EN 17127 is based on SAE J2601 – Filling Protocols for Light Surface Hydrogen Gas Vehicles in the filling process.  The SAE J2601 standard defines the protocol and process limits for refuelling hydrogen into vehicles. The process limits (e.g., fuel delivery temperature, maximum flow rate, final pressure, and rate of reaching it) are dependent on external factors such as ambient temperature, fuel delivery temperature, and the pressure of the tank into which the hydrogen will be filled. The SAE J2601 standard defines standard protocols for hydrogen refuelling. These protocols are either based on a lookup table that uses a fixed rate of pressure rise in the container, or on the use of a dynamic rate of pressure rise formula. In this case, the filling rate is calculated continuously during the filling process. When using the lookup table protocol, the hydrogen pressure value reached at the end of the filling process is known, in contrast, the protocol using the pressure rise rate formula defines the maximum hydrogen pressure value reached during the filling process. Both protocols allow hydrogen filling with or without communication (between the filling device and the vehicle). For filling with communication, SAE J2799 – Hardware and Software for Communication between Hydrogen Surface Vehicles and Stations must be used in addition to SAE J2601. A critical factor in the performance of hydrogen filling is the ability of the HFS to achieve the desired temperature of the hydrogen delivered. Depending on the temperature, the delivered hydrogen is divided into three categories, denoted by the letter, "T": T40, T30, T20. The T40 category is the coldest. The SAE J2601 standard defines filling protocols for pressure classes 350 bar and 700 bar and three categories of fuel delivery temperatures (-40 °C, -30 °C, -20 °C). It also defines two sizes of hydrogen storage systems. The first system operates with both 350 and 700 bar pressures and its volume is 49.7l - 248.6l and the second operates only with 700bar pressure and its volume is 248.6l and above. [16]

Parameter

Limit

Minimum hydrogen temperature

-40 °C

Maximum hydrogen temperature

85 °C

Minimum pressure in the dispenser

0,5 MPa

Maximum pressure in the dispenser

87,5 MPa

Maximum flow rate

60 g/sec.

 

SAE J2799 – Hardware and software for communication between hydrogen surface vehicles and stations.

This standard specifies the communication hardware and software requirements for hydrogen fueling of hydrogen surface vehicles (HSVs) such as fuel cell vehicles, but can also be potentially applied to heavy duty vehicles (e.g. buses) and industrial trucks (e.g. forklifts) with a compressed hydrogen storage tank. It includes a description of the communication hardware and protocol that can be used to refuel the HSV. The intent of this standard is to enable the harmonised development and implementation of interfaces for hydrogen refuelling.