High Octane Fuels
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EIA: trends in downsized engine design leading to increased demand for higher-octane gasoline
April 06, 2016
Since 2013, the share of premium gasoline in total motor gasoline sales in the US has steadily increased to 11.3% in August and September 2015—the highest share in more than a decade, according to data from the US Energy Information Administration (EIA).
This trend of increasing demand for higher octane gasoline is likely driven by changes in fuel requirements for light-duty vehicles (LDV) in response to increasing fuel economy standards, which will have widespread implications for future gasoline markets, according to EIA analysts.
Diesel/2-methylfuran blends show higher brake thermal efficiency, higher NOx than diesel
February 22, 2016
Researchers at Wuhan University report on the first comprehensive study of the combustion and emissions performance of blends of diesel and the renewable fuel 2-methylfuran (MF) in compression-ignition engines. Their paper is published in the journal Fuel.
Among their findings were that diesel–MF blends show higher brake thermal efficiency (BTE) than pure diesel. However, diesel–MF blends also lead to higher NOx emissions than pure diesel and the NOx emissions are increased with the increase of MF fraction.
Primus Green Energy produces 100-octane gasoline at commercial demonstration gas-to-liquids plant; improvement to STG+ technology
February 02, 2016
Primus Green Energy Inc., a gas-to-liquids (GTL) technology and solutions company that transforms methane and other hydrocarbon gases into gasoline and methanol (earlier post), has successfully produced 100-octane gasoline at its commercial demonstration plant in Hillsborough, New Jersey.
Primus achieved this milestone as a result of an improvement to its proprietary STG+ technology—itself essentially an improvement upon commercial methanol synthesis processes and ExxonMobil’s methanol-to-gasoline (MTG) process—which allows its plant to produce high-octane gasoline in addition to RBOB (“Reformulated Gasoline Blendstock for Oxygenate Blending”) gasoline and methanol.
Westport and GTI awarded $900,000 to advance natural gas combustion technology; ESI with high frequency corona discharge ignition
December 09, 2015
Westport Innovations Inc., together with the Gas Technology Institute (GTI), has been awarded US$900,000 towards a program to advance state-of-the-art natural gas combustion technology. The work will feature Westport’s enhanced spark ignited (ESI) natural gas engine technology (earlier post) with the integration and demonstration of high frequency corona discharge ignition on an original equipment manufacturer (OEM) partner’s engine. The engine has a displacement of between 1 and 1.5 liters per cylinder and is targeted at medium-duty commercial vehicle applications.
Using 100% dedicated natural gas as fuel, Westport’s ESI technology optimizes the combustion and thermal efficiencies of the engine by taking full advantage of the ultra-high octane performance fuel properties of natural gas. The technology enables a “downsized” natural gas solution that is cost-competitive while providing similar levels of power, torque, and fuel economy to a larger diesel engine.
TMFB researchers investigate engine performance of two possible future tailor-made biofuels
November 30, 2015
Researchers at RWTH Aachen University in Germany report on their evaluation of two possible future biofuels—tailor-made from biomass—in a paper in the journal Fuel. The team investigated the use of 2-butanone (also referred to as methyl ethyl ketone, MEK) and 2-methylfuran, both of which had been identified within the Cluster of Excellence “Tailor-Made Fuels from Biomass” (TMFB) (earlier post).
Investigations of the fuels’ autoignition tendency were carried out on a rapid compression machine (RCM); thermodynamic investigations were conducted on a direct injection spark ignition single cylinder research engine.
Team from GM, Ford, FCA reviews how to calculate engine efficiency benefits of high octane fuels
August 25, 2015
A team of engineers from GM Powertrain, Ford and FCA have published a detailed review of how to estimate the engine efficiency benefits of higher octane fuel—e.g., fuel with higher ethanol content—for part- and full-load operation for different engine types and fuel assumptions. Their paper is published in the ACS journal Environmental Science & Technology.
Engine compression ratio plays a fundamental role in engine efficiency; a higher compression ratio improves efficiency, but also causes higher temperatures and pressures of the unburned air-fuel mixture which can lead to knock at high loads. Compression ratio is thus limited to avoid knock. The compression ratio selected for a particular engine depends, the authors note, on the expected duty cycle and fuel octane. A higher compression ratio can be used if an engine will operate primarily at light loads, such that degraded efficiency at high loads is more than offset by improved efficiency at light loads.
UC Riverside team characterizes impact on PM of fuels with varying aromatics and octane rating; benefit of increased ethanol fraction
August 18, 2015
Researchers at the University of California-Riverside have characterized the effect of decreased aromatic content fuels combusted in advanced vehicle technologies on emissions of particulate matter (PM). In a paper in the ACS journal Environmental Science & Technology, they present the changes in PM emissions for different fuels, engine technologies, and operating conditions. Among their findings is that an increased ethanol fraction in gasoline could help reduce PM mass and black carbon (BC) from gasoline direct injection engines (GDI).
Typical commercial gasoline comprises varying concentrations of aromatic hydrocarbons and octane ratings; the impacts on PM such as black carbon (BC) and water-soluble and insoluble particle compositions of these differences are not well-defined. The UC Riverside study tested seven 2012 model year vehicles, including one port fuel injection (PFI) configured hybrid vehicle; one PFI vehicle; and six GDI vehicles.
Tsinghua studies on alcohol-gasoline dual fuel engines show fuel efficiency and particle number benefits
August 10, 2015
Researchers at Tsinghua University in China are studying the effects of Dual-Fuel Spark Ignition (DFSI) combustion fueled with different alcohols and gasoline. In one paper, published in the journal Fuel, they investigated the use of alcohols–gasoline DFSI Combustion for knock suppression and high fuel efficiency using a gasoline engine with high compression ratio.
In a second paper, also published in Fuel, they systematically compared the stoichiometric alcohol–gasoline and gasoline–alcohol DFSI combustion for engine particle number (PN) reduction (and fuel economy improvement), also using a high compression ratio gasoline engine.
NREL examines potential of blending ethanol with condensate for flex-fuels and high-octane mid-level blends
July 21, 2015
A team at the National Renewable Energy Laboratory (NREL), with a colleague at EcoEngineering, has explored the potential of blending ethanol with natural gasoline (condensate) to produce flex-fuels (ASTM D5798-13a) and high-octane, mid-level ethanol blends (MLEBs). A paper on their work is published in the ACS journal Energy & Fuels.
The study addresses two current market conditions: first, more ethanol is produced domestically than can legally be blended in E10 (the ethanol blend wall). Second, as a result of recent increases in crude oil and natural gas production in the US, condensate—a component of natural gas liquids (NGLs) found in rich gas—is produced in abundance and could potentially serve as a lower-cost blendstock. Current US production of condensate is estimated at 1.5 × 108 m3 annually compared to 9.7 × 107 m3 annually 10 years ago.
Argonne, Ford and FCA partnering to study natural gas and gasoline blending for 50% cut in gasoline, 10% boost in efficiency and power density
July 14, 2015
Researchers at the US Department of Energy’s (DOE) Argonne National Laboratory are partnering with Ford Motor Company and FCA US LLC in pre-competitive research to study blending natural gas and gasoline using natural gas direct injection to enable more efficient engines. The project is a cooperative research and development agreement (CRADA) resulting from the 2014 DOE Vehicle Technologies Office (VTO) Funding Opportunity Announcement (FOA).
The project’s objective is to understand potential benefits and demonstrate targeted blending of gasoline and natural gas in an engine that uses half as much gasoline and shows a 10% increase in overall efficiency and a 10% improvement in power density.