Log in | Subscribe | RSS feed

What’s New

California proposes lower NOx emission regulation for heavy-duty engines

27 June 2020

The California Air Resources Board (CARB) has released the proposed Heavy-Duty Engine and Vehicle Omnibus Regulation that includes lower NOx emission standards for heavy-duty engines and a number of associated amendments to be phased-in from 2024 through 2031.

The proposed “omnibus regulation” includes a number of regulatory changes to the heavy-duty engine and vehicle emission regulations, testing procedures, and other requirements for model year 2024 and later California-certified HD engines. These include the lower NOx and PM emission standards; a new low load certification cycle (LLC), in addition to existing FTP and RMC cycles; extension of the emission useful life and emission warranty periods; strengthening of the HD durability demonstration program; changes to the HD in-use testing program including a new in-use compliance methodology based on the moving average window (MAW) approach; changes to the on-board diagnostic (OBD) requirements; and powertrain certification test procedures for HD hybrid vehicles.

The proposed NOx and PM emission standards would apply to new California-certified heavy-duty diesel and Otto cycle (HDO) engines intended for vehicles with GVWR > 10,000 lbs. The proposed NOx emission standards would be implemented in two steps:

An important part of the proposal are new useful life periods of up to 800,000 miles, fully phased-in through 2031. For Class 8 vehicles, MY 2027-2030 engines must achieve a 0.035 g/bhp-hr FTP/RMC NOx standard between 435,000 and 600,000 miles full useful life (FUL), and engines beyond 2031 must achieve 0.04 g/bhp-hr NOx between 435,000 and 800,000 miles.

The NOx emission limit for the LLC cycle would transition from 0.2 g/bhp-hr (MY 2024-2026) to 0.05 g/bhp-hr (2027 and beyond at 435,000 miles). MY 2027-2030 engines would need to meet an LLC limit of 0.09 g/bhp-hr at FUL of 600,000 miles, and engines of MY 2031 and later would need to meet an LLC limit of 0.10 g/bhp-hr at FUL of 800,000 miles.

The regulatory package also includes an optional 50-state certification program for MY 2024-2026 at 0.1 g/bhp-hr NOx over the FTP and 0.3 g/bhp-hr over LLC.

CARB will consider the proposed regulation at its August 27, 2020 hearing. CARB will confirm whether the hearing will be held in person at its Sacramento headquarters or remotely. Written public comments can be submitted electronically by August 25, 2020.

Source: CARB