Combustion engine airflow management systems and methods

A method of conducting prognosis for an airflow management system for a combustion engine comprising:

• adjusting a throttle body valve position control signal in response to a detected airflow variation;
• monitoring an airflow variation compensation (AVC) value corresponding to a degree of adjustment of the control signal;
• generating a throttle body coking severity metric based on at least a plurality of residual error values and the AVC value;
• and
• executing at least one response action based on the throttle body coking severity metric exceeding a predetermined threshold.

A prognosis system for an engine airflow management system having a mass airflow (MAF) sensor adapted to sense mass flow rate of air passing through an inlet portion, a throttle position sensor (TPS) adapted to sense an opening amount of a throttle body downstream of the inlet portion, and a manifold air pressure (MAP) sensor adapted to sense air pressure at an intake manifold downstream of the throttle body, the prognosis system comprising:

• a controller programmed to
• receive signals from each of a group of sensors including at least the MAF sensor, TPS, and the MAP sensor,
• adjust a throttle body valve position control signal in response to a detected airflow variation,
• generate an airflow variation compensation (AVC) value corresponding to a degree of adjustment of the valve position control signal, and
• store in a memory at least one mathematical model to estimate throttle body valve contamination based on signals received from the group of sensors and the AVC value.