| 摘要 |
PURPOSE:To improve the durability of a heat exchanger by a method wherein coolant and exhaust gas are heat-exchanged through the heat exchanger and an exhaust gas heat exchanger, both of which are contacted with each other only during the time when the heat pump is put into operation, and the heat exchanger is prevented from becoming high temperatures by separating the heat exchanger from the exhaust gas heat exchanger when exhaust gas becomes high temperatures or the like. CONSTITUTION:The heat exchanger 19 is so constituted as to be able to contact with the separate from the exhaust gas heat exchanger 3 by being shifted through a motor 23, a screw 24 and a spring 25 by the use of flexible tubes 18a and 18b in the coolant passages before and after the heat exchanger 19. When the heating is intended by recovering the heat of exhaust gas by means of heat pump system, the heat exchanger 19 and the exhaust gas heat exchanger 3 are brought into contact with each other so that the heat is exchanged from exhaust gas into coolant and, after that, radiated from an interior heat exchanger 17. On the other hand, when the heating with coolant is not necessary, the heat exchanger 19 and the exhaust gas heat exchanger 3 are separated from each other so that the heat does not exchanged from exhaust gas into coolant. Consequently, the deterioration of the heat exchanger 19 due to high temperature and the thermal cracking of coolant are prevented, resulting in enabling to improve the durability of the heat exchanger. |
