Abstract: Methods and systems are provided for detecting spark plug fouling in an ignition system of an engine. In one example, a method may include directing current flow into a primary winding of an ignition coil of the ignition system for a duration of dwell period responsive to a dwell command from a controller, reducing the current flow to discharge an initial spark, and discharging additional sparks. The method may further include selectively generating an indication of a recommendation to change one or more spark plugs of the ignition system based upon a primary current measured after the dwell period.

Abstract: Methods and systems are provided for purging condensate from a charge air cooler to an engine intake while reducing misfire events related to the water ingestion. During the purging, a spark timing is adjusted based on the amount of condensate purged per cycle. The spark timing is adjusted differently when the condensate is purged during a tip-in versus a pro-active clean-out routine.

Abstract: Methods and systems are provided for inferring spark plug fouling due to accumulation of fuel additives thereon. In one example, an engine controller may infer spark plug fouling due to accumulation of fuel additive based on a combination of engine operating parameters correlated with spark plug health. For example, the engine operating parameters may include a change in an adaptive knock term, an engine pre-ignition rate, and engine exhaust oxygen sensor switching frequency over a vehicle drive cycle, and an engine misfire rate.

Abstract: Methods and systems are provided for determining a type of spark plug fouling. In one example, a method may include differentiating spark plug fouling due to soot accumulation from spark plug fouling due to fuel additive accumulation based on a current on a control wire of the spark plug following application of a dwell command. Further, exhaust oxygen sensor degradation and/or exhaust catalyst degradation may be determined based on switching frequencies of one or more exhaust oxygen sensors and the type of spark plug fouling.

Abstract: Methods and systems are provided for adjusting an ignition energy provided to an engine cylinder upon reactivation from a VDE mode of operation. Ignition energy is increased by increasing an ignition coil dwell time and/or an ignition coil strike frequency. The increased ignition energy improves combustion stability during the transition out of the VDE mode of operation.

Abstract: Methods and systems are provided for purging condensate from a charge air cooler to an engine intake while reducing misfire events related to the water ingestion. During the purging, a spark timing is adjusted based on the amount of condensate purged per cycle. The spark timing is adjusted differently when the condensate is purged during a tip-in versus a pro-active clean-out routine.

Abstract: A method for determining degraded valve operation. According to the method, valve degradation can be determined from the duration of a spark event. This method allows for the determination of both intake and exhaust valve degradation.

Abstract: A method for determining degraded valve operation. According to the method, valve degradation can be determined from the duration of a spark event. This method allows for the determination of both intake and exhaust valve degradation.

Abstract: A method for determining degraded valve operation. According to the method, valve degradation can be determined from the duration of a spark event. This method allows for the determination of both intake and exhaust valve degradation.

Abstract: A method for determining degraded valve operation. According to the method, valve degradation can be determined from the duration of a spark event. This method allows for the determination of both intake and exhaust valve degradation.