Abstract: A heat exchanger core (20) has tubes (22) which are stiffer and more resistant to core assembly compression at the elongated tube edges (24). Corrugated cooling fins (46) stacked between the tubes (22) have fin walls (48) that cross the stiffer tube edges (24) and a series of vane like louvers (54, 56) that are regularly spaced along the fin walls (48). The outboard louvers (56) on both sides of each fin wall (48) are strategically shortened, as compared to the longer inboard louvers (54) so that the fin walls (48) will be stiffened less, and less subject to buckling when the core (20) is stacked during assembly.

Abstract: According to the present invention, in a corrugated fin type heat exchanger including a core portion having a plurality of flat tubes disposed in parallel relation with regard to a flow direction of air and at least one corrugated fin disposed between each pair of the flat tubes, a height of a flow space within the flat tube is in a range of 0.6-1.2 mm, a height of the corrugated fin is in a range of 3-6 mm, and a ratio (St/W.times.D) of the cross-sectional area (W.times.D) expressed by an overall width dimension (W) and a thickness dimension (D) of the core portion to a total cross-sectional flow passage area (St) of the plurality of flat tubes is set to a range of 0.07-0.24 according to the height of the flow space of the flat tube and the height of the corrugated fin.