Truck & Off-Highway Engineering - August 2023 - 4

TECHNICAL
INNOVATIONS
DIAGNOSTICS
OBD evolves for ICE and zero-emission propulsion systems
SAE INTERNATIONAL
BOARD OF DIRECTORS
Todd Zarfos
President
Carla Bailo
2024 President
Srinivasa (Sri) Srinath, Ph.D
2022 President
Susan Ying, Ph.D
Vice President - Aerospace
Daniel Nicholson
Vice President - Automotive
Figure 1: Setup of a traditional diagnostic communication system in the workshop.
On-board diagnostics (OBD) systems support the
protection of the environment against harmful
pollutants such as carbon monoxide (CO), nitrogen
oxide (NOx), hydrocarbons (HC) and particulate
matters (PM) emitted by combustion engines.
OBD regulations require passenger cars
and light-, medium- and heavy-duty trucks to
support a minimum set of diagnostic information
to external (off-board) " generic " test equipment.
For the purpose of communication, both the
test equipment and the vehicle must support
the same communication protocol stack. The
communication protocol SAE J1979, also
known as ISO 15031, that has been in use for
decades will be replaced by SAE J1979-2 for
vehicles with combustion engines and by SAE
J1979-3 for zero-emission-vehicle (ZEV) propulsion
systems.
SAE J1979-2 was published in April 2021 and
is allowed by the California Air Resources
Board (CARB) starting with the 2023 model
year and is mandatory by 2027 MY. SAE J19793
was published in December 2022. CCR
§1962.5 states that SAE J1979-3 is mandated
for all ZEVs by 2027. Both protocols are based
on ISO 14229-1 UDS.
Audley Brown
Vice President -
Commercial Vehicle
Andrew Jeffers
Treasurer
David L. Schutt, Ph.D
Chief Executive Officer
Gregory L. Bradley, Esq.
Secretary
Judy Curran
Mary Lee Gambone
Michael Weinert
Joan Wills
SAE International Sections
SAE International Sections are local
units comprised of 100 or more SAE
International Members in a defined
technical or geographic area. The purpose
of local Sections is to meet the technical,
developmental, and personal needs of the
SAE Members in a given area. For more
information, please visit sae.org/sections
or contact SAE Member Relations Specialist
Abby Hartman at abby.hartman@sae.org.
SAE International
Figure 2:
Diagnostic
communication
protocol stacks
mapped to the
OSI model.
4 August 2023
Collegiate Chapters
Collegiate Chapters are a way for SAE
International Student Members to get
together on their campus and develop
skills in a student-run and -elected
environment. Student Members are vital
to the continued success and future of
SAE. While your course work teaches
you the engineering knowledge you
need, participation in your SAE Collegiate
Chapter can develop or enhance other
important skills, including leadership,
time management, project management,
communications, organization, planning,
delegation, budgeting, and finance. For
more information, please visit students.
sae.org/chapters/collegiate/ or contact
SAE Member Relations Specialist Abby
Hartman at abby.hartman@sae.org.
TRUCK & OFF-HIGHWAY ENGINEERING
BOTH IMAGES: SOFTING
http://www.sae.org/sections http://www.sae.org/chapters/collegiate/
Truck & Off-Highway Engineering - August 2023

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