In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the engine includes a lower cavity, an upper cavity, and a lip portion therebetween. A controller causes a main injection and at least one pilot injection to be executed when the engine operates in a first state and a second state in which the load is lower than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller sets the timing of the pilot injection(s) so that the distribution ratio of the fuel spray of the pilot injection(s) for the lower cavity is higher when the engine operates in the first state than when in the second state.

A spark ignition internal combustion engine includes: intake and exhaust valves disposed at a ceiling part of a combustion chamber; and a fuel injection valve including a tip end portion including injection holes, and being structured to inject fuel through the injection holes toward a crown of a piston, wherein the tip end portion of the fuel injection valve is arranged in a region of the ceiling part surrounded by the intake and exhaust valves. A fuel injection control includes: determining a tip end portion fuel temperature directly or indirectly, which is a temperature of fuel at the tip end portion of the fuel injection valve; and setting a fuel injection timing advanced, in response to a condition that the tip end portion fuel temperature is higher than a temperature threshold value, wherein the temperature threshold value relates to flash boiling of fuel at the injection holes.

Embodiments disclosed herein relate to internal combustion engines, combustion systems that include such internal combustion engines, and controls for controlling operation of the combustion engine. The internal combustion engine may include one or more mechanisms for injecting fuel, air, fuel-air mixture, or combinations thereof directly into one or more cylinders, and controls may operate or direct operation of such mechanisms.

A gasoline direct injection (GDI) engine may include: a cylinder block having a cylinder; a cylinder head having an intake port, an intake valve opening and closing the intake port, an exhaust port, and an exhaust valve opening and closing the exhaust port; a piston reciprocating in the cylinder; a combustion chamber defined by the cylinder head, the piston, and an inner wall surface of the cylinder; and a fuel injector injecting a fuel into the combustion chamber. In particular, the combustion chamber is divided into an intake side where the intake port and the intake valve are located, and an exhaust side where the exhaust port and the exhaust valve are located, and a nozzle of the fuel injector is mounted in the cylinder head toward the exhaust side.

The internal combustion engine comprising: a catalyst arranged in an exhaust passage and able to store oxygen, a variable valve timing mechanism able to change a valve overlap amount between an intake valve and an exhaust valve, and a fuel supplying means for feeding fuel to the exhaust passage. The fuel supplying means feeds fuel to the exhaust passage only in an initial cycle after scavenging where valve overlap causes air to be expelled from an intake passage through a cylinder to the exhaust passage if such scavenging occurs.

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.

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).

A nozzle hole of a nozzle plate is coupled to a fuel injection port of a fuel injection device via a swirl chamber and first and second fuel guide channels opened into the swirl chamber. The swirl chamber is formed by combining first and second elliptical-shaped recessed portions. The first fuel guide channel opens at a side of a short axis of the first elliptical-shaped recessed portion and a side of the short axis that does not overlap with the second elliptical-shaped recessed portion, and the second fuel guide channel opens at a side of a short axis of the second elliptical-shaped recessed portion and a side of the short axis that does not overlap with the first elliptical-shaped recessed portion. The first and second fuel guide channels have depths deeper than those of the swirl chamber and extend inside of the swirl chamber while gradually reducing cross-sectional areas.

Various systems are provided a piston for an engine. The piston has a piston crown, which includes a plurality of protrusions for enhancing mixing in a combustion chamber. As one example, a piston crown includes a plurality of protrusions extending outward from a top surface of the piston crown and spaced apart from one another around a circumference of the piston crown, each protrusion of the plurality of protrusions increasing in height and decreasing in width as the protrusion extends outward from a central axis of the piston crown.