SAE taskforce completes two technical standards on hydrogen refueling; harmonizing the global infrastructure
To support the impending roll-out of hydrogen fueling infrastructure and Fuel Cell Electric Vehicles (FCEV), SAE International’s Fuel Cell Standards Taskforce has completed two technical standards: SAE J2601, “Fueling Protocols for Light Duty Gaseous Hydrogen Surface Vehicles”; and SAE J2799, “Hydrogen Surface Vehicle to Station Hardware and Software”. The standards have been created to harmonize hydrogen fueling worldwide for both 35 MPa and 70 MPa pressures.
J2601. SAE J2601 (also with J2799) fuels fuel cell vehicle hydrogen storage systems quickly to a high state of charge (SOC) without violating the storage system operating limits, explained Jesse Schneider, Sponsor of both Standards SAE J2601 & J2799, in a presentation at the SAE 2014 Hybrid & Electric Vehicle Technologies Symposium earlier this year. SAE J2601 defines parameters for a hydrogen fueling experience similar to conventional fueling and is considered one of the key standards required for the commercialization of fuel cell vehicles and hydrogen stations.
The SAE J2601 Standard enables safe, full hydrogen fast-fueling, 3-5 minutes, for all light duty FCEVs, including models with a range of 300 or more miles (500km+). Obtaining extended driving ranges with hydrogen fueling is accomplished by compressing hydrogen to 70 MPa (or H70).
J2601 establishes safety limits and performance requirements for gaseous hydrogen fuel dispensers. The criteria include maximum fuel temperature at the dispenser nozzle, the maximum fuel flow rate, the maximum rate of pressure increase and other performance criteria based on the cooling capability of the station’s dispenser.
This SAE standard hydrogen fueling protocol uses a look-up table approach and an average pressure ramp rate that has a consistent pressure rise which gives consistent fueling times for all vehicles. The SAE J2601 Standard fueling tables allow a simple control where the dispenser stops at a target pressure, based on ambient temperature and initial fuel pressure, giving a consistent hydrogen fueling (with a high state of charge).
This protocol termed the “J2601 standard fueling” method has been validated in the laboratory with real automaker hydrogen storage tanks under extreme conditions and also in the field at public stations on two continents with multiple automaker FCEVs. The data confirming this hydrogen fueling methodology—from automakers and hydrogen fuel providers—has been documented in a 2014 SAE World Congress Technical Paper (2014-01-1833).
|J2601 lookup table approach. Click to enlarge.|
The speed of hydrogen fueling is directly related to the amount of cooling that the dispenser allows, to offset the heat of compression. Therefore, a H70-T40 fueling dispenser enables this fast-fueling by providing hydrogen fuel at -40 °C to the fuel cell vehicle.
|“Hydrogen Fueling is the only ZEV infrastructure technology proven to achieve ‘same as today’s’ fuel delivery rates and equivalent driving range for all vehicle segments.”|
—Jesse Schneider, at SAE 2014 Hybrid & Electric Vehicle Technologies Symposium
The J2601 Standard document applies to light duty vehicle fueling for vehicles with storage capacity from 2 to 10 kg for 70 MPa and 2.4 to 6 kg for 35 MPa. Separate J2601 documents will cover fueling heavy-duty vehicles and forklifts.
SAE J2601 has a number of updates from the previous Technical Information Report (TIR) including allowing “top-off fueling” and “Cold Dispenser fueling” as well as numerous improvements for robust operation at the hydrogen dispenser.
|J2799 wireless FCEV to H2 station standard. Click to enlarge.|
J2799. SAE J2799 standardizes wireless communications between the FCEV and the hydrogen station. The advantage of using this optional communications standard, when coupled with J2601 fueling, is that the state of charge can be further improved to 95-100% SOC allowing for slightly more driving range than without communications.
Recognizing innovation, SAE J2601 has a non-standard appendix describing the MC Default Fill Protocol. This development protocol is currently being tested in the field and may be included in future updates to SAE J2601. (Earlier post.)
The SAE Standards J2601 and J2799 are currently under final review by SAE management and are to be published in the near future.
Jesse Schneider et al. “Validation and Sensitivity Studies for SAE J2601, the Light Duty Vehicle Hydrogen Fueling Standard” (SAE 2014-01-1990)