Numerical investigation of PPCI combustion at low and high charge stratification levels

A. Maghbouli, T. Lucchini, G. D'Errico, M. Izadi Najafabadi, L.M.T. Somers

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

Partially premixed compression ignition combustion is one of the low temperature combustion techniques which is being actively investigated. This approach provides a significant reduction of both soot and NOx emissions. Comparing to the homogeneous charge compression ignition mode, PPCI combustion provides better control on ignition timing and noise reduction through air- fuel mixture stratification which lowers heat release rate com- pared to other advanced combustion modes. In this work, CFD simulations were conducted for a low and a high air-fuel mixture stratification cases on a light-duty optical engine operating in PPCI mode. Such conditions for PRF70 as fuel were experimentally achieved by injection timing and spray targeting at similar thermodynamic conditions. After validating the computed results of cylinder pressure, apparent heat release rate, and OH ∗ spatial distributions, differences in engine thermal load and mixture fraction distributions at first stage and second stage ignition were compared. Assuming similar second stage ignition timing which is provided by intake air heating, experimental and simulation results reveal that the time between first and second stage ignition shortens and combustion phases to the main stage ignition faster in the high stratification case. Using flame structure diagrams, this was attributed to availability of a larger range of mixture fractions with higher reactivity. Creating optimum air-fuel stratification then can be considered as a useful and additional controlling parameter for a PPCI engine combustion phasing and subsequent emission formation.
LanguageEnglish
Article number2017-01-0739
JournalSAE Technical Papers
Issue number2017-01-0739
DOIs
StatePublished - 28 Mar 2017

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Ignition
Engines
Air
Air intakes
Engine cylinders
Soot
Thermal load
Noise abatement
Spatial distribution
Computational fluid dynamics
Availability
Thermodynamics
Heating
Temperature

Cite this

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title = "Numerical investigation of PPCI combustion at low and high charge stratification levels",
abstract = "Partially premixed compression ignition combustion is one of the low temperature combustion techniques which is being actively investigated. This approach provides a significant reduction of both soot and NOx emissions. Comparing to the homogeneous charge compression ignition mode, PPCI combustion provides better control on ignition timing and noise reduction through air- fuel mixture stratification which lowers heat release rate com- pared to other advanced combustion modes. In this work, CFD simulations were conducted for a low and a high air-fuel mixture stratification cases on a light-duty optical engine operating in PPCI mode. Such conditions for PRF70 as fuel were experimentally achieved by injection timing and spray targeting at similar thermodynamic conditions. After validating the computed results of cylinder pressure, apparent heat release rate, and OH ∗ spatial distributions, differences in engine thermal load and mixture fraction distributions at first stage and second stage ignition were compared. Assuming similar second stage ignition timing which is provided by intake air heating, experimental and simulation results reveal that the time between first and second stage ignition shortens and combustion phases to the main stage ignition faster in the high stratification case. Using flame structure diagrams, this was attributed to availability of a larger range of mixture fractions with higher reactivity. Creating optimum air-fuel stratification then can be considered as a useful and additional controlling parameter for a PPCI engine combustion phasing and subsequent emission formation.",
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Numerical investigation of PPCI combustion at low and high charge stratification levels. / Maghbouli, A.; Lucchini, T.; D'Errico, G.; Izadi Najafabadi, M.; Somers, L.M.T.

In: SAE Technical Papers, No. 2017-01-0739, 2017-01-0739, 28.03.2017.

Research output: Contribution to journalArticleAcademicpeer-review

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AU - Maghbouli,A.

AU - Lucchini,T.

AU - D'Errico,G.

AU - Izadi Najafabadi,M.

AU - Somers,L.M.T.

PY - 2017/3/28

Y1 - 2017/3/28

N2 - Partially premixed compression ignition combustion is one of the low temperature combustion techniques which is being actively investigated. This approach provides a significant reduction of both soot and NOx emissions. Comparing to the homogeneous charge compression ignition mode, PPCI combustion provides better control on ignition timing and noise reduction through air- fuel mixture stratification which lowers heat release rate com- pared to other advanced combustion modes. In this work, CFD simulations were conducted for a low and a high air-fuel mixture stratification cases on a light-duty optical engine operating in PPCI mode. Such conditions for PRF70 as fuel were experimentally achieved by injection timing and spray targeting at similar thermodynamic conditions. After validating the computed results of cylinder pressure, apparent heat release rate, and OH ∗ spatial distributions, differences in engine thermal load and mixture fraction distributions at first stage and second stage ignition were compared. Assuming similar second stage ignition timing which is provided by intake air heating, experimental and simulation results reveal that the time between first and second stage ignition shortens and combustion phases to the main stage ignition faster in the high stratification case. Using flame structure diagrams, this was attributed to availability of a larger range of mixture fractions with higher reactivity. Creating optimum air-fuel stratification then can be considered as a useful and additional controlling parameter for a PPCI engine combustion phasing and subsequent emission formation.

AB - Partially premixed compression ignition combustion is one of the low temperature combustion techniques which is being actively investigated. This approach provides a significant reduction of both soot and NOx emissions. Comparing to the homogeneous charge compression ignition mode, PPCI combustion provides better control on ignition timing and noise reduction through air- fuel mixture stratification which lowers heat release rate com- pared to other advanced combustion modes. In this work, CFD simulations were conducted for a low and a high air-fuel mixture stratification cases on a light-duty optical engine operating in PPCI mode. Such conditions for PRF70 as fuel were experimentally achieved by injection timing and spray targeting at similar thermodynamic conditions. After validating the computed results of cylinder pressure, apparent heat release rate, and OH ∗ spatial distributions, differences in engine thermal load and mixture fraction distributions at first stage and second stage ignition were compared. Assuming similar second stage ignition timing which is provided by intake air heating, experimental and simulation results reveal that the time between first and second stage ignition shortens and combustion phases to the main stage ignition faster in the high stratification case. Using flame structure diagrams, this was attributed to availability of a larger range of mixture fractions with higher reactivity. Creating optimum air-fuel stratification then can be considered as a useful and additional controlling parameter for a PPCI engine combustion phasing and subsequent emission formation.

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