Heavy Duty Diesel Emission Standards Regulation Evolution Review - Current Outcomes and Future Perspectives 2019-36-0174

Heavy duty vehicle (HDV) segment, as an important source of emissions that strongly impact air quality and human health - especially in urban centers - has been continuously challenged by the increasingly stringent emission limits. The adoption of emission standards for the heavy duty industry was initially launched by the United States, followed by the European Union and Japan, and, subsequently, by other countries, like Australia, Brazil, China and India, among others, generally with a time lag. This continuous “cleaning” effort has led to the current rigorous emission limits - materialized by the so called U.S. EPA 2010 and Euro VI and their foreign variants - which have provided huge emissions reductions (HC, CO, NO_x, PM and smoke and, more recently, CO₂). Nevertheless, due to air quality and global climate change concerns (basically derived from the air quality non compliance, associated with cities' pollution hotspots, as well as greenhouse gas emissions) there is still a regulatory demand for further emissions control improvement. In this scenario, the heavy duty vehicle industry has pursued not only increasingly stringent emission targets, as well as the compliance of emission performance throughout the vehicle lifecycle, greenhouse gas emissions (GHG) control, as well as the compatibility with alternative fuels (biodiesel, renewable diesel, biogas, etc.). In this context, governments and HDV industry are currently engaged in an effort to develop an important step in the improvement of worldwide standardized HDV emission limits. This work is supposed to present an overview of HDV emission control technologies, associated with the evolution of emission standards, with an emphasis on the in-use performance and its intrinsic emission trade-offs, as well as the inherent required infrastructure (fuel quality and additive requirement/availability), followed by a summary of some countries' cleaning implementation pathways, associated with both fleet renewal and retrofit of current fleets. Lastly, the work presents a snapshot of the strategies and the available technological pathways for further improvements on emission standards.