An apparatus for igniting a fuel mixture provides an ignition system for generating a high-voltage ignition voltage, a circuit device comprising a circuit for superimposing a high-frequency signal on to the high-voltage ignition voltage, a spark plug in an engine block, and a transmission element having a high-voltage conductor which is guided in an insulation element. The high-voltage conductor is used for transmitting the ignition voltage, onto which the high-frequency signal has been superimposed, to the spark plug. Further provided is an electrically conducting shielding element which surrounds the high-voltage conductor in an electromagnetically shielding manner at least along one portion of the longitudinal axis of the high-voltage conductor. The shielding element is connected in an electrically conducting manner to a ground potential of the circuit device and establishes a connection between the ground potential of the circuit device and a ground electrode of the spark plug.

An internal-combustion-engine control apparatus according to the present disclosure controls an internal combustion engine having a main combustion chamber, a subsidiary combustion chamber, an ignition plug that is disposed in the subsidiary combustion chamber, an ignition coil connected with the ignition plug, and an orifice for connecting the subsidiary combustion chamber with the main combustion chamber and for injecting combustion gas in the subsidiary combustion chamber into the main combustion chamber; the internal-combustion-engine ignition apparatus includes an ignition control unit that controls energization of the ignition coil so that an ignition discharge for igniting a fuel-air mixture in the subsidiary combustion chamber is produced across the ignition plug, and a pressure-boosting control unit that controls energization of the ignition coil so that a pressure-boosting discharge for increasing a pressure of combustion gas in the subsidiary combustion chamber is produced across the ignition plug.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector and the main spark plug and the subspark plug. In a low-load range where an engine load is below a given reference load, the controller controls the main spark plug and the subspark plug so that the subignition is performed after performing the main ignition, and the controller retards the timing of the subignition in a high-speed range where an engine speed is above a given reference engine speed, compared with a low-speed range below the reference engine speed.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector, the main spark plug and the subspark plug. When an engine load is above a given reference load, the controller controls, in a low-speed range below a given reference engine speed, the ignition devices so that the subignition is performed after the main ignition, and the controller controls, in a high-speed range exceeding the reference engine speed, the ignition devices so that only the subignition is performed, or so that the main ignition is performed at the same timing as or after the subignition.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector, the main spark plug and the subspark plug. When an engine speed is above a given reference engine speed, the controller controls, in a low-load range below a given reference load, the ignition devices so that the subignition is performed after the main ignition, and the controller controls, in a high-load range exceeding the reference load, the ignition devices so that only the subignition is performed, or so that the main ignition is performed at the same timing as or after the subignition.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a control device. In a low-speed high-load range, a fuel injection timing is set in compression stroke and the main ignition and the subignition are performed after the fuel injection timing, and the fuel injection timing under a low-speed condition becomes later than that under a high-speed condition, and the ignition devices are controlled so that the subignition timing is retarded from the main ignition timing and an ignition phase difference that is the retard amount of the subignition timing becomes larger under the low-speed condition than under the high-speed condition.

An engine system is provided, which includes a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, an exhaust gas recirculation (EGR) device and a control device. In a specific range where EGR is performed, the ignition devices are controlled so that a subignition timing is retarded from a main ignition timing, and an ignition phase difference that is a retard amount of the subignition timing from the main ignition timing becomes larger under a high EGR condition than a low EGR condition, the EGR conditions being conditions in the specific range where engine speeds are the same and EGR rates are different, and the high EGR condition being larger in the EGR rate than the low EGR condition.

An engine system is provided, which includes a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, and a subspark plug that ignites the mixture gas inside the subchamber, an throttle valve, and a control device. In a first range, compression self-ignition combustion of the mixture gas inside the main combustion chamber is performed. In a second range, flame propagation combustion is performed while setting an air-fuel ratio of the mixture gas lower than that in the first range. Immediately after the transition from the first range to the second range, only the subignition is performed, or the subignition and the main ignition are performed while setting a timing of the main ignition to a timing same as or retarded from the subignition.

An ignition coil control system includes: a plurality of ignition coils that respectively include a primary coil and a secondary coil; a spark plug that generates a spark discharge by a discharge current generated by the plurality of ignition coils and that includes a center electrode and a ground electrode; a sensing part measuring a current applied to the primary coil; and an ignition controller that adjusts a reference duty signal based on an amount of the current applied to the primary coil sensed by the sensing part to adjust discharge energy generated between the center electrode and the ground electrode through the secondary coil.

The objective is to obtain an internal-combustion-engine ignition apparatus that raises the ignitability at a time when a smolder occurs. An internal-combustion-engine ignition apparatus having a main combustion chamber and a subsidiary combustion chamber includes an ignition plug, an ignition coil having a primary coil, a secondary coil, and a tertiary coil, a first switching circuit that turns on or off energization of the primary coil, a second switching circuit that turns on or off energization of the tertiary coil, and a control apparatus that estimates a combustion state, that performs on/off-control of the first switching circuit so that a spark discharge is produced in the ignition plug and that performs on/off-control of the second switching circuit so that magnetic flux in the tertiary coil is changed so as to increase a secondary current, when deterioration of a combustion state has been estimated.