Engine waste-heat utilization device

• US 9,562,444 B2
• Filed: 08/06/2012
• Issued: 02/07/2017
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nagai, Hiroyuki, Mizoguchi, Shinichiro, Ishikawa, Takayuki
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): France, Mickey
• Application Number:
  US14/237,977
• Publication Number:
  US 20140165562A1
• Time in Patent Office: 1,646 Days
• Field of Search: 606/14, 606/15, 606/16, 606/18, 606/20, 606/24, 603/20, 603/21
• US Class Current: 1/1
• 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 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: F01K 23/101 Regulating means specially adapted therefor F01K23/105, F01K23/108 take precedence
• CPC Class Codes: F01K 23/14 including at least one combustion engine
• CPC Class Codes: F01N 5/02 the devices using heat
• CPC Class Codes: F01P 2060/16 Outlet manifold
• CPC Class Codes: F01P 2060/18 Heater
• CPC Class Codes: F01P 7/165 characterised by systems with two or more loops
• CPC Class Codes: F02G 5/04 in combination with other waste heat from combustion engines
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An engine-waste-heat utilization device includes a Rankine cycle which includes a heat exchanger through which cooling water coming out from an engine flows to recover waste-heat of the engine to refrigerant, an expander which generates power using the refrigerant coming out from the heat exchanger, a condenser which condenses the refrigerant coming out from the expander and a refrigerant pump which supplies the refrigerant coming out from the condenser to the heat exchanger, and a cooling water passage in which the cooling water having a higher temperature flows when the Rankine cycle is operated than when the Rankine cycle is not operated.

Claims

1. An engine-waste-heat utilization device, comprising:

a Rankine cycle which includes;

a heat exchanger through which waste-heat of cooling water coming out from an engine is recovered to refrigerant;

an expander which generates power using the refrigerant coming out from the heat exchanger;

a condenser which condenses the refrigerant coming out from the expander; and

a refrigerant pump which supplies the refrigerant coming out from the condenser to the heat exchanger;

a cooling water passage in which the cooling water coming out from the engine flows;

a thermostat valve configured to open to allow the cooling water to flow to a radiator at a temperature higher than a predetermined temperature, and to close not to allow the cooling water to flow to the radiator; and

an engine controller configured to switch the predetermined temperature among at least two temperature setting values in accordance with whether the Rankine cycle is operated or not,

wherein the engine controller is further configured to switch the predetermined temperature to a higher temperature setting value in a case where the Rankine cycle is operated compared with a temperature setting value in a case where the Rankine cycle is not operated.

2. The engine-waste-heat utilization device according to claim 1, wherein the cooling water passage includes:

a first cooling water passage which supplies the cooling water coming out from the engine to the radiator;

a second cooling water passage which returns the cooling water coming out from the radiator to the engine; and

a bypass cooling water passage which is branched off from the first cooling water passage, bypasses the radiator, and joins the second cooling water passage.

3. The engine-waste-heat utilization device according to claim 2,

wherein the heat exchanger is provided in the bypass cooling water passage to perform heat exchange between the cooling water flowing in the bypass cooling water passage and the refrigerant.

4. The engine-waste-heat utilization device according to claim 2,

further comprising a heater provided in a vicinity of the thermostat valve,

wherein the thermostat valve is electrically controlled, and the engine controller is further configured to switch the predetermined temperature by turning the heater on or off.

5. The engine-waste-heat utilization device according to claim 4,

wherein the engine controller is further configured to turn the heater off when the Rankine cycle is operated but turn the heater on when the Rankine cycle is not operated.

6. The engine-waste-heat utilization device according to claim 4,

wherein the engine controller is further configured to turn the heater on so that the Rankine cycle is not operated when the engine has a high load.

7. An engine-waste-heat utilization method for a system, the system comprising:

an engine;

a Rankine cycle which includes;

a heat exchanger through which waste-heat of cooling water coming out from the engine is recovered to refrigerant;

an expander which generates power using the refrigerant coming out from the heat exchanger;

a condenser which condenses the refrigerant coming out from the expander; and

a refrigerant pump which supplies the refrigerant coming out from the condenser to the heat exchanger;

a cooling water passage in which the cooling water coming out from the engine flows; and

a thermostat valve configured to open to allow the cooling water to flow to a radiator at a temperature higher than a predetermined temperature, and to close not to allow the cooling water to flow to the radiator,

the method comprising;

switching the predetermined temperature among at least two temperature setting values in accordance with whether the Rankine cycle is operated or not such that the predetermined temperature is switched to a higher temperature setting value in a case where the Rankine cycle is operated compared with a temperature setting value in a case where the Rankine cycle is not operated.