Time-Resolved Emission Sampling in a Direct-Injection Engine

Hudak, E. B.; Ghandhi, J. B.

doi:10.4271/1999-01-3309

Cited by 4 publications

(9 citation statements)

References 15 publications

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“…Cycle resolved flame structures are most easily obtained by Mie scattering from seeding particles being added to the intake air and a laser sheet technique with a copper vapor laser [28,104]. Single images from individual cycles may be recorded by LIF of fluorescent HC molecules which happen to be present in the fuel [29], or more reliably, by LIF of oxygen-insensitive dopants e.g.…”

Section: Diagnosticsmentioning

confidence: 99%

Flow and Combustion in Reciprocating Engines

Arcoumanis¹,

Kamimoto²

2009

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Section: Diagnosticsmentioning

confidence: 99%

Flow and Combustion in Reciprocating Engines

Arcoumanis¹,

Kamimoto²

2009

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“…Hudak and Ghandhi (1999) found a significant production of HC during the exhaust period from an experiment on a two-stroke direct-injection engine. Time-resolved measurements were made of the gas composition by using a high-speed sampling valve at the exhaust port.…”

Section: -3-2 Piston Fuel Film Behavior and The Effect On Emissionsmentioning

confidence: 99%

“…The main causes of high HC emissions known today are the flame quenching at the lean outer boundaries of the stratified zones, and fuel wetting on the piston crown and cylinder walls [Hudak and Ghandhi, 1999;Casarella and Ghandhi, 1998;Stanglmaier and Matthews, 1999]. Almost all DISI engines developed until now have adopted the wall-guided spray delivery system.…”

Section: List Of Figuresmentioning

confidence: 99%

“…Thus, it was considered that these effects are as significant to the total HC emissions as the bulk flame quenching mechanism and the other mechanisms discussed [Casarella and Ghandhi, 1998] for direct-injection engines under highly stratified operation. [Hudak and Ghandhi, 1999].…”

Section: -3-2 Piston Fuel Film Behavior and The Effect On Emissionsmentioning

confidence: 99%

“…Significant fuel wetting on the piston top is unavoidable for these types of DISI engines. Recent research has shown that the fuel impinged to the piston crown does not evaporate completely before combustion, and can survive during or after the expansion stroke, and is exhausted as unburned and partial-burned HC [Hudak and Ghandhi, 1999;Alger et al, 2001;Stevens and Steeper, 2000].…”

Section: List Of Figuresmentioning

confidence: 99%

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Fuel Film Temperature and Thickness Measurements on the Piston Crown of a Direct-Injection Spark-Ignition Engine

Park¹,

Ghandhi²

2005

SAE Technical Paper Series

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The fuel film thickness and temperature on the piston crown of a direct-injection spark-ignition (DISI) engine were measured using a fiber-based laser induced fluorescence (LIF) method. The engine investigated employed a wall-guided swirl-type system using a high-pressure swirl injector impinging onto the piston crown. The fuel used was isooctane with a small amount of a fluorescent liquid dopant. The measured fluorescence intensity was transformed to the fuel film thickness by way of the equations based on photophysics and the fiber optic properties. However, the fluorescence of the fuel mixture showed a strong dependency on the fuel temperature and this information was needed in the fuel film thickness calculation. The fuel film temperature, which may differ from the piston surface temperature, was measured by using a fiber-based fluorescence thermometry method.Engine tests were performed for motored and fired conditions under the late injection stratified mode. The results of the fuel film temperature measurement showed that the mean fuel film temperature follows the piston surface temperature and the convection heat transfer from the compressed hot air directly affected the mean fuel film temperature during the compression and expansion stroke. The fuel film thickness measurement results showed that the boiling point of the liquid dopant should be much higher than that of the main fuel to ii meet the co-evaporation condition. The fuel film persisted during the expansion stroke and started to evaporate actively from the exhaust valve opening crank angle for both motored and fired conditions. The fuel film thickness from the fuel injection to just before the occurrence of pool fires was the same level for motored and fired engine conditions although the piston temperature was higher for the fired condition. The spark ignition and the main flame before the pool fires do not affect the fuel film thickness. The duration and thickness of the fuel film was strongly affected by the boiling point of the fuel. The fuel film evaporates quicker for a fuel having a lower boiling point.

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Visualization of late-cycle phenomena in a direct injection spark ignition engine

Strand

Rothamer

Ghandhi

2005

International Journal of Engine Research

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Planar laser-induced fluorescence measurements of 3-pentanone doped into the fuel and the hydroxyl (OH) radical were separately performed in a direct injection spark ignition engine operating unthrottled at 600 r/min with an overall fuel-air equivalence ratio W of 0.3. It was found that the premixed flame, identified by OH fluorescence, did not propagate fully to the outermost edge of the combustion chamber regardless of image timing. Further, late in the cycle after the heat release had completed, fuel fluorescence was identified at the combustion chamber periphery. The fuel concentration at these late times was found to be lean, with little fuel at W>0.5. These findings strongly suggest that the flame has quenched at the edge of the fuel cloud, confirming a long-held belief about stratified combustion. A series of additional experiments were performed to examine the factors controlling the observed quenching phenomenon. Changes in the end gas conditions resulting from advanced combustion phasing were not sufficient to alleviate the existence of late-cycle fuel fluorescence. Throttling the intake to 69 kPa while maintaining the same mass of fuel injected resulted in complete flame propagation in the investigated field of view, as evidenced by the OH fluorescence, and late-cycle fuel fluorescence was not present in the field of view. Time-resolved exhaust hydrocarbon concentration measurements were found to be lower at the throttled condition.

show abstract

Time-Resolved Emission Sampling in a Direct-Injection Engine

Cited by 4 publications

References 15 publications

Flow and Combustion in Reciprocating Engines

Flow and Combustion in Reciprocating Engines

Fuel Film Temperature and Thickness Measurements on the Piston Crown of a Direct-Injection Spark-Ignition Engine

Visualization of late-cycle phenomena in a direct injection spark ignition engine

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