Particulate Measurement by Simultaneous Polychromatic Scattering and Extinction Coefficients

<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="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 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">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">All internal combustion piston engines emit solid nanoparticles. Some are soot particles resulting from incomplete combustion of fuels, or lube oil. Some particles are metal compounds, most probably metal oxides. A major source of metal compound particles is engine abrasion. The lube oil transports these abraded particles into the combustion zone. There they are partially vaporized and ultrafine oxide particles formed through nucleation [<span class="xref">1</span>]. Other sources are the metallic additives to the lube oil, metallic additives in the fuel, and debris from the catalytic coatings in the exhaust-gas emission control devices. The formation process results in extremely fine particles, typically smaller than 50 nm. Thus they intrude through the alveolar membranes directly into the human organism. The consequent health risk necessitates a careful investigation of these emissions and effective curtailment.</div><div class="htmlview paragraph">Substantial information is available on diesel engine particulate emissions [<span class="xref">2</span>, <span class="xref">3</span>, <span class="xref">4</span>] but less for SI engines. Beside an example of metal oxide particles from a diesel engine, the present paper shows preliminary results of nanoparticles emissions of SI engines.</div><div class="htmlview paragraph">Four SI engines were investigated: two older and two newer engines, comprising two car engines and two motorbikes. The tests were done on standard transient driving cycles, and steady-state at constant 50 km/h and idling. Prior investigations observed, especially during idling, high concentrations of metal oxide particles [<span class="xref">2</span>]. All tests were done with particle samples collected from the CVS tunnel, during a long operating period, to have sufficient material for analyzing the composition. At the steady-state points, the particle size spectra were measured.</div><div class="htmlview paragraph">The results show that the older SI engines emit high concentrations of soot particles and metal oxide (= ash) particles. The size distribution is decisively bimodal for both soot and ash particles.</div><div class="htmlview paragraph">The newer engines' emission results are less uniform and the concentrations lower, as expected. Altogether, the concentrations of these metal oxide particles are so high, that more detailed investigations are recommended.</div></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="htmlview paragraph">The specific aim is to validate an engineering model for direct injection (DI) Diesel engine emissions. Characteristic times describing the controlling fluid mechanics and chemical kinetics will be employed in the model to correlate both NOx and particulate emissions. Because the model equations are algebraic, they are suitable for implementation in a phenomenological cycle simulation program, or as an emissions model option in a computational fluid dynamics code.</div> <div class="htmlview paragraph">An original premise was that earlier work on global NO chemistry based on pollutant emissions dominated by diffusion flame contributions had adequately elucidated the kinetic aspects of the model. It is shown here that this approach is not valid for modern engines. Rather, an improved two-zone flame model for NO formation/decomposition is required. Mellor et al. [<span class="xref">1</span>] propose such a model, but include only qualitative preliminary model validation. Here we further test the model using measurements from a high speed direct injection (HSDI) Diesel engine with a common rail fuel injection system. Exhaust gas recirculation variations from zero to maximum level possible are reported and correlated for parametric variations of engine speed, injection pressure, and load.</div> <div class="htmlview paragraph">The two-zone NOx HSDI Diesel characteristic time model (CTM) involves a skeletal mechanism consisting of seven elementary reactions [<span class="xref">1</span>]. A surrogate stoichiometric flame temperature around a spray plume at start of combustion conditions represents the environment for NO-forming eddies in the first zone. The second zone surrounds the stoichiometric region, and NO decomposition may occur depending on a surrogate flame temperature at the end of combustion computed from fuel/air dual (i.e., limited-pressure) cycle analysis. Both Zeldovich and nitrous oxide mechanisms are considered in each zone.</div> <div class="htmlview paragraph">Two objectives are accomplished in the present paper. First, in Mellor et al. [<span class="xref">1</span>] the N<sub>2</sub>O mechanism was postulated to be important to the NO formation kinetics under Diesel engine in-cylinder conditions. In addition, it was suggested that NO decomposition reactions may occur at high engine loads through the reverse N<sub>2</sub>O and Zeldovich mechanisms. These hypotheses are validated using the measured engine data. Second, we extend the previous work through preliminary development of the fluid mechanic aspects of the model. A characteristic mixing time that is a function of Reynolds number, Weber number, and engine geometry is developed. When used in combination with the kinetic time for NO formation as a Damköhler number, correlations of NOx emissions for the above parametric variations are obtained for conditions where NO decomposition does not occur.</div>

<div class="section abstract"><div class="htmlview paragraph">Increasing concerns due to global warming have led to stringent regulation of greenhouse gas (GHG) emissions from diesel engines. Specifically, for GHG phase-2 regulation (2027), more than 4% improvement is needed when compared to phase-1 regulation (2017) in the light heavy-duty (LHD) diesel engine category. At the same time, California Air Resources Board (CARB) and Environmental Protection Agency (EPA) have proposed the new Low NOx standards that require up to 90% reduction in tailpipe (TP) NOx emissions in comparison to the current TP NOx standards that were implemented in 2010. In addition, CARB and EPA have proposed new certification requirements – Low Load Cycle (LLC) and revised heavy-duty in-use testing (HDIUT) based on the moving average window (MAW) method that would require rigorous thermal management. Hence, strategies for simultaneous reduction in GHG and TP NOx emissions are required to meet future regulations.</div><div class="htmlview paragraph">This paper presents potential pathways to achieve the GHG phase-2 and the ultra-low NOx (ULN) regulations with minimum changes in engine design, while meeting the constraints that need to be considered for engine performance stability, component durability, and vehicle drivability. Experimental evaluations were performed focusing on transient cycles such as heavy-duty Federal Test Procedure (hereafter referred as FTP), LLC, and custom transient cycles for HDIUT assessment. We used a model-year (MY) 2021 production Isuzu diesel engine and an advanced dual-dosing aftertreatment system comprising of a close-coupled SCR (ccSCR), diesel oxidation catalyst (DOC), diesel particulate filter (DPF), selective catalytic reduction (SCR), and Ammonia Slip Catalyst (ASC). Conventional thermal management techniques such as multi-injection, intake, and exhaust throttling were implemented to achieve the emissions targets. In addition to the proposed system design, this paper presents following test results from a full-scale system evaluation: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">Achieve rapid and sustained turbine-out exhaust temperatures (>200°C) while meeting the engine-out emissions constraints for soot and total hydrocarbon (THC) emissions.</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">A summary of TP NOx, TP N2O and GHG emissions over a composite FTP and LLC.</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">HDIUT assessment results and observations for LLC and custom transient cycles.</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">Robustness evaluation of TP NOx emissions for composite HDT, LLC and custom transient cycles by imposing component variations.</div></li></ol></div></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="htmlview paragraph">The production unit number of small diesel engine cars tends to decline except recreational vehicles in Japanese market in recent years, while the production unit number in Europe market keeps on increasing owing to the merits of the durability and the fuel consumption. The small diesel engines will have to be improved in the near future by solving major problems such as noise and vibration pollution, environmental pollution, improvement in performance of diesel engines, in order to expand the production of the engines.</div> <div class="htmlview paragraph">This paper refers to a basic study on the experimental and analytical methods for the reduction of resonant vibration in each vibration mode on some cylinder blocks of small high-speed diesel engines in rated engine speed range. Hammering test method, which is easy and useful for measuring frequency response functions, is carried out in the experiments. In this test, the cylinder blocks are directly excited with the impulse hammer, and more the main journals are excited via the newly-made force transmission parts in the next experiment. Two kinds of the engines which have been recently recognized as low noise and vibration engines are chosen in this study. The cylinder blocks of the engines are called of long skirt type and ladder frame type, respectively. The vibration characteristics of these cylinder blocks are obtained in the frequency range from 500 <i>Hz</i> to 2 <i>kHz</i> using the experimental modal analysis. This frequency range is chosen in consideration of the reliability of the vibration experiments. And the force transmission routes from the piston heads to the crank journals of each cylinder block are considered as mentioned in the latter experimental method. The experimental results are used to calculate the natural frequencies by the modal analysis and the calculated results are compared with the ones obtained from FEM analysis. Furthermore, the cylinder blocks are remodeled in order to reduce the vibrations of all modes using FEM analysis.</div> <div class="htmlview paragraph">Consequently, it has been shown that the vibration stress of the cylinder block can be reduced by higher rigidities and more lightening weights of the crankcase and the crank journals in the measured frequency range.</div> <div class="htmlview paragraph">The conclusions are described as follows;</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1</span> <div class="htmlview paragraph">The hammering test method using the force transmission parts is useful to measure the natural frequencies of a cylinder block. This method can be easy to get the equal results with the measured ones on running conditions without engine operation.</div> </li> <li class="list-item"> <span class="li-label">2</span> <div class="htmlview paragraph">The hammering test method using the force transmission parts can easily analyze the natural frequencies at all the vibration modes on equal conditions with running ones. Then the method is a useful tool for improving the vibration characteristics.</div> </li> <li class="list-item"> <span class="li-label">3</span> <div class="htmlview paragraph">It has been proved from the analytical viewpoints that the cylinder block of the ladder frame type can be adopted as low-noise, small diesel engines with little increase of the engine weight while maintaining higher rigidity.</div> </li> </ol> </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="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">1</span> <div class="htmlview paragraph">Small scooters are very much used in the congested centers of the European cities. Even if there is a continuous technical progress, the small two-wheelers are a remarkable source of air pollution.</div> <div class="htmlview paragraph">During the research programs of the Swiss Federal Office of Environment Forests and Landscape (FOEFL) - and as a contribution to the European project ARTEMIS <span class="xref">*</span><sup>)</sup> analysis of limited and nonlimited emissions of scooters was performed.</div> <div class="htmlview paragraph">Exhaust emissions measurements of two Scooters: 4-stroke 125 cc and 2-stroke 50 cc have been performed with and without catalyst.</div> <div class="htmlview paragraph">Identical driving cycles have been repeated and the influence of the cooling duration on limited the emissions at cold start was investigated.</div> <div class="htmlview paragraph">A cold start in the temperature range of 20 - 25 °C can be regarded as a “summer cold start”.</div> <div class="htmlview paragraph">As nonlimited emissions the nanoparticulate emissions at cold and warm operating conditions were measured by means of SMPS, ELPI and NanoMet <span class="xref">*</span><sup>)</sup>. The measurements were both: at steady state and at transient operating conditions.</div> <div class="htmlview paragraph">The present work cleared up several details about the emissions of small scooters and confirmed the necessity of further activities to reduce these emissions. This would be an important contribution to improve the air quality in the cities.</div>

<div class="htmlview paragraph">Cast aluminum alloys 356 and 319 and wrought alloy 3003 were corrosion tested in a commercial (Fleetguard DCA-4) supplemental coolant additive (SCA) package modified by varying the potassium nitrate level.</div> <div class="htmlview paragraph">Electrochemical techniques were used to determine the stability of the passive film as a function of nitrate concentration. Cyclic potentiodynamic polarization and cyclic galvanostaircase polarization were the principle techniques used and compared. In the presence of the other inhibitors, the passive film stability did not change as the nitrate concentration varied. The corrosion resistance of each alloy was more dependent on the alloy chemistry with 3003 being the most resistant and 319 being the least. The two electrochemical techniques provided results consistent with each other.</div> <div class="htmlview paragraph">With the introduction of advanced materials and processes to the heavy duty diesel engine, the challenge in formulating a coolant is to provide adequate protection for all the materials in the cooling system. Cast and wrought aluminum alloys are increasingly being used or are being considered for use in such components as manifolds, pump housings, and radiators. In the past, silicates have been used in coolants to provide protection to aluminum alloys, however overconcentration of the SCA has lead to silicate dropout in the form of a gel which interferes with coolant flow and heat transfer. The use of a low silicate phosphate/molybdate based additive package is an improvement over the traditional borate/nitrite system, however it still contains substantial amounts of nitrate. Although nitrate is added to improve pitting protection in aluminum, excessive amounts can promote brass cracking.</div> <div class="htmlview paragraph">Gravimetric techniques such as the ASTM D-1384 glassware test, cavitation, and hot surface testing have traditionally been used to develop SCA formulations for heavy duty use. Although electrochemical testing has been used extensively in diverse applications such as nuclear power generation, petrochemical production and industrial coatings development, it has only relatively recently come to be accepted for characterizing material behavior in heavy duty, cooling systems (<span class="xref">1</span>, <span class="xref">2</span>, <span class="xref">3</span>, <span class="xref">4</span> and <span class="xref">5</span>). In addition to the shorter test times for determining an “instantaneous” corrosion rate, valuable information can be obtained as to an alloy's natural passivity and the effectiveness of inhibitors in forming protective films (<span class="xref">6</span>). A brief summary of electrochemical testing theory is given in the Appendix and a list of terms and symbols are defined after the Conclusion section.</div> <div class="htmlview paragraph">The purpose of this study is to apply electrochemical corrosion measurement techniques to evaluate the effect of nitrate concentration in Fleetguard's DCA-4 on several typical aluminum alloys, both cast and wrought. It is hoped that the results of this will allow us to specify the minimum amount of nitrate for adequate pitting protection for these alloys. Cyclic potentiodynamic polarization and cyclic galvanostaircase polarization were the primary experimental techniques used to study passivation as a function of nitrate concentration. Potentiodynamic polarization (Tafel plots) were used to measure corrosion current, and hence, rate and polarization resistance. While cyclic potentiodynamic polarization is more commonly used to study repassivation, the kinetic effects on aluminum alloys in particular make the results from this technique dependent on the parameters chosen in making the scan. The pitting potential and the protection potential are dependent, for example on scan rate. To avoid these problems, Hirozawa has proposed the use of the cyclic galvanostaircase technique. This method and its advantages are described in more detail elsewhere (<span class="xref">7</span>, <span class="xref">8</span> and <span class="xref">9</span>). In this study, these two methods will be compared in our specific environment.</div>