A piston of an internal combustion engine configured to be reciprocable along an axial direction in a cylinder includes a cavity formed to be recessed in a center of a piston top surface, and an outer circumferential edge portion located on a radially outer side of the cavity in the piston top surface. The cavity includes a lip portion, a raised portion, and a curved portion. The curved portion includes an outer circumference-side curved surface which includes a curved surface connected to the lip portion, an inner circumference-side concave surface which is located on a radially inner side of an outer circumference-side curved surface and includes a surface connected to a raised portion, the inner circumference-side concave surface including a deepest portion of the cavity, and a convex surface formed between the outer circumference-side curved surface and the inner circumference-side concave surface, as well as protruding upward.

This piston for a diesel engine includes: a bottom portion that has a deepest combustion chamber bottom in the combustion chamber; a circumferential protrusion that is provided around an entire circumference of a circumferential wall between the bottom portion and a top surface of the piston and protrudes toward an intersection (P0) of a center line of the piston and the top surface in a cross-sectional view that includes the center line; an inclination portion that inclines closer to the top surface toward an outer side in a radial direction from the circumferential protrusion; and a rising portion that rises from the inclination portion toward the top surface.

A piston of an internal combustion engine configured to be reciprocable along an axial direction in a cylinder includes a cavity formed to be recessed in a center of a piston top surface, and an outer circumferential edge portion located on a radially outer side of the cavity in the piston top surface. The cavity includes a lip portion which has an inclined surface extending obliquely downward from the outer circumferential edge portion toward a radially inner side, a raised portion protruding upward from a bottom of the cavity, and a curved portion connecting the raised portion and the lip portion. The curved portion includes an outer circumference-side curved surface which includes a curved surface connected to the lip portion, an inner circumference-side concave surface which is located on the radially inner side of the outer circumference-side curved surface and includes a surface connected to the raised portion, the inner circumference-side concave surface including a deepest portion of the cavity, and a convex surface formed between the outer circumference-side curved surface and the inner circumference-side concave surface, as well as protruding upward.

The present disclosure relates to a piston for an internal combustion engine. The piston comprises a cover which at least partially covers a piston basehead of the piston. A heat-isolating air gap is formed between the cover and the piston basehead, which is fluidically connected to a combustion chamber and/or an upper side of the cover facing away from the heat-isolating air gap. The fluidic connection permits a fluid exchange to take place between the heat-isolating air gap and the combustion chamber. In this way, a pressure gradient can be reduced between the combustion chamber and the heat-isolating air gap. As a result, the cover is/can be kept thin without being deformed during combustion.

The present invention discloses an apparatus for optimizing the fuel/air mixing process of an internal combustion engine. The bottom surface of the cylinder head is provided with a plurality of brackets; a ring is fixed to the brackets; and the ring may be an integrated ring body and may also be composed of a plurality of small segments. The ring is positioned opposite to a fuel injector and located in an area where fuel flows in the the combustion chamber. The ring can continuously guides the fuelduring the fuel injection process. The ring can be arranged in the liquid-phase region, the gas-liquid two-phase region or the gas-phase region. When the location of the ring interferes with the movement of valves of the internal combustion engine, the part of the ring body that interferes with the movement of the valves can be removed.

The piston has a contoured combustion bowl with a radially inner shelf portion that is spaced axially away from the radially outer lip portion a first axial distance, and a swirl pocket that extends radially from the radially inner shelf portion and defines a lower axial extremity that is spaced axially away from the radially outer lip portion a second axial distance that is greater than the first axial distance. The swirl pocket defines a tangent extending in the radially outer direction, forming an acute angle with the radially outer lip portion ranging from 70 degrees to 80 degrees.

A piston for use in a GDCI engine cooperates with the wall of a cylinder defined in the engine and with a cylinder head to define a combustion chamber. The surface of the piston that faces the cylinder head defines a bowl that is configured to receive fuel that is dispensed from a fuel injector that is located in the cylinder head substantially along the central axis of the cylinder. The bowl is configured such that substantially all of the injected fuel associated with a combustion event reaches a localized equivalence ratio greater than 0.0 and less than or equal to 1.2 at a time immediately preceding initiation of the combustion event.

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 piston for an internal combustion engine includes a piston body having a generally planar crown and a sidewall extending from the crown. A stepped combustion bowl is recessed in the crown and includes an outer bowl recessed relative to the crown and defining a generally planar annular floor surface. The stepped combustion bowl further includes an inner bowl recessed relative to the outer bowl. The inner bowl includes a sidewall that slopes continually inwardly from the outer bowl to a floor surface of the inner bowl. A plurality of protruding lips extend from the sidewall toward a central axis of the piston body.

A piston for an internal combustion engine includes a plurality of valve pockets formed in a piston rim, the valve pockets forming fluid flow paths through the piston rim. Each of the valve pockets includes a central step standing proud of a pocket floor to limit a fluid flow area through the pocket and slow combustion gas flow from a combustion bowl toward a cylinder liner and thereby reduce displacement of an engine oil film thereon.