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.

An internal combustion engine includes two intake openings, opened and closed by intake valves; exhaust openings opened and closed by exhaust valves; a fuel injector having a plurality of nozzle holes; and mask parts having wall surfaces extending along outer edges of the intake openings toward the inside of the combustion chamber. The fuel injector arranged wherein the nozzle holes are positioned at the opposite exhaust opening sides from the intake openings, and the plurality of nozzle holes include a first nozzle hole, injecting in a direction with the smallest angle from a plane perpendicular to the axial direction of the cylinder. The wall surface formed wherein a height in a first nozzle hole ejection region positioned in a range of injection of a fuel spray from the first nozzle hole, when viewed in the axial direction, is lower than a height in the first nozzle hole ejection region.

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 combustion control device for a compression autoignition engine includes an engine, a state quantity setting device, a spark plug, a controller, and a sensor. The spark plug receives a control signal from the controller and ignites air-fuel mixture at predetermined ignition timing such that the ignited air-fuel mixture is combusted by flame propagation and then unburned air-fuel mixture in a combustion chamber is combusted by autoignition. The controller outputs a control signal to an injector such that, in a compression stroke, fuel is injected at specific timing at which a line obtained by extending an axis of each hole of the injector overlaps with a specific portion including an opening edge of a cavity in an upper surface of a piston.

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 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.

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.

When it is determined that the igniting environment is out of the desired range, the variable valve mechanism is controlled so that the swirl ratio is increased. When the swirl ratio becomes high, the discharge spark and the initial flame move largely in the flow direction of the swirl flow SW and approach the closest fuel spray. Therefore, the discharge spark and the initial flame are attracted to the closest fuel spray and the initial flame enlarges by involving the closest fuel spray (middle stage of FIG. 7). Further, the initial flame enlarges further by involving surrounded fuel spray (lower stage of FIG. 7).

An internal combustion engine includes two intake openings, opened and closed by intake valves; exhaust openings opened and closed by exhaust valves; a fuel injector having a plurality of nozzle holes; and mask parts having wall surfaces extending along outer edges of the intake openings toward the inside of the combustion chamber. The fuel injector arranged wherein the nozzle holes are positioned at the opposite exhaust opening sides from the intake openings, and the plurality of nozzle holes include a first nozzle hole, injecting in a direction with the smallest angle from a plane perpendicular to the axial direction of the cylinder. The wall surface formed wherein a height in a first nozzle hole ejection region positioned in a range of injection of a fuel spray from the first nozzle hole, when viewed in the axial direction, is lower than a height in the first nozzle hole ejection region.