US EPA proposes new emission standards for heavy-duty engines
7 March 2022
Today the US Environmental Protection Agency (EPA) proposed new, stronger emission standards for heavy-duty vehicles and engines starting in model year (MY) 2027. The proposed standards would reduce emissions of NOx and other pollutants from heavy-duty diesel and gasoline engines, and set updated ‘Phase 2’ GHG standards for certain categories of commercial vehicles.
The proposed emission standards are largely harmonized—beginning with MY 2027—with the California low NOx standards, so-called Omnibus regulation, adopted in August 2020. However, there are some differences in the emission limits and other provisions. The particulars can be found in the EPA proposed rule.
The EPA has proposed two regulatory options, both of which would set stronger emission standards for NOx beginning in MY 2027, adopt the LLC test cycle and emission standards in addition to the FTP & SET standards, increase regulatory useful life, and increase emissions-related warranty periods.
- Option 1 would implement stronger NOx standards in two steps. The first increase in stringency would be in MY 2027 (NOx = 0.035 g/bhp-hr over 600,000 mi), and the second would be in MY 2031 (NOx = 0.020 g/bhp-hr over 435,000 mi and 0.040 g/bhp-hr over 800,000 mi).
- Option 2 would immediately jump to full implementation of a NOx standard of 0.050 g/bhp-hr in MY 2027. The proposed useful life period is 650,000 mi.
The above useful life periods are applicable to heavy heavy-duty engines; light- and medium-heavy-duty engines have shorter useful life periods. The proposed useful life periods are harmonized with those in the California Omnibus regulation.
The EPA proposal also introduces stronger standards for other pollutants: PM = 0.005 g/bhp-hr, HC = 0.040 g/bhp-hr, and CO = 6.0 g/bhp-hr.
The proposed revisions to existing Phase 2 GHG standards for MY2027 and later would set updated GHG emission standards for subsectors where electrification is advancing at a more rapid pace. These sectors include school buses, transit buses, commercial delivery trucks, and short-haul tractors.
The EPA intends to finalize the proposed emission standards by the end of 2022.
The proposal is the first step in EPA’s “Clean Trucks Plan”—a series of clean air and climate regulations that the agency intends to develop over the next three years. These planned future regulatory actions include:
- Setting stronger emissions standards for medium-duty commercial vehicles for MY 2027 and later. These revised standards are to be proposed in combination with new standards for light-duty vehicles for MY 2027 and beyond.
- Setting ‘Phase 3’ GHG standards for heavy-duty vehicles beginning as soon as MY 2030 that are significantly stronger than the MY 2027 GHG standards.
Source: US EPA