An Experimental Investigation of In-Cylinder Processes Under Dual-Injection Conditions in a DI Diesel Engine

Mueller, Charles J.; Martin, Glen C.; Briggs, Thomas; Duffy, K. P.

doi:10.4271/2004-01-1843

Cited by 41 publications

(21 citation statements)

References 22 publications

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“…Ideally, it would be possible to quantitatively and non-intrusively measure the incylinder NO x -production rate and NO x distribution with a high degree of spatial and temporal resolution. Unfortunately, such measurements of NO x -relevant species (e.g., NO, NO 2 , N 2 , N, O 2 , O, OH, and H) and charge-gas temperature at typical diesel-engine conditions are not currently possible, and it is not clear when they will be (see e.g., [33,52,53]). In the mean time, it seems justifiable to use existing knowledge combined with thought experiments to help elucidate a "big picture" view of the mechanisms that determine fuel effects on NO x emissions, even though the thought experiments must necessarily contain some unproven assumptions.…”

Section: Discussionmentioning

confidence: 99%

“…Motored top-dead-center (TDC) conditions in the 16.0:1 compression-ratio engine were matched in the present study. Further details of the SCORE can be found in [33] and [34].…”

Section: Engine -The Sandia Compression-ignition Opticalmentioning

confidence: 99%

“…This result may not be surprising based on observed spray asymmetries with VCO-type nozzles such as the one used in this study (e.g., see Figs. 4 and 9 of [33]). LOL i  is the average of LOL i over all 6 jets for a given fuel and dilution condition.…”

Section: Biodiesel Effects On Combustion Phasing -mentioning

confidence: 99%

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An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

Mueller¹,

Boehman²,

Martin³

2009

SAE Int. J. Fuels Lubr.

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319

233

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The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under the supervision of the session organizer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. ISSN 0148-7191 Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. SAE ABSTRACTIt is generally accepted that emissions of nitrogen oxides (NO x ) increase as the volume fraction of biodiesel increases in blends with conventional diesel fuel. While many mechanisms based on biodiesel effects on incylinder processes have been proposed to explain this observation, a clear understanding of the relative importance of each has remained elusive.To gain further insight into the cause(s) of the biodiesel NO x increase, experiments were conducted in a singlecylinder version of a heavy-duty diesel engine with extensive optical access to the combustion chamber. The engine was operated using two biodiesel fuels and two hydrocarbon reference fuels, over a wide range of loads, and using undiluted air as well as air diluted with simulated exhaust gas recirculation. Measurements were made of cylinder pressure, spatially integrated natural luminosity (a measure of radiative heat transfer), engine-out emissions of NO x and smoke, flame lift-off length, actual start of injection, ignition delay, and efficiency. Adiabatic flame temperatures for the test fuels and a surrogate #2 diesel fuel also were computed at representative diesel-engine conditions.Results suggest that the biodiesel NO x increase is not quantitatively determined by a change in a single fuel property, but rather is the result of a number of coupled mechanisms whose effects may tend to reinforce or cancel one another under different conditions, depending on specific combustion and fuel characteristics. Nevertheless, charge-gas mixtures that are closer to stoichiometric at ignition and in the standing premixed autoignition zone near the flame liftoff length appear to be key factors in helping to explain the biodiesel NO x increase under all conditions. These differences are expected to lead to higher local and average in-cylinder temperatures, lower radiative heat losses, and a shorter, more-advanced combustion event, all of which would be expected to increase thermal NO x emissions. Differences in prompt NO formation and species concentrations resulting from fuel and jet-structure changes also may play important roles.

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Section: Discussionmentioning

confidence: 99%

“…Motored top-dead-center (TDC) conditions in the 16.0:1 compression-ratio engine were matched in the present study. Further details of the SCORE can be found in [33] and [34].…”

Section: Engine -The Sandia Compression-ignition Opticalmentioning

confidence: 99%

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An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

Mueller¹,

Boehman²,

Martin³

2009

SAE Int. J. Fuels Lubr.

Self Cite

319

233

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“…In this context, recent studies have focused on achieving pre-mixed, low-temperature combustion (LTC) in order to reduce emissions without any detrimental effect on fuel consumption and energy density. Different strategies that have been investigated include homogeneously charged compression ignition (HCCI) (Tanaka et al 2003, Kong and Reitz 2002, Dec 2009, and Mueller et al 2004, modulated kinetics (MK) concept (Kimura et al 2001), premixed charge compression ignition (PCCI) (Diwakar and Singh 2008), and reactivity controlled compression ignition (RCCI) (Reitz 2012). While there are some differences in these strategies, the underlying concept is to avoid high-temperature and fuel rich (high equivalence ratio (φ)) regions.…”

Section: Introductionmentioning

confidence: 99%

Effects of fuel reactivity and injection timing on diesel engine combustion and emissions

Xiao

Wijeyakulasuriya

2014

International Journal of Green Energy

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Recent strategies for simultaneously reducing NOx and soot emissions have focused on achieving nearly premixed, low-temperature combustion in diesel engines. A promising approach in this regard is to vary fuel reactivity in order to control the ignition delay and optimize the level of premixing and reduce emissions. The present study examines such a strategy by performing 3-D simulations in a single-cylinder of a diesel engine. Simulations employ the state-of-the-art two-phase models and a validated semi-detailed reaction mechanism.The fuel reactivity is varied by using a blend of n-heptane and iso-octane, which represent surrogates for gasoline and diesel fuels, respectively. Results indicate that the fuel reactivity A c c e p t e d M a n u s c r i p t 2 strongly influences ignition delay and combustion phasing, whereas the start of injection (SOI) affects combustion phasing. As fuel reactivity is reduced, the ignition delay is increased and the combustion phasing is retarded. The longer ignition delay provides additional time for mixing, and reduces equivalence ratio stratification. Consequently, the premixed combustion is enhanced relative to diffusion combustion, and thus the soot emission is reduced. NOx emission is also reduced due to reduced diffusion combustion and lower peak temperatures caused by delayed combustion phasing. An operability range is observed in terms of fuel reactivity and SOI, beyond which the mixture may not be sufficiently well mixed, or compression ignited. The study demonstrates the possibility of finding an optimum range of fuel reactivity, SOI, and EGR for significantly reducing engine out emissions for a given load and speed.

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“…Relative to 1994 regulations, these aggressive targets represent reductions by factors of 150 and 100 respectively in these pollutants. There is as yet no consensus on how to achieve both targets simultaneously in a cost-effective manner and with-out suffering significant performance penalties [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

An investigation of mixture formation and in-cylinder combustion processes in direct injection diesel engines using group-hole nozzles

Gao

Matsumoto

Namba

et al. 2009

International Journal of Engine Research

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Mixture properties of the transient fuel spray injected by group-hole nozzles were quantitatively studied in a constant volume chamber via the laser absorption scattering (LAS) technique, and compared with conventional single-hole nozzles. Specific areas investigated included non-evaporating and evaporating ambient conditions, and the conditions of free spray and spray impinging on a flat wall. The particular emphasis was on the effect of one of the key parameters of the group-hole nozzle structure, namely, the interval between orifices. Subsequently, in-cylinder ignition and combustion processes were investigated by direct flame visualization in a single-cylinder optical research engine using the group-hole nozzle and the standard multi-hole nozzle, together with heat release analysis. Results show that the grouphole nozzle can produce a smaller Sauter mean diameter (SMD) of droplets under the nonevaporating condition. Under the evaporating condition, for the free spray cases, there exists a trade-off between the fuel evaporation and the spray penetration in the application of the group-hole nozzle. With the increase in interval between orifices, the ratio of evaporation increases, but the spray tip penetration decreases. For the spray impinging on a flat wall, the group-hole nozzle can enhance the spray tip penetrations to some extent compared with the single-hole nozzles. Flame images taken in a direct injection optical engine show that the enhancement of the fuel atomization and evaporation by the group-hole nozzle may contribute to a decrease in overall flame luminosity level, suggesting reduced soot formation in diesel engines.

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An Experimental Investigation of In-Cylinder Processes Under Dual-Injection Conditions in a DI Diesel Engine

Cited by 41 publications

References 22 publications

An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

Effects of fuel reactivity and injection timing on diesel engine combustion and emissions

An investigation of mixture formation and in-cylinder combustion processes in direct injection diesel engines using group-hole nozzles

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An Experimental Investigation of In-Cylinder Processes Under Dual-Injection Conditions in a DI Diesel Engine

Cited by 41 publications

References 22 publications

An Experimental Investigation of the Origin of Increased NOxEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

An Experimental Investigation of the Origin of Increased NOxEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

Effects of fuel reactivity and injection timing on diesel engine combustion and emissions

An investigation of mixture formation and in-cylinder combustion processes in direct injection diesel engines using group-hole nozzles

Contact Info

Product

Resources

About

An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel