Gm Global Technolgoy Operations, Inc.

Jun Cai

Sergio E Garcia

Manish Sinha

Steven R Falta

Seth E Lerner

Stephen D Pace

Bruce Jeffrey Clingerman

John P Salvador

Abdullah Basar Alp

Steven D Burch

Matthew C Kirklin

Sriram Ganapathy

Daniel C Di Fiore

Aaron R Rogahn

Andrew J Maslyn

Akbar Chowdhury

Joseph A Berg

Joseph Nicholas Lovria

David R Savage

Jaehak Jung

Loren Devries

James K Leary

Joseph C Gerzseny

Elizabeth Dicocco

Carol A Galskoy

William S Marley

Joseph Castelluccio

Daniel W Smith

A fuel cell system for a vehicle or other system includes a fuel cell stack, a DC-DC boost converter, and a controller. The stack has a plurality of fuel cells and a stack voltage. The controller regulates the stack voltage during start-up of the fuel cell stack via the boost converter, and is programmed with a plurality of calibrated voltage profiles each having a corresponding magnitude and rate of change. The controller is configured to execute a method which includes detecting an air start of the fuel cell stack in response to a requested start-up of the fuel cell stack. The controller then enforces the stack voltage to the predetermined voltage profiles during an actual start-up of the fuel cell stack, doing so via regulation of the boost converter and using the plurality of calibrated voltage profiles.

Fuel cell system start-up using voltage profile control

A fuel cell voltage recovery system includes a fuel cell stack having a fuel cell stack voltage between fuel cell stack terminals which is at a first voltage during normal fuel cell operation. The system also includes a high voltage electrical system operating at a first DC operating voltage that is generally higher than the first voltage of the fuel cell stack. A boost converter in electrical connection with the fuel cell stack and the high voltage electrical system operates in a normal control mode to transfer electrical power from the fuel cell stack to the high voltage electrical system through regulation and control of average stack output current (boost input current) during normal fuel cell operation. The boost converter can also operate in a voltage control mode to lower the fuel cell stack voltage to a second voltage that is lower than the first voltage. A FCS controller controls the operation of the boost converter.

Stack voltage control for recovery mode using boost converter

Systems and methods for detecting and validating a leak in a fuel cell system are presented. In certain embodiments, various fuel cell stack set points may be adjusted such that adequate Hflow data may be obtained to identify and validate an Hleak and/or a location of such a leak. In some embodiments, Hflow data may be obtained by adjusting certain fuel cell system operating parameters under a variety of operating conditions and/or modes and measuring flow data under such various operational conditions.

Systems and methods for detecting leaks in a fuel cell system

A system and method for determining whether a concentration estimation value of hydrogen gas in an anode sub-system of a fuel cell system is within a predetermined threshold of a valid hydrogen gas concentration, and if not, correcting the estimation value. The method includes providing a hydrogen gas concentration sensor value from a virtual sensor and calculating the hydrogen gas concentration estimation value using a gas concentration estimation model. The method also includes determining if a difference between the estimation value and the sensor value is greater than at least one threshold, and if so, causing an extended bleed event to occur that bleeds an anode exhaust gas to force the estimation value to be closer to the sensor value. The method also includes setting a diagnostic if multiple extended bleeds do not cause the estimation value and the sensor value to converge.

Validation and correction of gen 2 anode H2 concentration estimation

A method for shutting down a fuel cell system including operating a fuel cell stack. the method includes providing an increased cathode air flow so as to dry fuel cell membranes in the stack until a first desired level of high frequency resistance is achieved, rehydrating the cell membranes of the stack until a second desired level of high frequency resistance is achieved, and operating the stack with a decreased cathode input relative humidity until a third desired level of high frequency resistance is achieved.

Controls giving &#x2212;25&#xb0; C. freeze start capability to a fuel cell system

A system and method for detecting an anode pressure sensor failure in a fuel cell system. The system and method include a controller that sets an initial minimum anode pressure sensor value and an initial maximum anode pressure sensor value. The controller determines a desired time interval for sampling anode pressure measurements and determines a total number of samples of anode pressure measurements to be collected by the controller from an anode pressure sensor. The controller also compares a pressure difference between the initial or a measured minimum anode pressure and the initial or a measured maximum anode pressure to a predetermined pressure difference threshold and sets a pressure sensor fault if the pressure difference between the initial or measured minimum anode pressure and the initial or maximum anode pressure is less than the predetermined pressure difference threshold.

Extremum seeking algorithm in a variable time interval to detect anode pressure sensor stuck failure in a fuel cell system

A method for determining when to inject hydrogen gas into the anode side of a fuel cell stack associated with a fuel cell vehicle when the vehicle is off. The method includes estimating the concentration of hydrogen gas in the anode side of the fuel cell stack using a gas concentration model and determining if the estimated concentration of hydrogen gas is below a first predetermined threshold. If the estimated hydrogen gas is less than the threshold, then hydrogen gas is injected into the anode side from a hydrogen source. While the hydrogen gas is being injected, the method compares the estimated concentration of the hydrogen gas in the anode side to a desired concentration, and generates an error signal there between. If the error signal is greater than a second predetermined threshold, the algorithm continues to inject the hydrogen into the anode side of the fuel cell stack.

Feedback control of H2 injection during park based on gas concentration model

A system and method for determining a loss of cooling fluid from a thermal sub-system in a fuel cell system. The method includes monitoring current feedback from a high temperature pump that pumps the cooling fluid through a coolant loop. A measured current from the pump is compared to an expected current for the system operating conditions, and if that current is significantly less than what is expected, then it may be as a result of low cooling fluid. If the measured current is less than the expected current for a predetermined period of time, then the system can take mitigating action as a result of a low cooling fluid. Further, if the pump speed is too low to provide an accurate current measurement, then it can be increased if an overflow tank level sensor indicates a low cooling fluid level.

Method to detect gross loss in coolant based on current feedback from the high temperature pump

A system and method for correcting a large fuel cell voltage spread for a split sub-stack fuel cell system. The system includes a hydrogen source that provides hydrogen to each split sub-stack and bleed valves for bleeding the anode side of the sub-stacks. The system also includes a voltage measuring device for measuring the voltage of each cell in the split sub-stacks. The system provides two levels for correcting a large stack voltage spread problem. The first level includes sending fresh hydrogen to the weak sub-stack well before a normal reactive bleed would occur, and the second level includes sending fresh hydrogen to the weak sub-stack and opening the bleed valve of the other sub-stack when the cell voltage spread is close to stack failure.

Anode reactive bleed and injector shift control strategy

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Fairport, NY, United States of America

Jun Cai