Euro 6 d-TEMP PHEV and diesel passenger cars on-road research

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Based on the results obtained in the project it can be stated that PHEVs could provide an effective additional measure for reducing CO2 emissions in typical Finnish daily trips where 93% of daily mileage is less than 50 km. Results showed that PHEVs are capable of covering the typical Finnish daily mileage fully electrically in different driving conditions. However, results also showed that the electric range drops greatly when the ambient temperature decreases below roughly 5 °C. If a PHEV is used with an empty battery, CO2 emissions are well above the officially declared values. On the commuter test route where the test started with an empty battery, PHEVs produced 5% to 66% higher CO2 emissions depending on the PHEV compared to a diesel car. However, on the city test route, two of the PHEVs were in best case capable of diesel car-like CO2 emissions when the test was started with an empty battery. The NOx emissions of the tested PHEVs, diesel car and van were at a low level, even well below the regulatory limit values. Overall, PHEVs performed the best, producing NOx emissions mostly below 0.01 g/km, corresponding to a conformity factor (CF) value of 0.17 and below. There was no observed significant increase in NOx emissions during the change of propulsion from electric drive to ICE drive, even in sub-zero Celsius temperatures. The NOx emissions of the diesel car were also well below the legislative limit value. Emissions varied between 0.005 g/km to 0.092 g/km depending on test route and ambient conditions; these correspond to CF values of between 0.063 to 1.15. The ambient temperature had a clear effect on NOx emissions, as an increasing trend was observed as a function of decreasing ambient temperatures. A van was tested on a test route replicating a typical delivery journey in a suburban area. NOx emissions were 0.05 g/km when start-stop functionality was deactivated, and 0.065 g/km when it was activated. These figures correspond to CF values of 0.40 and 0.52. NOx emission performance was also tested against the proposed limit values of Euro 7 regulation. PHEVs were capable of meeting the limit values with clear margins. The diesel car greatly exceeded the proposed limit values on cold start routes. However, it did meet the limit values in warm start tests. NOx emissions from the van were close to the limit value and in some tests, they were below the limit. In general, PN emissions were well below the regulatory limit values in every test condition with all tested vehicles. In summary, it can be stated that the tested vehicles are capable of low NOx and PN emissions in different driving and ambient conditions. In addition, PHEVs with renewable fuels like high ethanol fuels (E85) could provide effective additional measures for reducing CO2 emissions among BEVs. Especially on short trips, regularly charged PHEVs provide close to BEV energy consumption and thus CO2 emissions. For longer distances, renewable fuels would ensure a low carbon footprint. To achieve regular charging all incentives that discourage the user to charge the battery regularly should be removed.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages46
Publication statusPublished - 31 Mar 2023
MoE publication typeD4 Published development or research report or study

Publication series

SeriesVTT Research Report


  • Euro 6 emissions
  • PHEV
  • CO2 emissions
  • E85
  • E25
  • HVO
  • RDE emissions
  • NOx emissions
  • PN emission


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