Mars Exploration Rover Surface Mission Flight Thermal Performance

<div class="htmlview paragraph">Several years ago some of the most prominent leaders in automotive industries cooperated to form a purely engineering group that had as its primary purpose developing a type of rigid-airship construction in which the public would have confidence. It was conceived that such an airship should be</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">(1)</span> <div class="htmlview paragraph">Fireproof</div> </li> <li class="list-item"> <span class="li-label">(2)</span> <div class="htmlview paragraph">Weatherproof</div> </li> <li class="list-item"> <span class="li-label">(3)</span> <div class="htmlview paragraph">Durable and permanent in structure</div> </li> <li class="list-item"> <span class="li-label">(4)</span> <div class="htmlview paragraph">Navigable in practically all kinds of weather</div> </li> <li class="list-item"> <span class="li-label">(5)</span> <div class="htmlview paragraph">Economical in the use of buoyant gas and ballast</div> </li> </ol> </div> <div class="htmlview paragraph">To meet all of these requirements it was decided, after mature consideration, that a substantially all-metal construction was imperative. Development of the Metalclad airship has now reached a point where the general soundness of the design seems fully assured as</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">(1)</span> <div class="htmlview paragraph">The structural and aerodynamic efficiencies have been established by both analytical and experimental methods</div> </li> <li class="list-item"> <span class="li-label">(2)</span> <div class="htmlview paragraph">The technical problems involved in the construction have been mastered to a certainty hitherto unapproached in any new design</div> </li> <li class="list-item"> <span class="li-label">(3)</span> <div class="htmlview paragraph">The general design of an airship of demonstration size, 200,000 cu. ft. or one-tenth the size of the Shenandoah, has been completed</div> </li> <li class="list-item"> <span class="li-label">(4)</span> <div class="htmlview paragraph">Full-sized structural members of every part of the framework have been built and tested to destruction revealing that the minimum safety factor is double that of the Shenandoah. The longitudinal strength of the metal hull will be more than four times as great as that of the Shenandoah</div> </li> <li class="list-item"> <span class="li-label">(5)</span> <div class="htmlview paragraph">The problem of riveting the metal hull-plating has been solved through the perfection of an automatic riveting-machine</div> </li> <li class="list-item"> <span class="li-label">(6)</span> <div class="htmlview paragraph">The problem of making the metal hull gas-tight has been solved with surprising efficiency indicating an osmosis of about one-tenth that through gold-beaters skin and only one-hundredth that through rubberized fabric</div> </li> <li class="list-item"> <span class="li-label">(7)</span> <div class="htmlview paragraph">A suitable coating to prevent corrosion has been satisfactorily tested</div> </li> <li class="list-item"> <span class="li-label">(8)</span> <div class="htmlview paragraph">A source of supply of aluminum alloys of dependable quality is assured</div> </li> <li class="list-item"> <span class="li-label">(9)</span> <div class="htmlview paragraph">Shop facilities for fabrication are available in Detroit</div> </li> <li class="list-item"> <span class="li-label">(10)</span> <div class="htmlview paragraph">Skilled metal-workers familiar with aluminum and its alloys are at hand</div> </li> </ol> </div> <div class="htmlview paragraph">These results depend upon certain fundamental principles that are described in the paper. In effect, the design is an entirely new one, but adheres to the fundamental unalterable principles underlying all sound engineering-work.</div> <div class="htmlview paragraph">The paper states that the Metalclad airship is the last step in the development of rigid airships and most certainly must be adopted if such a means of transportation is to be made available both for the arms of National Defense and for commercial purposes.</div> <div class="htmlview paragraph">Appendices that include extracts from studies and texts arranged to illustrate the subject matter in the main paper and furnish food for discussion supplement the paper. This material is partially elementary in form as limitations of space preclude any attempt at completeness.</div>

<div class="htmlview paragraph">Controlled Auto-Ignition (CAI) combustion, also known as HCCI or PCCI, has recently emerged as a viable alternative combustion process to the conventional spark ignition (SI) or compression ignition (CI) process for internal combustion (IC) engines, owing to its potential for high efficiency and extremely low emissions. One of the most effective and practical means of achieving CAI combustion in an engine is to retain or recycle the burnt gases. In order to understand better the effects of recycled burnt gases on CAI combustion, detailed analytical and experimental studies have been carried out. The analytical studies were performed using an engine simulation model with detailed chemical kinetics.</div> <div class="htmlview paragraph">The five effects of the recycled burned gases studied include:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"><span class="li-label">(1.)</span><div class="htmlview paragraph">Charge heating effect: higher intake charge temperature due to hot burned gases;</div></li> <li class="list-item"><span class="li-label">(2.)</span><div class="htmlview paragraph">Dilution effect: the reduction of oxygen due to the presence of the burned gases;</div></li> <li class="list-item"><span class="li-label">(3.)</span><div class="htmlview paragraph">Heat capacity effect: due to higher specific heat capacity of burned gases;</div></li> <li class="list-item"><span class="li-label">(4.)</span><div class="htmlview paragraph">Chemical effect: chemical reactions involving CO<sub>2</sub> and H<sub>2</sub>O in the burned gases</div></li> <li class="list-item"><span class="li-label">(5.)</span><div class="htmlview paragraph">Stratification effect: recycled burned gases are stratified from the fuel/air mixture.</div></li> </ol> </div> <div class="htmlview paragraph">And the main conclusions are:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"><span class="li-label">(1.)</span><div class="htmlview paragraph">The charge heating effect is mainly responsible for the advanced AI timing due to hot burned gases. It increases the heat release rate and shortens the combustion duration.</div></li> <li class="list-item"><span class="li-label">(2.)</span><div class="htmlview paragraph">The dilution effect does not affect AI timing, but it extends combustion duration. Its slows down the heat release rate only when large amount of burned gases is present.</div></li> <li class="list-item"><span class="li-label">(3.)</span><div class="htmlview paragraph">The heat capacity effect is mainly responsible for the reduction in the heat release rate, and it has a similar effect to extend the combustion duration as the dilution effect.</div></li> <li class="list-item"><span class="li-label">(4.)</span><div class="htmlview paragraph">The chemical effect does not affect AI timing and heat release rate. It reduces the combustion duration slightly at high concentrations of burned gases.</div></li> <li class="list-item"><span class="li-label">(5.)</span><div class="htmlview paragraph">The stratified burned gases facilitate the CAI combustion due to the presence of higher temperature region at the boundary between of the hot burned gases and combustible charge.</div></li> </ol> </div>

<div class="section abstract"><div class="htmlview paragraph">Diesel aftertreatment (AT) systems are critical for controlling emissions of CO, HC, NO<sub>X</sub>, and PM in the on-road transportation sector. Ensuring compliance with regulatory standards throughout the AT system's lifespan requires precise prediction of various degradation mechanisms under real-world operating conditions and mitigating their impact through proper catalyst sizing and advanced controls. In the SwRI A2CAT-II consortium, a medium-duty diesel engine production aftertreatment system was subjected to full useful life aging, involving chemical poisoning with phosphorus (P) and sulfur (S) species, along with hydrothermal aging following the DAAAC protocol. This study was aimed to model and predict the aging trajectory of this production AT system thereby capturing changes in system dynamics under both steady-state and transient conditions. The system, designed to meet the 0.2 g/bhp-hr standard, comprised a Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and Ammonia Slip Catalyst (ASC). It was aged to 3600 hours equivalent to the DAAAC protocol and tested across a series of steady-state and regulatory cycles (HFTP, RMC, and LLC) at degreened, 33%, 66%, and 100% aging points. A linear decrease in system NOx conversion was observed between 0% to 66% aging, followed by a nonlinear drop from 66% to 100%. The cumulative decline in NOx conversion was 0.8%, which could significantly impact systems designed to meet a 0.05 g/bhp-hr target.</div><div class="htmlview paragraph">IntroductionAftertreatment durability demonstration is a mandatory validation exercise for on-road medium and heavy-duty diesel engine certification. This requirement ensures that the emission compliance can be achieved for the intended full useful life (FUL) of the engine system or multiple vehicle families. Conventional Deterioration Factor (DF) approach considers linear effect of sulfur and phosphorous poisoning on the catalysts over the entire useful life based on performance from 33% of aging the catalysts and extrapolating them to FUL. However, based on various studies, the impact of fuel derived Sulfur on diesel aftertreatment components was found to be exponentially significant particularly on the SCR due to the sulfur poisoning effect which require an active means to liberate sulfur to maintain appropriate SCR NOx conversion performance. Phosphorous from lubricating oil is known to adversely affect the activity of the oxidation catalyst in a catalyzed DPF thereby reducing the passive regenerative performance of DPF. For these reasons, an extensive understanding of chemical poisoning (particularly Sulfur and Phosphoros) and hydrothermal aging are warranted to design, validate and demonstrate the durability of aftertreatment components that are subjected to the prolonged chemical exposure.</div><div class="htmlview paragraph">To address the extensive challenges in durability demonstration, the Diesel Aftertreatment Accelerated Aging Protocol, or DAAAC, was developed by Southwest Research Institute as a part of consortium effort that includes input from diesel engine manufacturers [<span class="xref">1</span>, <span class="xref">2</span>, <span class="xref">3</span>]. DAAAC is an accelerated aging cycle developed for each application based on the available field data. It includes the exposure from hydrothermal aging, sulfur and lubricant derived poison at accelerated rates. The protocol also requires the entire aftertreatment system to be aged as a complete system, since the upstream components, such as DOC, can impact the chemical makeup of sulfur derived constituents.</div><div class="htmlview paragraph">The protocol does not introduce chemical constituents not normally observed in the field. The accelerated chemical exposure rate is limited only to a degree that has previously demonstrated successful correlation to normal, unaccelerated aging. The Protocol also requires that chemical aging mechanisms are to be introduced and / or consumed in a manner representative of the engine’s defined consumption pathways. Examples include sulfur exposure via high sulfur fuel or gaseous SO<sub>2</sub> and oil consumption via pre-combustion / post-combustion pathways. The Protocol also does not introduce chemical components that are not normally present in oil or fuel (other than doping the fuel with higher concentrations of sulfur, but this amount is relatively small). A comprehensive step by step breakdown of DAAAC protocol is presented elsewhere [<span class="xref">2</span>].</div><div class="htmlview paragraph">The primary objective of this paper is to disseminate the observation of long-term impacts of chemical poisoning and hydrothermal aging on a production aftertreatment catalyst subjected to FUL DAAAC protocol. The results of this experimental campaign were used to develop and validate a model capable of predicting hydrothermal and chemical aging mechanisms of conventional diesel aftertreatment to optimize long term emissions reduction performance. The paper is divided into following sections: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">Introduction: An overview of the system</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">Background: A review of literature in the field of diesel AT aging</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">Test Campaign: Description of experimental setup used for collection of both steady state and transient data.</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">Experimental setup: Description of burner stand used for data collection.</div></li><li class="list-item"><span class="li-label">5</span><div class="htmlview paragraph">Results and Discussion: Description of experimental results followed by discussion about underlying degradation mechanism identified through simulation work.</div></li><li class="list-item"><span class="li-label">6</span><div class="htmlview paragraph">Summary and conclusion</div></li></ol></div></div>

<div class="htmlview paragraph">A chemical and physical characterization of particulate emitted in undiluted exhaust of single cylinder direct injection (D.I.) diesel engine was made by an optical technique.</div> <div class="htmlview paragraph">On-line scattering and extinction measurements in the spectral range from 200 to 500nm were carried out in the exhaust ofthe engine operating under steady-state conditions. These measurements provided a useful tool for the comprehension of chemical and physical structure of the particulate. They allowed the evaluation in real time of the size, the concentration and also the optical properties. Preliminary results of size and mass concentration of particulate are presented.</div> <div class="htmlview paragraph">A good agreement was observed comparing the results with those obtained by gravimetric measurements, TEM and X-ray diffraction.</div> <div class="htmlview paragraph"><b>HIGH EFFICENCY OF DIESEL ENGINES</b> and their ability to burn heavy fuels make them ofgreat interest in the transportation field. On the other hand, present exhaust emission levels produced by this type ofengine will not satisfy stringent international regulations on environ- menta protection.</div> <div class="htmlview paragraph">The studies of the chemical and physical structure of diesel particulate in the exhaust of the engine help manufacturers both to optimize the efficiency of the combustion process and give useful information to designers of after-treatment devices.</div> <div class="htmlview paragraph">Historically, most studies on the particulate in the engine exhaust were carried out by electron microscopy and chemical analysis [<span class="xref">1</span>,<span class="xref">2</span>]<span class="xref">*</span>. These conventional techniques are time consuming, not real time, and not useful in transient operating conditions. Because the composition of the particulate materia depends on the collection system the data can be influenced by sampling procedures.</div> <div class="htmlview paragraph">Size distribution measurementtechniques of particulate based on electrical mobility, diffusion and inertial separation were proposed by Dolanetal.[<span class="xref">3</span>]. These techniques are real time but intrusive and can change the size distribution through collisions between particles.</div> <div class="htmlview paragraph">The recent advances in non-intrusive optical diagnostic techniques have made it possible to study on-line the evolution of particulate emitted in the exhaust with good temporal and spatial resolution.</div> <div class="htmlview paragraph">In the last decade, the optical measurements carried out in the exhaust, were made by nephetometry, transmissiometryor opacimetry, generally at a single wavelength in the visible range or in the infrared by photoacoustic and absorption measurements, These measurements are used to determine both the mass of particulate and the amount of dry soot and SOF [<span class="xref">4</span>,<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>.]</div> <div class="htmlview paragraph">In particular, simultaneous light scattering and extinction measurements at a single wavelength in the visible have provided a fast method to determine the dimension and concentration of soot particles i n flame [<span class="xref">8</span>].</div> <div class="htmlview paragraph">The purpose of the present study is to demonstrate the feasibility and flexibility of a new optical technique applied in the undiluted exhaustof a D.I. diesel engine. The technique consists of the use of simultaneous spectral measurements of scattering and extinction coefficients from the near ultraviolet to visible. These measurements allow the on-line simultaneous evaluation of the size, concentration and particulate mass as well as estimating the optical properties of the particulate. In particular, optical measurements in the near ultraviolet region are particularly promising because both graphite and large aro- maticmolecules exhibit absorption bands between 200 and 350nm [<span class="xref">9</span>,<span class="xref">10</span>].</div>

<div class="htmlview paragraph">A modified version of KIVA II code was used to perform three-dimensional calculations of combustion in a DI diesel engine. Both an ignition delay submodel and a different formulation of the fuel reaction rate were implemented and tested.</div> <div class="htmlview paragraph">The experiments were carried out on a single cylinder D.I. diesel of 0.75 I displacement equipped with sensors to detect injection characteristics and indicated pressure. A fast acting sampling valve was also installed in the combustion chamber to allow the measurement of main pollutants during the combustion cycle, by an ensemble average technique. Computational and experimental results are compared and the discrepancies are discussed.</div> <div class="htmlview paragraph">Today the demand for light duty engines that produce less emission and consume less fuel is increasing. Thus, if limits on CO<sub>2</sub> emissions are established, the direct injection diesel engine for light duty applications will become an attractive option. Also, manufacturers of heavy duty diesel engines are facing increasingly stringent emission standards. New research efforts aim at improving DI diesels emission behaviour.</div> <div class="htmlview paragraph">Given the complexity of the interaction between the different processes in diesel combustion, comprehensive models of in-cylinder phenomena prove to be useful in providing guidelines for prototype development. Multidimensional analytical models of in cylinder phenomena have been greatly improved over the last decade, given the progress of the efficiency of computer hardware and diagnostic techniques. In particular many authors [<span class="xref">1</span>, <span class="xref">2</span>, <span class="xref">3</span>, <span class="xref">4</span>, <span class="xref">5</span>, <span class="xref">6</span> and <span class="xref">7</span>] have numerically simulated the interaction between the airflow field and the spray and have compared it with experimental data. However, both three dimensional calculations of combustion in the presence of fuel sprays and the corresponding comparisons with experimental data are hardly found in literature. In most cases the comparison between numerical and experimental results is limited to the pressure history and to the fitting of some pollutant emissions late in the expansion stroke.</div> <div class="htmlview paragraph">In particular, limiting the review to diesel combustion, Zellat and others [<span class="xref">8</span>] present calculations of a swirl chamber engine at different loads, injection timings, and speeds, obtained with a modified version of KIVA code. In their results, the computed in-cylinder pressure agrees well with the experimental one. Takeneka and others [<span class="xref">9</span>] used KIVA code to perform calculations of DI Diesel combustion for both swirl chamber and quiescent chamber systems. No details about the modifications introduced in the original code are provided.</div> <div class="htmlview paragraph">Computational comparisons with in cylinder measurements, performed in a quiescent chamber system by Kamimoto [<span class="xref">10</span>], show discrepancies between computations and measurements. Gonzales and others [<span class="xref">11</span>] also used the KIVA II code with the Reitz atomization model and a single step Arrhenius mechanism to describe combustion of tetradecane in a D.I. quiescent chamber engine. The paper focuses on the spray submodel effect on the accuracy of pressure history prediction. It was demonstrated that, if adequate grid resolution is used, prediction of combustion is sensitive to the details of combustion and fuel injection models.</div> <div class="htmlview paragraph">In the present paper a detailed comparison between experiments with a fast acting sampling valve and 3D calculations is presented for a medium duty swirl supported DI engine. Calculations are performed by KI-VA II code with the adoption of the TAB jet break up sub-model and wall impingement modelling. In addition, a different formulation of combustion model is discussed. The current status of the “numerical engine program” in progress at Istituto Motori of CNR, is thus defined.</div>

<div class="htmlview paragraph">Recyclable content of motor vehicles is presently 75%, by weight, the majority of which is iron based components. Approximately 9% of the vehicle weight is in the form of various plastics. Today these materials are shredded and landfilled as automotive shredder residue (ASR). General Motors is putting greater emphasis on recycled automotive component systems through the use of the following environmental principles to guide the design and manufacture of our vehicles:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">General Motors is committed to actions to restore and preserve the environment.</div> </li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">General Motors is committed to reducing waste, conserving resources, and recycling materials at every stage of the product life cycle.</div> </li> <li class="list-item"> <span class="li-label">3.</span> <div class="htmlview paragraph">General Motors is committed to the development and implementation of new materials and process technologies to enable rapid disassembly of component systems at the end of the vehicles' useful life.</div> </li> </ol> </div> <div class="htmlview paragraph">Additional forces driving recycling efforts stem from:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">The reduction in the number of landfills.</div> </li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">Anticipated future legislation aimed at the recycled content of future vehicles.</div> </li> </ol> </div> <div class="htmlview paragraph">This technical presentation contains information and descriptions of recyclable instrument panel systems. Examples of three potentially recyclable instrument panel systems will be discussed. <b>Attention</b> will be given to design flexibility, quality, and costs for automotive components manufactured from processes utilizing these materials.</div>

<div class="section abstract"><div class="htmlview paragraph"><b>Background</b>: The Indian automobile industry, including the auto component industry, is a significant part of the country’s economy and has experienced growth over the years. India is now the world’s 3<sup>rd</sup> largest passenger car market and the world’s second-largest two-wheeler market. Along with the boon, the bane of road accident fatalities is also a reality that needs urgent attention, as per a study titled ‘Estimation of Socio-Economic Loss due to Road Traffic Accidents in India’, the socio-economic loss due to road accidents is estimated to be around 0.55% to 1.35% of India’s GDP [<span class="xref">27</span>] Ministry of road transport and highways (MoRTH) accident data shows that the total number of fatalities on the road are the highest (in number terms) in the world. Though passenger car occupant fatalities have decreased over the years, the fatalities of vulnerable road users are showing an increasing trend. India has committed to reduce road fatalities by 50% by 2030. In this context, the automotive industry as well as MoRTH have been taking multiple initiatives including those related to vehicular and road engineering as well as educational measures for raising awareness in the field of road safety.</div><div class="htmlview paragraph">With the intent of lowering road traffic accidents, the government and the ministry are constantly upgrading the requirements related to vehicles, infrastructures, and their implementation thereof. In this context, various future regulations are being deliberated. One such regulation in discussion pertains to requirements for the protection of the passenger car occupants in the event of a full-frontal collision with a focus on restraint systems (AIS 201). This will push manufacturers to design more sophisticated restraints that would help to reduce restraint-induced injuries. The draft version of the standard is available for public input/ discussion.</div><div class="htmlview paragraph">The key objective of the study documented herein is to consider various aspects of the draft standard (AIS 201) from the Indian perspective. This study investigates the research questions, enumerated below: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">What should be the appropriate test speed for the full-frontal test based on Indian accident data?</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">What is the suitable dummy configuration in terms of gender, seating position, and age to maximize occupant safety in full frontal accidents?</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">Is the proposed ATD’s anthropometry (weight and height) suitable, based on the people involved in full frontal cases in India?</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">What are occupant injury attributes in full-frontal accidents?</div></li></ol></div><div class="htmlview paragraph"><b>Key findings/ expected research findings</b>: India has a very different mix of road traffic users and road traffic fatalities compared to that in Europe (Refer to <span class="xref">Table 1</span>). Further, issues like seat belt usage are of utmost concern. The demographic for India is also very different from those of developed economies. With India being a country with a rather young population, male and female dummies for driver and front passenger positions should be looked upon. This calls for India-specific safety regulations and research work on automotive test dummies.</div><div class="htmlview paragraph"><b>Practical implications</b>: The study can potentially provide a suggestion for alignment of the regulatory requirements with the actual situations, thereby increasing the effectiveness of the standard.</div></div>

<div class="htmlview paragraph">This is an analysis of spring action such as occurs on an automobile driven on a highway having bumps and depressions, a discussion of the requirements of spring-recoil checking devices, and an account of experiments made with a car on which different combinations of springs of various lengths and flexibilities were used and the distribution of weight on the frame was varied. Spring action was analyzed previously by means of small models that simulated the suspension and weight distribution of a motor-car. The compression and recoil action of springs and their relation to the travel of the car as represented by the time element are discussed. Although the more-flexible springs absorb the bumps better, it is shown that their recoil is greater unless it is damped by a shock-absorbing device.</div> <div class="htmlview paragraph">The limitations of shock-absorber or recoil-check design are pointed out and the author asserts that a device that never allows the springs to reach their normal position stiffens the springs and increases the riding-discomfort. Obviously, the more the springs are tied-down the stiffer they become and the less capable of depression when striking a bump. That interleaf friction can be a satisfactory means of taking-up spring recoil is an erroneous belief that must be discarded, is asserted, and the greatest improvement in riding-comfort that can be made in the average car by the owner at reasonable expense is to grease the springs well, put on spring covers and automatic lubricators, and fit shock-absorbers that resist the spring recoil but do not make the springs stiffer on the bumps.</div> <div class="htmlview paragraph">To check conclusions arrived at from analysis and casual observations, experiments were made with a car on the road. These are illustrated and described. As a result of the study and the limited number of road experiments made up to the time of writing, the author concludes that</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">(1)</span> <div class="htmlview paragraph">Front springs must be shackled at the front end or so mounted that full spring-travel can occur without changing the direction of the front wheels; heavier master leaves may be required for safety, and one or two rather heavy leaves above them will make the axle stable under application of four-wheel brakes</div> </li> <li class="list-item"> <span class="li-label">(2)</span> <div class="htmlview paragraph">Longer front springs must be used and room for spring action must be increased to at least 4 in.</div> </li> <li class="list-item"> <span class="li-label">(3)</span> <div class="htmlview paragraph">Internal friction of the springs must not exceed 10 per cent of the normal weight they support, and if leaf springs are used they must be lubricated</div> </li> <li class="list-item"> <span class="li-label">(4)</span> <div class="htmlview paragraph">Efficient devices that will check the spring recoil at the proper time and not restrict the yield of the springs on bumps or when the wheels drop into road depressions must be fitted</div> </li> <li class="list-item"> <span class="li-label">(5)</span> <div class="htmlview paragraph">The procedure in developing the spring-suspension of a car should be changed; the tests with new models prior to production should be made with springs of various lengths and flexibilities and with various distributions of weight on the frame. With different body-models it may be necessary to use springs of different characteristics</div> </li> <li class="list-item"> <span class="li-label">(6)</span> <div class="htmlview paragraph">Every effort should be made, under present limitations of passenger-car design, to locate the weight over the axles rather than between them</div> </li> </ol> </div>

<div class="htmlview paragraph">Regulated and non-regulated emissions from five current European diesel passenger cars and one light-duty diesel truck were measured to assess the environmental impact of diesel vehicles and to help determine the emission characteristics of the two types of combustion systems: indirect injection (IDI) and high speed direct injection (HSDI). The vehicle emissions were measured using the European Motor Vehicle Emissions Group (MVEG) cycle and the U.S. Federal (FTP 75) test procedures. Measured emissions included HC, CO, NO<sub>x</sub> and particulate mass (PM), C<sub>1</sub> to C<sub>12</sub> hydrocarbon species (here called light hydrocarbon or LHC), aldehydes, particulate composition and particle size distribution. The particulate composition measurements included soluble organic fraction (SOF), its oil and fuel sub-fractions, and the sulfate fraction. All passenger cars and the light-duty commercial vehicle tested complied with the current European Emissions Directive 91/441/EEC. Two passenger cars achieved the EEC Stage 2 levels, and one nearly met the 1994 Tier I U.S. Federal standards. The LHC accounted for between 35 to 78% of the total HC measured by the heated FID analyzer. Fuel and oil comprised between 12 and 30% of the PM emissions. The non-methane organic gases (NMOG) emissions and the LHC ozone reactivity from diesel cars were both about 50% less than those from gasoline cars. Of the non-regulated emissions, formaldehyde was generally below 0.009 g/km, and benzene emissions were below 0.0035 mg/km. The results were compared with European gasoline vehicles and the Current Gasoline Vehicle fleet of the U.S. Air Quality Improvement Program (AQIRP), and an assessment was made of the relative environmental impacts of gasoline and diesel vehicles.</div> <div class="htmlview paragraph">Over the last 20 years, there has been a substantial effort to lower the exhaust emissions from both diesel and gasoline passenger vehicles. Over the same period, the percentage of diesel passenger vehicles purchased in Europe has been increasing steadily(<span class="xref">1</span>)<span class="xref">*</span>. Lower operating(<span class="xref">2</span>) and maintenance costs, and better durability with equivalent drive performance appear mainly responsible for the increased diesel sales. However, even though both diesel and gasoline vehicles meet the current emission standards, questions have arisen about their relative impact on the environment(<span class="xref">3</span>). In addition, with future requirements for lower emissions, these questions will undoubtedly continue.</div> <div class="htmlview paragraph">The relative environmental impact of diesel and gasoline vehicles is still uncertain because there are relatively few published data on the emissions of current diesel vehicles and because the environmental impacts of the expected emissions are not clearly understood. Data on the regulated emissions for diesel passenger vehicles sold in Europe are available from the German Government:(<span class="xref">4</span>) starting in 1991. There are also published reports on regulated emissions from late 1980 and early 1990 diesel cars in the literature(<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>). Still there are few reports on the non-regulated emissions from current diesel vehicles(<span class="xref">8</span>,<span class="xref">9</span>,<span class="xref">10</span>).</div> <div class="htmlview paragraph">On the other hand, there are substantial published data on the regulated emissions of current gasoline vehicles(<span class="xref">11</span>). In addition, there are substantial data on the non-regulated emissions of gasoline cars, especially from the U.S. Air Quality Improvement Research Program (AQIRP)(<span class="xref">12</span>). The AQIRP emissions data included measurements of over 150 individual hydrocarbon and aldehydic compounds which allow estimates of the amount of urban ozone formed from the exhaust and of the atmospheric toxic compound levels. Diesel vehicles were not included in AQIRP.</div> <div class="htmlview paragraph">This paper reports on detail regulated and non-regulated emissions measurements for six 1992/93 model year diesel vehicles, including two Ford and four competitor vehicles. The emissions were measured on both the 1993 European MVEG cycle and the U. S. Federal test procedure. The U. S. AQIRP analytical methods were used for hydrocarbon and aldehydic speciation. The report discusses the regulated emissions from the six diesel vehicles compared to emissions standards, their contribution to urban ozone formation, toxic levels and global warming. It also compares the exhaust emissions of current diesel and gasoline vehicles to help clarify their relative environmental impact.</div>

<div class="section abstract"><div class="htmlview paragraph">Selecting the right EMI/EMC filter is a major challenge when system noise levels exceed compliance or pre-compliance limits. Inline PCB filters are designed to mitigate noise in standalone conditions, but their behavior changes when integrated into a larger system due to unknown parasitic’s. These parasitic’s can disrupt electromagnetic compatibility (EMC), leading to non-compliance [<span class="xref">1</span>, <span class="xref">2</span>]. To address this, engineers often use off-the-shelf EMI filters, but determining their real-world effectiveness remains complex. Even with simulation-based methods, accurately predicting insertion loss and attenuation is difficult due to limitations in conventional modeling approaches [<span class="xref">4</span>, <span class="xref">5</span>].</div><div class="htmlview paragraph">Traditional SPICE-based simulations rely on static models defined at specific frequency points, with interpolated values for intermediate frequencies. This interpolation introduces inaccuracies, affecting the precision of simulated results [<span class="xref">6</span>, <span class="xref">8</span>]. To overcome these limitations, we propose a methodology that reconstructs a realistic EMI/EMC filter model based on insertion loss characteristics under symmetrical and unsymmetrical conditions.</div><div class="htmlview paragraph">Our approach involves deconstructing the EMI/EMC filter into its subcomponents—X-capacitance, Y-capacitance, common mode choke CMC, busbar, and PCB traces—and parameterizing them using CST simulations [<span class="xref">6</span>, <span class="xref">8</span>]. Instead of relying on physical measurements, which are prone to parasitic influences, we extract subcomponent values from datasheets. We focus on dominant parasitic elements exceeding 1 pF and 1 nH, as lower values predominantly affect GHz-range frequencies rather than the MHz-range compliance limits [<span class="xref">4</span>, <span class="xref">5</span>], analyzing impact of parasitic’s on insertion loss, resonance, and damping characteristics, a filter model that represents real-world behavior with a certain error percentage [<span class="xref">2</span>, <span class="xref">4</span>, <span class="xref">5</span>].</div><div class="htmlview paragraph">This methodology results in a high-fidelity EMI/EMC filter model with minimal deviation from actual performance. It enables precise pre-compliance conducted emissions simulations and facilitates optimized filter selection and tuning based on system-specific noise conditions.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Developing the most advanced wing panel assembly line for very high production rates required an innovative and integrated solution, relying on the latest technologies in the industry.</div><div class="htmlview paragraph">Looking back at over five decades of commercial aircraft assembly, a clear and singular vision of a fully integrated solution was defined for the new panel production line. The execution was to be focused on co-developing the automation, tooling, material handling and facilities while limiting the number of parties involved. Using the latest technologies in all these areas also required a development plan, which included pre-qualification at all stages of the system development.</div><div class="htmlview paragraph">Planning this large scale project included goals not only for the final solution but for the development and implementation stages as well.</div><div class="htmlview paragraph">The results: <ul class="list disc"><li class="list-item"><div class="htmlview paragraph">Design/build philosophy reduced project time and the number of teams involved. This allowed for easier communication and extended development time well into the project.</div></li><li class="list-item"><div class="htmlview paragraph">All design teams (machine, tooling, automation, controls) collocated and worked together on integration during all stages of development and implementation for the highest level of integration.</div></li><li class="list-item"><div class="htmlview paragraph">Innovative integration of the tooling and the automated equipment evolved throughout project with the teams working as one group.</div></li><li class="list-item"><div class="htmlview paragraph">Latest fastening technology using all electric, ball-screw squeeze riveting was developed for high-speed and robust automated fastening.</div></li><li class="list-item"><div class="htmlview paragraph">Latest mobilization technology was used to make the automated fastening machines interchangeable to reduce MTTR and to enable more PPM activities offline without affecting production.</div></li><li class="list-item"><div class="htmlview paragraph">More automation was also introduced for tool changing and to the material handling systems for more consistent processing and to reduce operator intervention.</div></li><li class="list-item"><div class="htmlview paragraph">All systems were developed together for full integration and to enable more safety interlocks and HMI for simplified operation.</div></li><li class="list-item"><div class="htmlview paragraph">A 30 month schedule for the complete large scale assembly line was maintained to support the new aircraft launch schedule.</div></li></ul></div><div class="htmlview paragraph">The final solution was a coherent, streamlined and efficient assembly line capable of very high aircraft production rates (<span class="xref">Figure 1</span>).</div><div class="htmlview paragraph"><figure id="F1" class="figure"><div class="graphic-wrapper"><img class="article-figure figure" src="2015-01-2492_fig0001.jpg" alt="PAL, automation cell, Line 4, Position 1 (L4P1)"/></div><span class="label">Figure 1</span><figcaption class="caption"><span class="title">PAL, automation cell, Line 4, Position 1 (L4P1)</span></figcaption></figure></div></div>

<div class="section abstract"> <div class="htmlview paragraph">This specification defines test methods and performance criteria for evaluating ultrasonically welded wire-to-terminal metallurgical bonds. The examples used are specific to the linear weld type of process equipment. USCAR-38 is not applicable for “Splice Welding”. The specification is applicable to wire-on-pad configurations with a typical weld shown in <span class="xref">Figure 1</span>. This test specification subjects parts under test to environmental exposures to simulate a lifetime of field exposure for a road vehicle. Exposures called-out in this specification include Thermal Shock, Temperature Humidity Cycling and mechanical abuse. This test specification is intended to evaluate the strength and performance of the interface between wires to an electrical terminal. Validation of the performance of the Terminal is a separate task and can be accomplished using a component validation test such as SAE/USCAR-2, which evaluates whether the entire connection system is acceptable.</div> <div class="htmlview paragraph">If the weld under test (WUT) is different than described in this section, or is subjected to conditions beyond what is typical of automotive use, the SAE/USCAR-38 test sequence may not be applicable. Parts used in custom applications must pass tests simulating the actual conditions encountered before they can be considered acceptable for that application.</div> <div class="htmlview paragraph">Vehicle and product conditions applicable to use of this specification are:</div> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1)</span> <div class="htmlview paragraph">Applicable use: This specification is applicable where the wire and terminal are part of an electrical connection system used in road vehicles at ambient temperatures from -40°C to +150°C. Applied voltage may be either low (0 - 60 VDC) or high (to 600V). USCAR-38 applies to all wire lengths and includes a special test for wires shorter than 500mm where a weld is done after another component has been assembled to the wire (test samples must be made from the exact production-intent welding process to assess potential process damage risk to the terminal at the other end of the wire. Wire harness makers typically will be given the responsibility to track short wire applications per a statement in the applicable engineering statement of work.</div></li> <li class="list-item"> <span class="li-label">2)</span> <div class="htmlview paragraph">Applicable designs: The procedures described are applicable to buss, terminal, or device connections, including eyelet and battery terminations comprising either single or multiple wire terminations. Designs withd without crimped insulation wings are applicable.</div></li> <li class="list-item"> <span class="li-label">3)</span> <div class="htmlview paragraph">Applicable wire: This specification was developed using clean, bare, uncoated, stranded automotive wire. Wire with tin coatings, applied lubricants, or contamination is known to affect the mechanical and electrical performance of ultrasonically welded cable terminations and are not applicable to be evaluated per this spec.</div></li> <li class="list-item"> <span class="li-label">4)</span> <div class="htmlview paragraph">Applicable wire sizes: Copper wire sizes between 0.22mm<sup>2</sup> to 85mm<sup>2</sup> per ISO 6722-1 wire specification and aluminum (per ISO 6722-2) sizes from 0.5mm<sup>2</sup> to 120mm<sup>2</sup> are applicable. Other wire types may be tested per this specification but cannot claim compliance to this specification since those sizes are out of our experience. Examples of representative “other” wires types are: compressed core, compacted core, solid wire core, and wire core materials other than copper, copper alloy, aluminum, or aluminum alloy. Examples of different center core materials are copper-clad or steel-center-core wires.</div></li> <li class="list-item"> <span class="li-label">5)</span> <div class="htmlview paragraph">The validation process described applies only to linear ultrasonic welding, typically with pressure, energy, and amplitude set as inputs and weld time controlled by limiting energy based on ‘feedback’ from process monitoring sensors. Using process feedback assures the energy-per-weld is maintained. If the equipment used to make samples for USCAR-38 testing is different from this description, this spec may need to be modified or may not be applicable.</div></li></ol> </div>

<div class="section abstract"> <div class="htmlview paragraph">The figures in this SAE Information Report illustrate the principle that, regardless of composition, steels of the same cross-sectional hardness produced by tempering after through hardening will have approximately the same longitudinal<span class="xref"><sup>1</sup></span> tensile strength at room temperature.</div> <div class="htmlview paragraph"><span class="xref">Figure 1</span> shows the relation between hardness and longitudinal tensile strength of 0.30 to 0.50% carbon steels in the fully hardened and tempered, as rolled, normalized, and annealed conditions. <span class="xref">Figure 2</span> showing the relation between longitudinal tensile strength and yield strength, and <span class="xref">Figure 3</span> illustrating longitudinal tensile strength versus reduction of area, are typical of steels in the quenched and tempered condition. <span class="xref">Figure 3</span> shows the direct relationship between ductility and hardness and illustrates the fact that the reduction of area decreases as hardness increases, and that, for a given hardness, the reduction of area is generally higher for alloy steels than for plain carbon steels.</div> <div class="htmlview paragraph">It is evident from these curves that steels of the same cross-sectional hardness have about the same strength characteristics, so that any one of several different compositions would yield the same results. For some specific application then, the first thing to be determined is what composition is required to obtain proper hardening in the size section involved. This information is not contained in mechanical property charts, but can be determined from published data or by means of a hardenability test. Methods of making this hardenability test and interpretation of the test results are provided in SAE J406b.</div> <div class="htmlview paragraph">Having selected a steel that will through harden in the size section under consideration, the engineer must decide from the service stresses imposed on the finished part what tensile properties are required in the part. These tensile properties may then be converted to hardness values from the figures given here; and from <span class="xref">Figure 4</span> showing the effect of tempering temperature on hardness, the appropriate tempering temperature to obtain this hardness can be selected. In <span class="xref">Figure 4</span> the curves are approximate values to be used as a guide. Carbon steels and lean alloy steels, when fully hardened, will fall slightly below the curves and strongly alloyed steels will fall slightly above the curves.</div> <div class="htmlview paragraph"><span class="xref">Figure 4</span> showing the effect of tempering temperature on hardness is a summary of information contained in a large number of mechanical property charts published by steel companies, alloy suppliers, and users. These charts represent, as do the charts on tensile, yield strengths, and reduction of area, data on all SAE alloy and carbon steels with carbon contents of 0.30 to 0.50%.</div> <div class="htmlview paragraph">Mechanical property values obtained from these few summary figures will be as accurate as the information formerly available in a large number of charts, each representing an individual type of steel. For more exact information it would be necessary to make tests on samples from individual heats of steel.</div> </div>

<span class="label">I</span> <div class="htmlview paragraph">The increasing infiltration of technology into our society has resulted in a growing need for a technology-literate public who understands and supports areas of advancement. In addition, there is a current lack of technically skilled workers to fill the present job market in the United States due to the lack of students who are adequately prepared or interested in fields such as science, mathematics, engineering and technology (SMET). The K-12 students who are currently in our school districts are the policy makers, technical workers, and educators of tomorrow. In order to increase the number of Americans who are both technically literate and capable of performing the needed technical jobs, emphasis must be placed on improving the educational system in grades K-12 where the process of learning science and mathematics first begins. The focus on improving the educational system must begin with the teachers because they have the greatest impact on the knowledge that students obtain and on their attitudes toward the subjects.</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1)</span> <div class="htmlview paragraph">Teachers need to be hired and retained who possess strong backgrounds in science, mathematics, engineering, and technology.</div> </li> <li class="list-item"> <span class="li-label">2)</span> <div class="htmlview paragraph">Teachers need to be given accountability and support through mentoring programs to provide them with the help they need to become established in the teaching profession.</div> </li> <li class="list-item"> <span class="li-label">3)</span> <div class="htmlview paragraph">Professional development is needed to keep their skills current and to train them in the most effective methods of presenting the information to their students.</div> </li> <li class="list-item"> <span class="li-label">4)</span> <div class="htmlview paragraph">In order to retain quality SMET teachers, they need to be treated as professionals, given respect, and rewarded for their accomplishments.</div> </li> <li class="list-item"> <span class="li-label">5)</span> <div class="htmlview paragraph">Finally, the teachers need to incorporate technology into their classrooms and utilize other resources, such as engineering societies, to bring real-world experience to the classroom.</div> </li> </ol> </div> <div class="htmlview paragraph">Only when the teachers are well prepared, confident in their subject area, continually updating their skills, receiving recognition, and utilizing important resources will the students receive the education necessary to make them future leaders in science, math, engineering, and technology.</div>

<div class="section abstract"> <div class="htmlview paragraph">This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use.</div> <div class="htmlview paragraph">The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems.</div> <div class="htmlview paragraph">The specific purpose of this document is to define a µPVT Test for the evaluation of the variation of wet friction system performance as a function of speed, temperature, and pressure. This procedure is intended as a standard for both suppliers and end users.</div> <div class="htmlview paragraph">The only variables selected by the supplier or user of the friction system are:</div> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">a</span> <div class="htmlview paragraph">Friction material</div></li> <li class="list-item"> <span class="li-label">b</span> <div class="htmlview paragraph">Fluid</div></li> <li class="list-item"> <span class="li-label">c</span> <div class="htmlview paragraph">Reaction plates</div></li></ol> <div class="htmlview paragraph">These three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document.</div> <div class="htmlview paragraph">This procedure is intended to evaluate the midpoint, endpoint, and breakaway coefficients and endpoint/midpoint ratios. The procedure can be used to demonstrate changes that occur between the different levels of engagement speed, sump temperature, and apply pressure. Refer to SAE J2487, SAE J2488, or SAE J2489 for coefficient variations due to changes in power level.</div> <div class="htmlview paragraph">The procedure, as described in detail in <span class="xref">Table 1</span>, consists of four 50 cycle break-in levels at 3500 rpm with increasing steps of apply pressure, followed by 16 levels consisting of 25 dynamic engagements, and one breakaway following completion of the 25th dynamic cycle. The 16 levels are achieved by varying initial engagement speed, apply pressure, and oil sump temperature while the inertia is kept constant at 0.701 kg/m<sup>2</sup>.</div></div>