An internal combustion engine includes an intercooler configured to cool an intake gas compressed by a compressor, a cooler bypass passage configured to bypass the intercooler, and a cooler bypass valve configured to open and close the cooler bypass passage, and an exhaust gas recirculation gas is introduced into an upstream side of the intercooler. An electronic control unit is configured to open the cooler bypass valve during use of a high exhaust gas recirculation rate region, and to close the cooler bypass valve during use of a low exhaust gas recirculation rate region.

In a casing, a cooler valve element is placed in a cooler flow passage, while a bypass valve element is placed in a bypass flow passage. The cooler valve element is adjacent and fixed to a first shaft end portion of a valve shaft. The bypass valve element is adjacent and fixed to a second shaft end portion of the valve shaft. A first bearing is provided between the casing and the first shaft end portion and a second bearing is provided between the casing and the second shaft end portion. A first seal member is placed, adjacent to the first bearing, and a second seal member is placed adjacent to a second bearing. A driven gear is fixed to a leading end of the first shaft end portion. The first bearing consists of a rolling bearing and the second bearing is formed of a slid bearing.

In a casing, a cooler valve element is placed in a cooler flow passage, while a bypass valve element is placed in a bypass flow passage. The cooler valve element is adjacent and fixed to a first shaft end portion of a valve shaft. The bypass valve element is adjacent and fixed to a second shaft end portion of the valve shaft. A first bearing is provided between the casing and the first shaft end portion and a second bearing is provided between the casing and the second shaft end portion. A first seal member is placed, adjacent to the first bearing, and a second seal member is placed adjacent to a second bearing. A driven gear is fixed to a leading end of the first shaft end portion. The first bearing consists of a rolling bearing and the second bearing is formed of a slid bearing.

An exhaust gas recirculation system for an internal combustion engine is provided. The exhaust gas recirculation system includes: an EGR passage configured to connect an exhaust gas passage of the internal combustion engine with an intake air passage; an EGR cooling system arranged at the EGR passage; and a control device configured to control the EGR cooling system. The control device is configured to provide feedback control of the cooling efficiency of the EGR cooling system to cause the temperature of intake gas suctioned into a cylinder of the internal combustion engine to approach a target intake gas temperature. The control device is configured to more increase the amount of change of the cooling efficiency when the flow rate of EGR gas recirculated is less.

An exhaust gas recirculation system for an internal combustion engine is provided. The exhaust gas recirculation system includes: an EGR passage configured to connect an exhaust gas passage of the internal combustion engine with an intake air passage; an EGR cooling system arranged at the EGR passage; and a control device configured to control the EGR cooling system. The control device is configured to provide feedback control of the cooling efficiency of the EGR cooling system to cause the temperature of intake gas suctioned into a cylinder of the internal combustion engine to approach a target intake gas temperature. The control device is configured to more increase the amount of change of the cooling efficiency when the flow rate of EGR gas recirculated is less.

An engine includes an exhaust manifold, an intake manifold, and an EGR device configured to supply EGR gas from the exhaust manifold to the intake manifold. A longitudinal direction of the EGR cooler is in an up-down direction of the engine in a used state. The exhaust manifold has an EGR pipe that is connected to an EGR cooler, and a part of the EGR pipe extends in left-and-right directions. The part of the EGR pipe is provided at a side where a flywheel housing is provided. An upper end of the EGR cooler has a supply port into which the EGR gas is supplied from the exhaust manifold. The part of the EGR pipe and the flywheel housing are located in an up-down directions.

A system and method to perform bypass actuation detection includes alternating control of a bypass valve within an exhaust gas recirculation (EGR) system of a vehicle to direct flow of gas through a cooler module or a bypass module within the EGR system. The method also includes determining a position of an EGR valve that directs the gas into the EGR system, and verifying operation of the bypass valve based on the position of the EGR valve.

A system and method to perform bypass actuation detection includes alternating control of a bypass valve within an exhaust gas recirculation (EGR) system of a vehicle to direct flow of gas through a cooler module or a bypass module within the EGR system. The method also includes determining a position of an EGR valve that directs the gas into the EGR system, and verifying operation of the bypass valve based on the position of the EGR valve.

A system and method to perform bypass actuation detection includes alternating control of a bypass valve within an exhaust gas recirculation (EGR) system of a vehicle to direct flow of gas through a cooler module or a bypass module within the EGR system. The method also includes determining a position of an EGR valve that directs the gas into the EGR system, and verifying operation of the bypass valve based on the position of the EGR valve.

A system and method to perform bypass actuation detection includes alternating control of a bypass valve within an exhaust gas recirculation (EGR) system of a vehicle to direct flow of gas through a cooler module or a bypass module within the EGR system. The method also includes determining a position of an EGR valve that directs the gas into the EGR system, and verifying operation of the bypass valve based on the position of the EGR valve.