Gm Global Technolgoy Operations, Inc.

Martin Monroe Hoch

James S Siepierski

Eric L Thompson

Stephen Farris

Donald D Stoltman

Glenn William Skala

Benno Andreas-Schott

Mark A Meltser

Barbara S Moore

Julie A Stuart

A three-way diverter assembly with a contoured valve is provided. The three-way diverter assembly includes a housing having a first inlet, a second inlet, a first outlet, and a second outlet. The first inlet and the second inlet are adapted to receive a fluid. The contoured valve is disposed in the housing adjacent the first inlet. The contoured valve is rotatable about an axis from a first positional limit to a second positional limit, and to a plurality of positions therebetween. Fuel cell systems having the three-way diverter assembly for regulating temperature and humidity of a fuel cell stack are also provided.

Three-way diverter assembly for a fuel cell system

Systems of checking thermal-induced circulation of a coolant in a fuel cell stack are disclosed. The system includes coolant inlet and outlet lines extending from a fuel cell stack. A pump and a radiator are confluently connected to the coolant inlet and coolant outlet lines. In one embodiment, a valve (either check type or automatic type) is provided in the coolant outlet line at the bottom of the fuel cell stack to prevent the flow of cold coolant from the coolant outlet line into the fuel cell stack upon start-up of the fuel cell stack. In another embodiment, a valve (either one-way flow control type or automatic type) is provided in the coolant inlet line at the top of the fuel cell stack. A method of checking thermal-induced circulation of a coolant in a fuel cell stack is also disclosed.

Circulation check for fuel cell coolant

A system and method for controlling the flow of a cooling fluid through a fuel cell stack during cold system start-up. A pump pumps the cooling fluid through the stack. At cold start-up, the pump is selectively turned on and off in a pulsed manner based on the temperature, cooling fluid volume, stack output power and other factors so that a minimal amount of the cold cooling fluid is introduced into the stack. By selectively controlling the duty cycle and the frequency of the pump pulsing, the reaction temperature will heat the cooling fluid, but the influence of the cold cooling fluid on the stack output power will be minimized. In an alternate embodiment, an electric heater is positioned in the inlet manifold, so that the cooling fluid is heated in the inlet manifold during the times that the pump is off.

Pulsed coolant control for improved stack cold starting

A reformer fuel feed stream in fuel cell power system is catalytically reacted into a reformate stream for a fuel cell stack by adjusting fuel supply throughput according to a predefined throughput ramp when a time derivative and the current demand for the fuel cell deviates from zero by more than an acceleration threshold value. The fuel cell power system is of special value when deployed on a vehicle where the load command is derived from the accelerator pedal of the vehicle.

Gasoline fuel cell power system transient control

Process for improving the efficiency of a fuel cell system having a liquid coolant and a pump circulating the coolant through the fuel cell and a heat exchanger that extracts heat from the coolant. Improved efficiency is achieved by intermittently shutting off the pump when the fuel cell is operating at less than 25% of its &ldquo;full power&rdquo; design point.

Intermittent cooling of fuel cell

A fuel cell system including a dry compressor for pressurizing air supplied to the cathode side of the fuel cell. An injector sprays a controlled amount of water on to the compressor's rotor(s) to improve the energy efficiency of the compressor. The amount of water sprayed out the rotor(s) is controlled relative to the mass flow rate of air inputted to the compressor.

Water injected fuel cell system compressor

Method for controlling the supply of air to a PROX reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference therebetween correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference.

Controlled CO preferential oxidation

The reciprocating plunger reciprocable in the pump cylinder of a distributor type diesel fuel injection pump is helically splined to an index ratchet gear that is also operatively associated with a pawl detent whereby the index ratchet gear is rotatable in only one direction. The plunger has a discharge slot on its outer peripheral surface which registers with one of the plural discharge ports opening from the pump cylinder and the plunger controls the covering and uncovering of a fuel inlet port to the pump cylinder. Upon a pump stroke of the plunger, the index ratchet gear is rotated so that the next adjacent tooth is brought into alignment with the pawl detent to then prevent its rotation in the opposite direction during the suction stroke of the plunger. With the index ratchet gear thus fixed, the plunger is thus rotated on the suction stroke so as to align the discharge slot with the next adjacent discharge port. A normally open solenoid valve controls spill flow from the pump cylinder during a pump stroke of the plunger so as to control the start and end of fuel injection.

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Webster, NY, United States of America

Martin Monroe Hoch