SAE Update - July 2023 - 24

TECH FOCUS:
COMMErCiAl AND OFF-rOAD vEHiClES
On the move to lower CO2
Despite considerable progress towards clean air in
previous decades, parts of the United States continue
to struggle with the challenge of meeting the ambient
air quality targets for smog-forming ozone mandated
by the U.S. EPA, with some of the most significant
challenges being seen in California. These continuing
issues have highlighted the need for further
reductions in emissions of NOX, which is a precursor
for ozone formation, from a number of key sectors
including the commercial vehicle sector. In response,
the California Air Resources Board (CARB) embarked
on a regulatory effort culminating in the adoption of
the California Heavy-Duty Low NOX Omnibus
regulation.
This regulatory effort was supported by a series of
technical programs conducted at Southwest Research
Institute (SwRI). These programs were aimed at
demonstrating technologies that could enable heavyduty
on-highway engines to reach tailpipe NOX levels
up to 90% below the current standards, which were
implemented in 2010, while maintaining a path
towards compliance with current heavy-duty Phase 2
GHG standards. These efforts culminated in the Stage
3 Low NOX program, the results of which have been
documented in previous publications.
In parallel with the completion of the Stage 3
technical effort, EPA began an effort to promulgate a
national heavy-duty low NOX regulation, with the goal
of completing the regulation in 2022 to support a
2027 model year implementation. As part of that
regulatory effort, EPA leveraged the test platform that
was developed under the Stage 3 program to
continue investigation of Low NOX technology
24
July 2023
This article is derived from SAE technical
paper 2023-01-0357., first author of which is
SAE member Christopher Sharp of Southwest
research institute.
capabilities and limitations. The
emission control system was
upgraded in several ways, and a
number of topics were examined
that expanded the scope of the
evaluation. These included
investigation of system
performance under a variety of
field duty cycles, examination of
extended useful life out to
800,000 miles, the impact of low
ambient temperatures on
performance, and others. The
performance of the updated
system, and the results of the
wider system investigations are
summarized in this paper.
UPDATE
SAE International
https://www.sae.org/publications/technical-papers/content/2023-01-0357/

SAE Update - July 2023

Table of Contents for the Digital Edition of SAE Update - July 2023

SAE Update - July 2023 - Cov1
SAE Update - July 2023 - Cov2
SAE Update - July 2023 - 1
SAE Update - July 2023 - 2
SAE Update - July 2023 - 3
SAE Update - July 2023 - 4
SAE Update - July 2023 - 5
SAE Update - July 2023 - 6
SAE Update - July 2023 - 7
SAE Update - July 2023 - 8
SAE Update - July 2023 - 9
SAE Update - July 2023 - 10
SAE Update - July 2023 - 11
SAE Update - July 2023 - 12
SAE Update - July 2023 - 13
SAE Update - July 2023 - 14
SAE Update - July 2023 - 15
SAE Update - July 2023 - 16
SAE Update - July 2023 - 17
SAE Update - July 2023 - 18
SAE Update - July 2023 - 19
SAE Update - July 2023 - 20
SAE Update - July 2023 - 21
SAE Update - July 2023 - 22
SAE Update - July 2023 - 23
SAE Update - July 2023 - 24
SAE Update - July 2023 - 25
SAE Update - July 2023 - 26
SAE Update - July 2023 - 27
SAE Update - July 2023 - 28
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SAE Update - July 2023 - 53
SAE Update - July 2023 - 54
SAE Update - July 2023 - 55
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