Civil Engineering Reference
In-Depth Information
ISO TC22/SC3/WG1 Data Communication, SAE and JSAE (Japanese SAE) set-
up a joint task force to define the principles and concept for a future single protocol
solution. This activity started in early 2003 with a document from the WWH-OBD
informal group called:
GENERAL PERFORMANCE CRITERIA FOR HDV EMISSION-RELATED
OBD
Communication protocols
WWH-OBD meeting 6/7 November 2002—DECISION 10
This document included requirements related to the following topics:
1. Needs for a common HDV OBD Communication Protocol:
- Today, there exist two competing communication protocols for the applica-
tion of OBD to HDVs—SAE J1939 and ISO 15765.
- In the short term, it seems that both communication standards will exist in
parallel but the primary aim must be to have one common protocol, which
would be to the benefit of all sectors operating under the umbrella of “the
automotive industry”.
2. Needs for the legislator:
- The scope of the standard must include both current chassis control and emis-
sion control systems and must provide for the seamless addition of further
control systems (both simple and complex) as the market develops.
- The standard must offer the capability to react to the wishes of the legislator
in a quick and effective manner. This particularly encompasses the following
likely future requests:
a. the standard should be extendable to passenger cars and light commercial
vehicles and
b. the standard should offer the ability to retrieve the data necessary for in-
use compliance testing, e.g. to identify vehicle operation in/out of a “Not
to Exceed” (NTE) zone (if NTE remains a valid concept in the future),
cumulative time/distance travelled in/out of an NTE zone, operation of
auxiliary control devices, torque/load readings for engine testing or to
enable the use of portable emission measurement systems (PEMS).
- The standard must include the possibility for the application of wireless com-
munication between the OBD system and a remote interrogation unit.
- The standard must offer the ability to retrieve in-use OBD performance data,
e.g. OBD monitoring frequency, vehicle operation frequency and time of
operation.
- Clear and precise specifications within the communication protocol, with
minimal variations that will result in a minimum chance of difference in inter-
pretation that could lead to vehicles being produced that are unable to com-
municate fully with a generic scan tool (note: some vehicles may not actually
utilize hard-wired scan-tools in the future).
- Availability of test equipment that can verify that communication protocol
specifications are being adhered to on production vehicles.
3. Needs for inspection and maintenance (I/M) testing (roadworthiness testing or
roadside spot-checks):
