Real-World Engine Cold Start and "Restart" Particle Number Emissions from a 2010 Hybrid and Comparable Conventional Vehicle
Despite increasing popularity of hybrid-electric vehicles, few studies have compared their real-world particle emissions from internal combustion engine (ICE) cold starts and restarts, which have been shown to result in particulate number (PN) concentrations that exceed normal engine operations. Tailpipe PN concentrations emitted from a conventional and hybrid 2010 Toyota Camry were quantified during 1 Hz sampling over 44 replicate runs of a 32-mile route in Chittenden County, Vermont using the Total On-board Tailpipe Emissions Measurement System. This study is the first to compare hybrid and conventional vehicle cold start emissions as well as quantify PN concentrations arising from hybrid engine restarts under a range of real-world driving ambient temperature (-10 to 41 ˚C) and road grade (-9 to 12%) conditions. Cold start events averaged 9 seconds in duration, with total raw PN concentrations between 9.2E4 and 4.5E7 #/cm3. Hybrid engine restart events were characterized over 25 runs. The hybrid ICE was off 20% to 50% of the total run time, with corresponding ICE restarts ranging between 42 and 118 events per run. The number of restarts increased at higher ambient temperature, but the PN concentration range per individual restart event did not vary. The mean hybrid restart total PN concentration was 4 times lower than those of hybrid cold starts. Hybrid cold start PN concentrations were on average 10% lower than those the conventional vehicle. Over the entire route, the mean hybrid PN concentration was 4 times higher than the conventional PN concentration.
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Supplemental Notes:
- This paper was sponsored by TRB committee ADC20 Transportation and Air Quality
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Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- Conger, Matt
- Holmen, Britt A
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Conference:
- Transportation Research Board 91st Annual Meeting
- Location: Washington DC, United States
- Date: 2012-1-22 to 2012-1-26
- Date: 2012
Language
- English
Media Info
- Media Type: Digital/other
- Features: Figures; References; Tables;
- Pagination: 15p
- Monograph Title: TRB 91st Annual Meeting Compendium of Papers DVD
Subject/Index Terms
- TRT Terms: Air quality; Cold starts (Driving); Exhaust gases; Hybrid vehicles; Internal combustion engines; Particulates
- Subject Areas: Energy; Environment; Highways; Passenger Transportation; Vehicles and Equipment; I15: Environment; I91: Vehicle Design and Safety;
Filing Info
- Accession Number: 01367696
- Record Type: Publication
- Report/Paper Numbers: 12-4570
- Files: TRIS, TRB
- Created Date: Apr 11 2012 11:11AM