Method for compensating for accessory loading

摘要

An internal combustion engine includes an advanced vehicle system controller (VSC) that calculates a total power demand to meet a driver wheel power demand plus any accessory loads and independently schedules an engine speed and load operating point to meet the total power demand. A reduction in available engine brake power that is not associated with a driver input, and would ordinarily cause the VSC to respond by raising engine speed, is detected. The driver wheel power demand is reduced to compensate for the reduction in available engine brake power such that the VSC does not need to raise engine speed to meet the driver wheel power demand. A magnitude of the reduction may be determined according to a calibration map to allow a trade off to be made between driveability and noise, vibration, and harshness.