Tuesday, October 2, 2007

United States Patent 7,277,781
Cawthorne , et al. October 2, 2007

Method of under voltage protection during engine cranking


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.

Inventors: Cawthorne; William R. (Milford, MI), Nitz; Larry T. (Brighton, MI)
Assignee: General Motors Corporation (Detroit, MI)
DaimlerChrysler AG (Stuttgart, DE)
DaimlerChrysler Corporation (Auburn Hills, MI)
Appl. No.: 10/845,999
Filed: May 14, 2004

Current U.S. Class: 701/22 ; 180/65.2; 701/113
Current International Class: G06F 17/00 (20060101)

References Cited [Referenced By]

U.S. Patent Documents

October 2003

December 2002
Theisen et al.

Foreign Patent Documents

WO 03/049965
Jun., 2003

Primary Examiner: Zanelli; Michael J.

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