This is a request for some revised and clarified wordings for parameters related to fuel cells.
In 23188 Hydrogen supply request, we see a potential ambiguity between ‘00b’ and ‘11b.’ Both states may not require immediate action. To improve clarity, we recommend stating that ‘Hydrogen is required to be OFF’ in the case of '00b.
In 23200 Fuel Cell System High Voltage Power Supply Interlock Command: The enum '00b, which states that the ‘Fuel cell system is not requesting the high voltage power supply to be on, but the external environment can choose to turn on the high voltage supply if needed.’, seems quite similar to the state ‘11b,’ which means ‘Don’t care/Take no action.’ This is because both states might not lead to any immediate action.
To prevent confusion, we suggest that, in the case of ‘00b,’ it should indicate that the fuel cell system is actively asking for the high voltage power supply to be turned OFF.
To avoid any risk of confusion we propose to clarify if the measured hydrogen concentration refers to absolute concentration or relative to EGLI. This applies to SPNs 21336, 21337, 21338 and 23397.
20240408HL_2 (Lundkvist) - Revised Wording of Hydrogen and Fuel Cell Parameters.xlsm (461.8 KB)