High Cetane Fuel Combustion Performance in a Conventional Military Diesel Engine

Cowart, Jim S.; Carr, Matthew A.; Caton, Patrick; Stoulig, Lars; Prak, Dianne J. Luning; Moore, Andrew J.; Hamilton, Len

doi:10.4271/2011-01-0334

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…Measurements of the fuels’ physical properties followed procedures employed in previous studies. ,,,,,,,,− Briefly, speed of sound, density, viscosity, surface tension, and flash point were measured using Density and Sound Analyzer (Anton Parr DSA 5000), Stabinger Viscometer (Anton Parr SVM 3000), Axisymmetric drop shape analyzer (Kruss DS100), and Setaflash Series 8 flash point tester (Stanhope-Seta Model 82000–0, closed-cup). The calibration of each instrument and their accuracy determination was accomplished using NIST-traceable and certified standards as previously described. , The DS100 calculates surface tension by fitting the Young–LaPlace equation to an image of a droplet formed within the magnification window using air and drop density.…”

Section: Methodsmentioning

confidence: 99%

Formulation of Surrogate Fuel Mixtures Based on Physical and Chemical Analysis of Hydrodepolymerized Cellulosic Diesel Fuel

et al. 2016

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Surrogate fuel mixtures for a hydrodepolymerized cellulosic diesel (HDCD) fuel were formulated based on HDCD's physical properties and chemical composition. HDCD was found to contain alicylic, cyclic, and aromatic compounds. Surrogate mixtures composed of trans-decahydronaphthalene (trans-decalin) and 1,2,3,4-tetrahydronaphthalene (tetralin) matched HDCD's speed of sound, density, and bulk modulus. Diesel engine experiments were conducted on mixtures containing petroleum diesel fuel (60 and 80% volume fraction) mixed with HDCD, tetralin, trans-decalin, or a mixture with 0.42 mass fraction of tetralin in trans-decalin. At both volume fractions, the start-up performance of the two-component surrogate/ petroleum fuel mixtures matched that of HDCD/petroleum mixtures. The trans-decalin/petroleum fuel mixtures started faster while the tetralin/petroleum fuel mixtures started more slowly than those containing HDCD. These results show that speed of sound, density, and bulk modulus can be used as metrics to design surrogate fuel mixtures that match fuel start-up performance in diesel engines.

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Section: Methodsmentioning

confidence: 99%

Formulation of Surrogate Fuel Mixtures Based on Physical and Chemical Analysis of Hydrodepolymerized Cellulosic Diesel Fuel

et al. 2016

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“…However, this study was done using an indirect injection diesel engine that may be uncharacteristic for typical diesel engines, which utilize direct injection. 10 Olree and Lenane tested fuels with cetane numbers ranging from 35 to 55, and observed that shorter IGD led to less fuel-air premixing and lower rates of maximum pressure rise. 11 Another study compared the IGDs of 20 pure component fuels with a very wide range of cetane numbers (from negative values to 100), but again using a single-cylinder indirect injection research diesel engine, which may not be representative of most production diesel engines.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In one study, Cowart et al investigated a series of alternative fuels and pure component fuels spanning a cetane number range from 44 (military F-76 petroleum diesel) to 100 ( n -hexadecane), noting in particular the effects of fuel reactivity and density on IGD and other performance metrics, but finding overall satisfactory performance. However, this study was done using an indirect injection diesel engine that may be uncharacteristic for typical diesel engines, which utilize direct injection . Olree and Lenane tested fuels with cetane numbers ranging from 35 to 55, and observed that shorter IGD led to less fuel-air premixing and lower rates of maximum pressure rise .…”

Section: Introductionmentioning

confidence: 99%

Combustion Characterization and Ignition Delay Modeling of Low- and High-Cetane Alternative Diesel Fuels in a Marine Diesel Engine

et al. 2014

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ABSTRACT:In support of an ongoing U.S. Navy alternative fuel evaluation program, the combustion characteristics of two very different alternative diesel fuels were evaluated in a direct-injection marine diesel engine across a variety of speeds and loads. The fuels were an algal-based hydrotreated renewable diesel fuel (HRD) with cetane number of ∼75 and a synthetic paraffinic kerosene (SPK) with cetane number of ∼25. These fuels were experimentally tested as blends with conventional petroleumbased military diesel fuel (designated F-76) with cetane ≈ 46, giving a cetane number range from 25 to 75. Start of injection (SOI) was characterized using a strain gauge to determine actuation of the mechanical unit injector; SOI remained essentially unchanged for changes in fuel type. As expected based on cetane number, ignition delay (IGD) increased with greater amounts of SPK fuel and decreased for greater amounts of HRD fuel in the test blend. Energy release analysis showed that longer IGD led consistently to slightly advanced combustion phasing, as indicated by the location of 50% mass fraction burned, decreased overall combustion duration, and greater maximum rate of pressure rise due to greater fuel-air premixing. Fuel consumption was 0−5% higher for these alternative fuels. Ignition delay was modeled using a detailed primary reference fuel mechanism tuned to match the measured cetane number of each neat and blended fuel. The modeled chemistry was able to capture relative changes in the experimentally observed IGD, suggesting that the measured differences in physical properties, which will affect spray development, do not contribute as significantly to differences in IGD. The results suggest that typical higher cetane alternative fuels, such as HRD, have no deleterious effects from the perspective of combustion characteristics. Processes that yield lower cetane alternative fuels, such as SPK, while still achieving satisfactory performance, begin to show signs of problems through delayed combustion, increased rates of pressure rise, and higher peak pressures, which induce higher mechanical stress and combustion noise. ■ INTRODUCTIONDeveloping viable future alternatives to petroleum-based fuels is of continued high importance for civilian and military prime movers. From a military perspective, the Department of Defense is the single largest consumer of energy in the U.S., using approximately two percent of the U.S. petroleum demand.1 In 2009, the U.S. Navy outlined the several important energy goals, including an alternative-fueled carrier strike group (2016) and a 50% alternative-fuel energy portfolio by 2020. 2Given the prevalence and longevity of diesel engines in service, widespread redesign or replacement to accommodate possible future variations in fuels is unlikely. Future fuels will therefore need to be compatible with present technology. Understanding how future fuels will perform in current and legacy technology diesel engines is important for qualification and acceptance of candidate fuels. However, there is...

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“…The surface tension of the ATJ and surrogate mixtures was measured via a Kruss Model DS100 axisymmetric drop shape analyzer using procedures reported in previous work. ,,,,− Briefly, a liquid droplet of the each sample is formed at the tip of a needle in air. An image of the droplet is taken, enlarged, and fit with the Young–LaPlace equation, using input of the densities of the organic phase and air and the diameter of the needle, which was measured using a micrometer.…”

Section: Methodsmentioning

confidence: 99%

Physical and Chemical Analysis of Alcohol-to-Jet (ATJ) Fuel and Development of Surrogate Fuel Mixtures

et al. 2015

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In this study, the chemical composition and physical properties of an alcohol-to-jet (ATJ) fuel were used to develop a surrogate mixture containing commercially available hydrocarbons. Analysis of the chemical composition of the ATJ showed a high quantity of two specific branched alkanes (2,2,4,4,6,8,8-heptamethylnonane and 2,2,4,6,6-pentamethylheptane) and a small quantity of other branched alkanes that are isomers of these two alkanes. Surrogate mixtures containing 2,2,4,4,6,8,8-heptamethylnonane and a mixture of isododecane isomers were prepared to determine what composition would match the density, viscosity, speed of sound, bulk modulus, surface tension, and flash point of ATJ. The optimal surrogate contained a 0.25 mass fraction of 2,2,4,4,6,8,8-heptamethylnonane in isododecane isomers. Combustion experiments were then conducted in a Yanmar diesel engine with fuel mixtures containing 70% (by volume) petroleum jet fuel with 30% ATJ, 2,2,4,4,6,8,8-heptamethylnonane, the optimal surrogate mixtures based on physical properties, or the isododecane isomers. The startup performances of the three 30% surrogate mixtures were very similar to that of the 70% JP-5 with 30% ATJ fuel. No significant differences were seen in the engine combustion characteristics of the three 70/30 surrogates, as compared to the base 70% JP-5/ 30% ATJ fuel mixture. These results show that a surrogate mixture has been successfully prepared that matches the physical and chemical properties and combustion behavior of an ATJ fuel.

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High Cetane Fuel Combustion Performance in a Conventional Military Diesel Engine

Cited by 6 publications

References 7 publications

Formulation of Surrogate Fuel Mixtures Based on Physical and Chemical Analysis of Hydrodepolymerized Cellulosic Diesel Fuel

Formulation of Surrogate Fuel Mixtures Based on Physical and Chemical Analysis of Hydrodepolymerized Cellulosic Diesel Fuel

Combustion Characterization and Ignition Delay Modeling of Low- and High-Cetane Alternative Diesel Fuels in a Marine Diesel Engine

Physical and Chemical Analysis of Alcohol-to-Jet (ATJ) Fuel and Development of Surrogate Fuel Mixtures

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