Method of undervoltage protection during engine cranking
First Claim
1. A method for controlling the cranking of an engine of a vehicle powertrain system having a rechargeable energy storage system that is adapted to provide clectric power to an electric machine for cranking the engine, comprising the steps of:
- initiating an engine crank state from an engine off state;
controlling an exit from the engine crank state as a function of an output voltage of the energy storage system to the electric machine during the crank state, wherein if the output voltage is less than a crank undervoltage threshold for a predetermined crank time, the crank state is exited and the system transitions from the engine crank state to the engine off state;
incrementing a counter for each such exit from the engine crank state to establish an engine crank count; and
if the engine crank count does not exceed an engine crank count limit, repeating the preceding steps.
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Accused Products
Abstract
A method for controlling the cranking of an engine of a vehicle powertrain system having a rechargeable energy storage system that is adapted to provide electric power to an electric machine, wherein the system is adapted to exit from the engine crank state as a function of an output voltage of the energy storage system to the electric machine during the crank state, if the output voltage is less than a crank undervoltage threshold for a predetermined crank time. According to the method, the crank undervoltage threshold is a function of the number of failed start attempts, generally decreasing as a function of the number of failed start attempts. The predetermined crank time is a function of a magnitude of a difference between the output voltage and the crank undervoltage threshold.
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Citations
20 Claims
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1. A method for controlling the cranking of an engine of a vehicle powertrain system having a rechargeable energy storage system that is adapted to provide clectric power to an electric machine for cranking the engine, comprising the steps of:
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initiating an engine crank state from an engine off state; controlling an exit from the engine crank state as a function of an output voltage of the energy storage system to the electric machine during the crank state, wherein if the output voltage is less than a crank undervoltage threshold for a predetermined crank time, the crank state is exited and the system transitions from the engine crank state to the engine off state; incrementing a counter for each such exit from the engine crank state to establish an engine crank count; and if the engine crank count does not exceed an engine crank count limit, repeating the preceding steps. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for controlling the cranking of an engine of a vehicle powertrain system having a rechargeable energy storage system that is adapted to provide electric power to an electric machine for cranking the engine in response to the control actions of a controller, the method adapted for execution as code in a computer controller, comprising the steps of:
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initiating an engine crank state from an engine off state; controlling an exit from the engine crank state as a function of an output voltage of the energy storage system to the electric machine during the crank state, wherein if the output voltage is less than a crank undervoltage threshold for a predetermined crank time, the crank state is exited and the system transitions from the engine crank state to the engine off state; incrementing a counter for each such exit from the engine crank state to establish an engine crank count; if the engine crank count does not exceed an engine crank count limit, repeating the preceding steps; and if the engine crank count exceeds the engine crank count limit, setting a fault in the controller which disallows subsequent initiating of the engine crank state until the fault is cleared. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification