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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Specific NO and NO2 emissions from a wide range of current and future LD and HD vehicles in urban driving conditions

Despite efforts and success of NOx reduction from vehicle engines by means of emission legislation NO2 concentrations in busy urban traffic areas have not decreased any more. A research of primary NOx, NO and NO2 emissions was made to evaluate source contribution of different vehicle categories to concentrations in urban air. The study comprised 28 pre- Euro to EEV city buses of model years 2000 - 2008, 8 trucks conforming Euro 4 emission limits, and 14 current diesel and gasoline passenger cars representing a cross-section of the current fleet in Finland. The light duty (LD) vehicles were of model years 1986 - 2007. Vehicles were run using real urban driving cycles dedicated and tailored to each engine category. NO and NO2 were monitored on-line over transient cycles. For the passenger cars both specific and vehicle number weighted NOx emissions were the highest for gasoline vehicles without three-way catalytic converters (TWC). These currently represent 10 % of the Finnish LD in-use fleet. The share of new LD diesel vehicles with powerful oxidising catalysts and/or diesel particulate filters is already high, and increasing rapidly. These are the most prominent sources of direct NO2 from LD city traffic. Both NOx and NO2 emissions from the passenger cars were elevated even more as the cars were driven using a realistic rush hour driving cycle instead of warm ECE15 cycle, showing 40 % and 44 % increase, respectively. As for heavy duty (HD) NOx emission, the highest emitters were mainly the Euro 2 & 3 buses, in Braunschweig and other city cycles. There were, however, also model year 2006-07 Euro 4 & EEV vehicles among the high NOx emitters. For NO2 several Euro 4 & EEV buses and trucks emitted 30-60% NO2 shares. NO and NO2 emissions for HD buses, in g/km, are very dependent on the way of urban driving due to highly variable travel speed of the cycles, e.g. Braunschweig, NYBus, WTVC or Helsinki city. With the year 2007 fleet, in streets with high shares of public traffic, over 90 % of both direct NOx and NO2 is HD originating, due to the very high, 10- to 50-fold higher, emission levels of HD vehicles compared with passenger cars. For NO2, the situation has, however, started to change with the fast increasing number of new diesel passenger cars. Conclusively, as regards amounts of direct NO2 emissions, there are two problematic groups among new vehicles, both LD and HD diesel vehicles fitted with an oxidizing catalyst and/or a particulate filter. For the covering abstract see ITRD E141518.

  • Corporate Authors:

    Technical University Graz

    Institute for Internal Combustion Engines and Thermodynamics, Inffeldgrasse 25
    A-8010 Graz,   Austria 
  • Authors:
    • LAPPI, M
    • LAURIKKO, J
    • ERKKILA, K
    • PELLIKKA, A P
    • KOSKENTALO, T
  • Conference:
  • Publication Date: 2008

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 01323375
  • Record Type: Publication
  • Source Agency: TRL
  • Files: ITRD
  • Created Date: Dec 22 2010 8:48AM