SAE J2601/4_202410

SAE J2601-4 establishes process limits for ambient temperature hydrogen fueling of light-duty automotive vehicles, passenger cars, and trucks that use a compressed hydrogen storage system (CHSS) that meets SAE J2579, where ambient temperature hydrogen fueling is defined as a fueling event where the fuel delivery temperature is greater (e.g., warmer) than the precooled requirements of SAE J2601. Table 1 depicts the scope of SAE J2601-4 and potential work items for future revisions within this or other documents of the SAE J2601 series. SAE J2601 includes protocols that are applicable for two pressure classes (35 MPa and 70 MPa), three fuel delivery temperature categories (-40 °C, -30 °C, and -20 °C) and CHSS sizes from 49.7 to 248.6 L. Future versions of SAE J2601 may incorporate warmer fuel delivery temperatures (-10 °C and ambient) and smaller compressed hydrogen storage systems for motorcycles and other light-duty applications. Fueling protocols should be developed based on a set of key assumptions described in Section 7 and Appendix A of J2601. These assumptions should be carefully considered in the development and implementation of an onboard CHSS. In particular, hydrogen storage systems with properties that do not fall within the parameters in Table A3 of SAE J2601 should be further evaluated with protocols developed based on the process limits described in this Technical Information Report (TIR). For fueling with communications, this TIR is to be used in conjunction with SAE J2799. This document focuses on the fueling protocol and the equipment necessary to implement the fueling protocol properly. Other requirements may be necessary to operate the station in a proper manner. The Technical Information Report, J2601, issued March 2010 (2010 TIR), provided guidance for fueling vehicles with and without precooling of the dispensed hydrogen. The 2010 TIR also highlighted a potential issue with higher-than-expected CHSS temperatures that could arise if a vehicle were to fuel at one station immediately followed by a higher pressure fueling at a second station, also known as a subsequent fill. Ongoing revisions of J2601 address subsequent fill issues for stations with precooling and eliminate the fueling protocol for stations that do not cool the hydrogen gas to the levels defined by the T20, T30, or T40 protocols.