A computer control network is connected to a multiple-cylinder engine and implements aftertreatment temperature management. Processors are configured to determine an aftertreatment temperature-efficient air to fuel ratio that satisfies the sensed power output request, determine an air to fuel ratio adjustment, select an in-cylinder exhaust gas recirculation technique, select at least one EGR cylinder of the multiple-cylinder engine to implement the in-cylinder exhaust gas recirculation technique, and control the intake valves to open and the exhaust valves to close for the selected at least one EGR cylinder to adjust the oxygen and particulate content of the exhaust gas by applying at least a second compression stroke of the respective reciprocating piston of the at least one EGR cylinder to the exhaust gas to push the exhaust gas through to the intake manifold.

A method includes substantially eliminating surge of a compressor and reducing specific fuel consumption and exhaust emissions of an engine by adjusting exhaust flow through an exhaust gas recirculation system, by adjusting airflow through a compressor recirculation valve, by adjusting fuel injection timing, or by adjusting a combination thereof in response to variance in a plurality of parameters. The parameters include quantity of exhaust emissions, a maximum in-cylinder pressure of the engine, an area ratio of an exhaust gas recirculation mixer of the exhaust gas recirculation system, estimated or sensed compressor surge, engine load, altitude of operation, or combinations of the parameters thereof.

An exhaust gas recirculation apparatus including an engine; a suction line; an exhaust line; a post-processing unit which is disposed in the exhaust line to reduce hazardous substances contained in the exhaust gas; a first circulation line which guides a part of the exhaust gas, which is guided to the exhaust line, to the suction line; a second circulation line which guides a part of the exhaust gas, which is guided to a downstream side of the post-processing unit, to the suction line; and a bypass line which branches off from an upstream side of the second circulation line, and merges with a downstream side of the second circulation line, wherein ammonia slip, which is discharged from the post-processing unit, is prevented from being guided to the suction line.

An exhaust gas recirculation apparatus including an engine; a suction line; an exhaust line; a post-processing unit which is disposed in the exhaust line to reduce hazardous substances contained in the exhaust gas; a first circulation line which guides a part of the exhaust gas, which is guided to the exhaust line, to the suction line; a second circulation line which guides a part of the exhaust gas, which is guided to a downstream side of the post-processing unit, to the suction line; and a bypass line which branches off from an upstream side of the second circulation line, and merges with a downstream side of the second circulation line, wherein ammonia slip, which is discharged from the post-processing unit, is prevented from being guided to the suction line.

An engine system includes: an engine including a plurality of combustion chambers generating driving torque by combustion of fuel; an exhaust gas purification apparatus installed at an exhaust line in which exhaust gas exhausted from the combustion chambers flows; a bypass line branched from the exhaust line at an upstream side of the exhaust gas purification apparatus and joining the exhaust line at a downstream side of the exhaust gas purification apparatus so that the exhaust gas flowing in the exhaust line bypasses the exhaust gas purification apparatus; and a bypass valve installed at the bypass line.

An engine system includes: an engine including a plurality of combustion chambers generating driving torque by combustion of fuel; an exhaust gas purification apparatus installed at an exhaust line in which exhaust gas exhausted from the combustion chambers flows; a bypass line branched from the exhaust line at an upstream side of the exhaust gas purification apparatus and joining the exhaust line at a downstream side of the exhaust gas purification apparatus so that the exhaust gas flowing in the exhaust line bypasses the exhaust gas purification apparatus; and a bypass valve installed at the bypass line.

A method of controlling exhaust gas recirculation (EGR) in a turbocharged compression-ignition engine system including an engine, an induction subsystem in upstream communication with the engine, an exhaust subsystem in downstream communication with the engine, a high pressure EGR path between the exhaust and induction subsystems upstream of a turbocharger turbine and downstream of a turbocharger compressor, and a low pressure EGR path between the exhaust and induction subsystems downstream of the turbocharger turbine and upstream of the turbocharger compressor. A target total EGR fraction for compliance with exhaust emissions criteria is determined, then a target HP/LP EGR ratio is determined to optimize other engine system criteria within the constraints of the determined target total EGR fraction.

An exhaust heat recovery device includes a heat exchanger that performs heat exchange between exhaust gas flowing in from a first exhaust gas conduit and a fluid as a heated object. Regarding the heat exchanger, a flow passage for the exhaust gas inside the shell is configured so that the exhaust gas flowing in from the exhaust gas inflow passage reaches a branch after contacting a plate in a division area and the exhaust gas not branched to an exhaust gas recirculation flow passage at the branch flows out to a second exhaust gas conduit after contacting a plate in a division area.

An exhaust heat recovery device includes a heat exchanger that performs heat exchange between exhaust gas flowing in from a first exhaust gas conduit and a fluid as a heated object. Regarding the heat exchanger, a flow passage for the exhaust gas inside the shell is configured so that the exhaust gas flowing in from the exhaust gas inflow passage reaches a branch after contacting a plate in a division area and the exhaust gas not branched to an exhaust gas recirculation flow passage at the branch flows out to a second exhaust gas conduit after contacting a plate in a division area.

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.