Patent ID: 8022674

Claim:
A method for controlling a state of charge in a hybrid electric vehicle battery, comprising: sensing a battery state of charge in a hybrid electric vehicle battery, the battery being operable to provide energy to propel a vehicle; accessing an upper state of charge limit of the hybrid vehicle battery, wherein the upper state of charge limit is from about 60% to about 90% of a capacity of the hybrid electric vehicle battery; accessing a lower state of charge limit of the hybrid vehicle battery, wherein the lower state of charge limit is from about 10% to about 40% of the capacity of the hybrid electric vehicle battery, the upper and lower limit defining a state of charge range of the hybrid vehicle battery; storing a target state of charge value of the hybrid vehicle battery which has been set at less than the midpoint of the state of charge range, wherein the target state of charge value is kept at that level independent of predicted vehicle driving conditions; and regulating the battery state of charge based upon the target state of charge value and the upper and lower limits.