This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Studying HCCI Combustion and its Cyclic Variations Versus Heat Transfer, Mixing and Discretization using a PDF Based Approach
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 20, 2009 by SAE International in United States
Annotation ability available
The ability to predict cyclic variations is certainly useful in studying engine operating regimes, especially under unstable operating conditions where one single cycle may differ from another substantially and a single simulation may give rather misleading results. PDF based models such as Stochastic Reactor Models (SRM) are able to model cyclic variations, but these may be overpredicted if discretization is too coarse.
The range of cyclic variations and the dependence of the ability to correctly assess their mean values on the number of cycles simulated were investigated. In most cases, the average values were assessed correctly on the basis of as few as 10 cycles, but assessing the complete range of cyclic variations could require a greater number of cycles. In studying average values, variations due too coarse discretization being employed are smaller than variations originating from changes in physical parameters, such as heat transfer and mixing parameters. Thus it feels safe to conclude that, even with such coarse discretization and fast execution, the findings obtained with use of the SRM are fundamentally correct. For studies of cyclic variations in engines, discretization needs to have a higher level of resolution to provide trustworthy results.
In the case of high levels of turbulence and evenly distributed heat transfer, the in-cylinder conditions become homogeneous more quickly. The results indicate that in HCCI engines inhomogeneties tend to promote earlier ignition and more stable operating conditions as well as lesser cyclic variations. The pressure rate was shown to generally increase under homogeneous conditions, which could lead to unwanted noise and even to engine damage. According to calculations for HCCI engines, the level of turbulence and the heat transfer distribution had little impact on the duration of combustion or on the amount of HC and NO at EVO, except for HC which rocketed in the odd misfiring cycles.
CitationTunér, M., Karlsson, M., and Mauss, F., "Studying HCCI Combustion and its Cyclic Variations Versus Heat Transfer, Mixing and Discretization using a PDF Based Approach," SAE Technical Paper 2009-01-0667, 2009, https://doi.org/10.4271/2009-01-0667.
Homogeneous Charge Compression Ignition Engines, 2009
Number: SP-2242 ; Published: 2009-04-20
Number: SP-2242 ; Published: 2009-04-20
- Heywood J. B., Internal Combustion Engine Fundamentals, McGraw Hill, New York, 1988.
- Montorsi L., Mauss F., Bianchi G. M., Bhave A. and Kraft M., 2003, Analysis of the HCCI Combustion of a Turbocharged Truck Engine Using a Stochastic Reactor Model, ASME ICE Division, ICES-2003-681.
- Amnéus P., Tunér M., Mauss F., Collin R., Nygren J., Richter M., Aldén M., Kraft M., Bhave A., Hildingsson L., Johansson B., Formaldehyde and Hydroxyl Radicals in an HCCI Engine -Calculations and LIF-Measurements, SAE 2007-01-0049.
- Gogan A., Lehtiniemi H., Sundén B. and Mauss F., Stochastic Model for the Investigation of the Effect of Turbulent Mixing on Engine Knock, SAE 2004-01-2999.
- Tunér M., Blurock E. S., Mauss F., “Phase Optimized Skeleton Mechanisms for Stochastic Reactor Models for Engine Simulation”, SAE 2005-01-3813.
- Samuelsson K., Gogan A., Netzell K., Lehtiniemi H., Sunden B., Mauss F., Modeling Diesel Engine Combustion and Pollutant Formation Using a Stochastic Reactor Model Approach, Intl. Conf. Clean Diesel Combustion, Lund, 2005.
- Tunér M., Pasternak M., Mauss F., Bensler H., A PDF-Based Model for Full Cycle Simulation of Direct Injected Engines, SAE 2008-01-1606.
- Frisch U., Turbulence: The Legacy of Kolmogorov A. N.. Cambridge University Press, 1995.
- Kraft M., Stochastic Modelling of Turbulent Reacting Flow in Chemical Engineering, 1998, Reihe 6 (391), pp. 1-109 (VDI Verlag, Fortschrittsberichte des VDI).
- Boulanger J., Liu F., Neill W. S., Smallwood G. J., Investigating renewable fuel combustion II: DNS of DME and n-heptane ignition in a turbulent non-homogeneous flow with high dissipation. International Journal of Environmental Studies, 64:4, pp 419-432, 2007.
- Curl R. L., Dispersed Phase Mixing: I. Theory and Effects in Simple Reactors, A.I.Ch.E. Journal, Vol. 9, No. 2, pp. 175-181, 1963.
- Janicka J., Kolbe W., Kollmann W., Closure of the transport equation for the probability density function of turbulent scalar fields. Journal of Non-Equilibrium Thermodynamics, 4, pp. 47-66, 1979.
- Woschni G., A Universally Applicable Equation for the Instantaneous Heat Transfer Coefficient in the Internal Combustion Engine, SAE 670931
- Bhave A., Balthasar M., Kraft M., Mauss F., Analysis of a natural gas fuelled homogeneous charge compression ignition engine with exhaust gas recirculation using a stochastic reactor model, Int. J. Engine Res., 5(1): 93-103, 2004a.
- Ahmed S. S., Moréac G., Zeuch T. and Mauss F., Reduced Mechanism for the Oxidation of the Mixtures of n-Heptane and iso-Octane, Proceeding of the European Combustion Meeting “ECM 2005”, Louvain-La-Neuve, Belgium, April 3-6, Paper No. 40, 2005.