High Octane Fuels
[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Promising results from Mercedes-Benz fleet test of Clariant high-octane cellulosic E20
September 23, 2014
Clariant, Haltermann and Mercedes-Benz have fleet-tested high-octane sunliquid 20 fuel—containing 20% cellulosic ethanol produced from straw—since January. (Earlier post.) The test found that the use of sunliquid 20 improves engine efficiency—more than compensating for its 4% lower energy content compared to E10. For drivers, this means with sunliquid 20, CO2emissions are reduced while consumption remains the same.
Use of sunliquid 20 also resulted in a 50% improvement in particle emissions count in contrast to the EU 5 reference fuel. The cellulosic ethanol in sunliquid 20 demonstrates greenhouse gas emission savings of up to 95% across the entire value chain (well-to-wheel perspective) without competing with food production or agricultural acreage.
Study finds US refining sector could produce higher octane E20 and E30 at modest additional cost; enabling more efficient engines
September 18, 2014
|A new study concludes that using ethanol can be a cost-effective approach to increasing the octane rating of the US gasoline pool. Source: ACS, Hirshfeld et al. Click to enlarge.|
A number of studies recently have pointed out that increasing the octane rating of the US gasoline pool (currently ∼93 Research Octane Number (RON)) would enable higher engine efficiency for light-duty vehicles through reducing engine knock constraints, thereby enabling the design of new spark-ignition engines with higher compression ratios and boost levels. (Earlier post.) Such a move would also have significant implications for refineries in the US refining sector, whether the higher octane was achieved via more severe refining operations, increased use of ethanol, or both.
A linear programming analysis of US refining sector by a team from MathPro Inc., Ford, GM and Chrysler has found that, by increasing the volume of ethanol, the refining sector could produce hydrocarbon blendstocks for oxygenate blending (BOBs) yielding finished E20 and E30 gasolines with higher octane ratings at modest additional refining cost (ARC): e.g., ∼1¢/gal for 95-RON E20 or 97-RON E30; 3–5¢/gal for 95-RON E10, 98-RON E20, or 100-RON E30; and 96-RON E10, 99-RON E20, or 101-RON E30 gasoline pools at approximately 10¢/gal.
Cummins ETHOS 2.8L optimized E-85 engine demonstrates 50-80% reduction in CO2 emissions in medium-duty truck
July 14, 2014
|The ETHOS 2.8L demo truck. Click to enlarge.|
Cummins has developed an E-85-specific engine and powertrain that reduce carbon dioxide emissions by as much as 80% compared with a baseline gasoline-powered medium-duty truck. The work was jointly funded by Cummins and partners ($3,790,027) in partnership with the California Energy Commission (CEC) ($2,712,140).
The Cummins ETHOS 2.8L is designed specifically to use E-85 (85% ethanol and 15% gasoline). To take full advantage of the favorable combustion attributes and potential of E-85, the engine operates at diesel-like cylinder pressures and incorporates advanced spark-ignition technology. It delivers the power (up to 250 hp / 186 kW) and peak torque (up to 450 lb-ft / 610 N·m) of gasoline and diesel engines nearly twice its 2.8-liter displacement.
SwRI engineers win SAE award for paper on impact of octane and cooled EGR on engine performance and efficiency
July 03, 2014
A team of engineers from Southwest Research Institute (SwRI) has received the prestigious SAE International Harry L. Horning Memorial Award for a 2012 technical paper (2012-01-1149) investigating different octane-rated gasolines and exhaust gas recirculation (EGR) levels.
Institute Engineer Dr. Charles Roberts, Assistant Director Dr. Terry Alger and Research Technologist Barrett Mangold, all of SwRI’s Engine, Emissions and Vehicle Research Division, received the award at the SAE World Congress in Detroit in April. Former SwRI employee Jess Gingrich is also a co-recipient.
LowCVP reports indicate pathways for meeting renewable energy targets in transportation, decarbonizing fuel to 2030 and beyond
June 18, 2014
|Illustrative impact of the fuel roadmap. Source: LowCVP, Element Energy. Click to enlarge.|
The UK’s LowCVP has published twin reports which set out how the UK could meet its 2020 targets defined in the EU’s Renewable Energy Directive, and proceed on a pathway to decarbonize road transport fuel in the period to 2030 and beyond.
The LowCVP—the stakeholder body which brings government, industry and other stakeholders together to focus on the challenges of decarbonizing road transport—commissioned energy consultancy Element Energy to analyze the UK’s options for meeting the Renewable Energy Directive’s (RED) 2020 transport target which states that at least 10% of the final energy consumption in transport must come from renewable sources. This and the parallel Fuels Roadmap report benefitted from wide industry consultation and explicitly set out to align with existing powertrain roadmaps (including those published by the Automotive Council and the LowCVP).
Ohio State team wins EcoCAR2 competition with E85 series-parallel plug-in hybrid Malibu
June 13, 2014
|OSU’s series-parallel PHEV. Click to enlarge.|
The US Department of Energy and General Motors Co. announced that the Ohio State University (OSU) team was the overall winner of the EcoCAR 2: Plugging In to the Future finals. The OSU team’s engineered 2013 Chevrolet Malibu featured a series-parallel plug-in hybrid drive with E85-fueled engine technology.
The OSU EcoCar2 Malibu featured an A123 18.9 kWh battery pack used with an 80 kW peak electric machine on the rear axle to provide power to the rear wheels through a single-speed gearbox. The vehicle’s front powertrain utilized a 1.8 L, high-compression-ratio engine recalibrated to run on E85 fuel and an 80 kW peak electric machine to provide power to the front wheels through a six-speed automated manual transmission. The vehicle is capable of operating in charge-depleting, charge-sustaining series and charge-sustaining parallel modes.
MIT study finds significant economic and environmental benefits from designing US LDVs to use higher octane gasoline (98 RON)
May 29, 2014
In a companion study to an SAE paper presented in April (earlier post), researchers at MIT have quantified the net economic and CO2 emissions benefit that could be obtained by utilizing 98 RON gasoline in light-duty vehicles, based on reasonable assumptions for possible refinery changes and the evolution of the LDV fleet. The paper, they note, is the first modern, peer-reviewed publication to address the costs and benefits of introducing higher octane gasoline.
According to the analysis, published in the ACS journal Environmental Science & Technology, greater use of 98 RON gasoline in appropriately tuned vehicles could further reduce annual gasoline consumption in the US by 3.0–4.4%. Even accounting for the increase in refinery emissions from production of additional high-RON gasoline, net CO2 emissions are reduced by 19–35 Mt/y in 2040 (2.5–4.7% of total direct LDV CO2 emissions). The MIT team estimated the annual direct economic benefit to be $0.4–6.4 billion in 2040, and the annual net societal benefit—including the social cost of carbon—to be $1.7–8.8 billion in 2040.
Study finds alcohol mix from biomass-derived syngas could be suitable replacement for ethanol in fuel blending
May 12, 2014
|AlcoMix displays antiknock blending characteristics similar to those of ethanol when blended at various concentrations with non-oxygenated gasoline (RON = 82). Credit: ACS, Rapp et al. Click to enlarge.|
Results of a study by a team from the US and Austria suggest that the primary alcohol mixture (“AlcoMix,” comprising 75% ethanol, 11% 1-propanol, 8% 1-butanol, and 6% 1-pentanol) produced from biomass-based syngas could be used as a substitute for ethanol as a primary fuel or as an antiknock blending component.
The purpose of the study, reported in the ACS journal Energy & Fuels, was to determine whether AlcoMix,the probable outcome of the thermochemical conversion of biomass using Fischer–Tropsch chemistry with synthesis gas, might be a suitable replacement for ethanol in fuel blending as an antiknock blending component for spark-ignited engines.
MIT study: higher octane standard fuel in US could lower fleet fuel consumption & GHG an extra 4.5-6% by 2040
April 24, 2014
Offering a higher-octane gasoline to the consumer market in the US as the standard grade could deliver an incremental 4.5% to 6% reduction in fleet fuel consumption and greenhouse gas emissions by 2040, on top of a projected 26.8% reduction by then in the baseline case (i.e., without higher octane fuel, but with other projected vehicle and powertrain technology improvements), according to a new analysis by a team at MIT. For their paper, the team proposed a 98 RON gasoline—currently the US premium grade—as the new standard fuel. In other words, they proposed making the current premium fuel the new standard grade.
The analysis by Eric Chow, John Heywood and Raymond Speth, presented as a paper at the recent SAE 2014 World Congress, seeks to quantify the reductions in consumption and GHG if new vehicles designed to use the higher-octane fuel were deployed. Raising octane reduces engine knock constraints, enabling the design of new spark-ignition engines with higher compression ratios and boost levels. This leads to improved engine efficiencies and the sought reductions. (Earlier post.)
ExxonMobil, Corning and Toyota develop onboard membrane system to separate gasoline into octane fractions to optimize engine efficiency and performance
April 10, 2014
ExxonMobil, Corning and Toyota have collaborated to develop an Onboard Separation System (OBS) to optimize gasoline engine efficiency and performance. OBS is a membrane-based process that separates gasoline into higher and lower octane fractions—essentially creating a dual fuel system from a single base fuel—allowing optimal use of fuel components based on engine requirements. The system, say the researchers, offers the potential to exploit most of the benefits of operating on premium high octane fuel while using less expensive regular grade more effectively.
In a paper on the OBS presented at the SAE 2014 World Congress, the researchers suggested that potential applications include downsizing to increase fuel economy by ∼10% while maintaining performance, and or using OBS with turbocharging to improve performance and knock resistance.
Study finds butanol-gasoline blends effective to control soot from CI engines under Low Temperature Combustion
January 31, 2014
|(Left) Thermal efficiency and (right) soot from different gasoline-butanol blends at different EGR rates. Yang et al. Click to enlarge.|
A study by a team at Tianjin University found that the addition of n-butanol to gasoline for use in a compression ignition engine (CI) under Low Temperature Combustion (LTC) conditions has a significant effect on soot reduction. The peak soot value of a 30% butanol blend (B30) was 85% lower than that of pure gasoline; the EGR rate that corresponds to the peak value of soot is also decreased with the higher n-butanol fraction. Their study is published in the journal Fuel.
Partially Premixed Combustion involving the injection of gasoline fuel into CI engines is being explored by other researchers as a means to reducing simultaneously NOxand soot emissions. High octane fuels such as gasoline are preferred for high-efficiency and clean combustion at high engine loads, the Tianjin researchers note.
Global Bioenergies to collaborate with Audi on development of drop-in bio-isooctane
January 21, 2014
Global Bioenergies (GBE), a leading developer of one-step fermentation processes for the direct and cost-efficient transformation of renewable resources into light olefins (earlier post), has signed a collaboration agreement with Audi on the development of bio-isooctane—a high-performance drop-in biofuel for gasoline engines—derived from bio-isobutene. In 2011, GBE had announced an agreement “with a major German car manufacturer” regarding an undisclosed application of GEB’s technology. (Earlier post.)
Under the agreement, GBE will supply Audi with isooctane derived from isobutene produced at its new pre-commercial pilot system at the Fraunhofer CBP in Leuna. (Earlier post.) During the two-year collaboration, this agreement also foresees the possibility for Audi to acquire shares of Global Bioenergies corresponding to less than 2% of its capital.
Oak Ridge Lab study finds E30 blend and EGR can deliver significant efficiency improvements in optimized SI engines
January 17, 2014
Researchers at Oak Ridge National Laboratory’s National Transportation Research Center (NTRC) report that an E30 (30% ethanol) mid-level ethanol blend shows promise as a means for significant improvement in vehicle efficiency in optimized spark-ignited (SI) engines. Results of the study by Derek Splitter and Jim Szybist suggest that it could be possible to implement a 40% downsize + downspeed configuration (1.2 L engine) into a representative midsize sedan using this combination of optimized engine and mid-level alcohol blend.
As an example, for a midsize sedan at a 65 mph (105 km/h) cruise, estimated fuel efficiency of 43.9 mpg (5.4 l/100 km) with engine-out CO2 of 102 g/km could be achieved with similar reserve power to a 2.0 L engine fueled with regular gasoline (38.6 mpg/6.1 l/100km, engine out CO2 of 135 g/km). The data suggest that, with midlevel alcohol–gasoline blends, engine and vehicle optimization can offset the reduced fuel energy content of alcohol–gasoline blends and likely reduce vehicle fuel consumption and tailpipe CO2 emissions.
Researchers explore ethanol-diesel dual-fuel combustion for reduction in engine-out emissions
November 14, 2013
|Effect of ethanol energy fraction and PFI position on CO, NOx, HC, and opacity emissions. Credit: ACS, Padala et al. Click to enlarge.|
Researchers at the University of New South Wales (Australia) have demonstrated the potential for ethanol use in diesel engines with dual-fuel combustion, in which ethanol is injected into the intake manifold and diesel is directly injected into the engine cylinder. A paper on their work is published in the ACS journal Energy & Fuels.
The goal of such an approach is effectively to address some of the drawbacks of conventional diesel combustion, such as higher in-cylinder soot formation associated with locally rich mixtures and high flame temperatures and engine-out emissions of NOx.
Omnitek selects DD 12.7L Series 60 and Cat C15 engine models for diesel-to-gas conversion project at Port of Seattle
November 04, 2013
Omnitek Engineering Corporation has selected the 12.7 L Detroit Diesel Series 60 and the Caterpillar C15 engine models for the beginning of the second phase of a Puget Sound Clean Air Agency pilot project, which includes the development of diesel-to-natural gas engine conversion kits for these engine models and obtaining Environmental Protection Agency (EPA) approval.
Omnitek’s diesel-to-natural gas engine conversion system was selected as the best technology under the competitive grant process for the agency’s “Piloting Engine Upgrade Technologies in the Freight Mobility Sector” project. (Earlier post.)