An Experimental Study on the Effect of Intake Primary Runner Blockages on Combustion and Emissions in SI Engines under Part-Load Conditions

Selamet, Ahmet; Rupal, S.; He, Yufei; Keller, Philip

doi:10.4271/2004-01-2973

Cited by 6 publications

(13 citation statements)

References 25 publications

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“…The calculation of 0 -10% and 10 -90% burn durations are based on the determination of the end of combustion (EOC) which is calculated by an improved combustion pressure rise method [8]. Knowing EOC, the mass fraction burned (mfb) can be specified by assuming proportionality to the fractional pressure rise due to combustion P from the time of spark: EOC mfb CAD , i spark spark P P (12) and then the burn durations can be quantified.…”

Section: Discussionmentioning

confidence: 99%

“…The measurements have been acquired for cylinders and intake runners 1 and 4. The detailed experimental setup has been described in Selamet et al [8]. Figure 2 shows the schematic of the flow lab setup including the instrumentation with a picture of this setup presented in Photo 1.…”

Section: Methodsmentioning

confidence: 99%

“…During compression, tumble compresses the flow vortex and significantly increases the angular velocity in order to maintain the angular momentum, which is usually called "spin-up" [5]. Near TDC, the tumble decays rapidly and breaks down into considerable small-scale turbulence leading to shortened burn duration, improved cyclic stability, and extended dilution limit [6][7][8][9][10]. Different levels of tumble motion are known to result in different engine performance, therefore it is important to design an optimum tumbling flow pertinent to specific combustion chamber architecture.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Impact of Tumble on Combustion in SI Engines: Correlation between Flow and Engine Experiments

He¹,

Selamet²,

Reese³

et al. 2007

SAE Technical Paper Series

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The introduction of tumble into the combustion chamber is an effective method of enhancing turbulence intensity prior to ignition, thereby accelerating the burn rates, stabilizing the combustion, and extending the dilution limit. In this study, the primary intake runners are partially blocked to produce different levels of tumble motion in the cylinder during the air induction process. Experiments have been performed with a Chrysler 2.4L 4-valve I4 engine at maximum brake torque timing under two operating conditions: 2.41 bar brake mean effective pressure (BMEP) at 1600 rpm, and 0.78 bar BMEP at 1200 rpm. A method has been developed to quantify the tumble characteristics of blockages under steady flow conditions in a flow laboratory, by using the same cylinder head, intake manifold, and tumble blockages from the engine experiments. A refined tumblemeter is installed under cylinder head to measure the compressive load of the tumble vortex, allowing for the calculation of angular momentum of the incoming air, tumble number, and tumble ratio at varying intake valve lifts. A correlation is then sought between the engine and flow experiments to help quantify the impact of tumble motion on combustion and cyclic variation. The air flow rate into the cylinder, discharge coefficient of the intake system, and the flow loss coefficient across the blockage are also analyzed for different levels of tumble motion. The validity of the method under steady flow conditions is confirmed by comparison of the results with the engine experiments.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of Tumble on Combustion in SI Engines: Correlation between Flow and Engine Experiments

He¹,

Selamet²,

Reese³

et al. 2007

SAE Technical Paper Series

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“…Swumble: an aerodynamic insert is added, as in the previous configuration, and the valve lift is modified: in Swumble mode one of the two intake valves is deactivated. In this way, the asymmetric intake flow combines the tumble and the swirl motion (hence the name Swumble) 22,23 . For the increased tumble and for the swumble case to assist the increased kinetic energy is slightly increased to a maximum of 0.564 bar.…”

Section: Working Conditions and Test Planmentioning

confidence: 99%

Experimental assessment of the sources of regulated and unregulated nanoparticles in gasoline direct-injection engines

Bardi

Pilla

Gautrot

2018

International Journal of Engine Research

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This work investigates nanoparticles formation process in light-duty GDI engines operated in homogeneous combustion. The analysis specifically focuses on the contribution of particles in the range of 10-23nm, which are expected to be taken into account in future emission regulations. Experiments were carried out on a single cylinder 0.4l displacement GDI optical engine. Exhaust gases were analysed by means of a commercial device (DMS500) to obtain a quantitative measurement of the particulates number and size. Optical diagnostics (broadband color imaging and liquid phase LIF) were employed to correlate the exhaust measurements to the in-cylinder physical phenomena. The main leverages to control soot particulates formation were investigated. The engine temperature was found to have a significant impact during the entire warm-up phase on the global particulates number (PN) and also on the relative contribution of the 10-23nm range to the total PN. Injection phasing has also a primary role in the formation of particulates in the small range of the spectrum when operating in mild stratified combustion mode. On the other hand, an increased in-cylinder aerodynamic (e.g. combined swirl-tumble motion) has a positive impact in reducing global particulates number but also causes an increase of the 10-23nm relative contribution. Optical diagnostics helped establishing a relationship between the detection of liquid film, the consequent pool fires and the exhaust gas measurements. The evaporation of the liquid film detected on the injector nozzle and the intake valve right after the injection appears to be decisive for the formation of nanoparticles in pool fire mode. The experimental results indicate that when pool fires were detected the PN increased drastically in the whole range of the spectrum including the 10-23nm range. Authors relate this effect to in-homogeneities in the fuel mixing field induced by the evaporation of the liquid film.

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“…It governs the fuel-air mixing, turbulence intensity, turbulent flame speed S T , hence the burn rate. As u' decreases, for example, under part-load operating conditions, where the throttling reduces the air flow rate as well as the volumetric efficiency v , S T is reduced and more cycle-to-cycle variations occur in the combustion chamber, leading to unstable combustion and possibly increased unburned HC and CO emissions [8]. Tumble and swirl are two types of charge motion studied extensively.…”

Section: Introductionmentioning

confidence: 99%

Effect of Intake Primary Runner Blockages on Combustion Characteristics and Emissions with Stoichiometric and EGR-diluted Mixtures in SI Engines

He¹,

Selamet²,

Reese³

et al. 2007

SAE Technical Paper Series

Self Cite

View full text Add to dashboard Cite

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An Experimental Study on the Effect of Intake Primary Runner Blockages on Combustion and Emissions in SI Engines under Part-Load Conditions

Cited by 6 publications

References 25 publications

Impact of Tumble on Combustion in SI Engines: Correlation between Flow and Engine Experiments

Impact of Tumble on Combustion in SI Engines: Correlation between Flow and Engine Experiments

Experimental assessment of the sources of regulated and unregulated nanoparticles in gasoline direct-injection engines

Effect of Intake Primary Runner Blockages on Combustion Characteristics and Emissions with Stoichiometric and EGR-diluted Mixtures in SI Engines

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