Comparing Enhanced Natural Thermal Stratification Against Retarded Combustion Phasing for Smoothing of HCCI Heat-Release Rates

Sjöberg, Magnus; Dec, John E.; Babajimopoulos, Aristotelis; Assanis, Dennis N.

doi:10.4271/2004-01-2994

Cited by 188 publications

(115 citation statements)

References 31 publications

Supporting

Mentioning

108

Contrasting

Order By: Relevance

“…Low Temperature Combustion engines have received widespread interest in this regard [1,2,3,4,5,6,7,8,9,10]. Many strategies have been explored and concepts such as Homogeneous Charge Compression Ignition (HCCI), Pre-mixed Charged Compression Ignition (PCCI) and Reactivity Controlled Compression Ignition (RCCI) engines have received attention over the last two decades.…”

Section: Introductionmentioning

confidence: 99%

Primary Reference Fuels (PRFs) as Surrogates for Low Sensitivity Gasoline Fuels

Shankar

Sajid

Al-Qurashi

et al. 2016

SAE Technical Paper Series

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Primary Reference Fuels (PRFs) as Surrogates for Low Sensitivity Gasoline Fuels

Shankar

Sajid

Al-Qurashi

et al. 2016

SAE Technical Paper Series

View full text Add to dashboard Cite

“…This can effectively prevent exceedingly high temporal gradients of the cylinder-pressure, as often observed, e.g., in HCCI engines at high loads. These "beneficial" effects have already been observed and analyzed (see, e.g., [7] and [5]). Studies towards finding the cause of the inhomogeneities (this issue is not addressed in this paper) have also been performed, by other authors, in a HCCI context [8].…”

Section: Introductionmentioning

confidence: 86%

Temperature Fluctuations in the Unburned Mixture: Indirect Visualisation Based on LIF and Numerical Simulations

Schießl¹,

Schubert²,

Maas³

2006

SAE Technical Paper Series

View full text Add to dashboard Cite

We apply a method for the visualization and semiquantitative estimation of small spatial temperature fluctuations in internal combustion engines with premixed loads. It is based on laser-induced fluorescence (LIF) of formaldehyde (CH 2 O), which is formed in the unburned gas near the end of the compression stroke. The chemical reactions leading to formaldehyde formation during the phase before auto-ignition are strongly temperaturedependent. The concentration of CH 2 O therefore acts as a natural, very sensitive tag for local gas temperature variations. A correlation between temperature fluctuation and formaldehyde concentration fluctuation is assessed by using numerical simulations involving a detailed treatment of chemical reactions leading to formaldehyde formation in the unburned gas. Formaldehyde is detected in the unburned gas of an optically accessible test SI engine by laser-induced fluorescence (LIF) along a line. The LIF-signal trace displays pronounced spatial fluctuations, which can not be attributed to inhomogeneities of the fuel/air ratio or to measurement noise, but which must be due to local temperature inhomogeneities in the unburned gas. By combining the observed spatial LIF-signal fluctuations with the computed formaldehyde/temperature correlations, temperature fluctuation amplitudes can be estimated. It is shown that the technique is capable of detecting fluctuations well below ±10 K before a mean temperature background of 800 K and higher.The results obtained by applying the method in a simple test engine give evidence that considerable temperature fluctuations exist in the unburned gas, both with respect to their amplitude and to their geometrical size. The information delivered by the method may be important especially in the field of auto-ignition in HCCI-engines, since local temperature inhomogeneities in the unburned gas can be of paramount influence for the subsequent development of self-ignition and combustion.

show abstract

“…The maximum cycle temperature was calculated via a 0D combustion analysis [3] using the in-cylinder pressure data. This analysis is based on the assumption that the combustion chamber temperature is uniform which is in general not the case since it has been shown that natural charge and thermal inhomogeneities tend to exist in HCCI combustion [13,16,17]. However, the analysis is nonetheless useful since it enables at least a comparative study for the various engine operating conditions and in particular the effect of equivalence ratio on engine-out HC emissions.…”

Section: Bulk Quenching 231 All-metal Engine Resultsmentioning

confidence: 99%

An Investigation of Unburned Hydrocarbon Emissions in Wall Guided, Low Temperature Diesel Combustion

Kashdan

Mendez

Bruneaux

2008

Oil & Gas Science and Technology - Rev. IFP

View full text Add to dashboard Cite

Résumé -Une investigation des émissions d'hydrocarbures imbrûlés en combustion Diesel à basse température avec guidage paroi -Les mécanismes de formation des hydrocarbures imbrûlés(HC) dans les systèmes de combustion à bas niveaux de NOx ont été investigués sur moteurs monocylindre opaque et optique fonctionnant à faible charge (2 et 4 bar de PMI). Sur moteur opaque, les paramètres tels que l'avance d'injection (AVI), la température plénum et la richesse globale ont été variés afin d'analyser le rôle du phénomène de quenching de masse sur la formation d'émissions de HC. La technique d'imagerie par fluorescence induite par laser (LIF) des HC imbrûlés à l'intérieur de la chambre a été appliquée sur le moteur optique. En outre, des essais ont été réalisés sur moteur opaque afin d'évaluer la contribution du volume mort du premier cordon sur les émissions de HC. Enfin, le rôle des films liquides et leur impact sur les émissions de HC ont été étudiés sur les deux types de moteurs. Sur moteur opaque l'investigation a consisté à comparer les résultats obtenus avec deux carburants dont les volatilités étaient différentes. En parallèle, la technique de LIF traceur a été appliquée sur moteur optique pour visualiser les films liquides. Les résultats obtenus sur les moteurs opaque et optique ont mis en évidence que le quenching de masse est une source majeure d'émission de HC dans le cas d'une géométrie de combustion avec guidage paroi. Le quenching de masse est le résultat de l'oxydation partielle du carburant dans les zones où la richesse locale est soit trop pauvre, soit trop riche et/ou la température locale n'est pas suffisamment élevée. Les données expérimentales obtenues sur les deux moteurs ont également révélé la présence de films liquides, surtout pour des stratégies d'injections précoces. En outre, les films liquides restent présents en fin de combustion, contribuant aux émissions de HC. Les images de LIF des films liquides semblent montrer que les films se détachent de la surface du piston pendant la phase de détente par un phénomène de « flash boiling ». Ces résultats semblent donc confirmer que le carburant non-brûlé issu des films liquides contribue directement aux émissions de HC. Abstract -An Investigation of Unburned Hydrocarbon Emissions in Wall Guided

show abstract

Comparing Enhanced Natural Thermal Stratification Against Retarded Combustion Phasing for Smoothing of HCCI Heat-Release Rates

Cited by 188 publications

References 31 publications

Primary Reference Fuels (PRFs) as Surrogates for Low Sensitivity Gasoline Fuels

Primary Reference Fuels (PRFs) as Surrogates for Low Sensitivity Gasoline Fuels

Temperature Fluctuations in the Unburned Mixture: Indirect Visualisation Based on LIF and Numerical Simulations

An Investigation of Unburned Hydrocarbon Emissions in Wall Guided, Low Temperature Diesel Combustion

Contact Info

Product

Resources

About