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Study of light-duty gasoline vehicle cold climate NOx and particulate number emissions in real-world driving conditions

  • Author / Creator
    Lotfi, Ali
  • Cold climate Nitrogen Oxides(NOx) and Particulate Number(PN) real-world driving emission factors of a gasoline direct injection light-duty vehicle were measured using a portable emission measurement system. The vehicle was driven at the ambient temperature of 􀀀15C in a series of repeated experimentations in an urban route in the city of Edmonton in winter 2020. The NOx emission factor that was obtained at the cold ambient temperature of 􀀀15C was 466  57 mg/km, to put this number in perspective it is 7.1 times higher than the 65 mg/km Tier2 emission regulation limit for a 2008 model year car. The same car, emitted 56  7 mg/km NOx emissions at ambient temperature of +15C. This increase in cold temperature is attributed to an increase in friction losses, reduced fuel mixing, and catalyst light-o temperature. The PN emission factor results were obtained at the cold ambient temperature of 􀀀15C at (1:59  1)  1011 #/km. The value is 2.3 times higher than PN emission factors at an ambient temperature of +5C at (6:8  2:4)  1010 #/km. These results show the importance of using real-world driving emissions in a cold climate for NOx and particulate emissions of vehicles. A much larger emission factor obtained in cold ambient temperature and dierent driving behaviours shows the relative importance of research for future emission regulation tted to the cold climate of Canadian cities. Further steady-state driving speed and variation of driving behaviour testing showed that high instantaneous vehicle emissions cause a large sum of total vehicle emissions, although they are produced in a small fraction of driving time. The experimental results show the NOx emission factors for constant speed test increases with increasing speed. The results show the emission factor of (357) mg/km for 80 km/h, (98  12) mg/km for 90 km/h, (174  9) mg/km for 100 km/h, and (232  24) mg/km for 110 km/h. The correction factor was found that the increase of NOx with speed relates to vehicle speed squared. Real-world driving NOx emission of the vehicle was also measured using two types of driving behaviour. The behaviour was quantied by the average positive acceleration of the vehicle over the same route. The result shows the engine spike of NOx is sensitive to the transient operating condition of the engine. The NOx increases from (67) mg/km for normal driving behaviour to 12.7 times higher to (856) mg/km for aggressive driving behaviour. The average positive acceleration for the normal driving behaviour and aggressive driving behaviour were 0.78 ( m s2 ) and 2.92 (m s2 ); respectively.

  • Subjects / Keywords
  • Graduation date
    Spring 2021
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-nrtj-9d93
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.