An ignition apparatus for an internal combustion engine is provided. The ignition apparatus includes an ECU. The ECU calculates a target value E* of an energy input amount of energy inputted into a spark plug based on an in-cylinder flow velocity v, a cylinder pressure P, and an air-fuel ratio AFR. The ECU also calculates a command value I* of a secondary current based on the in-cylinder flow velocity and control an operation of a second circuit according to the target value E* and the command value I*. The calculation of the target value E* using the in-cylinder flow velocity v, the cylinder pressure P, and the air fuel ratio AFR enables the energy input amount to be controlled according to the operating state of the internal combustion engine. The calculation of the command value I* based on the in-cylinder flow velocity v enables the secondary current to be controlled so as to eliminate a risk of the blowout of sparks. The ignition apparatus is, thus, capable of variably changing the amount of energy inputted to the spark plug to improve the fuel consumption.

When an abnormality judgement section judges that there is a failure of an energy inputting circuit, an energy inputting line, through which electrical energy is inputted from the energy inputting circuit to a primary winding, is changed over to a disconnected state by output halt switching means. As a result, since inputting of electrical energy to the primary winding is thereby halted, problems arising due to continuation of inputting electrical energy to the energy inputting circuit can be prevented, even in the event of a failure of the energy inputting circuit, so that reliability can be enhanced.

When an abnormality judgement section judges that there is a failure of an energy inputting circuit, an energy inputting line, through which electrical energy is inputted from the energy inputting circuit to a primary winding, is changed over to a disconnected state by output halt switching means. As a result, since inputting of electrical energy to the primary winding is thereby halted, problems arising due to continuation of inputting electrical energy to the energy inputting circuit can be prevented, even in the event of a failure of the energy inputting circuit, so that reliability can be enhanced.

A method for checking electrodes of a spark gap of an ignition system for a combustion chamber of an internal combustion engine with an externally provided ignition includes generating a spark at the spark gap in an operating state without ignition of an ignitable mixture in the combustion chamber; ascertaining a parameter or characteristic function representing the spark current, the spark voltage, and/or the spark duration; comparing the parameter or the characteristic function to a reference; adapting an energy for a voltage buildup for a further spark generation for the mixture ignition and/or for maintaining an ignition spark for the mixture ignition, in particular for a future ignition process, as a function of a difference between the parameter or the characteristic function and the reference.

An ignition apparatus for an internal combustion engine is provided. The ignition apparatus includes an ECU. The ECU calculates a target value E* of an energy input amount of energy inputted into a spark plug based on an in-cylinder flow velocity v, a cylinder pressure P, and an air-fuel ratio AFR. The ECU also calculates a command value I* of a secondary current based on the in-cylinder flow velocity and control an operation of a second circuit according to the target value E* and the command value I*. The calculation of the target value E* using the in-cylinder flow velocity v, the cylinder pressure P, and the air fuel ratio AFR enables the energy input amount to be controlled according to the operating state of the internal combustion engine. The calculation of the command value I* based on the in-cylinder flow velocity v enables the secondary current to be controlled so as to eliminate a risk of the blowout of sparks. The ignition apparatus is, thus, capable of variably changing the amount of energy inputted to the spark plug to improve the fuel consumption.

An ignition apparatus for an internal combustion engine is provided. The ignition apparatus includes an ECU. The ECU calculates a target value E* of an energy input amount of energy inputted into a spark plug based on an in-cylinder flow velocity v, a cylinder pressure P, and an air-fuel ratio AFR. The ECU also calculates a command value I* of a secondary current based on the in-cylinder flow velocity and control an operation of a second circuit according to the target value E* and the command value I*. The calculation of the target value E* using the in-cylinder flow velocity v, the cylinder pressure P, and the air fuel ratio AFR enables the energy input amount to be controlled according to the operating state of the internal combustion engine. The calculation of the command value I* based on the in-cylinder flow velocity v enables the secondary current to be controlled so as to eliminate a risk of the blowout of sparks. The ignition apparatus is, thus, capable of variably changing the amount of energy inputted to the spark plug to improve the fuel consumption.

A method of firing a spark plug of an internal combustion engine includes supplying AC power to the spark plug in which the AC power has a waveform with a rising edge and a falling edge, activating the spark plug during the rising edge of the waveform, and deactivating the spark plug during the falling edge of the waveform. This method further includes connecting an engine control module to an ignition coil and connecting the engine coil to the spark plug. The firing of the ignition coil mirrors the square waveform of AC power from the engine control module. A battery is connected to the engine control module.

A method of firing at least one spark plug of an internal combustion engine include supplying AC power to the spark plug in which the AC power has a waveform with a rising edge and a falling edge, activating the spark plug during the rising edge of the waveform, and deactivating the spark plug during the falling edge of the waveform. This method further includes connecting an engine control module and a vehicle power supply to at least one AC ignition coil and connecting the AC ignition coil to the spark plug or spark plugs. The firing duration of the AC ignition coil or transformer mirrors a digital square waveform duration from the engine control module.

A method of firing at least one spark plug of an internal combustion engine include supplying AC power to the spark plug in which the AC power has a waveform with a rising edge and a falling edge, activating the spark plug during the rising edge of the waveform, and deactivating the spark plug during the falling edge of the waveform. This method further includes connecting an engine control module and a vehicle power supply to at least one AC ignition coil and connecting the AC ignition coil to the spark plug or spark plugs. The firing duration of the AC ignition coil or transformer mirrors a digital square waveform duration from the engine control module.

A method of firing a spark plug of an internal combustion engine includes supplying AC power to the spark plug in which the AC power has a waveform with a rising edge and a falling edge, activating the spark plug during the rising edge of the waveform, and deactivating the spark plug during the falling edge of the waveform. This method further includes connecting an engine control module to an ignition coil and connecting the engine coil to the spark plug. The firing of the ignition coil mirrors the square waveform of AC power from the engine control module. A battery is connected to the engine control module.