Methods and systems are provided for merging recirculated exhaust gas (EGR) with fresh intake air in an intake passage. In one example, a method may include introducing EGR to the intake passage via an angled annular slot and flowing unmixed EGR and ambient air through an intake compressor inlet. Ambient air may flow to a center of the intake compressor while the EGR may flow along a periphery of the intake compressor inlet.

Disclosed are two system devices for stratified injecting the recirculated exhaust gas and high-specific-heat-capacity or inert gas for clean combustion of an internal combustion engine. The former is composed of an exhaust gas recirculation system, an injection system, and a power system. The latter is composed of four parts, and a high-specific-heat-capacity gas or inert gas channel is added. Injectors can be arranged at any position in the cylinder between a top dead center and a bottom dead center of a piston in a cylinder; 1-3 layers of injectors can be arranged; and 2-6 injectors can be arranged on each layer. Gas participating in combustion enters the cylinder from two intake channels, namely, a scavenging port of the internal combustion engine and the injectors; an in-cylinder swirl ratio can be remarkably increased through kinetic energy carried by the gas; and fuel-gas mixing is promoted, and the combustion rate is increased.

Disclosed are two system devices for stratified injecting the recirculated exhaust gas and high-specific-heat-capacity or inert gas for clean combustion of an internal combustion engine. The former is composed of an exhaust gas recirculation system, an injection system, and a power system. The latter is composed of four parts, and a high-specific-heat-capacity gas or inert gas channel is added. Injectors can be arranged at any position in the cylinder between a top dead center and a bottom dead center of a piston in a cylinder; 1-3 layers of injectors can be arranged; and 2-6 injectors can be arranged on each layer. Gas participating in combustion enters the cylinder from two intake channels, namely, a scavenging port of the internal combustion engine and the injectors; an in-cylinder swirl ratio can be remarkably increased through kinetic energy carried by the gas; and fuel-gas mixing is promoted, and the combustion rate is increased.

Embodiments for inducing swirl upstream of a compressor are provided. In one example, a method includes during a first condition, flowing exhaust gas from downstream of a turbine to upstream of a compressor via a tangential flow duct of an exhaust gas recirculation (EGR) injector circumferentially surrounding an intake passage upstream of the compressor, and during a second condition, flowing exhaust gas from downstream of the turbine to upstream of the compressor via a radial flow duct of the EGR injector.

Embodiments for inducing swirl upstream of a compressor are provided. In one example, a method includes during a first condition, flowing exhaust gas from downstream of a turbine to upstream of a compressor via a tangential flow duct of an exhaust gas recirculation (EGR) injector circumferentially surrounding an intake passage upstream of the compressor, and during a second condition, flowing exhaust gas from downstream of the turbine to upstream of the compressor via a radial flow duct of the EGR injector.

To solve the problems of compressor wheel blade flow separation causing surge type noises when an exhaust gas recirculation (EGR) duct introduces into the compressor exhaust gases to be returned to the engine, the exhaust gas is fed into an annular volume, defined between inner and outer walls or an annular transition cavity shaped as a radially expanded, axially flattened cylindrical space in the compressor inlet, so that the generally unidirectional radial flow from an EGR duct is re-directed and organized as it is turned from generally radial to generally axial, merging with the general inlet flow and presenting the compressor wheel with airflow of “circumferentially uniform” flow velocity.

To solve the problems of compressor wheel blade flow separation causing surge type noises when an exhaust gas recirculation (EGR) duct introduces into the compressor exhaust gases to be returned to the engine, the exhaust gas is fed into an annular volume, defined between inner and outer walls or an annular transition cavity shaped as a radially expanded, axially flattened cylindrical space in the compressor inlet, so that the generally unidirectional radial flow from an EGR duct is re-directed and organized as it is turned from generally radial to generally axial, merging with the general inlet flow and presenting the compressor wheel with airflow of “circumferentially uniform” flow velocity.

The invention relates to a device for mixing a stream of supercharging air and a stream of recirculated exhaust gases. The device comprises a manifold allowing the stream of air and the stream of recirculated gases to be mixed, and allowing the mixture to be distributed in the cylinder head. The device also comprises means for conveying the recirculated exhaust gases in the manifold that allow the distributed injection of the recirculated exhaust gases into the stream of supercharging air. The device additionally comprises means for thermally insulating the conveying means in order to limit the cooling of the recirculated exhaust gases by the supercharging air.

The invention relates to a device for mixing a stream of supercharging air and a stream of recirculated exhaust gases. The device comprises a manifold allowing the stream of air and the stream of recirculated gases to be mixed, and allowing the mixture to be distributed in the cylinder head. The device also comprises means for conveying the recirculated exhaust gases in the manifold that allow the distributed injection of the recirculated exhaust gases into the stream of supercharging air. The device additionally comprises means for thermally insulating the conveying means in order to limit the cooling of the recirculated exhaust gases by the supercharging air.

The invention concerns a discharge valve (17) intended to be fitted in a discharge duct of an apparatus designed to be driven by a fluid, in particular a turbocharger driven by the exhaust gases from an engine. The discharge valve (17) comprises a cavity (83) having a first (85), a second (87) and a third aperture (89), each intended to be connected to a respective duct, the discharge valve (17) also comprising first (91) and second (93) means for closing the first (85) and second (87) apertures, respectively, in order to control communication between the ducts.