VARIABLE DISPLACEMENT ENGINE DIAGNOSTICS

摘要

Methods and systems are provided for monitoring cylinder valve deactivation in an engine operating with a plurality of cylinder valves. One example method comprises indicating valve degradation based on an indication of manifold pressure over a plurality of immediately successive induction events of the engine, the indication responsive to increases and decreases in the indication of manifold pressure correlated to the induction events of engine cylinders and further correlated to whether cylinders are commanded to be activated or deactivated.