An EGR cooler may include an EGR cooler housing having top, bottom and side walls, inlet and outlet end walls disposed at opposite ends, and a longitudinal axis extending in a direction of exhaust gas flow from the inlet end to the outlet end. A plurality of cooling tubes extend through the EGR cooler between the top and bottom walls, and are arranged in a cooling tube array to form an exhaust gas receiving area at an upstream side of the cooling tube array proximate the inlet end wall so that exhaust gas flowing into the EGR cooler through an exhaust gas inlet opening will flow into the exhaust gas receiving area and then disperse through the cooling tube array. A pitch distance between the cooling tubes may be greater proximate the longitudinal axis than proximate the side walls to promote flow through, instead of around, the cooling tube array.

An EGR cooler may include an EGR cooler housing having top, bottom and side walls, inlet and outlet end walls disposed at opposite ends, and a longitudinal axis extending in a direction of exhaust gas flow from the inlet end to the outlet end. A plurality of cooling tubes extend through the EGR cooler between the top and bottom walls, and are arranged in a cooling tube array to form an exhaust gas receiving area at an upstream side of the cooling tube array proximate the inlet end wall so that exhaust gas flowing into the EGR cooler through an exhaust gas inlet opening will flow into the exhaust gas receiving area and then disperse through the cooling tube array. A pitch distance between the cooling tubes may be greater proximate the longitudinal axis than proximate the side walls to promote flow through, instead of around, the cooling tube array.

A system for connecting housing elements of a device for heat transfer having a housing with a first housing element and a second housing element which are connectable with one another with face sides oriented toward one another and via a connection under form closure. Housing elements are herein in contact on another with side margins developed in proximity of front faces. The first latching elements are implemented as recesses each with a flat surface oriented in parallel to front face. On an outer side of side margin of first housing element between each first latching element and front face, a shaping is developed protruding from side margin, which comprises on a side facing first latching element a flat surface disposed in the plane spanned by flat surface of first latching element. Flat surfaces of first latching element and the shaping form a contiguous bearing area for second latching element.

A system for connecting housing elements of a device for heat transfer having a housing with a first housing element and a second housing element which are connectable with one another with face sides oriented toward one another and via a connection under form closure. Housing elements are herein in contact on another with side margins developed in proximity of front faces. The first latching elements are implemented as recesses each with a flat surface oriented in parallel to front face. On an outer side of side margin of first housing element between each first latching element and front face, a shaping is developed protruding from side margin, which comprises on a side facing first latching element a flat surface disposed in the plane spanned by flat surface of first latching element. Flat surfaces of first latching element and the shaping form a contiguous bearing area for second latching element.

A heat exchanger disposed on a downstream side of a gas flow passage of combustion exhaust gas ejected from a burner comprising a plurality of heat exchange units stacked in a gas flow passage direction of the combustion exhaust gas, an inlet pipe, and an outlet pipe, wherein the inlet pipe and the outlet pipe are provided so as to protrude from a most downstream heat exchange unit located on a most downstream side of the gas flow passage of the combustion exhaust gas toward the downstream side of the gas flow passage of the combustion exhaust gas.

A heat exchanger disposed on a downstream side of a gas flow passage of combustion exhaust gas ejected from a burner comprising a plurality of heat exchange units stacked in a gas flow passage direction of the combustion exhaust gas, an inlet pipe, and an outlet pipe, wherein the inlet pipe and the outlet pipe are provided so as to protrude from a most downstream heat exchange unit located on a most downstream side of the gas flow passage of the combustion exhaust gas toward the downstream side of the gas flow passage of the combustion exhaust gas.

An exhaust gas recirculation cooler may include a housing having a coolant inlet opening into an inlet region and a coolant outlet, and a plurality of cooling tubes arranged in the housing next to one another to form a tube row, each cooling tube connecting an exhaust gas inlet and outlet. At least two tube rows with one arranged on top of another and spaced from each other may form a tube block. Exhaust gas may be flowable through an inside of each cooling tube, and a coolant flow may be able to be circulated outside of the cooling tubes within the housing and flowable through an annular space enclosing the tube block in a circumferential direction. A flow guide arrangement for guiding the coolant in the interior of the tube block may be arranged in the housing lying against at least portions of one of the tube rows.

An exhaust gas recirculation cooler may include a housing having a coolant inlet opening into an inlet region and a coolant outlet, and a plurality of cooling tubes arranged in the housing next to one another to form a tube row, each cooling tube connecting an exhaust gas inlet and outlet. At least two tube rows with one arranged on top of another and spaced from each other may form a tube block. Exhaust gas may be flowable through an inside of each cooling tube, and a coolant flow may be able to be circulated outside of the cooling tubes within the housing and flowable through an annular space enclosing the tube block in a circumferential direction. A flow guide arrangement for guiding the coolant in the interior of the tube block may be arranged in the housing lying against at least portions of one of the tube rows.

Various methods and systems are provided for an exhaust gas recirculation cooler including a plurality of cooling tubes. In one example, an exhaust gas recirculation (EGR) cooler includes a plurality of cooling tubes positioned within a housing of the EGR cooler, each cooling tube of the plurality of cooling tubes extending between and directly coupled to tube sheets of the EGR cooler at ends of each cooling tube, where at least one end of one or more cooling tubes of a first portion of the plurality of cooling tubes, inward of a tube sheet coupled to the at least one end, includes a compliant region, where the first portion is positioned proximate to an exhaust inlet of the EGR cooler.

Various methods and systems are provided for an exhaust gas recirculation cooler including a plurality of cooling tubes. In one example, an exhaust gas recirculation (EGR) cooler includes a plurality of cooling tubes positioned within a housing of the EGR cooler, each cooling tube of the plurality of cooling tubes extending between and directly coupled to tube sheets of the EGR cooler at ends of each cooling tube, where at least one end of one or more cooling tubes of a first portion of the plurality of cooling tubes, inward of a tube sheet coupled to the at least one end, includes a compliant region, where the first portion is positioned proximate to an exhaust inlet of the EGR cooler.