A combustion kinetic model for estimating diesel engine NO x emissions

A phenomenological combustion model, which considers the space and time evolutions of a reacting diesel fuel jet, has been developed in order to estimate the instantaneous NO x concentration in a diesel engine cylinder from the start of the injection until the exhaust valve opening. The total injected fuel mass has been divided into different fuel packages, through the fuel injection rate file, to take into account the heterogeneous nature of the diesel combustion process. Owing to the importance of the kinetics on the formation and destruction mechanisms of the main pollutant species and radicals, the instantaneous composition of each fuel package has been calculated by using a chemical reaction mechanism which considers 27 species and 59 reactions. The main input data are those resulting from the application of the combustion diagnostic procedure to the instantaneous cylinder pressure signal obtained during the engine tests, such as the heat release law (HRL) and the mean temperature. A single-cylinder diesel engine was tested to validate the model and to analyse the influence of the injection parameters (injection pressure, injection timing and injected fuel mass) on the NO x emissions. A good agreement between the theoretical results and the experimental ones was found when the engine conditions were modified. The model proposed also allows a better knowledge of the local mixing fuel/air processes, which represent one of the most important uncertainties when modelling diesel combustion.

[1]  S. Turns.  Understanding NOx formation in nonpremixed flames: Experiments and modeling , 1995 .

[2]  G. Patnaik,et al.  Universal relationships in sooting methane-air diffusion flames , 1998 .

[3]  Shinji Kobayashi,et al.  The Effect of Injection Parameters and Swirl on Diesel Combustion with High Pressure Fuel Injection , 1991 .

[4]  Rolf Egnell,et al.  Combustion Diagnostics by Means of Multizone Heat Release Analysis and NO Calculation , 1998 .

[5]  J. Abraham,et al.  An Investigation of the Dependence of NO and Soot Formation and Oxidation in Transient Combusting Jets on Injection and Chamber Conditions , 2000 .

[6]  Takayuki Ito,et al.  Extraction of the suppression effects of oxygenated fuels on soot formation using a detailed chemical kinetic model , 2001 .

[7]  Vicente Bermúdez,et al.  Sensitivity of diesel engine thermodynamic cycle calculation to measurement errors and estimated parameters , 2000 .

[8]  John Abraham,et al.  Three-Dimensional Modeling of Soot and NO in a Direct-injection Diesel Engine , 1995 .

[9]  David B. Kittelson,et al.  NO2 formation in a diesel engine , 1991 .

[10]  H Salem,et al.  Prediction of the effect of injection parameters on NO x emission and burning quality in the direct injection diesel engine using a modified multizone model , 1998 .

[11]  J. Kramlich,et al.  Nitrous oxide behavior in the atmosphere, and in combustion and industrial systems , 1994 .

[12]  M. Frenklach,et al.  The oxidation of methane at elevated pressures: Experiments and modeling , 1994 .

[13]  Kazutoshi Mori,et al.  Application of Common Rail Fuel Injection System to a Heavy Duty Diesel Engine , 1994 .

[14]  R. J. B. Way,et al.  Methods for Determination of Composition and Thermodynamic Properties of Combustion Products for Internal Combustion Engine Calculations , 1976 .

[15]  Michael J. Pilling,et al.  Summary table of evaluated kinetic data for combustion modeling: Supplement 1 , 1994 .

[16]  James A. Miller,et al.  Kinetic modeling of hydrocarbon/nitric oxide interactions in a flow reactor , 1998 .

[17]  Charles E. Newman,et al.  A super-extended zel'dovich mechanism for nox modeling and engine calibration , 1998 .

[18]  S. Turns.  An Introduction to Combustion: Concepts and Applications , 2000 .

[19]  R. Reitz,et al.  Studying the roles of kinetics and turbulence in the simulation of diesel combustion by means of an extended characteristic time model , 1999 .

[20]  G. C. Quartucy,et al.  Implementing NOx control: Research to application , 1997 .

[21]  Octavio Armas,et al.  Kinetic Modelling of Gaseous Emissions in a Diesel Engine , 2000 .

[22]  Multizone Model for DI Diesel Engine Combustion and Emissions , 1999 .

[23]  Dimitrios T. Hountalas,et al.  DEVELOPMENT AND VALIDATION OF A 3-D MULTI-ZONE COMBUSTION MODEL FOR THE PREDICTION OF DI DIESEL ENGINES PERFORMANCE AND POLLUTANTS EMISSIONS , 1998 .

[24]  S. Chan,et al.  Prediction of transient nitric oxide in diesel exhaust , 1999 .

[25]  O. Armas,et al.  Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas , 1999 .

[26]  Bi Xiaoping,et al.  A Multi-Zone Model for Prediction of DI Diesel Engine Combustion and Soot Emission , 1994 .

[27]  Gary L. Borman,et al.  A COMPUTER PROGRAM FOR CALCULATING PROPERTIES OF EQUILIBRIUM COMBUSTION PRODUCTS WITH SOME APPLICATIONS TO I.C. ENGINES , 1975 .

[28]  Takeyuki Kamimoto,et al.  Combustion processes in diesel engines , 1991 .

[29]  J Wu,et al.  A direct injection diesel combustion model for use in transient condition analysis , 2001 .

[30]  James C. Keck,et al.  Rate-controlled partial-equilibrium method for treating reacting gas mixtures , 1971 .

[31]  C. Bowman.  Kinetics of pollutant formation and destruction in combustion , 1975 .

[32]  A. Hayhurst,et al.  Emissions of nitrous oxide from combustion sources , 1992 .

[33]  Octavio Armas Vergel.  Diagnóstico experimental del proceso de combustión en motores diesel de inyección directa , 1999 .

[34]  M. Harasek,et al.  NOx formation in natural gas combustion—a new simplified reaction scheme for CFD calculations , 2006 .

[35]  L. Caretto.  Mathematical modeling of pollutant formation , 1976 .

[36]  E. M. Bulewicz.  Combustion , 1964, Nature.

[37]  Rolf Egnell.  A Simple Approach to Studying the Relation between Fuel Rate Heat Release Rate and NO Formation in Diesel Engines , 1999 .

[38]  S. M. Shahed,et al.  Effects of Injection Timing and Exhaust Gas Recirculation on Emissions from a D.I. Diesel Engine , 1981 .

[39]  James A. Miller,et al.  Mechanism and modeling of nitrogen chemistry in combustion , 1989 .

[40]  F. P. Ricou,et al.  Measurements of entrainment by axisymmetrical turbulent jets , 1961, Journal of Fluid Mechanics.

[41]  Jose J. Lopez,et al.  Development of a zero-dimensional Diesel combustion model. Part 1: Analysis of the quasi-steady diffusion combustion phase , 2003 .

[42]  Dennis N. Assanis,et al.  Multi-Dimensional Modeling of Ignition, Combustion and Nitric Oxide Formation in Direct Injection Natural Gas Engines , 2000 .

[43]  Dennis N. Assanis,et al.  Multi-Zone DI Diesel Spray Combustion Model for Cycle Simulation Studies of Engine Performance and Emissions , 2001 .

[44]  Jose J. Lopez,et al.  Development of a zero-dimensional Diesel combustion model: Part 2: Analysis of the transient initial and final diffusion combustion phases , 2003 .

[45]  Mário Costa,et al.  The formation and destruction of NO in turbulent propane diffusion flames , 1998 .

[46]  Octavio Armas,et al.  Effect of the injection parameters of a common rail injection system on diesel combustion through thermodynamic diagnosis , 1999 .

[47]  J. Dec.  A Conceptual Model of DI Diesel Combustion Based on Laser-Sheet Imaging* , 1997 .

[48]  J. Heywood,et al.  Experimental and Theoretical Study of Nitric Oxide Formation in Internal Combustion Engines , 1970 .

[49]  Robert J. Santoro,et al.  Modeling and measurements of soot and species in a laminar diffusion flame , 1996 .

[50]  C. Westbrook,et al.  Diesel combustion: an integrated view combining laser diagnostics, chemical kinetics, and empirical validation , 1999 .

[51]  Z. Bazari,et al.  A DI diesel combustion and emission predictive capability for use in cycle simulation , 1992 .

[52]  J. Tomeczek,et al.  The Role of Nitrous Oxide in the Mechanism of Thermal Nitric Oxide Formation within Flame Temperature Range , 1997 .