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Viewing 31 to 60 of 9983
2015-04-14
Technical Paper
2015-01-0349
Suvankar Manna, Yogendra Singh Kushwah
With stringent requirements of fuel efficiency and emissions, the airflow and thermal management within the under-hood environment is gaining significance day by day. While adequate airflow is required for cooling requirements under various vehicle operating conditions, it is also necessary to optimize it for reduced cooling drag and fan power. Hence, the need of the day is to maximize cooling requirements of Condenser, Radiator ,CAC and other heat exchangers with minimal power consumption. To achieve this objective and due to the complicated nature of 3D flow phenomenon within the under-hood environment, it is useful to perform 3D CFD studies during preliminary stages to shorten design time and improve the quality and reliability of product design. In this paper we present the results from a CFD under-hood analysis that was carried out for design, development and optimization of a CRFM (Condenser, Radiator and Fan Module).
2015-04-14
Technical Paper
2015-01-0352
Kuo-Huey Chen, Jeffrey Bozeman, Mingyu Wang, Debashis Ghosh, Edward Wolfe, Sourav Chowdhury
The HVAC system imposes the largest accessory load on an electric vehicle to meet comfort heating and cooling needs. Thus the HVAC energy consumption can have a major impact on the driving range of a pure electric vehicle (EV) or an extended range electric vehicle (EREV such as Chevy Volt). Traditionally, the vehicular HVAC system is designed to cool and heat the entire cabin to provide passenger comfort. Localized cooling and heating, on the other hand, focus on keeping the passenger comfortable by creating a micro climate around the passenger. Such a system can easily adapt to the number of passengers in the car and enables zonal control. The net impact of the localized cooling and heating system is that equivalent comfort can be achieved at a reduced HVAC energy consumption rate. The present paper reports on a study for an EREV implementation of a localized cooling/heating system using thermoelectric (TE) nozzle devices to target the occupant’s chest, face, lap and foot areas.
2015-04-14
Technical Paper
2015-01-0370
Modar Horani, Osamah Rawashdeh
Traditional Heat Ventilation and Air Conditioning (HVAC) control systems are reactive by design and largely dependent on the on-board sensory data available on a Controller Area Network (CAN) bus. The increasingly common Internet connectivity offered in today’s vehicles, through infotainment and telematic systems, makes data available that may be used to improve current HVAC systems. This includes real-time outside relative humidity, ambient temperature, precipitation (i.e., rain, snow, etc.), and weather forecasts. This data, combined with position and route information of the vehicle, may be used to provide a more comfortable experience to vehicle occupants in addition to improving driver visibility through more intelligent humidity, and defrost control. While the possibility of improving HVAC control utilizing internet connectivity seems obvious, it is still currently unclear as to what extent.
2015-04-14
Technical Paper
2015-01-1652
Yukikatsu Ozaki, Keisuke Sekiya
This research developed new measurement technology for thermal analysis of the heat radiated from a hybrid vehicle transaxle case surface to the air and improved the heat radiation performance. In thermal analysis, the temperature distribution of the case surface and the amount of heat radiation from the surface to the air are measured. In order to quantify heat radiating from the surface into the air, the heat flux measurement is required. Until now, various heat flux sensors were proposed. For example, the thermopiles were used to measure the heat flux in the conventional sensors. These electrically measure the temperature difference between the surface and the back side of a thin plate with low thermal conductivity. However, conventional heat flux sensors require the installation of sensor wiring and this affects the flow field and the temperature field of measuring object. Therefore, these are unsuitable for multipoint measurement of heat flux.
2015-04-14
Technical Paper
2015-01-1713
Manfred Klaus Kirschning, Frank Reußwig
In recent years, the automotive industry has taken many efforts to satisfy the market requirements of reducing fuel consumption and the emission of pollutants. In consequence engines had to be compacted and many additional modules had to be integrated into the confines of tightly packed engine compartments. The narrow confines also limited the options for piping options, for instance with preformed rubber tubes or oil flow and return pipes. Many of these components are designed for a maximum permanent temperature of 140°C to 180°C only. Other components, for example oil pipes, cannot be applied in settings with temperatures higher than 140°C because of the cracking of the hydrocarbon molecules.
2015-04-14
Technical Paper
2015-01-1702
Alex Wang, Jung Hsien Yen
This paper presents a novel technology to achieve world lowest power (4W) FOG lamp by single LED design which is much enhanced than the existing 2-3 LEDs solutions. This design saves 92.7% energy than conventional Halogen lamp(55W) and saves 38.4% than existing LED FOG lamp(6.5W). The optical design adopts the optimized multifaceted reflector, with precise and unique optimization design scheme, we are able to generate a very sharp cut-off line with a 3.2W LED to enable stronger light penetration in low vision weather condition. The efficiency of multifaceted reflector optics in this study is 50.9% which is 27% higher than the existing reflector design. Design details, anti-block skills and the manufacturing tolerance control are analyzed in this paper. The total light output of the LED fog lamp is 210lm, the L6-line minimal is 4200cd above the ECE R19 requirement of 2700cd.
2015-04-14
Technical Paper
2015-01-0332
Ravi ranjan, Kaushal Kumar Jha, Parvej khan, Lakshmaiah Brahmasani
For the thermal management of an automobile, the induced air flow become necessity to enable the sufficient heat transfer with ambient. In this way, the components works within the designed temperature limit. The induced air flow is enabled by the engine cooling fan. There are two types of engine cooling fan, one which is driven by engine itself and other one as electrically driven. Due to ease in handling, reduced power consumption, improved emission condition, electrically operated fan 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 was developed. This transient model is able to predict the temperature of rotor and casing with and without holes.
2015-04-14
Technical Paper
2015-01-0333
Ravi Badathala, Kaushal Kumar Jha
Due to Increase in demand of comfort in vehicle cabin, thermal management of cabin became very important parameter in Automotive HVAC system. Estimated component performance with test bench conditions, are always not same when components are working along with other HVAC components in actual working conditions. Developing accurate simulation models to predict the HVAC performance at different test cycles using component level performance curves, gives a reliable insight to the HVAC behavior during a performance test. This will also reduce the physical effort & test cost. To ensure the components are well versed with the vehicle working environment a, virtual model of transient condition with control logic has been developed using commercial 1D software. During the transient simulation of HVAC System performance for a cool down test with compressor and evaporator Controls, balancing of individual components with other system components is ensured.
2015-04-14
Technical Paper
2015-01-0356
Aniket Patil, Manoj Radle, Biswadip Shome, Sankar Ramachandran
Passenger comfort and safety are major drivers in a typical automotive design and optimization cycle. To address thermal comfort requirements, thermal management of the passenger cabin in a car which involves accurately predicting 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 has 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 Dymola for automotive cabin thermal assessment when the car is subjected to solar heat loading.
2015-04-14
Technical Paper
2015-01-0720
Dinesh Pahuja, Vijay kumar, Arpit Kapila
Door trim insert plays a very important role for making vehicle aesthetic appealing and pleasing through addition of skin over the Door trim insert substrate. In automotive industry, for side door trim insert decoration and skin pasting, large number of bonding techniques are available. This paper will focus mainly on analyzing the effect of skin type and its construction on automotive side door trim insert having thermo compression molding as a pasting technique. Properties of skin like elongation and bending resistance etc., affect the appearance of door trim insert after pasting of skin. And the selection of skin type and specifying its properties for door trim insert is a challenge for an automotive interior designer. In automotive applications, different materials are used for Door trim insert skin e.g. woven fabric, knit fabric, PVC and leather.
2015-04-14
Technical Paper
2015-01-1611
Wei Liu
When the hydraulic retarder is working in the heavy-duty vehicle, almost all the braking power is transformed into the thermal energy of the transmission oil. The spare heat removal capacity of engine’s cooling system could be taken full advantage for cooling the retarder. However, the relative long distance of the engine and the retarder increases the risky leakage of the cooling circuit. Furthermore, the development trend of heavy load and high speed vehicle directs the significant increase in the thermal load of the hydraulic retarder, which even higher than the engine power. Conventional engine cooling system could not meet the demand of the hydraulic retarder heat rejection within the same installation space. In this research, independent two-phase evaporator was adopted to strengthen the coolant heat absorption capacity from the transmission fluid at the oil outlet of the retarder by means of the vacuum flow boiling heat transfer.
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 is inevitably linked to a reduction in thermal energy of the exhaust gas. Thus contributing to lower exhaust temperature of after-treatment activity, necessary for maintaining the aftertreatment system within a favorable temperature range.
2015-04-14
Technical Paper
2015-01-0336
Amey Karnik, Daniel Pachner, Adrian M. Fuxman, David Germann, Mrdjan Jankovic, Christopher House
Numerous studies describe the fuel consumption benefits of changing the powertrain temperature based on vehicle operating conditions. Actuators such as electric water pumps and active thermostats now provide more flexibility to change powertrain operating temperature than traditional mechanical-only systems did. Various control strategies have been proposed for powertrain temperature set-point regulation. A characteristic of powertrain thermal system is that the system operating conditions change continuously to meet the driver demand. Control strategies for set-point regulation which rely purely on feedback for disturbance rejection, without knowledge of future disturbances, might not provide the full fuel consumption benefits due to the slow thermal inertia of the system. A solution to this problem is to design a control strategy that utilizes the estimate of variability of future disturbances.
2015-04-14
Technical Paper
2015-01-0372
Rupesh Sonu Kakade
Automotive air conditioning systems are equipped with one or two air inlet doors, controlled by one or two actuators (stepper or DC motors), to obtain desired mixing of air from inside and outside of the passenger compartment. Apart from influencing the primary objective of cabin cooling, mixing ratio between two masses of air has effect on cabin air quality - in terms of odor and pollen, oxygen and carbon dioxide levels of cabin air, window defogging and compressor load on engine. The analytical method is proposed to obtain compressor work for given cooling requirement and mixing ratio for known coefficient of performance of compressor, mass flow of evaporator air and enthalpies of air from outside and inside of the passenger compartment. The compressor work is a linear function of mixing ratio for the unsaturated evaporator outlet air and is a quadratic function for the saturated evaporator outlet air.
2015-04-14
Technical Paper
2015-01-0348
Chuqi Su, Meng Xu, Naiqiang Tong, Yulian CHEN
The potential for automotive exhaust-based thermoelectric generator (TEG) has been increasing with continuously advances in thermoelectric technology. In this paper, the thermal deformation of the TEG system is studied on the basis of the temperature distribution of the heat exchanger. The simulation analysis shows that the thermoelectric modules (TMs) on different positions of the heat exchanger have different thermal performance, which can significantly influence the power generation efficiency of the system. Meanwhile, it is found that the thermal performance is affected by the clamping mechanism, which has a greater effect on the cold side than the hot side. Following the simulations, bench tests are carried out to confirm the reasonability of the simulation results.
2015-04-14
Technical Paper
2015-01-1694
Jun Li, Predrag Hrnjak
This paper presents results of the visualization of the separation in the vertical header of the automotive condenser. A prototype of a heat exchanger was made that has inlet in the middle of the header, with 21 microchannel tubes as the first pass. In the second header liquid separates and leaves through 4 microchannel tubes beneath while mostly vapor leaves through 11 microchannel tubes on the top as another exit. That way the 2nd pass has liquid below first pass and vapor above it. R134a and R1234yf are used in the tests. Mass flow was in the range 30 - 80 g/s (mass flux 170 kg/m2·s to 450 kg/m2·s) and quality at the inlet to second header over a range of 0.1 to 0.3, to see their impact on the separation of two-phase flow inside the transparent header. Visualization data were taken to better understand and define the physical parameters that dominate the separation phenomena.
2015-04-14
Technical Paper
2015-01-1660
Jose Ramon Serrano, Francisco Arnau, Jaime Martin, Manuel Hernandez, Benoit Lombard
This paper presents experiments on the effect of thermal insulation of engine internal walls on the performance and emissions of a heavy-duty diesel engine. Some parts of the engine, like pistons, cylinder head and exhaust manifold were insulated in order to reduce heat loses through the walls. Each component has been analysed first independently and then in combination with others. The results obtained in a test bench have been compared to the original engine configuration. This analysis focuses on parameters such as NOx emissions, smoke and break specific fuel consumption. In order to take advantage of the engine insulation, a swept of the injection setting was also performed, which provided the best combination of start of injection (SOI) and pump injector needle opening pressure (NOP).
2015-04-14
Technical Paper
2015-01-0346
Lei dongxu
Due to the latent heat of vaporization, the efficiency of boiling heat transfer is several times and even dozens of times higher than that of the convection heat transfer. With the improvement of power density of the engine, there are more requirements for engine cooling system design. It has been confirmed that the subcooled boiling did exist in the engine cooling. If boiling heat transfer can be reasonablely used, we can achieve the objective of enhancing heat transfer without changing the existing structure. In this paper, in order to quantitatively research the subcooled boiling in the engine, we simulated the subcooled boiling in the analog channel with the Euler multiphase model, found the importance of the turbulent dispersion. In additon, we explored the applicability of existing models to subcooled boiling, and compared the results with the experiment.
2015-04-14
Technical Paper
2015-01-0365
Gursaran D. Mathur
In a recent investigation (Mathur, 2014), the author had investigated the amount of energy stored in vehicle's Cockpit Module (CPM) at high ambient and at high solar heat loads for a MY2012 production vehicle. Detailed analysis was presented to show the influence of energy stored in various components (e.g., instrument panel, HVAC system, heat exchanger, wire harness, etc.) contained within the CPM unit. Experiments were conducted to show the amount of energy stored at high ambient and solar conditions. This is a follow up study to the above investigation. In this investigation, same vehicle is used to determine the amount of energy stored at cold temperatures, say at -20°C temperature that is used for a majority of heating, windshield and window de-fogging and de-icing tests.
2015-04-14
Technical Paper
2015-01-0351
Jason Aaron Lustbader, Cory Kreutzer
Annual fuel use for sleeper cab truck rest period idling is estimated at 667 million gallons in the United States. Idling of the truck during a rest period represents a zero freight efficiency condition and is partially done to supply accessory power for climate conditioning of the cab. The U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory’s (NREL) CoolCab project aims to reduce 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 from new technologies provide a one- to three-year payback period, fleet owners will be economically motivated to incorporate them.
2015-04-14
Technical Paper
2015-01-0369
Rupesh Sonu Kakade
Apart from thermal comfort of occupants, their safety by ensuring adequate visibility is the primary objective of automotive climate control systems. Integrated dew point and glass temperature is widely used senor among several technologies to detect risk of fog formation on the windshield. The erroneous information from sensor such as the measurement lag can cause imperfect visibility due to delayed response of climate control system. A differential equation model of cabin air humidity is proposed to calculate in real-time the ambient humidity of passenger compartment. The specific humidity from the model is used to determine relative humidity for a known window surface temperature. The uniform spatial distribution of cabin air humidity is used to advantage. However non-uniform distribution of window surface temperature and the uncertainty of parameters of differential equation model are evaluated to determine risk of fogging to an acceptable accuracy.
2015-04-14
Technical Paper
2015-01-1654
Billy G. Holland, Thomas L. McKinley, Bill R. Storkman
Cooled EGR continues to be a key technology to meet emission regulations, with EGR coolers performing a critical role in the EGR system. Designing EGR coolers that reliably manage thermal loads is a challenge with thermal fatigue being a top concern. The ability to estimate EGR cooler thermal fatigue life early in the product design and validation cycle allows for robust designs that meet engine component reliability requirements and customer expectations. This paper describes a process to create an EGR cooler thermal fatigue life model. Components which make up the EGR cooler have differing thermal responses, consequently conjugate transient CFD must be used to accurately model metal temperatures during heating and cooling cycles. Those metal temperatures are then imported into FEA software for structural analysis. Results from both the CFD and FEA are then used in a simplified numerical model to estimate the virtual strain of the EGR cooler.
2015-04-14
Technical Paper
2015-01-1609
Roberto Monforte, Riccardo Seccardini
New MAC Technologies: Fuel Efficiency Effect in Real Driving of the air intake flap management Authors: R. Monforte (CRF), M.M. Rostagno (CRF), R. Seccardini (CRF), F. Lovuolo (Altran) Following the development of new technologies in Vehicle Thermal Management aiming to both reducing the thermal load to be managed by the Mobile Air Conditioning and enhancing its efficiency, a prediction tool based on the AMESim platform was developed at CRF in the Interiors & Engine Systems Area dedicated to predict the effect of the implementation of sensors monitoring both the relative humidity and the CO2 concentration (taking into account passenger moisture and carbon dioxide production). This model is implemented with the usual comfort inputs (CO2 and r.H. acceptable ranges), it considers the system variables influencing the comfort and predicts the grow-up of both relative humidity and CO2 concentration in the cabin compartment in any driving cycle depending on the number of occupants.
2015-04-14
Technical Paper
2015-01-1700
John D. Bullough
Warning lights and beacons on service vehicles such as maintenance trucks, tow trucks, utility service vehicles and delivery vehicles are an important line of defense for the workers who operate them. These lights can also contribute to visual chaos making it difficult to navigate through a work zone location. Research on the flashing configuration and spatial and temporal coordination of warning lights that adapt to ambient conditions and situations will be described, leading to recommendations for preliminary performance specifications.
2015-04-14
Technical Paper
2015-01-0331
Sina Shojaei, Simon Robinson, Chris Chatham, Andrew McGordon, James Marco
Among the auxiliary systems in electric and hybrid electric vehicles the electric air conditioning (eAC) system causes the largest load on the high voltage battery and can significantly impact the energy efficiency and performance of the vehicle. Several design and energy management optimisation methods can be employed to reduce this impact. As part of the Energy Efficiency Workstream of UK’s High Value Manufacturing Catapult Project, new methods are being developed that allow effective management of air conditioning loads through their integration into vehicle level energy management strategies. To this end, a fully integrated vehicle model is required. As a first step, a model of a commercially available hybrid vehicle is developed which includes an eAC module based on finite control volume principles.
2015-04-14
Technical Paper
2015-01-0345
Zhi Li, Zhanwei Tian
When the vehicle parks in hot environment, the cabin will become high temperature thermal environment, which has the bad impact on the entering comfort of occupants. Ventilation is an effective measure for thermal environment applications, and the current method in the car is more to automatically open ventilation system in a short time before the car starts, reaching the pre-cooling purpose and making the air temperature inside the car decreased rapidly. For this way, the working hours of ventilation is limited with great energy consumption. In this study, the original car ventilation system and newly designed exhaust fan are driven by the solar panels at the same time, exhausting the heat inside the cabin real-time and achieving the pre-cooling purposes. Firstly, the impacts of the vehicle ambient temperature, the solar radiation intensity and other factors on the interior cabin temperature were analyzed.
2015-04-14
Technical Paper
2015-01-0329
Mark Hepokoski, Allen Curran, Richard Burke, John Rugh, Larry Chaney, Clay Maranville
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 comprising 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
2015-01-1663
Prafulla P Ghare, Hemant Khalane, Udaysingh Wakhure, Tushar Khobragade, Sandip Chaudhari, Atul Jahirabadkar
As one of the most complicated parts of an internal combustion Engine, the cylinder head is directly exposed to high combustion pressures and temperatures. Cooling must be provided for the heated surfaces to avoid overheating. However over-cooling will cause problems such as lower overall efficiency and high emission. Therefore, an optimal design of the cooling system is required to maintain trouble-free operation of engine. For single cylinder naturally aspirated engines, designer has to package injector, valve guide bores, head bolt bosses and intake and exhaust valve ports in limited space. On account of these space restrictions, designing of cooling jacket is very critical. Engineers invest a large amount of time and serious effort to optimize the flow through engine cooling jacket. The complicated structure of a cylinder head leads to the difficulty in acquiring detailed information of conducting flow and heat transfer.
2015-04-14
Technical Paper
2015-01-0334
Vaishali Mahavir patil, Vinay Vaidya PhD
Today’s Automotive Industry is emphasizing more on passenger comfort and HVAC (Heating, Ventilation, and Air Conditioning) is one of the systems which is playing vital role in providing it. Automotive engineers are working towards developing efficient and optimized HVAC system to achieve maximum passenger comfort and good fuel efficiency. State-of-art technique uses CFD (Computational Fluid Dynamics) tools to model and study air-flow and temperature distribution in the CAR cabin, which is based on the fluid dynamics. These tools are very costly and require more computational power and time. The proposed work presents an empirical mathematical model of the CAR cabin temperature distribution in two-dimensional space. The mathematical equations are very simple and based on basic theory. The time required in simulating the temperature and air-flow distribution using these equations is very less as compared to CFD tools.
2015-04-14
Technical Paper
2015-01-0366
Stephanie Stockar, Cristian Rostiti, Marcello Canova
In a scenario where the automotive industry is striving to significantly improve the fuel economy of passenger cars, it is clear that reduction of ancillary loads plays a key role for achieving significant fuel consumption and emissions reductions. In a conventional passenger vehicle, the A/C system is the largest ancillary load and it has been shown that it can consume up to 9% of the engine power available at the crankshaft This paper approaches the problem of reducing the parasitic load of the A/C system as a multi-objective optimization problem. Starting from a validated control-oriented model of an automotive A/C system, an optimization problem is formalized. Specifically, the objective of the optimization is to achieve the best possible fuel economy over a driving cycle, while guaranteeing the passenger comfort in terms of cabin temperature and reduce the wear of the components, in this case the compressor clutch.
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