An internal combustion engine includes: a piston guided by a cylinder to reciprocate along a cylinder axis and forming a combustion chamber with a crown surface facing a cylinder head; and a fuel injection valve having an injection port facing the combustion chamber and injecting fuel to a forward tumble flow in the combustion chamber. A ridge formed on the crown surface rises toward a ceiling surface side relative to a reference plane, orthogonal to the cylinder axis and including an outer peripheral edge of the crown surface, and has a ridge line formed by a curved surface to surround a recessed part. The recessed part is recessed toward a center of the crown surface in a direction orthogonal to a virtual plane including the cylinder axis and parallel to a rotation axis of a crankshaft, and is recessed toward the center in an axial direction of the crankshaft.

A method of controlling an engine is provided, the method including the steps of injecting main fuel by a fuel injector during an intake stroke or a compression stroke, providing a mixture gas containing fuel and air inside a cylinder, applying by an ignition device a high voltage between electrodes of a spark plug at a timing when the mixture gas is not ignited, detecting a parameter related to a current value of an electric-discharge channel generated between the electrodes, determining whether the detected parameter is within a range between a first threshold and a second threshold to determine a flowing state of a vortex inside the cylinder, injecting supplemental fuel by the fuel injector after the main fuel injection when the parameter is determined to be outside the range, and igniting the mixture gas by the ignition device using the spark plug after the supplemental fuel injection.

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).

A structure of a combustion chamber for an engine includes a crown surface of a piston, a combustion chamber ceiling surface, an injector and an ignition plug provided on the combustion chamber ceiling surface, and an intake opening and an exhaust opening opened in the combustion chamber ceiling surface. A side where the intake opening is opened is defined as an intake port side, and a side where the exhaust opening is opened is defined as an exhaust port side. An ignition portion of the ignition plug is disposed on the intake port side. The ignition plug is ignited at a timing after the piston passes a compression top dead center. The injector is disposed on the center portion, and is configured to inject fuel toward the exhaust port side. A cavity is provided on the crown surface. A reverse squish flow generation portion is provided in the combustion chamber.

A weak tumble flow fast combustion system is provided. An intake throat and an exhaust throat are provided on a cylinder head, a section of an intake duct close to the intake throat is a tumble guide duct, an axis of the tumble guide duct is arranged obliquely with respect to the bottom surface of the cylinder head, and an upper side surface of the tumble guide duct is a flowing-down guide surface arranged obliquely with respect to the bottom surface of the cylinder head, a lower side surface of the tumble guide duct is an arc-shaped guide surface recessed toward the bottom surface of the cylinder head, an eccentric chamfer is provided at the lower end of the intake throat, and the eccentric direction of the eccentric chamfer is offset along the direction connecting the center of the intake throat to the exhaust throat.

A fuel injection control device for an engine is provided. A swirl generator generates a swirl flow inside a combustion chamber. A fuel injector with multiple nozzle holes injects fuel into the combustion chamber, and forms a lean mixture gas inside the combustion chamber. An spark plug ignites the lean mixture gas to cause a portion of the mixture gas to start combustion accompanied by flame propagation, and then combusts by self-ignition. The fuel injector has first and second nozzle holes, and a first atomized fuel spray injected from the first nozzle hole and a second atomized fuel spray injected from the second nozzle hole separate from each other by the swirl flow. The fuel injector sequentially performs a first injection and a second injection in an intake stroke. The controller makes an injection amount of the second injection greater than that of the first injection.

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).

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).

An internal combustion engine is provided with a pre-chamber provided inside a main combustion chamber. The pre-chamber includes an ignition plug, and a casing provided to a ceiling part to cover the ignition plug, the casing isolating an internal space formed therein from the main combustion chamber. A tumble flow of a mixture gas is formed inside the main combustion chamber. A plurality of communicating holes are formed in the casing, and include a first communicating hole opening to an intake port side and a second communicating hole opening to an exhaust port side. The tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow. The main combustion chamber is provided with a structure configured to suppress a flow opposing the vortex flowing into the pre-chamber through the second communicating hole.