Modelling of ignition mechanisms and pollutant formation in direct-injection diesel engines with multiple injections

Abstract

Multiple injections are an important aspect in modern direct-injection diesel engine development. The representative interactive flamelet (RIF) model, which was successfully used previously for simulations of diesel engine combustion, was recently extended to model multiple injections. In this paper this new RIF model is applied to model ignition and combustion with a pilot and a main injection with various dwell times, start of injection timings, and loads. Special emphasis is placed on the ignition of the main injection. It is shown that, for the investigated cases, the main injection does not auto-ignite but it is ignited by a strained premixed flame that propagates from the pilot injection to the mixture field of the main injection. The structure of that flame and the influence of the scalar dissipation rate on the propagation speed are investigated in detail. In addition to pressure curves, modelling results for NO_x and soot emissions are compared with experimental data, showing good agreement.

Keywords

modelling ignition mechanisms multiple injections pollutant formation direct-injection diesel engines

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References

Bosch, AG Siegeszug von Dieselfahrzeugen in West-europa auch 2003 ungebremst - mit Einspritz-systemen von Bosch, PI 4392, 1 2004.

Verband der Automobilindustrie, Marktgewichteter Kraftstoffverbrauch von Pkw/Kombi aus deutscher Produktion http://www.vda.de/de/aktuell/kraftstoffverbrauch/pdf/gewichtet.

United Nations Framework Convention on Climate Change, http://unfccc.int/text/resource/convkp.html.

Shundoh

Komori

Tsujimur

Kobayashi

NO_x reduction from diesel combustion using pilot injection with high pressure fuel injection

SAE paper 920461, 1992.

Nehmer

D. A.

Reitz

R. D.

Measurement of the effect of injection rate and split injections on diesel engine soot and NO_x emissions

SAE paper 940668, 1994.

Pierpont

D. A.

Montgomery

D. T.

Reitz

R. D.

Reducing particulate and NO_x emissions by using multiple injections and EGR in a DI diesel engine

SAE paper 950217, 1995.

Tow

Pierpont

Reitz

R. D.

Reducing particulates and NO_x emissions by using multiple injections in a heavy duty DI diesel engine

SAE paper 940897, 1994.

Han

Uludogan

Hampson

G. J.

Reitz

R. D.

Mechanism of soot and NO_x emission reduction using multiple-injections in a diesel engine

SAE paper 960633, 1996.

Montgomery

D. T.

Reitz

R. D.

Six-mode cycle evaluation of the effect of EGR and multiple injections on particulate and emissions from a DI diesel engine

SAE paper 960316, 1996.

10.

Amsden

A. A.

O'Rourke

P. J.

Butler

T. D.

KIVA II: A computer program for chemically reactive flows with sprays. Technical Report LA-11560-MS, Los Alamos National Laboratory, Los Alamos, New Mexico, USA, 1989.

11.

Amsden

A. A.

KIVA-3: A KIVA program with block-structured mesh for complex geometries. Technical Report LA-12503-MS, Los Alamos National Laboratory, Los Alamos, New Mexico, USA, 1993.

12.

Amsden

A. A.

KIVA-3V: A KIVA program for engines with vertical or canted valves. Technical Report LA-13313-MS, Los Alamos National Laboratory, Los Alamos, New Mexico, USA, 1997.

13.

Amsden

A. A.

KIVA-3V, release 2: Improvements to KIVA-3V. Technical Report LA-UR-99-915, Los Alamos National Laboratory, Los Alamos, New Mexico, USA, 1999.

14.

Barths

Simulation of diesel engine and gas turbine combustion using multiple flamelets with detailed chemistry. PhD thesis, Rheinisch-Westfälische Tech-nische Hochschule Aachen, Germany, 2001.

15.

Leipertz

Abschlubericht zum Groprojekt der Bayerischen Forschungsstiftung: Potential neuartiger Einspritzverfahren zur Reduzierung von Ru und NO_x bei der dieselmotorischen Verbrennung. Technical Report, Lehrstuhl für Technische Thermo-dynamik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany.

16.

Antoni

Untersuchung des Verbrennungsvorgangs im direkteinspritzenden Diesel-motor zyklusaufgel-öster Emissionsspektroskopie. PhD thesis, Rheinisch-Westfälische Technische Hochschule Aachen, Germany, 1998.

17.

Magnusson

Final publishable report from the D-Level project (GRD1-1999-10681). Technical Report. European Commission, 2003.

18.

Williams

F. A.

Combustion Theory, 1985 (Benjamin-Cummins, Menlo Park, California).

19.

Carlucci

Ficarella

Laforgia

Effects of pilot injection parameters on combustion for common rail diesel engines

SAE paper 2003-01-0700, 2003.

20.

Alkidas

A. C.

Relationships between smoke measurements and particulate emissions

SAE paper 840412, 1984.

21.

Montgomery

D. T.

Reitz

R. D.

Effects of multiple injections and flexible control of boost and EGR on NO_x emissions and fuel consumption of a heavy-duty diesel engine

SAE paper 2001-01-0195, 2001.

22.

Hasse

Barths

Peters

Modeling the effect of split injections in diesel engines using representative interactive flamelets

SAE paper 1999-01-3547, 1999.

23.

Hergart

C.-A.

Barths

Peters

Modeling the combustion in a small-bore diesel engine using a method based on representative interactive flamelets

SAE paper 1999-01-3550, 1999.

24.

Dodd

A. E.

Holubecki

The measurement of diesel exhaust smoke. Technical Report 1965/10, Motor Industry Research Association, Nuneaton, Warwickshire, 1965.

25.

Hergart

C.-A.

Barths

Peters

Using representative interactive flamelets in the three-dimensional modeling of diesel combustion including the effect of heat tranfer. In Proceedings of the Tenth International Multidimensional Engine Modeling User's Group Meeting, 2000 (Cray Research Inc., Seattle, Washington).

26.

Weber

Peters

Bockhorn

Pittermann

Numerical simulation of the evolution of the soot particle size distribution in a DI diesel engine using an emulsified fuel of diesel-water

SAE paper 2004-01-1884, 2004.

27.

Hasse

Peters

A two mixture fraction flamelet model applied to split injections in a DI diesel engine

Proc. Combust. Inst. 2004, 30(2), 2755–2762.

28.

Peters

Laminar diffusion flamelet models in non-premixed turbulent combustion

Prog. Energy Combust. Sci. 1984, 10, 319–339.

29.

Peters

Rogg

Reduced kinetic mechanisms for applications in combustion systems. In Lecture Notes in Physics, Vol. 15 (Eds Peters

Rogg

), 1993 (Springer-Verlag, Berlin).

30.

Barths

Hasse

Peters

CFD modelling of non-premixed combustion in DI diesel engines

Int. J. Engine Res. 2000, 1(3), 249–267.

31.

O'Rourke

P. J.

The KIVA computer program for multidimensional chemically reactive fluid flows with fuel sprays. Technical Report LA-UR-85-1728, Los Alamos National Laboratory, Los Alamos, New Mexico, USA, 1985.

32.

AVL-VA, Forschungsbericht 8404, section 1.3. Technical Report, AVL, Graz, Austria.

33.

Uludogan

Xin

Reitz

R. D.

Exploring the use of multiple injectors and split injections to reduce DI diesel engine emissions

SAE paper 962058, 1996.

34.

Chan

Das

Reitz

R. D.

Modeling multiple injection and EGR effects on diesel engine emissions

SAE paper 972864, 1997.

35.

Chen

S. K.

Simultaneous reduction of NO_x and particulate emissions by using multiple injections in a small diesel engine

SAE paper 2000-01-3084, 2000.

36.

Peters

Wiliams

F. A.

The asymptotic structure of stoichiometric methane-air flames

Combust. Flame 1987, 68, 185–207.

37.

Peters

Turbulent Combustion, 2000 (Cambridge University Press, Cambridge).

38.

Pitsch

Modellierung der Zündung und Schad-stoffbildung bei der dieselmotorischen Verbrennung mit Hilfe eines interaktiven Flamelet-Modells. PhD thesis, Rheinisch-Westfälische Technische Hochschule Aachen, Germany, 1997.

39.

Girimaji

S. S.

Assumed ß-PDF model for turbulent mixing: Validation and extension to multiple scalar mixing. Combust. Sci. Technol., 18, 1991, 177–196.

40.

Muntean

G. G.

A theoretical model for the correlation of smoke number to dry particulate concentration in diesel exhaust

SAE paper 1999-01-0515, 1999.

41.

AVL Gerätehandbuch AVL 415 Rauchwertmeßgerät, Variable Sampling Smoke Meter (AVL, Graz, Austria).