Numerical Optimization of a Light-Duty Compression Ignition Engine Fuelled With Low-Octane Gasoline

Adhikary, Bishwadipa Das; Ra, Youngchul; Reitz, Rolf D.; Ciatti, Stephen

doi:10.4271/2012-01-1336

Cited by 34 publications

(13 citation statements)

References 39 publications

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“…In addition, MFS strategies typically feature a fuel injection event near top dead center (TDC) of the compression stroke to trigger combustion. [29][30][31][32][33][34][35][36][37][38][39][40] Finally, HFS utilizes the highest level of fuel stratification and typically features no premixed fuel and direct injection(s) relatively close to TDC. HFS tends to utilize higher fuel injection pressure compared to PFS and MFS in order to get the fuel injection events completed before the autoignition event, as illustrated in Figure 4 by the bar height.…”

Section: Fuel Stratification Levels For Ltgcimentioning

confidence: 99%

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Dempsey

Curran

Wagner

2016

International Journal of Engine Research

136

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Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasoline has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this study, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities and challenges associated with the various fuel stratification levels.

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Section: Fuel Stratification Levels For Ltgcimentioning

confidence: 99%

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Dempsey

Curran

Wagner

2016

International Journal of Engine Research

136

View full text Add to dashboard Cite

show abstract

“…This combustion mode has been gaining increasing attention over the last decade due to its potential of achieving diesel-like thermal efficiencies with significantly reduced engine-out nitrogen oxides (NOx) and soot emissions. Recent studies [5,6,7,8,9,10,11,12,13,14,15,16,17,18] reported that GCI combustion occurs as a series of autoignition events with minor contributions from the flame fronts. This is usually achieved by controlling the autoignition timing by manipulating equivalence ratio stratification levels within the cylinder through late injection in the compression stroke, in contrast to homogeneous charge compression ignition (HCCI) [19,20,21,22] and premixed ignition [23,24] engines where the fuel and air are fully mixed prior to entering the combustion chamber.…”

Section: Introductionmentioning

confidence: 99%

Effects of In-Cylinder Mixing on Low Octane Gasoline Compression Ignition Combustion

Badra

Elwardany

Sim

et al. 2016

SAE Technical Paper Series

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Gasoline compression ignition (GCI) engines have been considered an attractive alternative to traditional spark ignition engines. Low octane gasoline fuel has been identified as a viable option for the GCI engine applications due to its longer ignition delay characteristics compared to diesel and in the volatility range of gasoline fuels. In this study, we have investigated the effect of different injection timings at part-load conditions using light naphtha stream in single cylinder engine experiments in the GCI combustion mode with injection pressure of 130 bar. A toluene primary reference fuel (TPRF) was used as a surrogate for the light naphtha in the engine simulations performed here. A physical surrogate based on the evaporation characteristics of the light naphtha has been developed and its properties have been implemented in the engine simulations. Full cycle GCI computational fluid dynamics (CFD) engine simulations have been successfully performed while changing the start of injection (SOI) timing from -50° to -11 ° CAD aTDC. The effect of SOI on mixing and combustion phasing was investigated using detailed equivalence ratio-temperature maps and ignition delay times. Both experimental and computational results consistently showed that an SOI of -30° CAD aTDC has the most advanced combustion phasing (CA50), with the highest NOx emission. The effects of the SOI on the fuel containment in the bowl of the piston, the ignition delay time, combustion rate and emissions have been carefully examined through the CFD calculations. It was found that the competition between the equivalence ratio and temperature is the controlling parameter in determining the combustion phasings.

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“…Since this early work, many research groups from Lund University [27][28][29][30][31][32], University of Cambridge [33], Argonne National Laboratory [34][35][36], University of Wisconsin Madison [37] and Delphi Corporation [38][39][40] have performed additional experimental and numerical investigations operating with PPC using different fuels in the octane range of gasoline and ethanol. Different injection strategies have been explored, with various EGR rates, boost pressures, intake temperatures and swirl ratios at different engine loads and speeds.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Multiple Injection Strategies for Gasoline PPC Operation in a Newly Designed 2-Stroke HSDI Compression Ignition Engine

Benajes

Lima

Tribotté

2015

SAE Int. J. Engines

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Partially Premixed Combustion (PPC) of fuels in the gasoline octane range has proven its potential to achieve simultaneous reduction in soot and NOX emissions, combined with high indicated efficiencies; while still retaining proper control over combustion phasing with the injection event, contrary to fully premixed strategies. However, gasoline fuels with high octane number as the commonly available for the public provide a challenge to ensure reliable ignition especially in the low load range, while fuel blends with lower octane numbers present problems for extending the ignition delay in the high load range and avoid the onset of knocking-like combustion. Thus, choosing an appropriate fuel and injection strategy is critical to solve these issues, assuring successful PPC operation in the full engine map.In this framework, the objective of the present investigation consists of evaluating the use of multiple injection strategies for achieving stable PPC operation, attaining low NOX and soot emissions together with high efficiencies. This research was carried out in a singlecylinder DOHC 2-stroke HSDI CI engine using 95 Research Octane Number (RON) gasoline fuel. Three different operating conditions in terms of indicated mean effective pressure (IMEP) and speed were investigated: 3.1 bar IMEP and 1250 rpm, 5.5 bar IMEP and 1500 rpm and 10.4 bar IMEP and 1500 rpm. Parametric variations of injection timings, at different rail pressures and different fuel split between injections were experimentally performed to analyze the effect of the injection strategy over the combustion process, exhaust emissions and efficiency levels.Experimental results confirm how using an appropriate injection strategy helps to achieve stable PPC operation in the selected operating conditions; with competitive combustion stability, lower NOX and soot levels, and moderate CO and HC emissions with combustion efficiency over 96%, compared to Conventional Diesel Combustion (CDC).Finally, a detailed analysis of the local cylinder conditions was performed by means of 3D-CFD simulations in order to provide guidelines for further optimization of the gasoline PPC concept, when using multiple injection strategies in the 2-stroke engine under development.

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Numerical Optimization of a Light-Duty Compression Ignition Engine Fuelled With Low-Octane Gasoline

Cited by 34 publications

References 39 publications

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Effects of In-Cylinder Mixing on Low Octane Gasoline Compression Ignition Combustion

Investigation on Multiple Injection Strategies for Gasoline PPC Operation in a Newly Designed 2-Stroke HSDI Compression Ignition Engine

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