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A program has been completed to evaluate ultra-low sulfur diesel fuels and passive diesel particulate filters (DPFs) in truck and bus fleets operating in southern California. The fuels, ECD and ECD-1, are produced by ARCO (a BP Company) and have less than 15 ppm sulfur content. Vehicles were retrofitted with two types of catalyzed DPFs, and operated on ultra-low sulfur diesel fuel for over one year. Exhaust emissions, fuel economy and operating cost data were collected for the test vehicles, and compared with baseline control vehicles. Regulated emissions are presented from two rounds of tests. The first round emissions tests were conducted shortly after the vehicles were retrofitted with the DPFs. The second round emissions tests were conducted following approximately one year of operation. Several of the vehicles retrofitted with DPFs accumulated well over 100,000 miles of operation between test rounds.

Cavitation plays a significant role in high pressure diesel injectors. However, cavitation is difficult to measure under realistic conditions. X-ray phase contrast imaging has been used in the past to study the internal geometry of fuel injectors and the structure of diesel sprays. In this paper we extend the technique to make in-situ measurements of cavitation inside unmodified diesel injectors at pressures of up to 1200 bar through the steel nozzle wall. A cerium contrast agent was added to a diesel surrogate, and the changes in x-ray intensity caused by changes in the fluid density due to cavitation were measured. Without the need to modify the injector for optical access, realistic injection and ambient pressures can be obtained and the effects of realistic nozzle geometries can be investigated. A range of single and multi-hole injectors were studied, both sharp-edged and hydro-ground. Cavitation was observed to increase with higher rail pressures.

The salient features of modern gasoline direct injection include cavitation, flash boiling, and plume/plume interaction, depending on the operating conditions. These complex phenomena make the prediction of the spray behavior particularly difficult. The present investigation combines mass-based experimental diagnostics with an advanced, in-house modeling capability in order to provide a multi-faceted study of the Engine Combustion Network’s Spray G injector. First, x-ray tomography is used to distinguish the actual injector geometry from the nominal geometry used in past works. The actual geometry is used as the basis of multidimensional CFD simulations which are compared to x-ray radiography measurements for validation under cold conditions. The influence of nozzle diameter and corner radius are of particular interest. Next, the model is used to simulate flash-boiling conditions, in order to understand how the cold flow behavior corresponds to flashing performance.

A gas chromatographic technique was used to determine the vapor pressures of blends of six candidate diesel fuel oxygenates with three diesel fuels at 0, 5, 10, 30, and 100 percent blend levels. Both the oxygenates and the diesel fuels were selected to represent a variety of chemical compositions. The vapor pressures were determined over a range of temperatures from -30 C to +30 C. In each case the fraction of the vapor pressure derived from the oxygenate and the fuel was identified. The vapor pressure results showed that there were significant deviations from ideality, leading to both higher and lower vapor pressures than would be predicted from Raoult's Law. These results are significant for fire safety and evaporative emissions as well as for a more basic understanding of the behavior of these blends. Data were also obtained on the heats of vaporization for each of the blends.

An Advanced Automotive Manikin (ADAM), is used to evaluate liquid cooling garments (LCG) for advanced space suits for extravehicular applications and launch and entry suits. The manikin is controlled by a finite-element physiological model of the human thermoregulatory system. ADAM's thermal response to a baseline LCG was measured.The local effectiveness of the LCG was determined. These new thermal comfort tools permit detailed, repeatable measurements and evaluation of LCGs. Results can extend to other personal protective clothing including HAZMAT suits, nuclear/biological/ chemical protective suits, fire protection suits, etc.

People who wear protective uniforms that inhibit evaporation of sweat can experience reduced productivity and even health risks when their bodies cannot cool themselves. This paper describes a new sweating manikin and a numerical model of the human thermoregulatory system that evaluates the thermal response of an individual to transient, non-uniform thermal environments. The physiological model of the human thermoregulatory system controls a thermal manikin, resulting in surface temperature distributions representative of the human body. For example, surface temperatures of the extremities are cooler than those of the torso and head. The manikin contains batteries, a water reservoir, and wireless communications and controls that enable it to operate as long as 2 hours without external connections. The manikin has 120 separately controlled heating and sweating zones that result in high resolution for surface temperature, heat flux, and sweating control.

Propagation-based and phase-enhanced x-ray imaging was developed as a unique metrology technique to visualize the internal structure of high-pressure fuel injection nozzles. We have visualized the microstructures inside 200-μm fuel injection nozzles in a 3-mm-thick steel housing using this novel technique. Furthermore, this new x-ray-based metrology technique has been used to directly study the highly transient needle motion in the nozzles in situ and in real-time, which is virtually impossible by any other means. The needle motion has been shown to have the most direct effect on the fuel jet structure and spray formation immediately outside of the nozzle. In addition, the spray cone-angle has been perfectly correlated with the numerically simulated fuel flow inside the nozzle due to the transient nature of the needle during the injection.

An accurate prediction of internal nozzle flow in fuel injector offers the potential to improve predictions of spray computational fluid dynamics (CFD) in an engine, providing a coupled internal-external calculation or by defining better rate of injection (ROI) profile and spray angle information for Lagrangian parcel computations. Previous research has addressed experiments and computations in transparent nozzles, but less is known about realistic multi-hole diesel injectors compared to single axial-hole fuel injectors. In this study, the transient injector opening and closing is characterized using a transparent multi-hole diesel injector, and compared to that of a single axial hole nozzle (ECN Spray D shape). A real-size five-hole acrylic transparent nozzle was mounted in a high-pressure, constant-flow chamber. Internal nozzle phenomena such as cavitation and gas exchange were visualized by high-speed long-distance microscopy.

Recent advances in fuel-cell technology and low-emission, direct-injection spark-ignition and diesel engines for vehicles could significantly change the transportation vehicle power plant landscape in the next decade or so. This paper is a scoping study that compares total fuel cycle options for providing power to personal transport vehicles. The key question asked is, “How much of the energy from the fuel feedstock is available for motive power?” Emissions of selected criteria pollutants and greenhouse gases are qualitatively discussed. This analysis illustrates the differences among options; it is not intended to be exhaustive. Cases considered are hydrogen fuel from methane and from iso-octane in generic proton-exchange membrane (PEM) fuel-cell vehicles, methane and iso-octane in spark-ignition (SI) engine vehicles, and diesel fuel (from methane or petroleum) in direct-injection (DI) diesel engine vehicles.

Quantitative measurements of direct injection fuel spray density and mixing are difficult to achieve using optical diagnostics, due to the substantial scattering of light and high optical density of the droplet field. For multi-hole sprays, the problem is even more challenging, as it is difficult to isolate a single spray plume along a single line of sight. Time resolved x-ray radiography diagnostics developed at Argonne's Advanced Photon Source have been used for some time to study diesel fuel sprays, as x-rays have high penetrating power in sprays and scatter only weakly. Traditionally, radiography measurements have been conducted along any single line of sight, and have been applied to single-hole and group-hole nozzles with few plumes. In this new work, we extend the technique to multi-hole gasoline direct injection sprays.

Using synchrotron x-radiography and mass deconvolution techniques, this work reveals strikingly interesting structural and dynamic characteristics of the direct injection (DI) gasoline hollow-cone sprays in the near-nozzle region. Employed to measure the sprays, x-radiography allows quantitative determination of the fuel distribution in this optically impenetrable region with a time resolution of better than 1 μs, revealing the most detailed near-nozzle mass distribution of a DI gasoline fuel spray ever detected. Based on the x-radiographs of the spray collected from four different perspectives, enhanced mathematical and numerical analyses were developed to deconvolute the mass density of the gasoline hollow-cone spray. This leads to efficient and accurate regression curve fitting of the measured experimental data to obtain essential parameters of the density distribution that are then used in reconstructing the cross-sectional density distribution at various times and locations.

Most previous measurements of diesel sprays have yielded few details regarding the near-nozzle structure of the sprays. X-ray radiography measurements have provided quantitative, time-resolved measurements of spray behavior, but the radiography data are projections of the actual fuel distribution. In this study, diesel sprays from two axial, single-hole nozzles are measured using x-ray radiography from several viewing angles. A model-based reconstruction is used to determine the actual density distribution from the projected data. The spray from the hydroground nozzle is eccentric and relatively dense, while the spray from the non-hydroground nozzle is asymmetric and far less dense. Even several mm from the nozzles, the calculated density values are high enough to call into question the assumptions underlying many standard CFD spray models.

Due to its high efficiency and superior durability the diesel engine is again becoming a prime candidate for future light-duty vehicle applications within the United States. While in Europe the overall diesel share exceeds 40%, the current diesel share in the U.S. is 1%. Despite the current situation and the very stringent Tier 2 emission standards, efforts are being made to introduce the diesel engine back into the U.S. market. In order to succeed, these vehicles have to comply with emissions standards over a 120,000 miles distance while maintaining their excellent fuel economy. The availability of technologies such as high-pressure common-rail fuel systems, low sulfur diesel fuel, NOx adsorber catalysts (NAC), and diesel particle filters (DPFs) allow the development of powertrain systems that have the potential to comply with the light-duty Tier 2 emission requirements. In support of this, the U.S.

The air-conditioning system can significantly impact the fuel economy and tailpipe emissions of automobiles. If the peak soak temperature of the passenger compartment can be reduced, the air-conditioner compressor can potentially be downsized while maintaining human thermal comfort. Solar reflective film is one way to reduce the peak soak temperature by reducing the solar heat gain into the passenger compartment. A 3M non-metallic solar reflective film (SRF) was tested in two minivans and two sport utility vehicles (SUV). The peak soak temperature was reduced resulting in a quicker cooldown. Using these data, a reduction in air-conditioner size was estimated and the fuel economy and tailpipe emissions were predicted.

The nodal force based Battelle structural stress method has shown its mesh insensitivity in the stress analysis of spot welds as well as fusion welds. In the conventional structural stress simulation procedure, the structural stress is calculated at the nodes along the nugget periphery. However, implementing a nugget into each spot weld is cumbersome and time consuming not only in preparing mesh for FE analysis but also in preparing a series of structural stress calculation after finishing the FE analysis. Therefore, the efficiency of the current Battelle structural stress practice for spot welds can be improved significantly for structures with a large number of spot welds. The simplified modeling procedure presented here delivers reliable structural stresses at spot welds and these stresses can then be utilized for fatigue life prediction using a master S-N Curve approach that is applicable to wide range of spot welding techniques.

A key to the success of the national hydrogen and fuel cell codes and standards developments efforts to date was the creation and implementation of national templates through which the U.S. Department of Energy (DOE), the National Renewable Energy Laboratory (NREL), and the major standards development organizations (SDOs) and model code organizations coordinate the preparation of critical standards and codes for hydrogen and fuel cell technologies and applications and maintain a coordinated national agenda for hydrogen and fuel cell codes and standards

This paper summarizes the several of the studies in the Environmental Science Program being sponsored by DOE's Office of Heavy Vehicle Technologies (OHVT) through the National Renewable Energy Laboratory (NREL). The goal of the Environmental Science Program is to understand atmospheric impacts and potential health effects that may be caused by the use of petroleum-based fuels and alternative transportation fuels from mobile sources. The Program is regulatory-driven, and focuses on ozone, airborne particles, visibility and regional haze, air toxics, and health effects of air pollutants. Each project in the Program is designed to address policy-relevant objectives. Current projects in the Environmental Science Program have four areas of focus: improving technology for emissions measurements; vehicle emissions measurements; emission inventory development/improvement; ambient impacts, including health effects.

This paper summarizes current work in the Environmental Science & Health Effects (ES&HE) Program being sponsored by DOE's Office of Heavy Vehicle Technologies (OHVT) through the National Renewable Energy Laboratory (NREL). The program is regulatory-driven, and focuses on ozone, airborne particles, visibility and regional haze, air toxics, and health effects of air pollutants. The goal of the ES&HE Program is to understand atmospheric impacts and potential health effects that may be caused by the use of petroleum-based and alternative transportation fuels. Each project in the program is designed to address policy-relevant objectives. Studies in the ES&HE Program have four areas of focus: improving technology for emissions measurements; vehicle emissions measurements, emission inventory development/improvement; and ambient impacts, including health effects.

Hydrogen-powered vehicles offer the promise of significantly reducing the amount of pollutants that are expelled into the environment on a daily basis by conventional hydrocarbon-fueled vehicles. While very promising from an environmental viewpoint, the technology and systems that are needed to store the hydrogen (H2) fuel onboard and deliver it to the propulsion system are different from what consumers, mechanics, fire safety personnel, the public, and even engineers currently know and understand. As the number of hydrogen vehicles increases, the likelihood of a rollover or collision of one of these vehicles with another vehicle or a barrier will also increase.

The Diesel Emission Control - Sulfur Effects (DECSE) program is a joint U.S. government/industry program that studies the impact of diesel sulfur levels on four types of emission control systems. One type of system, Diesel Particulate Filters (DPF), removes particulate matter (PM) from the exhaust stream by collection on a filter. The critical operating issue for DPF technology is the cleaning or regeneration of the control device (by oxidation of the collected PM) to prevent plugging. However, oxidation of sulfur in the exhaust forms sulfates, which are measured as PM. Two types of tests are conducted to evaluate the impacts of fuel sulfur on DPF performance: (1) emissions tests for PM components and gases, and (2) experiments to measure the effect of fuel sulfur on the regeneration temperature required by the filter devices.