To suppress a failure of ignition of a fuel caused by a spark plug while suppressing wear of an electrode of the spark plug in an internal combustion engine. A control device 1 for an internal combustion engine includes an ignition control unit that controls energization of an ignition coil 300 that applies electric energy to a spark plug 200 that discharges in a cylinder 150 of an internal combustion engine 100 to ignite a fuel. The ignition control unit continuously transmits a first pulse signal (pulse signal for corona discharge) to an igniter connected to the ignition coil 300 before dielectric breakdown between electrodes of the spark plug 200, and continuously transmits a second pulse signal (pulse signal for arc discharge) to the igniter after the dielectric breakdown between the electrodes of the spark plug 200 to control the energization of the ignition coil 300. At this time, a period of the pulse signal for corona discharge is shorter than a period of the pulse signal for arc discharge.

To suppress a failure of ignition of a fuel caused by a spark plug while suppressing wear of an electrode of the spark plug in an internal combustion engine. A control device 1 for an internal combustion engine includes an ignition control unit that controls energization of an ignition coil 300 that applies electric energy to a spark plug 200 that discharges in a cylinder 150 of an internal combustion engine 100 to ignite a fuel. The ignition control unit continuously transmits a first pulse signal (pulse signal for corona discharge) to an igniter connected to the ignition coil 300 before dielectric breakdown between electrodes of the spark plug 200, and continuously transmits a second pulse signal (pulse signal for arc discharge) to the igniter after the dielectric breakdown between the electrodes of the spark plug 200 to control the energization of the ignition coil 300. At this time, a period of the pulse signal for corona discharge is shorter than a period of the pulse signal for arc discharge.

A two-cycle internal combustion engine with rear compression chamber, other than that of a crank case. This present engine has valves that can be screwed on the engine block near top dead center, and is actuated by air pressure. This present two-cycle engine yet uses an oil sump similar to that of a four-cycle engine, which eliminating the need to premix oil with the fuel. This present engine has a stationary piston which operates within a movable piston to form a rear-compression chamber. The movable piston has ports near its crown to transfer charge to the combustion chamber. The movable piston also has ports near bottom of its skirt to allow the fuel and air mixture to enter the rear compression chamber. This engine has a piston seat which is adapted to connect the movable piston to the connecting rod.

A two-cycle internal combustion engine with rear compression chamber, other than that of a crank case. This present engine has valves that can be screwed on the engine block near top dead center, and is actuated by air pressure. This present two-cycle engine yet uses an oil sump similar to that of a four-cycle engine, which eliminating the need to premix oil with the fuel. This present engine has a stationary piston which operates within a movable piston to form a rear-compression chamber. The movable piston has ports near its crown to transfer charge to the combustion chamber. The movable piston also has ports near bottom of its skirt to allow the fuel and air mixture to enter the rear compression chamber. This engine has a piston seat which is adapted to connect the movable piston to the connecting rod.

The objective is to provide an internal-combustion-engine controller that can diagnose, at low cost and in real time, respective combustion states of a subsidiary-chamber-type internal combustion engine. An internal-combustion-engine controller according to the present disclosure controls an internal combustion engine having a main combustion chamber and a subsidiary combustion chamber from which a combustion gas is injected into the main combustion chamber through an orifice provided between the main combustion chamber and the subsidiary combustion chamber to ignite a fuel-air mixture in the main combustion chamber; the internal-combustion-engine controller includes an ion detector that detects an ion in the in the subsidiary combustion chamber and a diagnosis and control device that controls fuel supply to the internal combustion engine and diagnoses a combustion state in the main combustion chamber or in the subsidiary combustion chamber, based on an amount of an ion detected by the ion detector.

The objective is to provide an internal-combustion-engine controller that can diagnose, at low cost and in real time, respective combustion states of a subsidiary-chamber-type internal combustion engine. An internal-combustion-engine controller according to the present disclosure controls an internal combustion engine having a main combustion chamber and a subsidiary combustion chamber from which a combustion gas is injected into the main combustion chamber through an orifice provided between the main combustion chamber and the subsidiary combustion chamber to ignite a fuel-air mixture in the main combustion chamber; the internal-combustion-engine controller includes an ion detector that detects an ion in the in the subsidiary combustion chamber and a diagnosis and control device that controls fuel supply to the internal combustion engine and diagnoses a combustion state in the main combustion chamber or in the subsidiary combustion chamber, based on an amount of an ion detected by the ion detector.

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.

An ignition coil for an internal combustion engine is provided with a primary coil, a secondary coil, a center core, an outer peripheral core, a core cover, a case, and a filling resin. The core cover is formed to cover an inner surface, a surface on one end in the penetration direction, and a surface on the other end in the penetration direction of the outer peripheral core. The core cover has a one end-side cover part, that is, a portion located on a high voltage side of the secondary coil, the cover part facing the surface on one end of the outer peripheral core in the penetration direction, and being formed with a wall portion having an inner surface, an outer surface and a surface on one end in the penetration direction, all of which are formed with a plurality of continuous grooves. The plurality of continuous grooves are filled with the filling resin for filling in the case.

An ignition coil for delivering a spark-generating current to a spark plug includes a magnetically-permeable core; a primary winding disposed outward of the core; and a secondary winding disposed outward of the primary winding and inductively coupled to the primary winding. The secondary winding terminates at one end thereof in a low-voltage end and terminates at another end thereof in a high-voltage end. At least one of the low-voltage end of the secondary winding and the high-voltage end of the secondary winding is electrically connected directly to a terminal through an electrically conductive polymer.

A control apparatus, which is for an internal combustion engine with a spark plug having a center electrode and a ground electrode disposed so as to form a spark discharge gap therebetween, includes a voltage applying section for applying a voltage to the spark discharge gap, a constant-voltage path including a constant-voltage element parallel-connected to the spark discharge gap of the spark plug for preventing the spark discharge gap from being applied with a voltage higher than a set voltage, and an operation control circuit for controlling an operating condition of the internal combustion engine. The operation control circuit is configured to measure a current-flowing time during which a current flows through the constant-voltage path when a voltage higher than the set voltage is applied to the constant-voltage path, and change the operating condition of the internal combustion engine in accordance with the measured current-flowing time.