Experimental and numerical study of the behavior of three-way catalytic converters under different engine operation conditions

The thesis reports the studies on how the three-way catalytic converters behave under different operation conditions. The main focus of the work is in the oxygen storage capacity of the three-way catalyst. Rich-to-lean air/fuel ratio step-change experiments were carried out to quantify the oxygen storage capacity. Results show that the amount of oxygen stored is dependent on how much oxygen is present in the exhaust. Thus the oxygen storage capacity is not a fixed value, rather it is determined by the equilibrium between the storage sites and the feed stream. A numerical model was developed to characterize the oxygen storage capacity. The model matches well with the experiments. The effects of catalyst age and fuel sulfur content on oxygen storage were measured. The results show that the aging effects and fuel sulfur effects are decoupled. The storage capacity decreases by 10% for every 150ppm increase in fuel sulfur, and it scales with (age⁻⁰̇⁸⁴). Different modes of air/fuel ratio modulations were tested on the catalysts, since such modulation is the practice to keep conversion efficiency high and to increase robustness of the catalyst during transients.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Zhang, Yuetao

Advisor dc:contributor.advisor

• Wai K. Cheng.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33916

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33916