Method and apparatus for controlling the engine idle speed in a hybrid electric vehicle

A method for controlling the idle speed of an engine within a hybrid electric vehicle including a generator having a rotor assembly which is operatively coupled to an engine, said method comprising the steps of:

• determining whether a first set of vehicle idle entry conditions are met, wherein said first set of vehicle idle entry conditions comprises whether the vehicle is below a predetermined maximum idle speed and whether an accelerator pedal is below a predetermined minimum pedal position;
• scheduling a desired engine brake torque and selectively activating a vehicle system controller to control said generator to schedule a desired engine speed and produce a first desired effect when a first set of operating conditions is present, wherein said first set of operating conditions is selected from the group consisting of a low battery state of charge, a low climate control vacuum level, a low brake system reservoir vacuum level, a low powertrain mount vacuum level, a high fuel tank pressure, the existence of a minimum time period since a last vapor canister purging, the existence of current vapor canister purging, the existence of a learned adaptive fuel table for the current driving mode, a low engine temperature, a low catalyst temperature, and the state of activation of an air conditioning switch;
• selectively activating an engine controller to control engine idle speed when a second set of operating conditions is present;
• turning off the engine when said first set of conditions is not present and when the engine has been in a current vehicle idle mode for a predetermined amount of time, otherwise maintaining said current vehicle idle mode.