Effects of EGR on combustion process of DI diesel engine during cold start

Abstract

Experiments on the effects of external and internal exhaust gas recirculation (EGR) on combustion and emission performance during a cold start process were investigated in a 135 single-cylinder DI diesel engine. Combustion was improved during the initial ignition cycles by introducing internal or external EGR. The addition of an appropriate amount of internal or external EGR can promote the combustion stability significantly. However, excessive amounts of external EGR could lead to extremely unstable combustion or even misfiring. An appropriate amount of internal or external EGR decreased smoke opacity effectively during a cold start. External EGR reduced NO_x emissions effectively while internal EGR led to an increase in NO_x emissions due to thermal effects.

References

1. Liu Hengqing HeneinN A Bryzik W Simulation of diesel engines cold-startSAE Paper 2003-01-0080 2003
2. Han Zhiping Henein N Nitu B et al.Diesel engine cold start combustion instabilityand control strategySAE Paper 2001-01-1237 2001
3. Bielaczyc P Merkisz J Pielecha J Investigation of exhaust emissions from DI diesel engineduring cold and warm startSAE Paper 2001-01-1260 2001
4. Bielaczyc P Merkisz J Pielecha J A method of reducing the exhaust emissions from DI dieselengines by the introduction of a fuel cut off system during cold startSAE Paper 2001-01-3283 2001
5. Bielaczye P Merkisz J Cold-start emissions investigationat different ambient temperature conditionsSAE Paper 98042 1998
6. Shen K Matthews R D Chiu J P et al.Initial study of rail-plugs as an aid for cold startingof dieselsSAE Paper 940108 1994
7. Su Yan Liu Zhongchang Zhu Changji Analysis of direct injection diesel engine combustion duringstartJournal of Combustion Science andTechnology 2006 12(2)126130 (in Chinese)
8. Li Detao Foundational Research and Promoted Measures for Cold Start of DieselEngineBeijingScience Press 1998 7285 (in Chinese)
9. Sun Ruonan Sweet E J Zurlo J R et al.Diesel engine cold starting with catalytically ignitedrecirculated exhaust gasSAE Paper 940086 1994
10. Lindl B Schmitz H - G Cold start equipment for dieseldirect injection enginesSAE Paper 1999-01-1244 1999
11. Osuka I Nishimura M Tanaka Y et al.Benefits of new fuel injection system technologyon cold startability of diesel engines―Improvement of coldstartability and white smoke reduction by means of multi injectionwith common rail fuel system (ECD-U2)SAEPaper 940586 1990
12. Zheng Ming Reader G T Hawley J G Diesel engine exhaust gas recirculation–A reviewon advanced and novel conceptsEnergy Conversionand Management 2004 45(6)883900. doi:10.1016/S0196‐8904(03)00194‐8
13. Liu Z Karim G A An examination of the roleof residual gases in the combustion processes of motored engines fuelledwith gaseous fuelsSAE Paper 961081 1996
14. Kwon S - I Arai M Hiroyasu H Ignition delay of a diesel spray injected into a residualgas mixture. SAE Paper 911841 1991