A metering system for a fluid atomizer includes a housing, first and second metering members, and at least one solenoid. The housing includes a mixing chamber. The first metering member is operable to control flow of a first fluid to the mixing chamber. The second metering member is arranged coaxial with the first metering member and operable to control flow of a second fluid to the mixing chamber. The at least one solenoid is configured to operate at least one of the first and second metering members.

An internal combustion engine comprises a fuel injector 31, a spark plug 16, a piston 14 having a cavity 91, a swirl control device 95, and a control system 70. The cavity is formed so as to change in distance from the fuel injector to a side wall surface of the cavity, in the circumferential direction. The system performs ignition assist control for successively performing injections of main fuel and ignition assist fuel, makes an air-fuel mixture formed by the ignition assist fuel burn by flame propagation by the spark plug, and makes the remaining fuel burn by pre-mix compression self-ignition. The system controls the swirl control device during the ignition assist control so that when the engine load is high, the fuel sprayed heads toward parts of the side wall surface which are short in distances from the fuel injector.

An internal combustion engine comprises a fuel injector 31, a spark plug 16, a piston 14 having a cavity 91, a swirl control device 95, and a control system 70. The cavity is formed so as to change in distance from the fuel injector to a side wall surface of the cavity, in the circumferential direction. The system performs ignition assist control for successively performing injections of main fuel and ignition assist fuel, makes an air-fuel mixture formed by the ignition assist fuel burn by flame propagation by the spark plug, and makes the remaining fuel burn by pre-mix compression self-ignition. The system controls the swirl control device during the ignition assist control so that when the engine load is high, the fuel sprayed heads toward parts of the side wall surface which are short in distances from the fuel injector.

A spark-ignition direct fuel injection valve includes, at least, a seat member provided with a fuel injection hole and a valve seat and a valve body which controls fuel injection from the injection hole by contacting and separating from the valve seat. In the spark-ignition direct fuel injection valve: the injection hole has an injection hole inlet which is open inwardly of the seat member and an injection hole outlet which is open outwardly of the seat member; an opening edge of the injection hole inlet has a first round-chamfered portion formed on an upstream side with respect to a fuel flow toward the injection hole inlet; and an extending length (L) of the injection hole does not exceed three times a hole diameter (D) of the injection hole.

A metering system for a fluid atomizer includes a housing, first and second metering members, and at least one solenoid. The housing includes a mixing chamber. The first metering member is operable to control flow of a first fluid to the mixing chamber. The second metering member is arranged coaxial with the first metering member and operable to control flow of a second fluid to the mixing chamber. The at least one solenoid is configured to operate at least one of the first and second metering members.

A metering system for a fluid atomizer includes a housing, first and second metering members, and at least one solenoid. The housing includes a mixing chamber. The first metering member is operable to control flow of a first fluid to the mixing chamber. The second metering member is arranged coaxial with the first metering member and operable to control flow of a second fluid to the mixing chamber. The at least one solenoid is configured to operate at least one of the first and second metering members.

A spark-ignition direct fuel injection valve includes, at least, a seat member provided with a fuel injection hole and a valve seat and a valve body which controls fuel injection from the injection hole by contacting and separating from the valve seat. In the spark-ignition direct fuel injection valve: the injection hole has an injection hole inlet which is open inwardly of the seat member and an injection hole outlet which is open outwardly of the seat member; an opening edge of the injection hole inlet has a first round-chamfered portion formed on an upstream side with respect to a fuel flow toward the injection hole inlet; and an extending length (L) of the injection hole does not exceed three times a hole diameter (D) of the injection hole.

A spark-ignition direct fuel injection valve includes, at least, a seat member provided with a fuel injection hole and a valve seat and a valve body which controls fuel injection from the injection hole by contacting and separating from the valve seat. In the spark-ignition direct fuel injection valve: the injection hole has an injection hole inlet which is open inwardly of the seat member and an injection hole outlet which is open outwardly of the seat member; an opening edge of the injection hole inlet has a first round-chamfered portion formed on an upstream side with respect to a fuel flow toward the injection hole inlet; and an extending length (L) of the injection hole does not exceed three times a hole diameter (D) of the injection hole.

A spark-ignition direct fuel injection valve includes, at least, a seat member provided with a fuel injection hole and a valve seat and a valve body which controls fuel injection from the injection hole by contacting and separating from the valve seat. In the spark-ignition direct fuel injection valve: the injection hole has an injection hole inlet which is open inwardly of the seat member and an injection hole outlet which is open outwardly of the seat member; an opening edge of the injection hole inlet has a first round-chamfered portion formed on an upstream side with respect to a fuel flow toward the injection hole inlet; and an extending length (L) of the injection hole does not exceed three times a hole diameter (D) of the injection hole.

A fuel injector configured as a high-pressure injection valve for the direct injection of fuel into a combustion chamber includes: a housing having an housing end face on the combustion chamber side; an actuator; a valve-closure member operable by the actuator; at least one outlet orifice in the housing end face on the combustion chamber side for the fuel, the valve-closure member selectively closing or opening the outlet orifice; and a ring provided round about the outlet orifice in the housing end face on the combustion chamber side.