Numerical Prediction of CCV in a PFI Engine using a Parallel LES Approach
Abstract
Cycletocycle variability (CCV) is detrimental to IC engine operation and can lead to partial burn, misfire, and knock. Predicting CCV numerically is extremely challenging due to two key reasons. Firstly, highfidelity methods such as large eddy simulation (LES) are required to accurately resolve the incylinder turbulent flowfield both spatially and temporally. Secondly, CCV is experienced over long timescales and hence the simulations need to be performed for hundreds of consecutive cycles. Ameen et al. (Int. J. Eng. Res., 2017) developed a parallel perturbation model (PPM) approach to dissociate this long timescale problem into several shorter timescale problems. The strategy is to perform multiple singlecycle simulations in parallel by effectively perturbing the initial velocity field based on the intensity of the incylinder turbulence. This strategy was demonstrated for motored engine and it was shown that the mean and variance of the incylinder flowfield was captured reasonably well by this approach. In the present study, this PPM approach is extended to simulate the CCV in a fired portfuel injected (PFI) SI engine. Two operating conditions are considered – a medium CCV operating case corresponding to 2500 rpm and 16 bar BMEP and a low CCV case corresponding to 4000 rpm and 12more »
 Authors:
 Publication Date:
 Research Org.:
 Argonne National Lab. (ANL), Argonne, IL (United States)
 Sponsoring Org.:
 USDOE Office of Energy Efficiency and Renewable Energy (EERE)  Office of Vehicle Technology; USDOE Office of Energy Efficiency and Renewable Energy (EERE)  Bioenergy Technologies Office (BETO)
 OSTI Identifier:
 1402082
 DOE Contract Number:
 AC0206CH11357
 Resource Type:
 Conference
 Resource Relation:
 Conference: 2017 ASME Internal Combustion Engine Fall Technical Conference, 10/15/17  10/18/17, Seattle, WA, US
 Country of Publication:
 United States
 Language:
 English
Citation Formats
Ameen, Muhsin M, Mirzaeian, Mohsen, Millo, Federico, and Som, Sibendu. Numerical Prediction of CCV in a PFI Engine using a Parallel LES Approach. United States: N. p., 2017.
Web.
Ameen, Muhsin M, Mirzaeian, Mohsen, Millo, Federico, & Som, Sibendu. Numerical Prediction of CCV in a PFI Engine using a Parallel LES Approach. United States.
Ameen, Muhsin M, Mirzaeian, Mohsen, Millo, Federico, and Som, Sibendu. 2017.
"Numerical Prediction of CCV in a PFI Engine using a Parallel LES Approach". United States.
doi:.
@article{osti_1402082,
title = {Numerical Prediction of CCV in a PFI Engine using a Parallel LES Approach},
author = {Ameen, Muhsin M and Mirzaeian, Mohsen and Millo, Federico and Som, Sibendu},
abstractNote = {Cycletocycle variability (CCV) is detrimental to IC engine operation and can lead to partial burn, misfire, and knock. Predicting CCV numerically is extremely challenging due to two key reasons. Firstly, highfidelity methods such as large eddy simulation (LES) are required to accurately resolve the incylinder turbulent flowfield both spatially and temporally. Secondly, CCV is experienced over long timescales and hence the simulations need to be performed for hundreds of consecutive cycles. Ameen et al. (Int. J. Eng. Res., 2017) developed a parallel perturbation model (PPM) approach to dissociate this long timescale problem into several shorter timescale problems. The strategy is to perform multiple singlecycle simulations in parallel by effectively perturbing the initial velocity field based on the intensity of the incylinder turbulence. This strategy was demonstrated for motored engine and it was shown that the mean and variance of the incylinder flowfield was captured reasonably well by this approach. In the present study, this PPM approach is extended to simulate the CCV in a fired portfuel injected (PFI) SI engine. Two operating conditions are considered – a medium CCV operating case corresponding to 2500 rpm and 16 bar BMEP and a low CCV case corresponding to 4000 rpm and 12 bar BMEP. The predictions from this approach are also shown to be similar to the consecutive LES cycles. Both the consecutive and PPM LES cycles are observed to underpredict the variability in the early stage of combustion. The parallel approach slightly underpredicts the cyclic variability at all stages of combustion as compared to the consecutive LES cycles. However, it is shown that the parallel approach is able to predict the coefficient of variation (COV) of the incylinder pressure and burn rate related parameters with sufficient accuracy, and is also able to predict the qualitative trends in CCV with changing operating conditions. The convergence of the statistics predicted by the PPM approach with respect to the number of consecutive cycles required for each parallel simulation is also investigated. It is shown that this new approach is able to give accurate predictions of the CCV in fired engines in less than onetenth of the time required for the conventional approach of simulating consecutive engine cycles.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

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