A combustion chamber structure for an internal combustion engine includes a recessed portion formed in a pent roof of a cylinder head on an upstream side of a tumble flow with respect to a spark plug.

The present invention relates to a gas inlet device (1) for a cylinder of an internal combustion engine. The gas inlet device (1) comprises an inlet port (5), an inlet valve (4), a calibration (6) of the inlet valve (4), means for forming a tumble-type aerodynamic movement of the gas in the cylinder, and a mask (10). Furthermore, the intersection (7) between the inlet port (5) and the calibration (6) is along a straight line not parallel to the plane of the firing face (FF). In addition, the mask (10) is oriented in the same way as the end of the inlet port (5).

The present invention relates to a gas intake pipe (2) for a cylinder of a thermal engine. The pipe comprises means for diverting the gas so as to generate a tumble type aerodynamic motion of the gas within the cylinder. The diversion means comprise at least a “ramp” shape (6) on the lower profile (12) of the pipe and a concave zone on the upper profile (10) of intake pipe (2).

The present invention relates to a gas intake pipe (2) for a cylinder of a thermal engine. The pipe comprises means for diverting the gas so as to generate a tumble type aerodynamic motion of the gas within the cylinder. The diversion means comprise at least a “ramp” shape (6) on the lower profile (12) of the pipe and a concave zone on the upper profile (10) of intake pipe (2).

The present invention relates to a gas intake device (1) for a cylinder of an internal-combustion engine. Gas intake device (1) comprises an intake pipe (2), an intake valve (3), a calibration part (4) for intake valve (3), and means for generating an aerodynamic motion of the gas in the cylinder about an axis substantially perpendicular to the axis of said cylinder. Furthermore, intersection (7) between intake pipe (2) and calibration part (4) occurs in a line nonparallel to the plane of fire face (FF).

A compression ignited combustion engine has at least one cylinder and first and second gas intake ports in a cylinder head restricting a combustion chamber. One gas intake passage leads to the two ports and is widened in a Y-shaped end influencing gas entering each port into a tangential flow in opposite direction with respect to the flow into the other port. The first intake port is designed to allow gas entering this port to continue said tangential flow so as to enter the combustion chamber in a swirl in a first rotation direction, whereas the second intake port is designed to guide gas entering this port to also enter the combustion chamber in a swirl in said first rotation direction.

Embodiments of apparatus are disclosed for affecting working fluid flow in a system that delivers material between two locations by carrying the material in the working fluid. For example, embodiments of the disclosed apparatus may be used in an internal combustion engines to carry fuel droplets to a combustion area using air as the working fluid. The apparatus may include a passage including a funnel portion and tumble area that direct working fluid into a stratified stream. The stratified stream may include an outer boundary flow having a toroidal and/or helical flow characteristic and an inner flow carrying injected material that is bound by the outer flow.

The present invention relates to a gas intake device (1) for a cylinder of an internal-combustion engine. Gas intake device (1) comprises an intake pipe (2), an intake valve (3), a calibration part (4) for intake valve (3), and means for generating an aerodynamic motion of the gas in the cylinder about an axis substantially perpendicular to the axis of said cylinder. Furthermore, intersection (7) between intake pipe (2) and calibration part (4) occurs in a line nonparallel to the plane of fire face (FF).

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug. The cavity includes a bottom surface and a tubular peripheral surface, and is formed in such a way that a ratio of a depth of the cavity with respect to a diameter of the cavity is 0.3 or smaller.

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug, the intake-side inclined surface and the exhaust-side inclined surface are formed in such a way that an inclination angle of the exhaust-side inclined surface is smaller than an inclination angle of the intake-side inclined surface, and a difference in inclination angle between the intake-side inclined surface and the exhaust-side inclined surface is 4 degrees or larger.