Turbulence characteristics of tumble flow in a four-valve engine

Kang, Kernyong; Baek, Je Hyun

doi:10.1016/s0894-1777(98)10023-7

Cited by 42 publications

(25 citation statements)

References 14 publications

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“…also found by [76] who used cycle-resolved analysis with a 12 °CA window averaging to obtain in-cycle mean flow and turbulence in a 4-valve pentroof engine of under square geometry with similar bore and compression ratio to that of the current study, imposing various levels of swirl by valve deactivation when the engine was operated at 1500 RPM with wide-open-throttle. Furthermore, the velocities and turbulence intensities of [76] were similar to those of the current investigation, unlike those of [66,67] where intensities close to TDC were only of the order of 0.2-0.5 m/s for a conventional and tumble port at 500 RPM and 1000 RPM. However, the low mean piston speed of only 1.6 m/s at 1000 RPM due to the short stroke of the over-square engine of [66,67] could largely account for the differences found.…”

Section: Frequency Analysissupporting

confidence: 83%

Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine

Aleiferis

Behringer

Malcolm

2016

Flow Turbulence Combust

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In-cylinder air flow structures are known to play a major role in mixture preparation and flame development in spark-ignition engines. In this paper both LDV and PIV measurements were undertaken in an optical spark-ignition at 1500 RPM, 0.5 bar inlet plenum pressure. One of the primary PIV planes was vertical, cutting through the centrally located spark plug (tumble plane) inside the pentroof at ignition timing. The other plane was horizontal inside the pentroof 1 mm below the spark plug. LDV was conducted 1 mm below the spark plug on a line from inlet to exhaust but also on a lower line 14 mm below the spark plug. In-cylinder PIV data at specific crank angles in the intake and compression strokes were also analysed on the central tumble plane and on a horizontal plane 14 mm below the spark plug. The combination of both techniques allowed high spatial and temporal resolution as the two data sets complemented each other to provide details of mean flow and turbulence characteristics on different levels, aiming ultimately for quantification of integral time scales and length scales. LDV cycle-resolved analysis distinguished between the classic approach of using the time integral of the autocorrelation function to obtain the integral time scale and a high-frequency cut-off analysis to obtain high-and low-frequency fluctuations about an in-cycle mean.3

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Section: Frequency Analysissupporting

confidence: 83%

Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine

Aleiferis

Behringer

Malcolm

2016

Flow Turbulence Combust

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“…Statistical analysis of in-cylinder flow velocities by both LDV and PIV methods in the engine under study showed u values of the order 3.0 m/s on the basis of typical ensemble averaging techniques that lead to 'mean' and 'RMS' values [54,55]. However, methods to distinguish in-cycle bulk velocities from high-frequency turbulence values were also applied to the LDV data of the current engine according to [71] and these led to u values of ~1.5 m/s [55]. The laminar burning velocities of [40,41] at 5 bar, 423 K were used as baseline, whilst all the other parameters were calculated for 5 bar, 500 K, the approximate pressure and temperature at ignition as obtained from the engine's pressure traces.…”

Section: Flame Speed and Roundnessmentioning

confidence: 99%

Flame front analysis of ethanol, butanol, iso-octane and gasoline in a spark-ignition engine using laser tomography and integral length scale measurements

Aleiferis

Behringer

2015

Combustion and Flame

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“…Various designs over the years have been introduced in internal combustion engines with the aim of improving its performance. They include the redesigning of its inlet manifold to enhance turbulence, the redesigning of the combustion chamber to increase swirl and tumble [3,4], positioning of the spark plugs for short flame travel and injectors for better fuel mixing etc [5]. All these design factors have all been geared towards improving combustion efficiency, engine power output and a reduction in the amount of expelled products of incomplete combustion [6].…”

Section: Introductionmentioning

confidence: 99%

Knock characteristics analysis of a supercharged spark Ignition engine using three grades of fuels

2017

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The power output of a spark ignition engine could be improved by boosting the intake pressure and compression ratio; however the applications of these are limited by knock in engines. This study examined the knocking behaviours of three commercially available fuels for spark ignition engines operated at engine intake pressures of 1.6 and 2.0 bar. The pressure data for the fuels tested were grouped into three: the fast cycle, medium cycle and slow cycles. Knock intensities from the pressure data were processed with Fast Fourier Transform (FFT) and band pass filtering techniques. The results showed that the knocking cycles occurred only in the fast and medium cycles. These results supported the view that auto-ignition of end-gases was due to compression from the high speed propagating flames. FTiR spectrums showed that the presence of aromatics was responsible for the better anti-knock quality exhibited by E5 and ULG 98 over PRF 95.

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Turbulence characteristics of tumble flow in a four-valve engine

Cited by 42 publications

References 14 publications

Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine

Integral Length Scales and Time Scales of Turbulence in an Optical Spark-Ignition Engine

Flame front analysis of ethanol, butanol, iso-octane and gasoline in a spark-ignition engine using laser tomography and integral length scale measurements

Knock characteristics analysis of a supercharged spark Ignition engine using three grades of fuels

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