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 between the lower cavity and the upper cavity. 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 outputs a control signal to a fuel injection valve so that a distribution ratio for the upper cavity is higher when the engine operates in the second state than when in the first state.

A piston includes a piston body having an outer cylindrical surface and defined along a longitudinal piston center axis. The piston further includes a piston bowl with a half section profile with a bowl entry extending radially from the longitudinal piston center axis; a bowl recess extending radially from the bowl entry; and a soot shelf extending from the bowl recess to define a soot shelf axial height (H) and a soot shelf radial width (W). The soot shelf includes an inner step being formed by an inner step base surface extending radially from the bowl recess; an outer step being formed by a step shoulder surface extending axially from the inner step base surface and an outer step base surface extending radially from the step shoulder surface; and a soot shelf shoulder surface extending axially from outer step base surface to the end perimeter surface.

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.

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 compression-ignition engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. 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 speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller increases an injection amount per pilot injection when the engine operates in the second state than when the engine operates in the first state.

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 between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when an engine operates in a first state and a second state in which the speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller maintains an injection amount of the main injection and increases an injection amount of the pilot injection(s) when the engine operates in the second state as compared to when the engine operates in the first state.

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 between the lower cavity and the upper cavity. 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 outputs a control signal to a fuel injection valve so that a distribution ratio for the upper cavity is higher when the engine operates in the second state than when in the first state.

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 compression-ignition engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. 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 higher than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller causes a ratio of injection amount per pilot injection to the total injection amount to be higher when the engine operates in the second state than when the engine operates in the first state.

A cavity provided at a crown surface of a piston includes a first cavity section provided in a central area in a radial direction, a second cavity section provided outside the first cavity section, and a lip provided to connect the first-and-second cavity sections. Plural injection holes of an injector include a first injection-hole group where plural first injection holes directed toward a part close to the piston in a cylinder-axis direction are provided in a ring shape and a second injection-hole group where plural second injection holes directed toward a part close to a ceiling surface of a combustion chamber in the cylinder-axis direction are provided in the ring shape. The first injection-hole group and the second injection-hole group are positioned so as to inject fuel toward the lip concurrently.

Apparatuses, systems and method for utilizing multi-zoned combustion chambers (and/or multiple combustion chambers) for achieving compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in an internal combustion engine are provided. In addition, improved apparatuses, systems and methods for achieving and/or controlling compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in a Siamese cylinder internal combustion engine are provided.

A control device for an engine is provided. A cavity formed in a crown surface of a piston of the engine includes a first cavity part disposed in a radially center area, a second cavity part disposed radially outward of the first cavity part, and a connecting part connecting these two parts. The control device causes a fuel injection valve to perform a first injection in which fuel is injected at a timing when the piston is located at an advancing side of CTDC and an injection axis thereof intersects with the connecting part, a second injection in which fuel is injected toward the first cavity part at a retarding side of the first injection, and a middle injection in which fuel is injected at a timing between the first and second injections, for a period shorter than each of the first and second injections.