초록 ▼

A PEM fuel cell system includes a PEM fuel cell that has an input and output port each for fuel or reformate, process air and coolant. A predetermined fraction of volume of moistened exhaust air leaving the air output port of the fuel cell is diverted back and combined with fresh, air at ambient tem

A PEM fuel cell system includes a PEM fuel cell that has an input and output port each for fuel or reformate, process air and coolant. A predetermined fraction of volume of moistened exhaust air leaving the air output port of the fuel cell is diverted back and combined with fresh, air at ambient temperature entering the air input port of the PEM fuel cell to maintain water balance in the fuel cell at high ambient operating temperatures. The recycle-to-air vent ratio is controlled by a processor which adjusts the recycle flow based on the ambient temperature and the power level of the fuel cell.

대표청구항 ▼

[ What is claimed is:] [1.] A PEM fuel cell system comprising:a PEM fuel cell having a coolant input port and coolant output port, a fuel input port and fuel output port, and an air input port and air output port, the air input port to be coupled to a source of fresh air at about ambient temperature

[ What is claimed is:] [1.] A PEM fuel cell system comprising:a PEM fuel cell having a coolant input port and coolant output port, a fuel input port and fuel output port, and an air input port and air output port, the air input port to be coupled to a source of fresh air at about ambient temperature;an adjustable airflow splitter having an input port, first and second output ports, and a control port for adjusting a ratio of volume of air exiting the first output port of the airflow splitter to a volume of air exiting the second output port (recycle-to-air vent ratio), the input port of the airflow splitter being coupled to the air output port of the PEM fuel cell, the first output port of the splitter communicating with the air input port of the PEM fuel cell;an ambient temperature measuring device for generating a temperature signal;an electrical power measuring device coupled to electrodes of the fuel cell for generating a power signal indicative of the percentage of rated power being generated by the fuel cell; anda processor having inputs coupled to the temperature measuring device, the electrical power measuring device and an output coupled to the control input of the airflow splitter, the processor controlling the airflow splitter for adjusting the recycle-to-air vent ratio of the fuel cell system to a predetermined value to maintain an overall water balance in the fuel cell system at the sensed ambient operating temperature and power level.