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Viewing 121 to 150 of 39471
2011-04-12
Technical Paper
2011-01-1054
Ram S. Iyer, Timothy Montroy, Shawn Morgans, Kevin Gustafson
The front bumper of a current production vehicle, which is made of hot-stamped 15B21 aluminized steel, was studied for mass and cost reductions using the Advanced High Strength Stainless Steel product NITRONIC® 30 (UNS Designation S20400) manufactured by AK Steel Corporation. This grade of stainless steel offers a combination of high ductility and strength, which was utilized to significantly modify the design of the bumper beam to incorporate geometry changes that improved its stiffness and strength. The structural performance of the bumper assembly was evaluated using LS-Dyna-based CAE simulations of the IIHS 40% Offset Full-Vehicle Impact at 40 mph with a deformable barrier, and the IIHS Full Width Centerline 6 mph Low-Speed Impact. Optimization of the bumper beam shape and gauge was performed using a combination of manual design iterations and a multi-objective optimization methodology using LS-Opt.
2011-04-12
Technical Paper
2011-01-1056
Katsuya Hoshino, Shoichiro Taira, Naoto Yoshimi, Yuji Yamasaki, Kazuhiko Higai, Masayasu Nagoshi, Yoshiharu Sugimoto
Since galvannealed steel sheets (GA) are widely used for automobile body parts, they require excellent features such as press formability, resistant spot weldability and phosphatability. We have focused on improving the press formability of GA since the late 1990s, and have developed a new type of surface modified GA which has a lower friction coefficient than conventional GA. The developed surface modified GA based on mild steel is now used by all automakers in Japan, especially for those parts such as side panels that are difficult to form. This paper describes the features of the surface modified GA.
2011-04-12
Technical Paper
2011-01-1055
Z.Connie Yao, Rong Zhang, Gary C. Barber
As high strength steels are introduced into automotive stamping applications to satisfy CAFE (Corporate Average Fuel Economy) and fuel economy requirements, wear of stamping dies is becoming a major issue. Many types of coatings/surface treatments such as: thermal spray, ion nitriding, chrome plating, PVD, CVD, and TD coatings are being used. Choosing the best coating is difficult since there is little data available to compare all types of coatings under the same operating conditions. A laboratory pin on flat test procedure was developed and utilized to compare the wear resistance of various coatings. SEM pictures of wear scars of coated pins indicated that coatings can effectively protect the substrate material from wear. Without coating the substrate material wears away rapidly. The test results showed that hard chrome performed well when run against various sheet materials, but its wear resistance was significantly lower than high temperature coatings.
2011-04-12
Technical Paper
2011-01-1062
Andrey Ilinich, Lorenzo Smith, Sergey Golovashchenko
Imposing tensile stress on an edge of a sheet metal blank is a common condition in many sheet metal forming operations, making edge formability a very important factor to consider. Because edge formability varies greatly among different materials, cutting methods (and their control parameters), it is very important to have access to an experimental technique that would allow for quick and reliable evaluation of edge formability for a given case. In this paper, two existing techniques are compared: the hole expansion test and the tensile test. It is shown that the hole expansion test might not be adequate for many cases, and is prone to overestimating the limiting strain, because the burr on the sheared edge is typically smaller than what is observed in production. The tensile test represents an effective alternative to the hole expansion test. Advantages and disadvantages of each case are discussed.
2011-04-12
Technical Paper
2011-01-1061
Timo Faath, Paul McKune, Markus Weber
The ThyssenKrupp InCar Project is a comprehensive R&D development that gives automotive manufacturers modular solution kits for body, chassis, and powertrain applications. The solution kits developed within this project offer weight reduction, cost savings, or improved functionality. This paper will focus on the front longitudinal members of the body structure. The front longitudinal member is a key safety component responsible for absorbing energy in a frontal crash event. It must also have high local strength, stiffness, and fatigue resistance at the suspension attachment points. Within the InCar project, several different solutions for the front longitudinal members were developed, including stamped AHSS concepts, stamped AHSS tailored blank concepts, and tailored tube concepts using an innovative forming technology for closed section designs, called InForm T3 (Thyssen Tailored Tubes).
2011-04-12
Technical Paper
2011-01-1078
Arun M. Joshi, Hesham Ezzat, Norman Bucknor, Mark Verbrugge
In designing vehicles with significant electric driving range, optimizing vehicle energy efficiency is a key requirement to maximize the limited energy capacity of the onboard electrochemical energy storage system. A critical factor in vehicle energy efficiency is the vehicle mass. Optimizing mass allows for the possibility of either increasing electric driving range with a constant level of electrochemical energy storage or holding the range constant while reducing the level of energy storage, thus reducing storage cost. In this paper, a methodology is outlined to study the tradeoff between the battery cost savings achieved by vehicle mass reduction for a constant electric driving range and the cost associated with lightweighting a vehicle. This methodology enables informed business decisions about the available engineering options for lightweighting early in the vehicle development process. The methodology was applied to a compact extended-range electric vehicle (EREV) concept.
2011-04-12
Journal Article
2011-01-1076
Randy Gu, Leonid C. Lev, Lianxiang Yang
In this paper, a finite element methodology is given in which finite element models of a three-weld Al-Cu plate is created with support and loading conditions emulating those seen in an optical lab. Harmonic response is sought for the models under the presumption that various defective welds are present. The numerical results are carefully examined to determine the guideline frequency range so the actual optical experiment can be carried out more efficiently.
2011-04-12
Technical Paper
2011-01-1085
Douglas Rourke
Many new surface finishes have been proposed for zinc die casting. In many cases these are intended to replace the traditional processes of solvent-based painting, electroplating and hexavalent chromium. Twenty new coatings were offered by suppliers and were subjected to cyclic corrosion testing (CCT). A wide variation in results was seen, suggesting the need for further development in come cases. However, several of the new environmentally friendly finishes are of interest for current application.
2011-04-12
Technical Paper
2011-01-1086
Keith Zhang, Artur Filc
A new high fluidity zinc die cast alloy was developed at Teck Metals' Product Technology Centre. This hot chamber die cast alloy is based on the commonly used ZAMAK alloys but possesses up to 40% better fluidity. Industrial trials and evaluations have confirmed the excellent fluidity of the alloy as well as the easy use and adoption of the alloy. Tests have shown the alloy has comparable physical, mechanical and corrosion properties as Alloy 3 and 7. The alloy is best suited to be used for casting parts with section thickness less than 0.45 mm. It can also be used for casting parts that are difficult to fill or have high surface finish requirement.
2011-04-12
Technical Paper
2011-01-1083
Steve Dawson
The demands for improved fuel economy, performance and emissions continue to pose challenges for engine designers and the materials they choose. The present paper provides a review of the properties of Compacted Graphite Iron (CGI), gray cast iron and aluminum and shows how the superior mechanical properties of CGI can contribute to engine design and performance. Based on production experience in Europe, Asia and the Americas, the application of CGI can provide new opportunities for reductions in engine weight and package size, increased specific performance together with improved durability, and improved NVH. Despite the density difference between CGI and aluminum, the ability to make a more compact cylinder block when using CGI often results in a fully assembled CGI engines that weigh less than an aluminum engines of the same displacement. This design opportunity is illustrated with specific examples of V6 and V8 diesel engines that are currently in production.
2011-04-12
Technical Paper
2011-01-1084
Ryan Winter
Progress in recent alloy development work has resulted in the commercialization of a high strength, creep resistant, hot chamber zinc based die casting alloy. The work was based upon earlier research conducted under the sponsorship of the Department of Energy Cast Materials Consortium (CMC). Refinement of alloy chemistry produced significant improvements in tensile strength, hardness and creep performance. Because the composition of this new alloy is near that of the Aluminum/Copper/Zinc ternary eutectic, the low melting temperature enables the alloy to be cast in a hot chamber die casting machine without excessive wear of shot end components typically experienced with other high-copper zinc die casting alloys contents such as ACuZinc 5.
2011-04-12
Journal Article
2011-01-1082
Frank E. Goodwin, Lothar Kallien
Most creep studies are conducted to determine steady state creep rate and time to failure. However, the priority for the designer is to predict the amount of total creep, being the sum of primary and secondary creep elongations, for a given service life under given loads and temperatures, for example 0.5% elongation after 3000h. An assessment of total creep behavior of industrially important zinc alloys has been conducted, and correlation/prediction curves produced. Another important property, related to creep, is stability after ageing, both for unloaded and also loaded castings. Recently developed relationships between natural and artificial ageing, and the correlation of mechanical property changes for different periods of artificial ageing with natural ageing will be presented.
2011-04-12
Technical Paper
2011-01-1091
Jiman Han, Gary Barber, Qian Zou, Xichen Sun, Philip Seaton
Scuffing is one of the major problems that influence the life cycle and reliability of several auto components, including engine cylinder kits, flywheels, camshafts, crankshafts, and gears. Ferrous casting materials, such as gray cast iron, ductile cast iron and austempered ductile cast iron (ADI) are widely applied in these components due to their self-lubricating characteristics. The purpose of this research is to determine the scuffing behavior of these three types of cast iron materials and compare them with 1050 steel. Rotational ball-on-disc tests were conducted with white mineral oil as the lubricant under variable sliding speeds and loads. The results indicate that the scuffing initiation is due to either crack propagation or plastic deformation. It is found that ADI exhibits the highest scuffing resistance among these materials.
2011-04-12
Technical Paper
2011-01-1090
Mark E. DeBruin, S. Jordan
Despite the embrace of aluminum and other nonferrous materials, steel is still a widely used material in the vehicle industry. However, it is not produced in the vehicle industry by the lost foam casting (LFC) method despite the tremendous potential benefits. These include the elimination of machining due to tolerances equal to investment casting and part consolidation which allows for the elimination of components and joining technologies. Both of these are financially and operationally beneficial by allowing for the creation of a leaner supply chain. With proper lost foam casting technology adjustments to compensate for the higher melting point of steel, there appear to be no degradation in cast steel as compared to when cast by green sand or resin bonded sand (no -bake) methods. In fact the opposite is true as the LFC benefits of improved surface roughness and dimensionality are maintained.
2011-04-12
Technical Paper
2011-01-1089
Ehab Samuel, Michel Garat, Fred Major
Cast aluminum-silicon alloys have witnessed a notable increase in use in the automotive and transport industry. The ability of these alloys to be easily cast into complex shapes coupled with a favorable strength-to-weight ratio has given them an edge over cast irons. One particular area of casting which has received further and further attention is the area of semi-solid casting, where an alloy casting is prepared as slurry with flow properties that resemble both solid and liquid. In the present work, the effects of iron additions on the mechanical properties of a 319 semi-solid alloy were studied. This alloy was prepared using the SEED process, as developed by Rio Tinto Alcan in collaboration with the Aluminum Technology Centre of NRC Canada. The SEED (Swirled Enthalpy Equilibration Device) process is a novel rheocasting method which yields a semi-solid slurry from the mechanical stirring and cooling of the molten aluminum.
2011-04-12
Technical Paper
2011-01-1088
Frank E. Goodwin, Martin Gagné
Alloy 3, Alloy 5, ACuZinc 5, and ZA-8 were tested at five temperatures between −40 C and room temperature to determine impact properties. Izod impact energy data was obtained in accordance with ASTM D256. Unlike ASTM E23, these samples were tested with a milled notch in order to compare with plastic samples. In addition, flexural data was obtained for design use. Fatigue stress-life (S-N) curves and fatigue limits of die cast zinc Alloy 2, Alloy 3, Alloy 5, ACuZinc 5, and ZA-8 were determined using the rotating bend test. Fatigue limits for Alloy 3, Alloy 5, and ACuZinc 5 appeared to be higher and the fatigue limit for ZA-8 appeared to be lower than the values reported in the literature. The improvement in properties for Alloy 3, Alloy 5 and ACuZinc 5 is related to the presence of the die cast skin.
2011-04-12
Technical Paper
2011-01-1087
Martin Gagné
Zinc die casting products and metal casting processes continue to evolve for the benefit of end users. Through cooperative global research programs continuous improvements are still being made to the broad range of excellent mechanical properties, easy castability and the wide choice of finishes available for zinc die castings. Recent advances will be highlighted with case histories specific to automotive applications.
2011-04-12
Technical Paper
2011-01-1119
Sandeep Chandrakant Kulkarni, Matthew Marks
An automobile is designed to meet numerous impact events, including frontal impact, side impact, rear impact, and roll over. Roof crush resistance is a test defined by Federal Motor Vehicle Safety Standard (FMVSS) 216. The intent of this test is to evaluate the strength of the roof and supporting body structure during a vehicle rollover. Steel countermeasures are typically used as structural-reinforcing elements to the body structure to improve the crush strength of a vehicle roof. This paper presents a thermoplastic countermeasure (CM) design as a light-weight solution to replace traditional steel countermeasures. Two concepts are discussed in the paper: an all-plastic countermeasure and a plastic/metal hybrid countermeasure consisting of stamped steel with a thermoplastic reinforcing rib structure. Finite Element (FE) methods using LS-DYNA are used to evaluate the performance of these countermeasure concepts.
2011-04-12
Technical Paper
2011-01-1207
Wim Van Dam, Mark W. Cooper, Kenneth Oxorn, Scott Richards
Since the invention of the internal combustion engine, the contact between piston ring and cylinder liner has been a major concern for engine builders. The quality and durability of this contact has been linked to the life of the engine, its maintenance, and its exhaust gas and blowby emissions, but also to its factional properties and therefore fuel economy. While the basic design has not changed, many factors that affect the performance of the ring/liner contact have evolved and are still evolving. This paper provides an overview of observations related to the lubrication of the ring/liner contact.
2011-04-12
Technical Paper
2011-01-1192
Anand Kumar Pandey, Milankumar Nandgaonkar
Karanja biodiesel is prepared using Karanja oil and methanol by the process of transesterification. Use of Karanja oil methyl ester (KOME) in a 780 hp CIDI military engine was found to be a highly compatible alternative fuel with low emission characteristics. Engine was operated for 100 hours each using pure karanja biodiesel and mineral diesel fuel, respectively. These were subjected to long-term endurance tests. Lubricating oil samples, drawn from both fuelled engine after a fixed interval of 20 hours, were subjected to elemental analysis. Atomic absorption spectroscopy (AAS) was done for quantification of various metal debris concentrations. Wear metals were found lower for a biodiesel operated engine system. Lubricating oil samples were also subjected to ferrography indicating lower wear debris concentrations for a biodiesel-operated engine. Scanning electron microscopy was also conducted on the cylinder liner surfaces exposed to wear.
2011-04-12
Technical Paper
2011-01-1190
Haifeng Liu, Chia-Fon Lee, Yu Liu, MIng Huo, Mingfa Yao
A very competitive alcohol for use in diesel engines is butanol. Butanol is of particular interest as a renewable bio-fuel, as it is less hydrophilic and it possesses higher heating value, higher cetane number, lower vapor pressure, and higher miscibility than ethanol or methanol. These properties make butanol preferable to ethanol or methanol for blending with conventional diesel or gasoline fuel. In this paper, the spray and combustion characteristics of pure n-butanol fuel was experimentally investigated in a constant volume combustion chamber. The ambient temperatures were set to 1000 K, and three different oxygen concentrations were set to 21%, 16%, and 10.5%. The results indicate that the penetration length reduces with the increase of ambient oxygen concentration. The combustion pressure and heat release rate demonstrate the auto-ignition delay becomes longer with decreasing of oxygen concentrations.
2013-04-08
Journal Article
2013-01-1508
Huize Li, Predrag Hrnjak
This paper presents a model analysis of oil effects on the distribution of two phase refrigerant in a parallel flow microchannel evaporator. A microchannel evaporator model developed and presented earlier (SAE paper 2012-01-0321) is enhanced by inclusion of the thermodynamic and transport properties of refrigerant-oil mixture and their impact on boiling heat transfer and pressure drop characteristics. R134a and PAG oil are selected as the working pair. Viscosity effect and OCR effect on refrigerant distribution are investigated using this model, and the results show that 1) High viscosity is detrimental for refrigerant distribution. 2) As OCR increases, distribution becomes worse; but at very high OCR, distribution becomes better. Some initial experimental results show that distribution becomes worse when OCR changes from 0.1% to 3%.
2013-04-08
Journal Article
2013-01-1504
Lothar Seybold, William Hill, Ioannis Lazaridis
The United States Environmental Protection Agency (EPA) as well as the European Commission (EC) are developing test procedures to regulate mobile air conditioning system (MAC) efficiency to reduce greenhouse gas emissions and reduce global warming. In the United States, air conditioning related MAC credits can be earned by implementing an internal heat exchanger (IHX) into a MAC system. By integrating an IHX into a MAC system the, Coefficient of Performance (COP) can be increased at the same time increasing cooling capacity. This improvement in efficiency reduces the energy and/or fuel consumption of the MAC system. This paper will compare various IHX plumbing configurations for a dual evaporator system with R1234yf refrigerant. A MAC system optimized for efficiency as well as evaporator cooling capacity is used to assess these different IHX plumbing configurations.
2013-04-08
Technical Paper
2013-01-1502
Shankar Natarajan, Sathish Kumar S, Ricardo Amaral, Sadek Rahman
Simulation has become an integral part in the design and development of an automotive air-conditioning (AC) system. Simulation is widely used for both system level and component level analyses and are carried out with one-dimensional (1D) and Computational Fluid Dynamics (CFD) tools. This paper describes a 1D approach to model refrigerant loop and vehicle cabin to simulate the soak and cool down analysis. Soak and cool down is one of the important tests that is carried out to test the performance of a heating, ventilation and air-conditioning (HVAC) system of a vehicle. Ability to simulate this cool down cycle is thus very useful. 1D modeling is done for the two-phase flow through the refrigerant loop and air flow across the heat exchangers and cabin with the commercial software AMESim. The model is able to predict refrigerant pressure and temperature inside the loop at different points in the cycle.
2013-04-08
Technical Paper
2013-01-1503
Sathish Kumar S, Shankar Natarajan, Michael V Rinaldi
In an automotive air-conditioning (AC) system, the amount of work done by the compressor is also influenced by the suction line which meters the refrigerant flow. Optimizing the AC suction line routing has thus become an important challenge and the plumbing designers are required to come up with innovative packaging solutions. These solutions are required in the early design stages when prototypes are not yet appropriate. In such scenarios, one-dimensional (1D) simulations shall be employed to compute the pressure drop for faster and economical solution. In this paper, an approach of creating a modeling tool for suction line pressure drop prediction is discussed. Using DFSS approach L12 design iterations are created and simulations are carried out using 1D AMESim software. Prototypes are manufactured and tested on HVAC bench calorimeter. AC suction line pressure drop predicted using the 1D modeling co-related well with the test data and the error is less than 5%.
2013-04-08
Journal Article
2013-01-1500
Hanfei Tuo, Predrag Hrnjak
This paper presents experimental study of periodic reverse flow and induced boiling fluctuations in a microchannel evaporator and their impacts on performance of R134a mobile A/C system. Simultaneous flow visualization and pressure measurements revealed that reverse flow due to confined bubble longitudinal expansion caused periodic oscillations of the evaporator inlet pressure and the pressure drop, and their oscillation magnitude and frequency increase with ambient air temperatures because of higher average refrigerant mass flux and heat flux. Three potential impacts of vapor reverse flow reversal on evaporator performance are identified: 1) mild liquid maldistribution; 2) increased the evaporator pressure drop; 3) reduced heat transfer coefficient. Finally, to mitigate vapor reverse flow impacts, revised flash gas bypass (FGBR) method is proposed: vent and bypass backflow vapor trapped in the inlet header.
2013-04-08
Technical Paper
2013-01-1495
Neal Lawrence, Stefan Elbel
Two-phase ejectors have received increased attention in recent years because of their ability to improve the performance of automotive air-conditioning cycles by means of expansion work recovery. Much attention in recent years has been given to how high-pressure fluids, such as carbon dioxide, perform with ejector cycles; high-pressure fluids tend to have higher throttling loss, making them more attractive for expansion work recovery cycles, such as the two-phase ejector cycle. However, low-pressure fluids, such as those commonly used in automotive air-conditioning applications, tend to offer significantly lower work recovery potential. Nonetheless, the limited previous work on low-pressure refrigerants in ejector systems has shown that there is some improvement potential when using these fluids with ejector cycles.
2013-04-08
Journal Article
2013-01-1496
Shenghan Jin, Pega Hrnjak
This paper presents experimental results for refrigerant and lubricant mass distribution in a typical automotive A/C (MAC) system. Experiments were conducted by closing valves located at the inlet and outlet of each component after reaching steady state, isolating the refrigerant and lubricant in each component. Refrigerant mass is recovered in a separate vessel using liquid nitrogen to reduce refrigerant vapor pressure to near vacuum. The overall weight is determined within ±1% after the separation of refrigerant and lubricant. The mass of lubricant is determined by using three different techniques: Remove and Weigh, Mix and Sample, and Flushing. The total mass of lubricant in the system is determined with ±2.5% uncertainty on average. R134a and R1234yf are used with PAG 46 oil as working fluid at different Oil Circulation Ratio (OCR), ranging from 2% to 4%. Experiments are conducted in two standard testing conditions: I35 and L35 (SAE Standard J2765).
2013-04-08
Technical Paper
2013-01-1498
Yang Zou, Predrag Hrnjak
Distribution of R134a in four different vertical headers of microchannel heat exchanger was investigated experimentally. R134a was provided into the header by the microchannel tubes (5 or 10 tubes) in the bottom pass. It left the header through the microchannel tubes (5 or 10 tubes) in the top pass representing the upward flow in the heat pump mode of the reversible systems. The inlet quality was varied from 0.2 to 0.8, and the inlet mass flow rate was from 1.5 to 4.5 kg/h per microchannel tube. Among the test conditions, the aluminum and transparent headers show similar results: refrigerant distribution is better when reducing quality at the same mass flow rate and when increasing mass flow rate at the same quality. Increasing the tubes protrusion and the number of the microchannel tubes usually improve the distribution due to the increase in mass flux. Based on the visualization, churn and separated flow regimes are identified.
2013-04-08
Journal Article
2013-01-1493
Gursaran D. Mathur
Experimental tests were conducted on a parallel flow condenser with HFO-1234yf as the working fluid on an AC system bench to determine average and local heat transfer coefficients during condensation of HFO-1234yf for mass flow rates that are typically encountered from idle to highway speeds (800 to 3000 rpms). A condenser from MY 2008 medium-sized sedan was used for this investigation. All original OEM parts were used with the alternate refrigerant. Same TXV set-point was used with HFO-1234yf. The magnitude of the measured heat transfer coefficient for condensation was found to be 8~12% lower in comparison to HFC-134a. The magnitudes of the pressure drop during condensation were of the same magnitude as HFC-134a system. The information from this investigation can be used to in the design of condensers for mobile air conditioning systems with HFO-1234yf as the working fluid.
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