In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug, the intake-side inclined surface and the exhaust-side inclined surface are formed in such a way that an inclination angle of the exhaust-side inclined surface is smaller than an inclination angle of the intake-side inclined surface, and a difference in inclination angle between the intake-side inclined surface and the exhaust-side inclined surface is 4 degrees or larger.

In a piston of an internal combustion engine in which a recessed portion that holds an intake air swirling flow is formed on a crown surface of the piston, the crown surface includes a heat insulating film formation portion having a heat insulating film whose thermal conductivity is lower than a base material of the piston, the heat insulating film whose thermal capacity per volume is smaller than the base material of the piston, and a heat insulating film non-formation portion provided at a position on the more outside of a cylinder bore side of the internal combustion engine than the heat insulating film formation portion, the heat insulating film non-formation portion not having the heat insulating film.

Provided is an in-combustion chamber flow control device used in an engine having an intake passage connected to an intake opening formed in a ceiling surface of a combustion chamber, at an angle inclined with respect to a direction of an axis of a cylinder. This in-combustion chamber flow control device comprises a plasma actuator (28) disposed inside the combustion chamber (16). The plasma actuator comprises: a dielectric body (38) disposed along the ceiling surface (16a) of the combustion chamber, at a position closer to a center of the ceiling surface than the intake opening (18a); an exposed electrode (40) disposed on one side of the dielectric body facing the combustion chamber; and an embedded electrode (42) disposed on a side opposite to the exposed electrode across the dielectric body. The embedded electrode is disposed at a position closer to the intake opening than the exposed electrode.

The invention relates to an internal combustion engine and to a method for operating the internal combustion engine, which has at least one cylinder having a combustion chamber, the combustion chamber being bounded by a cylinder roof, a cylinder wall and a movable cylinder piston, a multi-hole injection nozzle and a spark plug being arranged in a central position in the cylinder roof, the multi-hole injection nozzle injecting fuel into the combustion chamber at injection pressures of >/=300 bar by means of a plurality of injection jets. It is provided that at least one injection jet (i>/=1) injects fuel into a three-dimensional space within the combustion chamber on the intake side, which space lies below an opening of at least one intake valve (104A, 104B) with respect to the direction of the longitudinal central axis (Z) of the cylinder, and at least four injections jets (i>/=4) inject fuel into a three-dimensional space of the combustion chamber on the exhaust side, which space lies below an opening of at least one exhaust valve (105A, 105B).

Examples are directed to a fuel injection device positioned in a cylinder liner. In one example, a cylinder includes a combustion chamber which is jointly formed by a piston crown of a piston, by a cylinder barrel which laterally delimits the combustion chamber, and by a cylinder head. The cylinder includes an injection device positioned in the cylinder barrel for direct introduction of fuel into the combustion chamber, which injection device has at least one opening which, during a course of an injection process, is configured to be activated to introduce fuel into the combustion chamber, the injection device terminating flush, at a combustion chamber side, with the cylinder barrel.

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug, the intake-side inclined surface and the exhaust-side inclined surface are formed in such a way that a ratio of a length of the exhaust-side inclined surface with respect to a length of the intake-side inclined surface is 1.25 or larger in a cross section passing through a center axis of the piston and orthogonal to an axis direction of a crankshaft.

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug. The cavity includes a bottom surface and a tubular peripheral surface, and is formed in such a way that a ratio of a depth of the cavity with respect to a diameter of the cavity is 0.3 or smaller.

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug, the intake-side inclined surface and the exhaust-side inclined surface are formed in such a way that an angle defined by an orthogonal plane orthogonal to a center axis of a cylinder and the exhaust-side inclined surface) is smaller than an angle defined by the orthogonal plane and a valve head bottom surface of an exhaust valve, and an inclination angle difference between the exhaust-side inclined surface and the valve head bottom surface of the exhaust valve is larger than an inclination angle difference between the intake-side inclined surface and a valve head bottom surface of an intake valve by 3 degrees or larger.

The center injection engine is an engine equipped with the direct injector and an ignition apparatus at center of a ceiling part of the combustion chamber. The positive tumble flow flows from the intake port side to the exhaust port side on the ceiling part side of the combustion chamber, and also flows from the exhaust port side to the intake port side on the piston top part side. The ECU calculates the injection timing of the direct injector based on the engine load. In the first injection control, the higher the engine load becomes, the more the end crank angle is retarded.

A control device of an engine including a cylinder, a piston, a cylinder head, and a combustion chamber, is provided. The device includes intake and exhaust ports, a swirl control valve, a fuel injection valve attached to the cylinder head to be oriented into the combustion chamber and having first and second nozzle ports, and a control unit. The control unit includes a processor configured to execute a swirl opening controlling module to control the swirl control valve to have a given opening at which a swirl ratio inside the combustion chamber becomes 2 or above, and a fuel injection timing controlling module to control the fuel injection valve to inject fuel at a given timing at which the swirl ratio becomes 2 or above and a swirl flow from a lower portion to a higher portion of the combustion chamber in a side view occurs.