Liquid and Vapor Envelopes of Sprays from a Multi-Hole Fuel Injector Operating under Closely-Spaced Double-Injection Conditions

Parrish, Scott; Zhang, Gaoming; Zink, Ronald J.

doi:10.4271/2012-01-0462

Cited by 21 publications

(12 citation statements)

References 9 publications

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“…Most studies showed a reduction in engine-out soot with the addition of a post injection at some dwell and duration, but there was no dwell and duration combination that clearly and universally lead to soot reduction [10,15,16,17,18,19,20,27,28,31,38,39,40,41,73,74]. Researchers reported that often a "sweet spot" could be reached where engine-out soot was minimized [15,19,21,22,24,28,33,34,73].…”

Section: Injection Schedulingmentioning

confidence: 99%

“…Even without wall interactions, however, variation in jet development and mixing characteristics of main-plus-postinjection schedules have been measured. Two such examples are the unconfined diesel sprays (i.e., free jets) studied at engine conditions by Bruneaux and Maligne [88] and Parrish et al [74]. Under certain close-coupled operating conditions in both these studies, the jet structure of the first injection was altered by the second injection, changing mixing characteristics even without the interaction of the jet with engine surfaces.…”

Section: Figure 18 Soot-no X Trade-off For Two Injector Included Angmentioning

confidence: 99%

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Post Injections for Soot Reduction in Diesel Engines: A Review of Current Understanding

O’Connor

Musculus

2013

SAE Int. J. Engines

140

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This work is a technical review of past research and a synthesis of current understanding of post injections for soot reduction in diesel engines. A post injection, which is a short injection after a longer main injection, is an in-cylinder tool to reduce engine-out soot to meet pollutant emissions standards while maintaining efficiency, and potentially to reduce or eliminate exhaust aftertreatment. A sprawling literature on post injections documents the effects of post injections on engine-out soot with variations in many engine operational parameters. Explanations of how post injections lead to engineout soot reduction vary and are sometimes inconsistent or contradictory, in part because supporting fundamental experimental or modeling data are often not available. In this paper, we review the available data describing the efficacy of post-injections and highlight several candidate in-cylinder mechanisms that may control their efficacy. We first discuss three in-cylinder mechanisms that have been frequently proposed to explain how post injections reduce engine-out soot. Thereafter, to provide a foundation for interpretation of past research, we briefly review basic soot formation and oxidation chemistry, and soot/fluid processes in fuel sprays and engine flows. Next, we provide a comprehensive overview of the literature on the efficacy of post-injections for soot reduction as a function of engine operational parameters including injection duration and dwell, exhaust-gas recirculation, load, boost, speed, swirl, and spray targeting. We conclude by identifying major remaining research questions that need to be addressed to help achieve a design-level understanding of the mechanisms of soot reduction by post injections.

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Section: Injection Schedulingmentioning

confidence: 99%

Section: Figure 18 Soot-no X Trade-off For Two Injector Included Angmentioning

confidence: 99%

Post Injections for Soot Reduction in Diesel Engines: A Review of Current Understanding

O’Connor

Musculus

2013

SAE Int. J. Engines

140

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“…Specifically, the concept of direct injection (DI) applied to SI engines is to this day studied with renewed interest [1,2,3] because it allows for reduction of knock effects, better coldstart performances and overall higher efficiency. However, since full outer spray angle values for gasoline direct injection (GDI) sprays are narrower compared to diesel jets (from 60° to 90° compared to the 140°-160° range of diesels [4]), it was necessary to carry out experimental works to study the effects of the GDI spray evolution on fuel consumption and pollutant emissions [5] under both non-evaporating [6] and engine-like conditions [7,8,9]. Factors affecting the spray collapse [10,11] as well as f lash boiling phenomena [12,13] were also investigated.…”

mentioning

confidence: 99%

Combined Experimental and Numerical Investigation of the ECN Spray G under Different Engine-Like Conditions

Paredi¹,

Lucchini²,

D’Errico³

et al. 2018

SAE Technical Paper Series

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A detailed understanding of Gasoline Direct Injection (GDI) techniques applied to spark-ignition (SI) engines is necessary as they allow for many technical advantages such as increased power output, higher fuel efficiency and better cold start performances. Within this context, the extensive validation of multi-dimensional models against experimental data is a fundamental task in order to achieve an accurate reproduction of the physical phenomena characterizing the injected fuel spray. In this work, simulations of different Engine Combustion Network (ECN) Spray G conditions were performed with the Lib-ICE code, which is based on the open source OpenFOAM technology, by using a RANS Eulerian-Lagrangian approach to model the ambient gas-fuel spray interaction. Foremost, the main scope of the activity was to identify the most accurate numerical setup in terms of atomization ad secondary break-up models, thanks to a validation of the computed results against experimental data available for the ECN Spray G baseline condition. Specifically, attention was focused on spray penetration along with an analysis of spray morphology and effects of plume-to-plume interaction. Afterwards, the reference setup was tested and validated under different operating conditions, characterized by detailed experimental measurements specifically provided for this work. In particular, Mie scattering and Schlieren techniques allowed the quasi-simultaneous acquisition of both vapor and liquid penetrations, while a customized imageprocessing procedure, developed in Matlab environment, was used for the outline of the spray contours of both fuel phases to measure the parameters characterizing the jet development. A robust reference numerical setup was identified, capable to reproduce with good accuracy the injection process of a multi-hole GDI spray under the wide range of tested operating conditions. COMBINED EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE ECN SPRAY G

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“…Studies in quiescent chambers have demonstrated that the sprays from multi-hole injectors (in the absence of flash boiling at high fuel temperature and low ambient-gas pressure) initially create a hollow-cone spray, that is, a conical curtain of individual spray jet plumes. The plumes can remain separate or merge and “collapse” as observed by Parrish et al, 9 depending on ambient conditions and injection characteristics. Sphicas et al 11 provide a comprehensive state-of-the-art review and description of the temporal evolution of the Engine Combustion Network (ECN) Spray G multi-hole gasoline injector, which is generically similar to the injector used here.…”

Section: Resultsmentioning

confidence: 86%

“…The extreme manifestation of plume interaction is “spray collapse,” where all plumes merge to a single plume. Light scattering (the label “light scattering” is used to include all elastically scattered light as well as light reflection and/or refraction by large-scale droplets and window-surface roughness) and Schlieren imaging used to capture the macroscopic features of the spray revealed that spray collapse can occur at increased ambient pressures, 9 conditions which are found during late injection. The separation of the plumes was observed to progressively decrease during the injection event in cases of spray collapse.…”

Section: Introductionmentioning

confidence: 99%

Effect of engine conditions and injection timing on piston-top fuel films for stratified direct-injection spark-ignition operation using E30

Ding

Vuilleumier

Kim

et al. 2019

International Journal of Engine Research

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Mid-level ethanol/gasoline blends can provide knock resistance benefits for stoichiometric spark-ignition engine operation, but previous studies have identified challenges associated with spray impingement and wall wetting, leading to excessive particulate matter emissions. At the same time, stratified-charge spark-ignition operation can provide increased thermal efficiency, but care has to be exercised to avoid excessive in-cylinder soot formation. In support of the use of mid-level ethanol/gasoline blends in advanced spark-ignition engines, this study presents spray and fuel-film measurements in a direct-injection spark-ignition engine operated with a 30 vol.%/70 vol.% ethanol/gasoline blend (E30). Crank-angle resolved fuel-film measurements at the piston surface are conducted using two different implementations of the refractive index matching technique. A small-angle refractive index matching implementation allows quantification of the wetted area, while a large-angle refractive index matching implementation enables semi-quantitative measurements of fuel-film thickness and volume, in addition to fuel-film area. The fuel-film measurements show that both the amount of fuel deposited on the piston and the shape of the fuel-film patterns are strongly influenced by the injection timing, duration, intake pressure, and coolant temperature. For combinations of high in-cylinder gas density and long injection duration, merging of the individual spray plumes, commonly referred to as spray collapse, can cause a dramatic change to the shape and thickness of the wall fuel films. Overall, the study provides guidance to engine designers aiming at minimizing wall wetting through tailored combinations of injection timings and durations.

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Liquid and Vapor Envelopes of Sprays from a Multi-Hole Fuel Injector Operating under Closely-Spaced Double-Injection Conditions

Cited by 21 publications

References 9 publications

Post Injections for Soot Reduction in Diesel Engines: A Review of Current Understanding

Post Injections for Soot Reduction in Diesel Engines: A Review of Current Understanding

Combined Experimental and Numerical Investigation of the ECN Spray G under Different Engine-Like Conditions

Effect of engine conditions and injection timing on piston-top fuel films for stratified direct-injection spark-ignition operation using E30

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