An intake stroke injection and a compression stroke injection are performed during catalyst warm-up control (upper section in FIG. 7). During the catalyst warm-up control, a discharge period at an electrode portion is set on a retard side of compression top dead center, and an expansion stroke injection is performed during the discharge period. However, when a distance between a spray contour surface and the electrode portion increases, an additional injection (first injection) is performed in advance of the expansion stroke injection (second injection) (lower section in FIG. 7). The additional injection is performed at a timing that is on the retard side of compression top dead center and is on an advance side relative to a start timing of the discharge at the electrode portion.

A control device is configured to perform, when it is estimated that a combustion fluctuation increases, estimation related to an ignition delay for initial flame generated from a discharge spark and an air-fuel mixture containing fuel spray injected by intake stroke injection. When it is estimated that the ignition delay for the initial flame is increased from that before the increase in the combustion fluctuation, an injection amount in expansion stroke injection is reduced in a next time cycle. When it is estimated that the ignition delay for the initial flame is reduced from that before the increase in the combustion fluctuation, the injection amount in expansion stroke injection is increased in a next time cycle.

A two-stroke cycle uniflow-scavenged opposed-piston engine is configured to use hydrogen fuel. The opposed-piston engine has at least one cylinder and a pair of pistons disposed for opposed motion in a bore of the cylinder. Hydrogen fuel is injected into the cylinder early in a compression stroke of the opposed-piston engine, and is ignited in a combustion chamber formed between the pistons late in the compression stroke.

An engine ignition timing control method includes: acquiring, by an engine control unit (ECU), intake air humidity of an engine using a humidity sensor; calculating, by the ECU, an amount of first ignition timing correction based on the intake air humidity and an EGR rate; calculating, by the ECU, an amount of second ignition timing correction based on an engine operation region; and correcting, by the ECU, ignition timing of the engine using the amount of first ignition timing correction and the amount of second ignition timing correction.

An engine ignition timing control method includes: acquiring, by an engine control unit (ECU), intake air humidity of an engine using a humidity sensor; calculating, by the ECU, an amount of first ignition timing correction based on the intake air humidity and an EGR rate; calculating, by the ECU, an amount of second ignition timing correction based on an engine operation region; and correcting, by the ECU, ignition timing of the engine using the amount of first ignition timing correction and the amount of second ignition timing correction.

A normal control unit performs a normal control to cause an injection apparatus to perform predetermined normal injection and subsequently cause an ignition plug to perform ignition. In a delay region in a combustion chamber, propagation of flame is retarded further than in another region when the normal control is performed. In a knock state, self-ignition occurs in the delay region when the normal control is performed. When the knock state is established, an adjustment control unit performs, to suppress the self-ignition, an adjustment control to perform main injection and subsequently perform sub-injection in a second half of a compression stroke to adjust a fuel distribution in the combustion chamber to facilitate propagation of flame to the delay region further than in the normal control and subsequently cause the ignition plug to perform the ignition.

The objective is to improve driving feeling at a time of acceleration operation or deceleration operation, by recognizing driver's intention of acceleration or deceleration during straight-ahead running. A driving-assistance control apparatus according to the present disclosure includes a straight-running determination unit that determines whether or not a vehicle is running straight, a head-position detection unit that detects a head position of a driver, a driving-posture determination unit that determines the posture of the driver, based on the head position detected by the head-position detection unit, and a driving-assistance control unit that performs acceleration preparation control for raising a reaction speed for acceleration operation or deceleration preparation control for raising a reaction speed for deceleration operation in accordance with an output of the driving-posture determination unit, when the straight-running determination unit determines that a vehicle is running straight.

An object is to improve scavenging performance of a pre-combustion chamber connected to a main combustion chamber via an orifice and suppress reduction in combustion performance of an internal combustion engine. This control device for an internal combustion engine including a main combustion chamber and a pre-combustion chamber having at least one orifice between the pre-combustion chamber and the main combustion chamber, includes a first control device which controls operation of an ignition coil to generate spark discharge at a spark plug, thus combusting fuel gas, and a second control device which controls operation of the ignition coil at a timing other than the timing of combusting the fuel gas, to promote scavenging of the pre-combustion chamber.

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 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.