An inlet duct, an induction system, and a system are disclosed for directing an inlet flow into an inlet compressor for use in an internal combustion engine. An example inlet duct may include one or more relief features disposed on an inner surface of the inlet duct. The one or more relief features may be made integral with the inlet duct. The one or more relief features may be disposed to protrude into the inlet flow to cause the inlet flow to swirl before reaching the inlet compressor.

An object is to position a plurality of guide vanes for generating swirl flow at a housing inner circumferential side in front of an impeller wheel to improve a surge margin and to restrict the decrease in a choke flow rate, thereby increasing an operation range of a compressor. A compressor 19 includes a compressor housing 15, an impeller wheel 7 which compresses intake gas flowing in from an intake-air inlet 23, a swirl-flow generating part including a plurality of guide vanes 55 disposed circumferentially along an inner circumferential wall of the intake-air channel 21 between the intake-air inlet 23 and the impeller wheel 7 and which swirls the intake gas from the intake-air inlet 23 around the rotational axis, and a central intake-air flow path 59 formed inside the guide vanes 55 to allow intake gas to flow to the impeller wheel 7 without passing through the guide vanes 55.

The subject matter of this specification can be embodied in, among other things, a gas mixer that includes a convergent-divergent nozzle comprising a convergent portion and a divergent portion and defining a first gas flow path, an air housing comprising an air inlet configured to supply air to the first gas flow path upstream of the convergent-divergent nozzle, a gas housing defining a second gas flow path and including a first gas inlet configured to receive a secondary gas and allow the secondary gas into a second gas flow path, and a gas nozzle positioned parallel to and centrally within the first gas flow path in a convergent portion of the convergent-divergent nozzle, the gas nozzle configured to supply the secondary gas to the first gas flow path upstream of the divergent portion.

Various methods and systems are provided for an intake manifold for an engine. In one example, an insert comprises an annular body having a top surface, bottom surface, inner surface, and outer surface. The insert further comprises a first groove for coupling an intake air port of an intake manifold to a cylinder head, a second groove for circulating gaseous fuel received from a gas runner of the intake manifold, and one or more openings to fluidically couple the second groove to an interior of the intake air port. The insert is configured to mix gaseous fuel and intake air at a coupling location between the intake manifold and the cylinder head.

An intake noise reduction device that can mitigate deformation of a flow-regulating net portion made of an elastic body. The intake noise reduction device 100 is made of an elastic body that is disposed downstream of a throttle valve and includes an annular gasket portion 110 and a flow-regulating net portion 120 provided inside the gasket portion 110 integrally with the gasket portion 110, constituted by a linear portion having a mesh shape. The linear portion having the mesh shape constituting the flow-regulating net portion 120 includes first linear parts 121 that extend radially and second linear parts 122 that extend circumferentially. One of any given two parts of the first linear part 121 on a radially outer side has a width larger than or equal to that of the other part on a radially inner side, and a radially outermost part of the first linear part has a larger width than a radially innermost part.

An air pre-cleaner spin tube includes a vaned inlet section including an inlet flange, and an outer tube inlet portion including an outer wall forming a nozzle that defines a radial direction, and a longitudinal axis. Also, a central stem is disposed in the nozzle, and a plurality of vanes extends from the central stem to the outer wall.

An apparatus and methods are provided for a throttle body spacer that improves the performance of an internal combustion engine. The throttle body spacer comprises a body that includes an airflow opening for conducting airflow from a throttle body into an intake manifold. A spiral is disposed along a sidewall of the airflow opening and configured for swirling the airflow. The spiral comprises a helical shape disposed around a circumference of the sidewall and extends from an initial bore near a first contact surface of the body to a second contact surface. The helical shape includes a diameter that increases as the spiral extends toward the second contact surface, giving the body a sidewall taper angle that contributes to an increase in power output of the engine. A sawtooth cross-sectional shape of the spiral causes the airflow to swirl so as to improve atomization of an air-fuel mixture entering engine.

An engine system is provided, which includes an engine, a swirl control valve, and a controller. The engine includes a cylinder, a piston, and a fuel injection valve provided incliningly with respect to an axial direction of the piston and configured to directly inject fuel into the cylinder. The swirl control valve is provided inside an intake passage and generates a swirl flow inside the cylinder at least when the valve closes. When an engine load is below a given threshold, the controller controls the swirl control valve to close, and controls the fuel injection valve to inject fuel during an intake stroke. While the engine load is below the threshold, at a fixed engine speed, the controller controls to advance a fuel injection timing when the engine load is at a first load, compared with at a second load higher than the first load.

An exhaust gas recirculation system for an engine includes a conduit, and a U-shaped exhaust gas mixer. The conduit is configured to direct an exhaust gas away from an exhaust manifold. The U-shaped exhaust gas mixer is configured to direct exhaust gas from the conduit and into an engine air intake system. The U-shaped exhaust gas mixer is arranged with a pre-mixing cavity configured to disperse the exhaust gas and entraining the exhaust gas into an intake air flow prior to distribution into an intake manifold of an engine.

The present disclosure provides an apparatus for improving engine air flow including: a combination recess which is formed at an intake port of a cylinder head and is extended toward a combustion chamber along an air flow path at a position combined with an intake manifold; a fixing body which is fit-inserted to and combined to the combination recess; and a plate an end of which is combined to the fixing body on the flow path of the intake port and which guides the air flow flowing into the intake port.