A new On-Board Diagnostic System standard for the measurement of the emissions of heavy duty vehicles such as trucks and buses better was approved yesterday by the UN/ECE organisation which deals with harmonising global standards. Such systems are required by regulators around the world to ensure that vehicles¡¯ emissions performance can be monitored, but the new Global Technical Regulation (GTR) sets out new global OBD performance requirements to which engine manufacturers must comply when developing new engines.

The GTR specifies a basic set of demonstration requirements for manufacturers so that compliance with emissions legislation can be demonstrated in a consistent manner. Also included are requirements to standardise the communication of on-board information to off-board devices, so as to assist in maintenance of increasingly complex diesel engines. These communication protocols will also facilitate the future use of On Board Diagnostic systems for roadworthiness purposes for heavy-duty vehicles.

Of particular importance (with respect to the use of On-Board Diagnostic systems as a roadworthiness indicator) is the introduction of a malfunction warning signal on the dashboard, dedicated to indicating any malfunction in the engine or emissions control system which results in an increase in emissions. On detection, a malfunction code is stored in the memory of the system, allowing vehicle operators, maintenance staff, inspectors and enforcement authorities to review the performance of vehicles and make informed decisions about the roadworthiness of the vehicle.

The European Commission says OBD is likely to become increasingly important in future roadworthiness/inspection and maintenance procedures, and the regulation reflects this expectation. It requires standardised On-Board Diagnostic data to be accessible from an access port. Telematic functions which allow wireless communication of the data are seen as increasingly important, which is why the Regulation relies on the work of the International Standardisation Organisation (ISO) which will further develop this aspect.

The relevant official document 2006/130 can be downloaded from:

http://ec.europa.eu/enterprise/automotive/unece/gtr.htm