Cooling circuit for internal combustion engines

• US 10,450,938 B2
• Filed: 05/23/2014
• Issued: 10/22/2019
• Est. Priority Date: 05/23/2014
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nagai, Hiroyuki
• Primary Examiner(s): Low, Lindsay M
• Assistant Examiner(s): Holbrook, Teuta B
• Application Number:
  US15/312,750
• Publication Number:
  US 20170184008A1
• Time in Patent Office: 1,978 Days
• Field of Search: 123 4101, 123 4102, 123 4105, 123 4108, 123 4109, 123 411, 123 4112, 123 4129, 123 413, 123 4144
• CPC Class Codes: F01N 5/02 the devices using heat
• CPC Class Codes: F01P 11/20 concerning atmospheric freezing conditions, e.g. automatically draining or heating during frosty weather
• CPC Class Codes: F01P 2060/16 Outlet manifold
• CPC Class Codes: F01P 2060/18 Heater
• CPC Class Codes: F01P 3/02 Arrangements for cooling cylinders or cylinder heads
• CPC Class Codes: F01P 3/20 Cooling circuits not specific to a single part of engine or machine F01P3/22 takes precedence
• CPC Class Codes: F01P 7/167 by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed
• CPC Class Codes: F02B 29/0412 Multiple heat exchangers arranged in parallel or in series
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A cooling circuit for internal combustion engines includes an internal combustion engine, a pressure-feeding unit for feeding coolant, which cools the internal combustion engine under pressure, a valve unit having a plurality of heat exchangers connected in parallel thereto, an exhaust heat recovery system for recovering heat from exhaust air of the internal combustion engine by the coolant, a first circulation circuit including the pressure-feeding unit, the valve unit and the exhaust heat recovery system, and a second circulation circuit including the pressure-feeding unit and the exhaust heat recovery system.

Claims

1. A cooling circuit for an internal combustion engine, comprising:

an internal combustion engine;

a pressure-feeding pump configured to feed coolant under pressure, the coolant cooling the internal combustion engine;

a valve unit having a plurality of heat exchangers connected in parallel thereto and configured to change a coolant flowing state in the plurality of heat exchangers;

an exhaust heat recovery system configured to recover heat from exhaust air of the internal combustion engine by the coolant;

a first circulation circuit including the pressure-feeding pump, the valve unit and the exhaust heat recovery system; and

a second circulation circuit not including the valve unit and including the pressure-feeding pump and the exhaust heat recovery system,

wherein a flow rate of the coolant flowing through the exhaust heat recovery system via the second circulation circuit is made smaller than that of the coolant flowing through the exhaust heat recovery system via the first circulation circuit by an orifice arranged in the second circulation circuit or by a passage of the second circulation circuit, and the pressure-feeding pump is a mechanical pump driven by power of the internal combustion engine.

2. The cooling circuit according to claim 1, wherein:

the valve unit is arranged upstream of the exhaust heat recovery system in the first circulation circuit; and

the second circulation circuit is branched off from the first circulation circuit at a position upstream of the valve unit and joins the first circulation circuit between the valve unit and the exhaust heat recovery system.

3. The cooling circuit according to claim 2, wherein:

the valve unit has a valve opening pattern configured to shut off all circulation circuits passing through the valve unit including the first circulation circuit.

4. The cooling circuit according to claim 3, wherein:

the plurality of heat exchangers includes

a heater to heat an inside of a cabin of a vehicle mounted with the internal combustion engine through heat radiation from the coolant;

a cooler to cool lubricating oil of a transmission configured to change a speed of output rotation of the internal combustion engine through heat radiation to the coolant; and

a radiator configured to radiate heat of the coolant; and

the valve unit includes

a valve opening pattern configured to cause the coolant to flow through the heater out of the plurality of heat exchangers;

a valve opening pattern configured to cause the coolant to flow through the heater and the cooler out of the plurality of heat exchangers; and

a valve opening pattern configured to cause the coolant to flow through the heater, the cooler and the radiator out of the plurality of heat exchangers.

5. The cooling circuit according to claim 4, wherein:

the valve unit includes a valve opening pattern configured to cause the coolant to flow only through the radiator out of the plurality of heat exchangers.

6. The cooling circuit according to claim 1, wherein:

the valve unit is arranged downstream of the exhaust heat recovery system in the first circulation circuit; and

the second circulation circuit is branched off from the first circulation circuit between the exhaust heat recovery system and the valve unit and joins the first circulation circuit at a position downstream of the valve unit.

7. The cooling circuit according to claim 6, wherein:

the valve unit has a valve opening pattern configured to shut off all circulation circuits passing through the valve unit including the first circulation circuit.

8. The cooling circuit according to claim 1, wherein:

the plurality of heat exchangers includes a heater configured to heat an inside of a cabin of a vehicle mounted with the internal combustion engine through heat radiation from the coolant; and

the first circulation circuit further includes the heater.

9. The cooling circuit according to claim 1, wherein:

the plurality of heat exchangers includes a cooler configured to cool lubricating oil of a transmission configured to change a speed of output rotation of the internal combustion engine through heat radiation to the coolant; and

the first and second circulation circuits further include the cooler, and the exhaust heat recovery system is arranged upstream of the cooler.

10. The cooling circuit according to claim 1, wherein:

the exhaust heat recovery system includes a heat exchanger configured to perform heat exchange between the exhaust air and the coolant;

the exhaust heat recovery system is configured as a bypass-less exhaust heat recovery system configured to cause flowing-in exhaust air to flow via the heat exchanger.

11. The cooling circuit according to claim 1, wherein:

the second circulation circuit circulates the coolant in a state where the pressure-feeding pump is feeding the coolant under pressure.