An exhaust heat recovery device according to one aspect of the present disclosure includes a heat exchanger, a supply flow path, and a discharge flow path. The heat exchanger has a plurality of heat exchange flow paths configured to carry out heat exchange between exhaust gas and a heat exchange medium. The supply flow path is configured such that the exhaust gas flows therethrough, and the flowing exhaust gas is supplied to the plurality of heat exchange flow paths while being branched. The discharge flow path is configured to merge and discharge the heat-exchanged exhaust gas having passed through the plurality of heat exchange flow paths. At least one flow path of the supply flow path and the discharge flow path is configured to be narrower toward a downstream side in a flow direction of the exhaust gas.

An exhaust gas recirculation (EGR) system for an internal combustion engine having two dedicated EGR cylinders. A dual valve system is used to control the output of the dedicated EGR cylinders so that the engine may intake EGR exhaust from both, only one, or neither of the dedicated EGR cylinders.

An exhaust gas recirculation (EGR) system for an internal combustion engine having two dedicated EGR cylinders. A dual valve system is used to control the output of the dedicated EGR cylinders so that the engine may intake EGR exhaust from both, only one, or neither of the dedicated EGR cylinders.

An exhaust gas recirculation system is provided for an internal combustion engine having reciprocating piston design with an exhaust gas turbocharger unit having an exhaust gas turbine and a supercharger. The internal combustion engine has a machine housing accommodating one or more cylinders having reciprocating pistons, which is provided with a suction unit and an exhaust gas outlet unit, which is connected to the exhaust gas turbine by way of an exhaust gas line. The exhaust gas line supplies at least a part of the exhaust gas stream to the suction unit via the exhaust gas recirculation system. To optimize the exhaust gas recirculation system, it has a pipe branch, which is connected to the exhaust gas line and is connected to an exhaust gas recirculation line with a control element interconnected. The exhaust gas recirculation line extends, on the one hand, with a first supply line section outside and, on the other hand, with a second supply line section in an interior of, a suction unit container of the suction unit. An exhaust gas stream is conveyed by the second supply line section into the suction unit container for targeted mixing of exhaust gases with the air volume contained in the suction unit container.

An exhaust gas recirculation system is provided for an internal combustion engine having reciprocating piston design with an exhaust gas turbocharger unit having an exhaust gas turbine and a supercharger. The internal combustion engine has a machine housing accommodating one or more cylinders having reciprocating pistons, which is provided with a suction unit and an exhaust gas outlet unit, which is connected to the exhaust gas turbine by way of an exhaust gas line. The exhaust gas line supplies at least a part of the exhaust gas stream to the suction unit via the exhaust gas recirculation system. To optimize the exhaust gas recirculation system, it has a pipe branch, which is connected to the exhaust gas line and is connected to an exhaust gas recirculation line with a control element interconnected. The exhaust gas recirculation line extends, on the one hand, with a first supply line section outside and, on the other hand, with a second supply line section in an interior of, a suction unit container of the suction unit. An exhaust gas stream is conveyed by the second supply line section into the suction unit container for targeted mixing of exhaust gases with the air volume contained in the suction unit container.

Systems and methods for implementing regeneration of an aftertreatment component using exhaust gas recirculation is described. According to various embodiments, an engine system comprises an engine, a turbocharger, a fluid control valve, and a lean NO.sub.x catalyst. The engine has a first set cylinders fluidly coupled to an intake manifold and a second set of cylinders having fluidly isolated from the intake manifold of the engine. The fluid control valve is disposed between the first exhaust outlet and the exhaust conduit and is structured to selectively fluidly couple the first exhaust outlet to the exhaust conduit. Also, the lean NO.sub.x catalyst has an inlet structured to receive exhaust gases from the exhaust conduit at a position downstream of the turbine outlet and the fluid control valve.

Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Methods and systems are provided for exhaust gas heat recovery and exhaust gas recirculation (EGR) cooling using a single split heat exchanger. Exhaust heat from each of a first portion of exhaust routed to the intake manifold as EGR and a second portion of exhaust diverted via a bypass passage for exhaust heat recovery may be transferred to a coolant flowing through the heat exchanger. The direction of coolant flow via the heat exchanger may be adjusted based on the coolant temperature.

A cylinder gas recirculation system device of an internal combustion engine based on pressure differential driving is provided, the overall device includes a recirculation intake and exhaust system and a gas storage system. An intake control valve on a cylinder block, a surge tank, and an exhaust control valve on the cylinder block are sequentially connected to form a gas recirculation subsystem of the cylinder block of the internal combustion engine. Two adjacent subsystems are in communication through an intake pipe. Positions of intake and exhaust pipelines may be anywhere between the top and bottom dead centers of a piston in a cylinder, and intake and exhaust valves of the gas recirculation may share the same valve. Different valves may also be used, and the intake and exhaust pipelines of the gas recirculation are arranged on the same side of the cylinder in double layers.