High-speed PIV, spray, combustion luminosity, and infrared fuel-vapor imaging for probing tumble-flow-induced asymmetry of gasoline distribution in a spray-guided stratified-charge DISI engine

Zeng, Wei; Sjöberg, Magnus; Reuss, David L.; Hu, Zongjie

doi:10.1016/j.proci.2016.08.047

Cited by 29 publications

(9 citation statements)

References 11 publications

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“…For instance, the shortened gap between the fuel injection and spark timing accelerates flame propagation with less decayed turbulence intensity from the fuel injection [12]. In terms of cyclic variation, the fuel injection momentum can help reduce the variation of tumble structure formation [15], yet fluctuation of the injection could lead to higher cycle-to-cycle variations in the initial flame kernel development [14].…”

Section: Introductionmentioning

confidence: 99%

In-cylinder flow structure of a production spark-ignition engine at cold start conditions

Kim¹,

Rao²,

Oh³

et al. 2020

Australasian Fluid Mechanics Conference (AFMC)

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The problematic emissions during the cold start in a spark-ignition engine are mitigated by applying triple injection strategy and retarded ignition timing, which activate catalyst rapidly. However, in-cylinder flow development caused by the triple fuel injections has been little known in a modern high tumble engine. To bridge this gap, the present study implements endoscopic high-speed particle image velocimetry (eHS-PIV) in one of the four cylinders of a production engine employing direct injection technology and high tumble ratio design, which operates at the catalyst heating conditions. The results show that the triple fuel injection has a significant impact on in-cylinder flow structure by changing naturally developed tumble vortex direction and enhancing flow with the added injection-induced momentum. The increased flow velocity magnitude would help resolve the combustion instability caused by the implementation of late spark timing used for catalyst heating.

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Section: Introductionmentioning

confidence: 99%

In-cylinder flow structure of a production spark-ignition engine at cold start conditions

Kim¹,

Rao²,

Oh³

et al. 2020

Australasian Fluid Mechanics Conference (AFMC)

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“…Engine-out particulate matter (PM) is the net result of soot formation and oxidation in the bulk gas and can occur without wall wetting. For example, a study by Zeng et al 3 demonstrates that non-ideal gas flows can cause increased bulk-gas soot formation and elevated smoke for stratified-charge SI operation. Fuel impingement on combustion chamber surfaces and the resultant wall wetting can be a problem for stratified SI operation since the fuel is injected during the later stages of compression when the piston is approaching top dead center (TDC), sometimes with a short distance between the injector and the piston top, as compared to standard intake stroke injection strategies.…”

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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“…In addition, flame luminosity and spatial soot distributions can be captured using high-speed cameras and two-color pyrometry techniques. 15–17 Although various visualization methods provide data that reveal fundamental in-cylinder processes, only a subset are unobtrusive enough to be used in metal production engines.…”

Section: Introductionmentioning

confidence: 99%

Correlation of nanoparticle size distribution features to spatiotemporal flame luminosity in gasoline direct injection engines

Jeon

Bock

Kittelson

et al. 2018

International Journal of Engine Research

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Particle size distribution measured by mobility instruments is a common diagnostic used to characterize ultrafine and nanoparticle emissions in engine exhaust; however, some features of particle size distribution data are poorly correlated to in-cylinder combustion phenomena. In this work, in-cylinder spatiotemporal flame luminosity is quantitatively correlated to features in the solid particle size distribution measured in the exhaust of a gasoline direct injection engine operating in lean and stoichiometric combustion modes. A multi-channel optical sensor was used to measure diffusion flame light intensity in different areas of the combustion chamber. Total solid particle number and particle size distribution in the exhaust were measured using a scanning mobility particle sizer after a catalytic stripper that removed semi-volatile compounds. Results of the experiments showed that different flame phenomenon resulted in distinct particle size distribution characteristics. A large accumulation mode (particles with diameter of 50–100 nm) in the particle size distribution from stoichiometric engine operation with early injection resulted from anomalous diffusion flames like piston-top pool fires. In lean operation incorporating a secondary fuel injection, particle emissions were dominated by flame propagation through fuel-rich regions of the combustion chamber resulting in a comparatively broad particle size distribution. More generally, this work illustrates how particle size distribution data can be more accurately used to diagnose soot formation in gasoline direct injection engines.

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High-speed PIV, spray, combustion luminosity, and infrared fuel-vapor imaging for probing tumble-flow-induced asymmetry of gasoline distribution in a spray-guided stratified-charge DISI engine

Cited by 29 publications

References 11 publications

In-cylinder flow structure of a production spark-ignition engine at cold start conditions

In-cylinder flow structure of a production spark-ignition engine at cold start conditions

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

Correlation of nanoparticle size distribution features to spatiotemporal flame luminosity in gasoline direct injection engines

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