Abstract: There is provided a method of controlling a spark ignited internal combustion engine having a fuel injector which injects fuel directly into its combustion chamber. The method comprises injecting a total amount of fuel into a combustion chamber by early in a compression stroke during a cylinder cycle at a first engine speed. The method further comprises injecting a first stage of fuel into the combustion chamber during a cylinder cycle by an early in a compression stroke of the cylinder cycle, and injecting a second stage of fuel by late in the compression stroke during the cylinder cycle at a second engine speed less than the first engine speed, after injecting the first stage of fuel. The amount of the second stage fuel is greater than an amount of said first stage fuel. Accordingly, the first and second stage fuels may not be pre-ignited before the spark ignition.

Abstract: A multi-hole injector directly injects fuel into a combustion chamber. Intake air is introduced into the combustion chamber through intake ports to provide tumble flow in the combustion chamber. A cavity is formed in a part of the top surface of a piston which is eccentric to the exhaust side. In the intake stroke, fuel injection ends in a downstroke of a piston. When the crank angle is 100 degrees after the top dead center in the intake stroke at which the fuel injection ends, a most downward lower spray collides with a part of the top surface of the piston which ranges on the intake side from the edge on the exhaust side of the cavity. A most upward upper spray does not come into contact with a spark plug. Thus, the fuel injection can enhance the tumble flow to promote homogeneous dispersion of fuel-air mixture in the combustion chamber.

Abstract: A system and method of controlling an internal combustion engine are provided. The method may include closing said intake valve at a timing in a first range, which is before a maximum charge closing timing with which an amount of air inducted into said cylinder from said air intake passage would be maximized at a given engine speed, during a cylinder cycle when a desired amount of air to be inducted into said cylinder is less than or equal to a predetermined air amount at the given engine speed. The method may further include closing said intake valve at a timing in a second range, which is after said maximum charge closing timing and separated from said first range during a cylinder cycle, when a desired amount of air to be inducted into said cylinder is greater than said predetermined air amount at the given engine speed.

Abstract: Methods and systems for controlling an internal combustion engine are provided. One example method may include closing an intake valve later during a cylinder cycle than a timing with which an amount of air inducted into a cylinder from an air intake passage would be maximized, and earlier during the cylinder cycle as a desired amount of air to be inducted into the cylinder increases, while an engine is operating at a given engine speed. The method may further include closing the intake valve earlier during a cylinder cycle as the engine speed increases when the desired amount of air to be inducted into the cylinder is at a maximum.

Abstract: This invention relates to a combustion chamber structure for a spark-ignition engine, which comprises a combustion chamber defined between a bottom surface of a cylinder head and a top surface of a piston in such a manner that the bottom surface of the cylinder head serves as a ceiling wall thereof, and a spark plug having a sparking end protruding from the ceiling wall into the combustion chamber. In this combustion chamber structure, when the piston is at a top dead center, a principal space of the combustion chamber is comprised of a first combustion space around the sparking end of the spark plug and a second combustion space around a circumference of a cylinder bore. Further, the first combustion space and the second combustion space are communicated with each other through a small interspace zone where an interspace between the ceiling wall and the top surface of the piston is narrowed. The combustion chamber structure makes it possible to increase compression ratio in a practically effective manner.

Abstract: This invention relates to a combustion chamber structure for a spark-ignition engine, which comprises a combustion chamber defined between a bottom surface of a cylinder head and a top surface of a piston in such a manner that the bottom surface of the cylinder head serves as a ceiling wall thereof, and a spark plug having a sparking end protruding from the ceiling wall into the combustion chamber. In this combustion chamber structure, when the piston is at a top dead center, a principal space of the combustion chamber is comprised of a first combustion space around the sparking end of the spark plug and a second combustion space around a circumference of a cylinder bore. Further, the first combustion space and the second combustion space are communicated with each other through a small interspace zone where an interspace between the ceiling wall and the top surface of the piston is narrowed. The combustion chamber structure makes it possible to increase compression ratio in a practically effective manner.