FIRING FRACTION MANAGEMENT IN SKIP FIRE ENGINE CONTROL

Engine controllers and methods are described that facilitate skip fire control of an internal combustion engine. An engine controller determines a skip fire firing fraction and (as appropriate) associated engine settings that are suitable for delivering a requested output. The engine controller selects an operational firing fraction from a set of available firing fractions. A firing controller then directs cylinder firings in a skip fire manner that delivers the selected operational firing fraction. The firing controller includes an accumulator that helps smooth transitions between different firing fractions.