A fuel injector includes a nozzle body having spray orifices formed therein each defining a spray orifice diameter dimension (d), and a plurality of spray ducts each in spray path alignment with one of the plurality of spray orifices and including a duct outlet defining a duct exit diameter dimension (D). Each of the spray ducts defines, together with the respective one of the spray orifices, a relative spray area reduction (SAR) at the duct outlet. The ratio of D/d is at least 14, and the SAR is 80% or greater. The configuration provides reduced soot production. Related methodology is disclosed.

A valve with an opening is driven by an electric motor to rotate around the cylinder of an opposed piston engine such that the opening separately matches an intake and exhaust opening on the cylinder to allow fuel to enter the combustion chamber of the engine and allow exhaust to be expelled. The intake and exhaust cylinder openings may be separated from each other by approximately sixty degrees of the outside of the cylinder.

A fuel system for an internal combustion engine includes a fuel injector having a nozzle with first and second sets of spray orifices formed therein. The fuel injector also includes a first and a second outlet check movable to open and close the first and second sets of spray orifices. Spray plume ducts are supported at fixed orientations relative to a nozzle of the fuel injector, and each are oriented in-line with a center axis defined by one of the spray orifices. The spray plume ducts may be directly attached to the fuel injector or to a duct carrier mounted to an engine head.

A control system for a pre-mixture compression-ignition engine is provided, configured such that in a first combustion mode, the control unit controls the fuel injection valve to have a fuel amount within a mixture gas in an outer circumferential portion of the combustion chamber larger than in the center portion, the swirl generating part to generate a swirl flow in the outer circumferential portion, and the spark plug to ignite the mixture gas in the center portion. In a second combustion mode, the control unit controls the fuel injection valve to start a fuel injection on intake stroke so that the mixture gas is formed in the entire combustion chamber, the swirl generating part so that a swirl flow becomes weaker than in the first combustion mode, and the spark plug to ignite the mixture gas before CTDC.

A piston for an internal combustion engine, such as a high-pressure direct injection (HPDI) diesel/gas internal combustion engine. The piston has a piston recess, in particular an omega piston recess. The piston has a piston crown face which is provided so as to extend annularly about a centre axis (M) of the piston. The piston has a plurality of piston stages, which are provided so as to extend annularly about the centre axis (M) and which are arranged between the piston crown face and the piston recess. The piston geometry can lead to an increase of the degree of engine efficiency with a simultaneous reduction of the exhaust emissions.

A piston for an internal combustion engine, such as a high-pressure direct injection (HPDI) diesel/gas internal combustion engine. The piston has a piston recess, in particular an omega piston recess. The piston has a piston crown face which is provided so as to extend annularly about a centre axis (M) of the piston. The piston has a plurality of piston stages, which are provided so as to extend annularly about the centre axis (M) and which are arranged between the piston crown face and the piston recess. The piston geometry can lead to an increase of the degree of engine efficiency with a simultaneous reduction of the exhaust emissions.

The fuel injection timing IT is changed based operation and environmental condition of the engine. If the injection timing IT is changed, the rate of fuel passing through meshes of the mesh member (i.e., the mesh passing rate) changes. If the mesh passing rate changes, the set-off position (i.e., the ignition position of the air-fuel mixture) is extended or shortened. Based on this, under the condition of high ignition performance (i.e., the second condition), the mesh passing rate is controlled to increase thereby the set-off position is extended. On the other hand, under the condition of low ignition performance (i.e., the first condition), the mesh passing rate is controlled to decrease thereby the extension of the set-off position is suppressed or prohibited.

A piston for an internal combustion engine includes a crown portion having a bowl that includes a plurality of protrusions. Each of the plurality of protrusions includes a first side surface and a second side surface. Other features including at least one ledge formed between protrusions in segments, and a generally flat, inward facing surface on the protrusions may also be used.

Pistons for opposed-piston engines include an interior annular cooling gallery. The gallery is provided with inlet and drain passageways constructed to shield a jet of liquid coolant entering the gallery, thereby reducing interference between the incoming jet and liquid coolant circulating in the gallery.

Pistons for opposed-piston engines include an interior annular cooling gallery. The gallery is provided with inlet and drain passageways constructed to shield a jet of liquid coolant entering the gallery, thereby reducing interference between the incoming jet and liquid coolant circulating in the gallery.