Oil Transport Phenomena during extreme load transients inside the power cylinder unit as investigated by HS-2DLIF (High-Speed 2D Laser-Induced Fluorescence)

Ahling, Sebastian; Tian, Tian

doi:10.4271/2019-01-2363

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…Therefore, the oil should be prevented from filling the top ring groove by improving both engine design and control strategies. Similar behavior was also observed by Ahling [12] with a different TPOCR design, which also compared the different oil controlling ability between a Twin-Land Oil Control Ring, referred to as TLOCR hereafter, and Three-Piece Oil Control Ring, referred as TPOCR hereafter. Furthermore, Wachtmeister [13] used the similar 2D-LIF technique to investigate oil transport and observed that oil droplets can be transported into the combustion chamber in high speed and low load conditions due to increased inertia force and lowered cylinder pressure.…”

Section: Introductionsupporting

confidence: 73%

“…The test engine (Table 1) is the same engine used in previous work [4,5,[9][10][11][12][16][17][18], which is a single cylinder research engine with a custom-made optical liner (Figure 1), allowing for a high-speed camera to record the lubrication oil movement as the piston moves. A cylinder head based on a PSA in line with a four-cylinder production engine with the three unused cylinders deactivated was used.…”

Section: Experimental Setup 21 Engine Setupmentioning

confidence: 99%

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Effect of Blowby on the Leakage of the Three-Piece Oil Control Ring and Subsequent Oil Transport in Upper Ring-Pack Regions in Internal Combustion Engines

Tian

2022

Lubricants

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The lubricating oil consumption (LOC) in internal combustion engines contributes to emission and deteriorates the performance of the aftertreatment. In this work, an optical engine with a 2D Laser-induced fluorescence (2D-LIF) system was used to study operating conditions critical to real driving oil emissions. Additionally, numerical models were used to analyze the ring dynamics, oil flow and gas flow. It was found that the intake pressure that results in zero blowby is the separation line between two drastically different oil flow patterns in the ring pack. With intake pressure lower than the separation line, the oil accumulation of the three-piece oil control ring groove (TPOCR) begins to increase, followed by the drastic increase of the oil accumulation in the third land, second land, and finally visible oil leaking through the top ring gap, given enough time. The time required for the oil to leak through different rings was investigated using both measurements and modeling. The effects of drain holes and rail gaps, as well as their relative rotation on oil accumulation and leakage from the TPOCR groove, were analyzed. These findings contribute to improving ring pack designs and engine calibration in spark ignition (SI), gas, and hydrogen engines equipped with TPOCR to minimize the negative impacts of LOC.

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Section: Introductionsupporting

confidence: 73%

Section: Experimental Setup 21 Engine Setupmentioning

confidence: 99%

Effect of Blowby on the Leakage of the Three-Piece Oil Control Ring and Subsequent Oil Transport in Upper Ring-Pack Regions in Internal Combustion Engines

Tian

2022

Lubricants

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“…The experiments in this work were performed with wide-open throttle, while oil transport to the upper piston region is more promoted by a closed throttle and long periods of motored operation. 47,48…”

Section: Resultsmentioning

confidence: 99%

Quantitative fluorescence-based imaging of in-cylinder fuel film thickness at kHz frame rates in a production-type direct-injection spark-ignition engine

Schöler

Wigger

Kaiser

2022

International Journal of Engine Research

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Incomplete evaporation of liquid fuel films inside the combustion chamber is a major source of soot and particulate emissions in internal combustion engines. In this study, quantitative imaging of liquid fuel films on the cylinder wall is performed by laser-induced fluorescence (LIF) in a single cylinder engine with optical access to the cylinder liner. A four-component surrogate fuel mixed with 0.5% anisole as the fluorescent tracer was directly injected in a single injection into the motored engine. Fuel impinging on the cylinder wall is excited at 266 nm at kHz repetition rates and imaged by a high-speed camera coupled with an image intensifier. Simultaneously, lubricating oil doped with 0.01 mmol/l pyrromethene 567 is excited at 532 nm and imaged with a second camera. The fuel film thickness on the cylinder wall is compared for two different injections timings, 285 and 240°CA before top-dead center. The initial fuel film thickness is similar for both, but evaporation occurs faster for the later injection, such that the film thickness is similar at the time the piston rings reach the fuel films. When the rings scrape the fuel off the wall, it accumulates on top of the first piston ring and is partly transported downwards to the second and third ring. In the simultaneous oil image, washout of lubricating oil is seen.

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Experimental Investigation of Oil Transport during Low Load to High Load Transient in Internal Combustion Engines

Tian

2023

Lubricants

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Reducing the Lubricating Oil Consumption (LOC) has been a critical focus for engine manufacturers. LOC not only depends on engine operating condition but also the history of the operating condition variations. This work seeks to understand the oil transport in the ring pack during the low load to high load transient through experimental investigations. An optical engine with 2D Laser Induced Fluorescence (2D-LIF) technique, equipped with a modern low-tension Three-Piece Oil Control Ring (TPOCR), was applied to investigate the oil transport in the ring pack. It was found that, after the engine stayed under the blowby separation line long enough, a sudden increase to high load can result in a huge increase of oil ejection to the liner from the top ring groove in the expansion strokes. The mechanism behind it is that, when the load is increased, the oil accumulated inside the top ring groove during the low load condition is pushed out by the gas flow after the peak cylinder pressure is reached. Different combinations of load, speed, rate of change in load and time duration at low load were tested to examine their influence on this leakage mechanism. An operation with a gradual increase of engine load was found to be able to reduce the amount of oil leaked to the liner by releasing more oil to the second land. These findings can help the effort to reduce the oil emission (OE) generated from Spark Ignited (SI) engines equipped with TPOCR in the real-world transient driving conditions as well as the emission tests.

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Oil Transport Phenomena during extreme load transients inside the power cylinder unit as investigated by HS-2DLIF (High-Speed 2D Laser-Induced Fluorescence)

Cited by 5 publications

References 3 publications

Effect of Blowby on the Leakage of the Three-Piece Oil Control Ring and Subsequent Oil Transport in Upper Ring-Pack Regions in Internal Combustion Engines

Effect of Blowby on the Leakage of the Three-Piece Oil Control Ring and Subsequent Oil Transport in Upper Ring-Pack Regions in Internal Combustion Engines

Quantitative fluorescence-based imaging of in-cylinder fuel film thickness at kHz frame rates in a production-type direct-injection spark-ignition engine

Experimental Investigation of Oil Transport during Low Load to High Load Transient in Internal Combustion Engines

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