Truck & Off-Highway Engineering - August 2021 - 8

TECHNICAL INNOVATIONS
DIAGNOSTICS
Tools and templates for the creation of customized diagnostic tester
Figure 1: A generic vehicle communication interface (VCI) connects the device under test (DUT) with
the DUT-specific tester (TST).
On-board diagnostics (OBD) is required
to monitor emissions-related components
such as heavy-duty diesel engines
and their emissions control systems.
Though the use of electric drives is increasing,
not only in passenger cars but
also in heavy-duty commercial vehicles
and mobile machinery, the legally required
OBD system will not disappear.
Independent of the current legal situation,
the OBD system is being expanded
and given new tasks. Especially in autonomous
road-vehicles and automated
mobile machines, this enhanced onboard
diagnostics is indispensable to
ensure availability and safety.
Diversity is not always an advantage,
especially when it creates unnecessary
effort and costs. The current situation is
that the industry faces three different
OBD protocols: Heavy-Duty (HD)-OBD
(SAE J1939-73), SAE-OBD (SAE J1979),
and World-Wide Harmonized (WWH)OBD
(ISO 27145). All three are based on
the same set of " OBD modes " and exclusively
support emissions-related
functions. For enhanced diagnostics,
the internationally standardized UDS
(unified diagnostic services) on CAN
(ISO 14229-3 and ISO 15765-4) can be
considered as state of the art. As a result,
manufacturers of vehicles and machines
that are powered by heavy-duty
diesel engines implement both OBD on
CAN and UDS on CAN.
To solve this diversity problem, the
WWH-OBD as it is specified in the
Global Technical Regulation GTR No. 5
Table 1: International standards specify the
entire diagnostic system.
of the United Nations has been developed
to replace both SAE-OBD and
HD-OBD protocols. WWH-OBD is based
on UDS, meaning that only one diagnostic
protocol is necessary for emissions-
and safety-related OBD and enhanced
diagnostics: UDS on CAN.
" Replacing proprietary diagnostic test
equipment by an internationally standardized,
data-driven and cloud-based
technology makes both technical and
economic sense, " said Julian Erber, product
manager at Softing Automotive.
Diagnostic test equipment
The generic term " diagnostic test equipment "
is referred to as the Tester (TST).
Figure 2: Softing
TDX for engines and
emissions control
systems (use case
example).
8 August 2021
TRUCK & OFF-HIGHWAY ENGINEERING
ALL IMAGES: SOFTING

Truck & Off-Highway Engineering - August 2021

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - August 2021