Fuel cell power systems have been proposed as a clean, efficient and environmentally responsible power source for electric vehicles and various other applications. One type of fuel cell power system employs use of a proton exchange membrane (PEM) to catalytically facilitate a reaction of fuels (such as hydrogen) and oxidants (such as air or oxygen) into electricity. Typically, the fuel cell power system has more than one fuel cell that includes an anode and a cathode with the PEM therebetween. The anode receives the hydrogen gas and the cathode receives the oxygen. The hydrogen gas is ionized in the anode to generate free hydrogen ions and electrons. The hydrogen ions pass through the electrolyte to the cathode. The hydrogen ions react with the oxygen and the electrons in the cathode to generate water as a by-product. The electrons from the anode cannot pass through the PEM, and are instead directed through a load to perform work before being sent to the cathode. The work acts to operate the vehicle. Many fuels cells are combined in a fuel cell stack to generate the desired power.
The hydrogen gas for the fuel cell power system can be processed separate from the vehicle and stored at a filling station and the like. The hydrogen gas may be transferred from the filling station to a high pressure vessel or container on the vehicle to supply the desired hydrogen gas to the fuel cell system as needed. The high pressure vessels are typically classified into one of four types: a Type I vessel having an all-metal construction; a Type II having a metal lined construction with a fiberglass hoop wrap; a Type III having a metal lined construction with a composite full wrap; and a Type IV having a plastic lined construction with a composite full wrap.
Current fueling operations for fuel cell vehicles are controlled (e.g. stopped) by the fueling station. Conventional vehicles and fuel cell systems are not equipped to control a delivery of a fuel from an outside source. For example, when a hydrogen storage system is “out of spec” (e.g. a temperature is beyond a suitable range) during a fueling operation, the vehicle could not interrupt the fueling independently from the filling station.
Certain systems include a valve that can be closed in order to prevent the delivery of the fuel into the system. However, a differential pressure can build across a closed valve and actuating a valve under high differential pressure minimizes an operational life of the valve.
It would be desirable to develop a fill control system having a valve to control a fueling operation without shutting a fuel line.