In an opposed-piston engine, a piston has a top land. The piston top land has a non-cylindrical shape which affords more clearance with a piston bore to thrust and anti-thrust sides than to front-facing and rear facing sides.

A piston for an internal combustion engine is disclosed. The piston comprises a number of fuel directing surfaces for directing a fuel spray sprayed onto the fuel directing surface. At least one of the fuel direction surfaces is/are inclined relative to a tangential direction of the piston. The present disclosure further relates to an engine comprising a piston and a vehicle comprising an internal combustion engine.

The invention relates to an HPDF operation method for an internal combustion engine (100) with internal formation of a mixture and self-ignition, in which, (i) for a combustion cycle of an operation cycle under high pressure, as main fuel (63) at a first time point, the introduction of a nonself-igniting or gasoline engine fuel, and as ignition fuel (64) at a second time point, the introduction of a self-igniting or diesel fuel into a combustion chamber (20) of the internal combustion engine (1) are at least initiated and/or performed, (ii) a self-ignition of the ignition fuel (64) and with the self-ignition a nonself-ignition of the main fuel (63) are effected, and (iii) the self-ignition of the ignition fuel (64) is performed temporally and/or spatially in such a way that the main fuel (63) is ignited at a location (1) and/or in a region of an jet tip (630 and/or a propagation front (630 of a quantity of introduced main fuel (63)—in particular temporally firstly.

An internal combustion engine system includes an engine housing having a combustion cylinder, and a piston movable within the combustion cylinder to increase a pressure therein to an autoignition threshold for injected fuel. The piston includes a piston crown having a combustion face forming a combustion bowl, and varied in profile to form jet-jet interaction limiters at locations offset from fuel spray jet paths from a fuel injector. The jet-jet interaction limiters include a bowl component and a step component protruding, respectively, within the combustion bowl and a step located transitioning between the combustion bowl and a circumferential rim of the piston. Limiting jet-jet interaction limits soot production in exhaust produced by the engine.

A piston for an internal combustion engine is provided. The piston includes a piston bowl defined by a floor surface and a rim wall extending from an outer periphery of the floor surface in a system vertical direction to circumferential surround the floor surface. The piston bowl includes a center portion that extends above the floor surface. A plurality of protrusions extend radially from the center portion and from the floor surface and are spaced apart such that a spray guide is formed between each of the spaced apart plurality of protrusions. Each of the plurality of protrusions and spray guides are tapered so to terminate prior to the rim wall such that a continuous radius portion is formed from a portion of the rim wall and a portion of the floor surface beyond a respective terminating portion of each of the plurality of protrusions and spray guides.

A diesel engine system is provided, which includes a piston having a cavity dented downwardly in a crown surface thereof and having a bottom part, a peripheral part dented so as to be convex radially outward, and a lip part formed above the peripheral part and protruding so as to be convex radially inward in a cross-sectional view. An injection controller causes an injector to perform, during operation in a given operating range, a main injection in which injected fuel is directed to the lip part, and an after-injection in which a smaller amount of the fuel than the main injection is injected at a given timing later than the main injection in an expansion stroke. An injection interval period from an end of the main injection to a start of the after-injection is shorter as a temperature parameter related to a progress of a warmup of engine increases.

A method for operating an internal combustion engine of a motor vehicle having a cylinder, the combustion chamber of which is delimited in the radial direction by a cylinder wall and in the axial direction by a piston and by a combustion chamber roof. The piston has an annularly peripheral piston stage which is arranged axially recessed in the piston compared with an annularly peripheral piston crown and which merges via an annularly jet splitter contour into a piston hollow arranged axially recessed in the piston in relation to the piston stage. An injector is allocated to the cylinder and via the injector several injection jets are simultaneously injected directly into the combustion chamber in a star shape for a combustion process.

A piston for an internal combustion engine includes a piston having a bowl surface forming a combustion bowl, a rim surface forming an annular rim, and a gallery surface exposed to a backside cooling gallery of the piston. The bowl surface forms a bowl profile varied circumferentially around a piston center axis, and the gallery surface forms a gallery profile that is varied circumferentially around the piston center axis and is congruous with the bowl profile. The gallery surface is concave to the combustion bowl, convex to the backside cooling gallery, and forms no edges exposed within the backside cooling gallery. A wall formed between the combustion bowl and the backside cooling gallery has a heat-dissipation wall thickness defined by the varied bowl profile and the varied gallery profile.

A combustion chamber structure for an engine includes a combustion chamber where SI combustion by spark ignition and CI combustion by self-ignition are conducted. A crown surface includes a cavity recessed to have a bowl-shape; a pair of first raised portions having a mound-shape along a pent roof shape; and a second raised portion provided to protrude at a position orthogonal to a ridge extending direction of the pair of first raised portions. With a height of the first raised portion relative to a height position of a deepest portion of the cavity being represented as H1 and a height of the second raised portion being represented as H2, H1/H2 as a ratio of the height H1 of the first raised portion to the height H2 of the second raised portion is set to be in a range of 1.92 or more and 2.75 or less.

A diesel engine system is provided, which includes a piston having a cavity dented downwardly in a crown surface thereof and having a bottom part, a peripheral part dented so as to be convex radially outward, and a lip part formed above the peripheral part and protruding so as to be convex radially inward in a cross-sectional view. An injection controller causes an injector to perform, during operation in a given operating range, a main injection in which injected fuel is directed to the lip part, and an after-injection in which a smaller amount of the fuel than the main injection is injected at a given timing later than the main injection in an expansion stroke. An injection interval period from an end of the main injection to a start of the after-injection is shorter as a temperature parameter related to a progress of a warmup of engine increases.