A structure of a combustion chamber for an engine includes: a crown surface of a piston; a combustion chamber ceiling surface formed on a cylinder head; and an ignition plug mounted on the combustion chamber ceiling surface, and including an ignition portion disposed in such a way as to face the combustion chamber. The crown surface of the piston includes a cavity which is recessed in a cylinder axis direction in a region including a position below the ignition portion of the ignition plug in a plan view from the cylinder axis direction. A rim portion of the cavity includes a guide portion, raised in the cylinder axis direction with respect to an inner region of the rim portion, interposing the ignition portion when the piston is at a compression top dead center, and configured to guide an air-fuel mixture within the combustion chamber to the ignition portion.

A fuel injection control device for an engine is provided. A fuel injector with multiple nozzle holes forms a lean mixture gas inside a combustion chamber, a spark plug ignites to cause the mixture gas to start combustion accompanied by flame propagation, then combust by self-ignition. A first atomized fuel spray injected from a first nozzle hole and a second atomized fuel spray injected from a second nozzle hole separate from each other by a swirl flow, and a third atomized fuel spray injected from a third nozzle hole and a fourth atomized fuel spray from a fourth nozzle hole approach each other by the swirl flow so that a first area and a second area where mixture gas is richer are formed inside the combustion chamber. The fuel injector sequentially performs first, second, and third injections with an injection interval therebetween in an intake stroke.

Methods and systems are provided for a pre-chamber. In one example, a pre-chamber comprises a plurality of slots fluidly coupling it to a primary combustion chamber. The plurality of slots comprising a plurality of corresponding flaps configured to direct gases through the plurality of slots.

In an internal combustion engine provided with an electro-hydraulic system for variable actuation of the intake valves of the engine, each cylinder has two intake valves, which are associated with two intake conduits and are controlled by a single cam of a camshaft through a single hydraulic circuit. The communication of the hydraulic actuators of the two intake valves with a discharge channel is controlled by two electrically-actuated control valves, both of an on/off two-position type, arranged in series with each other along a hydraulic line for communication between the a pressure volume and the discharge channel.

A combustion chamber structure for an engine includes a combustion chamber where SI combustion by spark ignition and CI combustion by self-ignition are conducted. A crown surface includes a cavity recessed to have a bowl-shape; a pair of first raised portions having a mound-shape along a pent roof shape; and a second raised portion provided to protrude at a position orthogonal to a ridge extending direction of the pair of first raised portions. With a height of the first raised portion relative to a height position of a deepest portion of the cavity being represented as H1 and a height of the second raised portion being represented as H2, H1/H2 as a ratio of the height H1 of the first raised portion to the height H2 of the second raised portion is set to be in a range of 1.92 or more and 2.75 or less.

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.

An overhead cam engine system comprises a rotating overhead exhaust cam rail comprising a plurality of exhaust lobes. A first switching roller finger follower actuates a first exhaust valve, and is configured to switch between a first lift profile and a second lift profile. A second switching roller finger follower is coupled to actuate a second exhaust valve, and is configured to switch between a third lift profile and a fourth lift profile. The third and fourth lift profile are different than the first and second lift profile. An actuation assembly is connected to switch the first switching roller finger follower and the second switching roller finger follower to select between at least three exhaust lift modes to open and close the first exhaust valve and the second exhaust valve using combinations of the first, second, third and fourth lift profiles.

A control device of an engine including a cylinder, a piston, a cylinder head, and a combustion chamber is provided, which includes intake and exhaust ports, a swirl control valve provided in an intake passage connected to the intake port, a fuel injection valve attached to the cylinder head to be oriented into the center of the combustion chamber in a plan view thereof, and having first and second nozzle ports, and a control unit. The control unit includes a processor configured to execute a swirl opening controlling module to output the control signal to the swirl control valve to have a given opening at which a swirl ratio inside the combustion chamber becomes 2 or above, and a fuel injection timing controlling module to output the control signal to the fuel injector to inject fuel at a given timing at which the swirl ratio becomes 2 or above.

A boosted engine is provided, which includes an engine body formed with a combustion chamber, a spark plug, a fuel injection valve, a booster, a boost controller, and a control unit including an operating range determining module and a compression end temperature estimating module. In a high load range, the fuel injection valve and the spark plug are controlled so that a mixture gas inside the combustion chamber starts combustion through flame propagation by ignition of the spark plug, and unburned mixture gas then combusts by compression ignition, and the boost controller is controlled to bring the booster into a boosting state. When a gas temperature inside the combustion chamber exceeds a given temperature at CTDC, the fuel injection valve is controlled so that a fuel injection end timing occurs on a compression stroke, and the spark plug is controlled so that the mixture gas is ignited after CTDC.

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.