Effect of B20 and Low Aromatic Diesel on Transit Bus NOx Emissions Over Driving Cycles with a Range of Kinetic Intensity
Abstract not provided
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
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Engineering Dzyaloshinskii-Moriya interaction in B20 thin-film chiral magnets
Not Available
Turgut, Emrah↗
Impact of a Diesel High Pressure Common Rail Fuel System and Onboard Vehicle Storage on B20 Biodiesel Blend Stability
Adoption of high-pressure common-rail (HPCR) fuel systems, which subject diesel fuels to higher temperatures and pressures, has brought into question the efficacy of ASTM International specifications for biodiesel and biodiesel blend oxidation stability, as well as the lack of any stability parameter for diesel fuel. A controlled experiment was developed to investigate the impact of a light-duty diesel HPCR fuel system on the stability of 20% biodiesel (B20) blends under conditions of intermittent use and long-term storage in a relatively hot and dry climate. B20 samples with Rancimat induction periods (IPs) near the current 6.0-hour minimum specification (6.5 hr) and roughly double the ASTM specification (13.5 hr) were prepared from a conventional diesel and a highly unsaturated biodiesel. Four 2011 model year Volkswagen Passats equipped with HPCR fuel injection systems were utilized: one on B0, two on B20-6.5 hr, and one on B20-13.5 hr. Each vehicle was operated over a one-hour drive cycle in a hot running loss test cell to initially stress the fuel. The cars were then kept at Volkswagen's Arizona Proving Ground for two (35 degrees C average daily maximum) to six months (26 degrees C average daily maximum). The fuel was then stressed again by running a portion of the one-hour dynamometer drive cycle (limited by the amount of fuel in the tank). Fuel rail and fuel tank samples were analyzed for IP, acid number, peroxide content, polymer content, and ester profile. The HPCR fuel pumps were removed, dismantled, and inspected for deposits or abnormal wear. Analysis of fuels collected during initial dynamometer tests showed no impact of exposure to HPCR conditions. Long-term storage with intermittent use showed that IP remained above 3 hours, acid number below 0.3 mg KOH/g, peroxides low, no change in ester profile, and no production of polymers. Final dynamometer tests produced only small changes in fuel properties. Inspection of the HPCR fuel pumps revealed no deposits or abnormal wear for any fuel. The results provide some confidence that the ASTM D7467 stability requirement of 6 hr. minimum IP for B6 to B20 blends provides adequate protection for modern engine fuel systems.
30 DIRECT ENERGY CONVERSION↗
Diesel Particulate Filter Durability Performance Comparison Using Metals Doped B20 vs. Conventional Diesel Part II: Chemical and Microscopic Characterization of Aged DPFs
This project's objective was to generate experimental data to evaluate the impact of metals doped B20 on diesel particle filter (DPF) ash loading and performance compared to that of conventional petrodiesel. The effect of metals doped B20 vs. conventional diesel on a DPF was quantified in a laboratory controlled accelerated ash loading study. The ash loading was conducted on two DPFs - one using ULSD fuel and the other on B20 containing metals dopants equivalent to 4 ppm B100 total metals. Engine oil consumption and B20 metals levels were accelerated by a factor of 5, with DPFs loaded to 30 g/L of ash. Details of the ash loading experiment and on-engine DPF performance evaluations are presented in the companion paper (Part I). The DPFs were cleaned, and ash samples were taken from the cleaned material. X-ray Fluorescence (XRF), X-Ray Photoelectron Spectroscopy (XPS) and X-Ray Diffraction (XRD) were conducted on the ash samples. Core samples were taken from the cleaned DPF and were subjected to scanning electron microscope energy dispersive x-ray spectroscopy (SEM-EDS) and XRF analysis. A comparison of the data from the two DPFs is presented. The XRD and XPS analysis showed that the compounds present in the ash from the two DPFs were nearly identical, though differing in concentrations. CaSO4 was the biggest component of the ash from both DPFs. The metals doped B20 fuel resulted in ash with similar characteristics to that deposited by the lube oil and did not appear to have any deleterious physical effects on the DPF substrate (did not penetrate the substrate).
ADVANCED PROPULSION SYSTEMS,BIOMASS FUELS↗
Local structure and magnetic properties of B2- and B20-like ultrathin Mn films grown on Si(001)
The structural and magnetic properties of ultrathin Mn layers deposited onto Si(001) by molecular beam epitaxy at low temperature are reported. X-ray absorption fine structure studies reveal that the structure of the silicide layer that forms depends on the growth temperature of the capping layer. A capping layer grown at 200 C on 0.35-monolayer (ML) Mn results in a metastable MnSi phase with a B2-like (CsCl) structure, whereas a cap grown at room temperature on 0.5 ML followed by annealing at 200 C produces a lower coordinated MnSi phase with a B20-like structure. Increasing the Mn thickness from 0.5 to 4 monolayers does not trigger a structural transformation but drives the structure closer to MnSi-B20. The sample with B2-like structure has the largest Mn magnetic moment of 0.33 {mu}{sub B}/Mn at T = 2 K, and a Curie temperature T{sub c} above 250 K. MnSi-B20 layers showed lower moments and much lower T{sub c}'s, in line with those reported for MnSi-B20 thin films.
36 MATERIALS SCIENCE↗
Diesel Particulate Filter Durability Performance Comparison Using Metals Doped B20 vs. Conventional Diesel Part I: Accelerated Ash Loading and DPF Performance Evaluation
The project objective was to generate experimental data to evaluate the impact of metals doped B20 on DPF ash loading and performance compared to that of conventional petrodiesel. Accelerated ash loading was conducted on two DPFs - one exposed to regular diesel fuel and the other to B20 containing metal dopants equivalent to 4 ppm B100 total metals (currently total metals are limited to 10 ppm in ASTM D6751, the standard for B100). Periodic performance evaluations were conducted on the DPFs at 10 g/L ash loading intervals. After the evaluations at 30 g/L, the DPF was cleaned with a commercial DPF cleaning machine and another round of DPF evaluations were conducted. A comparison of the effect of ash loading with the two fuels and DPF cleaning is presented. The metals doped B20 fuel resulted in ash that was similar to that deposited when exposed to ULSD (lube oil ash) and exhibited similar ash cleaning removal efficiency. Metals doped B20 resulted in faster ash accumulation within the DPF, as expected, but did not appear to have a negative effect on DPF pressure drop or regeneration rates (up to 30 g/L of ash) or exhibit deleterious physical effects on the DPF substrate.
ADVANCED PROPULSION SYSTEMS,BIOMASS FUELS↗
Chiral Magnetism and High-Temperature Skyrmions in B20-Ordered Co-Si
Magnets with chiral crystal structures and helical spin structures have recently attracted much attention as potential spin-electronics materials, but their relatively low magnetic-ordering temperatures are a disadvantage. While cobalt has long been recognized as an element that promotes high-temperature magnetic ordering, most Co-rich alloys are achiral and exhibit collinear rather than helimagnetic order. Crystallographically, the B20-ordered compound CoSi is an exception due to its chiral structure, but it does not exhibit any kind of magnetic order. Here, we use nonequilibrium processing to produce B20-ordered Co 1+ x Si 1₋ x with a maximum Co solubility of x = 0.043. Above a critical excess-Co content x c = 0.028 ), the alloys are magnetically ordered, and for x = 0.043, a critical temperature $T_c$ = 328 K is obtained, the highest among all B20-type magnets. The crystal structure of the alloy supports spin spirals caused by Dzyaloshinskii-Moriya interactions, and from magnetic measurements we estimate that the spirals have a periodicity of about 17 nm. In this work, our density-functional calculations explain the combination of high magnetic-ordering temperature and short periodicity in terms of a quantum phase transition where excess-cobalt spins are coupled through the host matrix.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Structural properties and recrystallization effects in ion beam modified B20-type FeGe films
Disordered iron germanium (FeGe) has recently garnered interest as a testbed for a variety of magnetic phenomena as well as for use in magnetic memory and logic applications. This is partially owing to its ability to host skyrmions and antiskyrmions—nanoscale whirlpools of magnetic moments that could serve as information carriers in spintronic devices. In particular, a tunable skyrmion–antiskyrmion system may be created through precise control of the defect landscape in B20-phase FeGe, motivating the development of methods to systematically tune disorder in this material and understand the ensuing structural properties. To this end, we investigate a route for modifying magnetic properties in FeGe. In particular, we irradiate epitaxial B20-phase FeGe films with 2.8 MeV Au 4+ ions, which creates a dispersion of amorphized regions that may preferentially host antiskyrmions at densities controlled by the irradiation fluence. To further tune the disorder landscape, we conduct a systematic electron diffraction study with in situ annealing, demonstrating the ability to recrystallize controllable fractions of the material at temperatures ranging from ~150 to 250°C. Finally, we describe the crystallization kinetics using the Johnson–Mehl–Avrami–Kolmogorov model, finding that the growth of crystalline grains is consistent with diffusion-controlled one-to-two dimensional growth with a decreasing nucleation rate.
36 MATERIALS SCIENCE↗
Unusual magnetoresistance in cubic B20 Fe 0.85 Co 0.15 Si chiral magnets
The B20 chiral magnets with broken inversion symmetry and C 4 rotation symmetry have attracted much attention. The broken inversion symmetry leads to the Dzyaloshinskii–Moriya that gives rise to the helical and Skyrmion states.Wereport the unusual magnetoresistance (MR) of B20 chiral magnet Fe 0.85 Co 0.15 Si that directly reveals the broken C 4 rotation symmetry and shows the anisotropic scattering by Skyrmions with respect to the current directions. The intimacy between unusual MR and broken symmetry is well confirmed by theoretically studying an effective Hamiltonian with spin–orbit coupling. In conclusion, the unusual MR serves as a transport signature for the Skyrmion phase.
36 MATERIALS SCIENCE↗
Possible quadrupole-order-driven commensurate-incommensurate phase transition in B20 CoGe
For this study, the B20-type cobalt germanide CoGe was investigated by measuring the specific heat, resistivity, and 59 Co nuclear magnetic resonance (NMR). We observed a phase transition at T Q = 13.7 K, evidenced by a very narrow peak of the specific heat and sharp changes of the nuclear spin-spin (T 2 –1 ) and spin-lattice ( T 1 – 1 ) relaxation rates. The fact that the entropy release is extremely small and the Knight shift is almost independent of temperature down to low temperatures as anticipated in a paramagnetic metal indicates that the T Q transition is of nonmagnetic origin. In addition, we detected a crossover scale T 0 ~ 30 K below which the resistivity and the NMR linewidth increase, and T 1 –1 is progressively distributed in space, that is, a static and dynamical spatial inhomogeneity develops. While the order parameter for the T Q transition remains an open question, a group-theoretical analysis suggests that the finite electric quadrupole density arising from the low local site symmetry at cobalt sites could drive the crystal symmetry lowering from the P2 1 3 symmetry that is commensurate to the R3 symmetry with an incommensurate wave vector, which fairly well accounts for the T Q transition. The quadrupole-order-driven commensurate-incommensurate phase transition may be another remarkable phenomenon arising from the structural chirality inherent in the noncentrosymmetric B20 family.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Magnetic moments and spin structure in single-phase B20 Co 1+x Si 1-x (x = 0.043)
Neutron powder diffraction (NPD) and x-ray magnetic circular dichroism (XMCD) spectroscopy are employed to investigate the magnetism and spin structure in single-phase B20 Co 1.043 Si 0.957 . The magnetic contributions to the NPD data measured in zero fields are consistent with the helical order among the allowed spin structures derived from group theory. The magnitude of the magnetic moment is (0.3 ± 0.1) μ B /Co according to NPD, while the surface magnetization probed by XMCD at 3 kOe is (0.18–0.31) μ B /Co. Both values are substantially larger than the bulk magnetization of 0.11 μ B /Co determined from magnetometry at 70 kOe and 2 K. Finally, these experimental data indicate the formation of a helical spin phase and the associated conical states in high magnetic fields.
36 MATERIALS SCIENCE↗
B20 to B100 Blends as Heating Fuels
Biodiesel is mono-alkyl esters of long chain fatty acids derived from naturally occurring oils or fats which conform to ASTM D6751 specifications. Biodiesel refers to the pure fuel before blending with traditional distillate type petroleum-based fuels such as diesel fuel or home heating oil (petrodiesel). Biodiesel blends are denoted as, "BXX" with "XX" representing the percentage of biodiesel by volume contained in the blend (i.e.: B20 is 20% biodiesel, 80% petrodiesel). Biodiesel offers a near-term opportunity to displace petroleum-based heating oil with a low carbon, renewable fuel. Biodiesel can be made from a variety of domestically produced oils and fats such as commonly available vegetable oils or animal fats as well as other oils such as used frying oils, reclaimed distillers corn oil from ethanol plants, algal oils, etc. In the US, about half the biodiesel is made from soybean oil, with the remainder about evenly split between canola oil, animal fats, used cooking oils, and distillers corn oil.
09 BIOMASS FUELS↗
Quality analysis of wintertime B6–B20 biodiesel blend samples collected in the United States
Explore the source record for details and available documents.
33 ADVANCED PROPULSION SYSTEMS↗
Unconventional superconducting pairing in a B20 multifold Weyl fermion semimetal
Not provided.
Materials Science↗
Biodiesel Impact on Engine Lubricant Dilution During Active Regeneration of Aftertreatment Systems
Experiments were conducted with ultra low sulfur diesel (ULSD) and 20% biodiesel blends (B20) to compare lube oil dilution levels and lubricant properties for systems using late in-cylinder fuel injection for aftertreatment regeneration. Lube oil dilution was measured by gas chromatography (GC) following ASTM method D3524 to measure diesel content, by Fourier transform infrared (FTIR) spectrometry following a modified ASTM method D7371 to measure biodiesel content, and by a newly developed back-flush GC method that simultaneously measures both diesel and biodiesel. Heavy-duty (HD) engine testing was conducted on a 2008 6.7L Cummins ISB equipped with a diesel oxidation catalyst (DOC) and diesel particle filter (DPF). Stage one of engine testing consisted of 10 consecutive repeats of a forced DPF regeneration event. This continuous operation with late in-cylinder fuel injection served as a method to accelerate lube-oil dilution. Stage two consisted of 16 hours of normal engine operation over a transient test cycle, which created an opportunity for any accumulated fuel in the oil sump to evaporate. Light duty (LD) vehicle testing was conducted on a 2010 VW Jetta equipped with DOC, DPF and a NOx storage catalyst (NSC). Vehicle testing comprised approximately 4,000 miles of operation on a mileage-accumulation dynamometer (MAD) using the U.S. Environmental Protection Agency's Highway Fuel Economy Cycle because of the relatively low engine oil and exhaust temperatures, and high DPF regeneration frequency of this cycle relative to other cycles examined. Comparison of the lube oil dilution analysis methods suggests that D3524 does not measure dilution by biodiesel. The new back-flush GC method provided analysis for both diesel and biodiesel, in a shorter time and with lower detection limit. Thus all lube oil dilution results in this paper are based on this method. Analysis of the HD lube-oil samples showed only 1.5% to 1.6% fuel dilution for both fuels during continuous operation under DPF regeneration events. During the second stage of HD testing, the ULSD lube-oil dilution levels fell from 1.5% to 0.8%, while for B20, lube-oil dilution levels fell from 1.6% to 1.0%, but the fuel in the oil was 36% biodiesel. For the LD vehicle tests, the frequency of DPF regeneration events was observed to be the same for both ULSD and B20. No significant difference between the two fuels' estimated soot loading was detected by the engine control unit (ECU), although a 23% slower rate of increase in differential pressure across DPF was observed with B20. It appears that the ECU estimated soot loading is based on the engine map, not taking advantage of the lower engine-out particulate matter from the use of biodiesel. After 4,000 miles of LD vehicle operation with ULSD, fuel dilution in the lube-oil samples showed total dilution levels of 4.1% diesel. After 4,000 miles of operation with B20, total fuel in oil dilution levels were 6.7% consisting of 3.6% diesel fuel and 3.1% biodiesel. Extrapolation to the 10,000-mile oil drain interval with B20 suggests that the total fuel content in the oil could reach 12%, compared to 5% for operation on ULSD. Analysis of the oil samples also included measurement of total acid number, total base number, viscosity, soot, metals and wear scar; however, little difference in these parameters was noted.
09 BIOMASS FUELS↗
Evaluation of fuel-borne sodium effects on a DOC-DPF-SCR heavy-duty engine emission control system: Simulation of full-useful life
Here we report that for renewable fuels to displace petroleum, they must be compatible with emissions control devices. Pure biodiesel contains up to 5 ppm Na + K and 5 ppm Ca + Mg metals, which have the potential to degrade diesel emissions control systems. This study aims to address these concerns, identify deactivation mechanisms, and determine if a lower limit is needed. Accelerated aging of a production exhaust system was conducted on an engine test stand over 1001 h using 20% biodiesel blended into ultra-low sulfur diesel (B20) doped with 14 ppm Na. This Na level is equivalent to exposure to Na at the uppermost expected B100 value in a B20 blend for the system full-useful life. During the study, NOx emissions exceeded the engine certification limit of 0.33 g/bhp-hr before the 435,000-mile requirement. Replacing aged diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) devices with new degreened parts showed that each device contributed equally to the NOx increase. Following this systems-based evaluation, a detailed investigation of the individual components was completed. Na was determined to have minimal impact on DOC activity. For this system, it is estimated that B20-Na resulted in 50% more ash into the DPF. However, the Na did not diffuse into the cordierite DPF nor degrade its mechanical properties. The SCR degradation was found to be caused by a small amount of precious group metals (PGM) contamination that increased NH3 oxidation, and lowered NOx reduction. Therefore, we determined that the primary effect of Na in this study is through increased ash in the DPF rather than deactivation of the catalytic activity.
42 ENGINEERING↗
Emissions From Various Biodiesel Sources Compared to a Range of Diesel Fuels in DPF Equipped Diesel Engines
The purpose of this study was to measure the impact of various sources of petroleum-based and bio-based diesel fuels on regulated emissions and fuel economy in diesel particulate filter (DPF) equipped diesel engines. Two model year 2008 diesel engines were tested with nine fuels including a certification ultra-low sulfur diesel (ULSD), local ULSD, high aromatic ULSD, low aromatic ULSD, and twenty percent blends of biodiesel derived from algae, camelina, soy, tallow, and yellow grease. Regulated emissions were measured over the heavy duty diesel transient test cycle. Measurements were also made of DPF-out particle size distribution and total particle count from a 13-mode steady state test using a fast mobility particle sizer. Test engines were a 2008 Cummins ISB and a 2008 International Maxx Force 10, both equipped with actively regenerated DPFs. Fuel consumption was roughly 2% greater over the transient test cycle for the B20 blends versus certification ULSD in both engines, consistent with the slightly lower energy content of biodiesel. Unlike studies conducted on older model engines, these engines equipped with diesel oxidation catalysts and DPFs showed small or no measurable fuel effect on the tailpipe emissions of total hydrocarbons (THC), carbon monoxide (CO) and particulate matter (PM). No differences in particle size distribution or total particle count were seen in a comparison of certification ULSD and B20 soy, with the exception of engine idling conditions where B20 produced a small reduction in the number of nucleation mode particles. In the Cummins engine, B20 prepared from algae, camelina, soy, and tallow resulted in an approximately 2.5% increase in nitrogen oxides (NO{sub x}) compared to the base fuel. The International engine demonstrated a higher degree of variability for NO{sub x} emissions, and fuel effects could not be resolved (p > 0.05). The group of petroleum diesel test fuels produced a range of NO{sub x} emissions very similar to that caused by blending of biodiesel. Test cycles where an active regeneration of the DPF occurred resulted in a nearly threefold increase in NO{sub x} emissions and a 15% increase in fuel consumption. The full quantification of DPF regeneration events further complicates the accurate calculation of fuel impacts on emissions and fuel consumption.
02 PETROLEUM↗
Missouri Soybean Association Biodiesel Demonstration Project: Final Report
The Missouri Soybean Association (MSA) and the National Biodiesel Board (NBB) partnered together to implement the MSA Biodiesel Demonstration project under a United States Department of Energy (DOE) grant. The goal of this project was to provide decision makers and fleet managers with information that could lead to the increased use of domestically produced renewable fuels and could reduce the harmful impacts of school bus diesel exhaust on children. This project was initiated in September 2004 and completed in April 2011. The project carried out a broad range of activities organized under four areas: 1. Petroleum and related industry education program for fuel suppliers; 2. Fleet evaluation program using B20 with a Missouri school district; 3. Outreach and awareness campaign for school district fleet managers; and 4. Support of ongoing B20 Fleet Evaluation Team (FET) data collection efforts with existing school districts. Technical support to the biodiesel industry was also provided through NBB’s Troubleshooting Hotline. The hotline program was established in 2008 to troubleshoot fuel quality issues and help facilitate smooth implementation of the RFS and is described in greater detail under Milestone A.1 - Promote Instruction and Guidance on Best Practices. As a result of this project’s efforts, MSA and NBB were able to successfully reach out to and support a broad spectrum of biodiesel users in Missouri and New England. The MSA Biodiesel Demonstration was funded through a FY2004 Renewable Energy Resources Congressional earmark. The initial focus of this project was to test and evaluate biodiesel blends coupled with diesel oxidation catalysts as an emissions reduction technology for school bus fleets in the United States. The project was designed to verify emissions reductions using Environmental Protection Agency (EPA) protocols, then document – with school bus fleet experience – the viability of utilizing B20 blends. The fleet experience was expected to support ongoing industry efforts to collect existing data and to increase awareness and knowledge among school district fleet managers. However, three years into the project, the original intent of the engine verification was no longer deemed by equipment manufacturers to be of sufficient economic interest to enter into a partnership. In response, MSA requested a project extension and re-scope to eliminate the aftermarket equipment verification and replace it with a petroleum education program. The revised project maintained four task areas with the following modifications. The first component was directed at increasing national compliance with newly initiated state level fuel blend mandates through a distributor education program. Component two was modified to eliminate the verification element and, instead, document operational data from biodiesel use in a district school bus fleet. Components three and four were unchanged and maintained their purpose of expanding upon the existing knowledge base of biodiesel use in school bus fleets.
09 BIOMASS FUELS↗