Time-Resolved Fuel Film Thickness Measurement for Direct Injection SI Engines Using Refractive Index Matching

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

International Journal of Engine Research ◽

10.1177/1468087419869785 ◽

2019 ◽

Vol 21 (2) ◽

pp. 302-318 ◽

Cited By ~ 2

Author(s):

Carl-Philipp Ding ◽

David Vuilleumier ◽

Namho Kim ◽

David L Reuss ◽

Magnus Sjöberg ◽

...

Keyword(s):

Refractive Index ◽

Direct Injection ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Injection Timing ◽

Fuel Film ◽

Index Matching ◽

Refractive Index Matching ◽

Wall Wetting ◽

Direct Injection Spark Ignition

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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Fuel film thickness measurements using refractive index matching in a stratified-charge SI engine operated on E30 and alkylate fuels

Experiments in Fluids ◽

10.1007/s00348-018-2512-5 ◽

2018 ◽

Vol 59 (3) ◽

Cited By ~ 13

Author(s):

Carl-Philipp Ding ◽

Magnus Sjöberg ◽

David Vuilleumier ◽

David L. Reuss ◽

Xu He ◽

...

Keyword(s):

Refractive Index ◽

Film Thickness ◽

Si Engine ◽

Fuel Film ◽

Stratified Charge ◽

Index Matching ◽

Refractive Index Matching ◽

Thickness Measurements

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Influence of Seawater Refractive Index on the Precision of Oil Film Thickness Measurement by Differential Laser Triangulation

Chinese Journal of Lasers ◽

10.3788/cjl201542.0408004 ◽

2015 ◽

Vol 42 (4) ◽

pp. 0408004

Author(s):

耿云飞 Geng Yunfei ◽

陈曦 Chen Xi ◽

金文 Jin Wen ◽

张惠群 Zhang Huiqun ◽

邬海强 Wu Haiqiang ◽

...

Keyword(s):

Refractive Index ◽

Film Thickness ◽

Thickness Measurement ◽

Laser Triangulation ◽

Oil Film ◽

Film Thickness Measurement

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Experimental Investigations on Fuel Spray and Impingement for Gasoline Direct Injection Engines

10.5772/intechopen.95848 ◽

2021 ◽

Author(s):

Hongliang Luo

Keyword(s):

Cooling System ◽

Direct Injection ◽

Fuel Spray ◽

Fuel Film ◽

Direct Injection Engines ◽

Index Matching ◽

Wall Impingement ◽

Refractive Index Matching ◽

Temperature Constant ◽

And Performance

Spray-wall impingement is a widespread phenomenon applied in many fields, including spray-wall cooling system, spray coating process and fuel spray and atomization in internal combustion engines. In direct-injection spark ignition (DISI), it is difficult to avoid the fuel film on the piston head and cylinder surfaces. The wet wall caused by impingement affects the air-fuel mixture formation process, which finally influence the subsequent combustion efficiency and performance. Therefore, the fuel spray and impingement under gasoline engine-like conditions were characterized. Mie scattering technique was applied to visualize the spray evolution and impingement processes in a high-pressure and high-temperature constant chamber. Meanwhile, the adhered fuel film on the wall was measured by refractive index matching (RIM) under non-evaporation and evaporation conditions considering the effects of different injection pressures, ambient pressures and ambient temperatures. Additionally, the fuel film formation and evaporation evolution models were proposed with the help of these mechanisms.

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