Abstract: A control apparatus is provided for a four stroke cylinder direct-injection internal combustion engine having a cylinder and a piston disposed within the cylinder. The control apparatus includes a variable compression ratio mechanism for variably controlling the engine compression ratio by changing the top dead center position of the piston and a fuel injection device for injecting fuel directly into the cylinder. When the actual compression ratio of the engine is higher than a target compression ratio, the variable compression ratio mechanism reduces the compression ratio, and in accordance with the reduction in the compression ratio, the fuel injecting device injects an intake fuel injection amount in the intake stroke and a compression fuel injection amount in the compression stroke, and the timing for starting the fuel injection in the compression stroke is retarded.

Abstract: A multi-link engine has a piston coupled to a crankshaft to move inside an engine cylinder. A piston pin connects the piston to an upper link, which is connected to a lower link by an upper link pin. A crank pin of the crankshaft rotatably supports the lower link thereon. A control link pin connects the lower link to one end of a control link, which is connected at another end to the engine block body by a control shaft. The crank pin has a center arranged on a straight line joining centers of the upper link pin and the control link pin such that an angle formed between the straight line and a horizontal axis that is perpendicular to a center axis of the cylinder and that passes through an axial center of a crank journal is the same for at top dead center and at bottom dead center.

Abstract: A multi-link engine has a piston coupled to a crankshaft to move inside an engine cylinder. A piston pin connects the piston to an upper link, which is connected to a lower link by an upper link pin. A crank pin of the crankshaft rotatably supports the lower link thereon. A control link pin connects the lower link to one end of a control link, which is connected at another end to the engine block body by a control shaft. The upper link has an upper link axis that forms an angle with the cylinder axis, as viewed along a crank axis direction of the crankshaft, such that the angle reaches a minimum when a crank angle of the engine is within a range where the bottom end of a piston skirt is positioned below a topmost part of the bottom end of the cylinder liner.

Abstract: A multi-link engine has a piston that moves inside a cylinder. A piston pin connects the piston to an upper link, which is connected to a lower link. A crank pin of a crankshaft supports the lower link thereon. The lower link is pivotally connected to one end of a control link, which is connected at another end to the engine block body by a control shaft. The control shaft is lower than a crank journal of the crankshaft, and disposed on a first side of a plane that is parallel to a cylinder center axis and that contains a center rotational axis of the crank journal. The cylinder center axis is located on a second (i.e., opposite the first side) plane. The control link has a center axis that is parallel to the cylinder center axis when the piston is near top and bottom dead centers.

Abstract: A control apparatus is provided for a four stroke cylinder direct-injection internal combustion engine having a cylinder and a piston disposed within the cylinder. The control apparatus includes a variable compression ratio mechanism for variably controlling the engine compression ratio by changing the top dead center position of the piston and a fuel injection device for injecting fuel directly into the cylinder. When the actual compression ratio of the engine is higher than a target compression ratio, the variable compression ratio mechanism reduces the compression ratio, and in accordance with the reduction in the compression ratio, the fuel injecting device injects an intake fuel injection amount in the intake stroke and a compression fuel injection amount in the compression stroke, and the timing for starting the fuel injection in the compression stroke is retarded.

Abstract: A multi-link engine has a piston coupled to a crankshaft to move inside an engine cylinder. A piston pin connects the piston to an upper link, which is connected to a lower link by an upper link pin. A crank pin of the crankshaft rotatably supports the lower link thereon. A control link pin connects the lower link to one end of a control link, which is connected at another end to the engine block body by a control shaft. The crank pin has a center arranged on a straight line joining centers of the upper link pin and the control link pin such that an angle formed between the straight line and a horizontal axis that is perpendicular to a center axis of the cylinder and that passes through an axial center of a crank journal is the same for at top dead center and at bottom dead center.

Abstract: A multi-link engine has a piston coupled to a crankshaft to move inside an engine cylinder. A piston pin connects the piston to an upper link, which is connected to a lower link by an upper link pin. A crank pin of the crankshaft rotatably supports the lower link thereon. A control link pin connects the lower link to one end of a control link, which is connected at another end to the engine block body by a control shaft. The upper link has an upper link axis that forms an angle with the cylinder axis, as viewed along a crank axis direction of the crankshaft, such that the angle reaches a minimum when a crank angle of the engine is within a range where the bottom end of a piston skirt is positioned below a topmost part of the bottom end of the cylinder liner.

Abstract: A multi-link engine has a piston that moves inside a cylinder. A piston pin connects the piston to an upper link, which is connected to a lower link. A crank pin of a crankshaft supports the lower link thereon. The lower link is pivotally connected to one end of a control link, which is connected at another end to the engine block body by a control shaft. The control shaft is lower than a crank journal of the crankshaft, and disposed on a first side of a plane that is parallel to a cylinder center axis and that contains a center rotational axis of the crank journal. The cylinder center axis is located on a second (i.e., opposite the first side) plane. The control link has a center axis that is parallel to the cylinder center axis when the piston is near top and bottom dead centers.

Abstract: An in-cylinder direct fuel injection engine is disclosed. The engine comprises a fuel injection valve engaged in a fuel injection hole, a cylinder head, and an ignition plug engaged in an ignition hole, The fuel injection valve is attached to the fuel rail and the fuel injection nozzle injects fuel from the fuel rail. The fuel injection hole and the ignition hole are positioned in a central portion of the a roof of the cylinder head so as to be located between an intake and exhaust air ports and are generally aligned along an axis of a crank shaft.

Abstract: A variable expansion-ratio engine includes an expansion-ratio adjuster configured to adjust an expansion ratio; a load detector configured to detect an engine load; and a controller configured to control the expansion-ratio adjuster. The controller controls the expansion ratio such that the expansion ratio at the time when the load is below a predetermined load value is set lower than that at the time when the load is equal to the predetermined load value.

Abstract: A NOx emission reduction apparatus includes high-temperature EGR gas supply means for supplying a high-temperature EGR gas into an engine cylinder, low-temperature EGR gas supply means for supplying a low-temperature EGR gas into the engine cylinder and very-low-load operation control means for, as an engine load decreases in a very-low-load range, increasing an EGR rate of the high-temperature EGR gas and decreasing an EGR rate of the low-temperature EGR gas for stable engine operations and NOx emission reduction.

Abstract: A NOx emission reduction apparatus includes high-temperature EGR gas supply means for supplying a high-temperature EGR gas into an engine cylinder, low-temperature EGR gas supply means for supplying a low-temperature EGR gas into the engine cylinder and very-low-load operation control means for, as an engine load decreases in a very-low-load range, increasing an EGR rate of the high-temperature EGR gas and decreasing an EGR rate of the low-temperature EGR gas for stable engine operations and NOx emission reduction.

Abstract: A variable expansion-ratio engine includes an expansion-ratio adjuster configured to adjust an expansion ratio; a load detector configured to detect an engine load; and a controller configured to control the expansion-ratio adjuster. The controller controls the expansion ratio such that the expansion ratio at the time when the load is below a predetermined load value is set lower than that at the time when the load is equal to the predetermined load value.

Abstract: A direct-injection internal combustion engine and a combustion method therefore in which fuel injection timing of a fuel injection valve is so configured that (a) the fuel inverted from a cavity in a crown portion of a piston reaches proximity to the discharge electrode portion of a spark plug later than the time of ignition or (b) fuel injection by the fuel injection valve is completed at approximately the same time of ignition. There is no risk of rich combustion at the discharge electrode portion due to the mixed fuel-air mass having a high fuel density, and consequently problems such as wear on the spark plug or smoke generation can be avoided.

Abstract: An in-cylinder direct fuel injection engine is disclosed. The engine comprises a fuel injection valve engaged in a fuel injection hole, a cylinder head, and an ignition plug engaged in an ignition hole, The fuel injection valve is attached to the fuel rail and the fuel injection nozzle injects fuel from the fuel rail. The fuel injection hole and the ignition hole are positioned in a central portion of the a roof of the cylinder head so as to be located between an intake and exhaust air ports and are generally aligned along an axis of a crank shaft.

Abstract: In a direct injection internal combustion engine, a fuel injection valve and a spark plug of adjacent cylinders are inclined at different angles from each other in directions perpendicular to a cylinder arrangement direction in which the cylinders are arranged. Besides, the fuel injection valve and the spark plug of at least one of the cylinders are inclined at different angles from each other in directions parallel to the cylinder arrangement direction. A cooling channel is provided between the fuel injection valve and the spark plug of the at least one of the cylinders.

Abstract: A direct-injection internal combustion engine and a combustion method therefore in which fuel injection timing of a fuel injection valve is so configured that (a) the fuel inverted from a cavity in a crown portion of a piston reaches proximity to the discharge electrode portion of a spark plug later than the time of ignition or (b) fuel injection by the fuel injection valve is completed at approximately the same time of ignition. There is no risk of rich combustion at the discharge electrode portion due to the mixed fuel-air mass having a high fuel density, and consequently problems such as wear on the spark plug or smoke generation can be avoided.

Abstract: A direct fuel injection engine has a fuel injection valve that injects fuel toward a cavity formed in a top of a piston, and a spark plug that ignites the fuel-air mixture resulting from the fuel injection. The direct fuel injection engine is configured to strengthen the penetration of the fuel streams, to improve the directionality of the fuel streams and to form in the cavity an agglomerate fuel-air mixture that is homogeneous and has uniform concentration. The cavity preferably has a bottom surface, a curved surface, and a flat surface. The fuel injection valve has a plurality of injection vents that spray solid-core fuel streams with angles formed between adjacent injection vents that are less than or equal to the spray angle of the fuel stream sprayed from each injection vent. The fuel streams form a combined fuel stream having a hollow circular cone shape.

Abstract: A direct fuel injection internal combustion engine includes a fuel injector arranged above a center portion of the piston and positioned higher than a combustion chamber upper surface of a cylinder head. The cylinder head includes a recess portion in which a tip of the fuel injector is disposed in a cross sectional view of the cylinder head in a plane perpendicular to a fuel injection center axis. The recess portion is provided with a channel extending longitudinally away from the tip of the fuel injector configured and arranged to reduce negative pressure within the recess portion. The channel is oriented in such a direction as to avoid the interference between the channel and other parts of the cylinder head. When the fuel injector is a multi-hole fuel injector, the channel can be oriented toward a direction along a centerline between two adjacent injection vents of the fuel injector.

Abstract: An exhaust emission control apparatus for an internal combustion engine includes a fuel injection valve placed substantially at a midpoint above a combustion chamber of the engine; a piston having an outer cavity formed substantially in a midsection of an upper surface of the piston and an inner cavity formed in a bottom surface of the outer cavity; an ignition plug placed in a region right above the outer cavity; an exhaust purifying catalyst provided in an exhaust passage of the engine; and a controller. This controller is configured to carry out a stratified charge combustion when a temperature rise for the exhaust purifying catalyst is required, by forming air-fuel mixture which is richer than stoichiometric ratio and is able to be ignited by the ignition plug, within the outer cavity and in an area substantially right above the outer cavity, from a fuel injected through the fuel injection valve.