Method for adjusting battery power limits in a hybrid electric vehicle to provide consistent launch characteristics

A control algorithm for implementing a wide limit mode (WLM) of operation in a vehicle comprising an energy storage system having a rechargeable battery, the battery having at least one monitored battery power parameter, at least one parametric discharge power limit and a closed-loop controller operating through the execution of a plurality of control loops and adapted to determine whether the WLM is active or not active, the controller having a timer and a counter that are adapted to count time intervals associated with the implementation of the WLM by incrementing a count when the WLM is active and decrementing the count or maintaining a zero count when the WLM is not active;

• comprising the steps of:
• (1) determining a WLM ratio using a vehicle speed input and a vehicle torque command input;
• (2) initializing the timer, counter and a control loop, wherein the WLM ratio is set to zero for the first control loop;
• (3) determining whether the WLM is active and whether the timer is expired, and if the WLM is active and the timer is not expired, proceeding to step (4), otherwise, proceeding to step (5);
• (4) incrementing the timer and counter and proceeding to step (8);
• (5) setting the WLM ratio to zero;
• (6) decrementing the timer and counter and proceeding to step (7);
• (7) setting a lower limit for the counter and proceeding to step (8);
• (8) determining the amount of a WLM discharge power limit shift that is based on the WLM ratio;
• (9) applying the WLM discharge power limit shift to at least one parametric discharge power limit;
• and
• (10) determining whether the control loop is the last control loop, wherein if the control loop is the final control loop, and if yes, ending the algorithm, and if no, iterating the algorithm for another control loop by returning to step (1).