Alternating current generator charging based on marginal fuel cost

摘要

Method and systems are provided for, in response to a state of charge (SOC) of a vehicle battery increasing above a threshold SOC, reducing an alternator charging based on one or more of a spark timing, an engine speed, an air-fuel ratio, and an engine load. In this way, fuel consumption may be reduced while maintaining a battery SOC for operation of front-end accessories may be achieved, and fuel consumption may be reduced during aggressive vehicle driving conditions such has high engine loads near transmission downshift thresholds and high engine speeds.