Modeling of injection-rate shaping in diesel engine combustion

In direct-injection diesel engines, control of fuel-air mixing is essential for the combustion and the reduction of hazardous emissions. Fuel injection-rate shaping is one of the measures used to control fuel-air mixing in the combustion chamber, which results in a specific temporal distribution of fuel for a given injection duration. In this thesis, the transient nature of the injection-rate shapes is investigated at one specific high-load point of a single-cylinder small-bore diesel engine. Special emphasis is given to the processes related to soot formation. Two types of injection rates are analyzed: top-hat- and boot-shaped. Numerical simulations are performed using the Representative Interactive Flamelet model with a detailed chemical kinetics. Soot emissions are predicted using a detailed chemistry based soot model. The results of this work present an in-depth comparison between the top-hat- and boot-shaped injection rate, and the comparison of three boot-shaped rates featuring different temporal distribution of the fuel in the combustion chamber over the injection duration. Additionally, two approaches modeling soot formation in diesel engines are presented, aiming to improve soot predictions. The results show a strong coupling between the heat release and the injection-rate shape at this load point. The best emission results are achieved with the boot-shaped injection rate. The analysis of soot formation and oxidation processes suggests that the in-cylinder soot history strongly depends upon the injection-rate shape. Based on this work, it can be stated that the temporal distribution of fuel for a given injection duration could be a dynamic control parameter in diesel engine combustion.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2010

Author dc:creator

• Luckhchoura, Vivak

Contributors dc:contributor

• Peters, Norbert

• info:eu-repo/classification/ddc/620
• Dieselmotor
• Flamelet-Modell
• Turbulente Verbrennung
• Ingenieurwissenschaften
• flamelet
• diesel engine
• injection rate shaping
• CFD
• turbulent combustion

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124648%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:63201