CARB Workshop Previews Upcoming Heavy-Duty Diesel Changes

CARB continues to drive lower NOx emissions for heavy-duty engines and vehicles on the road.

By Arthur Foerster and Reed McCalib

On January 23, 2019, the California Air Resources Board (CARB) held a public workshop to discuss the agency’s ongoing regulatory emissions overhaul for on-highway, heavy-duty diesel engines and vehicles. Based on the agency’s position that reducing oxides of nitrogen (NOx) from heavy-duty vehicles is necessary to attain air quality standards, CARB staff made clear the agency’s intention to “dramatically lower emissions” and to ensure emissions remain low throughout the vehicles’ operational lives. CARB staff indicated that the agency will work collaboratively with the EPA and its “Cleaner Trucks Initiative” to develop harmonized national requirements. (For a more in-depth look at this initiative, please see Latham’s previous blog post.) Staff stressed, however, that CARB will adopt new, more stringent rules regardless of what EPA does and expects to do so on a more accelerated timeline than EPA. CARB is undertaking what it says is a necessary “multi-pronged holistic approach” and intends to release draft rules later this year on a number of regulatory fronts, including more stringent standards, greater durability, and more testing.

More Stringent Standards

CARB staff reiterated the agency’s intention to lower the NOx emissions standard for new, on-highway heavy-duty diesel engines by as much as 90% below the current standard of 0.2 grams per brake horsepower hour (g/bhp-hr). Although CARB staff have not settled on a specific number, they indicated a target range of 0.015 to 0.035 g/bhp-hr. According to staff, the CARB-funded research being performed by the Southwest Research Institute (SwRI) to assess the feasibility of lower NOx emissions is not complete. The SwRI research results, along with other data such as cost impacts, will determine the new NOx standard expected later this year.

At the workshop, industry representatives raised concerns about the lack of lead time and the unknown target to which manufacturers are supposed to design new engines. CARB staff, however, dismissed those concerns, noting that the public (including manufacturers) will be kept in the loop regarding progress on the potential new standard through additional workshops. CARB also is considering a step-down, phased approach over several years for standard implementation and the possibility of a California NOx credit program that currently exists at only the federal level. CARB staff, however, provided few details and many aspects remain unclear, including when the final standard will take effect or how long the phase-in period will be. The results of the SwRI demonstrations may provide more clarity with respect to a final NOx emission standard and implementation timeline. (CARB staff also indicated that the agency is looking to reduce the particulate matter standard, but few specifics were provided.)

Greater Durability

To help ensure that the more stringent NOx emissions standards are met, CARB staff also intend to amend regulations related to useful life, warranty, and demonstration of durability. Useful life is the period during which an engine is required to demonstrate emissions compliance, and manufacturers generally must warrant that their engines are free from defects in materials and workmanship that would cause the engine to fail to conform to applicable standards during the required warranty period.

As discussed in Latham previous post, CARB recently increased warranty periods for model year 2022 and later new heavy-duty engines to better reflect its view of current useful life periods. CARB is now going beyond these increases (Step 1) to lengthen the useful life and further prolong warranty requirements for model year 2026 and later heavy-duty engines (proposed Step 2). According to CARB staff, the real-world operational longevity of heavy-duty vehicles is much greater than currently required useful life and warranty periods. CARB intends to lengthen the periods to better reflect what the agency says is typical usage of modern vehicles. CARB staff indicated that the heightened requirements may encourage more durable components, reduce tampering, and ensure better maintenance and timely repairs of emission-related components. The amendments would provide substantial increases over current levels.

CARB staff will also propose changes to how manufacturers demonstrate the durability of emission-related components during certification, because they believe the current method (i.e., aging engine ~35-50% of useful life) does not fully represent real life component failures and deterioration. CARB staff are proposing new durability testing requirements for model year 2022 and later engines, which will significantly increase the required aging process.

CARB staff’s presentations generated significant discussion among workshop participants. Industry representatives pointed out that increasing useful life and warranty periods, along with increased durability aging, will have significant impacts on product timing and costs. For instance, extended aging could require manufacturers to test multiple replacement components throughout the testing period, which in many cases may not be practical or even necessary. There also likely would be downward pressure on component suppliers. CARB staff requested that participants support their claims by submitting relevant data.

More Testing

A third broad category on CARB’s “low NOx” agenda is to update emissions testing procedures in both laboratory and on-road environments. For laboratory certification testing, CARB is developing a new test cycle with SwRI that is intended to account for low-load operations of heavy-duty vehicles. According to CARB staff, NOx emissions from low-load operations are becoming increasing significant. The five conditions CARB intends to test in the new cycle are sustained low-load operation, long idling, short idle cooling, post-cooling breakthrough, and mid-speed cruising. Candidate cycles are designed to include one example of each type of event. CARB staff have narrowed down the test cycle candidates to two leading options: (1) 90 minute overall cycle including 30 minutes of sustained low-load operation, and (2) 81 minute overall cycle including 30 minutes of sustained low-load operation and a shorter mid-speed cruise segment. The new test cycle would be in addition to existing certification tests such as the federal test procedure (FTP). Some workshop participants raised concerns that meeting the new tests might negatively impact greenhouse gas (GHG) emissions. CARB staff are considering the matter and intend to submit a preliminary proposal in March 2019.

With respect to heavy-duty in-use testing, CARB intends to implement a moving average windows (MAW) method to gauge emissions in real, on-road conditions, modelled on the European method. CARB claims that the MAW method captures more test time and emissions and will decrease overall pass rates compared to the current federal not-to-exceed (NTE) method. In-use tests will still be conducted with fleet operators or manufacturers behind the wheel on a real-world fleet route. A draft proposal for in-use testing procedures is expected in April 2019, and implementation will begin in 2022 under current NOx standards. CARB staff indicated that meeting the new, in-use testing should only involve a calibration rather than any significant hardware changes. However, some participants disagreed and noted the potential adverse impact on GHG emissions. Industry participants were also concerned about sufficient lead time and additional testing costs.

Looking Forward

CARB intends to roll out the regulatory changes described above over a period of at least six years, beginning as early as 2022. New rules will be implemented each year thereafter until 2027. Although the exact timeline for each of these regulatory updates is still unknown, CARB intends to crystallize many of its proposals in the coming months to give industry participants what the agency considers sufficient lead time to plan for the changes. The frequency of changes and unknown targets, however, raise significant concerns in an industry in which long lead times are necessary to implement engine and vehicle modifications. Latham & Watkins will continue to monitor and report on developments in the heavy-duty NOx emissions space.