Use of HFR based cathode inlet RH model compared to sensor feedback to determine an incurred water vapor transfer unit and use for a diagnostic code and message

摘要

A system and method for determining whether there is a crossover leak or other fault in a WVT unit that humidifies the cathode inlet airflow at a fuel cell stack in a fuel cell system. The fuel cell system includes an HFR circuit that determines the humidity level of the membranes in the fuel cell stack, and an RH sensor that measures the relative humidity of the airflow to the cathode side of the fuel cell stack. The HFR moisture calculation is compared with the RH measurements from the RH sensor, and if the difference between the two RH values is greater than a predetermined calibration value, the system may determine that the WVT unit is down and waiting or must be replaced.