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Viewing 70801 to 70830 of 101928
Technical Paper
1987-02-01
Jeffrey C. Huang, Gary L. Borman
The effects of surface materials and extent of insulation on the heat transfer to the head of an open-chamber diesel were studied. A large instrumentation plug designed to incorporate plates of various materials on the gas-side surface was utilized with a special research head. Instantaneous rates of heat transfer to the plate gas-side surface were measured. Measurement results obtained with a zirconia plate and an insulated metal plate are compared to data for an uninsulated metal plate. The insulation of the metal plate increased its gas-side surface temperature over the uninsulated case by about the same amount achieved with a 6.35-mm-thick zirconia plate. The magnitude of the surface temperature swing for zirconia is not as high as expected from conduction theory, but is substantially higher than that for the uninsulated metal. Significant reductions of steady state heat fluxes were achieved with both the zirconia and the insulated metal compared to the uninsulated metal. However, peak values of surface heat fluxes for the insulated metal were found to be higher than those for the uninsulated metal.
Technical Paper
1987-02-01
Shoichi Furuhama, Yoshiteru Enomoto
A thin film thermocouple with a high accuracy was developed by means of computer analysis, which allowed measurements of instantaneous temperatures and heat fluxes on combustion chamber walls. Conventional Al-alloy and ceramic plates were compared in terms of the heat loss at the upper surface of each piston during combustion, using a gasoline engine and a diesel engine in the series of experiments. It was found by the comparison that the ceramic plates subjected to higher temperatures had greater heat losses in both the gasoline and diesel engines contrary to the anticipation.
Technical Paper
1987-02-01
A. Seeds, P. G. Sheasby
Experiments have been carried out on the collapse behavior, the energy absorption and the flexural stiffness of adhesively bonded, spot-welded and weld-bonded aluminum box structural assemblies and the results compared with those for equivalent spot-welded mild steel structures. It has been found that weld-bonded aluminum box beams can exhibit specific energy absorptions that are three times greater than those for the mild steel beams and, hence, show that aluminum vehicle structures which typically can be built at about half the weight of steel structures, should nevertheless have more than adequate impact resistance. In flexural testing, the results suggest that the overall stiffness improvements of bonded structures may be a combination of improved beam stiffness, and superior connections between structural elements.
Technical Paper
1987-02-01
Tomio Obokata, Naoki Hanada, Toshio Kurabayashi
In order to improve adaptability of the laser Doppler anemometer (LDA) to measurement of gas flow velocities in an internal combustion engine, an optical fiber system composed of a couple of single mode, polarization-preserving optical fibers has been developed to transmit the incident beams. The overall light transmission efficiency of the system is 24 % and not so high, but the system enables real-time measurements of gas flow velocity in the combustion chamber of a small two-cycle engine during firing operation. The velocity data measured are processed with cycle by cycle analysis by stationary time-averaged method to obtain bulk velocity Ū, turbulence intensity u′ and integral time scale of turbulence Lt. The results indicate that Ū varies very much depending on motored and firing operations due to the expansion flow of combustion, accompanying a new flow field formation, and that u′ is about twice and Lt is 40 - 50 % higher during combustion period than the respective values during the same period of motored operation.
Technical Paper
1987-02-01
John W. Daily
A simple spark ignition engine cycle model has been used to illustrate the concept that cycle-to-cycle variations are an inherent consequence of non-linear combustion kinetics. Sample calculations show highly chaotic behavior when the burn time occupies an excessive fraction of the cycle time. The results are consistent with the well known fact the the engine designer must strive to shorten the burn time as much as possible to minimize variations.
Technical Paper
1987-02-01
James C. Keck, John B. Heywood, Georg Noske
Experiments by Gatowski and Heywood have been analyzed to obtain both qualitative and quantitative information on early flame development and burning rates in a square piston premixed spark-ignition engine. Flame growth was observed using high speed Schlieren photography and simultaneous pressure records were obtained using piezo-electric transducers. To study the effects of in-cylinder gas motion several combinations of shrouded and unshrouded inlet valves, and flat and stepped pistons were used. Spark position was also varied. The analysis supports the wrinkled laminar flame model of turbulent flame structure in spark-ignition engines. It also suggests that cycle-by-cycle variations in the growth rate and location of the flame kernel at very early times are the major cause of cycle-by-cycle pressure variations in spark-ignition engines.
Technical Paper
1987-02-01
Gautam T. Kalghatgi
Combustion and pressure development in spark ignition engines are marked by cycle to cycle variations which are especially severe if the mixture is lean. The variations in indicated mean effective pressure (IMEP) that arise from this could be sufficiently severe to cause problems in certain engine operating regimes even in engines which run smoothly at steady operating conditions. Cyclic variations in IMEP could be effectively reduced at source by reducing cyclic variations in combustion. These are known to originate during the initial stage of combustion which can be influenced by the ignition process. Of the various enhanced ignition devices, variants of the spark ignition system seem to be of most practical interest for automobile applications in the immediate future. In the paper, we review the literature on spark ignition, the nature of the spark discharge process and the attempts to improve stability of engine operation through changes in spark ignition.
Technical Paper
1987-02-01
Peter Moorhouse, Michael P. Johnson
Developments in coating processes and evaluation techniques are discussed. Coatings in advanced engines comprise both those for wear resistance and low friction in high temperature advanced diesel engines and those for heat insulation to reduce heat losses or component temperatures. Advanced evaluation techniques used in these developments include hot wear procedures and radiant thermal cycling rigs. Engine testing of advanced components is in progress or is planned.
Technical Paper
1987-02-01
Ingard Kvernes, Rune H. Hoel
A discussion is presented on the various important features which need to be addressed in the design of viable thermal barrier coatings. The most economical way to ensure increased lifetime and operational safety of diesel engine components is to use a coating in order to improve surface properties. By comparing the surface material properties required for engine operations and the properties of coating systems achieved until now, it is evident that the fracture toughness must be improved. The activities include detailed characterization of powders, the coating microstructure and the properties required for engines. A correlation between in-service engine tests and model laboratory experiments will be discussed to the extent that the field test data are available.
Technical Paper
1987-02-01
Karl Anderson
Selection of a coating system for prepainted metal, whether “preprinted” or “prefinished” requires consideration of the conditions under which it will be used. Factors to be considered are: type of substrate to be painted, joining method, forming requirements, service environment, and need for repaintability. Because of the great variety of coating systems available, it is possible to tailor prepainted systems to meet the same requirements as do many postpainted parts. However, it is necessary to insure that the coaters and their coating vendors understand accurately what the systems are required to do. This paper will outline the physical and chemical characteristics of some of the coating systems available from the coil coating industry today, and describe their performance with respect to the factors mentioned above.
Technical Paper
1987-02-01
James H. Bryson
Priming steel before adhesively bonding leads to more reliable, durable joints. This paper demonstrates first the desirability of priming steel before bonding and then the feasibility of using preprinted steel to accomplish this goal. To demonstrate this thesis unpainted, Uniprimed and preprimed steel adherends are compared in appropriate situations. These conditions include surface preparation, exposure to hostile environments, and strain level of the preprimed steel adherend. Since steel often undergoes forming before joining, the effect of strain level on adhesive bonding was evaluated. It was found that neither painted material required surface preparation prior to bonding to obtain good adhesive performance. Both primed adherends showed greater resistance to exposure to hostile environmental conditions, with the preprinted substrate performing better than the Uniprimed substrate. In conclusion, preprimed steel can be adhesively bonded in structural applications.
Technical Paper
1987-02-01
James A. Kieklak
Coated metal products are used by-auto manufacturers to improve productivity and to enhance corrosion resistance. This paper describes the application of organic coatings to coils of metal using state of the art manufacturing equipment and techniques; it also forecasts changes that can be expected. A glossary of terms is provided.
Technical Paper
1987-02-01
Joseph J. Claus
To insure adequate adherence of coatings to metal surfaces, the coil coating industry has historically used abrasive brushes to clean and prepare the substrate. The use of 3-dimensional, nonwoven abrasive brushes to generate a surface finish, remove contamination, and increase the bondability of the coating to the strip is highlighted in this report. The role of chemical cleaners, as well as other abrasive type brushes is also discussed. The continued production of Zincrometal and other precoated materials for use in automotive applications attests to the high performance levels that are achieved by the coil coating process.
Technical Paper
1987-02-01
E. H. James
A literature survey of the laminar burning velocity behaviors of iso-octane-air mixtures has been conducted with a view to recommending a suitable correlation for use in spark ignition engine combustion work. This comprised an initial study of some burning velocity measurement techniques and then considered laminar burning velocity as a function of unburnt gas temperature, dilution, equivalence ratio and pressure. To provide more definitive guidelines, especially with regard to the pressure effect, other hydrocarbon fuel burning velocity data has been reviewed. The recommended correlation utilises the Heimel and Weast (3) atmospheric pressure values with dilution catered for by the Metghalchi and Keck (44) modification. The pressure attenuation was found to vary with equivalence ratio in such a way that the negative pressure exponents increased as mixtures became weaker and richer. This is significant in terms of the trend toward combustion at leaner mixtures. The exponents themselves decrease with unburnt gas temperature increase and this raises the possibility of their becoming positive at high temperature levels.
Technical Paper
1987-02-01
R. M. Traci, F. Y. Su
Multidimensional numerical models of internal combustion engine processes require closure approximations for the effective turbulent reaction rates for the reactive mixture. In the present paper, an engineering level approach, called the “Eddy-Burn-Rate” model, is proposed which attempts to reconcile the multiscale effects of turbulence on flame propagation. Two rate limiting steps are considered: an entrainment or mixing step and a burn or microscale reaction step. The model treats mixing via a two-equation second order closure turbulence model (k,w) and defines a time constant for the fuel oxidation reaction based on laminar flame consumption on the Taylor micro-scale. The Eddy-Burn Rate model is evaluated against alternative turbulent reaction rate closure methods as well as data from two different combustion bombs. Model simulations are compared to combustion bomb data for cylindrical flame evolution in a highly swirling flowfield and in a stagnant but highly turbulent flow. The results indicate that under conditions relevant to IC engine operation the model provides a relatively good representation of the fully developed flame evolution.
Technical Paper
1987-02-01
R. M. Green, C. D. Parker, W. J. Pitz, C. K. Westbrook
The chemical aspects of the autoignition of isobutane are studied experimentally in a spark ignition engine and theoretically using computer simulations with a detailed chemical kinetic mechanism. The results of these studies show that even with the relatively knock-resistant fuel, isobutane, there is still a significant amount of fuel breakdown in the end gas with a resulting heat release and temperature increase. The ability of the detailed kinetic model to predict this low temperature chemical activity is assessed and the model is modified to simulate more closely the experimental observations. We address the basic question of whether this first stage of combustion accounts for a chemical preconditioning of the end gas that leads to the autoignition; or whether it merely provides sufficient heat release in the end gas that high temperature autoignition is initiated.
Technical Paper
1987-02-01
K. E. Stay
Automotive and radiator manufacturing companies are currently using several methods for attaching plastic radiator tanks to metal core assemblies. Recently, an improved plastic tank attachment method was developed. It performs as well or better than other systems and is also less complicated to manufacture. This system, named the “HSK” method, can be used on copper/brass cores as well as aluminum cores. This paper will describe the functional and manufacturing advantages of the “HSK” plastic tank attachment method.
Technical Paper
1987-02-01
Yoichi Ando, ichiro Nita, Matsunobu Uramoto, Hisao Ochiai, Tatsuya Fujiyoshi
The prices of copper and solder are largely influenced by the global situations. On the other hand, bauxite, the raw material required in making aluminum radiators, is inexhaustibly available and its relatively steady supply is obtainable. With such an assumption, research and development of aluminum radiators started in or around 1960. However, we could not develop any new method of processing and aluminum alloy which could compete with copper-made radiators, particularly in corrosion resistance and cost. This resulted in delayment of its practical use. In 1984, we successfully manufactured aluminum radiators owing to NE process in which non-corrosive flux was used. and development of an alloy matching the NB process. This report describes the non-corrosive aluminum. radiator manufactured in the NB process.
Technical Paper
1987-02-01
Edward J. Vydra
Multilayer Composite Materials, discussed in this paper, are defined as laminated structures consisting of two “Skins” of metal separated by a layer of polymeric material, applied as a coating, film or prepreg and adhesively bonded together. Such structures can be successfully manufactured in a continuous manner and this paper describes such composite materials utilized for sound and vibration damping over a wide range of frequencies and temperatures. With high damping properties [loss factor −ƺ (nu) ≥ .05] these materials can be formed and fastened by using existing equipment and technology, (including welding). This presentation is a result of a continuous 5 year effort to develop composite materials. Part of this development involving metal/polypropylene/metal structural composites was presented by H. H. Levine at the 1981 SAE Passenger Car Meeting. [1].
Technical Paper
1987-02-01
Rolf Sundberg, Rolf Holm, Lars Hassel
Demands on longer life time, lower weight, mixing of different materials and last but not least changed corrosion conditions due to pollution and climate conditions have made the corrosion behaviour both externally and internally of automotive heat exchangers more important in recent years. This paper presents our experiences from both field and laboratory tests of copper/brass and aluminium radiators together with some literature results. The main part is dealing with external corrosion. Comments are given on the influence of material properties, production methods and ways of protection. In the case of copper/brass results, from trials and use of an improved corrosion protection with a special type of lacquer are presented. In conclusion, it is stated that the competing materials mentioned, show different characters from a corrosion point of view. These differences are, however, not considered significant enough to be decisive for the choice between copper and aluminium materials for automotive heat exchanger.
Technical Paper
1987-02-01
Phillip L. Coduti
The concept of forming prepainted steel products directly, as an alternative to post-painting formed parts, is economically very attractive. Significant paint burnishing, scoring, and flaking may occur when prepainted steel is subjected to conventional stamping plant forming operations. Results obtained on laboratory friction and forming test equipment show that prepainted steel products coated with solid lubricant films display improved lubricity and formability and exhibit anti-burnishing, -scoring, and -flaking tendencies. These test results successfully predicted field performance of prepainted sheet steel products coated with a solid lubricant: formability was improved and surface damage reduced under actual press line stamping conditions. These improvements have been attributed to a solid lubricious material separating the tool-paint interface.
Technical Paper
1987-02-01
Greg Yates
There is a growing need in the metal industry to produce high-quality, durable products at a lower cost. Because of the strong feeling that preprimed/prelubed metals will meet this need, this paper will examine the role of lubrication in this process change by describing the principles of sheet metal forming, the theory of lubrications, the role of the lubricant, the areas of quality and cost improvement provided by the lubricant, and the effects of such a process change.
Technical Paper
1987-02-01
C. M. Varga, R. J. Brent
With the increased consideration and usage of pre-painted metal in automotive and other manufacturing operations, there is a corresponding increased appreciation (understanding) that lubricants are needed to assure reliability of the process. This assurance relates directly to formability and mar resistance following forming and drawing operations. Evidence has been generated to illustrate the following advantages by use of specially designed lubricants. 1. Improved formability and drawability. 2. Improved paint adhesion through the forming operations. 3. Paint mar resistance. 4. Metal shear characteristics. 5. Anti-blocking properties. 6. Interim raw edge protection. The majority of lubricants proposed for application over paint at the coil coating site are of the dry film type to impart scuff resistance and consistent adhesion integrity of lubricant to paint. Most lubricant films can be easily removed using heated mild alkaline cleaning solutions. Good rinsing is imperative to assure a blemish free surface and promote good topcoat paint adhesion.
Technical Paper
1987-02-01
Ulrich Kemmner, Mathias Rollwage, Klaus Rose
The paper describes a new design of electrical fuel pumps for fuel injection systems. As fuel quality changed considerably in the last years, hot-fuel handling of pumps became insufficient and had to be improved. This was being achieved by connecting a hydro-dynamic pre-stage in series with the main pump unit which is of positive displacement type. Modern cars are highly sophisticated in engine noise reduction. Noise caused by pressure pulsation and body vibration of fuel pumps, having been concealed formerly in the total sound level, is audible now and has to be reduced. Solutions which have been put into practice will be shown and test results obtained on test bench and in cars will be given in this paper.
Technical Paper
1987-02-01
James D. Wells, LeeAnne Dunn, David T. Nicholson
This paper will examine what can be achieved by a diagnostic system using a knowledge based approach as opposed to either hardcoded or “electronic page turner” approaches. We will discuss what can not be achieved with our simple approach, but could be expected from a state-of-the-art expert system. Our development methodology and the current status of DOORKNOB will be reported. Future work and extensions will be outlined.
Technical Paper
1987-02-01
Yoshiyuki Hattori, Hisanori Kobayashi, Kazuo Shinoda
Considerations have been made on using turbine pumps as in-tank fuel pumps for electronic fuel injection systems (EFI). Flow channel dimension values, which had not been previously used for these types of pumps, were found to be very suitable for use as a fuel pump. The oil film visualization method was used to observe the flow pattern within the pump, and the results served to improve the flow channel shape. This contributed to designing a compact and efficient high-pressure fuel pump.
Technical Paper
1987-02-01
Philip C. Jackson
Variable precision logic (VPL) is a formalism for reasoning with uncertain information, in situations where resources constrain the amount of Reasoning which can take place. The conclusions developed using VPL may vary in certainty according to the computational resources that are made available. [2] Thus, VPL appears to have many potential applications, in areas such as diagnosis, classification, real-time control, etc. This paper describes implementation methods for erabedding certain elements of VPL on top of ART, the Automated Reasoning Tool expert systems language developed by Inference Corporation. [3] ART provides a variety of flexible constructs for expert systems programming, so that alternative systems for managing uncertainty can be implemented on top of ART. The elements of VPL discussed in this paper include certainties of facts and rules, censored rules, and time resource constraints on logical derivations.
Technical Paper
1987-02-01
Rajshekhar D. Oza
Integration of design and manufacturing rely on a bidirectional information process of converting knowledge to data and data to knowledge in the frame work of the information hierarchy. This paper describes the first four levels of this hierarchy and argues that approaches from artificial intelligence and data base technology needs to be combined to complete this hierarchy.
Technical Paper
1987-02-01
Ronak Shodhan, J. J. Talavage
Manufacturing system performance is dependent upon its design. Improvement in design can enhance system productivity. Effectiveness of design selection process can be greatly enhanced using a combined simulation-artificial intelligence approach. COMAND, a knowledge-based computer consultant for manufacturing system design, is described.
Technical Paper
1987-02-01
J. C. Lusth, W. R. Schick, G. P. Singh
As expert system technology moves to the factory floor, certain problems naturally arise. Knowledge representation (1)* and acquisition (2) have been stated as major stumbling blocks, which may be true in a general sense. For a specific application, however, representation and acquisition are a minor hurdle compared to the wall of data acquisition and filtering. Expert systems are high-level programs which require high-level concepts to manipulate. Raw data from the factory floor is unsuitable for an expert system and must be filtered and combined into a more appropriate form. In this paper we examine building an expert system for arc welding thin metal plates, and the difficulties in providing the expert system with appropriate high-level concepts.