A roadmap for heavy-duty engine CO2 standards within the European Union framework

Published Sun, 2017.09.03 | By

Rachel Muncrief and Felipe Rodríguez


Analyzes the benefits of establishing separate engine CO2 standards in addition to full-vehicle regulations to specifically drive improvements in heavy-duty engine efficiency. Outlines a possible pathway for the development and implementation of separate engine CO2 standards for heavy-duty vehicles within the regulatory framework of the European Union.

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Four countries—Japan, the United States, Canada, and China—now have CO2 or efficiency standards for heavy-duty vehicles (HDVs). The United States and Canada have separate engine standards in addition to full-vehicle regulations to specifically drive improvements in engine efficiency. 

Recent studies show that there is potential to reduce fuel consumption of heavy-duty vehicles by 30% to 40%, compared to the present, using conventional technologies aiming to increase the diesel engine’s efficiency and reduce the vehicle’s road-load power demand. On average, a third to a half of this projected fuel-efficiency gain comes from improvements in engine thermal efficiency.

There are a number of benefits to instituting a separate engine standard in conjunction with a full vehicle standard. These include establishing a link between NOx and CO2 emissions, ensuring efficiency improvement in vehicles not covered by the full vehicle standard, extending the engine type-approval framework to include CO2 emissions, ensuring long-term investment in engine R&D, incentivizing long-term investment in engine R&D, and ensuring durable CO2 emissions reductions throughout the lifetime of the vehicle.

Setting an engine standard entails three steps: (1) setting the baseline, which would typically involve collecting and analyzing recent engine CO2 data; (2) segmenting the market to determine how to group the heavy-duty engines for the purpose of regulation, a process that would typically take into consideration the type of vehicle in which the engine will be used; and (3) defining the stringency and timing to determine the ambition of the regulation. Using the U.S. heavy-duty engine CO2 standard for guidance, this briefing paper investigates the potential for a similar standard in the EU.