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.

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.

An internal combustion engine control apparatus includes: an ignition coil including a primary coil and a secondary coil that are magnetically coupled to each other; a first switch element for turning on and off a current to the primary coil; and a spark plug, for igniting an air-fuel mixture in an internal combustion engine by using a spark discharge caused by switching the first switch element from the ON state to the OFF state. The internal combustion engine control apparatus is configured to: determine occurrence of one of an abnormality in a discharge voltage and a misfire of the spark plug, when the calculated time duration in which a voltage of the primary coil after the switching of the first switch element from the ON state to the OFF state is above a predetermined comparison reference voltage does not fall within an allowable range.

An internal combustion engine control apparatus includes: an ignition coil including a primary coil and a secondary coil that are magnetically coupled to each other; a first switch element for turning on and off a current to the primary coil; and a spark plug, for igniting an air-fuel mixture in an internal combustion engine by using a spark discharge caused by switching the first switch element from the ON state to the OFF state. The internal combustion engine control apparatus is configured to: determine occurrence of one of an abnormality in a discharge voltage and a misfire of the spark plug, when the calculated time duration in which a voltage of the primary coil after the switching of the first switch element from the ON state to the OFF state is above a predetermined comparison reference voltage does not fall within an allowable range.

The present disclosure refers to a method for detecting an exchange of a component of an ignition system of a spark-ignited internal combustion engine. The method comprises the step of determining at least one parameter being indicative of an operation or condition of the ignition system; and the step of detecting an exchange of the component based on a comparison of the parameter with at least one reference value.

The present disclosure refers to a method for detecting an exchange of a component of an ignition system of a spark-ignited internal combustion engine. The method comprises the step of determining at least one parameter being indicative of an operation or condition of the ignition system; and the step of detecting an exchange of the component based on a comparison of the parameter with at least one reference value.

The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

An ignition system for an internal combustion engine includes an ignition coil forming a part of a primary circuit and a secondary circuit, a power source to supply power to the ignition coil, and a controller to determine whether the ignition coil is a recognized ignition coil based on a measured risetime and a measured current level in the primary circuit, the measured current level being lower than that required to create a breakdown voltage of the ignition coil.

An ignition system for an internal combustion engine includes an ignition coil forming a part of a primary circuit and a secondary circuit, a power source to supply power to the ignition coil, and a controller to determine whether the ignition coil is a recognized ignition coil based on a measured risetime and a measured current level in the primary circuit, the measured current level being lower than that required to create a breakdown voltage of the ignition coil.