On the Expansion of On-Board Diagnostics (OBD) to Electric Propulsion Systems in Battery Electric Vehicles 2021-01-0439

Currently the On-Board Diagnostics (OBD) requirements enforced by government agencies do not cover electric vehicles. Although the California Air Resources Board (CARB) mandates all light and medium duty vehicles and heavy duty engine dynamometer certified engines equipped with fossil fuel-powered engines, including all hybrid vehicles, must follow the OBD requirements in California Code of Regulation (CCR) 1968.2 and 1971.1, Battery Electric vehicles (BEVs), are exempted from OBD requirements. The legislators, such as CARB, have started to make proposals for on-board systems to monitor electric propulsion system health. In addition, there may be customer needs to obtain standard vehicle service information and the Original Equipment Manufacturers (OEMs) may also have the desire for common diagnostic strategies across different vehicle applications to lower the development costs. This paper, different from other published technical papers or proposals from OEMs or government agencies, analyzes the feasibility and compatibility of the existing OBD system design requirements, and aligns them with the need of industrial-common OBD system architecture and existing/upcoming SAE standards to propose the monitoring and reporting requirements on the identified primary propulsion system components/systems from technical point of view. This study makes some key technical proposals/solutions for the possible use of OBD-like monitoring and reporting requirements for Electric Propulsion Systems, including, what are the monitoring requirements, what is to be monitored, what are the malfunction indicator light (MIL) illumination requirements, and what are the generic scan tool (GST) interface requirements that are based on J1979-2 (i.e., Unified Diagnostic Services -UDS) to facilitate the repair service by technicians, including from independent service shops.