Heat exchanger e.g. counter flow heat exchanger, for e.g. diesel engine of motor vehicle, has exchange element whose thermal conductance can be modified, and two fins respectively arranged on external surface and internal surface of walls

摘要

The exchanger (1) has an exchange element (15) for separating an exhaust gas and a coolant, where a thermal conductance of the element can be modified. The element has an intermediate wall (3) and an internal wall (4) for defining a thin isolating porous layer (5) between the walls. An extraction pipe (10) extracts air contained in space defined by the walls or injects air in the space. Two fins are respectively arranged on an external surface and an internal surface of the intermediate wall and the internal wall.