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Title: Characterization of GDI PM during Vehicle Start-Stop Operation

Abstract

As the fuel economy regulations increase in stringency, many manufacturers are implementing start-stop operation to enhance vehicle fuel economy. During start-stop operation, the engine shuts off when the vehicle is stationary for more than a few seconds. When the brake is released by the driver, the engine restarts. Depending on traffic conditions, start-stop operation can result in fuel savings from a few percent to close to 10%. Gasoline direct injection (GDI) engines are also increasingly available on light-duty vehicles. While GDI engines offer fuel economy advantages over port fuel injected (PFI) engines, they also tend to have higher PM emissions, particularly during start-up transients. Thus, there is interest in evaluating the effect of start-stop operation on PM emissions. In this study, a 2.5L GDI vehicle was operated over the FTP75 drive cycle. Runs containing cold starts (FTP-75 cycle Phases 1 & 2) and multiple runs containing hot starts (FTP-75 cycle Phases 3 & 4) were performed each day. Note that the FTP-75 Phases 3 & 4 are identical to Phases 1 & 2 except that the engine is warmed up. Three fuels were evaluated: an 87 AKI gasoline (E0), a 21% splash blend of ethanol and the 87 AKI gasolinemore » (E21), and a 12% splash blend of iso-butanol and the 87 AKI gasoline (iBu12). PM mass, transient particle number concentration and size distribution, and soot mass concentration were evaluated for both start-stop operation and no start-stop operation on each fuel. Three Phase 1 & 2 cycles and as many as 27 Phase 3 & 4 cycles were performed for each fuel-mode combination. Composite FTP mass emissions for E0 and iBu12 showed increased total PM emissions with start-stop operation, but E21 showed no difference. Statistical analysis of the effects of start-stop on PM number and soot emissions showed different trends for different fuels. For example, when E0 is used with start-stop operation, the particle number decreased but the soot mass tended to increase. The results of this study have implications for hybrid vehicle operation as well because the internal combustion engine in hybrid vehicles must stop and re-start during normal operation.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1492170
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Journal Volume: 1; Conference: 2019 SAE International Powertrains, Fuels & Lubricants Meeting - San Antonio, Texas, United States of America - 1/22/2019 5:00:00 AM-1/24/2019 5:00:00 AM
Country of Publication:
United States
Language:
English

Citation Formats

Storey, John Morse, Debusk, Melanie, Huff, Shean P., Thomas, John F., Eibl, Mary A., and Li, Fanfei. Characterization of GDI PM during Vehicle Start-Stop Operation. United States: N. p., 2019. Web. doi:10.4271/2019-01-0050.
Storey, John Morse, Debusk, Melanie, Huff, Shean P., Thomas, John F., Eibl, Mary A., & Li, Fanfei. Characterization of GDI PM during Vehicle Start-Stop Operation. United States. doi:10.4271/2019-01-0050.
Storey, John Morse, Debusk, Melanie, Huff, Shean P., Thomas, John F., Eibl, Mary A., and Li, Fanfei. Tue . "Characterization of GDI PM during Vehicle Start-Stop Operation". United States. doi:10.4271/2019-01-0050. https://www.osti.gov/servlets/purl/1492170.
@article{osti_1492170,
title = {Characterization of GDI PM during Vehicle Start-Stop Operation},
author = {Storey, John Morse and Debusk, Melanie and Huff, Shean P. and Thomas, John F. and Eibl, Mary A. and Li, Fanfei},
abstractNote = {As the fuel economy regulations increase in stringency, many manufacturers are implementing start-stop operation to enhance vehicle fuel economy. During start-stop operation, the engine shuts off when the vehicle is stationary for more than a few seconds. When the brake is released by the driver, the engine restarts. Depending on traffic conditions, start-stop operation can result in fuel savings from a few percent to close to 10%. Gasoline direct injection (GDI) engines are also increasingly available on light-duty vehicles. While GDI engines offer fuel economy advantages over port fuel injected (PFI) engines, they also tend to have higher PM emissions, particularly during start-up transients. Thus, there is interest in evaluating the effect of start-stop operation on PM emissions. In this study, a 2.5L GDI vehicle was operated over the FTP75 drive cycle. Runs containing cold starts (FTP-75 cycle Phases 1 & 2) and multiple runs containing hot starts (FTP-75 cycle Phases 3 & 4) were performed each day. Note that the FTP-75 Phases 3 & 4 are identical to Phases 1 & 2 except that the engine is warmed up. Three fuels were evaluated: an 87 AKI gasoline (E0), a 21% splash blend of ethanol and the 87 AKI gasoline (E21), and a 12% splash blend of iso-butanol and the 87 AKI gasoline (iBu12). PM mass, transient particle number concentration and size distribution, and soot mass concentration were evaluated for both start-stop operation and no start-stop operation on each fuel. Three Phase 1 & 2 cycles and as many as 27 Phase 3 & 4 cycles were performed for each fuel-mode combination. Composite FTP mass emissions for E0 and iBu12 showed increased total PM emissions with start-stop operation, but E21 showed no difference. Statistical analysis of the effects of start-stop on PM number and soot emissions showed different trends for different fuels. For example, when E0 is used with start-stop operation, the particle number decreased but the soot mass tended to increase. The results of this study have implications for hybrid vehicle operation as well because the internal combustion engine in hybrid vehicles must stop and re-start during normal operation.},
doi = {10.4271/2019-01-0050},
journal = {},
issn = {0148--7191},
number = ,
volume = 1,
place = {United States},
year = {2019},
month = {1}
}

Conference:
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