A heat exchanger includes a plurality of heat transfer tubes (3) and a centrally arranged bypass tube (4), which are held each between a tube plate (5) of a gas inlet chamber (7) and a tube plate (6) of a gas outlet chamber (8) that are connected to a cylindrical jacket. A coolant (11) is introduced into the jacket space (9) enclosing the tubes (3, 4). A control device (16), includes a throttle valve (18) and a drive (19), sets a gas outlet temperature range of the heat exchanger (1). A discharge rate and a discharged quantity of an uncooled process gas stream (14) from the bypass tube is controlled by the throttle valve, at an outlet end (17) of the bypass tube and is adjustable via the control device. The throttle valve is formed of a material resistant to high-temperature corrosion in a temperature range sensitive for high-temperature corrosion.

An exhaust heat recovery device includes: a first flow path member; a second flow path member adjacent to the first flow path member, and which includes a heat exchange unit configured to perform heat exchange between exhaust gas flowing in the second flow path and a refrigerant; a valve mechanism configured to switch between opening and closing of the first flow path and the second flow path; and a drive unit which includes a drive shaft configured to rotate the rotation shaft portion. The second flow path member is inclined with respect to a flow direction of the exhaust gas in the first flow path, and the drive shaft extends toward the first flow path member and is connected to the rotation shaft portion in a region formed on a lateral side of the second flow path member when viewed in an axial direction of the drive shaft.

An exhaust heat recovery device includes: a first flow path member; a second flow path member adjacent to the first flow path member, and which includes a heat exchange unit configured to perform heat exchange between exhaust gas flowing in the second flow path and a refrigerant; a valve mechanism configured to switch between opening and closing of the first flow path and the second flow path; and a drive unit which includes a drive shaft configured to rotate the rotation shaft portion. The second flow path member is inclined with respect to a flow direction of the exhaust gas in the first flow path, and the drive shaft extends toward the first flow path member and is connected to the rotation shaft portion in a region formed on a lateral side of the second flow path member when viewed in an axial direction of the drive shaft.

A valve device increases or decreases a flow rate of EGR gas. The valve device includes a housing, a bypass valve body, and an EGR valve body. The housing includes a first upstream passage into which the EGR gas cooled by an EGR cooler flows, a second upstream passage into which the EGR gas that bypasses the EGR cooler flows, and a downstream passage connected to the first upstream passage and the second upstream passage, and provided downstream with respect to the first upstream passage and the second upstream passage. The bypass valve body opens and closes the second upstream passage. The EGR valve body is provided in the downstream passage and rotates around an EGR valve axis to open and close the downstream passage.

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.

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.

Methods and systems are provided for directing the flow of recirculated exhaust gas (EGR) delivered to an EGR cooler. In one example, a method includes flowing EGR through an EGR cooler positioned in an EGR passage, the EGR cooler comprising a bypass passage, a first cooler core flow path, and a second cooler core flow path, and adjusting a valve of the EGR cooler to selectively block flow of the EGR through the bypass passage, the first cooler core flow path, and the second cooler core flow path. In this way, fouling of the EGR cooler may be reduced.

Methods and systems are provided for directing the flow of recirculated exhaust gas (EGR) delivered to an EGR cooler. In one example, a method includes flowing EGR through an EGR cooler positioned in an EGR passage, the EGR cooler comprising a bypass passage, a first cooler core flow path, and a second cooler core flow path, and adjusting a valve of the EGR cooler to selectively block flow of the EGR through the bypass passage, the first cooler core flow path, and the second cooler core flow path. In this way, fouling of the EGR cooler may be reduced.

Methods and systems are provided for cooling an aftertreatment device with exhaust gas. In one example, an exhaust system comprises a recirculation passage branching from an EGR passage from downstream of an EGR cooler to a portion of an exhaust passage between the EGR passage and an aftertreatment device. In one example, the aftertreatment device is an SCR device.

Methods and systems are provided for cooling an aftertreatment device with exhaust gas. In one example, an exhaust system comprises a recirculation passage branching from an EGR passage from downstream of an EGR cooler to a portion of an exhaust passage between the EGR passage and an aftertreatment device. In one example, the aftertreatment device is an SCR device.