One or more techniques and/or systems are disclosed for controlling exhaust heating to reduce engine out NO.sub.x emission. A heater is used for exhaust temperature control of an exhaust system and is activated at a non-active selective catalytic reduction (SCR) system temperature. One or more exhaust air flow bypasses are controlled during operation of the heater and heating of an exhaust air flow is maintained by the heater prior to activation of the SCR system.

An engine system, includes a bypass line branched from an intake line upstream of an intercooler and joining the intake line downstream of the intercooler; a condensed water separation line branched from the intake line upstream of the intercooler and joining the intake line upstream of the intercooler; a condensed water separation module provided in the condensed water separation line and configured to separate condensed water contained in a mixture flowing through the condensed water separation line; and a four-way valve provided in the intake line between a compressor and the intercooler, and selectively operated so that the mixture of the outside air and the recirculation gas introduced to the upstream of the intercooler passes through the intercooler, flows through the bypass line, or flows through the condensed water separation line.

An engine system, includes a bypass line branched from an intake line upstream of an intercooler and joining the intake line downstream of the intercooler; a condensed water separation line branched from the intake line upstream of the intercooler and joining the intake line upstream of the intercooler; a condensed water separation module provided in the condensed water separation line and configured to separate condensed water contained in a mixture flowing through the condensed water separation line; and a four-way valve provided in the intake line between a compressor and the intercooler, and selectively operated so that the mixture of the outside air and the recirculation gas introduced to the upstream of the intercooler passes through the intercooler, flows through the bypass line, or flows through the condensed water separation line.

An engine system, includes a bypass line branched from an intake line upstream of an intercooler and joining the intake line downstream of the intercooler; a condensed water separation line branched from the intake line upstream of the intercooler and joining the intake line upstream of the intercooler; a condensed water separation module provided in the condensed water separation line and configured to separate condensed water contained in a mixture flowing through the condensed water separation line; and a four-way valve provided in the intake line between a compressor and the intercooler, and selectively operated so that the mixture of the outside air and the recirculation gas introduced to the upstream of the intercooler passes through the intercooler, flows through the bypass line, or flows through the condensed water separation line.

An engine system, includes a bypass line branched from an intake line upstream of an intercooler and joining the intake line downstream of the intercooler; a condensed water separation line branched from the intake line upstream of the intercooler and joining the intake line upstream of the intercooler; a condensed water separation module provided in the condensed water separation line and configured to separate condensed water contained in a mixture flowing through the condensed water separation line; and a four-way valve provided in the intake line between a compressor and the intercooler, and selectively operated so that the mixture of the outside air and the recirculation gas introduced to the upstream of the intercooler passes through the intercooler, flows through the bypass line, or flows through the condensed water separation line.

An exhaust gas recirculation (EGR) cooler includes: a housing including a cavity in which a plurality of tubes are received, and including a coolant inlet conduit allowing a coolant to flow into the cavity therethrough and a coolant outlet conduit allowing the coolant to be discharged from the cavity therethrough; a bypass conduit provided in parallel to the housing; an inlet header sealingly mounted on a first end portion of the housing; and an outlet header sealingly mounted on a second end portion of the housing. The inlet header may include an EGR valve housing, a bypass valve housing, and a cooling chamber defined in the EGR valve housing and the bypass valve housing, and the cooling chamber may be fluidly connected to the cavity of the housing through the coolant outlet conduit.

A system and method of exhaust gas recirculation (EGR) in an internal combustion engine are provided. The EGR system includes a first EGR flow path and a second EGR flow path independent of the first EGR flow path that are each configured to recirculate high pressure exhaust from the exhaust system back to the engine intake system. The system includes a controller in operable communication with the EGR system configured to selectively control an amount of EGR flow through at least one of the first and second EGR flow paths.

A method for operating an internal combustion engine, which comprises a combustion unit, a generator coupled with the combustion unit, a fresh gas tract, an exhaust tract, an exhaust gas recirculation line, which branches off of the exhaust tract and opens into the fresh gas tract, and at least one electrical heating device, which is integrated into the exhaust tract or into the exhaust gas recirculation line, characterized in that, during an overrun mode of the combustion unit, the heating device is operated with energy provided by the generator, and exhaust gas heated with the aid of the heating device is partially or completely guided via the exhaust gas recirculation line.

A method for operating an internal combustion engine, which comprises a combustion unit, a generator coupled with the combustion unit, a fresh gas tract, an exhaust tract, an exhaust gas recirculation line, which branches off of the exhaust tract and opens into the fresh gas tract, and at least one electrical heating device, which is integrated into the exhaust tract or into the exhaust gas recirculation line, characterized in that, during an overrun mode of the combustion unit, the heating device is operated with energy provided by the generator, and exhaust gas heated with the aid of the heating device is partially or completely guided via the exhaust gas recirculation line.

A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.