European Regulatory Framework and Particulate Matter Emissions of Gasoline Light-Duty Vehicles: A Review

Barouch Giechaskiel,Panagiota Dilara,Leonidas Ntziachristos,Ameya Joshi

doi:10.3390/catal9070586

Barouch Giechaskiel, Panagiota Dilara + Show 2 more

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https://doi.org/10.3390/catal9070586

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Abstract

The particulate matter (PM) emissions of gasoline vehicles were much lower than those of diesel vehicles until the introduction of diesel particulate filters (DPFs) in the early 2000s. At the same time, gasoline direct injection (GDI) engines started to become popular in the market due to their improved efficiency over port fuel injection (PFI) ones. However, the PM mass and number emissions of GDI vehicles were higher than their PFI counterparts and diesel ones equipped with DPFs. Stringent PM mass levels and the introduction of particle number limits for GDI vehicles in the European Union (EU) resulted in significant PM reductions. The EU requirement to fulfill the proposed limits on the road resulted to the introduction of gasoline particulate filters (GPFs) in EU GDI models. This review summarizes the evolution of PM mass emissions from gasoline vehicles placed in the market from early 1990s until 2019 in different parts of the world. The analysis then extends to total and nonvolatile particle number emissions. Care is given to reveal the impact of ambient temperature on emission levels. The discussion tries to provide scientific input to the following policy-relevant questions. Whether particle number limits should be extended to gasoline PFI vehicles, whether the lower limit of 23 nm for particle number measurements should be decreased to 10 nm, and whether low ambient temperature tests for PM should be included.

Highlights

Driven by the greenhouse gas emission reduction policies and the goal to keep the global temperature increase below 2 ◦ C, the European Union (EU) is committed to reducing CO2 emissions by 20% in 2020, and by 80–95% in 2050 compared to 1990 levels [1]
It must be repeated that all results refer to vehicles over transient driving cycles and not engines operating on specific steady-state modes, to better reflect actual operation emission levels
The picture changed when particulate filters were installed on diesel vehicles and gasoline direct injection (GDI) vehicles were introduced in the market

Summary

Introduction

Driven by the greenhouse gas emission reduction policies and the goal to keep the global temperature increase below 2 ◦ C, the European Union (EU) is committed to reducing CO2 emissions by 20% in 2020, and by 80–95% in 2050 compared to 1990 levels [1]. Describes how the transport system can reduce its emissions by 60% in the same period: the target is a 50% shift away from conventionally fueled cars by 2030, phasing them out from cities by 2050. Similar policies are followed globally [3,4] One contributor in this direction is the replacement of traditional port fuel injection (PFI). GDI engines are not new: 100 years ago the very first test rig run of a GDI engine was successfully carried out [6]. This engine was produced for use in boats in the 1930s and for aircrafts in the 1940s. Research into GDIs increased in the 1990s with the development of engine management systems capable of supporting the Catalysts 2019, 9, 586; doi:10.3390/catal9070586 www.mdpi.com/journal/catalysts

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