HEAT EXCHANGER UNIT AND METHOD FOR FLUID TO PASSIVELY BYPASSING A HEAT EXCHANGER

The invention relates to a heat exchanger unit for an exhaust gas system. The heat exchanger unit comprises an inlet for a fluid flow to enter the heat exchanger unit and an outlet for a fluid flow to exit the heat exchanger unit. The heat exchanger unit comprises a heat exchanger having a heat exchanger conduit passing through the heat exchanger and at least one bypass conduit bypassing the heat exchanger, wherein the at least one bypass conduit comprises a bypass core having a plurality of channels arranged longitudinally along the bypass conduit.