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April 2011

April 29, 2011

CALSTART launching E-Truck Task Force

CALSTART, the California operating division of WestStart, a North American advanced transportation technologies consortium, is creating an E-Truck Task Force (E-TTF) to accelerate the development of electric and zero-emissions medium-and heavy-duty vehicles.

CALSTART supports all clean fuels and technologies, and often creates targeted work in emerging sectors of our industry to provide focus and assistance to its growth. It did so with hybrid trucks, renewable natural gas, fuel cell buses, ethanol fueling stations, EV infrastructure and other segments.

The E-Truck Task Force (E-TTF) will include a cross section of fleet users (both those who have e-trucks and those considering purchase) and e-truck vehicle makers and suppliers. The E-TTF will identify key areas of needed action, develop joint industry approaches to address barriers and work collaboratively to help move the industry forward.

The E-TTF will meet periodically throughout this spring and summer, leading to a larger E-Truck Summit session on October 11th as part of the HTUF (Hybrid Truck Users Forum) 2012 National Conference in Baltimore.

April 29, 2011 in Brief | Permalink | Comments (1) | TrackBack

Opposed-piston engine maker Pinnacle initially targeting developing markets, with vehicles expected in 2013

Startup Pinnacle Engines, the developer of a four-stroke, spark-ignited (SI), opposed-piston, sleeve-valve architecture engine (earlier post), is initially targeting lower power applications (such as tuk tuks) in developing markets in its commercialization strategy. The company has signed a licensing and joint development agreement with a major, as yet unnamed, Asian vehicle OEM, with products expected to be available in the first quarter of 2013.

Pinnacle has logged more than 500 hours of operation on its research engine so far (in multiple builds, but with the same components). Pinnacle says its engine achieves 30-50% better fuel economy in various drive cycle comparisons without the large cost penalty that can be associated with significant fuel economy improvement. The performance of the Pinnacle Engines design has been independently verified by FEV, Inc., a Pinnacle Engines development partner.

The core of Pinnacle’s technology resides in the engine architecture and what it calls the Cleeves Cycle. (James (Monty) Cleeves is the Founder, President, and CTO of Pinnacle.) As it is just emerging from stealth mode, with more IP work to be done, the company is still somewhat guarded about details on the Cleeves Cycle and the engine, Cleeves and Tom Covington, Pinnacle’s VP marketing and special projects, said in an interview.

(The company has had one US patent awarded (#7,921,817, on 12 April 2011) on the basic engine architecture, and has a number of other patent applications filed and pending.)

The reason you do opposed pistons is that the surface area to volume ratio of the combustion chamber is small. The heat that you waste trying to cool valves and stems [in a conventional engine] isn’t relevant.

The adiabatic engine guys in the 80s had the same concept—keep the heat in [for more efficiency]. But they didn’t do anything special with the heat that they kept in; that’s what we’re doing differently. We have a big expansion ratio compared to a traditional spark engine and so we can do something with this heat that we’ve saved. We still have the same sort of power densities as the traditional engines. We don’t have the hit that the Atkinson cycles do. We net diesel-like efficiencies on this teeny gasoline engine.

—Monty Cleeves

Using a four-stroke architecture is inherently easier from an emissions perspective, Cleeves said, noting that by using this design, Pinnacle can isolate the lubrication circuit from the air flow, which is traditionally a problem with opposed piston designs. The Pinnacle engine using a sliding sleeve valve system: intake liner, exhaust liner, spark plug in the middle.

The sleeve valve fits between the piston and the cylinder wall in the cylinder where it rotates and/or slides. The sleeve valve moves independently from the piston so that openings in the valve align with the inlet and exhaust ports in the cylinder at proper stages in the combustion cycle.

The company does say broadly that the Cleeves cycle operates on the Otto cycle (constant volume combustion) or Diesel cycle (constant pressure combustion) depending on operating conditions. Additional efficiency improvements will be realized through incorporation of variable valve timing, direct injection, turbocharging, and Pinnacle’s own low-cost variable compression ratio mechanism.

Pinnacle, says Cleeves, uses various attributes resulting from the design of its engine such as optimized breathing applied to turbulence generation and the retention of heat to cause the engine to run in an operating mode differing from conventional engines.

We’re not interested in the real high power efficiency, because if you look at a drive cycle, you never run there. That 10 hp engine is running at 4 hp most of the time. Having a high peak efficiency at 10 hp doesn’t help you if your efficiency at 4 hp isn’t very good. We focus on making it efficient where people use it. Our peak numbers at those lighter loads are not the big 42% numbers, but that’s where we get 30-50% difference between a conventional engine and us. We’ve moved our peak efficiency down where it’s usable.

—Monty Cleeves

The engine, notes Covington, doesn’t require a lot of “whizz bang” technology; the first application is a single-cylinder, single carburetor engine. “It doesn’t require magic.

In terms of emissions, Cleeves said that Pinnacle was close to being able to hit Euro 5 on light vehicles in the developing world markets (the data out of the test cell shows achieving the spec, but Pinnacle is allowing for degradation).

Automotive applications will also likely happen more rapidly in the developing markets, than in the US, Pinnacle suggests.

It’s a lot less expensive to get these engines into production in developing markets, as we can do it a lot faster. We love this engine for automotive, but that’s a totally different ball of wax. It takes a lot more money and a lot more time.

—Tom Covington

Despite the simplicity of the initial single-cylinder application of the architecture, the design offers the opportunity to add in a number of advanced features, such as a variable compression ratio (VCR) mechanism, that are complementary to the technology that is already in the engine.

Today, VCR mechanisms have to worry about interacting with a single crankshaft. Because [the crankshaft] wants to be fixed in position, there are some pretty wild mechanisms [to achieve VCR]. With the opposed piston, we have a fixed crankshaft, and another crankshaft. We can do all sorts of things with that other crankshaft to change the distance between the two pistons. We can make terrific VCR mechanisms that allow us to run a 5:1 compression ratio, put huge amounts of energy into the turbo, boost the inlet manifold pressure to 3, 4, 5 bar, and put out 500 hp in the back of Porsche but actually deliver 50 mpg because you never need that 500 hp. Then you crank up the compression ratio to some huge number and adjust the valve timing, and we can do the Atkinson cycle at those conditions, and deliver net 50 mpg in the 500 hp Porsche turbo. It’s a pretty exciting engine when you get to put all the bells and whistles on.

—Monty Cleeves

Pinnacle says it will publish technical papers during the coming year, and plans to present at the SAE 2012 World Congress.

Resources

April 29, 2011 in Engines | Permalink | Comments (3) | TrackBack

BYD reports plug-in fleet test results; rapid charging not diminishing capacity

E6
BYD all-electric e6 Taxi in service in Shenzhen. Click to enlarge.

In conjunction with the one-year anniversary of its all-electric vehicle Taxi fleet test, BYD announced high-level results of several pilots of its plug-in electric vehicles—the F3DM, e6 and eBUS-12—in fleet testing across the world.

In total, BYD plug-ins have accumulated more than 1.769 million all-electric miles (2.847 million km) and have seen no diminished range or capacity due to rapid-charging. BYD vehicles are estimated to have already saved $360,000 in fuel costs and more than 2.776 million lbs (1.26 million kg) of carbon-dioxide.

50 of BYD’s e6, five-seat crossover vehicles, each with a range of more than 160 miles (300 km) and a top speed of 88 mph (140 km/h), have been in service at Shenzhen-based Pengcheng Electric Taxi Company since 29 April 2010. The Shenzhen e6 Taxi fleet has now accumulated ~1,730,000 all-electric miles (2.77 million kilometers). The distance traveled for single fleet vehicles has reached ~63,000 miles each (>100,000 km).

250 more eTaxis are being delivered to the International University in Shenzhen before August this year. According to collected data, the per-car-fuel-savings is more than $1,167 per Taxi per month (driving an average of 400 km per day). BYD’s all-electric Taxis are expected to help Shenzhen avoid about 133 lbs (or 60.4 kg) of carbon-dioxide emissions per day per taxi. This is an equivalent of 2,425,060 lbs (or 1.1M kg) of carbon-dioxide pollution saved by this fleet in the first year.

BYD said that the most important finding in the e6 fleet testing was that there has been no noticeable energy drop—both driving range and battery performance has been stable in rapid-charging conditions over the 1.73M miles tested.

The results of the e6 fleet, which was continuously rapid charged in 20-30 minutes, provide a proven track record for its Iron-Phosphate battery technology, BYD said.

BYD also reported on its F3DM fleet which BYD launched in its first US tests at the Housing Authority of Los Angeles (HACLA). The F3DM can travel more than 40 miles (64 km) all-electric but can be engaged to act as a Hybrid-Electric (HEV) to extend its range up to 300 miles (483 km). The HACLA fleet has now accumulated ~10,430 miles (16,785 km) all-electric and 14,430 total miles (23,223 km); 4,000 fuel-driven miles when extended range was necessary.

The fleet is achieving an equivalent of 88 mpg (2.67 L/100km) and BYD estimates the per-car-savings—even netting out EV charging and electricity costs—is ~70%. BYD’s dual-mode cars are expected to save HACLA about 37 lbs (16.8 kg) of carbon-dioxide per-day-per-auto when driven to the EV range.

In China, BYD launched an all-electric bus fleet with the eBUS-12 in Shenzhen and Changsha, China in January 2011. These fleets have already accumulated 28,802 all-electric miles (46,380 km) while undergoing a 3-hour-charge of the 324 kWh FE battery. An example of the per-eBUS-savings for Shenzhen’s Bus Line 202 (driving only 200 km per day) is about $2,833 monthly per eBUS. 300 more buses will be delivered to Shenzhen in August of this year. BYD’s all-electric eBUSes save about 708 lbs (322 kg) in carbon-dioxide emissions per eBUS per day.

April 29, 2011 in China, Electric (Battery), Fleets, Plug-ins | Permalink | Comments (17) | TrackBack

Annual American Lung Association report shows continued progress in air quality, but more to be done

The American Lung Association released its annual report on air quality, State of the Air 2011, which includes lists of the nation’s most polluted metropolitan areas. This year’s report finds that the majority of American cities most-polluted by ozone (smog) or year-round particle pollution (soot) have improved, showing continued progress in the cleanup of toxics under the requirements of the Clean Air Act.

However, the report also finds that just over half the nation—154.5 million people—live in areas with levels of ozone and/or particle pollution that are often dangerous to breathe.

All metro areas in the list of the 25 cities most polluted by ozone showed improvement over the previous report, and 15 of those cities experienced the best year yet. All but two of the 25 cities most polluted with year-round particle pollution improved over last year’s report. However, only 11 cities among those most polluted by short-term spikes in particle pollution experienced improvement.

The State of the Air 2011 report grades cities and counties based, in part, on the color-coded Air Quality Index developed by the US Environmental Protection Agency (EPA) to help alert the public to daily unhealthy air conditions. The 12th annual release of the Lung Association’s report uses the most recent EPA data collected from 2007 through 2009 from official monitors for ozone and particle pollution, the two most widespread types of air pollution. Counties are graded for ozone, year-round particle pollution and short-term particle pollution levels. The report also uses EPA’s calculations for year-round particle levels.

The report identified Honolulu, Hawaii and Santa Fe-Espanola, N.M. as the cleanest cities—the only two cities in the nation that were among the cleanest for year-round particle pollution and also had no days when ozone and daily particle pollution levels reached unhealthy ranges.

Nearly 60 million Americans (19.8%) live in counties with too many unhealthy spikes in particle pollution levels, and 18 million people live with unhealthy year-round levels of particle pollution. Particle levels can spike for hours to weeks on end (short-term) or remain at unhealthy levels on average every day (year-round).

Only 10 counties received an “F” for year-round particle pollution. Bakersfield, Calif. tops both lists of cities most-polluted by short-term and annual particle pollution. Bakersfield and Hanford, Calif. were the only two cities where year-round particle levels worsened over the previous report.

State of the Air 2011 finds that nearly half the people in the US (48.2%) live in counties that received an “F” for air quality due to unhealthy ozone levels. Ozone (smog) is the most widespread air pollutant, created by the reaction of sunlight on emissions from vehicles, power plants and other sources. When ozone is inhaled, it irritates the lungs. It can cause immediate health problems and continue days later. Ozone can cause wheezing, coughing, asthma attacks and even premature death.

Los Angeles-Long Beach-Riverside, Calif. remains the metropolitan area with the worst ozone problem, although great improvements have been made since the report was first issued.

The American Lung Association released a bipartisan poll in February that showed Americans overwhelmingly support efforts for even tougher air quality standards, and oppose Congressional action that interferes with the EPA’s ability to update clean air standards.

10 Most Ozone-Polluted Cities

  1. Los Angeles-Long Beach-Riverside, Calif.
  2. Bakersfield-Delano, Calif.
  3. Visalia-Porterville, Calif.
  4. Fresno-Madera, Calif.
  5. Sacramento-Arden-Arcade-Yuba City, Calif.-Nev.
  6. Hanford-Corcoran, Calif.
  7. San Diego-Carlsbad-San Marcos, Calif.
  8. Houston-Baytown-Huntsville, Texas
  9. Merced, Calif.
  10. Charlotte-Gastonia-Salisbury, N.C.-S.C.

10 Cities Most Polluted by Short-term Particle Pollution

  1. Bakersfield-Delano, Calif.
  2. Fresno-Madera, Calif.
  3. Pittsburgh-New Castle, Pa.
  4. Los Angeles-Long Beach-Riverside, Calif.
  5. Salt Lake City-Ogden-Clearfield, Utah
  6. Provo-Orem, Utah
  7. Visalia-Porterville, Calif.
  8. Birmingham-Hoover-Cullman, Ala.
  9. Hanford-Corcoran, Calif.
  10. Logan, Utah-Idaho; Sacramento-Arden-Arcade-Yuba City, Calif.-Nev.

10 Cities Most Polluted by Year-Round Particle Pollution

  1. Bakersfield-Delano, Calif.
  2. Los Angeles-Long Beach-Riverside, Calif.
  3. Phoenix-Mesa-Glendale, Ariz.
  4. Visalia-Porterville, Calif.
  5. Hanford-Corcoran, Calif.
  6. Fresno-Madera, Calif.
  7. Pittsburgh-New Castle, Pa.
  8. Birmingham-Hoover-Cullman, Ala.
  9. Cincinnati-Middletown-Wilmington, Ohio-Ky.-Ind.
  10. Louisville-Jefferson County-Elizabethtown-Scottsburg, Ky.-Ind.; Modesto, Calif.

Resources

April 29, 2011 in Emissions | Permalink | Comments (3) | TrackBack

Petrobras moves up 10 spots to 8th largest publicly trade company in world

Petrobras, the Brazilian oil, gas and energy company, has become the world’s eighth-largest publicly traded company, according to a ranking prepared by Forbes magazine. In this edition of the ranking, the Company moved up ten positions compared to 2010, when it held the 18th place.

Petrobras ranked fifth in the profit and market value categories, and it is the only Latin American company to appear among the top 10. The ranking uses data such as profit, income, assets, and market value to assess the largest companies.

Also in 2011, Petrobras was rated the third biggest energy company in the PFC Energy 50 ranking based on market value, and rose from sixth to fourth place among the leading global companies operating in the industry in the ranking prepared by the Platts agency.

April 29, 2011 in Brief | Permalink | Comments (1) | TrackBack

April 28, 2011

Avjet Biotech negotiating strategic relationship with BioJet international for distributed refineries for drop-in renewable aviation fuel

Avjet Biotech, Inc. (ABI), a developer of small distributive refining systems in the 10 to 15 million gallon per year range and parent company of drop-in biofuel company Red Wolf Refining (RWR), is in negotiation for a strategic relationship with BioJet International Ltd, an international supply chain integrator, for renewable (bio) jet fuel and related co-products.

Under the agreement with ABI, BioJet will use the patented RWR System (earlier post) to build refineries that will produce drop-in renewable aviation biofuels from native feedstocks at locations around the globe.

BioJet International operates across the supply chain by owning or controlling large quantities of bio-feedstock, developing refining capacity, solving aviation fuel supply logistics, and handling sales to end users. It is also the first Alternative Fuels Strategic Partner of the International Air Transport Association.

ABI recently completed a license agreement to commercialize all patents and intellectual property related to the Professor William Roberts’ biofuels program at North Carolina State University, including products for the pharmaceutical and fine chemical industries from genetically modified marine microalgae. The license agreement is global in scope and extends to 22 foreign countries where patents have been filed.

In 2009, the National Science Foundation awarded the NC State team a $2-million grant to develop and scale up a unique, multi-step catalytic process to convert a wide range of fats, oils, and lipids produced by algae into transportation fuels that are chemically and physically similar to their petroleum counterparts. (Earlier post.)

The RWR System uses a thermal catalytic process to convert triglycerides contained in fats and oils into aviation biofuels in a three step process comprising hydrolysis, deoxygenation and hydrocarbon reforming. Unlike large refinery-scale systems such as those using Honeywell’s UOP’s Ecofining technology, or Neste’s NExBTL, the Red Wolf system is under development as a small, distributed refining system designed to be located close to feedstocks, says Martin Oliver, President and Director of Red Wolf Refining.

While we’re fairly comfortable with our economic model and pricing structure against anyone, we don’t want to consider ourselves in competition [with UOP]. A main differentiator is that we’re building refineries on a much smaller scale and one of the reasons we can do so is that we are not as [external] hydrogen intensive.

—Martin Oliver

RWR uses high-pressure, high temperature steam to separate free fatty acids from glycerol in the triglycerides in the feedstock. Water from the steam can be reused, and the glycerol byproduct can be burned to produce a power source for the process.

The free fatty acids resulting from hydrolysis and solvent are heated, pressurized, and passed through a catalyst in a reactor to produce n-alkanes, the building blocks of fuels. These are then reformed into branched alkanes and ring structures. The alkanes can be reformed differently to create a variety of fuel types. Red Wolf is focused on aviation fuels, Oliver said: JP5, JP8, and commercial.

The RWR System is under development for sale as a small distributive refining system to global entities or foreign governments that aspire to produce renewable aviation biofuels from native feedstocks. Red Wolf says it has been approached by global corporations and foreign governments for sub-licenses for its RWR System.

The company is currently focusing on camelina and jatropha as feedstocks as it continues to work with algae, Oliver said.

Another of our differentiators is that we can go out today and utilize whatever feedstock is available and the most abundant. We’re hoping that algae becomes available sooner than later. The fact that we have identified the [algae] strain puts us ahead of the game.

—Martin Oliver

ABI’s other division is Pinehurst Biologics, which produces patented enzymes and algal oil for aviation biofuel feedstock.

April 28, 2011 in Aviation, Bio-hydrocarbons, Fuels | Permalink | Comments (2) | TrackBack

UC Davis ITS researchers take a detailed look at water consumption and withdrawal requirements for ethanol

Mishra
Water consumption intensity of ethanol from corn grain and crop residue and the avoided/displaced water use credits assigned to coproducts: DGS and electricity. Credit ACS, Mishra and Yeh. Click to enlarge.

While a number of studies have tired to assess the water consumption required for ethanol production, the results differ by orders of magnitude, with estimates ranging from 1.1 to 335 L/vehicle kilometer traveled (VKT) for Iowa and from 59 to 214 L/VKT for Nebraska.

The major difference between these studies stems from the debate existing in the water life cycle analysis (LCA) literature regarding whether, and how, to include consumption of green water (GW), which comes from precipitation before and during the crop season and is stored as soil moisture, note UC Davis Institute of Transportation Studies (ITS) Gouri Shankar Mishra and Sonia Yeh in a new paper published in the ACS journal Environmental Science & Technology.

In their paper, Mishra and Yeh analyze the lifecycle water requirement consumption and withdrawal requirements of ethanol produced from corn and from crop residue.

To address the controversy regarding GW use, this study explicitly states the sources of water inputs (GW versus BW [blue water, i.e., surface water and groundwater] and surface water versus groundwater). Our water accounting system also considers different types of uses (consumptive, nonconsumptive, and withdrawal) and accounts for application losses, conveyance losses, water use of direct energy inputs throughout the life cycle, and coproduct credits.

—Mishra and Yeh

Comparison with fossil fuels
Water is required for crude oil recovery by water flooding, enhanced oil recovery via steam injection, and steam extraction of bitumen from oil sands and during refining of crude oil to produce gasoline.
BW consumption intensities of gasoline from conventional crude oil and Canadian oil sands range from 0.41 to 0.78 and from 0.29 to 0.62 L/VKT, respectively. A recent GAO report suggests the water intensity of gasoline from large oil shale deposits in the western United States could range from 0.29 to 1.01 L/VKT.
Assessing the differences in water impacts of biofuels and fossil fuels is more complicated than simply comparing the total water intensities, Mishra and Yeh note. The BW consumption of biofuels from rain-fed crops and residue is lower than that of gasoline, but orders of magnitude higher for those from irrigated crops.
Though the water intensity of fossil fuels is on average low compared with that of biofuels, oil sand production and shale oil development could result in substantial streamwater withdrawals and significant alteration of water flows during critical low river flow periods, groundwater depletion and contamination, and wastewater discharges.

Mishra and Yeh’s estimates of corn grain ethanol’s BW and GW consumption are lower than those of previous studies, due to the accounting of coproduct credits for water use, which they estimated to be 5% and 45% of the total BW used to produce ethanol from rain-fed and irrigated corn, respectively, and around 50% of GW in both cases.

They found that corn ethanol consumes 50-146 L/vehicle kilometer traveled (VKT) of BW and 1-60 L/VKT of GW for irrigated corn and 0.6 L/VKT of BW and 70-137 L/VKT of GW for rain-fed corn after coproduct credits. Extending the system boundary to consider application and conveyance losses and the water requirements of embodied energy increases the total BW withdrawal from 23% to 38% and BW + GW consumption from 5% to 16%.

They estimated that, in 2009, 15-19% of irrigation water was used to produce the corn required for ethanol in Kansas and Nebraska without coproduct credits and 8-10% after credits. Harvesting and converting the cob to ethanol reduces both the BW and GW intensities by 13%.

The BW and GW requirements of ethanol from corn grown in different regions provide useful information for local water resource management; for example, water use by ethanol can be compared with a region’s total water budget to identify potential water availability constraints and risks. However, such volumetric estimates do not consider differences in ecosystem or socioeconomic trade-offs as a result of differences in local hydrological conditions—specifically water “scarcity”.

Our method necessarily employs spatial and temporal aggregation. It sums across types of water consumption (BW and GW consumption and avoided water credits) in locations where the relative importance of water-related aspects may differ; thus, some results may carry no clear indication of potential social and/or environmental harm or trade-offs. Similarly, temporal aggregation of water use estimates ignores the interseasonal variability of water use and water scarcity and can therefore yield erroneous conclusions concerning seasonal water use competition.

Recent literature on freshwater LCA has developed regionally differentiated characterization factors that measure water scarcity at a watershed level and also account for temporal variability in water availability. Volumetric estimates of GW and BW may be converted using characterization factors to provide “stress-weighted” or “ecosystem-equivalent” water footprint estimates that can be compared across regions. Work is ongoing to use the explicit water inventory results to undertake impact analysis and accurately assess the effects of biofuel production on water resources.

—Mishra and Yeh

Resources

  • Gouri Shankar Mishra and Sonia Yeh (2011) Life Cycle Water Consumption and Withdrawal Requirements of Ethanol from Corn Grain and Residues. Environmental Science & Technology Article ASAP doi: 10.1021/es104145m

April 28, 2011 in Ethanol, Water | Permalink | Comments (30) | TrackBack

Altech-Eco receives final EPA certification for dedicated CNG conversions systems for Ford E-Series

Altech-Eco Corporation has obtained a Certificate of Conformity (COC) from the EPA for their dedicated 2011 Ford E-Series 5.4L compressed natural gas (CNG) conversion system. The dedicated system runs entirely on natural gas.

Altech-Eco’s CNG E-Series conversion system converts the E-150, E-250 & E-350 vans; the system is complete and includes manufacturer-rated CNG cylinders with fuel storage capacity starting at of 21.2 GGE (Gas Gallon Equivalent) and an extended option of 31.6 GGE, with a driving range of 240 - 480 miles (386 to 773 miles) depending on fuel tank size.

The CNG conversion system for the 2011 Ford E-Series is now available at select participating Ford dealerships and approved aftermarket conversion facilities, or by contacting Altech-Eco directly.

April 28, 2011 in Brief | Permalink | Comments (1) | TrackBack

Ceria in platelet form stores more oxygen than nanocrystalline form

Ceria is an important catalyst, primarily used in oxidation reactions because of its outstanding ability to store oxygen and release it. Now, Christopher B. Murray and a team at the University of Pennsylvania have developed a simple synthetic technique to produce ceria in the form of 2D nanoplates. As the researchers report in the journal Angewandte Chemie, these have proven to be better at storing oxygen than conventional three-dimensional nanoparticles.

Ceria
TEM images of a) square ceria nanoplates, c) stacking square ceria nanoplates. Credit: Wang et al. Click to enlarge.

In automotive catalytic converters, ceria helps to level out hydrocarbon spikes. It can also be used in the removal of soot from diesel exhaust and organic compounds from wastewater, for example. In fuel cells, ceria is used as a solid electrolyte. Cerium, a rare-earth metal, can easily switch between two different oxidation states (+IV and +III), so it undergoes a smooth transition between CeO2 and materials with a lower oxygen content. This makes ceria an ideal material for oxygen storage.

Ceria can be produced as a nanomaterial in various different forms; almost all of the previously described forms were three-dimensional.

Murray’s team’s synthetic technique for two-dimensional ceria nanoplates is based on the thermal decomposition of cerium acetate at 320 to 330 °C. Critical to their success is the presence of a mineralization agent, which speeds up the crystallization process and controls the morphology. Depending on the reaction conditions, the researchers obtained either roughly square plates with a thickness of 2 nm and edges about 12 nm in length, or elongated plates with dimensions of about 14 x 152 nm.

To test the oxygen storage capacities of the various forms of ceria, the researchers established a very simple thermogravimetric test: They alternately exposed the samples to oxygen and hydrogen and recorded the change in mass due to oxygen absorption/emission. The nanoplates proved to be superior to the conventional particulate systems and displayed an oxygen capacity three to four times as high as that of conventional three-dimensional nanoparticles.

The plates do have a higher surface-to-volume ratio than the three-dimensional particles but the uptake of oxygen in the body of the nanoplates is required to explain this magnitude of enhancement. Furthermore, not all surfaces of a ceria crystal are equally good for the absorption and emission of oxygen; the platelet surfaces were of the right type.

Resources

  • Dianyuan Wang, Yijin Kang, Vicky Doan-Nguyen, Jun Chen, Rainer Küngas, Noah L. Wieder, Kevin Bakhmutsky, Raymond J. Gorte, and Christopher B. Murray (2011) Synthesis and Oxygen Storage Capacity of Two-Dimensional Ceria Nanocrystals. Angew. Chem. Int. Ed. 50, 1 – 4 doi: 10.1002/anie.201101043

April 28, 2011 in Brief | Permalink | Comments (1) | TrackBack

Aeristech turbocharging technology to be showcased at Challenge Bibendum

Among the UK engineering innovations to be showcased by the LowCVP at the upcoming Challenge Bibendum in Berlin is the electromechanical turbocharging system being developed by Aeristech. (Earlier post.)

Aeristech Technology separates conventional turbochargers into their two key elements: generator and compressor. This allows independent control of the input and output elements of turbocharging.

Aeristech has developed extremely compact, electrically efficient (~98%), power dense (56kW), rapidly accelerating (up to 150,000 RPM in 0.5 seconds) high-speed motors and generators that materially enhance vehicle efficiency.

Applications include greater engine downsizing by utilizing a full electric turbocharger technology on internal combustion engines; reducing particulates emissions through enhancing combustion; recycling power more efficiently through turbo generation; and enhancing performance on hybrid vehicles.

Other organizations to be showcased by LowCVP at Challenge Bibendum are:

  • Ashwoods Automotive Limited, the UK’s largest supplier of hybrid commercial vehicles and a known provider of emission reduction technologies and components.

  • Coventry University, which works in a broad range of transport fields including automotive design, automotive engineering, ergonomics and automotive journalism. The University has an growing research portfolio in the areas of Low Carbon Vehicles and Integrated Transport & Logistics.

  • Oxford YASA Motors. The Yokeless And Segmented Armature (YASA) motor (earlier post) is a compact and lightweight axial-flux topology that has double the torque density of other market leading motors. At the heart of the YASA technology is an efficient axial flux motor that has a high torque-to-weight (up to 40 Nm/kg) and power-to-weight (up to 10 kW/kg) ratio.

  • Oxy-Gen Combustion. Oxy-Gen Combustion can deliver emissions and fuel savings through its enabling emissions pre-treatment system for HCCI and CAI combustion.

  • Zeta Automotive. Zeta’s EconoSpeed is an electronic control module sitting between the accelerator pedal and the engine’s ECU computer and can be fitted to any vehicle with an electronic throttle pedal. It limits a vehicle’s maximum rate of acceleration to simulate that of a partially laden vehicle, and by also limiting the maximum RPM and maximum road speed, it mimics the way an economical driver would drive.

April 28, 2011 in Brief | Permalink | Comments (1) | TrackBack

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