Session OBD – OBD für Pkw und Nfz
All current OBD legislation worldwide are based on either the European or the US legislation. Emission limits for combustion engines are the basis for the OBD regulations. New technologies, e.g. the electrification, place other components as air conditioning system, brake system, electric motor and HV-battery in the USA directly or indirectly into the OBD focus. The influence of the network topology raised because the number of the electric control units cross-linked under OBD criteria increased, especially as only a limited number of legally allowed diagnostics addresses are available.
This leads to network topologies, that have to be considered and evaluated critically under the premise of OBD-communication, particularly with specific timing requirements. Thus the OBD-requirements become a direct criterion for the network topology of electric control units and sensors/actuators in modern vehicles. New bus systems for sensors and actuators (e.g. LIN) must be considered also with respect to OBD requirements. Additionally to the increased number of the ECUs in the OBD-Network also functions and diagnostics of one ECU have direct influence on functions and diagnostics in other ECUs within the OBD network. Therefore signals, that are provided in the OBD network, must be evaluated under OBD requirements and must be flagged for OBD relevance in the bus system. Future OBD-communication concepts adapted to the increasing complexity must be agreed with the legislators and defined in standardization committees.
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