Patent ID: 8316927

Claim:
A waste heat recovery device, comprising: a heat pipe in which a working fluid for transporting heat is enclosed, wherein the heat pipe has a heating part for heating and evaporating the working fluid and a cooling part for cooling and condensing the evaporated working fluid; and a mode-switching valve, which switches a heat recovery mode for recovering heat of exhaust gas by using the heat pipe, and a heat insulation mode for stopping a heat transport from the heating part to the cooling part, wherein: the heating part is made of a steel through which hydrogen gas permeates at about 500 ° C. and higher; wherein the mode switching valve is disposed in a passage between the heating part and the cooling part at a downstream side of the cooling part and is a diaphragm valve having a diaphragm which displaces in accordance with a pressure difference between a pressure of the working fluid at the downstream side of the cooling part and a pressure introduced from air outside of the heat pipe into a diaphragm room partitioned from the working fluid within the heat pipe; and the mode switching valve is open or closed in accordance with the pressure difference.