An exhaust gas recirculation (EGR) passage is connected with an intake passage (a bypass passage bypassing a supercharger) of an engine. The EGR passage includes, in a position close to a connection port to the intake passage, an expanding portion in which a passage cross-sectional area expands and which lowers a flow speed of EGR gas so as to reduce an uneven flow, in the connection port, of the EGR gas flowing into the intake passage.

The invention concerns an internal combustion engine system (2), comprising an internal combustion engine (4) and an exhaust gas recirculation circuit (12, 14, 16, 18, 20, 22) connecting an exhaust manifold (8) of the engine to an intake manifold (6) of the engine, the circuit comprising at least one reed valve (16), an EGR valve (22), that is arranged downstream of the reed valve on the path of exhaust gas flowing from the exhaust manifold (8) to the intake manifold (6) and an EGR line (18) connecting the reed valve to the EGR valve. The system further includes a bypass line (30) for gas, connecting the EGR line (18) to an exhaust line (10) of the engine and control means (20, 40, 42) for controlling the flow of gas discharged through the bypass line.

The invention concerns an internal combustion engine system (2), comprising an internal combustion engine (4) and an exhaust gas recirculation circuit (12, 14, 16, 18, 20, 22) connecting an exhaust manifold (8) of the engine to an intake manifold (6) of the engine, the circuit comprising at least one reed valve (16), an EGR valve (22), that is arranged downstream of the reed valve on the path of exhaust gas flowing from the exhaust manifold (8) to the intake manifold (6) and an EGR line (18) connecting the reed valve to the EGR valve. The system further includes a bypass line (30) for gas, connecting the EGR line (18) to an exhaust line (10) of the engine and control means (20, 40, 42) for controlling the flow of gas discharged through the bypass line.

An exhaust system with a first and a second exhaust conduit arranged in a parallel flow arrangement. The exhaust system further includes an exhaust gas heat recovery (EGHR) heat exchanger coupled to an exterior of the first exhaust conduit. The exhaust system further includes a first flow control valve controlling the flow of exhaust gas into the EGHR heat exchanger from the first exhaust conduit and a second flow control valve controlling the flow of exhaust gas through the second exhaust conduit.

An exhaust system with a first and a second exhaust conduit arranged in a parallel flow arrangement. The exhaust system further includes an exhaust gas heat recovery (EGHR) heat exchanger coupled to an exterior of the first exhaust conduit. The exhaust system further includes a first flow control valve controlling the flow of exhaust gas into the EGHR heat exchanger from the first exhaust conduit and a second flow control valve controlling the flow of exhaust gas through the second exhaust conduit.

An internal combustion engine includes a supercharger having a compressor and a turbine and an EGR apparatus having an exhaust recirculating pipe, an upstream EGR valve and a downstream EGR valve. An electronic control unit fully opens the upstream EGR valve and controls an EGR amount by the downstream EGR valve when a peak value of an exhaust pressure increases excessively. The resulting increase in exhaust volume causes the peak value of the exhaust pressure to fall, and damage to parts of an exhaust system can be avoided. The electronic control unit fully opens the downstream EGR valve and controls the EGR amount by the upstream EGR valve when the peak value of the exhaust pressure decreases excessively. The resulting decrease in the exhaust volume causes the peak value of the exhaust pressure to rise, enabling supercharging.

An internal combustion engine includes a supercharger having a compressor and a turbine and an EGR apparatus having an exhaust recirculating pipe, an upstream EGR valve and a downstream EGR valve. An electronic control unit fully opens the upstream EGR valve and controls an EGR amount by the downstream EGR valve when a peak value of an exhaust pressure increases excessively. The resulting increase in exhaust volume causes the peak value of the exhaust pressure to fall, and damage to parts of an exhaust system can be avoided. The electronic control unit fully opens the downstream EGR valve and controls the EGR amount by the upstream EGR valve when the peak value of the exhaust pressure decreases excessively. The resulting decrease in the exhaust volume causes the peak value of the exhaust pressure to rise, enabling supercharging.

An engine system includes an engine including a plurality of engine cylinders, an intake manifold, and an exhaust manifold; and a compound turbocharger system having a first turbine driving a first compressor, and a second turbine driving a second compressor. The engine system further includes an intake line including the first compressor, the second compressor, and the at least one intake manifold; and an exhaust line including the exhaust manifold, the second turbine, and the first turbine. The engine system also includes an exhaust restriction valve located in the exhaust manifold of the engine downstream of a subset of the plurality of the engine cylinders; and an exhaust gas recirculation line having an upstream end located to receive exhaust from the subset of the plurality of engine cylinders, and a downstream end coupled to the intake line downstream the first compressor and upstream of the second compressor.

An engine system includes an engine including a plurality of engine cylinders, an intake manifold, and an exhaust manifold; and a compound turbocharger system having a first turbine driving a first compressor, and a second turbine driving a second compressor. The engine system further includes an intake line including the first compressor, the second compressor, and the at least one intake manifold; and an exhaust line including the exhaust manifold, the second turbine, and the first turbine. The engine system also includes an exhaust restriction valve located in the exhaust manifold of the engine downstream of a subset of the plurality of the engine cylinders; and an exhaust gas recirculation line having an upstream end located to receive exhaust from the subset of the plurality of engine cylinders, and a downstream end coupled to the intake line downstream the first compressor and upstream of the second compressor.

A dedicated exhaust gas recirculation configuration that provides reduced exhaust gas recirculation (EGR) backflow and reduced fresh air backflow. One-way valves are positioned in the EGR loop to reduce or avoid fresh-air backflow into the dedicated exhaust gas recirculating cylinder and/or positioned in the engine intake passage to reduce or avoid dedicated cylinder exhaust gas backflow into the intake passage.