CPL - Chalmers Publication Library
| Utbildning | Forskning | Styrkeområden | Om Chalmers | In English In English Ej inloggad.

Reduction of Fuel Consumption and Engine-out NOx Emissions in a Lean Homogeneous GDI Combustion System, Utilizing Valve Timing and an Advanced Ignition System

Gerben Doornbos (Institutionen för tillämpad mekanik, Förbränning) ; Stina Hemdal (Institutionen för tillämpad mekanik, Förbränning) ; D. Dahl
SAE Technical Papers: SAE 2015 World Congress and Exhibition; Cobo CenterDetroit; United States; 21 April 2015 through 23 April 2015 Vol. 2015-April (2015), April,
[Konferensbidrag, refereegranskat]

This study investigated how the amount of dilution applied can be extended while maintaining normal engine operation in a GDI engine. Adding exhaust gases or air to a stoichiometric air/fuel mixture yields several advantages regarding fuel consumption and engine out emissions. The aim of this paper is to reduce fuel consumption by means of diluted combustion, an advanced ignition system and adjusted valve timing. Tests were performed on a Volvo four-cylinder engine equipped with a dual coil ignition system. This system made it possible to extend the ignition duration and current. Furthermore, a sweep was performed in valve timing and type of dilution, i.e., air or exhaust gases. While maintaining a CoV in IMEP < 5%, the DCI system was able to extend the maximum lambda value by 0.1 - 0.15. Minimizing valve overlap increased lambda by an additional 0.1. For dilution by exhaust gases, an increase of 9% was noted for the ignition system and a further increase of 9% was obtained by minimizing the valve overlap at 1500 rpm/5.00 bar BMEP. This exchange of internal combustion residuals for external dilution resulted in a further decrease of fuel consumption but increased engine out NOx. Using air as a diluter resulted in a 6% fuel consumption benefit over exhaust gas dilution, mainly due to the enhanced combustion efficiency arising from higher oxygen concentrations. However, the lower oxygen concentration when using exhaust gases as a diluter led to 50% lower engine out NOx levels at the dilution limit.



Denna post skapades 2015-08-27.
CPL Pubid: 221294

 

Läs direkt!


Länk till annan sajt (kan kräva inloggning)


Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Förbränning

Ämnesområden

Energiteknik
Kemiska processer

Chalmers infrastruktur