Abstract: Internal combustion engines having pistons with one or more depressions located on the piston head to facilitate the movement of air/charge in the cylinder are disclosed. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston head also may be domed to further facilitate the movement of air/charge in the cylinder. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves, and may include a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

Abstract: An improved method and means for increasing the efficiency and power output of combustion engines, fluid power devices and other force transmitting applications. Pressure wave inversion details are provided to increase fluid flow and applied force while reducing friction and wear. The speed of combustion is also significantly increased which improves fuel economy, emissions and engine performance.

Abstract: When an amount of a backward tumble flow is smaller than an amount of a forward tumble flow, the intake-side valve recess is used as a first valve recess and the exhaust-side valve recess is used as a second valve recess. When the amount of the backward tumble flow is larger than the amount of the forward tumble flow, the exhaust-side valve recess is used as a first valve recess and the intake-side valve recess is used as a second valve recess. An inclination angle of the first valve recess is larger than an inclination angle of the second valve recess when comparing the inclination angle such that a height of the recess decreases gradually toward an inner side of a cross-section.

Abstract: A combustion chamber structure for a spark-ignition internal combustion engine includes a combustion chamber, an ignition plug, and a guide portion. The combustion chamber is configured to produce tumble flow that swirls in an axial direction of a cylinder. The ignition plug is disposed in a central portion of an upper wall of the combustion chamber. The guide portion protrudes from the upper wall of the combustion chamber, and is configured to guide airflow passing through the central portion of the combustion chamber in an intake-exhaust direction of the combustion chamber while dispersing the airflow around the guide portion.

Abstract: The present invention relates to an internal combustion engine. An object of the invention is to allow an effect produced by an anodic oxide film to be exerted while suppressing a decrease in the combustion rate. A piston 10 includes a cavity portion 20 and a tapered portion 26 that is formed so as to surround the cavity portion 20 on an outer side thereof. The diameter of the tapered portion 26 decreases progressively in the downward direction from the top face side of the piston. A squish portion 28 is formed on an outer side of the tapered portion 26. An anodic oxide film 30 is formed on a surface (tapered face) of the tapered portion 26 and a surface (squish face) of the squish portion 28. The anodic oxide film 30 is not formed on the surface (cavity face) of the cavity portion 20.

Abstract: An internal combustion engine includes an engine assembly that defines a bore, and a piston disposed and moveable within the bore. The piston and the engine assembly cooperate to define a combustion chamber therebetween. A direct injection fuel system directs a fuel spray into the combustion chamber along a linear path. The combustion chamber includes a contoured surface having a plurality of annular recesses. The contoured surface divides and re-directs the fuel spray from the linear path into each of the annular recesses to form a plurality of independent rotating vortices.

Abstract: A combustion chamber of an internal combustion engine includes a contoured surface that defines a plurality of deflection foils. The contoured surface distributes fuel spray into portions directed toward one of the deflection foils. Each deflection foil re-directs their respective portion of the fuel spray into a combined radial path that swirls about a center of the combustion chamber. Each of the deflection foils defines a flow path and a foil axis. The flow path includes an entrance segment and an exit segment. The entrance segment directs a portion of the fuel spray radially away from the center of the combustion chamber, and the exit segment directs the portion of the fuel spray substantially tangential relative to the combined radial path of the re-directed portions of the fuel spray.

Abstract: Disclosed is a piston (16) that is capable of not only suppressing the occurrence of knocking but also reducing cooling loss in an internal combustion engine in which a tumble flow is formed in a cylinder. The piston for the internal combustion engine in which the tumble flow is formed in the cylinder includes a non-adiabatic region (50) that is a region on a piston upper surface (35) brought into contact with the tumble flow during an intake stroke and has no insulating layer. The piston also includes an adiabatic region (52) that is a region on at least a part of the piston upper surface excluding the non-adiabatic region and has an insulating layer.

Abstract: An internal combustion engine includes a combustion chamber defined by a cylinder, a piston defining a piston top, a cylinder head with an intake port and an exhaust port, and a corresponding intake valve and an exhaust valve. The internal combustion engine further includes an intake manifold for supplying air to the combustion chamber and an exhaust manifold for drawing exhaust gas from the combustion chamber. The flow dynamics of the internal combustion engine are improved by including textured surfaces on one or more of the piston top, the cylinder head, the intake valve, the intake port, the exhaust valve, the intake manifold, the exhaust manifold, or the fuel supplier. The textured surface may include indentations, protrusions, or combinations.

Abstract: A piston for a four valve direct injection diesel engine defines a combustion chamber comprising a recess (10) in the piston crown, which is rotationally symmetrical about the axis of the piston in axial cross-section and is defined by a base and a side wall. A generally conical projection (5) is upstanding from the base. The recess (10) includes a lower toroidal portion (8) and an upper portion (10), whose diameter progressively increases towards the piston crown. The upper and lower portions of the recess are separated by an annular, arcuate lip (12) extending into the recess.

Abstract: A direct fuel-injection engine includes a piston, a cavity recessed in a central part of a top face of the piston, and a fuel injector. At a main injection collision point of a fuel-injection axis when main injection is performed while the piston is near top dead center, a main injection collision angle formed between its tangent and the fuel-injection axis is set at an obtuse angle. Fuel colliding with the main injection collision point is deflected towards a cavity open end side. At a secondary injection collision point of the fuel-injection axis when performing secondary injection with the piston is further from top dead center, a secondary injection collision angle formed between its tangent and the fuel-injection axis is set at one of a right angle and an acute angle. Fuel colliding with the secondary injection collision point is deflected primarily in the circumferential direction of the 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 and a dome that defines a volume configured to receive a fuel-air mixture, the inner surface of the bowl and the dome each including at least one surface feature as a target for the fuel spray. 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: An engine assembly includes an engine structure including an engine block defining a cylinder bore and a cylinder head, a piston located in the cylinder bore, and a camshaft assembly. The piston, cylinder head, and cylinder bore cooperate to define a combustion chamber including first and second longitudinal end surfaces defined by the cylinder head and the piston. A first protrusion may extend longitudinally from one of the first and second longitudinal end surfaces and radially inward from a circumference of the combustion chamber to a location between a first intake port and a first exhaust port in communication with the combustion chamber. The camshaft assembly may include a first intake lobe that opens a first intake valve and a second intake lobe that opens a second intake valve. The first intake lobe may be rotationally offset from the second intake lobe in a rotational direction of the camshaft assembly.

Abstract: In a cross section in which squish flow from an outer peripheral part of a piston (13) toward a cavity (25) is large due to a width (W2) of a squish area (SA) being large and a squish clearance (C2) being small, a collision angle (?2) at which a fuel injection axis (Li2) collides with the cavity (25) is made large, whereas in a cross section in which squish flow is small due to the width of the squish area (SA) being small and the squish clearance being large, the collision angle at which a fuel injection axis collides with the cavity (25) is made small. This enables a tendency for fuel to flow out to the exterior of the cavity (25) in a cross section where the squish flow is small to be weakened, and a tendency for fuel to flow out to the exterior of the cavity (25) in a cross section where the squish flow is large to be strengthened, thereby making the conditions in which fuel and air are mixed uniform throughout the entire region of the cavity (25).

Abstract: An engine assembly may include an engine structure, a piston, and a direct injection fuel system. The engine structure may define a cylinder bore and an intake port in communication with the cylinder bore and adapted to mitigate intake air swirl within the cylinder bore. The piston may be disposed within the cylinder bore for a reciprocal stroke between a top dead center position and a bottom dead center position. The piston may define an annular recess portion in an axial end surface thereof. The direct injection fuel system may include a fuel injector that provides a fuel spray to a combustion chamber defined by the piston and the cylinder bore. The fuel spray may define an annular plume intersecting the annular recess portion in the piston when the piston is in an injection position within twenty percent of the reciprocal stroke from the top dead center position.

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 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 that forms at least one edge portion as a target for the fuel spray, the edge portion defined by two or more surface portions. 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: In a direct fuel injection diesel engine having a piston with a pentroof-shaped top face, with regard to a pentroof-shaped piston (13) with a cavity (25) recessed in a central part of the top face, a radial width S of a squish area (26) formed between an outer peripheral part of the top face and a lower face of a cylinder head (14) changes in the circumferential direction of the piston (13). By setting a squish clearance H large for a portion where the radial width S of the squish area (26) is large and setting the squish clearance H small for a portion where the radial width S of the squish area (26) is small, more specifically, by setting S/H so that it is constant in the circumferential direction, it is possible to make the strength of the squish flow uniform in the circumferential direction of the piston, thus promoting the mixing of air and fuel and reducing harmful exhaust components.

Abstract: An engine assembly may include an engine structure, a piston, and a direct injection fuel system. The engine structure may define a cylinder bore and an intake port in communication with the cylinder bore and adapted to mitigate intake air swirl within the cylinder bore. The piston may be disposed within the cylinder bore for a reciprocal stroke between a top dead center position and a bottom dead center position. The piston may define an annular recess portion in an axial end surface thereof. The direct injection fuel system may include a fuel injector that provides a fuel spray to a combustion chamber defined by the piston and the cylinder bore. The fuel spray may define an annular plume intersecting the annular recess portion in the piston when the piston is in an injection position within twenty percent of the reciprocal stroke from the top dead center position.

Abstract: In a direct fuel injection diesel engine equipped with a pentroof-shaped piston, when fuel is injected into a cavity (25) recessed in a central part of a piston (13), for which the height of a top face changes in the circumferential direction, from a fuel injection point (Oinj) of a fuel injector disposed on a piston central axis along a plurality of fuel injection axes (Li1,Li2), if a cross-section of the cavity (25) passing along the fuel injection axis (Li1,Li2) is defined as a fuel injection cross-section (Sn), a cross-sectional shape (see shaded portion) of the cavity (25) defined by first to third specific points (An, Bn, Cn) on the fuel injection cross-section (Sn) is set so as to be substantially equal for each fuel injection cross-section (Sn). By so doing, the conditions in which fuel and air are mixed in each fuel injection cross-section (Sn) can be made uniform, the engine output can be improved, and harmful exhaust substances can be reduced.

Abstract: A piston of a gasoline direct engine may include a protuberance portion protruding along a circular arc shape having a radius (R1) equal to the piston diameter to have a predetermined height (T) from the upper surface thereof, and the edge of the protuberance portion is rounded to be connected with the upper surface; a bowl (B) having a bottom surface (F1) having an asymmetrical ellipse shape from the center of the protuberance portion to the intake side direction thereof, wherein the bottom surface thereof becomes deeper in the exhaust side direction to have a predetermined slope angle (?1), and the inner wall portion thereof has a circular arc shape to form a predetermined rising angle (?2) at the upper part thereof; and trumpet portions (TR) of which edge ends (E) thereof are expanded in the intake side direction of the protuberance portion to be connected to the bowl (B).

Abstract: Passageways are provided within the combustion chamber of a fuel injected internal combustion engine to convey injected fuel to desired positions within the combustion chamber. The fuel-conveying passageways may be either open-sided or closed, and are positioned within the combustion chamber in substantial alignment with a respective spray jet of fuel, enabling optimum distribution of the fuel through the combustion chamber for enhanced mixing with air prior to combustion.

Abstract: An internal combustion engine can include a combustion volume within a cylinder of an internal combustion engine. The combustion volume can be defined at least by a cylinder wall and a first piston in the cylinder. A swirl port can deliver a fluid into the combustion volume via a swirl port outlet such that the delivered fluid is directed around a periphery of the cylinder with a fluid velocity disposed at a predetermined angle away from tangential to a curve of the cylinder wall to generate a swirling motion in the combustion volume.

Abstract: In a direct fuel injection diesel engine equipped with a pentroof-shaped piston, a collision angle (?) at which fuel injected in a direction in which the height of the top face of a piston (13) is high collides with a cavity (25) is set larger than a collision angle (?) at which fuel injected in a direction in which the height of the top face of the piston (13) is low collides with the cavity (25).

Abstract: A piston top surface (23) has a depression. A center region (28A) is formed at the center of the depression to secure the diameter of a center tumble flow to be large. A side region (28B) is formed on both sides of the piston top surface to generate a side tumble flow that is not influenced by a cylinder bore inner wall and has a flow line generally parallel to that of the center tumble flow.

Abstract: A reciprocating internal combustion engine. The present invention improves the spark ignition facility used by the engine inventions described in patent publications WO2005/052335 and WO2007/080366 by providing a device to ensure reliable spark ignition by protecting the spark plug from malfunction by sooting.

Abstract: In a direct fuel injection diesel engine equipped with a pentroof-shaped piston, when fuel is injected into a cavity (25) recessed in a central part of a piston (13), for which the height of a top face changes in the circumferential direction, from a fuel injection point (Oinj) of a fuel injector disposed on a piston central axis along a plurality of fuel injection axes (Li1,Li2), if a cross-section of the cavity (25) passing along the fuel injection axis (Li1,Li2) is defined as a fuel injection cross-section (Sn), a cross-sectional shape (see shaded portion) of the cavity (25) defined by first to third specific points (An, Bn, Cn) on the fuel injection cross-section (Sn) is set so as to be substantially equal for each fuel injection cross-section (Sn). By so doing, the conditions in which fuel and air are mixed in each fuel injection cross-section (Sn) can be made uniform, the engine output can be improved, and harmful exhaust substances can be reduced.

Abstract: A piston of a gasoline direct engine may include a protuberance portion protruding along a circular arc shape having a radius (R1) equal to the piston diameter to have a predetermined height (T) from the upper surface thereof, and the edge of the protuberance portion is rounded to be connected with the upper surface; a bowl (B) having a bottom surface (F1) having an asymmetrical ellipse shape from the center of the protuberance portion to the intake side direction thereof, wherein the bottom surface thereof becomes deeper in the exhaust side direction to have a predetermined slope angle (?1), and the inner wall portion thereof has a circular arc shape to form a predetermined rising angle (?2) at the upper part thereof; and trumpet portions (TR) of which edge ends (E) thereof are expanded in the intake side direction of the protuberance portion to be connected to the bowl (B).

Abstract: A reciprocating piston engine wherein the movement of a piston within the combustion chamber creates vortices in the fluid within the chamber and wherein the orientation of the vortices is more normal to the axis of movement of the piston than parallel to the axis of movement of the piston. The vortices may be created by a device for attachment to the crown of a piston or by the configuration of the crown of the piston. The vortices may be created by a plurality of vanes extending outwardly from the center of the piston to the periphery thereof.

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: The invention provides an in-cylinder injection type internal combustion engine that is capable of controlling gas flow velocity in the vicinity of an ignition part of a spark plug and maintaining an air-fuel mixture suitable for ignition for a long time. The engine includes deflecting parts 28 that have a passage 25 located on a wall face of a combustion chamber between an injection part 11 and an ignition part 17, and deflect a portion of the fuel injected from the injection part 11 to indirectly direct the fuel to the vicinity of the ignition part. Due to the above construction, there is a difference in reaching timing between direct and indirect routes, and moreover a flow velocity of gas that reaches the ignition part is reduced by fuel deflection. An air-fuel mixture suitable for ignition therefore remains in the vicinity of the ignition part for a long time.

Abstract: A piston top surface (23) has a depression. A center region (28A) is formed at the center of the depression to secure the diameter of a center tumble flow to be large. A side region (28B) is formed on both sides of the piston top surface to generate a side tumble flow that is not influenced by a cylinder bore inner wall and has a flow line generally parallel to that of the center tumble flow.

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: In a direct fuel injection diesel engine having a piston with a pentroof-shaped top face, with regard to a pentroof-shaped piston (13) with a cavity (25) recessed in a central part of the top face, a radial width S of a squish area (26) formed between an outer peripheral part of the top face and a lower face of a cylinder head (14) changes in the circumferential direction of the piston (13). By setting a squish clearance H large for a portion where the radial width S of the squish area (26) is large and setting the squish clearance H small for a portion where the radial width S of the squish area (26) is small, more specifically, by setting S/H so that it is constant in the circumferential direction, it is possible to make the strength of the squish flow uniform in the circumferential direction of the piston, thus promoting the mixing of air and fuel and reducing harmful exhaust components.

Abstract: A reciprocating piston engine wherein the movement of a piston within the combustion chamber creates vortices in the fluid within the chamber and wherein the orientation of the vortices is more normal to the axis of movement of the piston than parallel to the axis of movement of the piston. The vortices may be created by a device for attachment to the crown of a piston or by the configuration of the crown of the piston. The vortices may be created by a plurality of vanes extending outwardly from the center of the piston to the periphery thereof.

Abstract: A reciprocating piston engine wherein the movement of a piston within the combustion chamber creates vortices in the fluid within the chamber and wherein the orientation of the vortices is more normal to the axis of movement of the piston than parallel to the axis of movement of the piston. The vortices may be created by a device for attachment to the crown of a piston or by the configuration of the crown of the piston. The vortices may be created by a plurality of vanes extending outwardly from the center of the piston to the periphery thereof.

Abstract: A reciprocating internal-combustion engine having at least two gas intake ports (3) with gas intake valves (6), at least one gas exhaust port (4) with a gas exhaust valve (7) and at least one ignition device (14) per cylinder (1) is provided. The engine can also include a combustion chamber (1.1) formed by a cylinder cover (2.1) and a crown (11.1) of a piston (11). A trough-shaped recess (12) can be provided in the piston crown (11.1) and is bounded by a trough base (12.1) and side walls (16). The recess (12) can intersect a roof ridge (11.2) on the piston crown (11.1) and the trough base (12.1) slopes towards a fuel injection nozzle (8) and ends in a wall zone (12.2) extending steeply upwards on its side facing the fuel injection nozzle (8).

Abstract: A piston in a direct injection spark ignition internal combustion engine is configured to reciprocate upward and downward within a combustion chamber along a reciprocating axis. The piston comprises an upper end which partly defines the combustion chamber; a bowl defined on the upper end of the piston, the bowl having an at least partially curved sidewall region extending upward from a bottom surface of the bowl, the bowl being configured so that fuel injected laterally into the bowl toward the curved sidewall region from an injection side of the bowl is directed along the curved sidewall region and upward toward a spark plug of the internal combustion engine, where the bowl has a converging contour in which a curvature of the converging contour is greater at a portion of the contour near the spark plug than a portion of the contour near the injection side of the bowl.

Abstract: An internal combustion engine has a pair of opposed pistons held within an elliptical guide of the engine housing. The pistons reciprocate within a cylinder attached to a shaft. A combustion chamber is formed within the shaft and positioned to be between the pistons. Combustion of fuel causes the pistons to reciprocate and reciprocation of the piston causes rotation of the shaft. A valve having an intake and out take port provide fuel and exhaust to the combustion chamber. A bridge extending upwardly form the bottom of the combustion chamber prevents fuel intake from exiting the exhaust before combustion.

Abstract: An in-cylinder injection, spark ignited internal combustion engine including a fuel injection valve spraying fuel substantially in a sector having a relatively small thickness and spreading substantially vertically to implement homogenous combustion and stratified combustion, ensures that for stratified combustion a large portion of the sprayed fuel is injected into a cavity and thus sufficiently vaporized and positioned as a combustible air fuel mixture in a vicinity of an ignition plug. A fuel injection valve is arranged at a perimeter of an upper portion of the cylinder and a piston has a top surface provided with a cavity biased in location to be farther from the fluid injection valve and having a wall opposite the fuel injection valve deviating toward the cylinder's substantial center the fuel sprayed for stratified combustion through the fuel injection valve into the cavity.

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: Superior piston bowl and combustion chamber configurations are designed for a reverse tumble spark ignition direct injection engine. The piston includes a shallow bowl extending from adjacent an edge of the piston head to an inner side slightly beyond a peak. The bowl features a bowl lip re-entrant angle at the spark plug location having an open or positive re-entrant angle. On lateral edges of the bowl between the inner and outer edges, wing like extensions include negative re-entrant angles. These help contain the injected fuel within the bowl during combustion. Other features of the combustion chamber include vertical intake ports that produce a weak reverse tumbling air flow motion with a tumble ratio of about 0.6, which allows increased flow efficiency of the port. An injector spray cone angle of 90 degrees is preferred with a bowl sized to capture the spray. Various additional features are disclosed.

Abstract: A piston for an internal combustion engine is provided. The engine has an intake port through which an intake air is introduced into the cylinder in a way as to produce a swirl that travels along while whirling about an axis transversal to an axis of the cylinder. The piston has at a crown face thereof a cavity that has a part-cylindrical bottom. The cavity has a longitudinal center axis extending obliquely to a crank axis so that the longitudinal center axis of the cavity nearly coincides with an axis along which the swirl travels within the cylinder.

Abstract: A piston for an internal combustion engine, including a piston crown having a central axis, and a piston bowl disposed in the piston crown, on which two tumble flows of air are provided. The piston bowl has a generally V-shaped contour in section taken along a vertical plane intersecting the tumble flows, on which the two tumble flows are retained at an inclined state toward a central axis of the piston crown.

Abstract: A piston structure for a direct-injection, spark-ignition engine which properly stratifies a mixture adjacent to the spark plug in a stratified-combustion operation without impairing the reliable ignition of the spark plug. In the direct-injection, spark-ignition engine, the central portion of the roof of the combustion chamber is located at a higher level than its peripheral portion, the spark plug is disposed in the central portion, the fuel injector is disposed on the left side of the central portion, and the fuel injector injects fuel so that the fuel contacts the tumble flow produced in the combustion chamber in such a manner that the mixture is concentrated adjacent to the spark plug and ignited in the area in which the tumble flow turns clockwise.

Abstract: A method for operating a reciprocating-piston internal combustion engine, having an injector nozzle operable by a single valve element and configured to directly inject a fuel into a combustion chamber and having a piston including a piston crown and a piston recess, includes the steps of injecting the fuel by the injector nozzle into the combustion chamber in the form of separated jets of the fuel having different inclinations relative to a top surface of the piston crown and selectively setting the inclinations of the fuel jets depending on an engine load.

Abstract: In order to optimize combustion in a four-stroke spark-ignition engine with direct fuel injection, the conditions of charge flow are improved by providing the top surface of each piston with two longitudinal guiding ribs located at a distance from each other and a cross-guiding rib running transversely thereto, thus providing an H-shaped configuration.

Abstract: An internal combustion engine having a cylinder head body with a pentroof-shaped combustion chamber comprises a piston including a piston cavity and a caldera-shaped protrusion provided around the piston cavity, a fuel injector for injecting fuel downward to the piston cavity and a spark plug disposed obliquely in proximity to an intake valve. The piston cavity is provided on the top surface of the piston being offset on the spark plug side. Further, the caldera-shaped protrusion is slanted towards the spark plug side. Therefore, injected fuel collides against a down-slope of the piston cavity and is diffused partly towards the spark plug and partly towards the cylinder head. As a result, a locally rich air-fuel mixture is formed around the spark plug so as to enable stratified charge combustion.

Abstract: In order to optimize combustion in a four-stroke spark-ignition engine with direct fuel injection, the conditions of charge flow are improved by providing the top surface of each piston with an essentially T-shaped configuration of guiding ribs, i.e., a longitudinal rib extending transversely to the crankshaft axis running and a cross-rib running in the direction of the crankshaft axis.

Abstract: To accelerate a combustion with an entire combustion chamber including the vicinity of an opening portion for air suction to thereby make uniform a flame propagation in a combustion chamber structure for an internal combustion engine, and to provide a technology for preventing the generation of knocks, a longitudinal sectional shape of a top wall surface of the combustion chamber is in the form of a substantially triangular shape in longitudinal section defined and surrounded by a cylinder head, a cylinder and a piston. A projection is provided on a circumferential edge portion of a top surface of the piston, with a surface, facing the top wall surface of the combustion chamber, of the projection being substantially in parallel with the top wall surface of the combustion chamber. A cutaway portion is formed in the vicinity of at least a portion, facing the intake opening portion, of the projection of the top surface of the piston.