SAE J2578_201408

This SAE Recommended Practice identifies and defines requirements relating to the safe integration of the fuel cell system, the hydrogen fuel storage and handling systems (as defined and specified in SAE J2579) and high voltage electrical systems into the overall Fuel Cell Vehicle. The document may also be applied to hydrogen vehicles with internal combustion engines. This document relates to the overall design, construction, operation and maintenance of fuel cell vehicles. This revision to SAE J2578 represents an evolution to requirements for the integration of hydrogen and electrical systems for hydrogen and fuel cell vehicles (FCVs). Rationale for specific changes are summarized below: Sections 4.2.4.1 and 5.2 and Appendices C and D were updated to clarify and streamline verification test requirements for hydrogen discharges from the vehicle. See Appendices C and D for detailed discussion of issues and recommended verification procedures. Sections 4.2.4.2 and 4.2.5 and Appendix E were changed to clarify guidance with regard to locating hydrogen storage systems within passenger, luggage, and cargo compartments to ensure that discharges from vents and Pressure Relief Devices (PRDs) are properly managed and directed. Section 4.2.6 was modified and the new Appendix F was added to ensure that either the vehicle cannot be moved while the fueling nozzle is connected or the fueling receptacle is properly installed, protected, and secured. Sections 4.2.6, 4.7, and 5.1 were updated to clarify fuel system labeling requirements and harmonize with vehicle badging requirements in SAE J2990 for emergency responders. Sections 4.2.7, 4.4.3, 4.4.3.1, 6, and 7.2 were re-worded to clarify previously-defined issues and guidance. Section 4.4.3 and subordinate subsections were revised to account for Y-capacitors in high voltage circuits and their effect on body current if the high DC and AC voltage circuits are touched. Section 5.2.2 and Appendix C was changed to extend allowable discharge scaling to smaller (micro) vehicles and not just larger vehicles such as buses. Clarifications to the analytical bases of requirements were also made. Appendix A was modified to correct post-crash formulas, improve the explanations, and provide an alternative approach for calculating the mass leakage rate. Appendix E was also modified to clarify guidance with regard to using Pressure Relief Devices (PRDs) in series.