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Viewing 211 to 240 of 10387
2016-04-05
Journal Article
2016-01-1404
Steven E. Hodges
Abstract Fire protection, active and passive, has been, and is, an important area of concern during the design, development and deployment phases for all modern ground vehicles. All US military vehicles carry handheld fire extinguishers, and many tactical and all combat vehicles have automatic fire protection systems that protect the crew, engine, and in some cases, external components such as fuel tanks and wheels, from potentially catastrophic combat events involving fire. Vehicle designs also mitigate fire hazards by separating the vehicle occupants from the most flammable materials, e.g., fuel and ammunition, as much as practical. Explosion protection of the crew and passengers in military vehicles is a unique application with unique requirements that must balance suppression actions with safety limits.
2016-04-05
Journal Article
2016-01-0233
Masayoshi Mori, Manabu Matsumoto, Makoto Ohtani
Abstract The practical application of heat recovery using thermoelectrics requires the realization of reasonable cost effectiveness. Therefore, a thermoelectric generator (TEG) structure that can compatibly increase efficiency and reduce cost was investigated with the aim of enhancing cost effectiveness. To increase efficiency, a method of using a vacuum space structure to reduce the TEG size was investigated to enable installation just after the close-coupled catalyzer, which is subject to many space restrictions. It was found that by making it possible to use high temperature exhaust heat, power generation efficiency can be increased to approximately twice that of the typical under floor installation. In addition, coupled simulation of heat transfer and power generation using FEM, 1D cost effectiveness simulations, and bench tests were performed with the aim of reducing cost.
2016-04-05
Journal Article
2016-01-0236
Forrest Jehlik, Eric Rask, Michael Duoba
Abstract It is widely understood that cold ambient temperatures negatively impact vehicle system efficiency. This is due to a combination of factors: increased friction (engine oil, transmission, and driveline viscous effects), cold start enrichment, heat transfer, and air density variations. Although the science of quantifying steady-state vehicle component efficiency is mature, transient component efficiencies over dynamic ambient real-world conditions is less understood and quantified. This work characterizes wheel assembly efficiencies of a conventional and electric vehicle over a wide range of ambient conditions. For this work, the wheel assembly is defined as the tire side axle spline, spline housing, bearings, brakes, and tires. Dynamometer testing over hot and cold ambient temperatures was conducted with a conventional and electric vehicle instrumented to determine the output energy losses of the wheel assembly in proportion to the input energy of the half-shafts.
2016-04-05
Journal Article
2016-01-0238
Gang Liu, Zheng Zhao, Hao Guan, Yaqi Liu, Chunhui Zhang, Dingwei Gao, Wuming Zhou, Juergen Knauf
Abstract Reducing fuel consumption is a major challenge for vehicle, especially for SUV. Cooling loss is about 30% in total energy loss under NEDC (New European Driving Cycle) cycle. It is necessary to optimize vehicle thermal management system to improve fuel economy. Otherwise, rapid warm-up is beneficial for friction reduction and passenger comfort in cold-start. Vehicle thermal behavior is influenced by cooling system layout, new technology and control strategy. Thermal management simulation is effective to show the energy flow and fuel consumption under the influence of new technology under NEDC cycle. So 1D thermal management simulation model is created, including vehicle, cooling system, lubrication system and detailed engine model with all friction components. And the interrelations between all the components are considered in the model.
2016-04-05
Journal Article
2016-01-0243
Jingwei Zhu, Stefan Elbel
Abstract Expansion work recovery by two-phase ejector is known to be beneficial to vapor compression cycle performance. However, one of the biggest challenges with ejector vapor compression cycles is that the ejector cycle performance is sensitive to working condition changes which are common in automotive applications. Different working conditions require different ejector geometries to achieve maximum performance. Slightly different geometries may result in substantially different COPs under the same conditions. The ejector motive nozzle throat diameter (motive nozzle restrictiveness) is one of the key parameters that can significantly affect ejector cycle COP. This paper presents a new two-phase nozzle restrictiveness control mechanism which is possibly applicable to two-phase ejectors used in vapor compression cycles.
2016-04-05
Journal Article
2016-01-0258
Jason Aaron Lustbader, Bidzina Kekelia, Jeff Tomerlin, Cory J. Kreutzer, Skip Yeakel, Steven Adelman, Zhiming Luo, John Zehme
Abstract Annual fuel use for sleeper cab truck rest period idling is estimated at 667 million gallons in the United States, or 6.8% of long-haul truck fuel use. Truck idling during a rest period represents zero freight efficiency and is largely done to supply accessory power for climate conditioning of the cab. The National Renewable Energy Laboratory’s CoolCab project aims to reduce heating, ventilating, and air conditioning (HVAC) loads and resulting fuel use from rest period idling by working closely with industry to design efficient long-haul truck thermal management systems while maintaining occupant comfort. Enhancing the thermal performance of cab/sleepers will enable smaller, lighter, and more cost-effective idle reduction solutions. In addition, if the fuel savings provide a one- to three-year payback period, fleet owners will be economically motivated to incorporate them.
2016-04-05
Journal Article
2016-01-0251
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
Journal Article
2016-01-0261
Lili Feng, Predrag Hrnjak
Abstract This paper presents a simulation model for a reversible air conditioning and heat pump system for electric vehicles. The system contains a variable speed compressor, three microchannel heat exchangers, an accumulator, and two electronic expansion valves. Heat exchangers are solved by discretizing into cells. Compressor and accumulator models are developed by fitting data with physical insights. Expansion valves are modeled by isenthalpic processes. System performance is calculated by connecting all parts in the same way as the physical system and solved iteratively. The model is reasonably validated against experimental data from a separate experimental study. Future improvement is needed to take into account maldistribution in outdoor heat exchanger working as an evaporator in HP mode. Charge retention in components also requires further study.
2016-04-05
Journal Article
2016-01-0262
Matthew A. Jeffers, Larry Chaney, John P. Rugh
Abstract When operated, the cabin climate control system is the largest auxiliary load on a vehicle. This load has significant impact on fuel economy for conventional and hybrid vehicles, and it drastically reduces the driving range of all-electric vehicles (EVs). Heating is even more detrimental to EV range than cooling because no engine waste heat is available. Reducing the thermal loads on the vehicle climate control system will extend driving range and increase the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have evaluated strategies for vehicle climate control load reduction with special attention toward grid-connected electric vehicles. Outdoor vehicle thermal testing and computational modeling were used to assess potential strategies for improved thermal management and to evaluate the effectiveness of thermal load reduction technologies. A human physiology model was also used to evaluate the impact on occupant thermal comfort.
2016-04-05
Journal Article
2016-01-1304
Tadayoshi Fukushima, Hitoshi Takagi, Toshio Enomoto, Hiroyuki Sawada, Tomoyuki Kaneda
Abstract Interior noise caused by exterior air flow, or wind noise, is one of the noise-and-vibration phenomena for which a systematic simulation method has been desired for enabling their prediction. One of the main difficulties in simulating wind noise is that, unlike most other noises from the engine or road input, wind noise has not one but two different types of sources, namely, convective and acoustic ones. Therefore, in order to synthesize the interior sound pressure level (SPL), the body sensitivities (interior SPL/outer source level) for both types of sources have to be considered. In particular, sensitivity to the convective input has not been well understood, and hence it has not been determined. Moreover, the high-frequency nature of wind noise (e.g., the main energy range extends up to 4000 Hz) has limited the effective application of CAE for determining body sensitivities, for example, from the side window glass to the occupants’ ears.
2016-04-05
Journal Article
2016-01-1402
Jeffrey Hurlbut, Daniel Cashen, Emily Robb, Lora L. Spangler, Jim Eckhart
Abstract Head-up display (HUD) technology creates inherent driver safety advantages by displaying critical information directly in the driver’s line of sight, reducing eyes off road and accommodation time. This is accomplished using a system of relay optics and windshield reflection to generate a virtual image that appears to hover over the hood near the bumper. The windshield is an integral optical component of the HUD system, but unfortunately the windshield-air interface causes a double image ghost effect as a result of refractive index change, reducing HUD image clarity. Current technology uses a constant angle wedged PVB windshield interlayer to eliminate double image at a single driver height. However, the HUD double image persists for all other viewing locations. Eastman Chemical Company has developed a new interlayer technology which eliminates the double image at all driver locations by tuning the wedge angle as a function of driver occupant seated height.
2016-04-05
Technical Paper
2016-01-1482
Paul Montalbano, Daniel Melcher, Rachel Keller, Thomas Rush, Jay Przybyla
Abstract A number of methods have been presented previously in the literature for determination of the impact speed of a motorcycle or scooter at its point of contact with another, typically larger and heavier, vehicle or object. However, all introduced methods to date have known limitations, especially as there are often significant challenges in gathering the needed data after a collision. Unlike passenger vehicles and commercial vehicles, most motorcycles and scooters carry no onboard electronic data recorders to provide insight into the impact phase of the collision. Recent research into automobile speedometers has shown that certain types of modern stepper motor based speedometers and tachometers can provide useful data for a collision reconstruction analysis if the instrument cluster loses electrical power during the impact, resulting in a “frozen” needle indication.
2016-04-05
Technical Paper
2016-01-1435
Amber Hall, Michael Kolich
Abstract Many studies have been conducted and supporting literature has been published to better understand thermal comfort for the automotive environment, particularly, for the HVAC system within the cabin. However, reliable assessment of occupant thermal comfort for seating systems has lacked in development and understanding. Evaluation of seat system performance in terms of comfort has been difficult to quantify and thus most tests have been established such that the hardware components are tested to determine if the thermal feature does no harm to the customer. This paper evaluates the optimal seat surface temperature range to optimize human thermal comfort for an automotive seating system application for heated and ventilated seats.
2016-04-05
Journal Article
2016-01-0656
Jung Hyun Kim, Taewoo Kim, SungJin Park, JungJae Han, Choongsoo Jung, Young rock Chung, Sangsoo Pae
Abstract In cold start driving cycles, high viscosity of the lubrication oil (engine oil) increases the mechanical friction losses compared with warmed up condition. Thus, an engine oil warm up system can provide the opportunity to reduce the mechanical friction losses during cold start. In this study, an engine oil heater using EGR is used for the fast warm up of the engine oil. This paper presents the effect of the engine oil heater on the fuel economy and emissions over a driving cycle (NEDC). A numerical model is developed to simulate the thermal response of the powertrain using multi-domain 1-D commercial powertrain simulation software (GT-Suite) and it is calibrated using test data from a full size sedan equipped with a 2.0L diesel engine. The model consists of an engine model, coolant circuit model, oil circuit model, engine cooling model, friction model, and ECU model.
2016-04-05
Journal Article
2016-01-0661
Yoshifumi Wakisaka, Minaji Inayoshi, Kenji Fukui, Hidemasa Kosaka, Yoshihiro Hotta, Akio Kawaguchi, Noriyuki Takada
The reduction of the heat loss from the in-cylinder gas to the combustion chamber wall is one of the key technologies for improving the thermal efficiency of internal combustion engines. This paper describes an experimental verification of the “temperature swing” insulation concept, whereby the surface temperature of the combustion chamber wall follows that of the transient gas. First, we focus on the development of “temperature swing” insulation materials and structures with the thermo-physical properties of low thermal conductivity and low volumetric heat capacity. Heat flux measurements for the developed insulation coating show that a new insulation material formed from silica-reinforced porous anodized aluminum (SiRPA) offers both heat-rejecting properties and reliability in an internal combustion engine. Furthermore, a laser-induced phosphorescence technique was used to verify the temporal changes in the surface temperature of the developed insulation coating.
2016-04-05
Journal Article
2016-01-0729
Takeshi Okamoto, Noboru Uchida
Abstract To overcome the trade-offs of thermal efficiency with energy loss and exhaust emissions typical of conventional diesel engines, a new diffusion-combustion-based concept with multiple fuel injectors has been developed. This engine employs neither low temperature combustion nor homogeneous charge compression ignition combustion. One injector was mounted vertically at the cylinder center like in a conventional direct injection diesel engine, and two additional injectors were slant-mounted at the piston cavity circumference. The sprays from the side injectors were directed along the swirl direction to prevent both spray interference and spray impingement on the cavity wall, while improving air utilization near the center of the cavity.
2016-04-05
Journal Article
2016-01-0084
Paul Weindorf, James Krier, Carl Evans
Abstract An optical configuration has been developed which offers a seamless appearance where the display aperture is less visible in the “off” condition and is minimized in the “on” condition.
2016-04-05
Journal Article
2016-01-0310
Xinran Tao, John R. Wagner
Abstract The pursuit of greater fuel economy in internal combustion engines requires the optimization of all subsystems including thermal management. The reduction of cooling power required by the electromechanical coolant pump, radiator fan(s), and thermal valve demands real time control strategies. To maintain the engine temperature within prescribed limits for different operating conditions, the continual estimation of the heat removal needs and the synergistic operation of the cooling system components must be accomplished. The reductions in thermal management power consumption can be achieved by avoiding unnecessary overcooling efforts which are often accommodated by extreme thermostat valve positions. In this paper, an optimal nonlinear controller for a military M-ATV engine cooling system will be presented. The prescribed engine coolant temperature will be tracked while minimizing the pump, fan(s), and valve power usage.
2016-04-05
Journal Article
2016-01-0309
Matthew Reed, Sheila Ebert-Hamilton
Abstract This study evaluated the ISO 5353 Seat Index Point Tool (SIPT) as an alternative to the SAE J826 H-point manikin for measuring military seats. A tool was fabricated based on the ISO specification and a custom back-angle measurement probe was designed and fitted to the SIPT. Comparisons between the two tools in a wide range of seating conditions showed that the mean SIP location was 5 mm aft of the H-point, with a standard deviation of 7.8 mm. Vertical location was not significantly different between the two tools (mean - 0.7 mm, sd 4.0 mm). A high correlation (r=0.9) was observed between the back angle measurements from the two tools. The SIPT was slightly more repeatable across installations and installers than the J826 manikin, with most of the discrepancy arising from situations with flat seat cushion angles and either unusually upright or reclined back angles that caused the J826 manikin to be unstable.
2016-04-05
Journal Article
2016-01-1273
Lakshmikanth Meda, Martin Romzek, Yanliang Zhang, Martin Cleary
Abstract Although the technology of combustion engines is reasonably well developed, the degree of efficiency is considerably low. Considerable amount of the energy of around 35 % is lost as exhaust waste heat, and up to 30 % is dissipated in the cooling circuits. Due to this, thermal recuperation has a great potential for raising the efficiency of combustion engines. In order to meet the ever-increasing consumer demand for higher fuel economy, and to conform to more stringent governmental regulations, auto manufacturers have increasingly looked at thermoelectric materials as a potential method to recover some of that waste heat and improve the overall efficiency of their vehicle fleets. Seeking new possibilities to make vehicles greener and more efficient, the industry wants to use the waste heat which passes through the exhaust system almost completely unused in the past.
2016-03-27
Technical Paper
2016-01-1732
Weicheng Huang
Abstract When the vehicle parks in direct sunlight conditions, the cabin will form a high-temperature thermal environment in hot weather. Drivers would turn on the air-conditioning with relatively high gear in the most conditions to reduce the cabin temperature, which could affect the life of equipment, resulting in energy waste and increasing emissions. This study adopted solar energy in the ventilation system. When the car parks the cabin blower was driven by a solar panel mounted on the car roof to discharge heat inside the cabin real time, achieving the purpose of pre-cooling. Firstly, heat transfer model and ventilation cooling model for the cabin were established according to the theory of heat transfer, and models were modified through experiments. Besides, the impact of ventilation flow rate on the pre-cooling effect was studied based on simulation analysis.
2016-03-25
WIP Standard
AIR5661A
This report provides data and general analysis methods for calculation of internal and external, pressurized and unpressurized airplane compartment pressures during rapid discharge of cabin pressure. References to the applicable current FAA and EASA rules and advisory material are provided. While rules and interpretations can be expected to evolve, numerous airplanes have been approved under current and past rules that will have a continuing need for analysis of production and field modifications, alterations and repairs. The data and basic principles provided by this report are adaptable to any compartment decompression analysis requirement.
2016-03-23
WIP Standard
J2230
This SAE Standard specifies operating procedure for the exposure of automotive interior trim materials in an outdoor behind-glass apparatus in which the temperature is controlled in a 24 h cycle. The humidity is controlled during the dark (night) portion of the cycle. Specimen preparation, test durations, and performance evaluation procedures are covered in material specifications of the different automotive manufacturers.
2016-03-19
Article
An "electronic assistant" with the capability to determine if the driver is capable of receiving information under safety critical conditions.
2016-03-16
Standard
AS50571B
This specification covers the general requirements for red and white individual instrument lights. This document has been streamlined. Appendix A to MIL-L-5057F lists those documents required for MIL-L-5057F acquisition and is a mandatory part of MIL-L-5057F. Those documents listed in Appendix A have the same status as those referenced directly in MIL-L-5057F (first tier documents). All other documents, referenced through tiering, may be used as guidance and information to supplement MIL-L-5057F. This document’s scope is limited to lamp source designs solely. Furthermore, the use of red lighting should not be considered for new design and included within this document to support requirements for existing military aircraft that still operate with this system of lighting.
2016-03-16
WIP Standard
AS1046D
This standard is intended to apply to portable compressed gaseous oxygen equipment. When properly configured, this equipment is used either for the administration of supplemental oxygen, first aid oxygen or smoke protection to one or more occupants of either private or commercial transport aircraft.
2016-03-16
Standard
AS6296
This SAE Aerospace Standard (AS) specifies minimum performance standards for Electronic Flight Information System (EFIS) displays that are head-down and intended for use in the flight deck by the flight crew in all 14 CFR Part 23, 25, 27, and 29 aircraft. This document is expected to be used by multiple regulatory agencies as the basic requirement for a technical standard order for EFIS displays. The requirements and recommendations in this document are intended to apply to, but are not limited to, the following types of display functions: Primary Flight and Primary Navigation displays, including vertical situation and horizontal situation functions. Displays that provide flight crew alerts, which may include engine instrument, aircraft systems information/control. Control displays including communication, navigation and system control displays.
2016-03-14
Journal Article
2016-01-9107
Jan Christoph Menken, Martin Ricke, Thomas A. Weustenfeld, Juergen Koehler
Abstract Recent attempts to find energy-efficient thermal management systems for electric and plug-in hybrid electric vehicles have led to secondary loop systems as an alternative approach to meet dynamic heating and cooling demands and to reduce refrigerant charge. The choice of refrigerant for the primary refrigeration cycle is an important issue regarding the overall system performance. In this work, an HFC refrigerant (R-134a) and a natural refrigerant (R-744) are evaluated regarding a potential use in secondary loop systems. To meet the demands of R-744 cycles such as higher system pressure, most components have to be redeveloped. Nonetheless the use of the environmentally friendly refrigerant has advantages such as better applicability and performance in heat pump systems under cold ambient conditions.
2016-03-12
Article
Jeep Design is taking seven new concept vehicles, including two interesting pickups, to the Utah off-road festival where the hardest-core Jeep enthusiasts gather annually.
2016-03-11
Standard
J2810_201603
The purpose of this SAE Standard is to provide minimum performance and operating feature requirements for the recovery of HFC-134a (R-134a) refrigerant to be returned to a refrigerant reclamation facility that will process it to the appropriate AHRI 700 Standard or allow for on-site recycling of the recovered refrigerant to SAE J2788 specifications by using SAE J2788 or SAE J3030 -certified equipment. It is not acceptable that the refrigerant removed from a mobile air-conditioning (A/C) system with this equipment be directly returned to a mobile A/C system. An identifier certified to SAE J2912 is to be used to identify the contents of the system prior to recovery of the refrigerant.
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