Effect of Intake Port Flow Pattern on the In-Cylinder Tumbling Air Flow in Multi-Valve SI Engines

Omori, Shuichi; Iwachido, Kinichi; Motomochi, M.; Hirako, Osamu

doi:10.4271/910477

Cited by 53 publications

(15 citation statements)

References 4 publications

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“…Figure 19 illustrates the increase in LNV to 97.7% and 98.7% for 40% and 20%-open blockages at WP, in contrast to 96.1% for the unblocked runner, whereas the values at IP are 84%, 92.2%, and 95.8% for unrestricted, 40%, and 20%-open cases. Hence the combustion stability can be improved with increased tumble intensity under part-load operating conditions, similar to the results by Omori et al [16]. can be improved with increased tumble intensity under partload operating conditions, similar to the observations by Omori et al [16].…”

Section: Figure 9 Comparison Of Flow Loss Coefficientsupporting

confidence: 88%

“…Hence the combustion stability can be improved with increased tumble intensity under part-load operating conditions, similar to the results by Omori et al [16]. can be improved with increased tumble intensity under partload operating conditions, similar to the observations by Omori et al [16].…”

Section: Figure 9 Comparison Of Flow Loss Coefficientsupporting

confidence: 88%

“…Experiments are usually performed on steady flow bench under a fixed air flow rate or bore pressure at each intake valve lift. Omori et al [16] conducted steady flow test under a differential bore pressure of 3.92 kPa for tumble and conventional inlet ports. They observed a strong correlation between tumble intensity and combustion stability.…”

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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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: Figure 9 Comparison Of Flow Loss Coefficientsupporting

confidence: 88%

Section: Figure 9 Comparison Of Flow Loss Coefficientsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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 compression ratio was not reported. The tumbling ratio (TVR≈2.0) was calculated according to the procedure reported by Omori et al in 1991 [30]. Kiyota demonstrated the concept of lean combustion by Barrel-Stratification using the inherent characteristics of twin intake porting arrangements.…”

Section: Literature Reviewmentioning

confidence: 99%

Barrel Swirl Behaviour in a Four-Valve Engine with Pentroof Chamber

Newman

Girgis

Benjamin

et al. 1995

SAE Technical Paper Series

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“…Instead of shrouded valves, the tumbling motion can be achieved by using directed ports [7]. It was shown [8][9][10] that with the appearance of the tumbling vortex in modern multivalve engines the burning rate is sped up while emissions are reduced. In addition, the lean burn limit is extended.…”

Section: Introductionmentioning

confidence: 98%

Tumbling/Squish Interaction in Loop-Scavenged Two-Stroke Engines

Tsui

Cheng

1997

Numerical Heat Transfer, Part A: Applications

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This anide describes a numerical investigation of the flow in a loop-scavenged two-stroke engine equipped with a head-bowl combustion chamber. The bowl is either plautl in the center of the cylinder head or displaced away from the center. A1Iention is focused on the period of compression and early expansion. Resulss show that the effects of compression of the tumbling vortex by the piston become prominent after the midcompression slage, resulting in significant cascading of energy from mean flow to turbulence, followed by a fast decay ofturbaJence. The subsequent emergence ofsquish and reverse squish helps retard the decay. As a consequence, the cases with head bowls possess higher levels of mean flow and turbulence than those withoul bowls at top dead center and the later slage. It is also shawn in the resu/ls that the offset of the head bowt has signifICant effects on the mean flow and turbulence characteristics, highly dependent on the offset direction.

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Effect of Intake Port Flow Pattern on the In-Cylinder Tumbling Air Flow in Multi-Valve SI Engines

Cited by 53 publications

References 4 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

Barrel Swirl Behaviour in a Four-Valve Engine with Pentroof Chamber

Tumbling/Squish Interaction in Loop-Scavenged Two-Stroke Engines

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