An internal combustion engine for a motor vehicle has at least one cylinder for accommodating a piston and at least one pre-chamber spark plug allocated to the combustion chamber of the cylinder. The engine also has a pre-chamber, fluidically connected with the combustion chamber via several openings, in which at least one ignition spark is generable by the pre-chamber spark plug. At the induction stroke of the internal combustion engine, a rinsing of the pre-chamber with inlet gas including at least fuel and air occurs, so that, at the ignition point, an ignitable mixture of fuel and air is accommodated in the pre-chamber.

A control device for an engine is provided, which includes a fuel injector attached to the engine, a spark plug disposed to be oriented into a combustion chamber, a swirl control valve provided in an intake passage, and a controller connected to the fuel injector, the spark plug, and the swirl control valve and configured to control the fuel injector, the spark plug, and the swirl control valve. The swirl control valve closes in a given operating state of the engine. The fuel injector injects fuel after the swirl control valve is closed, between intake stroke and an intermediate stage of compression stroke. The fuel injector injects the fuel after the first fuel injection. The spark plug performs the ignition after the second fuel injection so that the mixture gas starts combustion by flame propagation and then unburned mixture gas self-ignites.

A structure of a combustion chamber for an engine includes a crown surface of a piston, a combustion chamber ceiling surface formed on a cylinder head, an injector and an ignition plug provided on the combustion chamber ceiling surface, and an intake opening and an exhaust opening opened in the combustion chamber ceiling surface. A side where the intake opening is opened is defined as an intake port side, and a side where the exhaust opening is opened is defined as an exhaust port side, with respect to a position, as a reference, where an ignition portion of the ignition plug is disposed in a plan view from one side in a cylinder axis direction, the injector is configured to inject fuel toward the exhaust port side, and a reverse squish flow generation portion, which draws an air-fuel mixture toward the intake port side, is provided in the combustion chamber.

An opposed-piston engine optionally contains an ignition system that is at least partially contained within the combustion chamber to enhance the combustion efficiency of a fuel-air mixture within the combustion system. More specifically, the ignition system contains at least one spark plug having an elongated center electrical delivery electrode, and, an elongated ground electrode. Accordingly, the elongated electrodes extend from an area adjacent to the inner periphery of the cylinder to a radially central area within the combustion chamber. Yet further, a cooling jacket is incorporated to provide cooling of the spark plug.

In an engine (1), when an intake valve (16) opens, a downstream end portion (61) of a first intake port (6) extends to direct to between a shade back (162a) positioned on a cylinder axis (C) side with respect to a valve stem (161) and a ceiling surface (51) facing the shade back (162a). As viewed in a section perpendicular to a direction perpendicular to an intake air flow direction, a second intake port side inner wall surface (61a) at the downstream end portion (61) of the first intake port (6) curves apart from a second intake port (7) in a direction from an exhaust side to an intake side as compared to the shape of an opposite second intake port side inner wall surface (61b) mirror-reversed to a second intake port (7) side.

Various aspects of the present disclosure are directed to a cylinder head for an internal combustion engine. In one example embodiment, the cylinder head includes at least one spark plug having at least one earth electrode, a precombustion chamber accommodating the at least one spark plug, and a fuel channel which leads into the precombustion chamber. The fuel channel having a flow axis at an outlet that is oriented in the direction of the at least one earth electrode. An axis of rotation of the at least one spark plug has an offset with respect to the flow axis between 0 and 15% of the greatest precombustion chamber diameter.

The present disclosure relates to an internal combustion engine, comprising: at least one cylinder; two charge-exchange ports per cylinder, a first charge-exchange port being an inlet port, and a second charge-exchange port being an outlet port; and one spark plug and one prechamber spark plug per each cylinder.

When it is determined that the combustion state during the catalyst warm-up control is unstable, an additional ignition is performed on the TDC side relative to the discharge period CP. In a first countermeasure example, an additional ignition period CP.sub.2 is provided on the TDC side relative to the ignition period CP.sub.1 at the normal time while performing normal ignition and injection. A second countermeasure example is carried out when it is determined that the combustion state is still unstable despite the first countermeasure example. In the second countermeasure example, an additional ignition period CP.sub.3 which is a longer period than the additional ignition period CP.sub.2 is provided instead of the additional ignition period CP.sub.2.

Embodiments of the present invention prevent the occurrence of rapid or intense self-ignition of fuel in an internal combustion engine that performs diesel combustion using a fuel having a relatively high self-ignition temperature. Pre-combustion is brought about by spark ignition during the compression stroke. Thereafter, main injection by an in-cylinder injection valve is performed before the top dead center of the compression stroke. In consequence, combustion of the fuel injected by the main injection is started by flame generated by the pre-combustion, and self-ignition and diffusion combustion of fuel occurs subsequently. Moreover, in at least a part of the operation range of the internal combustion engine, middle injection is performed at a time after the spark ignition of the pre-injected fuel and before the main injection. The fuel injected by the middle injection is burned by propagation of flame.

A thermal insulation film is formed on a bottom surface of a cylinder head facing a top surface of a piston. The thermal insulation film in a region (a circumferential region) of a bottom surface of the cylinder head configuring a squish area in a circumferential edge of a cavity region is formed to be thinner than the thermal insulation film in a region (a cavity region) of the bottom surface of the cylinder head facing a cavity. The thermal insulation film in the circumferential region is polished, and surface roughness thereof is equal to or lower than 3 m. The thermal insulation film in the cavity region is not polished, and surface roughness thereof is 3 to 8 m on average.