Abstract: Methods and systems are provided for operating an engine having a plurality of cylinders that utilize oil for lubrication purposes. In one embodiment, a method for the engine may include determining if one or more conditions have been met for port heating based on one or more operating conditions of the engine, continuing current operation if the one or more conditions for port heating have not been met, and determining a souping level of the engine if the one or more conditions for port heating have been met and subsequently running port heating on a set of cylinders of the engine based on the souping level of the engine and/or the one or more conditions for port heating. The engine may be a non-EGR engine and/or a high speed diesel engine. Each cylinder of the set of cylinders may have at least one port.

Abstract: A swirl chamber-type diesel engine includes a secondary combustion chamber assembly coupled to a cylinder head to define a secondary combustion chamber having, on an inner wall surface thereof, a curved swirl induction part, and a connecting passage formed at a lower end of the swirl induction part, and a piston defining a primary combustion chamber and including a trench part being in communication with the connecting passage, and clover parts formed at both sides of the trench part, in which a guide structure is provided in the connecting passage, and the guide structure divides combustion gas, discharged from the secondary combustion chamber to the primary combustion chamber, into three portions and guides the combustion gas.

Abstract: An internal combustion engine has a cylinder with a combustion chamber and a piston supported reciprocatingly in the cylinder and delimiting the combustion chamber. A crankcase is connected to the cylinder and a crankshaft is rotatably supported therein. The piston is operatively connected to the crankshaft so as to drive the crankshaft in rotation. A transfer passage provides flow communication between crankcase interior and combustion chamber when the piston is at bottom dead center. The transfer passage has a port opening connecting the transfer passage to the crankcase interior and has a transfer port connecting the transfer passage to the combustion chamber. A fuel supply device supplies fuel into the transfer passage at a location between the transfer port and the port opening. The transfer passage has a connecting opening and is connected to the crankcase interior at the connecting opening. A control element controls the connecting opening.

Abstract: A method for manufacturing a piston of an internal combustion engine from a piston upper part and a piston lower part may include producing at least the piston lower part as a forged steel part. A partial cross section of a cooling duct may be provided in the piston lower part. A closed supply inlet funnel may be forged within the piston lower part. The closed supply inlet funnel may be bored into the piston lower part from the cooling duct. A borehole may be introduced into the piston lower part obliquely to a piston axis. The piston lower part and the piston upper part may be welded to one another.

Abstract: A piston for a cylinder for an internal combustion engine has a piston bowl surface adapted for facing a combustion chamber of the cylinder, the piston bowl surface being provided with a thermal barrier coating layer, wherein the thermal barrier coating layer is provided on a plurality of circumferentially spaced surface parts of the piston bowl surface. A method for producing a piston for a cylinder for an internal combustion engine includes the steps of providing a piston for a cylinder for an internal combustion engine, the piston having a piston bowl surface adapted for facing a combustion chamber of the cylinder, and providing the piston bowl surface with a thermal barrier coating layer, wherein the step of providing the thermal barrier coating layer is made on a plurality of circumferentially spaced surface parts of the piston bowl surface.

Abstract: A method for operating a fuel injection system is provided. The method includes injecting fuel from a first direct fuel injection device arranged in a cylinder liner in a cylinder block into a combustion chamber and injecting fuel from a second direct fuel injection device arranged in a cylinder head into the combustion chamber, the first and second direct fuel injection devices arranged at an obtuse angle with regard to an intersection of central axes of the first and second direct fuel injection devices.

Abstract: A piston and an engine including the same are provided. The piston includes an upper surface that is formed at an upper portion; a bowl that is concavely formed at the upper surface; a plurality of protruding portions that are separated by a predetermined distance along an edge of the bowl; and a central portion that is protruded upward at the center of the bowl.

Abstract: A piston for a direct injection engine is provided, the piston having a bowl at an upper end, the bowl forming a portion of a combustion chamber. The bowl includes an inner surface that defines a volume configured to receive a fuel-air mixture, the inner surface of the bowl including at least one surface feature as a target for the fuel spray, the surface feature angled 20° to 80° from the piston face. The surface feature may protrude from the inner surface of the bowl or may be recessed into the inner surface. Such surface features may reduce soot and improve fuel-air mixing.

Abstract: A piston is arranged for reciprocal movement in a combustion engine cylinder. Protrusions are or a ridge is arranged half way between flame plume impingement areas in a plane perpendicular to the reciprocal movement and protrude to the combustion chamber having a smooth form adapted for preserving kinetic energy in a flame plume. The protrusion or ridge includes a left side flank, a top section and a right side flank, and a transition section between each of the side flanks and the top section, the transition section including a deflection edge in order to minimize flow losses.

Abstract: A piston for an internal combustion engine is located within a cylinder of the engine. The piston includes a dish-shaped depression in a surface of the piston exposed to a combustion chamber of the cylinder providing a recess from a nominal top of the piston. The depression includes a depression boundary located at the nominal top of the piston and proximate to an outer diameter of the piston, an apex, and inclined walls connecting the apex to the depression boundary.

Abstract: A piston for a compression ignition internal combustion engine includes a piston body having a combustion face defining a combustion bowl, and the combustion face including a compound bowl surface and a compound rim surface. The combustion face is profiled to balance a combustion efficiency property of the piston with emissions properties of the piston, and includes a profile of rotation defining a convex curve segment bisected by the longitudinal axis, and a plurality of concave curve segments outboard of the convex curve segment. The profile of rotation further includes a compound rim profile defining a plurality of convex curve segments corresponding to an inner rim surface. The convex curve segment of the compound bowl profile defines a relatively small radius of curvature, and the plurality of convex curve segments corresponding to the inner rim surface define a relatively large radius of curvature.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods to improve combustion efficiency in compression ignition, indirect injection, diesel engines, and in particularly for diesel engines having a removable pre-chamber. In all embodiments, a combustion system is fitted with a pre-chamber adapted to cooperate with a piston in a manner that produces a highly efficient combustion process. In some embodiments, the pre-chamber has passages that have a variable cross-section and a variable angular orientation with respect to a centerline of the pre-chamber body. In one embodiment, the piston is provided with a number of surfaces that improve combustion of the fuel/air mixture within the combustion chamber. In some embodiments, the piston surfaces are generally aligned with angles of the combustion chamber such as the angle of the intake and exhaust valves. In other embodiments, the piston has surfaces that are adapted to cooperate with a tip of the pre-chamber.

Abstract: A direct injection compression ignition internal combustion engine includes a fuel system having a nozzle extending into a cylinder of the engine and a plurality of spray orifices formed in the nozzle. Each of the spray orifices has an inner diameter dimension of about 0.09 mm or less, and define inter-orifice angles between adjacent spray orifice center axes of about 36° or greater such that spray plumes of injected fuel from each of the spray orifices combust within the cylinder according to a non-sooting lifted flame and gas entrainment combustion pattern. Related methodology is also disclosed.

Abstract: A piston and an engine are provided that includes various precise configuration parameters, including dimensions, shape and/or relative positioning of the combustion chamber features, resulting in a combustion process that yields improved mixing of fuel and intake air and increased uniformity of load on the engine pistons. The piston provides a piston bowl with a concave curvilinear portion that may be semi-spherical and extends inwardly to a depth; an angled surface extends inwardly from the crown surface to intersect the concave curvilinear portion at an edge at a depth; and a curved surface that extends inwardly from the crown surface to intersect the concave curvilinear portion at a tangent at a depth. The angled surface may be part of a frusto-conical surface that may extend from both sides of the angled surface to an area proximate the curved surface.

Abstract: Provided is a spark-ignition internal combustion engine capable of ensuring engine output power while setting a geometric compression ratio of an engine body to a high value. In the spark-ignition internal combustion engine, each of a clearance between a top surface (3a) of a piston (3) located at a top dead center position and a lower surface (8a) of each of two intake valves (8) in a full-closed state, and a clearance between the top surface (3a) of the piston (3) located at the top dead center position and a lower surface (9a) of each of two exhaust valves (9) in a full-closed state, is set to 5 mm or more, and a stroke length S of the piston (3) is set to satisfy the following relation: S?0.977×B+18.2, where B is a bore diameter of a cylinder.

Abstract: An internal combustion engine 100 includes a cylinder 102 that defines a combustion chamber 196 causing a premixed gas to be combusted, a piston 120 that defines the combustion chamber 196 together with the cylinder 102, and reciprocates in the cylinder 102, and an active species generator 150 that generates active species. The internal combustion engine 100 promotes combustion of the mixed gas by the active species generated by the active species generator 150. The piston 120 includes an active species generation chamber 194 that is formed therein and open to a top surface of the piston 120, and in which the active species generator 150 generates the active species.

Abstract: An engine is provided. In one embodiment, the engine includes a precombustion chamber having a body, a secondary combustion chamber disposed at least partially in the body, and a plurality of passages configured to place the precombustion chamber in fluid communication with a main combustion chamber.

Abstract: An internal combustion cyclone engine includes a gas hole, a gas hole plugging protrusion, and oblique holes. The gas hole is provided in the piston, and connects the explosion chamber with the combustion chamber. The gas hole plugging protrusion is provided in the cylinder and configured to be inserted into and seal the gas hole while the piston is pushed up. Oblique holes are provided around the gas hole through the top plate portion of the piston, and each of the oblique holes connects the explosion chamber with the combustion chamber concentrically and obliquely. At the top dead center the top plate portion of the piston almost touches the top wall portion of the cylinder. At the start of the expansion phase before ignition substantially all of the compressed gas is in the explosion chamber and whirls around inside the explosion chamber during the compression phase.

Abstract: A wall shape of a cavity consists of an inward protruding portion located at the periphery of an opening, a center portion projecting toward a fuel injector, and a peripheral portion connecting the inward protruding portion and the center portion. The fuel injector and the cavity are configured so that fuel injected from fuel injector directs to the proximity of the border between the inward protruding portion and the peripheral portion. The peripheral portion consists of a first portion located farthermost from the fuel injector, a second portion located between the inward protruding portion and the first portion, and a third portion located between the first portion and the center portion. The radii of arcs of the peripheral portion decrease from the second portion to the first portion and increase from the first portion to the third portion.

Abstract: A plurality of convex portions are radially fanned and spaced apart from each other by a constant angle in a planar view on a tapered surface of a land portion formed on a bottom surface of a cavity formed in a top portion of a piston. Each convex portion is positioned such that the extending direction of the convex portion aligns with an axis X of a corresponding fuel spray. Thereby, each fuel spray moves forward through a space (convex portion space) between the corresponding convex portion and an inner wall of a cylinder head portion along the extending direction of the corresponding convex portion. When a fuel injection is performed during the latter half of a compression stroke, a pressure in a convex portion space is increased, compared with a pressure in a space of the other portion by the decrease of a ratio of the volume of the convex portion space relative to the volume of the space of the other portion by the proceeding of the compression by the piston.

Abstract: An internal combustion engine piston having a combustion bowl with fuel control structure for redirecting at least a portion of the fuel exiting the combustion bowl. One form of the piston includes a sharp edge disposed at the outer surface of the piston adjacent the entrance to the combustion bowl and a rounded fuel receiving lip located within the combustion bowl.

Abstract: A gasoline direct injection engine that has an injector directly injecting fuel into a combustion chamber, a spark plug, an intake valve, and an exhaust valve and generates power by reciprocating a piston in a cylinder, may include a first cavity formed on a piston head of the piston to return at least some flow of the fuel injected from the injector to the spark plug, a protrusion protruding and off-set from the first cavity toward the exhaust valve, and a second cavity formed from the protrusion to the exhaust valve at a smaller height than the first cavity.

Abstract: A piston for a direct injection engine is provided, the piston having a bowl at an upper end, the bowl forming a portion of a combustion chamber. The bowl includes an inner surface that defines a volume configured to receive a fuel-air mixture, the inner surface of the bowl including a generally concave portion including a flat bottom surrounding a central protruding dome. The relatively flat bottom portion is bounded by two radial concave surface portions which are disposed below two convex separation features for the injected fuel spray. Such surface geometries may reduce soot and improve fuel-air mixing.

Abstract: A combustion system for a vehicle may include a piston in which a first combustion recess is formed in an upper end surface thereof, and at least one second combustion recess is further formed at the bottom of the first combustion recess, a first intake port and a second intake port for supplying a cylinder with air, and a controller that differently controls amounts of recirculation exhaust gas being supplied to the first intake port and the second intake port.

Abstract: There is provided a spark ignited internal combustion engine having a geometric compression ratio of 13.0 or greater. The engine comprises combustion chambers having a cylinder stroke volume of 0.3 liter or greater, with the spark plug in the chamber ceiling having its spark point in the combustion chamber, and a cavity being formed on the top surface of the piston. At least part of the cavity defines a spherical surface that a hypothetical sphere having its center at the spark point contacts when the piston is at top dead center. The cavity is formed so that V2/V1?0.31, where V1 is top-dead-center combustion chamber volume, and V2 is the volume of the part of the hypothetical sphere not interfering with the combustion chamber floor or ceiling at top dead center. The flame thus spreads with less interference, shortening combustion duration and reducing fuel consumption.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for internal combustion engines and in particularly for diesel engines having prechamber combustion systems. In one embodiment, a combustion system can be provided with a pre-chamber adapted to cooperate with a piston in a manner that produces a highly efficient combustion process. In some embodiments, the pre-chamber has passages that have a variable cross-section and a variable angular orientation with respect to a centerline of the pre-chamber body. In one embodiment, the piston is provided with a number of surfaces that facilitate the flow of fuel and air within the combustion chamber. In some embodiments, the piston surfaces are generally aligned with angles of the combustion chamber such as the angle of the intake and exhaust valves. In other embodiments, the piston has surfaces that are adapted to cooperate with a tip of the prechamber.

Abstract: An engine is provided. In one embodiment, the engine includes a precombustion chamber having a body, a secondary combustion chamber disposed at least partially in the body, and a plurality of passages configured to place the precombustion chamber in fluid communication with a main combustion chamber.

Abstract: A combustion chamber in an engine includes a piston and an injector with plurality of orifices arranged to inject spray/flame plumes, which impinge on a piston outer bowl section during most of the injection. Between spray/flame plume impingement areas and in a plane substantially perpendicular to reciprocal piston movement are arranged a first type of protrusions protruding into the combustion chamber, having a smooth form for preserving kinetic energy in the flame and for redirecting circumferential flame progress mainly towards a center axis of the piston with minimal flame-to-flame interaction. A second type of protrusions are arranged in the impingement areas, being adapted for redirecting flame progress into a circumferential flame progress direction in a plane substantially perpendicular to the reciprocal piston movement and with minimal flame-to-piston wall interaction and minimal kinetic energy loss.

Abstract: A plurality of convex portions are radially fanned and spaced apart from each other by a constant angle in a planar view on a tapered surface of a land portion formed on a bottom surface of a cavity formed in a top portion of a piston. Each convex portion is positioned such that the extending direction of the convex portion aligns with an axis X of a corresponding fuel spray. Thereby, each fuel spray moves forward through a space (convex portion space) between the corresponding convex portion and an inner wall of a cylinder head portion along the extending direction of the corresponding convex portion. When a fuel injection is performed during the latter half of a compression stroke, a pressure in a convex portion space is increased, compared with a pressure in a space of the other portion by the decrease of a ratio of the volume of the convex portion space relative to the volume of the space of the other portion by the proceeding of the compression by the piston.

Abstract: Disclosed is an internal combustion engine, which has a geometric compression ratio of 13.0 or greater, and a combustion chamber (4) configured to satisfy a condition of S/V2?0.12 (mm?1) when a radius r of a hypothetical sphere (IS) with its center at an ignition point (CP) of a spark plug (3) is set to satisfy a condition of V2=0.15×V1, where: S (mm2) is an area of an interference surface between the hypothetical sphere (IS) and an inner wall of the combustion chamber (4) in a state when a piston (30) is at its top dead center position; V1 (mm3) is a volume of the combustion chamber 4 in the state when the piston (30) is at the top dead center position; and V2 (mm3) is a volume of a non-interference part of the hypothetical sphere (IS) which is free of interference with the inner wall of the combustion chamber (4) when the piston (30) is at the top dead center position. The internal combustion engine of the present invention can more reliably improve fuel economy.

Abstract: There is provided a spark ignited internal combustion engine having a geometric compression ratio of 13.0 or greater. The engine comprises combustion chambers having a cylinder stroke volume of 0.3 liter or greater, with the spark plug in the chamber ceiling having its spark point in the combustion chamber, and a cavity being formed on the top surface of the piston. At least part of the cavity defines a spherical surface that a hypothetical sphere having its center at the spark point contacts when the piston is at top dead center. The cavity is formed so that V2/V1?0.31, where V1 is top-dead-center combustion chamber volume, and V2 is the volume of the part of the hypothetical sphere not interfering with the combustion chamber floor or ceiling at top dead center. The flame thus spreads with less interference, shortening combustion duration and reducing fuel consumption.

Abstract: The invention relates to a shape of a combustion chamber for a direct-injection diesel engine, in which a mixture in, particularly, an expansion stroke is promoted by optimally designing the shape of the combustion chamber, and further, the compatibility between PM reduction and NOx reduction can be achieved by improving a retardation limit and speeding up combustion at a high EGR. The inside of a combustion chamber 12 formed at a top of a piston is formed in such a manner that a vertically cross-sectional shape passing a center axis O2 inside of the combustion chamber is symmetric with respect to the center axis. Furthermore, an opening 18 at an upper end of the combustion chamber 12 is formed into a substantially polygonal shape in combination of round portions 21 and straight portions 22.

Abstract: A piston for a diesel engine has a crown and a three-dimensional shape defined in an x-y-z coordinate space. The z-axis generally defines a cylinder axis of the piston, and the plane z=0 generally intersects an upper rim of the crown. The piston includes a combustion bowl recessed in the crown. The combustion bowl has a center point on the z-axis and has a two-dimensional partial cross-sectional configuration defined by a peripheral line connecting coordinate points (xi,yi,zi) in the x-y-z coordinate space. The (xi,yi,zi) coordinate points include points from a coordinate set S. The combustion bowl has a three-dimensional axisymmetric configuration defined by rotating the peripheral line 360° about the z-axis.

Abstract: The invention relates to a combustion recess in the head of a piston for a diesel engine, the piston being provided with a cooling duct optionally existing in the form of a cooled ring carrier. This combustion recess has, in the radially outer edge area, an undercut which is formed such that the radially outer delimitation of the combustion recess is situated sufficiently near the cooling duct so that the cooling duct has a cooling effect upon the combustion recess.

Abstract: Otto cycle internal combustion engine, comprising a cylinder block including at least one cylinder having a longitudinal axis, a piston movable within said cylinder and having a recess open on a head surface of the piston, a head fastened to said cylinder block and having a surface facing the cylinder, three intake valves and two exhaust valves movable along respective rectilinear directions, a combustion chamber delimited at one side by a portion of the surface of the head facing the cylinder and, at the other side, by the surface of said recess of the piston. The directions of motion of the valves are parallel to each other, the surface of the head facing the cylinder is planar and orthogonal to the directions of motion of the valves and the combustion chamber is obtained exclusively in the piston.

Abstract: A geometry for an IC combustion chamber is disclosed that increases the air-fuel mixing efficiency within the chamber. The piston head includes a squish surface portion for generating a squish jet, and a bowl portion that cooperatively with the cylinder head defines a combustion volume. A horizontal channel extends between the squish surface portion and the bowl portion, and is adapted to provide a high-momentum jet into the bowl portion. A transverse channel may also be provided that directs the squish flow toward the horizontal channel, thereby generating a toroidal vortex therein. A premix fuel injector may inject fuel near the upstream end of the horizontal channel. A converging nozzle portion near the distal end of the horizontal channel may increase the flow speed into the bowl portion. A chamber fuel injector is disposed near the downstream end of the horizontal channel.

Abstract: A piston for an internal combustion engine has an upper crown with a top and a bottom surface, and a lower crown with a top and a bottom surface. The upper crown and the lower crown are fixedly attached to each other using welds, with the bottom surface of the upper crown and the top surface of the lower crown forming a mating surface. The piston also has at least one centrally located air gap formed on the mating surface. The air gap is sealed to prevent substantial airflow into or out of the air gap.

Abstract: Otto cycle internal combustion engine, comprising a cylinder block including at least one cylinder having a longitudinal axis, a piston movable within said cylinder and having a recess open on a head surface of the piston, a head fastened to said cylinder block and having a surface facing the cylinder, three intake valves and two exhaust valves movable along respective rectilinear directions, a combustion chamber delimited at one side by a portion of the surface of the head facing the cylinder and, at the other side, by the surface of said recess of the piston. The directions of motion of the valves are parallel to each other, the surface of the head facing the cylinder is planar and orthogonal to the directions of motion of the valves and the combustion chamber is obtained exclusively in the piston.

Abstract: Otto cycle internal combustion engine, comprising a cylinder block including at least one cylinder having a longitudinal axis, a piston movable within said cylinder and having a recess open on a head surface of the piston, a head fastened to said cylinder block and having a surface facing said cylinder, a plurality of valves movable along respective rectilinear directions and co-operating with respective valve seats situated in said head, and a combustion chamber delimited at one side by a portion of the surface of the head facing the cylinder and, at the other side, by the surface of said recess of the piston. The engine comprises a single intake valve and two exhaust valves. The intake valve has significantly larger diameter than that of the two exhaust valves.

Abstract: A combustion chamber (20) opening toward a cylinder head (5) is provided on a top surface (11) of a piston (10), and this combustion chamber (20) comprises a first volume (22) having an inclined surface (20) and a second volume (23) further recessed from the first volume (22) toward a pin boss (13). Fuel spray F from a fuel injection nozzle (9) is injected toward an inner peripheral wall section (24) of the second volume (23) in a former stage of fuel injection and toward the inclined surface (21) of the first volume (22) in a later stage of fuel injection, and the percentage of the fuel injection period in the former stage against the total fuel injection period is set to the range from 40% to 70%.

Abstract: In an internal combustion engine with auto-ignition in which the fuel is injected directly into the combustion chamber by means of a fuel injection nozzle in the form of multiple fuel jets, wetting of the combustion chamber-side cylinder head surface is minimized by recesses formed in the cylinder head whereby some of the fuel is reflected by the piston towards the cylinder head when the piston is in a position adjacent the cylinder head and directed at least partially into the recesses formed in the cylinder head.

Abstract: A combustion engine with compression-initiated combustion comprises at least one cylinder in which a piston is movable axially between a lower dead center point and an upper dead center point, with a dead volume between the cylinder and the piston at the upper dead center point. The dead volume comprises at least two substantially separate spaces in the piston and/or the cylinder at the upper dead center point which are designed to ensure that combustion is initiated at different times.

Abstract: A combustion chamber assembly for use in a diesel engine includes a combustion chamber being defined intersecting a crown of a piston, the combustion chamber being defined by a first curved surface having a reentrancy formed proximate a first curved surface first end and having a post formed proximate a first curved surface second end, a corner being formed at a juncture of the first curved surface second end and the post, adjacent surfaces being direct smooth junctures. A piston and a method of forming a combustion chamber are further included.

Abstract: The invention relates to an internal combustion engine with spark ignition and direct fuel injection. The inventive engine comprises: a cylinder; a cylinder head; a piston which is mounted to slide in the cylinder; a combustion chamber which is defined in the cylinder between the cylinder head and the piston; a fuel injector which opens into the combustion chamber; a spark plug; inlet and exhaust valves; and a fuel injection pump which supplies the injector with a flow of pressurized fuel. According to the invention, the pressure of the fuel flow supplied to the injector exceeds 300 bar and, preferably, reaches or exceeds 500 bar.

Abstract: A piston for an internal combustion engine is disclosed. A bowl-shaped recess is constructed in the combustion face of the piston. The recess has a w-shaped cross-section. The w-shaped cross-section is unsymmetrical and has at least one side that is mostly vertical. The recess is positioned off-center in the face of the piston so that fuel that is injected into the cylinder is redirected by the recess toward a center space of the cylinder thereby improving combustion of fuel in the cylinder and preventing fuel from accumulating about a periphery of the combustion chamber.

Abstract: In an internal combustion engine having direct injection and spark ignition, charging air is introduced in stratified charge operation through one of two valve-controlled intake channels into a cylinder having a roof-like cylinder head end and a piston having a piston head with a recess oriented toward the intake side. The charging air is introduced forms a swirl flow, into which fuel is introduced. To avoid fuel accumulation on the recess wall, a strong swirl flow with a compact swirl core is achieved through a flow-optimized filling channel, with the swirl core being held in a fixed position in a rotor recess at the latest in the second section of the stroke of the piston toward top dead center such that fuel introduced into the swirl core with a relatively late end of the injection is supplied to an ignition device due to the piston movement toward top dead center.

Abstract: An direct fuel injection spark ignition internal combustion engine comprises a fuel injection valve arranged at a substantially center part of an upper are of a combustion chamber, and a piston having a crown surface with a cavity shaped so that a center axis of a substantially conical-shaped fuel stream injected from the fuel injection valve is substantially coincident with a center axis of the piston. In a low-load stratified combustion operating region when spark ignition is executed, the fuel injection angle is increased to form a first combustible air-fuel mixture before the fuel stream collides against the cavity of the piston crown surface. In a high-load stratified combustion operating region, the fuel injection angle is reduced to form a second combustible air-fuel mixture after the fuel stream collides against the cavity of the piston crown surface.

Abstract: A state of combustion in a combustion chamber is controlled by stratifying an intake gas charge within the combustion chamber, so as to reduce amounts of harmful substances left in exhaust gas. A direct-injection type internal combustion engine in which a fuel is injected into the combustion chamber and which is arranged to stratify the intake gas charge within the combustion chamber (1) such that intake gases of different compositions exist in a central portion (13) of the combustion chamber including a position of the fuel injection, and in a peripheral portion of the combustion chamber, upon initiation of combustion of the fuel at a point of time near a terminal period of a compression stroke. The intake gases of different compositions may be intake gases having different concentrations of a specific component such as recirculated exhaust gas and the fuel.

Abstract: A combustion chamber assembly for use in a piston of a diesel engine includes a combustion chamber being defined intersecting a crown of the piston, the combustion chamber being substantially defined by three surfaces, a post being in part a spherical surface, a bottom and first side portion being an annular surface, and a second side portion being a taper surface, the combustion chamber having at least three reentrancies. A piston incorporating the combustion chamber assembly and a method of forming the combustion chamber are further included.

Abstract: A piston for an internal combustion engine is disclosed. A bowl-shaped recess is constructed in the combustion face of the piston. The recess has a w-shaped cross-section. The w-shaped cross-section is unsymmetrical and has at least one side that is mostly vertical. The recess is positioned off-center in the face of the piston so that fuel that is injected into the cylinder is redirected by the recess toward a center space of the cylinder thereby improving combustion of fuel in the cylinder and preventing fuel from accumulating about a periphery of the combustion chamber.