On the origin of Unburned Hydrocarbon Emissions in a Wall Guided, Low NOx Diesel Combustion System

Kashdan, Julian T.; Mendez, Sylvain; Bruneaux, Gilles

doi:10.4271/2007-01-1836

Cited by 59 publications

(29 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The higher bulk gas temperatures not only affect ignition timing but also the level of HC (and presumably CO) emissions. As previously reported in Reference [8], bulk quenching has been shown to be a significant source of HC emissions, due to excessively low combustion temperatures leading to incomplete oxidation. Since HC formation as a result of bulk quenching is closely coupled to temperature, the significantly higher combustion temperatures which are achieved as a result of lower thermal conductivities in optical engine combustion chambers leads to a major reduction in HC emissions levels (Fig.…”

Section: Materials and Heat Transfer Effectsmentioning

confidence: 67%

“…Indeed this would explain why the measured engine-out HC emissions are significantly lower on the optical engine as revealed in Figure 18 since the higher combustion temperatures encountered on the optical engine will tend to ensure that more of the bulk-gas reactions go to completion. As reported in Reference [8], bulk quenching has been identified as a potentially major source of unburned HC emissions in Diesel LTC engines. For SOI timings in the range 340 to 355°CA, similar combustion phasing was well matched between the two engines and Figure 18 reveals that this also correlates with similar levels of engine-out HC emissions.…”

Section: Materials and Heat Transfer Effectsmentioning

confidence: 99%

“…sapphire or quartz rings) requires that the upper piston rings are lowered (compared with a standard all-metal piston) so as to avoid overlap (and subsequent sealing problems) of the piston rings at the interface between the metal liner and the transparent ring. This difference inevitably leads to an increased piston top land crevice volume [8] which will reduce the engine Compression Ratio (CR). Other geometrical parameters such as the squish height and the injector nozzle tip protrusion should also be similar between both engines so as not to adversely affect the in-cylinder airflow/turbulence and jet-wall impingement location respectively.…”

Section: Geometry and Engine Architectural Considerationsmentioning

confidence: 99%

“…More recently, studies of in-cylinder combustion processes are tending to rely upon a combined approach whereby experiments are performed on both an optical and an identical, standard, all-metal engine [8,18,19]. There are clearly several advantages to such an approach.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts

Kashdan

Thirouard

2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

Résumé -Moteurs transparents comme outils représentatifs dans le développement de nouveaux concepts des moteurs à combustion interne -Les moteurs monocylindres transparents sont employés comme outils de recherche et de développement des moteurs à combustion interne. Ils permettent l'utilisation de techniques de diagnostics non-intrusifs (qualitatifs et quantitatifs) pour étudier des phénomènes comme l'aérodynamique interne, la préparation du mélange, la combustion et la formation de polluants. Ces données expérimentales sont importantes pour la validation des modèles numériques et permettent également d'obtenir une compréhension détaillée des phénomènes physiques se déroulant dans la chambre. Les données recueillies aident au développement des nouvelles stratégies de combustion telles que la combustion homogène (HCCI) et la combustion Diesel à basse température (LTC). Dans ce contexte, il est important de s'assurer que le fonctionnement des moteurs transparents est tout à fait comparable et représentatif de celui des moteurs standards (opaques). Une comparaison du comportement de la combustion et des émissions des moteurs transparents et opaques a été réalisée. L'objectif était d'étudier les différences principales entre le moteur transparent et le moteur opaque et de comprendre comment ces différences peuvent influencer les phases de préparation du mélange, la combustion et la formation de polluants. Les résultats expérimentaux révèlent l'influence significative des différences liées à la température des parois de la chambre de combustion. Des mesures de la température des parois ont été effectuées par la technique de phosphorescence induite par laser. Ces mesures ont permis de définir des stratégies de fonctionnement moteur permettant de compenser les différences de température de paroi entre les deux moteurs. En outre, l'impact des différences géométriques des chambres a été investiguée. La réhausse piston peut subir soit un chargement mécanique dynamique (effets de compression ou de traction) soit une expansion thermique. Ces effets peuvent faire varier le taux de compression effectif. La charge admise dans les moteurs transparents est souvent diluée par de l'EGR simulé au lieu d'utiliser l'EGR réel. Dans les conditions de Diesel LTC, une comparaison a été effectuée entre l'utilisation d'EGR réel et d'EGR simulé par un gaz diluant pur. Enfin, les carburants mono-composants (carburants purs) sont souvent utilisés dans les moteurs Diesel transparents en raison des contraintes imposées par l'utilisation de techniques de diagnostics optiques. Cependant, les carburants purs diffèrent quelque peu des carburants Diesel réels, en particulier au travers de leur indice de cétane et de leur volatilité. Ces différences peuvent influencer fortement le comportement de la combustion et des émissions dans les moteurs transparents. Ces aspects ont été également traités dans cette étude. Une meilleure compréhension des différences de comportement entre les moteurs monocylindres transparents et moteurs standards (opaques) a pe...

show abstract

Section: Materials and Heat Transfer Effectsmentioning

confidence: 67%

Section: Materials and Heat Transfer Effectsmentioning

confidence: 99%

Section: Geometry and Engine Architectural Considerationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts

Kashdan

Thirouard

2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

show abstract

“…Spray penetration, which is usually analysed macroscopically, considers the development of the liquid and vapour components. It is desirable to achieve optimal travel of these spray components to avoid the adverse effects of impingement caused by under/overpenetration of liquid spray [19,20]. Advances in fuel injection system, with the introduction of the common rail technology, have provided increased controllability of the injection event.…”

Section: Introductionmentioning

confidence: 99%

Fuel spray vapour distribution correlations for a high pressure diesel fuel spray cases for different injector nozzle geometries.

Njere

Emekwuru

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

View full text Add to dashboard Cite

The evolution of diesel fuel injection technology, to facilitate strong correlations of in-cylinder spray propagation with injection conditions and injector geometry, is crucial in facing emission challenges. More observations of spray propagation are, therefore, required to provide valuable information on how to ensure that all the injected fuel has maximum contact with the available air, to promote complete combustion and reduce emissions. In this study, high pressure diesel fuel sprays are injected into a constant-volume chamber at injection and ambient pressure values typical of current diesel engines. For these types of sprays the maximum fuel liquid phase penetration is different and reached sooner than the maximum fuel vapour phase penetration. Thus, the vapour fuel could reach the combustion chamber wall and could be convected and deflected by swirling air. In hot combustion chambers this impingement can be acceptable but this might be less so in larger combustion chambers with cold walls. The fuel-ambient mixture in vapourized fuel spray jets is essential to the efficient performance of these engines. For this work, the fuel vapour penetration values are presented for fuel injectors of different k-factors. The results indicate that the geometry of fuel injectors based on the k-factors appear to affect the vapour phase penetration more than the liquid phase penetration. This is a consequence of the effects of the injector types on the exit velocity of the fuel droplets. KeywordVapour, spray, k-factor, shadowgraph. IntroductionSpray formation occurs with the introduction of liquid into a gaseous environment through an orifice such that the liquid breaks-up into droplets by interacting with the surrounding gases and causing its own unsteadiness [3]. For diesel engines, spray characteristics (liquid/vapour penetration and distribution) significantly affect the combustion and emission processes. By optimizing these characteristics, the tailpipe emissions, mainly oxides of Nitrogen (NOx) and partciculate matter (PM), can be minimized [2]. Spray penetration, which is usually analysed macroscopically, considers the development of the liquid and vapour components. It is desirable to achieve optimal travel of these spray components to avoid the adverse effects of impingement caused by under/overpenetration of liquid spray [19,20]. Advances in fuel injection system, with the introduction of the common rail technology, have provided increased controllability of the injection event. The analyses of injection system development have been presented from several viewpoints. Nozzle geometry has been studied for the influence on the internal flow and spray characteristics with respect to: atomization [4,5], mixing processes [6,7], emission [9,10] and cavitation [8,13]. Different injection strategies have been investigated to show the effect on pollutant emissions [2,3]. Specific studies have also been conducted with conical and cylindrical nozzles [11,12], and to develop more understanding on the effects of nozzl...

show abstract

Emission Characteristics

Maurya¹

2017

Mechanical Engineering Series

View full text Add to dashboard Cite

On the origin of Unburned Hydrocarbon Emissions in a Wall Guided, Low NOx Diesel Combustion System

Cited by 59 publications

References 21 publications

Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts

Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts

Fuel spray vapour distribution correlations for a high pressure diesel fuel spray cases for different injector nozzle geometries.

Emission Characteristics

Contact Info

Product

Resources

About