Method and system for a dual loop coolant system

Patent metadata

Field	Value
Publication number	US-9964019-B2
Application number	US-201414547950-A
Country	US
Kind code	B2
Filing date	Nov 19, 2014
Priority date	Nov 19, 2014
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

Methods and systems are provided for a dual loop coolant system used to control an engine transmission oil temperature. In one example, a high temperature coolant loop comprises a first heat exchanger and a control valve positioned upstream of the first heat exchanger whose coolant flow is separate from a second, low temperature coolant loop containing a second heat exchanger. An engine fluid circuit fluidically coupling the first heat exchanger, second heat exchanger, and an engine system component via a bypass valve positioned between the first heat exchanger and the second heat exchanger.

First claim

The invention claimed is:

1. A system, comprising:
a first coolant loop including a first heat exchanger, a first radiator, and a control valve positioned upstream of the first heat exchanger, wherein after coolant exits the first radiator, a portion of the coolant in the first coolant loop flows back to the first radiator while bypassing the first heat exchanger and a remaining portion of the coolant in the first coolant loop flows through the first heat exchanger via the control valve;
a second coolant loop, separate from the first coolant loop, including a second heat exchanger a second radiator, a charge air cooler, and an air conditioning condenser, wherein after coolant exits the second radiator, a portion of coolant in the second coolant loop flows back to the second radiator while bypassing the second heat exchanger and a remaining portion of the coolant in the second coolant loop flows to the second heat exchanger; and
an engine fluid circuit fluidically coupling the first heat exchanger in series with the second heat exchanger, and an engine system component via a bypass valve positioned between the first heat exchanger and the second heat exchanger.

2. The system of claim 1 , wherein the first coolant loop is a high temperature coolant loop comprising at least an engine coolant jacket, the first radiator, and a heater core, wherein the coolant exiting the first radiator flows through the engine coolant jacket and then the portion of the coolant in the first coolant loop flowing back to the first radiator flows through the heater core and the remaining portion of the coolant in the first coolant loop flows to the first heat exchanger when the control valve is open.

3. The system of claim 2 , wherein the second coolant loop is a low temperature coolant loop, wherein after the coolant exits the second radiator, the portion of the coolant in the second coolant loop flowing back to the second radiator flows through one or more of the charge air cooler and the air conditioning condenser, and the remaining portion of the coolant in the second coolant loop flows to the second heat exchanger.

4. The system of claim 3 , wherein the engine fluid circuit is a transmission oil circuit where transmission oil flows, in series, from an engine transmission to the first heat exchanger, then through the bypass valve, and then through the second heat exchanger, and then back to the engine transmission when the bypass valve is open.

5. The system of claim 4 , wherein when the bypass valve is closed, transmission oil flows from the engine transmission to the first heat exchanger and then back to the engine transmission, without flowing through the second heat exchanger.

6. The system of claim 5 , further comprising a controller with computer-readable instructions for:
during a heating operation, opening the control valve to flow coolant from the first coolant loop through the first heat exchanger in order to transfer heat from the remaining portion of the coolant from the first coolant loop to the transmission oil;
during a first cooling operation when coolant in the first coolant loop is greater than a transmission oil temperature, closing the control valve to block the remaining portion of coolant from the first coolant loop from flowing through the first heat exchanger; and
during a second cooling operation when coolant in the first coolant loop is less than the transmission oil temperature, opening the control valve to allow the remaining portion of coolant from the first coolant loop to flow through the first heat exchanger.

7. The system of claim 6 , wherein the computer-readable instructions further comprise instructions for, during one or more of a hold operation or an engine warm up operation, closing the control valve to block the remaining portion of coolant from the first coolant loop from flowing through the first heat exchanger and maintaining a current transmission oil temperature.

8. The system of claim 7 , wherein during the heating operation and the hold operation, the bypass valve is closed, and during each of the first and second cooling operations, the bypass valve is open.

9. The system of claim 7 , wherein the transmission oil flows from the engine transmission, through:
the first heat exchanger, into the bypass valve, and back to the engine transmission during the heating operation;
the first heat exchanger and the bypass valve, into the second heat exchanger, and back to the engine transmission during each of the first and second cooling operations; and
the first heat exchanger, into the bypass valve, and back into the engine transmission during one or more of the hold operation and the engine warm up operation.

10. The system of claim 1 , wherein the control valve is a solenoid-actuated valve or a wax-actuated valve.

11. A method, comprising:
during a first condition, transferring heat from a first coolant loop to a transmission fluid via a first portion of coolant from the first coolant loop flowing through a first heat exchanger, a remaining portion of coolant from the first coolant loop flowing to a first radiator while bypassing the first heat exchanger;
during a second condition, transferring heat from the transmission fluid to a second coolant loop via a second heat exchanger via a second portion of coolant from the second coolant loop flowing through the second heat exchanger, a remaining portion of coolant from the second coolant loop flowing to a second radiator while bypassing the second heat exchanger, the second heat exchanger coupled in series to the first heat exchanger via a bypass valve, the second coolant loop further including a charge air cooler and an air conditioning condenser;
during a third condition, reducing a transfer of heat between the transmission fluid and one or more of the first portion of coolant from the first coolant loop and the second portion of coolant from the second coolant loop; and
during each of the first, second, and third conditions, maintaining coolant in the first coolant loop separate from coolant in the second coolant loop.

12. The method of claim 11 , wherein the transmission fluid comprises engine transmission oil, wherein the first condition is different than and mutually exclusive with the second condition, wherein the first coolant loop further includes a heater core, the remaining portion of coolant from the first coolant loop flowing to the first radiator via the heater core, and the remaining portion of coolant from the second coolant loop flowing to the second radiator via one of the charge air cooler and the air conditioning condenser.

13. The method of claim 11 , wherein transferring heat from the first coolant loop to the transmission fluid via the first heat exchanger comprises:
opening a control valve positioned in the first coolant loop upstream of the first heat exchanger to flow the first portion of coolant from an engine coolant jacket to the first heat exchanger; and
flowing the transmission fluid from an engine component through the first heat exchanger and back to the engine component without flowing through the second heat exchanger.

14. The method of claim 13 , wherein transferring heat from the transmission fluid to the second coolant loop via the second heat exchanger comprises:
closing the control valve to block the first portion of coolant from the engine coolant jacket from flowing through the first heat exchanger when a coolant temperature from the engine coolant jacket is greater than a transmission fluid temperature, and flowing the transmission fluid from the engine component through the first heat exchanger, the second heat exchanger, an

Assignees

• Ford Global Tech Llc

Inventors

• Gopal Ravi

Classifications

• F01P7/165 Primary

  characterised by systems with two or more loops · CPC title

• F01P3/20 Primary

  Cooling circuits not specific to a single part of engine or machine (F01P3/22 takes precedence) · CPC title

• F01P2060/045

  for transmissions · CPC title