Gm Global Technolgoy Operations, Inc.

Tayoung Choi

Sriram Ganapathy

Anthony H Heap

Krunal P Patel

Balasubramanian Lakshmanan

John P Salvador

Manish Sinha

Darrell W Burleigh

David A Arthur

Dongmei Chen

David R Savage

Jaehak Jung

Steven M Hessell

Pamela M Vecasey

A powertrain system employing multiple propulsion torque actuators is described. A method for controlling the powertrain system includes interpreting a driver request, including determining a driver torque request and a regenerative braking request based upon driver inputs to an accelerator pedal and a brake pedal. A desired request is determined based upon the driver torque request and the regenerative braking request. Torque limits for the powertrain system are coordinated based upon the desired request, the driver torque request, and a previous driver torque request to determine upper and lower output torque limits, and the upper and lower output torque limits are combined with system constraints to generate a final torque request. The final torque request is employed to determine torque commands for the propulsion torque actuators, and the propulsion torque actuators are controlled based upon the torque commands for the propulsion torque actuators.

Method to coordinate propulsion torque actuators through torque limits

A method for controlling a powertrain of a vehicle includes calculating, via a controller, an optimal torque target for the powertrain as a function of system limits of the vehicle. The method includes commanding, via transmission of an output torque signal, an actual output torque of the powertrain to pursue or follow the calculated optimal torque target during a steady-state torque request condition. Additionally, the method includes detecting a predetermined vehicle event during the steady-state torque request condition, and shaping the output torque signal via the controller. A variable gain factor may be used in response to detection of the predetermined vehicle event to allow the output torque signal to temporarily deviate from the calculated optimal torque target during the steady-state torque request condition. A powertrain has an engine, an electric machine, and a controller programmed to execute the method.

Powertrain and control method with selective pursuit of optimal torque targets

A system and method for determining when to trigger reconditioning of a fuel cell stack and when to disable the reconditioning of the fuel cell stack. In one embodiment, the stack reconditioning is triggered when a maximum stack power estimation falls below a first predetermined power threshold. The reconditioning of the stack can be disabled so it is not performed when the trigger occurs if the reconditioning process does not raise the maximum power estimation above a second predetermined power threshold or the time from one reconditioning trigger to a next reconditioning trigger is less than a predetermined time threshold, or both.

Method to automatically enable/disable stack reconditioning procedure based on fuel cell stack parameter estimation

A system and method for detecting a low performing cell in a fuel cell stack using measured cell voltages. The method includes determining that the fuel cell stack is running, the stack coolant temperature is above a certain temperature and the stack current density is within a relatively low power range. The method further includes calculating the average cell voltage, and determining whether the difference between the average cell voltage and the minimum cell voltage is greater than a predetermined threshold. If the difference between the average cell voltage and the minimum cell voltage is greater than the predetermined threshold and the minimum cell voltage is less than another predetermined threshold, then the method increments a low performing cell timer. A ratio of the low performing cell timer and a system run timer is calculated to identify a low performing cell.

Method to improve reliability of a fuel cell system using low performance cell detection at low power operation

A system and method for providing nearly instantaneous power in a fuel cell vehicle. The method includes monitoring the brake pedal angle and the accelerator pedal angle of the vehicle, and if the vehicle driver is pressing both the brake pedal and the accelerator pedal at the same time and the vehicle is in a drive gear, activating a heel and toe mode. When the heel and toe mode is activated, the speed of a cathode compressor is increased to a predetermined speed set-point, which is higher than the normal compressor speed for the pedal position. Thus, when the vehicle brake is removed, the compressor speed is high enough to provide enough air to the cathode, so that the stack can generate nearly immediate power.

Heel and toe driving on fuel cell vehicle

A system and method for maintaining the voltage of fuel cells in the fuel cell stack below a predetermined maximum voltage. The method determines a desired voltage set-point value that defines a predetermined maximum fuel cell voltage value and uses the voltage set-point value and an average fuel cell voltage to generate an error value there-between. The method generates a minimum gross power prediction value using the modified voltage set-point value to prevent the fuel cell voltages from going above the predetermined maximum fuel cell voltage value and generating a supplemental power value based on the minimum gross power prediction value and the error value to determine how much power needs to be drawn from the stack to maintain the fuel cell voltage below the predetermined maximum voltage value. The method uses the supplemental power value to charge the battery or operate an auxiliary load coupled to the stack.

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Rochester, NY, United States of America

Tayoung Choi