An engine ignition system for a spark-ignited engine includes a sparkplug and a control system having primary ignition circuitry, secondary ignition circuitry coupled with electrodes of the sparkplug, and sensing circuitry. A control device determines a timing of spark production based on a pattern of varying of an electrical property in the primary ignition circuitry. An inflection point in a sensed current signal may be detected to determine the timing.

An engine ignition system for a spark-ignited engine includes a sparkplug and a control system having primary ignition circuitry, secondary ignition circuitry coupled with electrodes of the sparkplug, and sensing circuitry. A control device determines a timing of spark production based on a pattern of varying of an electrical property in the primary ignition circuitry. An inflection point in a sensed current signal may be detected to determine the timing.

A method for operating an internal combustion engine includes operating at least one cylinder pre-chamber in a homogeneous charge compression ignition (HCCI) combustion mode by providing an air/fuel mixture in the pre-chamber that is fluidly connected to the at least one engine cylinder, creating H and OH radicals in the pre-chamber to achieve an ignition in the at least one pre-chamber, determining whether an ignition timing is advanced or delayed relative to a desired timing, and delaying the ignition when the ignition is advanced relative to the desired timing by cooling the pre-chamber and the at least one engine cylinder.

A method for operating an internal combustion engine includes operating at least one cylinder pre-chamber in a homogeneous charge compression ignition (HCCI) combustion mode by providing an air/fuel mixture in the pre-chamber that is fluidly connected to the at least one engine cylinder, creating H and OH radicals in the pre-chamber to achieve an ignition in the at least one pre-chamber, determining whether an ignition timing is advanced or delayed relative to a desired timing, and delaying the ignition when the ignition is advanced relative to the desired timing by cooling the pre-chamber and the at least one engine cylinder.

A method for controlling an internal combustion engine. Target ignition times for the individual cylinders are given by an engine control device through trigger signals transmitted to the ignition control device. After receiving a trigger signal, the ignition control device activates the ignition device associated with this trigger signal to effect ignition in the respective cylinder. The ignition control device stores a firing order in which an ignition is to be cyclically effected in the individual cylinders, and it is checked whether trigger signals for all cylinders are received in the stored firing order, and if not, a substitutional ignition time is calculated for the at least one cylinder for which no trigger signal has been received, from at least two trigger signals for the cylinders or one of the remaining cylinders, and the respective ignition device or ignition devices are activated according to the calculated substitutional ignition 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.

Systems and methods for operating a vehicle that includes an engine and an electric machine are described. In one example, operation of the engine may be adjusted to compensate for conditions when carbon deposits may build on one or more engine spark plugs. The engine adjustments may help to remove carbon deposits from the engine's spark plugs.

Systems and methods for operating a vehicle that includes an engine and an electric machine are described. In one example, operation of the engine may be adjusted to compensate for conditions when carbon deposits may build on one or more engine spark plugs. The engine adjustments may help to remove carbon deposits from the engine's spark plugs.

An engine ignition system for a spark-ignited engine includes a sparkplug and a control system having primary ignition circuitry, secondary ignition circuitry coupled with electrodes of the sparkplug, and sensing circuitry. A control device determines a timing of spark production based on a pattern of varying of an electrical property in the primary ignition circuitry. An inflection point in a sensed current signal may be detected to determine the timing.

An engine ignition system for a spark-ignited engine includes a sparkplug and a control system having primary ignition circuitry, secondary ignition circuitry coupled with electrodes of the sparkplug, and sensing circuitry. A control device determines a timing of spark production based on a pattern of varying of an electrical property in the primary ignition circuitry. An inflection point in a sensed current signal may be detected to determine the timing.