WASTE HEAT RECOVERY APPARATUS AND METHOD FOR CONTROLLING WASTE HEAT RECOVERY APPARATUS

• US 20180266360A1
• Filed: 03/15/2018
• Published: 09/20/2018
• Est. Priority Date: 03/17/2017
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: TATENO, Manabu
• Granted Patent: US 10,641,203 B2
• Time in Patent Office: Days
• CPC Class Codes: F01D 15/08 Adaptations for driving, or combinations with, pumps
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 23/065 the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
• CPC Class Codes: F01K 23/101 Regulating means specially adapted therefor F01K23/105, F01K23/108 take precedence
• CPC Class Codes: F01P 2050/24 Hybrid vehicles
• CPC Class Codes: F01P 7/162 by cutting in and out of pumps
• CPC Class Codes: F02G 2260/00 Recuperating heat from exhaust gases of combustion engines and heat from cooling circuits
• CPC Class Codes: F02G 5/04 in combination with other waste heat from combustion engines

Abstract

A waste heat recovery apparatus includes an evaporator, an expander, a condenser, a liquid-phase refrigerant supply device, and a control device. The control device is configured to control the liquid-phase refrigerant supply device so as to bring the supply of the liquid-phase refrigerant by the liquid-phase refrigerant supply device into a stopped state at least until an amount of the liquid-phase refrigerant stored in the evaporator becomes equal to or lower than a predetermined low refrigerant amount, during operation of the internal combustion engine.

Claims

1. A waste heat recovery apparatus comprising:

an evaporator configured to turn a liquid-phase refrigerant into steam through heat exchange with exhaust gas of an internal combustion engine;

an expander configured to expand a gas-phase refrigerant passed through the evaporator to recover heat energy;

a condenser configured to condense the gas-phase refrigerant passed through the expander such that the gas-phase refrigerant returns to the liquid-phase refrigerant;

a liquid-phase refrigerant supply device configured to supply the liquid-phase refrigerant delivered from the condenser, to the evaporator; and

a control device configured to control the liquid-phase refrigerant supply device so as to adjust an amount of the liquid-phase refrigerant to be supplied to the evaporator,

wherein the control device is configured to control the liquid-phase refrigerant supply device so as to bring the supply of the liquid-phase refrigerant by the liquid-phase refrigerant supply device into a stopped state at least until an amount of the liquid-phase refrigerant stored in the evaporator becomes equal to or lower than a predetermined low refrigerant amount, during operation of the internal combustion engine.

2. The waste heat recovery apparatus according to claim 1, wherein:

the liquid-phase refrigerant supply device is a pump that pumps the liquid-phase refrigerant delivered from the condenser to the evaporator; and

the control device is configured to stop operation of the pump when the supply of the liquid-phase refrigerant is brought into a stopped state.

3. The waste heat recovery apparatus according to claim 2, wherein the control device is configured to continue a state where the operation of the pump is stopped, during the operation of the internal combustion engine and even after the amount of the liquid-phase refrigerant stored in the evaporator becomes equal to or lower than the low refrigerant amount.

4. The waste heat recovery apparatus according to claim 2, wherein the control device is configured to operate the pump during the operation of the internal combustion engine and in a case where the amount of the liquid-phase refrigerant stored in the evaporator becomes equal to or lower than the low refrigerant amount.

5. The waste heat recovery apparatus according to claim 2, wherein:

the control device is configured to operate the pump during stop of the internal combustion engine and in a case where a temperature of the liquid-phase refrigerant stored in the evaporator reaches a boiling temperature; and

the control device is configured to bring the pump into a stopped state during the stop of the internal combustion engine and when the temperature of the liquid-phase refrigerant stored in the evaporator does not reach the boiling temperature.

6. The waste heat recovery apparatus according to claim 4, wherein:

the control device is configured to calculate an amount of a refrigerant needed to bring the amount of the liquid-phase refrigerant stored in the evaporator into a full amount as a target refrigerant amount; and

the control device is configured to control the operation of the pump with the target refrigerant amount as an upper limit.

7. The waste heat recovery apparatus according to claim 2, further comprising:

a heat recovery device that performs heat exchange between the liquid-phase refrigerant passed through the pump, and an engine coolant passed through the internal combustion engine; and

a pumping device that pumps the engine coolant to the heat recovery device,

wherein the control device is configured to operate the pumping device in a case where the pump is operated and in a case where a temperature of the engine coolant is higher than a temperature of the liquid-phase refrigerant passed through the pump.

8. The waste heat recovery apparatus according to claim 1, wherein:

the evaporator includes a flue tube through which the exhaust gas of the internal combustion engine flows and a refrigerant passage which is formed around the flue tube and in which the liquid-phase refrigerant is stored;

a first end of the flue tube is constituted as a fixed end; and

a second end of the flue tube includes a bellows tube for absorbing a change in tube length resulting from thermal expansion of the flue tube.

9. A method for controlling a waste heat recovery apparatus including an evaporator, an expander, a condenser, and a liquid-phase refrigerant supply device, the evaporator being configured to turn a liquid-phase refrigerant into steam through heat exchange with exhaust gas of an internal combustion engine, the expander being configured to expand a gas-phase refrigerant passed through the evaporator to recover heat energy, the condenser being configured to condense the gas-phase refrigerant passed through the expander to return the condensed gas-phase refrigerant to the liquid-phase refrigerant, and the liquid-phase refrigerant supply device being configured to supply the liquid-phase refrigerant delivered from the condenser, to the evaporator, the method comprising:

adjusting an amount of the liquid-phase refrigerant to be supplied to the evaporator by controlling the liquid-phase refrigerant supply device;

receiving operation of the internal combustion engine to bring the supply of the liquid-phase refrigerant by the liquid-phase refrigerant supply device into a stopped state; and

continuing the stopped state until an amount of the liquid-phase refrigerant stored in the evaporator becomes equal to or lower than a predetermined low refrigerant amount during the operation of the internal combustion engine.