Exhaust heat recovery device

Patent metadata

Field	Value
Publication number	US-9970329-B2
Application number	US-201415021666-A
Country	US
Kind code	B2
Filing date	Sep 11, 2014
Priority date	Sep 12, 2013
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

In an exhaust heat recovery device provided with a Rankine cycle device, a clutch for transmitting and interrupting power between an engine and the Rankine cycle device is released appropriately to prevent the Rankine cycle from becoming a load on the engine. An exhaust heat recovery device 1 A includes a Rankine cycle device 2 A, a power transmission mechanism 3 A, and a control unit 4 . The power transmission mechanism 3 A has a clutch 31 and is capable of transmitting power between an engine 10 and the Rankine cycle device 2 A when the clutch 31 is engaged. The control unit 4 A controls the engagement and disengagement of the clutch 31 based on a first correlation value correlated with consumed power when the Rankine cycle device 2 A is started, and a second correlation value correlated with consumed power of the Rankine cycle device 2 A when the output of the Rankine cycle device 2 A is negative during the operation of the Rankine cycle device 2 A after the start-up.

First claim

The invention claimed is:

1. An exhaust heat recovery device comprising:
a Rankine cycle device that is provided with: a heater configured to heat and vaporize a refrigerant with exhaust heat of an engine; an expander configured to expand the refrigerant passed through the heater to generate power; 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, the heater, the expander, the condenser, and the pump being arranged in a refrigerant circulation passage;
a power transmission mechanism that has a clutch and is capable of transmitting power between the engine and the Rankine cycle device when the clutch is engaged; and
a clutch control unit that controls engagement and disengagement of the clutch based on a first correlation value correlated with consumed power when the Rankine cycle device is started, and a second correlation value correlated with consumed power of the Rankine cycle device when the output thereof is negative during operation thereof after start-up,
wherein the clutch control unit disengages the clutch when an absolute value of the second correlation value is greater than or equal to an absolute value of the first correlation value during the engagement of the clutch.

2. The exhaust heat recovery device according to claim 1 , wherein the clutch control unit disengages the clutch when the absolute value of the second correlation value is greater than or equal to the absolute value of the first correlation value and output of the Rankine cycle device is on a downward trend during the engagement of the clutch.

3. The exhaust heat recovery device according to claim 1 , further comprising an output computing unit for computing the output of the Rankine cycle device,
wherein the first correlation value and the second correlation value are calculated based on output from the output computing unit.

4. The exhaust heat recovery device according to claim 3 , wherein
the consumed power when the Rankine cycle device is started is an integrated value of output of the Rankine cycle device during a period from when the Rankine cycle device is started up until the output of the Rankine cycle device becomes positive, and
the consumed power of the Rankine cycle device when the output thereof is negative during operation thereof after the start-up is an integrated value of negative output of the Rankine cycle device during the operation thereof.

5. An exhaust heat recovery device comprising:
a Rankine cycle device that is provided with: a heater configured to heat and vaporize a refrigerant with exhaust heat of an engine, an expander configured to expand the refrigerant passed through the heater to generate power, 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, the heater, the expander, the condenser, and the pump being arranged in a refrigerant circulation passage;
a power transmission mechanism that has a clutch and is capable of transmitting power between the engine and the Rankine cycle device when the clutch is engaged;
an output computing unit that computes output of the Rankine cycle device; and
a clutch control unit that disengages the clutch when a state in which the output of the Rankine cycle device is zero or negative is continued during the engagement of the clutch,
wherein the clutch control unit disengages the clutch when an absolute value of an integrated value of negative output of the Rankine cycle device becomes greater than or equal to predetermined threshold value during the engagement of the clutch.

6. The exhaust heat recovery device according to claim 5 , wherein the clutch control unit disengages the clutch when the absolute value of the integrated value of negative output of the Rankine cycle device is greater than or equal to the predetermined threshold value and the output of the Rankine cycle device is on a downward trend during the engagement of the clutch.

7. The exhaust heat recovery device according to claim 3 ,
wherein the pump is a mechanical pump driven by the engine,
wherein the output computing unit computes the output of the Rankine cycle device based on a pressure difference between a high-pressure side pressure and a low-pressure side pressure of the Rankine cycle device, a rotational speed of the expander, and a rotational speed of the mechanical pump.

8. The exhaust heat recovery device according to claim 1 , wherein the pump is a mechanical pump driven by the engine.

9. The exhaust heat recovery device according to claim 8 , wherein the expander and the mechanical pump are integrally connected.

10. The exhaust heat recovery device according to claim 1 , wherein the expander is a scroll-type expander that has a fixed scroll and a movable scroll and generates power by expanding the refrigerant in an expansion chamber formed between the fixed scroll and the movable scroll, and a ball-coupling type anti-rotation mechanism using balls as rolling elements is provided to prevent the rotation of the movable scroll.

11. The exhaust heat recovery device according to claim 10 , wherein even when a liquid refrigerant is likely to be mixed into the expander during the engagement of the clutch, the clutch control unit maintains an engagement state of the clutch until an absolute value of the second correlation value becomes greater than or equal to an absolute value of the first correlation value, or until an absolute value of an integrated value of negative output of the Rankine cycle device becomes greater than or equal to a predetermined threshold value.

12. The exhaust heat recovery device according to claim 5 ,
wherein the pump is a mechanical pump driven by the engine,
wherein the output computing unit computes the output of the Rankine cycle device based on a pressure difference between a high-pressure side pressure and a low-pressure side pressure of the Rankine cycle device, a rotational speed of the expander, and a rotational speed of the mechanical pump.

13. The exhaust heat recovery device according to claim 5 , wherein the pump is a mechanical pump driven by the engine.

14. The exhaust heat recovery device according to claim 5 , wherein the expander is a scroll-type expander that has a fixed scroll and a movable scroll and generates power by expanding the refrigerant in an expansion chamber formed between the fixed scroll and the movable scroll, and a ball-coupling type anti-rotation mechanism using balls as rolling elements is provided to prevent the rotation of the movable scroll.

15. The exhaust heat recovery device according to claim 9 , wherein the expander is a scroll-type expander that has a fixed scroll and a movable scroll and generates power by expanding the refrigerant in an expansion chamber formed between the fixed scroll and the movable scroll, and a ball-coupling type anti-rotation mechanism using balls as rolling elements is provided to prevent the rotation of the movable scroll.

16. An exhaust heat recovery device comprising:
a Rankine cycle device that is provided with: a heater configured to heat and vaporize a refrigerant with exhaust heat of an engine; an expander configured to expand the refrigerant passed through the heater to generate power; 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, the heater, the expander, the condenser, and the pump being arranged in a refrigerant

Assignees

• Sanden Holdings Corp

Inventors

• Tanaka Yuuta

Classifications

• F02G5/00

  Profiting from waste heat of combustion engines, not otherwise provided for · CPC title

• F01K23/065

  the combustion taking place in an internal combustion piston engine, e.g. a diesel engine · CPC title

• F01K15/02

  for driving vehicles, e.g. locomotives · CPC title

• F01K23/101 Primary

  Regulating means specially adapted therefor (F01K23/105, F01K23/108 take precedence) · CPC title

• F02G5/02

  Profiting from waste heat of exhaust gases · CPC title