METHOD FOR OPERATING A COOLANT CIRCUIT

• US 20130167784A1
• Filed: 01/02/2013
• Published: 07/04/2013
• Est. Priority Date: 01/02/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Quix, Hans Guenter, Mehring, Jan, Lach, Rainer
• Granted Patent: US 10,161,361 B2
• Time in Patent Office: Days
• US Class Current: 123/41.1
• CPC Class Codes: F02M 26/28 with liquid-cooled heat exchangers
• CPC Class Codes: F02M 26/33 controlling the temperature of the recirculated gases

Abstract

A method for operating a liquid coolant circuit of an internal combustion engine is described in which the coolant circuit contains an integrated EGR cooler such that the cooling system has a single circuit with two operational modes. The method includes a controller that can switch between operational modes to enable delivery of coolant to the EGR cooler when the flow of coolant through the block cooling circuit is blocked. In the second operational mode, the method also includes using an auxiliary pump to pass coolant to the EGR cooler while bypassing the main coolant pump, which can occur by adjusting the flow of coolant through the circuit so the flow through a bypass line is reversed relative to the inherent forward direction of flow in the bypass line during the first operational mode.

Claims

1. A method for operating a coolant circuit of an internal combustion engine, in which the coolant circuit includes:

at least one main coolant pump, and

at least one block cooling circuit, and

at least one EGR cooler, the EGR cooler connected at least to a heat exchanger circuit, the method comprising;

determining whether the flow through a block cooling circuit is to be stopped based on a temperature within the circuit,

switching a control valve to stop the flow of coolant in the block cooling circuit,

determining whether recirculated exhaust gases are to be cooled, and

in response to sensors within the cooling system, activating an auxiliary coolant pump to pass coolant to the EGR cooler via a bypass of the block coolant circuit coupled to a connecting line upstream of the main coolant pump, wherein the coolant bypasses said main pump.

2. The method of claim 1, further comprising operating the block coolant circuit in a no flow status during a warm-up phase of the engine following an engine cold start.

3. The method of claim 1, wherein a direction of coolant flow through the bypass line relative to an inherent direction of flow is reversed when the block coolant circuit operates in the no flow status and when the recirculated exhaust gases are cooled.

4. The method of claim 3, wherein a position of at least one flow valve is switched to adjust the flow of coolant through the circuit in response to activating the auxiliary coolant pump.

5. The method of claim 4, wherein the main coolant pump is shut-down when reversed flow of coolant through the bypass line bypasses said main pump.

6. The method of claim 1, wherein the heat exchanger operate as a vehicle passenger compartment heater.

7. The method of claim 1, wherein the internal combustion engine includes a split cooling system.

8. A method for operating an engine liquid-coolant circuit, comprising:

during a first mode, flowing coolant through a radiator bypass line in a first flow direction, and

during a second mode flowing coolant through the bypass line in a reverse direction and then to a heat exchanger.

9. The method of claim 8, wherein the heat exchanger is an EGR cooler.

10. The method of claim 8, wherein the flow of coolant in the first mode is at least one of:

blocked and unblocked.

11. The method of claim 8, further comprising switching to the second mode from the first mode by changing a position of a valve.

12. The method of claim 11, wherein the second mode includes circulating coolant through a second circuit via an auxiliary pump.

13. The method of claim 12, wherein a main coolant pump is deactivated during the second mode.

14. The method of claim 8, wherein a control system selects from among the first and second modes based on an engine cold start and warm-up condition.

15. The method of claim 8 wherein the heat exchanger is a heater core of a passenger compartment heating system.

16. The method of claim 15 further comprising blowing passenger compartment heating air through the heater core.

17. A method for operating an engine liquid-coolant circuit, comprising:

during a first mode, flowing coolant through a radiator bypass line in a first flow direction via operation of a first pump, and

during a second mode flowing coolant through the bypass line in a reverse direction and then to a heat exchanger via operation of a second pump.

18. The method of claim 17 wherein the heat exchanger is a heater core of a passenger compartment heating system.

19. The method of claim 17, wherein the heat exchanger is an EGR cooler.