Abstract: Disclosed is a heat exchanger, in particular for motor vehicles, having a large number of flat tubes which contain indentations (“winglets”) and through which a fluid cooling medium can flow, and having corrugated fins which are associated with these flat tubes and to which environmental air or other media can be applied. In addition, there is disclosed a method for producing flat tubes of this type (“winglet tubes”) and for assembling these flat tubes into heat exchangers.

Abstract: A multi-chamber tube for a heat exchanger arrangement of a motor vehicle has at least two chamber sections which extend parallel to each other and side-by-side. Different liquid or gaseous heat transfer media are used in the chamber sections which have widths significantly greater than their heights. At least one chamber section has a greater height than at least one other chamber section. The multi-chamber tube is used in a coolant radiator and charge air cooler combination.

Abstract: Method and apparatus for forming a tubular heat-exchanger header includes a tool die having a chamber dimensioned to receive the header, the chamber conforming to an outer peripheral contour of the header. A plurality of guide passages are formed through the tool die for insertion of a corresponding number of punches. The guide passages expose the areas of the header to be pierced for forming the openings. The ends of the tubular header are each sealed with a stopper. Fluid is supplied into the header using a fluid supply through one of the stoppers and the pressure is raised to a predetermined internal pressure. While the pressure is maintained, the punches are passed through the guide passages to simultaneously pierce through the header wall to form the openings. The header thus formed has an inwardly directed rim around each opening, which rim sealingly bears against the periphery of the punch to maintain the pressure during piercing.