POMDME-diesel blends: Evaluation of performance and exhaust emissions in a single cylinder heavy-duty diesel engine

Iannuzzi, Stefano; Barro, Christophe; Boulouchos, Konstantinos; Burger, J.

doi:10.1016/j.fuel.2017.04.089

Cited by 68 publications

(30 citation statements)

References 32 publications

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“…To ignite such a mixture, high ignition energies are needed 7 which can typically be provided either by pilot injection of a high-reactivity fuel (e.g. diesel, 8 alternatives such as poly(oxymethylene) dimethyl ethers (OME) 9 or blends), 10 by turbulent jet ignition using a prechamber or by alternative ignition concepts such as those discussed in previous studies. 11,12 As pilot injection requires a second fuel in combination with a comparably expensive high-pressure injection system and as pilot injection has problems to provide stable ignition with low pilot quantities at low load, 13,14 the use of a prechamber seems to be more attractive for light-duty vehicle use.…”

Section: Introductionmentioning

confidence: 99%

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Soltic

Hilfiker

Hänggi

2019

International Journal of Engine Research

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Diesel engines use diffusion-controlled combustion of a high-reactivity fuel and offer high efficiencies because they combine lean combustion with a high compression ratio. For low-reactivity fuels such as gasoline or natural gas, premixed combustion is used, which leads to lower efficiency levels as usually stoichiometric combustion is combined with lower compression ratios. Trying to apply diesel-like process parameters to low-reactivity fuels inevitably leads to problems with classical spark ignition systems as they are not able to establish robust flame propagation for such hard-to-ignite conditions. One possibility to enable fast combustion for diluted mixtures at high pressure levels is to establish ignition in a prechamber and ignite the charge of the main combustion chamber using the turbulent jets exiting the prechamber. In this study, the experimental results of a prechamber-equipped four-cylinder natural gas engine with 2 L displacement are discussed in detail. In the majority of the engine map, auxiliary fueling is used in the prechamber and a global air–fuel equivalence ratio λ is set to 1.7. At full load, a λ of 1.5 is applied without auxiliary prechamber fueling. The experiments show that such a setup is able to achieve brake efficiency levels of above 45% while maintaining peak brake mean effective pressure levels above 20 bar. At high load conditions, cylinder pressure levels at ignition timing achieve more than 80 bar and cylinder peak pressures of around 180 bars occur. The technology proved to enable robust and very fast combustion at comparably low NOx levels. A remaining challenge for the on-road use of such a technology is the reduction of the methane emissions at lean conditions.

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Section: Introductionmentioning

confidence: 99%

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Soltic

Hilfiker

Hänggi

2019

International Journal of Engine Research

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“…Considering methane deferring the ignition and inhibiting soot oxidation at the same time, the operational window in tradeoff between smokeless combustion and high engine UHC emissions or misfire might not be sufficiently wide to ensure smokeless operation over the whole engine operating map. Low sooting tendency of oxygenated fuels has been demonstrated in both Diesel engines and more fundamental investigations in constant volume chambers for a range of fuels: alcohols (methanol, butanol [29,30]), esters (methyldecanoate [31]), ethers (dimethylether, diethylether, POMDMEs [32,33,34,35,36,37,38,39]). Applications of oxygenates as pilot-fuels in dual-fuel engines (Imran with RME in [40] and Song with POMDME in [41]) confirmed the lower sooting tendency also in dual-fuel applications, and with some of the fuels even an extension of the engine operation limits with respect to the ignition was feasible.…”

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confidence: 99%

POMDME as an Alternative Pilot Fuel for Dual-Fuel Engines: Optical Study in a RCEM and Application in an Automotive Size Dual-Fuel Diesel Engine

Srna

Barro

Herrmann³

et al. 2018

SAE Technical Paper Series

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D ual-fuel natural gas engines are seen as an attractive solution for simultaneous reduction of pollutant and CO 2 emissions while maintaining high engine thermal efficiency. However, engines of this type exhibit a tradeoff between misfire as well as high UHC emissions for small pilot injection amounts and higher emissions of soot and NO X for operation strategies with higher pilot fuel proportion. The aim of this study was to investigate POMDME as an alternative pilot fuel having the potential to mitigate the emissions tradeoff, enabling smokeless combustion due to high degree of oxygenation, and being less prone to misfire due to its higher cetane number. Furthermore, POMDME can be synthetized carbon neutrally. First, characteristics of POMDME ignition in methane/ air mixture and the transition into premixed flame propagation were investigated optically in a rapid compression-expansion machine (RCEM) by employing Schlieren and OH* chemiluminescence imaging. A single-hole coaxial injector mounted at the cylinder periphery was used to admit POMDME or n-dodecane as the reference pilot fuel. In the second stage, POMDME was applied as a pilot-fuel in a VW 2 l 4-cylinder industrial Diesel engine modified for dual-fuel operation. Engine performance with POMDME and EN590 Diesel pilot-fuels was compared. In the RCEM, in air, dodecane and POMDME exhibit similar ignition delay times. In methane/air mixtures, ignition of both pilot fuels was deferred with increasing methane content, with stronger influence on POMDME than on dodecane. Indication of pilot-fuel over-mixing was observed for the shortest considered POMDME injections. In the engine experiment, while keeping the total combustion equivalence ratio constant, POMDME was found to have shorter ignition delays than Diesel fuel, attributed to its higher cetane number. At constant engine load using POMDME instead of Diesel pilot fuel, stable operation with lower pilot-fuel energy and mass input was possible along with soot mass reduction to close to zero.

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“…The baseline of the PM emission reduction relating to DMM/OME n is also their high oxygen content and further, the lack of C-C compounds, which increases the soot oxidation rate [52,53]. Similarly to butanol, these fuels show an increase of PM/PN reduction with increasing blending rates, but as a difference, they yield the highest emission reductions as neat fuels (see [56,57,62]). There are, however, some exceptions that need to be mentioned.…”

Section: Resultsmentioning

confidence: 99%

Future Fuels—Analyses of the Future Prospects of Renewable Synthetic Fuels

et al. 2019

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The Future Fuels project combines research in several institutes of the German Aerospace Center (DLR) on the production and use of synthetic fuels for space, energy, transportation, and aviation. This article gives an overview of the research questions considered and results achieved so far and also provides insight into the multidimensional and interdisciplinary project approach. Various methods and models were used which are embedded in the research context and based on established approaches. The prospects for large-scale fuel production using renewable electricity and solar radiation played a key role in the project. Empirical and model-based investigations of the technological and cost-related aspects were supplemented by modelling of the integration into a future electricity system. The composition, properties, and the related performance and emissions of synthetic fuels play an important role both for potential oxygenated drop-in fuels in road transport and for the design and certification of alternative aviation fuels. In addition, possible green synthetic fuels as an alternative to highly toxic hydrazine were investigated with different tools and experiments using combustion chambers. The results provide new answers to many research questions. The experiences with the interdisciplinary approach of Future Fuels are relevant for the further development of research topics and co-operations in this field.Synthetic fuels based on renewable energies (RE) are widely seen as a key element to achieving climate-neutral transport (e.g., [1,2]). As liquid hydrocarbons have a high energy and power density, they are primarily discussed as fuels for (heavy) road vehicles, ships, and aircraft. Due to their low storage and transport losses, they are also conceivable as a complementary long-term electricity storage option [3]. The challenges of producing and implementing these fuels are manifold. Chemical processes and renewable electrical or thermal energy can be used to produce liquid hydrocarbons from various carbon sources and hydrogen (and sometimes oxygen). Synthetic fuels have several advantages: they can be easily integrated into our existing energy and mobility infrastructures, can be used in all areas of the transport sector, and they can be optimized with regard to their chemical properties. The main disadvantages are the high energy losses and production costs.In this research context, eleven research groups at the German Aerospace Center (DLR) are working together on the Future Fuels project on synthetic fuels. The aim of the interdisciplinary approach is to realize synergies and joint research activities, as well as new research impulses through different perspectives. The scientists and engineers are investigating how synthetic fuels can be produced using solar energy and electrolysis processes (Solar Fuels), and are developing concepts for the re-conversion of these fuels into electricity. They are working on emission-optimized fuels for transport and aviation (Designer Fuels), as well as advanced space ap...

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POMDME-diesel blends: Evaluation of performance and exhaust emissions in a single cylinder heavy-duty diesel engine

Cited by 68 publications

References 32 publications

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

POMDME as an Alternative Pilot Fuel for Dual-Fuel Engines: Optical Study in a RCEM and Application in an Automotive Size Dual-Fuel Diesel Engine

Future Fuels—Analyses of the Future Prospects of Renewable Synthetic Fuels

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