US Patent 10234211 Heat exchanger

A core unit 1 of a heat exchanger includes a plurality of core plates that are stacked on one another to alternately constitute oil passages 10 and cooling water passages 11, in which oil that is heat-exchanged in the core unit 1 is guided to an outlet port 23 after passing through a top connecting passage 18 and an oil outlet passage L3, and in which part of the oil is led from a lower end of an upper/lower oil passage L2 is guided to the outlet port 23 through an auxiliary passage 24, so that the amount of oil flowing in the oil outlet passage L3 is reduced thereby reducing a passage resistance.