Exhaust Heat Recovery Device

摘要

An exhaust heat recovery device provided with a Rankine cycle, capable of preventing opportunities for actuating the Rankine cycle from being decreased and capable of efficiently operating the Rankine cycle. An exhaust heat recovery device 1 recovering and using exhaust heat of an engine 10 includes: a Rankine cycle 2 including a heater 22, an expander 23, a condenser 24, and a pump 25; a bypass flow passage 26 allowing the refrigerant to circulate while bypassing the expander 23; a bypass valve 27 opening and closing the bypass flow passage 26; and a control unit 4. When starting up the Rankine cycle 2, the control unit 4 executes start-up control of the Rankine cycle 2 in which the pump 25 is actuated with the bypass valve 27 open and then the bypass valve 27 is closed. Furthermore, the control unit 4 repeatedly executes the start-up control when the pressure difference between the high-pressure side and the low-pressure side of the Rankine cycle 2 after closing the bypass valve 27 does not reach the start-up completion determination value within a predetermined time.

主权项

1. An exhaust heat recovery device comprising:
a Rankine cycle in which a heater configured to heat and vaporize refrigerant by exhaust heat of an external heat source, an expander configured to generate power by expanding the refrigerant passed through the heater, a condenser configured to condense the refrigerant passed through the expander, and a pump configured to send the refrigerant passed through the condenser to the heater are disposed in a circulation passage of the refrigerant; a bypass flow passage that allows the refrigerant to circulate while bypassing the expander; a bypass valve that opens and closes the bypass flow passage; a pressure difference determining unit that determines a pressure difference between a high-pressure side and a low-pressure side of the Rankine cycle; and a control unit that executes start-up control of the Rankine cycle, the start-up control actuating the pump with the bypass valve open and then closing the bypass valve, wherein the control unit repeatedly executes the start-up control when the pressure difference after closing the bypass valve does not reach a start-up completion determination value of the Rankine cycle within a predetermined time.