METHOD FOR DIAGNOSING THE OPERATIONAL STATE OF A VARIABLE VALVE ACTUATION (VVA) DEVICE USING A KNOCK SIGNAL

摘要

A method for determining whether a variable valve actuation (VVA) device or subsystem is operating in an improper mode of operation is performed in real-time by an embedded engine or powertrain controller configured to monitor and evaluate an already-available knock sensor output signal. The knock sensor output is captured during a predefined sampling window, defined to include a valve closing event when the VVA device is operating in a proper mode. The captured knock sensor output signal is processed to detect the presence (or absence) of a valve closing event. The absence of a valve closing event when one is expected is indicative of a malfunctioning VVA device.