NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

Sangchul Ko,Junhong Park,Jongchul Lee,Jongmin Kim,Gunwoo Kang,Jongtae Lee,Hyungjun Kim

doi:10.3390/en13010218

Sangchul Ko, Junhong Park + Show 5 more

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https://doi.org/10.3390/en13010218

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Abstract

Despite the strengthening of vehicle emissions standards and test methods, nitrogen oxide (NOx) emissions from on-road mobile sources are not being notably reduced. The introduction of real driving emission (RDE) regulations is expected to reduce the discrepancy between emission regulations and actual air pollution. To analyze the effects of RDE regulations on heavy-duty diesel vehicles, pollutants emitted while driving were measured using a portable emission measurement system (PEMS) for Euro 5 and Euro 6 vehicles, which were produced before and after RDE regulations, respectively. NOx emissions were compared as a function of emissions allowance standards, gross vehicle weight (GVW), average vehicle speed, and ambient temperature. NOx emissions from Euro 6 vehicles were found to be low, regardless of GVW; emissions from both vehicular categories increased with a decline in the average speed. To reflect real road driving characteristics more broadly in the RDE test method for heavy-duty vehicles, it is necessary to consider engine power, which is a criterion for classifying effective sections, in the moving average window (MAW) analysis method, as well as including cold start conditions.

Highlights

Emission allowance standards and test methods for vehicles are continuously being strengthened to reduce the air pollutants emitted from diesel vehicles [1]
Low temperatures were found to have no Category M3 significant effect on nitrogen oxide (NOx) emissions because most heavy-duty diesel vehicles (HDVs) have insulated exhaust pipes; the temperature of the exhaust gas did not fall below the activation temperature of the catalyst under the
The number of test vehicles cannot be used as a representative value as there are very few test vehicles, and only Euro 6 vehicles are considered

Summary

Introduction

Emission allowance standards and test methods for vehicles are continuously being strengthened to reduce the air pollutants emitted from diesel vehicles [1]. The Euro 6 standards have tightened the limits for particulate matter and nitrogen oxide (NOx) by approximately 90% from the Euro 3 standards; they have not contributed to the improvement of air pollution in large cities as much as expected. The PM10 concentration in Seoul has been continuously decreasing since 2001, but the NO2 concentration has not shown a clear reducing trend [3]. The Joint Research Centre of the European Commission has identified problems with NOx emissions of diesel vehicles produced under European regulations, being 4 to 7 times higher than the indoor certification standards [4]. It is important to resolve the discrepancy between these emission regulations and actual air pollution [3,4,5]

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