Gm Global Technolgoy Operations, Inc.

Thomas Weispfenning

Oliver Maier

Peter Willimowski

Jurgen Thyroff

Rolf Isermann

Sascha Schaefer

A thermal sub-system for a fuel cell system that employs an algorithm using feed-forward control. The algorithm calculates a Reynolds number based on the velocity of the cooling fluid, a diameter of a coolant loop pipe and a kinematic viscosity (temperature) of a cooling fluid. The algorithm also uses a pressure loss number based on the Reynolds number and a position of a by-pass valve. The algorithm also defines a pressure loss value based on the pressure loss number, the density of the cooling fluid and the velocity of the cooling fluid. The algorithm then calculates a delivery head value based on the pressure loss value, the fluid density and a gravitational acceleration. The algorithm then uses the delivery head value and a predetermined set-point value of the volume flow to determine a desired pump speed based on the current operating parameters of the system.

Feedforward control of the volume flow in a hydraulic system

A fuel cell system for generating a hydrogen test pulse includes a fuel cell stack having an anode inlet in fluid communication with a hydrogen source via a fuel spending line, a cathode inlet in fluid communication with an oxidant source, and an anode outlet and a cathode outlet in fluid communication with an exhaust line. An electric pressure regulator is in fluid communication with the fuel spending line. An overpressure valve is in fluid communication with an overpressure line, which is in fluid communication with the fuel spending line between the electric pressure regulator and the fuel cell stack. A hydrogen sensor is in communication with the exhaust line, and is configured to measure the hydrogen test pulse.

Method to generate H2-exhaust sensor test pulse using electrically controlled pressure regulator

A method and system for controlling a pressure regulator in a gas storage system using a pressure switch as a pressure measurement device. A controller uses supply pressure data and gas flow demand data to compute a feed-forward control term, and uses data from a pressure sensor downstream of the pressure regulator to compute a feedback control term. During normal operation, with pressure downstream of the regulator oscillating about a set point pressure, on-time and off-time periods of a pressure switch are monitored, and an adaptive control term is computed which balances on-time and off-time. If the pressure sensor fails, excessive switch on-time or off-time will be detected; in response to this, the feedback control term is disregarded, and an adaptive control term is computed which aims to restore balanced on-time and off-time of the switch, thus indicating that the actual pressure is oscillating about the set point.

Redundant adaptive algorithm for electrical pressure regulated high pressure tank systems

A system and method for drying a fuel cell stack after stack shutdown. In one embodiment, a cooling fluid is pumped through the fuel cell stack after the system is shutdown to use the heat still available in the cooling fluid immediately after shutdown to provide thermal equilibrium in the stack. In another embodiment, the heated cooling fluid still available immediately after system shutdown is sent through a cathode input gas heat exchanger so that drying air from the system compressor is heated by the cooling fluid before it enters the stack. In another embodiment, a separate heat exchanger is provided that receives the drying gas prior to it being sent into the fuel cell stack.

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Ober-Ramstadt, Germany

Thomas Weispfenning