Achieving Stable Engine Operation of Gasoline Compression Ignition Using 87 AKI Gasoline Down to Idle

Kolodziej, Christopher P.; Kodavasal, Janardhan; Ciatti, Stephen; Som, Sibendu; Shidore, Neeraj; Delhom, Jeremy

doi:10.4271/2015-01-0832

Cited by 78 publications

(34 citation statements)

References 51 publications

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“…Alternatively, one could increase injection pressure to improve mixing. 37 Figure 21 shows the evolution of CO as a function of CA in terms of EICO. The DI case shows a much higher EICO relative to the PFI case (14.44 g/kg fuel vs 2.04 g/kg fuel).…”

Section: No Emissionsmentioning

confidence: 99%

Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions

Kodavasal

Lavoie

Assanis

et al. 2016

International Journal of Engine Research

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Full-cycle computational fluid dynamics simulations with gasoline chemical kinetics were performed to determine the impact of breathing and fuel injection strategies on thermal and compositional stratification, combustion and emissions during homogeneous charge compression ignition combustion. The simulations examined positive valve overlap and negative valve overlap strategies, along with fueling by port fuel injection and direct injection. The resulting charge mass distributions were analyzed prior to ignition using ignition delay as a reactivity metric. The reactivity stratification arising from differences in the distributions of fuel-oxygen equivalence ratio (f FO), oxygen molar fraction (x O2) and temperature (T) was determined for three parametric studies. In the first study, the reactivity stratification and burn duration for positive valve overlap valve events with port fuel injection and early direct injection were nearly identical and were dominated by wall-driven thermal stratification. nitrogen oxide (NO) and carbon monoxide (CO) emissions were negligible for both injection strategies. In the second study, which examined negative valve overlap valve events with direct injection and port fuel injection, reactivity stratification increased for direct injection as the f FO and T distributions associated with direct fuel injection into the hot residual gas were positively correlated; however, the latent heat absorbed from the hot residual gas by the evaporating direct injection fuel jet reduced the overall thermal and reactivity stratification. These stratification effects were offsetting, resulting in similar reactivity stratification and burn durations for the two injection strategies. The higher local burned gas temperatures with direct injection resulted in an order of magnitude increase in NO, while incomplete combustion of locally over-lean regions led to a sevenfold increase in CO emissions compared to port fuel injection. The final study evaluated positive valve overlap and negative valve overlap valve events with direct injection. Relative to positive valve overlap, the negative valve overlap condition had a wider reactivity stratification, a longer burn duration and higher NO and CO emissions associated with reduced fuel-air mixing.

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Section: No Emissionsmentioning

confidence: 99%

Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions

Kodavasal

Lavoie

Assanis

et al. 2016

International Journal of Engine Research

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“…Since its narrow operating range limits the commercial viability of HCCI, a large number of alternative strategies have been introduced, including exhaust gas recirculation (EGR), 3–7 variable compression ratio (VCR), 8 and charge stratification. 9–24 EGR reduces the heat release rate by lowering the reactivity of the mixture. It has been shown that by changing the EGR rate the ignition timing and combustion duration can be varied.…”

Section: Introductionmentioning

confidence: 99%

“…Many researchers used other LTC modes to address the challenges of HCCI such as premixed charge compression ignition (PCCI), 9,12,20,23 gasoline compression ignition (GCI), 13,14,17 gasoline direct injection compression ignition (GDCI), 18 partial fuel stratification (PFS), 24 and reactivity-controlled compression ignition (RCCI). 15,16,19,22 These combustion modes mostly involve the use of charge stratification to control the heat release rate in LTC.…”

Section: Introductionmentioning

confidence: 99%

“…GCI and GDCI are also driven by charge stratification similarly to PCCI; however, these combustion modes utilize gasoline instead of diesel. 13,14,17,18 Compared to diesel, gasoline has a higher octane number which results in a longer ignition delay and therefore creates a more homogeneous mixture; however, it is more difficult to control the ignition timing and heat release rate of gasoline-fueled LTC engines. Using different timings and numbers of injections (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Computational fluid dynamics investigations of the effect of water injection timing on thermal stratification and heat release in thermally stratified compression ignition combustion

Boldaji

Sofianopoulos

Mamalis

et al. 2018

International Journal of Engine Research

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Advanced combustion concepts, like homogeneous charge compression ignition, are limited by their narrow operating range, which stems from a lack of control over the heat release process. This study explores a new advanced combustion mode, called thermally stratified compression ignition, which uses a direct water injection event to control the heat release process in low-temperature combustion. A three-dimensional computational fluid dynamics model coupled with detailed chemical kinetics is used to better understand the effects of direct water injection on thermal stratification in the cylinder and the resulting heat release process. Previous results showed that increasing the injection pressure results in a significantly broader temperature distribution due to increased evaporative cooling. In this way, direct water injection can control low-temperature combustion heat release and extend significantly the operable load range. In this study, simulations were performed over a range of start of injection timings in order to determine its effect on thermal stratification and heat release. The results show that for both low and high injection pressures advancing the start of water injection results in increased thermal stratification and reduced peak pressure and heat release rate for injections occurring after −60 °CAD. Before −60 °CAD, advancing the water injection has a varied effect on thermal stratification and heat release depending on the injection pressure and mass of the injected water.

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“…Many of the LTC strategies have attempted to use charge stratification to control the heat release process including Premixed Charge Compression Ignition (PCCI) [10][11][12], Gasoline Compression Ignition (GCI) [13][14][15], Gasoline Direct Injection Compression Ignition (GDCI) [16], Partial Fuel Stratification (PFS) [17], and even Reactivity Controlled Compression Ignition (RCCI) [18][19][20]. While these combustion modes have demonstrated success in terms of controllability and expanded operating range, the intentional mixture inhomogeneity has an inherent risk of elevated soot and NOx emissions.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Simulations of the Effect of Water Injection Characteristics on TSCI: A New, Load-Flexible, Advanced Combustion Concept

Boldaji

Sofianopoulos

Mamalis

et al. 2018

Journal of Engineering for Gas Turbines and Power

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Homogeneous charge compression ignition (HCCI) combustion has the potential for high efficiency with very low levels of NOx and soot emissions. However, HCCI has thus far only been achievable in a laboratory setting due the lack of control over the start and rate of combustion and its narrow operating range. In the present work, direct water injection (WI) was investigated to solve the aforementioned limitations of HCCI. This new advanced combustion mode is called thermally stratified compression ignition (TSCI). A three-dimensional computational fluid dynamics (3D CFD) model was developed using CONVERGE CFD coupled with detailed chemical kinetics to gain a better understanding of the underlying phenomena of the water injection event in a homogeneous, low temperature combustion (LTC) strategy. The CFD model was first validated against previously collected experimental data. The model was then used to simulate TSCI combustion and the results indicate that injecting water into the combustion chamber decreases the overall unburned gas temperature and increases the level of thermal stratification prior to ignition. The increased thermal stratification results in a decreased rate of combustion, thereby providing control over its rate. The results show that the peak pressure and gross heat release rate (HRR) decrease by 37.8% and 83.2%, respectively, when 6.7 mg of water were injected per cycle at a pressure of 160 bar. Finally, different spray patterns were simulated to observe their effect on the level of thermal stratification prior to ignition. The results show that the symmetric patterns with more nozzle holes were generally more effective at increasing thermal stratification.

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Achieving Stable Engine Operation of Gasoline Compression Ignition Using 87 AKI Gasoline Down to Idle

Cited by 78 publications

References 51 publications

Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions

Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions

Computational fluid dynamics investigations of the effect of water injection timing on thermal stratification and heat release in thermally stratified compression ignition combustion

Computational Fluid Dynamics Simulations of the Effect of Water Injection Characteristics on TSCI: A New, Load-Flexible, Advanced Combustion Concept

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