An internal combustion engine includes a combustion chamber with a cylinder head, a cylinder, and a piston. The internal combustion engine also includes at least one intake valve and at least one exhaust valve that are connected to the combustion chamber, a fuel injector that injects fuel into the combustion chamber, at least two ignition devices arranged in the combustion chamber, and control means that control the valves, the injector, and the ignition means. The control means operate the engine according to different combustion modes including a controlled ignition combustion mode, a compression ignition combustion mode, and an assisted compression ignition combustion mode. The control means activate the ignition means in the assisted compression ignition combustion mode.

An internal combustion engine includes a combustion chamber with a cylinder head, a cylinder, and a piston. The internal combustion engine also includes at least one intake valve and at least one exhaust valve that are connected to the combustion chamber, a fuel injector that injects fuel into the combustion chamber, at least two ignition devices arranged in the combustion chamber, and control means that control the valves, the injector, and the ignition means. The control means operate the engine according to different combustion modes including a controlled ignition combustion mode, a compression ignition combustion mode, and an assisted compression ignition combustion mode. The control means activate the ignition means in the assisted compression ignition combustion mode.

In an ignition coil for an internal combustion engine, a coil case includes a housing section and a high-voltage tower section. The housing section houses a primary coil, a secondary coil, a center core, and an outer peripheral core, and is arranged outside a plug hole in a cylinder of an internal combustion engine in which an ignition plug is arranged. The high-voltage tower section protrudes from the housing section, and is disposed within the plug hole. A pole joint is disposed within the plug hole, and is mounted to the high-voltage tower section via a seal rubber. The pole joint is provided with a rib that protrudes to an outer periphery and faces an inner peripheral surface of the plug hole. The inner peripheral side of the rib faces the high-voltage tower section via the seal rubber.

In an ignition coil for an internal combustion engine, a coil case includes a housing section and a high-voltage tower section. The housing section houses a primary coil, a secondary coil, a center core, and an outer peripheral core, and is arranged outside a plug hole in a cylinder of an internal combustion engine in which an ignition plug is arranged. The high-voltage tower section protrudes from the housing section, and is disposed within the plug hole. A pole joint is disposed within the plug hole, and is mounted to the high-voltage tower section via a seal rubber. The pole joint is provided with a rib that protrudes to an outer periphery and faces an inner peripheral surface of the plug hole. The inner peripheral side of the rib faces the high-voltage tower section via the seal rubber.

In an ignition coil for an internal combustion engine, a resistor is disposed in a tower insertion hole of a high-voltage tower section. A coil spring is inserted in the tower insertion hole. An inner diameter of a proximal end side portion of the tower insertion hole is larger than an outer diameter of a maximum outer diameter portion of the resistor. An inner diameter of the distal end side portion of the tower insertion hole is larger than an outer diameter of a proximal end side portion of the coil spring, and is smaller than the outer diameter of the maximum outer diameter portion. In a state where the coil spring is pulled out from the tower insertion hole, the maximum outer diameter portion is restrained by the distal end side portion of the tower insertion hole, and a gap is formed between the resistor and a high-voltage cap.

In an ignition coil for an internal combustion engine, a resistor is disposed in a tower insertion hole of a high-voltage tower section. A coil spring is inserted in the tower insertion hole. An inner diameter of a proximal end side portion of the tower insertion hole is larger than an outer diameter of a maximum outer diameter portion of the resistor. An inner diameter of the distal end side portion of the tower insertion hole is larger than an outer diameter of a proximal end side portion of the coil spring, and is smaller than the outer diameter of the maximum outer diameter portion. In a state where the coil spring is pulled out from the tower insertion hole, the maximum outer diameter portion is restrained by the distal end side portion of the tower insertion hole, and a gap is formed between the resistor and a high-voltage cap.

In an internal combustion engine use ignition device includes an ignition coil which has a primary coil and a secondary coil, that are wound around a core, a superimpose circuit which generates an output energy, that is to be superimposed with respect to a secondary current, produced in the secondary coil by the primary coil, a first switch element which is connected to the primary coil and turns on or off of a current to the primary coil, a second switch element which is connected to the superimpose circuit, and stops an operation in a case where the first switch element is turned on, and performs an operation in a case where the first switch element is turned off, and a common input terminal which receives a first driving signal for driving the first switch element and a second driving signal for driving the second switch element.

An internal combustion engine includes a combustion chamber with a cylinder head, a cylinder, and a piston. The internal combustion engine also includes at least one intake valve and at least one exhaust valve that are connected to the combustion chamber, a fuel injector that injects fuel into the combustion chamber, at least two ignition devices arranged in the combustion chamber, and control means that control the valves, the injector, and the ignition means. The control means operate the engine according to different combustion modes including a controlled ignition combustion mode, a compression ignition combustion mode, and an assisted compression ignition combustion mode. The control means activate the ignition means in the assisted compression ignition combustion mode.

In an internal combustion engine use ignition device includes an ignition coil which has a primary coil and a secondary coil, that are wound around a core, a superimpose circuit which generates an output energy, that is to be superimposed with respect to a secondary current, produced in the secondary coil by the primary coil, a first switch element which is connected to the primary coil and turns on or off of a current to the primary coil, a second switch element which is connected to the superimpose circuit, and stops an operation in a case where the first switch element is turned on, and performs an operation in a case where the first switch element is turned off, and a common input terminal which receives a first driving signal for driving the first switch element and a second driving signal for driving the second switch element.

An ignition system for an engine includes a sparkplug, ignition circuitry electrically connected to the sparkplug, and an ignition control unit structured to energize the ignition circuitry to fire the sparkplug at an ignition timing, detect a fault condition caused by an abnormal response of the sparkplug to the energizing, and to energize the ignition circuitry to dry fire the sparkplug at an offset timing such as during an exhaust, stroke based on the detection of the fault condition. Dry firing the sparkplug reduces a break down voltage required to subsequently fire the sparkplug and extends sparkplug service life.