CFD as an automotive analysis tool. The work describes a methodology that significantly streamlines the process of thermal flow taking place in a tractor by utilizing state-of-the art computer simulation of airflow and heat transfer. The numerical investigation carried out with a three-dimensional geometry of the vehicle assembly from the measurements taken from the vehicle. The geometry created with Pro E, WILDFIRE 3 formed the domain for the automatically generating discretized grids using ANSYS, ICEM CFD. The geometric CAD model used to generate the discretised grid contained the majority of the main components within the under hood environment.
2015-04-14
Technical Paper
2015-01-0363
B. vasanth
In recent years clearing the mist on side windows is one of the main criterions for all OEMs for providing comfort level to the passengers while driving. It will create poor visibility to the passengers when the mist is not cleared on side windows to the desired level. “Windows fog up excessively/don’t clear quickly” is one of the JD Power question to assess the customer satisfaction related to HVAC performance. Defrost/Demist is one of the major issues for all OEMs in recent years. In a Mobile Air Conditioning System, HVAC demister duct and outlet plays an important role for removing the mist formation on vehicle side window. Normally demister duct and outlet design is evaluated by the target airflow and velocity achieved at driver and passenger side window. Multiple flow simulation needs to be carried out for various design configurations of demister outlet until the target velocity is achieved before finalizing the design and its time consuming.
2015-04-14
Technical Paper
2015-01-0878
Guanzhang He, Hui Xie
A two stage turbocharging system is adapted to simulate the power turbine that is installed downstream the charging turbine to further recover waste energy in the exhaust. The potential of energy recovery from the exhaust gas is investigated. The effect of two important controllable factors including injection timing and position of VGT (variable geometry turbocharger) vanes is studied though experiments. The overall fuel consumption benefit, fuel energy distribution, and link efficiency along the energy flow path are involved in the analysis. It is found that total power output of whole system can be enhanced when the exhaust gas is adequate corresponding to the high speed and load engine operating condition. The energy recovered will be counteracted or even less than the power loss of the original engine when low speed and load running condition is considered. The increment of pumping loss plays the dominant role in limiting the further enhancement of total power.
2015-04-14
Technical Paper
2015-01-1662
Manjushri Mahadev Patil, Ashok Pise, Nitin Gokhale
Recently, prediction of cylinder head temperature, using simulation techniques is one of interested tool for engineers. The main aim of this paper work is to predict the temperature field and mechanism of heat transfer prediction along cylinder head of diesel engines. Numerical analysis of conjugate heat transfer (CHT) between cylinder head and coolant was carried out. For the analysis a six cylinder, four cylinder, three cylinder, and two cylinder stationary diesel engines of different BMEP were taken. Simulation model was prepared and solved using commercial CFD software (STARCCM+ 9.O2) in two steps i.e. flow and Conjugate Heat transfer simulation. Flow simulation predicts flow distribution and its flow velocities along with its variation with respect to cylinder location and channel dimensions. Cylinder head is then used for further analysis where flow and heat transfer is solved simultaneously using CHT (conjugate heat transfer) simulation technique.
2015-04-14
Technical Paper
2015-01-1610
Xiaomeng Shen, Quan Zhou
The Organic Rankine Cycle System is an effective approach for recovering the engine exhaust thermal energy. The physical characteristic of the Rankine fluid is the key factor for the capacity and the stability of the expander power output when the engine works in varies condition decided by the road and traffic conditions. In the research, the influences of the evaporator organic medium states and flow rate on the expander power output are fully analyzed for the sufficient utilization of the waste thermal energy. Firstly, the exhaust characteristics of the diesel engine were processed by the data of the bench test. Then, the integral mathematical model of the Organic Rankine Cycle was built. Based on the comparison for the 2-phrase and 3-phrase evaporator, the influence for expander output are analyzed especially emphasis on the factors of engine working condition, the flow rate, temperature and state of Rankine fluid.
2015-04-14
Technical Paper
2015-01-1692
Walter Ferraris, Fausto Di Sciullo, Carloandrea Malvicino, Francesco Vestrelli, Fabrizio Beltramelli, Giancarlo Gotta
Automotive world is rapidly changing driven by the incoming CO2 emission regulation and the need of decreased fuel consumption for every vehicle line. The introduction of high efficiency solutions in order to get fuel consumption reduction has been already done on many vehicle systems without forgetting the cost sustainability of such solutions and with a general trend of weight reduction. For what concerns cooling systems, the increased adoption of dual level cooling loops and water cooled charge air cooling is a clear trend. The present paper proposes a compact and cost effective solution with low temperature loop cooling water cooled charge air cooler and water cooled condenser for A and B segment vehicle, with the possibility to add other exchangers to the secondary loop. All the thermal load is managed by only one radiator.
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