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The Effect of Ambient Temperature on Cold Start Urban Traffic Emissions for a Real World SI Car

Andrews, G.E., Zhu, G., Li, H., Simpson, A., Wylie, J.A., Bell, M. and Tate, J. (2004) The Effect of Ambient Temperature on Cold Start Urban Traffic Emissions for a Real World SI Car. In: SAE 2004 Powertrain & Fluid Systems, October 2004, Tampa, Florida, USA.

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The influence of ambient temperature on exhaust emissions for an instrumented Euro 1 SI car was determined. A real world test cycle was used, based on an urban drive cycle that was similar to the ECE urban drive cycle. It was based on four laps of a street circuit and an emissions sample bag was taken for each lap. The bag for the first lap was for the cold start emissions. An in-vehicle direct exhaust dual bag sampling technique was used to simultaneously collect exhaust samples upstream and downstream of the three-way catalyst (TWC). The cold start tests were conducted over a year, with ambient temperatures ranging from – 2°C to 32°C. The exhaust system was instrumented with thermocouples so that the catalyst light off temperature could be determined. The results showed that CO emissions for the cold start were reduced by a factor of 8 downstream of catalyst when ambient temperature rose from -2°C to 32°C, the corresponding hydrocarbon emissions were reduced by a factor of 4. There was no clear relationship between NOx emissions and ambient temperature. For subsequent laps of the test circuit the reduction of CO and HC emissions as a function of ambient temperature was lower. The time for catalyst light off increased by 50% as the ambient temperature was reduced. The results show that the vehicle used is unlikely to meet the new – 7oC cold start CO emission regulations.

Item Type: Conference or Workshop Item (Paper)
Copyright, Publisher and Additional Information: The following paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download the pdf file and print one copy of this SAE paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others. SAE Paper # 2004-01-2903 © 2004 SAE International.
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Environment (Leeds) > Institute for Transport Studies (Leeds)
Depositing User: Adrian May
Date Deposited: 22 Jun 2007
Last Modified: 05 Jun 2014 23:52
Status: Published
Refereed: Yes
URI: http://eprints.whiterose.ac.uk/id/eprint/2526

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